مهندسی عمران امیرکبیر (2588297X)(2)pp. 363-378
به منظور کاهش خسارتهای ناشی از زمینلغزش، شناسایی پهنههای دارای پتانسیل خطر زمینلغزش و به نقشه در آوردن آنها امری ضروری و اجتنابناپذیر است. برای انجام این امر، روشهای متعددی توسط محققین در کشورهای مختلف مورد استفاده قرارگرفته است که هر یک از آنها تحت شرایط ویژهای ارائه شدهاند. در این تحقیق، پس از تهیهی نقشه پراکنش زمینلغزشهای قدیمی و بررسی عوامل مؤثر در زمینلغزشهای محدوده مخزن سد بهشتآباد و نیز مقایسه هریک از روشهای پهنهبندی و محل ابداع این روشها با مورد مطالعه، روشهای تجربی نیلسن و مورا-وارسون به همراه روش آماری دومتغیره و روش شبکهی عصبی مصنوعی برای پهنهبندی خطر زمینلغزش انتخاب شدهاند. در ادامه پس از تهیهی نقشههای پهنهبندی خطر زمینلغزش، برای ارزیابی دقت این نقشهها، از روشهای احتمال تجربی، اندیس لغزش و نیز ترسیم منحنی ROC استفاده شده است. در نهایت نتایج حاصل از ترسیم منحنی ROC و محاسبه سطح زیر این منحنی مبنای ارزیابی دقت روشهای پهنهبندی قرار گرفت که نتیجه آن در این محدوده، انتخاب روش آماری و روش شبکهی عصبی مصنوعی(ANN) به عنوان روشهایی مناسب برای تهیهی نقشهی پهنهبندی خطر زمینلغزش بوده است.
Geomechanics and Geoengineering (17486025)
This study systematically examines the effects of these fibres at varying contents (0% to 0.5%), their combinations, cement content (0% to 12%), partial cement replacement with biopolymer (0% to 55%) and curing conditions (moisture-preserved and air-cured) on the UCS of soil. The optimal fibre content, which varied between 0.25% and 0.5% depending on the fibre type, corresponded to the highest UCS values achieved for each case. Additionally, the results demonstrated a consistent and significant increase in UCS with increasing cement content, reaching a maximum at 12% cement. The UCS of untreated soil was 447 kPa. The maximum increase in UCS for fibre-reinforced specimens was observed with 0.5% virgin polypropylene fibres, resulting in a 100% improvement. Among the stabilisers tested, cement demonstrated the most significant improvement in UCS, with a maximum increase of 414%. The optimal biopolymer content of 2.75% improved UCS by approximately 71%, showing a substantial gain over untreated soil. Although replacing cement with biopolymer resulted in a slight reduction in UCS compared to cement-only specimens, this substitution offers environmental advantages by reducing cement consumption. To correlate strength gains with internal structure, Scanning Electron Microscopy (SEM) analysis was conducted to observe microstructural changes in the treated specimens. © 2025 Informa UK Limited, trading as Taylor & Francis Group.
Construction and Building Materials (09500618)452
Porosity is among the basic physical parameters widely used in evaluating the strength characteristics of building stones. Based on the geometric shape of the stone specimen, there are two procedures for determining the porosity: 1) measurements on specimens with regular shapes and 2) measurements on specimens with irregular shapes. The present study correlates the strength characteristics of stones and porosities measured from specimens with regular and irregular shapes. To this end, samples of carbonate stones were collected from different locations in Iran. The porosity of the samples was measured for specimens with regular (nr) and irregular (nir) shapes. Next, the strength characteristics of the samples, including uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), and point load index (PLI), were determined. Results revealed that for all samples, nr has lower values than nir. Based on the scanning electron microscope (SEM) micrographs, this difference is due to the filling of some pore spaces of the specimens with regular shapes during their preparation by the coring machine. UCS, BTS, and PLI(50) were correlated with nr and nir using simple regression analyses. The accuracy of the correlation equations was compared based on their determination coefficient (R2) and diagonal line (1:1) measures. The findings indicated that nir provides higher accuracy than nr in evaluating the UCS, BTS, and PLI(50) of the samples. The effect of dry density (ρd) on the correlations between UCS, BTS, and PLI(50) with nir was investigated using multiple regression analyses. According to the results, ρd has a positive role in the prediction accuracy of the UCS, BTS, and PLI(50). The validity and accuracy of multiple regression equations were verified according to the statistics criteria and the published data by various researchers. Using these equations obviates the need to perform the UCS, BTS, and PLI(50) tests as time-consuming and laborious efforts. © 2024 Elsevier Ltd
Ajalloeian, R.,
Dardashti a., A.F.,
Rostami j., ,
Hassanpour j., J.,
Salimi a., ,
Dardashti a., A.F.,
Rostami j., ,
Ajalloeian, R.,
Hassanpour j., J.,
Salimi a., 2025 29th International Computer Conference, Computer Society of Iran, CSICC 2025pp. 2995-3004
Despite the widespread use of TBMs in tunneling projects, accurate estimation of TBM performance, especially in various geological conditions, can still be challenging. Comparing the most common rock mass classification systems, the RMR classification system shows a better correlation with the TBM penetration rate, due to using uniaxial compressive strength (UCS) as an input parameter in this classification system. RMR parameters are available in most tunneling projects, but it should be noted that the RMR system, was developed to classify the rock mass conditions in terms of tunnel stability and support design, and the effective parameters were selected accordingly. So, when the target is to use the RMR input parameters to predict the TBM performance, modifications should be made in the parameters. This study is offered a new TBM performance prediction model based on the input parameters of the Basic RMR in different rock types, through machine learning-based regression analysis. The proposed model has been developed based on the analysis of a comprehensive database of TBM performance in various rock types. Because different rock types have different fabrics and respond differently to shear forces, incorporating the effects of rock type into performance prediction models can improve the accuracy of estimates, for this reason, the lithology parameter is also included in the model. The model can be practical, especially in the design phase of a tunneling project. © 2024 The Author(s).
Geotechnical and Geological Engineering (09603182)42(1)pp. 675-685
Uniaxial compressive and Brazilian tensile strengths (UCS and BTS) of rocks are considered important properties in the design of most the geotechnical projects that interact with rock such as slope stability and underground excavation. Indirect tests such as Schmidt hammer hardness (SH) can be used for prediction of UCS and BTS of rocks. The aim of this study is to correlate the UCS and BTS of granitic rocks with SH with an emphasis on influence of petrographic characteristics. For this purpose, 10 different granitic rocks were selected from Iran’s quarries and their UCS, BTS, SH and petrographic characteristics including mean mineral grain size (MGS) and mineralogical composition (Quartz/Feldspar ratio) (Qz/Fl) were determined. Using data analysis, correlation between UCS and BTS with SH, MGS and Qz/Fl statistically were investigated using multiple regression analyses. In these analyses, the UCS and BTS were considered to be the dependent variable, which are dependent on the independent variables of the SH, MGS and Qz/Fl. It was found out that there are moderate correlations (R2 = 0.523 to 0.759) between UCS and BTS with SH, whereas there are strong correlations (R2 = 0.868 to 0.955) between UCS and BTS with SH when MGS and Qz/Fl are considered. Finally, it was concluded that the regression equations proposed in this study are in good accuracy for prediction of UCS and BTS, and thus making a rapid assessment from UCS and BTS of granitic rocks. © Springer Nature Switzerland AG 2020.
Dardashti a., A.F.,
Ajalloeian, R.,
Rostami j., ,
Hassanpour j., J.,
Salimi a., Rock Mechanics and Rock Engineering (07232632)57(1)pp. 739-755
In mechanized tunneling, the ability to accurately predict the performance of the tunnel boring machine (TBM) is critical, because of its impacts on the project schedule and cost. A substantial amount of research has been conducted on predicting the penetration rate of TBMs in rocks but sometimes the actual cutting process of the disc cutter has been ignored, as most of the available models have been developed based on the assumption that the chipping process is the dominant mode of rock breakage. This might be true in many cases, but there are also situations where tensile fractures do not extend long enough to form chips, instead the tracks get deeper, and fines and rock powder are generated instead of chipping. This situation happens when the cutter load is insufficient to form chips, or so called sub-critical loading occurs. Two of the recent tunneling projects where subcritical cutter load has been the dominant mode are the southern extension of Tehran subway Line 6 (SEL6), and the southern lot of Kerman water conveyance tunnel (KrWCT). The issue in SEL6 was insufficient thrust of the machine and in KrWCT the high strength of the rock. Evaluation of the FPIs in SEL6 shows that the FPIs were less than 100 (kN/cutter/mm/rev) and the prediction errors of the existing models are low. However, in KrWCT project in rocks with higher strength and higher FPIs, the prediction errors are considerable. This indicates that the common models cannot offer an accurate estimate of the performance of TBM in subcritical loading in rocks with high strength. This study attempts to use statistical and machine learning methods to develop a new relation for TBM performance prediction in such conditions based on actual machine operating data and rock engineering geological features. New equations are introduced for the estimation of FPI in subcritical loading conditions to achieve more reliable and accurate prediction of TBM penetration rate. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.
Innovative Infrastructure Solutions (23644176)9(6)
This paper comprehensively focuses on the wetting–drying (W–D) behavior of carbonated marl soil, treated by a geopolymer utilizing alkali-activated milled recycled glass (MRG) and ordinary Portland cement. The effect of the stabilizer ratio (5%, 10%, 15%), curing times and temperature (24 h under 25 °C and 50 °C), sample preparation procedure (curing under a pressure of 200 kPa and in an oven), alkaline concentration (2, 4, 6 mol/L), pH, and different W–D cycles (1, 3, and 12 cycles) were assessed. Furthermore, this article explores the failure behavior of samples, a fact that has received limited attention in previous studies. Binding phases were examined using XRD, FTIR, and SEM–EDS techniques to analyze crystallinity and functional groups in stabilized specimens. The findings indicated greater efficiency in stabilization with lower alkaline activator concentration (2 mol/L), higher glass powder content (15%), and longer curing (90 days), which is abbreviated as 15S2M. Nonetheless, an excessive alkali content of 6 mol/L had adverse effects, leading to a decrease in the strength of the final product and a change in the failure pattern. Visual observations post UCS testing revealed four distinct failure modes, varying based on specific mixtures and curing times. In natural marl samples, irrespective of curing time, the failure surface and deformed shape exhibited a variation in cross-sectional area, with unclear failure planes resulting in a bulging or buckling failure mechanism. Notably, in low alkaline concentration scenarios and high MRG content, as well as in cement-stabilized samples, identifiable failure planes were observed, indicating shearing along a single plane or a sliding mode. The results also demonstrate the superior durability of cement-based samples during W–D cycles. © Springer Nature Switzerland AG 2024.
KSCE Journal of Civil Engineering (12267988)27(9)pp. 3729-3739
Many available stabilisers and reinforcements have been used to enhance the mechanical characteristics of silica sand. So far, many studies have been carried out to understand the influence of various old and new additives such as natural and synthetic fibres or traditional stabilisers on the mechanical characteristics of silica sands. However, there is minimal study on the mechanical characteristics of stabilised or reinforced calcareous sands. The main focus of the current study was to evaluate the influences of relative density (Dr), Portland cement (C) content, rice husk ash (RHA) content and synthetic polypropylene fibre (PPF) content on the mechanical characteristics of a calcareous sand, which were: Dr [30%, 80%], C [0, 3%, 5%, 7.5%], RHA [0, 7%, 7.5%, 10%], and PPF [0%, 1%]. For this purpose, direct shear tests have been conducted on treated calcareous sand subjecting to three curing times (7, 14, and 28 days). The test results indicate that adding cement, rice husk ash and polypropylene fibre increases the shear strength and reduces the volumetric strain under shear loading. The specimens containing 7.5% cement and 7.5% RHA generally exhibited the highest shear strength and the lowest volumetric strain. Relative density, cement content, RHA content, fibre content and curing time have more important effects on the cohesion than the friction angle of treated specimens. © 2023, Korean Society of Civil Engineers.
Case Studies in Construction Materials (22145095)18
The mechanical properties of calcareous sands are critical as potentially important material sources for marine geotechnical constructions. Brittleness and large deformations created in calcareous sands can affect the stability of marine structures and geosynthetic reinforcement is a promising new approach. In this study, a series of consolidated-drained (CD) tests were conducted to evaluate the mechanical properties and deformation of woven geotextile-reinforced calcareous sand. For this purpose, the effect of geotextile layers, relative density, type of woven geotextile, and confining pressure were investigated. The results show that the strength of the reinforced specimens increases markedly compared to the unreinforced calcareous sand and the deviatoric stress-strain curves change from slight softening to hardening and dilatancy. Also, by increasing the number of woven geotextile layers and applying a confining pressure, the shear deformation shifts toward strain-hardening behavior. Overall, woven geotextiles significantly improve the apparent cohesion strength of calcareous sand soil. The woven geotextile, relative density, and confining pressure all contribute to volumetric changes and dilatancy of reinforced specimens, but particle breakage is more affected by confining pressure. © 2023 The Authors
Bulletin of Engineering Geology and the Environment (14359537)81(5)
Expansion of agriculture and industry has led to the growing exploitation of groundwater resources and groundwater level decline in the Isfahan-Borkhar plain. The steady decline in groundwater in susceptible areas has resulted in land subsidence. In this research, the subsidence level of the plain was measured between 2014 and 2017 using radar interferometry technique. On the other hand, the effects of groundwater level decline and aquifer parameters (e.g., alluvium thickness, fine-grained sediments percentage, hydraulic conductivity, storage coefficient, water level, and water level decline) on the subsidence were evaluated. To this end, the deformation in areas where the radar interferometry technique has failed to measure due to significant vegetation cover was estimated using an artificial neural network (ANN)-based model. This model was developed to predict the subsidence amount at any point, assuming that all parameters affecting the occurrence of this phenomenon are known. Next, the sensitivity analysis was performed using trained model parameters to determine the parameter with the highest impact on the subsidence event in the study area. The modeling results showed that the model could predict the subsidence with high accuracy. The most effective parameters in the subsidence event in this area were water level decline and fine-grained sediments percentages. Overall, comparing the subsidence level estimated from time series analysis with changes in groundwater level at some piezometers demonstrates the high impact of fine-grained sediments on the subsidence event in the area. © 2022, Springer-Verlag GmbH Germany, part of Springer Nature.
Case Studies in Construction Materials (22145095)17
The process of freezing and thawing has a great effect on different aspects of materials in cold regions. Due to the complex behavior of materials under the impact of freezing and thawing, several studies conducted on the individual behavior of soil materials or asphalt concrete on this condition. In the present study, the impact of freezing and thawing on the strength characteristics and interaction ratio of soil materials from classes GC (clayey gravel) and GP (poorly graded gravel) at the interface between asphalt and soil materials was assessed. The particle size distribution of the aggregate used in this study was within the grading range recommended by the International Commission on Large Dams (ICOLD) and Fuller's ideal grading curve used in the construction of Mijran Dam, Mazandaran Province, Iran. First, granular materials and asphalt concrete were subjected to weight loss test and durability study, respectively, according to AASHTO-T103 and Iranian Standard 12728. Then, utilizing a large-scale direct shear machine, the contact surface element (interface between granular materials and asphalt concrete) was evaluated under dry and saturated conditions as well as under various freeze-thaw cycling (FTC). The results demonstrate that an increase in the number of FTC let to a decrease in the maximum shear stress under dry and saturated circumstances for both clayey gravels and poorly graded gravels materials at interference with asphalt concrete. In GC materials at the contact surface with asphalt concrete, the interaction ratio reduces by 0.22 % under dry conditions and by 0.54–1.2 % under saturated conditions, relative to its value in the tenth cycle, as the number of FTC increases. In GP materials at the interface with asphalt concrete, as the number of FTC increases, the interaction ratio drops between 9.2 % and 33.61 % in dry conditions and by 20.62 % in saturated situations compared to the value that occurred in 10 cycles. © 2022 The Authors
Case Studies in Construction Materials (22145095)16
In recent years, the tendency to use asphalt concrete cores in earth dams is very common and is increasing. In such dams, the interaction between asphalt concrete core and soil materials has an important role in dam stability. The present study, as a case study of Mijran Dam located in Ramsar area in Iran, has evaluated experimentally the mechanical behavior of the interface between the filter soil material and the asphalt concrete core in the laboratory. In this regard, the samples were tested using large-scale direct shear machine in different normal stresses and in dry and saturation conditions. Also, tests have been performed on samples with different percentages of bitumen and relative density of filter materials at different shear rates and under different freeze-thaw cycles. In all the above conditions, the shear surface has been considered as the interface and the shear rate used in different tests varied in the amounts of 0.5, 1, 1.5 and 3 mm/min. The results of this study show that different percentages of bitumen used do not have such an effect on the shear strength parameters of interface. As the relative density increases, the values of the shear parameters increase. If the sample is dry or saturated, parameters such as dilation angle and shear stiffness increase with increasing density, but the interaction ratio increases in the dry state and decreases in the saturated state. As the shearing rate increases, the dilation angle and interaction ratio in the interface materials increase by about 2–3%. On the contrary, increasing the freeze-thaw cycles reduces the mentioned strength parameters. © 2022
Environmental Earth Sciences (18666299)81(2)
The Meymand world heritage site (Kerman Province, Iran) is a rock-hewn village carved within a pyroclastic rock mass, Meymand Tuff. This site, having an ancient local population with an age of 2000 years, is hosted by a weak rock exposed to deterioration and weathering processes. However, our understanding of the characteristics of the Meymand Tuff is limited to some previous general studies. Therefore, in the present study, the stratigraphy and intrinsic characteristics of the Meymand tuff are investigated to determine its weathering behavior and durability. For this purpose, comprehensive field and laboratory investigations were carried out. The stratigraphy of the valley and the pyroclastic flows that had deposited the Meymand tuff were identified and outlined based on field investigations and many surveyed sections along the Meymand valley. Next, the mineralogical composition, texture, structure, physical and mechanical properties, water absorption rate, slake durability, wetting–drying durability, shrinkage potential of the fine portion, and collapse potential of the Meymand tuff were assessed through laboratory investigations. The results revealed that two pyroclastic flows had deposited the host tuff rocks of the Meymand site. These rocks have a heterogeneous texture comprising very coarse-grained clasts to the fine-grained matrix. Rock characteristics including heterogeneous texture, high porous and open structure, clay-rich mineralogical composition, high water absorption capacity, and swelling and shrinkage potential of the fine portion of the matrix have resulted in adverse behaviors in Meymand tuff. These behaviors are pertained to the strength softening, weight loss, and deterioration at wetting drying cycles. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Construction and Building Materials (09500618)314
There are different tests for measuring aggregate abrasion/degradation resistance, which simulated the destruction conditions in various applications of aggregate. Although these tests have been used for a long time, the process of changing the aggregate shape after the test is still not well known. These changes could be an essential factor in the quality of aggregate materials during their life cycle and play a vital role in the simulated model of aggregate degradation. In this study, the aggregate shape properties in terms of form, angularity, and surface texture are investigated and compared before and after the AAD tests by image analysis techniques. Two common types of coarse aggregates were selected, i.e., limestone and andesite. The AAD tests include different standard test methods, i.e., Micro-Deval (MD), Los Angeles abrasion losses (LAAL), aggregate crushing value (ACV), and aggregate impact value (AIV) were conducted. The results indicated that the change of aggregate shape is based on AAD tests and rock type. The heterogeneity in the mechanism of AAD tests led to the different changes in aggregate morphology and also to opposite behavior due to rock type in texture. The changes in surface texture and angularity are very different, although changes in form have the same trend after LAAL, ACV, and AIV tests. The results showed that the shape changes of the aggregates are affected by both the test type and rock type. The behavior of ACV, AIV, and LAAL in shape changes is similar and is different from MD. The knowledge obtained from this research presents a primary step concerning the numerical modeling and quantitative evaluation of the AAD tests. © 2021
Engineering Geology (00137952)298
Rock aggregates have widespread applications in construction projects, and their engineering properties play a key role in their application. Aggregate's engineering properties are affected by their inherited petrographic characteristics. In this paper, the impact of various petrographic characteristics on the engineering properties of crushed limestone is evaluated. Petrographic analyses and common quality control aggregate tests were performed on 25 carbonate rock samples. The engineering tests conducted include Los Angeles abrasion value (LAAV), aggregate crushing value (ACV), slake durability index (SDI), magnesium sulfate soundness (SS), and water absorption (WA). Also, the petrographic analyses performed on thin sections involved calculating the percentage of fossil grains (FG), non-fossil grains (NFG), meso-scale porosity and voids (LP), micro-scale porosity and voids (SP), micrite (M), sparite (S), dolomitic grains and cement (D), quartz and chert (Q), clay (C), and opaque minerals (O). Statistical analyses were applied to the dataset to evaluate the correlation and obtain the possible relationships between aggregates engineering and petrographic properties. The results indicated that C, LP, O, and SP have an important effect on the engineering properties of carbonate aggregates. Multiple regression analyses were conducted and R2 values higher than 0.84 were obtained, except for the SS. These equations were evaluated by using various data obtained from scientific resources, and their error values were calculated. The error analysis proved the accuracy of the obtained equations. To investigate the quality of each sample according to allowable limit values, based on international standards, real and estimated values were used. Results proved that selecting the most important petrographical parameters for predicting aggregates engineering properties is quite simple and efficient and can be used in the preliminary stages of aggregate evaluations. © 2021
Geomechanics and Geoengineering (17486025)17(1)pp. 188-196
This paper attempts to study the effects of acidic and alkaline waters on the geotechnical properties of a particular type of clay with low plasticity from the northeast areas of Isfahan that have been evaluated with pH values adjusted from 3 to 8. The remoulded specimens were placed in moulds under the influence of acid and alkaline rains with different pH values and years of precipitation. Atterberg limits tests, soil permeability coefficient, California bearing ratio (CBR) test and unconfined compressive strength (UCS) of soil specimens with various pH values were used to evaluate soil mechanical changes relative to soil with neutral acidity. In order to identify internal structural mechanisms of soil before and after artificial raining on the specimens, scanning electron microscopy and pH drainage tests of specimens were performed. The results of the interaction of rain and soil with shifting from neutral values were evaluated over a period of precipitation fluxes from 1 to 20 years. In overall, the more is the acidity or alkalinity of the artificial rain, the more will increase the Atterberg limits and the soil permeability compared to the soil specimens under artificial rain with pH = 7; and the decreasing trend is observed in UCS values and CBR. © 2020 Informa UK Limited, trading as Taylor & Francis Group.
Geotechnical and Geological Engineering (09603182)40(4)pp. 1989-1996
In the present paper, the effect of the depth of the bedrock layer on the land subsidence of the Isfahan plain was studied. The geological bedrock layer was modeled by the results of obtained data from the geotechnical exploratory boreholes, depth of deep wells and geoelectrical in-situ imaging. Regarding the bedrock depth, the case study area was classified into six categories (None, very low, low, medium, high and very high) to show the land subsidence potential zones and to evaluate the risk of the vertical displacement of some critical places. The results indicate that the most of the historical buildings are located in very low-risk and low-risk of the land subsidence areas, however, some places such as Isfahan international airport need land subsidence consideration for any probable destructions due to the vertical displacements. © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
Kohrangi, M.,
Safaei, H.,
Danciu, L.,
Tajmir riahi, H.,
Ajalloeian, R.,
Bazzurro, P. Bulletin of Earthquake Engineering (1570761X)20(8)pp. 3623-3657
We present a seismic source characterization model for the probabilistic seismic hazard assessment (PSHA) of the Isfahan urban area, Iran. We compiled the required datasets including the earthquake catalogue and the geological and seismotectonic structure and faults systems within the study region to delineate and characterize seismic source models. We identified 7 relatively large zones that bound each region with similar seismotectonic characteristics and catalogue completeness periods. These regions were used for calculating the b-value of the Gutenberg–Richter magnitude recurrence relationship and for estimating the maximum magnitude value within each region. The earthquake recurrence parameters were then used to build a spatially varying distributed earthquake rate model using a smoothed kernel. Additionally, based on a fault database developed in this study and on a local expert’s opinion supported by tenable constraints about their slip velocity, a fault-based model is also created. We further performed sets of sensitivity analyses to find stable estimates of the ground motion intensity and to define alternative branches for both the seismogenic source and ground motion prediction models. Site amplification is considered based on a Vs30 map for Isfahan compiled within this study. The alternative source and ground motion prediction models considered in the logic tree are then implemented in the software OpenQuake to generate hazard maps and uniform hazard spectra for return periods of interest. Finally, we provide a detailed comparison of these PSHA outcomes with both those presented in the 2014 Earthquake Model of Middle East (EMME14) and with the national seismic design spectrum to further discuss the discrepancies between hazard estimates from site-specific and regional PSHA studies. © 2022, The Author(s), under exclusive licence to Springer Nature B.V.
Kalantar hormozi, M.J.,
Jorkesh, Z.,
Ajalloeian, R.,
Mortazavi gelsefidi, S.A. Journal of Transportation Engineering Part B: Pavements (25735438)147(2)
The use of construction and demolition (C&D) waste in road construction has been an important and challenging issue in recent years. In this research, geotechnical characteristics of recycled combined construction and demolition waste (RCCDW) at Fooladshahr (located in the Isfahan province, Iran) are studied to determine whether they are an appropriate candidate in road base and subbase. Laboratory tests including sieving, soundness, Los-Angeles (LA) abrasion test, compaction, and California bearing ratio (CBR) are among the tests performed on these materials. The tests were carried out on two types of samples, namely, RCCDW and natural standard aggregates for road base and subbase layers. In Iran, often, no separation is made on C&D wastes such as concrete crumbs and brick lumps. To the best of the authors' knowledge, the majority of the previous studies have been conducted on different percentages of concrete crumb and brick crumb or a combination of both. In comparison, the present study examines almost all types of construction and demolition wastes in place. The obtained results show that after initial recycling and resizing, residues have several remarkable characteristics for use in the base and subbase layers. Although their compressive properties and CBR number were less than the standard limits, they were improved by cement stabilization and became suitable for these road layers. The results show that the maximum dry density of without-cement wastes after stabilization with 12 percent cement (by weight), increased from 1.83 to 2.10 g/cm3, and their CBR value increased from 65.8% to 88.6%. © 2021 American Society of Civil Engineers.
Journal of Adhesion Science and Technology (15685616)35(23)pp. 2664-2683
Enhancement of the mechanical characteristics of ceramic fiber-reinforced soil samples by attaching nanosilica particles to the fiber surface has not yet been fully investigated. The present study took the novel approach of coating the ceramic fibers with nanosilica particles to improve the interfacial interaction of the fiber matrix. The results of direct shear and California bearing ratio (CBR) tests on treated soil specimens and the effects of ceramic fiber content, fiber length and nanosilica content on the mechanical behavior of silty sand are presented. The results showed that the addition of ceramic fibers to the silty sand significantly increased the shear strength and shear strain at the maximum shear stress. The dilative behavior of the soil specimens was found to decrease with the addition of ceramic fibers. The reinforced specimens with a ceramic fiber content of 1.5% and fiber length of 6 mm exhibited the highest peak shear strength. The effects of ceramic fiber content on the internal friction angle and cohesion of the reinforced specimens were dependent on the fiber length. The maximum CBR occurred at a fiber length of 18 mm. The addition of nanosilica noticeably increased the cohesion and slightly increased the internal friction angle. The improvements in the mechanical behavior of the soil after the addition of nanosilica could be attributed to its pozzolanic reaction. The addition of 1% nanosilica increased the influence of the ceramic fiber on the shear strength. In most cases, the addition of nanosilica had a negative effect on increasing the CBR of fiber-reinforced specimens. © 2021 Informa UK Limited, trading as Taylor & Francis Group.
2025 29th International Computer Conference, Computer Society of Iran, CSICC 2025pp. 489-508
Large quantities of waste are produced in various industries and domestic applications, most of which cannot be landfilled because of environmental issues. The researcher’s efforts to produce a binder from aluminosilicate-containing wastes led to the developing of a new generation of binders called alkali-activated materials (AAMs). These cementitious aluminosilicate gels are produced by activating reactive low-calcium aluminosilicate precursors at near ambient temperatures (25-80°C), usually by an intense alkaline solution followed by mixing and curing. AAMs possess beneficial engineering properties in a range of cement-like applications, thus rendering them suitable for various applications, including radioactive waste and toxic containment stabilization, binders for special applications of concretes, fiber-reinforced composites, water, and wastewater treatment, biotechnologies, and many others. This chapter aims to discuss various niche applications where AAMs demonstrate the potential for sustainable concrete and industrial waste management. © 2022 Elsevier Ltd All rights reserved.
Geomechanics and Engineering (20926219)25(3)pp. 253-266
In this paper, we discuss a mathematical method for determining the return energy of the wave from the sample and comparing it with the mechanical energy consumed to change the dimension of the sample in the triaxial test of the rock. We represent a method to determine the mechanical energy and then we provide how to calculate the return energy of the wave. However, the static energy and pulse return energy will show higher amounts with axial pressure increase. Three types of clastic sedimentary rocks including sandstone, pyroclastic rock, and argillitic tuff were selected. The sandstone showed the highest strength, Young’s modulus and ultrasonic P and S waves’ velocities versus others in the triaxial test. Also, from the received P wavelet, the calculated pulse wave returning energy indicated the best correlation between axial stress compared to wave velocities in all specimens. The fact that the return energy decreases or increases is related to increasing lateral stress and depends on the geological characteristics of the rock. This method can be used to determine the stresses on the rock as well as its in-situ modulus in projects that are located at high depths of the earth. © 2021 Techno-Press, Ltd.
International Journal of Hydrology Science and Technology (20427808)10(5)pp. 504-513
Various equations have been developed for assessing the hydraulic conductivity (K) based on particle size distribution. Since the percentages of fine and coarse particles in a sediment significantly influence its permeability, values of K obtained using these empirical equations are erroneous. In this research, a new and applicable equation has been advised which is based on the percentages of fine and large particles in the sample. The following relationship obtained from multiple linear regressions between values of K and corresponding particle size data: K = 0.0419 (Fk)2 – 0.1478 (Fk) + 1.5629, FK = 30Pg(2) – 3PS(0.1) + 3.2. The validity of this new presented equation has been controlled with eight new samples. Calculated values of K using this equation yield relative errors of 5% to 10% which fall in range of allowable errors. Copyright © 2020 Inderscience Enterprises Ltd.
Geotechnical and Geological Engineering (09603182)38(3)pp. 2835-2844
The experimental work described in this paper was carried out in order to discover about the effects of petrographic characteristics on the ultrasonic pulse velocity and dynamic elastic constants of granitic rocks. For this, petrographic characteristics include the mean mineral grain size (MGS) and ratio of Quartz to Feldspar (Qz/Fl), ultrasonic pulse velocity include the P-wave (Vp) and S-wave velocity (Vs), and dynamic elastic constants include the elastic modulus (E) and Poisson’s ratio (ν) of ten different granitic rock were determined. By data analysis, correlations between Vp, Vs, E and ν with MGS and Qz/Fl were developed. It is concluded that the MGS and Qz/Fl have significant effects on the Vp, Vs, E and ν. Moreover, the results showed that MGS and Qz/Fl are in good accuracy for estimating the Vp, Vs and E, while there are no meaningful correlations between ν with MGS and Qz/Fl. © 2020, Springer Nature Switzerland AG.
Arabian Journal of Geosciences (discontinued) (18667538)13(4)
Rate of penetration of a tunnel boring machine (TBM) in a rock environment is generally a key parameter for the successful accomplishment of a tunneling project. Tunneling time is one of the factors that determine the tunneling method (blast or mechanical work). In traditional method, tunneling time depends on the progression function of blast cycle, while in mechanized tunneling method the required time for boring is determined by advance rate and consequently penetration rate. The advance rate is a function of penetration rate of TBM, which is the ratio of the length of boring part of the tunnel to the excavated time of the same part. Penetration rate, on the other hand, is a function of lithology and geomechanical properties of the rock and also the boring machine. So far, many efforts have been made to develop a method to predict the penetration rate (TBM) of the machine. Among these methods are empirical models, particularly NTH model, including models that can be used to predict the penetration rate. In this study, statistical analysis was used to obtain importance of parameters involved in penetration rate and compare the performance of neural networks with other mathematical models based on the principles of probability. In addition, the artificial neural network (ANN) was compared with models of Innaurato and NTH, which indicates high performance of neural networks in predicting penetration rate compared with the other two models. As a result, neural network was chosen and then proceeded to build the network optimized. © 2020, Saudi Society for Geosciences.
Geotechnical and Geological Engineering (09603182)38(3)pp. 3253-3270
Determining the engineering characteristics of rocks is one of the most important challenges in designing construction projects. The triaxial rock testing is one of the most common tests to determine rock engineering properties. In this paper, dynamic properties of a pyroclastic rock specimen have been investigated using multiple ultrasonic tests during rock loading in the servo-controlled triaxial machine. In order to determine these properties, the velocity of P and S waves and the return energy of these waves at different axial and lateral stresses on a rock specimen were evaluated. The results show that the increase of the axial stress to the rock specimen increases the velocity of these waves and their return energy. However, the effect of increasing lateral stress can only be clearly seen in the return energy of the wave. In addition, the ratio of P to S wave velocities (VP/VS) at different axial and lateral stresses ranges from 1.25 to 1.40 and the ratio of the return energies of these waves is approximately between 1.5 and 2.5. © 2020, Springer Nature Switzerland AG.
Geotechnical and Geological Engineering (09603182)38(1)pp. 297-318
The metropolis of Isfahan that is an important historic and tourist city has faced subsidence in recent decades. The purpose of this study is to evaluate the potential and pattern of progressive subsidence in Isfahan Metropolis, located in the middle part of Iran. For this purpose, geotechnical and hydrogeological studies are conducted. Many samples from the 266 boreholes throughout the study area are studied. Many different tests including grading test, soil type, soil thickness, Atterberg limits, plasticity index, void ratio, and consolidation parameters are done. Also, the fluctuations of groundwater table from 2000 till 2014 were also investigated. Then, the results of the tests were combined with the spatial analysis in the GIS software to determine the critical locations as well as the advancing pattern of progressive subsidence in Isfahan Metropolis. The results revealed that moving from the South-East toward the North-West in the study area, the decline in groundwater head was increased from 4 to 36 m. Based on the results, the most severe subsidence occurred in the western border of the city and was calculated to be about 73 cm over the 14 years period. Additionally, inelastic skeletal specific-storage (Sskv) was calculated for fine-grained sediments in the mentioned time span. According to the interpolation map, the maximum values of the inelastic skeletal specific-storage, as well as the most expected subsidence due to a gradual decline in groundwater head, was occurred in the central part of the city. © 2019, Springer Nature Switzerland AG.
Arabian Journal of Geosciences (discontinued) (18667538)13(12)
Bio-mediated soil improvement has been recently introduced as a novel link between biotechnology and geotechnical engineering. Microbial induced carbonate precipitation (MICP) is one of the most promising bio-mediated methods which have been developed based on biologically driven urea hydrolysis. In the present study, an indigenous bacterium that can be used in MICP is identified in the native soil of Sirjan, Southern Iran. This bacterium, called Acinetobacter calcoaceticus Nima (ACN), was compared with the standard Sporosarcina pasteurii (SP), with respect to their performance in the improvement of the mechanical properties of biologically treated soil samples. During a 40-day period of the experiment, direct shear and shear wave velocity tests were conducted to investigate the influence of the treatments on soil properties. Also, stereo microscope images were used to investigate the precipitation on the inter-particle contacts. It was observed that the bio-mediated techniques can significantly improve the mechanical properties of the soil samples. For instance, while the shear wave velocity of the bacteria-free soil was measured as 175 m/s, SP-treated soil has the shear wave velocity of 526 m/s. This value was even higher for the ACN-treated samples (588 m/s) indicating that the local bacteria performed considerably better than the standard SP when used for the native soil. © 2020, Saudi Society for Geosciences.
Environmental Earth Sciences (18666299)79(13)
In the present study, an experimental investigation was conducted to examine the effect of the size of additives on the improvement of collapsible soils. For this purpose, three collapsible soils with severe collapse potential were selected from Varamin Plain, Iran. The selected soils were then treated in the laboratory by the addition of alumina materials in two sizes of 70 nm (nano-alumina) and 685 nm (micro-alumina) and in different contents to improve their mechanical properties. Soil properties including collapse potential, uniaxial compressive strength, compressive modulus of elasticity, direct tensile strength, and tensile modulus of elasticity were selected as the target parameters for the improvement. These parameters were measured and determined before and after the treatment and the behaviors of treated soils were studied in both compression and tension states. The obtained results indicated that the nanometric and micrometric additives have diverse effects on the performance of the treated soil under compression and tension conditions. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
Geotechnical and Geological Engineering (09603182)38(2)pp. 2169-2186
Most engineering projects are involving carbonate rocks in many countries. These rocks are mainly used for various purposes as construction materials for road pavements, Portland cement concrete, building stone, etc. Two important parameters for these projects are the intact rock strength as uniaxial compressive strength (UCS) and crushed rock strength as aggregate crushing value (ACV). Sometimes it is impossible to obtain suitable samples for these tests. Therefore, predicting models have widely used as alternative methods. Since the rock physical properties affect its strength, these properties have been considered to predict UCS and ACV. The main purpose of this study is the application of simple regression, multiple regressions, i.e., linear and non-linear, and artificial neural networks (ANN) to predict the strength properties of carbonate aggregates. In the present paper, 28 samples of carbonate aggregates are studied. The simple physical experiment including porosity (η), density (r), and water absorption by weight (Wabs), and rock strength experiment including UCS and ACV are carried out. Consequently, the best relationships between carbonate aggregate strength and physical properties are determined. Different statistical techniques are used for evaluating and determining the accuracy of empirical equations. The results of the correlation coefficient and significant level indicate that physical properties have significant correlations with ACV and UCS. Subsequent linear and non-linear regression analyses revealed that Wabs and r are the most valid indirect tests to estimate ACV and UCS, respectively. Also, the results indicated that the ANN model showed higher accuracy for predicting UCS (R2 = 0.92) and ACV (R2 = 0.95) than regression models. © 2020, Springer Nature Switzerland AG.
Construction and Building Materials (09500618)230
Aggregate shape characteristics play an important role in the performance of the aggregate materials. The type of crusher and rock may play an important role in aggregate shape characteristics. The aim of this study is to investigate the effect of two types of crusher on the shape characteristics of different rock aggregate. The shape characteristics of aggregate in term of form, angularity and surface texture were evaluated using measured and visual methods based on international recommendations. Shape characteristics of aggregates were quantified by flatness ratio (F), elongation ratio (E), flat and elongated ratio (FE), shape factor (SF), aspect ratio (AR), sphericity (Sp), Rittenhouse's sphericity (RS), Krumbein's roundness (KR), number of fractured face (NFF), and texture-based BS (TBS). Also, the shape (S), angularity (A), and texture (T) factor in Fourier transform were used. Seven samples which have three rock types, i.e., limestone, marble, and tuff, were crushed by jaw crusher (JC) and horizontal shaft impact (HSI) crusher. Systematic statistical and graphical analyses were used to compare aggregate shape produced from different crushers and rocks. The results indicate that the rock type has important effects on the aggregate texture and crusher type has significant effects on the aggregate form characteristics. The rock aggregates produced with JC are mainly blade and disc form, and smoother surface with lower NFF. However, the effect of crusher type is different according to the rock type that has most affected in marble aggregates. © 2019 Elsevier Ltd
Geotechnical and Geological Engineering (09603182)37(5)pp. 4435-4446
Determination of optimum distance between twin tunnels is very important to reduce the construction’s costs in road or railway projects. When two tunnels are located close together, stress concentration in their space increases and it is possible that plastic zones would be merged. In mining engineering and especially underground mining applications, this zone (the distance between twin tunnels) is called pillar and there are some empirical models to estimate its width. However, these models are not completely suitable for all rock types and different tunnel geometries. In this study, an attempt was made to present a new criterion for the design of twin tunnels. It is based on ground reaction curve and takes width to height ratio (w/h) and shear strain of the pillar (obtained by numerical modeling) into consideration. Strain magnitude observed when normal stress (σ1) in the pillar reaches the value of compressive strength of the rock mass (σcm), denotes the allowable ratio of width to height (w/h) which shows the optimum distance between twin tunnels. Pooneh twin tunnels which located in Iran were selected as a case study. These are road twin tunnels excavated in layers of nine different zones (Arak–Khoramabad Expressway). Results of the suggested method show a good agreement between the pillar dimensions seen in the case study and the present method. Taking all aspects of geomechanical and geometrical characteristics of the tunnels into consideration, it is one of the main advantages of this method. © 2019, Springer Nature Switzerland AG.
Bulletin of Engineering Geology and the Environment (14359537)78(6)pp. 3959-3968
Resistance to degradation is one of the most important aggregate properties for engineering projects involving the use of aggregates. The Los Angeles abrasion loss (LAAL) test is among the common aggregate degradation tests that provide information on the quality of abrasion resistance of aggregates. In this study, the possibility of predicting the LAAL from the common aggregate tests including aggregate crushing value (ACV), aggregate impact value (AIV), density (D), water absorption (WA), porosity (P), uniaxial compressive strength (UCS), and point load index (PLI) was investigated. For this purpose, more than 200 rock aggregate samples, which included the most common types, were used. Statistical analysis was performed followed by developing simple linear and the best nonlinear and multiple regression analysis between LAAL and other common aggregate tests. The validity of the various regression equations was evaluated by multiple R (R, R2, and Adj. R2), analysis of variance (ANOVA), and standard error of the estimate (SEE). Results of the simple regression analyses indicate that ACV with R = 0.887, PLI with R = 0.687, and WA with R = 0.607 have the highest correlation with LAAL. Also, results of LAAL, ACV, and AIV could be converted to each other in different rock aggregate samples. The results of multiple and backward regression analyses showed that LAAL could be estimated using a few important variables such as ACV and P or performing simple physical tests including WA, D, and P (R = 0.905 and R = 0.850, respectively). The results of this research could be used for selecting proper rock aggregates in terms of their abrasion resistance, estimating their LAAL range at the preliminary steps of the project, and also for providing a better understanding of the relationships between LAAL and other aggregate properties. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
Bulletin of Engineering Geology and the Environment (14359537)78(3)pp. 1555-1563
Rock aggregates are the most fundamental material of highway, railroad, and other construction activities. The quality of rock aggregates for a given usage is determined by many different test methods, one of the most important of which is the Los Angeles abrasion (LAA) test as it is used to evaluate the resistance to abrasion and wear of aggregates for such applications as railroad ballast, base course material, and asphalt and concrete aggregates. In this study, the relationship between rock texture and LAA loss was investigated for 26 sources of carbonate aggregates found in Iran which constitute the most commonly quarried crushed rock. Regression analyses were used to determine whether rock texture was a useful predictor of LAA loss. The texture of rock aggregate was quantified by texture coefficient (TC), which can be used to put a value on rock texture with studies carried out on the rock thin section using image analysis. In addition, the effects of textural parameters including area weighting of grains or packing density, grain shape, grain elongation, circularity, and orientation of mineral grains, and also TC on the LAA loss were evaluated. Although the results show that weak relationships exist between textural parameters and LAA loss, a strong relationship exists between TC and LAA loss. The results indicate that many textural parameters, together with TC, can be interpreted as rock texture which influences the LAA loss. Also, the results indicate a strong negative correlation between LAA loss and TC, and can be used to predict LAA loss in practical applications. © 2017, Springer-Verlag GmbH Germany, part of Springer Nature.
Journal of Structural Geology (01918141)121pp. 10-24
Microstructures of three naturally deformed rocksalt samples, from the Deh Kuyeh salt fountain in South Iran, were studied by electron backscatter diffraction to constrain deformation and recrystallization processes. Two samples came from the upper salt fountain glaciers and one from the diapiric stem. Lattice distortion and low-angle boundaries in salt grains have intra-crystalline misorientations described by rotations around low-order crystallographic axes and are inferred to relate to dislocation creep and recovery. Misorientation analysis suggests that both easy and hard slip systems are responsible for grain distortions. Small grains have similar dimensions to subgrains, which we interpret to mean that subgrain rotation recrystallization (SGR) is important. Many boundaries are quite lobate, consistent with grain boundary migration (GBM) also being active. Bulges off of some large grains are related to the host by a tilt or twist boundary suggesting that GBM and SGR interacted to facilitate a bulge nucleation process. Idiomorphic grains occur, particularly in the upper fountain (surface glaciers) samples and are less deformed internally than neighboring grains. The grain and subgrain sizes in the sample from the diapiric stem are smaller than those in the upper salt fountain. Subgrain sizes suggest differential stresses were twice as large (2 MPa) during deformation in the diapiric stem compared to the upper fountain. The diapiric stem sample has greater intragranular distortion compared to the fountain samples. Furthermore, the diapiric stem sample has a continuous grain-boundary hierarchy, suggesting a dominance of SGR, whereas the upper fountain samples have different boundary hierarchy characteristics for boundary misorientations above and below ∼7° suggesting that GBM is limiting the SGR process: grains are consumed by GBM before boundaries with misorientations >7° developed by SGR. The increased importance of GBM relative to SGR in the upper fountain compared to the diapiric stem is consistent with the change in balance of the different recrystallization mechanisms expected as a function of lower stress magnitude in the upper fountain. © 2019
Geotechnical and Geological Engineering (09603182)37(2)pp. 599-614
Micro-fabric features are the main factor in determining the engineering properties of rocks. Engineering properties of sedimentary rocks are mainly influenced by grain shape, elongation, orientation, circularity, packing density, porosity, and matrix content, and all of these parameters are controlled by rock texture or micro-fabric. In this study, the relationships between engineering properties and rock texture have been investigated on carbonate rocks. Also, rock micro-fabric was quantified from the texture coefficient (TC) method which could be used to put a value on rock micro-fabrics with the textural parameters. This research presents a study on the TC of carbonate rocks and the main methods to determine and classify engineering properties. For this purpose, 28 carbonate rock samples which have middle to low strength were studied in different locations in Iran. TC values of samples are determined with microscopic laboratory studies carried out on rock thin sections using image analysis. Also, samples were tested in rock laboratory to determine unit weight (γ d ), porosity (P), water absorption (W ab ), uniaxial compressive strength (UCS), point load index (I s50 ) and slake durability index. Regarding TC concept and previous studies, there is some shortage in TC and tried to solve them named corrected TC (CTC). The correlation coefficient (R), coefficients of determination (R 2 ), standard error of the estimate and analysis of variance were used to evaluate the relationships between CTC and each engineering properties. Also, the correlation between TC, CTC and engineering properties of samples are highlighted. Results indicate that all engineering properties of carbonate rocks are mainly influenced by CTC. In addition, CTC had different effects on each engineering properties of samples. Overall, when CTC value is increased, the most of the engineering properties of samples are enhanced. Some engineering properties of samples such as UCS proved a close correlation to CTC, R 2 = 0.92. Also, CTC classification is offered based on the engineering classification of samples. As a result, CTC can be used for evaluating and classifying the engineering properties of carbonate rocks in practical applications. © 2018, Springer Nature Switzerland AG.
Journal of Rock Mechanics and Geotechnical Engineering (25890417)11(1)pp. 121-134
Aggregate degradation (AD) is one of the major reasons accounting for failure of aggregate materials, and the mechanical degradation of aggregate materials can be determined by different test methods. This process basically requires many aggregate samples and special instruments, and thus is time-consuming. The main purpose of this research is to evaluate the possibility of estimating the AD characteristics using rock strength tests and to investigate the relationships between AD properties and rock strength tests. For understanding the relationships, two common rock strength tests are employed, i.e. unconfined compressive strength (UCS) and point load index (PLI) tests. In the tests, the AD properties of 40 kinds of carbonate aggregates sampled from Iran were studied. The AD properties were determined by Los Angeles abrasion value (LAAV), aggregate impact value (AIV) and aggregate crushing value (ACV). Also, the samples are classified according to the strength and rock types, and the effect of this classification is investigated based on the relationship between rock strengths and AD properties. The results indicate that the PLI is better than UCS for evaluation of AD properties. Among rock strength tests, PLI has a closer relationship with AIV (R 2 = 0.832). Also, UCS has relative larger effects on the ACV (R 2 = 0.812) under the same loading condition. The weakest correlation occurs between LAAV and UCS (R 2 = 0.679). In view of the rational AD properties in the predictive procedure, it is possible to predict AD properties based on the strength tests and rock types. The results also show that the prediction of AD properties using rock strength test based on rock types yields better correlations than that using unclassified samples. The classification based on rock types can extrapolate the different relationships of AD prediction from rock strength tests. The results in this context could be used for preliminarily selecting proper rock aggregates with a limit of allowable AD tests for practical applications by PLI. © 2018 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences
Geomicrobiology Journal (01490451)36(7)pp. 581-590
Many types of researches have been carried out on sandy soils to improve the fertility through bacteria. In this regard, after measuring the activity of urease enzymes in urea bacterial sediments, calcium carbonate was applied in Sirjan soil (southeast of Iran), and the native bacteria of this soil were isolated. The strains of these microorganisms, because of the Come and aridity in the region and the severity of the environmental conditions in the area, have a greater resistance to chemical and physical factors and are compatible with the environment of this region. In this study, we tried to use two types of soil bacteria: one is Sporosaercina pasturii, many researchers have been working on this bacterium and the effects of soil improvement, and another is the native bacterium found in Sirjan soil (Acinetobacter calcoaceticus strain Nima). Thirty samples were taken in the same conditions and experiments to evaluate the use of native bacteria of Sirjan in soil remediation by direct shear testing, seismic electronic microscopy, and microscopic scanning (SEM) were performed on the samples. The treatment period for this study was 28 days. The results showed that the angle of internal friction increased for the treated A. calcoaceticus Nima (42%) and S. paturii (39%) compared to untreated samples. Also, adhesion between particles increased by 14.5 times for A. calcoaceticus Nima and 13.5 times for S. paturii. Finally, shear strength for soil treatment increased by4.6 times for A. calcoaceticus Nima and 3.9 times for S. pasturii. The use of indigenous strains in the natural environment due to the adaptation of strains to environmental conditions can increase the production of bio-cementation. It is, therefore, possible to use native bacteria for biologically improved soil as an appropriate alternative rather than traditional methods due to environmental problems. © 2019 Informa UK Limited, trading as Taylor & Francis Group.
Construction and Building Materials (09500618)221pp. 84-98
The replacement of new binders with traditional ones such as lime and cement has caught the eye of researchers in recent decades. The majority of researchers rely on the use of environmentally friendly binders that produce less carbon footprint in the production process. Geopolymer, and more generally, Alkali-Activated Materials (AAMs) are among these binders which can potentially offer an efficient alternative to traditional binders. On the other hand, waste storage generated from quarry and mining industry such as coal gangue has a high risk of environmental pollution. Since most of them contain a lot of silica and alumina, they can be a promising alternative/substance as a precursor in AAMs generation. This paper, thus, reviews the literature on using industrial wastes such as coal gangue and waste glass as precursors for producing AAMs. © 2019
Civil Engineering and Environmental Systems (10286608)36(2-4)pp. 172-198
On 12th November 2017, an earthquake with a magnitude of 7.3 Richter scale in the town of Sarpol-e Zahab took place that caused lots of human casualties and devastation. After the incident, issues related to the probability of an earthquake with equal intensity and extents of similar building destruction were raised in Kermanshah city. Therefore, a seismic microzonation map of Kermanshah city has been prepared based on the geotechnical, geological, and geophysical data, and the data were analysed using Fuzzy analytic hierarchy process (AHP). In the next step, the vulnerability analysis of city buildings was carried out based on the ground-shaking map, vulnerability curves, and statistical data regarding the buildings. The results of the vulnerability rate of residential buildings indicate that 80% of residential buildings would be exposed to vulnerability from low to moderate. However, other buildings would suffer 2% fully destruction (D1), 7% very high destruction (D2) and 11% high destruction (D3), respectively. Finally, according to the obtained results, the proposed model is verified with the help of the data and observations from the Sarpol-e Zahab earthquake, which reveals that the model is in good agreement with the actual earthquake data. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.
International Journal of Rock Mechanics and Mining Sciences (13651609)110pp. 19-27
The mechanical characteristics of salt rock are investigated using uniaxial compression tests and creep tests in a salt diapir located in the south of Iran. To investigate how the microstructure evolution of salt rock due to creep test affects the stress-strain behavior, the crept samples were again tested at a constant displacement rate. The test results showed that the axial peak stress, axial peak strain, and modulus of elasticity gradually increase with increasing strain rate. The stress-strain curves were typical for a ductile material characterized by moderate strain hardening. The creep strain and creep rate increased with increasing axial stress. The Burgers viscoelastic creep model agreed quite well with the experimental creep data. The microstructure observations indicated that grain-boundary cracking and grain boundary sliding were the dominant deformation mechanisms. Under the uniaxial compression test, the crept samples showed a slightly higher modulus of elasticity compared to the intact salt samples. Finally, it seems that free dislocations increased during the creep test led to strain hardening of salt samples through the uniaxial compression test. © 2018 Elsevier Ltd
2025 29th International Computer Conference, Computer Society of Iran, CSICC 2025
Water content in fine-grained sedimentary rocks is an important consideration in many engineering projects. It has been well establish that water content of these rocks can significantly changes most aspects of physical and mechanical properties. This paper presents the effect of water content on the mechanical behavior of three different types of fine-grained sedimentary rocks, clayshale, mudshale and mudstone from different locations. Many samples were tested at a wide range of water contents varying from oven-dried to saturated condition. A general equation was developed for this type of fine-grained sedimentary rocks that may be used for predicting uniaxial compressive strength from the available information on water content. © 2018 ISRM International Symposium 2000, IS 2000. All rights reserved.
Scientific Review Engineering and Environmental Sciences (25437496)26(3)pp. 317-325
For determination of the in-situ deformation modulus of rock mass at Bakhtiari Dam site, located in south-west of Iran, plate jacking tests (PJT) and dilatometer tests (DLT) carried out during the geotechnical investigations. In this study, the results of PJTs and DLTs were compared. This comparison involves 89 vertical and horizontal PJTs and 83 DLTs carried out in 6 rock units of Sarvak formation. Although, both PJTs and DLTs in the Bakhtiari Dam site were performed in same geological and geotechnical conditions, but there are not sufficient side by side data to make a paired two samples correlation. Therefore, the mean of in-situ data was compared at each rock unit. Besides Mann-Whitney U tests were performed to compare in-situ test results. The comparison shows that the deformation modulus measured by both methods has no significant differences. However, in low quality rock masses the moduli measured by the use of DLTs were greater than the modulus measured by PJTs. Conversely, in high quality rock masses the results of PJTs were greater than DLT's.
Bulletin of Engineering Geology and the Environment (14359537)76(3)pp. 1117-1128
The effect of water salinity on the geotechnical properties of a CL soil and mechanical properties of a quartz sandstone has been studied using samples from the Ajichay project, located in the northwest of Iran. The purpose of this investigation is to investigate the feasibility of using saline water in processing the clay core of earthen dams in this area. One-dimensional consolidation, swelling, and uniaxial compressive strength tests were performed on the soil with distilled, half-saline, and saline water. To evaluate the effect of water salinity on the sandstones placed in the abutments of the dams, the slake durability index and uniaxial compressive strength were investigated. Results indicated that the compressibility index decreased, hydraulic conductivity decreased, and uniaxial compressive strength of the soil increased with increasing water salinity. The soil swelling percent with all three waters was less than 1 % after 24 h. However, swelling percent increased by 23 % with saline water and decreased by 32 % with half-saline water. Some damage in the rock texture such as disaggregation, weathering, and corrosion of the feldspars along with the dissolution of carbonate cement was observed in thin sections after 6 months of immersion in saline water. The strength of the sandstones exposed to saline water for 5 months decreased by between 5 and 13 %. © 2016, Springer-Verlag Berlin Heidelberg.
Geotechnical and Geological Engineering (09603182)35(2)pp. 747-763
One of the most important steps in designing underground structures is the evaluation of ground conditions in terms of squeezing potential and behavior of the geological structures. Generally, constructing a tunnel in the squeezing condition is a very slow and difficult task. Therefore, recognition and evaluation of the squeezing potential is very important in selecting a suitable excavation method and support, especially in weak rocks. This research is concerned with the assessment of squeezing potential along tunnel T4 of water conveyance system from Azad dam to Ravansar plain with the length of 11,380 m, located between Kurdistan and Kermanshah provinces, west of Iran. This tunnel is in an almost NS direction and flows through the contact zone of Iran and Arabic plates. According to the engineering geological investigations, the squeezing potential has been recognized as the most important difficulty in the excavation of tunnel T4. This conclusion can be explained by the several indicators including lithology, high disintegration of rock masses, alteration of rocks on the border of Iran and Arabic plates’ contact zone, low rock mass quality, high overburden, and highly jointed rock masses in a shuffle tectonic condition. This paper deals with the engineering geological and geomechanical properties of rock masses. Then, it evaluates squeezing intensity using empirical, semi-empirical, and analytical properties methods. The analysis conducted in these work shows that the tunnel excavation would encounter squeezing problems, which is most severe in region 2 due to the effects of the major young Zagros fault. © 2017, Springer International Publishing Switzerland.
Bulletin of Engineering Geology and the Environment (14359537)76(1)pp. 295-307
The objective of the study described in this paper is to use correlation analysis and multivariate regression analysis for investigating the effect of physical and petrographic characteristics of carbonate rock on its mechanical properties. The cretaceous carbonate samples from boreholes drilled for preliminary investigations in the Koohrang’s third tunnel path, located in the western part of Shahrekord, Iran, were tested to determine the compressive strength, Young’s modulus, dry and saturated unit weight, porosity, and P-wave and S-wave velocity. Then, samples were subjected to petrographic investigation, including size and percentage of grain, matrix type, dolomitization percent, and carbonate percent. The results showed that compressive strength and Young’s modulus values were related to the dolomite percent, grain size, allochem percent, and carbonate percent. Since no single parameter determined strength and Young’s modulus, polynomial prediction equations were developed for estimating mechanical properties. Dunham’s (1962) classification system appeared to show a correlation with mechanical properties determined for the samples, for example, regarding the organic bounds; some textures such as bindstone and bafflestone indicated the lowest strength and Young’s modulus. © 2016, Springer-Verlag Berlin Heidelberg.
Arabian Journal of Geosciences (discontinued) (18667538)8(4)pp. 2069-2079
The geomechanical strength of rock mass plays a key role in planning and design of mining and civil construction projects. The main aim of this study was to develop empirical relations between P wave velocity and physical and mechanical properties such as slake durability index (SDI), uniaxial compressive strength (UCS), modulus of elasticity (E), porosity, water absorption, and density for marly rocks extracted from the southwest Iran. Determination of geomechanical properties in the field as well as laboratory is a time consuming, tedious, and costly process. In this study, an attempt was made to determine these index properties in the laboratory and then each index property was correlated with P wave velocity values. Empirical equations were developed using P wave velocity values to predict SDI, UCS, modulus of elasticity (E), porosity, water absorption, and density where the results were in good agreement. To examine the sensitivity of empirical relationships, Student’s t test was performed to verify the correlation between P wave velocity values and other rock index properties. © 2014, Saudi Society for Geosciences.
Electronic Journal of Geotechnical Engineering (discontinued) (10893032)20(7)pp. 1751-1764
Lack of geological and tectonical knowledge in a region causes hazard in project implementation. There are many examples related to this issue in Iran and the world. Main purpose of this research is to analyze the fractures because of their importance and effect on the implementation of engineering and civil engineering projects such as Khansar-Boien Miyandasht tunnel. For this purpose, the process and density of the fractures and their spatial-geometric position were investigated. Therefore, joints and faults in the Khansar syncline area and the site of Khansar-Boien Miyandasht tunnel were collected, then processed by interpreted in the software such as Stereo32 and Georient. According to the result, a group of joints can be related to pre-tectonics, another one can be related to syn-tectonics(folding and faulting) and some fractures are related to the post-tectonics. Geomechanically, syn-tectonic fractures are extensive in depth and these issues are very important, so it should be considered in implementing the project of Khansar tunnel. Results of the geological engineering study such as, uniaxial strength test, point loading, Schmidt hammer, and ultra-sonic Test were showed high-resistance massive orbitolina limestone, and alternation of shale, limestone, medium- resistance limestone and black slates include low resistance that lead to apply the supports with higher safety factor. Considering the tunnel direction (NNE-SSW), high slope fractures and tunnel tensions, it is possible to create sliding wedges in the left wall and left ceiling of the tunnel. Therefore, tunnel drilling should be performed cautiously by blasting method. © 2015 ejge.
Bulletin of Engineering Geology and the Environment (14359537)74(3)pp. 845-859
Seepage from the body and foundations of dams is one of the most important design parameters highly influenced by permeability. Also, permeability is one of the basic parameters for designing grout curtains, preventing water from escaping from the foundation and avoiding negative seepage pressures in borrow materials used for grouting. In this work, rock mass classification of a rock foundation dam site was carried out using the rock mass rating (RMR) and geological strength index (GSI) systems. This study was mainly conducted to evaluate permeability and groutability at the Nargesi dam site in Iran using secondary permeability index (SPI), joint hydraulic aperture (JHA) and Lugeon tests. Also, the dam foundation was evaluated by pressure tests (WPTs) that indicated the need for a grout curtain below the dam foundation. The rock mass quality of the samples obtained via the SPI in conjunction with the drill core jointing degree acts as a useful reference for ground treatment design. The dam foundation groutability was zoned according to an SPI classification point view. There is no direct relationship between the JHA values and water take in all the sections, but a direct relation is observed in some boreholes. Such a relationship can be attributed to joint characteristics such as persistence, etc. The results of this work revealed, except for a few cases, there is a reasonable correlation between secondary permeability index (SPI) and rock quality designation (RQD) values. Based on these results, a grout type and composition was suggested for construction of the grout curtain. © 2014, Springer-Verlag Berlin Heidelberg.
Geotechnical and Geological Engineering (09603182)32(1)pp. 205-214
Electronic Journal of Geotechnical Engineering (discontinued) (10893032)19(X)pp. 7141-7163
Earthquake hazard zonation is the most important step towards seismic risk assessment and mitigation strategy in densely populated regions. The city of Isfahan, as an important industrial and historical center, is considered among the major economic and cultural poles in Iran. In addition, the existence of seismic evidence and several identified faults emphasizes the need for conducting seismotectonic studies and the development of seismic zonation for this city. In this regard, first, the main faults of the studied area were identified using the digital data from the satellite photos, and their conditions were corroborated by field observations. Then, a probabilistic seismic hazard assessment (PSHA) was conducted using SeisRiskIII software. The first outcome in the current study was preparation of the seismic hazard zoning maps for different hazard levels (according to the Building and construction Iranian Earthquake Code (Std. No. 2800)). Using selected compatible acceleration time histories from past earthquakes, the second was the development of the geotechnical amplification conversion functions corresponding to different soil conditions on bedrock, using SHAKE2000 software, which is based on the application of one-dimensional equivalent linear method (ELM). The results include the distribution maps of average shear wave velocity of the soil, the maximum horizontal acceleration on the ground surface, and the amplification ratio. According to these maps, the PGAs at ground surface and the amplification ratios range between 0.25 g to 0.5 g and 0.9 to 1.9, respectively. © 2014 ejge.
Bulletin of Engineering Geology and the Environment (14359537)73(2)pp. 541-550
Determining the geomechanical parameters of rock masses at dam sites is a very important task. Different methods of determining these parameters have been proposed, depending on various factors such as the study phase, facilities, budget, and the time available. The deformation modulus is an important input parameter in any analysis of rock mass behavior. In the present study, the deformation modulus of the rock mass at the site of the Khersan II double-arch concrete dam was investigated using different field and experimental methods. The Khersan II Dam is located in the southwest of Lordegan, Chaharmahal Bakhtiary Province, Iran. The predominant formation at the site of the dam is the Upper Asmari limestone. The results of in situ tests such as plate load tests (PLTs) were analyzed to determine the deformation modulus, using the ASTM standard, Unal, and ISRM methods. These results were then compared to one another and interpreted. After that, engineering classification parameters such as RMR, GSI, and Q were evaluated at the same site that the PLTs were performed. Finally, the correlations between these classification ratings and the in situ deformation modulus of the rock mass were assessed, and some formulae for determining the deformation modulus of the rock mass at the Khersan II Dam site were derived. The accuracy and credibility of every formula was evaluated. These formulae for estimating the deformation modulus of the rock mass at the Khersan II Dam site were found to be highly accurate compared to other similar formulae. © 2013 Springer-Verlag Berlin Heidelberg.
Rock Mechanics and Rock Engineering (07232632)46(2)pp. 341-357
The focus of this study is the empirical hydromechanical behaviour of the Ostur dam site rock mass. The area surrounding the dam mostly consists of diorite and andesite, with primary fractures and hydrothermal veins. The hydromechanical behaviour of the rocks was determined using 500 water pressure tests at 5-m intervals. The hydrothermal veins and 2,739 discontinuities were studied and mapped along the dam axis. As a result, it was possible to design an optimum grout curtain for the dam axis. The empirical hydromechanical behaviour of the rock was studied to determine water flow and grout pressurised flow during the field tests that were conducted on two representative A-series grouting operation boreholes (one borehole for each abutment). The secondary permeability index (SPI), Lugeon value (LU), rock quality designation (RQD) and cement take (CT) values are presented and compared in this article. It is concluded that permeability and groutability are mostly controlled by the specifications and characteristics of the veins, especially in shallow areas and lower depths. A procedure is proposed based on a comparison of the trends in the RQD-SPI and LU-CT, and it is suggested that the areas with diverging trends require no treatment and that those with converging trends require heavy treatment. Additional complementary studies that were conducted during the construction stage have validated these results. © 2012 Springer-Verlag.
Geomechanics and Geoengineering (17486033)8(2)pp. 86-96
This laboratory project aims to investigate the influence of polyvinyl acetate (PVA) grout injection on sandy soil improvement. In order to make the polymeric material injectable through the soil particles, adhesive polymer is mixed with water in certain weight percentages. Fine grained sand with different dry densities in its loose, medium and dense state, is prepared in a cylindrical mould and subjected to this polymeric grout injection. Unconfined compression tests are conducted on grouted samples after passing their curing period. Results illustrate that increasing the polymer percent in grout leads to significant compressive strength and elastic modulus enhancement. On the other hand, by increasing grout concentration, loose sand demonstrated higher compressive strength and elastic modulus improvement in comparison with medium and dense sand. © 2013 Copyright Taylor and Francis Group, LLC.
Electronic Journal of Geotechnical Engineering (discontinued) (10893032)18pp. 1419-1435
In this research, the effect of water salinity on geotechnical properties of fine grained soil used in Korchay dam core have been studied. This dam is located in Northwestern of Iran. The water samples were obtained from half saline water of Ajichay river and saline water of Korchay branch. In the laboratory, several tests such as Atterberg limits, compaction, consolidation, direct shear and dispersion (pinhole and chemical) were done with distilled, half saline and saline water. Since there are a few percent of active clay minerals in the soil, changes in geotechnical properties of the soil are not considerable. However the results showed the Atterberg limits, compression index and swelling index decrease and consolidation coefficient and shear strength parameters increase as pore water salinity increases. In comparison with distilled water the effect of saline water on consolidation test under high pressures is not consideration. Also the results of dispersion tests showed that there is no dispersion in soil in contact with saline water. © 2013, EJGE.
Electronic Journal of Geotechnical Engineering (discontinued) (10893032)18pp. 1787-1800
Numerical analysis methods have been using in engineering projects for a long time, but using of these methods for seepage analysis of rock mass isn't that much old. UDEC has the capability to perform the analysis of fluid flow through the fractures of a system of impermeable blocks. A fully coupled mechanical-hydraulic analysis is performed, in which fracture conductivity is dependent on mechanical deformation and, conversely, joint water pressures affect the mechanical computations. It has been tried to evaluate the seepage through the karstic limestone foundation of Behesht-Abad dam, Iran. In order to perform this research, geological data during a study phase in Behesht-Abad dam site was firstly gathered, and then different methods have been used to calculate the engineering properties of rock mass. Then the structural model of dam foundation based on the geological data constructed and various water heads were applied on the model. Thereafter fluid flow from each point beneath the dam is available. © 2013, EJGE.
Geotechnical and Geological Engineering (09603182)31(4)pp. 1369-1392
This paper describes the results of the engineering geological investigations and geotechnical studies performed in the Nargesi dam site. The dam foundation located on the sedimentary rocks of Neogen period. To conduct this study, the steps including field and laboratory investigations, surface discontinuity surveying, drilled borehole data, and permeability were performed on dam foundation. Besides, the evaluation of the dam foundation was carried out by water pressure tests, which indicate the necessity of creating a grout curtain below the dam foundation. The permeability and groutability characteristics of the Nargesi dam foundation are significantly affected by geology of the site. The rock mass properties of the test section obtained from secondary permeability index (SPI) completed with the degree of jointing of the drill core acts as a useful reference for ground treatment design. Here, the performed laboratory tests were as: determination of density, moisture percent, porosity percent, water absorption, uniaxial compressive strength, Point-load strength index (Is50), p-wave velocity (Cp), s-wave velocity (Cs), deformability, and triaxial tests. The rock mass properties and classifications of the damsite is assessed using rock mass rating, the rock quality (Q), and the geological strength index classification systems. The strength and modulus elasticity of rock masses were determined through the equations proposed by different researchers. According to the findings of this work, except for some cases, there is a reasonable correlation between SPI and rock quality designation values. Based on these results, grout type and composition was suggested for the design of grout curtain. © 2013 Springer Science+Business Media Dordrecht.
Australian Journal of Basic and Applied Sciences (19918178)6(1)pp. 165-172
Quaternary deposits which cover about a half of country area are counted suitable places for building, water security and agriculture. In spite of studying different characteristics of these deposits, the recognition dispute of engineering geological characteristics of these deposits has not found its position yet. To show the distribution and local relationship of different investigated characteristics such as surface and subsurface soil and soil texture and compaction in the area and geotechnical parameters analysis, it has been used to prepare an initial map including geological maps and liquefaction susceptibility zoning map, and at last with summation of investigated characteristics, it has been made an applied engineering geological map for the East of Isfahan. This is a multipurpose, complete and medium - scale map, in which it has been brought the parameters such as subsurface stratigraphy, groundwater depth, liquefaction susceptibility, inflation potential, spread of fill soil, confronting depth to sand layers and a lot of another parameters. The final result of this research is more recognition of engineering geological of Isfahan area, to identify engineering geological hazards and giving the ways to solve these problems.
Electronic Journal of Geotechnical Engineering (discontinued) (10893032)17pp. 2777-2793
The dam body and foundation seepage is one of the important points in design parameters. This index is related to the permeability. Therefore permeability is one of the basic parameter in design grout curtain, prevent water escape from foundation and avoid negative seepage pressure in borrow materials, so grouting is used. Jamishan rockfill dam with clay core is located in northeast of Kermanshah on the Jamishan River that is one of the branches Karkheh river. The dam foundation located on the schist conglomerate and schist limestone. The main aim of this study is determination of permeability dam site based on calculation hydraulic aperture of joint, secondary permeability index (SPI) and lugeon value. The permeability of dam site cannot estimate alone with Rock Quality Designation (RQD) and lugeon values because in the zones with similar lugeon value may frequency and aperture of joint is deferent. So, frequency and aperture of joint was calculated and analysed in dam site. Type of cement for grouting operation, grouting pressure and grouting curtain was designed and recommended with considering data this. © 2012 ejge.
Electronic Journal of Geotechnical Engineering (discontinued) (10893032)17pp. 2633-2644
This paper describes the results of the engineering geological investigations and geotechnical studies carried out in the Cheshmeh-Asheq dam site. This study is based on field and laboratory investigations, surface discontinuity surveying, drilled borehole data and permeability and groutability of dam foundation. The present studies include the evaluation of the dam foundation by water pressure tests (WPT). The water pressure tests indicate the necessity to provide a grout curtain below the dam foundation. The rock mass quality of the test section obtained from secondary permeability index (SPI) completed with the degree of jointing of the drill core acts as a useful reference for ground treatment design. The rock mass qualities and classifications of the dam site is assigned using the rock mass rating (RMR) and the geological strength index (GSI) classification systems. Results of the studies indicate that except of some cases, there is a reasonable correlation between SPI and RQD values. According to these results, type and composition of grout is suggested for construction of the grout curtain. © 2012 ejge.
Electronic Journal of Geotechnical Engineering (discontinued) (10893032)17pp. 1701-1712
Gukan water convey tunnel is located in west of Isfahan province, central Iran. Tunnel length has been predicted to reach about 22 km. The main function of the tunnel is to convey the water from Dez River to Zayanderod River. Main rock formations in this route include limestone, marly limestone and marl. This paper deals with the study of the limestone behavior which is called Jahrom formation. This formation is encountered in the entrance and the middle of the tunnel. In present research, this formation has been classified using different rock classification such as RMR, Q, and others. Then, rock mass characteristics have been deduced from RMR classification. Finally, it is possible to select suitable support system for circular tunnel of 4m diameter, which estimated by using different proposed methods. © 2012 ejge.
Rock Mechanics and Rock Engineering (07232632)43(3)pp. 305-320
The results of geotechnical explorations, engineering geological investigation (including laboratory and in situ tests) and field observations have been used, along with borehole logging charts, to obtain the rock mass geotechnical data. Based on the data, the rock mass along the Sabzkuh water conveyance tunnel route was classified by rock mass rating (RMR), Q-system (Q), rock mass index (RMi) and geological strength index (GSI) (3 methods). A new series of correlations were established between the systems based on the data collected from the study area. These relationships were then compared with those reported in the literature, and two new relations were recommended. The classifications were utilized to calculate mechanical properties (rock mass strength and deformation modulus) of the rock mass along the tunnel according to available empirical relations, and to distinguish the upperbound and lower-bound relations. © Springer-Verlag 2009.
The Bazoft dam diversion tunnel with length of 450 m and diameter of 9 m is to be excavated in left abutment of Bazoft dam and the currently under study. The lithology mostly comprises of jointed Asmari and Jahrum limestones. The tunnel passes the AS2 zone of Asmari formation belongs to dolomitic limestones of Miocene age. The rock mass discontinuities orientations were studied by a field survey and a statistical analysis. Also the borehole logs and outcrop surveys were used to determine the basic characteristics of the discontinuities. The rock mass surrounding the tunnel is classified using the Q, RMR and GSI methods. The engineering properties and temporary tunnel support systems were determined based on the methods. A series of 3D analytical (stress-strength method) and numerical continuum (FEM) stability analyses were conducted for the rock mass surrounding excavation face based on the excavation scheme proposed by the empirical method based on RMR for supported and unsupported tunnel. Based on the analyses, there is no need for intense support installation. For verification and to determine the influence area of the face, the longitudinal displacement profile values were extracted, drawn and compared with the available literature. © 2010 International Society for Rock Mechanics. All rights reserved.
Journal of Applied Sciences (discontinued) (18125654)10(18)pp. 2027-2033
The direct shear test measures shear strength parameters of soils and other particulate materials. In this study the effects of box size on the strength parameters of soil is studied in Isfahan city area. The soil samples are classified as SC according to the unified soil classification system. The samples were well graded with dry density ranges in the between 1.67 and 1.82 g cm-3. The tests on the shear strength properties of SC soils were carried out by using large, medium and small scale direct shear equipment with shear box dimensions of 60, 100 and 300 mm. The undistributed samples, having almost the same properties, were tested in three square shear boxes of varying sizes. Forty five sets (each set with three samples) of direct shear tests at a constant rate of 1 mm min-1 were performed to study the influence size of the shear boxes and soil density on the strength parameters. The results show the effect of scale on the test. The large and medium scale direct shear produces a higher cohesion and lower friction angle compared with the results of the small-scale direct shear test. The tests indicate that the friction angle and cohesion increase when soil density in each of the three boxes increases. Therefore, these observations suggest that strength parameters are controlled by the scaling effect and physical properties of the soil. The present study also shows the relationship between the shear strength parameters of small and large scale direct shear tests. © 2010 Asian Network for Scientific Information.
American Journal of Applied Sciences (discontinued) (15469239)6(6)pp. 1235-1241
Problem statement: The dam body and foundation seepage is one of the important points in design parameters. This index is related to the permeability. There fore permeability is one of the basic parameter in design grout curtain, prevent water escape from foundation and avoid negative seepage pressure in borrow materials, so grouting is used. Grouting means injected materials like cement or chemical materials under pressure to rock or soil layers. Approach: Purpose of grouting is treatment fractures, fissures, increase strength and decrease seepage. Grout curtain is used for sealing beneath dam body and other structure to obtain above aspects. Results: The present research dealing to study the geotechnical characteristics and conditions of two damsites (Kavar and Sheshpir dam) regarding to their permeability and groutability. Permeability in rock mass is controlled by jointing and their characteristics. The Kavar dam may be constructed on Gareh Aghaj river. This site is located in 40 km southwest of Fars province, Iran. The river flow direction is parallel to the local syncline axis. The main geological features of damsite are faults, fractures and gypsum lenses that they may lead to water escape from reservoir. The rocks in the right abutment of the dam are heavily crushed with low strength. Therefore it is expected that water escape from this zone and some parts of dam axis may happen. This is approved from boreholes logs analysis and Water Pressure Tests (WPT). The other dam which called Sheshpir is located in west of Shiraz, Iran. Regarding to structural geology of this site, two large anticlines are extended in general direction of Zagros mountain range (northeastsouthwest). The geology index features are karstic and jointed rock with faults. In general, regarding the grout-curtain design for each case, it is necessary to evaluate the volume of grout and injection system. Because of complexity of local structural geology especially rock foundation, it is difficult to estimate above-mentioned parameters. Conclusion/Recommendations: Therefore, through a number of WPT in both sites, the Permeability and hydro fracture tests results were used in the foundation for the design of the grouting program. using SPI rock classification systems, it is possible to identify the karstic features of the formation and the relationships between the permeability and groutability. This method that first expressed by foyo identify the special classification for grouting. In this system use results of Water Pressure Test (WPT) and Rock Quality Design (RQD) simultaneously. With the help of these two parameters rock class and grout complex is identified. © 2009 Science Publications.
Landslides (16125118)6(2)pp. 101-109
The Siruyeh landslide occurred at the eastern side of the Siruyeh valley, 22 km west of Semirom city, south of Esfahān on 25th March, 2005 with large dimensions (2,400 m long, 450 m wide with total area of 1 km2). The sliding mass blocked the Siruyeh River making a 35-m-high natural dam and 6-acre lake 570,000 m3 in volume that poses a potential threat for the area. The landslide occurred in soil and intensely weathered marls of the Tarbur and Kashkan Formations (upper Cretaceous-Paleocene age). The overall comparison and interpretation of the gathered evidence from satellite images, field trips, and laboratory tests show that the most important factors involved in triggering the Siruyeh landslide in order of importance are heavy precipitation and snow melt and intense concentration of faults and fractures as well as weathered and weak lithology. © 2009 Springer-Verlag.
Dams are constructed to control the surface runoff. One of the important points involved in grouting operation and cut off curtain design is the geological and hydrogeological investigation of the site and evaluation of its groutability. The commonly method used for determination of permeability coefficient is water pressure test (WPT). The test includes measurement of water pressure (P) and discharge (Q) pumped in the drilled boreholes and its graphical representation as (P-Q) diagrams which can be interpreted to give rock mass hydromechanical behaviour. Based on the test designation, in Ostur dam site, 400 water pressure tests were conducted and analyzed. Results of these tests are used to determine the type of hydrogeomechanical behaviour. In the other hand, the test grouting was also conducted in continuation of the (WPT) operation and the results have shown that the bedrock of this dam is impermeable, with very low groutability potential. However, the shallow part of rock mass is partly affected due to weathering. The type of flow in these parts is identified as turbulent. From the other side, the rock mass is also intersected in deep parts by hydrothermal veins. The flow type in these parts is different from the shallow parts. © ISRM International Symposium - 5th Asian Rock Mechanics Symposium 2008, ARMS 2008. All rights reserved.
2025 29th International Computer Conference, Computer Society of Iran, CSICC 2025pp. 185-189
The swelling behavior of marls is a complex phenomenon. In saturated state, these materials present considerable volume changes resulting in swelling and mobilizing high swelling pressures. The behavior of swelling in rocks is controlled by numerous factors acting jointly and resulting in an effect whose main agent is frequently hard to identify. The design of tunnels in swelled grounds is a difficult task. Some problems are generally met for characterization and testing marls and for prediction the response of tunnel excavation and support loading. In this research we investigate the swelling behavior of marls and analyze the effect of their physical and mechanical properties on swelling considering to a case study. Our studied samples are red and green marls that are taken from Kohrang III water conveyance tunnel project, located in Chaharmahal Province in Iran (fig. 1). Physical and mechanical properties of these rocks were determined of some laboratory tests on samples which were derived from horizontal boreholes in digged parts of the tunnel. Our results showed the role of texture, structure and mineralogy in swelling potential in marls. The comparison between these two kinds of marls indicates that the major factor in swelling of marls is their hydration. Unloading has no impact on their swelling in comparison with their mineralogical composition and the type of clay minerals. Also the results indicate that red marls are more compacted with higher resistance. Finally experimental results confirmed that compaction degree has no direct relation on swelling potential. © ISRM International Symposium - 5th Asian Rock Mechanics Symposium 2008, ARMS 2008. All rights reserved.
American Journal of Applied Sciences (discontinued) (15469239)4(8)pp. 547-553
The main mineralogical/lithological composition of the Varzaneh aeolian sands is sedimentary and igneous lithics. The minor one is metamorphic lithics and mineral grains (such as quartz, feldspar and heavy mineral grains) respectively. The origin of the sedimentary lithics (mainly carbonates) mostly is from sedimentary rocks exposed in the west and the southwest of the study area. These rocks belong to Cretaceous and Jurassic outcrops. The origin of the igneous lithic grains chiefly belongs to Tertiary highlands, located to the north and the northeast of the study area. The main origin of the metamorphic lithic grains is from the mountain ranges located in the north-western and the western part of the drainage basin of the Zayandeh river. Texture of the aeolian sand grains is similar to the Zayandeh river sediments. Concentration of the aeolian sands at the west of the Zayandeh river delta, variation of their mineralogical/lithological composition from north to south, and textural characterizations of sand grains indicate that the water laid sediments of the Zayandeh river, widespread to the north of the aeolian sands, are the main supply of the aeolian sands and sediments deposited by the two ephemeral streams in the south and the southwest of the sand dunes are minor one. © 2007 Science Publications.
Carbonates and Evaporites (08912556)19(1)pp. 67-74
The Gavkhoni Playa Lake is located to the southeast of Esfahan, Iran. It is surrounded by the Varzaneh aeolian sand field to the west and alluvial/fluvial sediments to all other directions. It is typical of the few permanent lakes within closed drainage basins in Iran. The properties of intermittent fine-grained and coarse-grained siliciclastic and finally fine-grained evaporite sediments suggest that the basin was influenced repeatedly by wet and dry periods. During periods of flooding, it had been a shallow permanent lake. With increasing aridity, the middle of the lake became increasingly restricted and shallower which resulted in the formation of a salt pan, contributing to the nature of the lake brine. Due to the enclosed nature of the lake system, the water chemistry of Gavkhoni Playa Lake is dominated by sodium and chloride ions but shows wide variations in composition and concentration through time and location. The percentage of Na+(1,012 to 10,3040 ppm), Cl(4,118 to 19,9365 ppm), Mg2+ (360 to 25,691 ppm), and K+(78 to 3,570 ppm) is highest toward the south and at a minimum in the north. Calcium content, ranging from 160 to 3,480 ppm, appears highest in the north. The percentage of strontium (5 to 292 ppm) with the highest value to the north, is extremely low in comparison to other elements. Sulfate is another abundant anion in the brines with the highest content of 22,051 ppm. Bicarbonate is a minor anion ranging from 73 to 450 ppm with the highest values to the north and west. The concentration of sulfate and bicarbonate does not change regularly in the brines from north to south, nor does it vary seasonally. The chemical analysis of the brine shows that it becomes progressively depleted in carbonate and sulfates from the margins to the center of the lake. It ultimately became a Na+, (Mg2+), Cl-brine type in the northern section and a Na+, Mg2+, Cl-brine type in the central part of the lake. After complete desiccation, the mineral assemblage exhibited halite, camallite, bischofite, and tachyhydrite in abundance.
International Journal of Rock Mechanics and Mining Sciences (13651609)41(SUPPL. 1)
There are various structural and geological stratigraphies in study area. The main lithology includes the shale, marl, limestone and dolomite that belong to the Cambrian to upper Cretaceous besides Quaternary deposits. To identify the engineering and geotechnical characteristics of the rock mass along the tunnel route, the results of laboratory and in situ tests, geophysical explorations (geoelectrical methods), field observations and borehole logging charts have been used. The well-known rock mass classification systems for tunnelling purposes (RMR, GSI and Q-system) have been used. Using the GSI classification system for rock mass, the modified Hock- Brown criterion parameters of the rock mass for typical section were determined. The RMR was used to determine the required support for the entire length of tunnel. Also the Q system was used to compare the required support from Q system with the RMR system. Finally rock-support interaction analysis was conducted for a typical cross section of the tunnel. Using the above empirical and analytical methods, the required supports were compared for a typical section. © 2004 Elsevier Ltd.
Engineering Geology (00137952)68(3-4)pp. 225-236
Site investigation and evaluation of properties of soil or rock are important aspects of geotechnical design. Determination of the ground stiffness is one of the important parameters in geotechnical engineering. Since the measurement of shear modulus is very sensitive to soil disturbance, especially for sand, determination of the stiffness of soil in the field is more reliable than in laboratory tests on sampled specimens. Measurement of shear modulus is one of the most common applications of self-boring pressuremeter testing. As an in situ device, the pressuremeter provides a unique method for assessing directly the in situ shear modulus of a soil. This paper describes a laboratory study of silica sand stiffness, which varies with stress level and strain amplitude. The results show that the elastic shear modulus value is mainly dependent on the value of the mean effective stress and relative density. © 2002 Elsevier Science B.V. All rights reserved.
Bulletin of Engineering Geology and the Environment (14359537)59(3)pp. 195-199
Mudrocks exhibit a variation in compressive strength when the direction of the plane of weakness is varied with respect to the direction of the principal stresses. Uniaxial compression tests were performed on two anisotropic mudrocks (siltshale and mudshale). The sample laminations were at orientation angles of 0, 15, 30, 45, 60, 75 and 90° relative to the direction of loading. The anisotropy strength ratio (the ratio of the maximum compressive strength to the minimum strength) over the full range of the lamination orientations was determined. The results of the uniaxial compressive strength tests were compared with the strength anisotropy index ratio [IS(50)] determined from the point load strength tests. The difference between the anisotropy ratios from the individual point load test results and from the uniaxial compressive test results indicates the difficulty of determining the anisotropy from point load tests.
Geotechnique (17517656)48(5)pp. 621-636
The pressuremeter test has proved to be a useful tool for geotechnical engineers to determine the in situ properties of soils. However, results indicate that the strength values derived from pressuremeter tests are often quite different from those obtained from good laboratory tests and other in situ tests. It is believed that a major part of this disagreement may be due to the influence of pressuremeter geometry. This is because, in most analyses, the pressuremeter is assumed to be infinitely long, although commercial pressuremeters are of finite length. Therefore, it is necessary to investigate the possible effect of the finite pressuremeter length on soil parameters derived from the tests. A two-dimensional axisymmetric finite-element analysis was used to simulate pressuremeter tests. It was found that the finite pressuremeter length has a significant effect on derived soil properties. Experimental studies on the effect of a finite pressuremeter length reported in the literature are not sufficiently comprehensive to reach a definite conclusion about the effect of pressuremeter geometry on derived soil properties. In the present study, therefore, a large number of pressuremeter tests with four different length/ diameter ratios (L/D = 5, 10, 15, 20) were conducted in a 1 m × 1 m calibration chamber located at the university of Newcastle, Australia. Based on the results of those laboratory pressuremeter tests, experimental correlations are presented which can be readily used in practice to account for the effect of pressuremeter geometry on the derived soil properties.
