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Quarterly Journal of Engineering Geology and Hydrogeology (14709236) 55(1)
The Sivaki Dam is an earth dam that is located near Yasuj city, 5.3 km NW of Sepidar village. During excavations at the dam construction site, the high potential of water seepage from the foundation and its abutments has been proven. Some cavities and dissolution have been observed on both sides of the dam, suggesting the possibility of karstification at greater depths. Most of the rocks cropping out in the study area comprise Asmari Limestone. These rock masses, despite their medium– high strength, have provided unfavourable conditions in terms of permeability and weathering. In this study, the foundation and both abutments of the dam were evaluated and analysed to determine the permeability and groutability characteristics. To achieve this goal, the engineering characteristics of the rock mass of the construction site were examined by performing rock mass rating (RMR) and geological strength index (GSI) classifications. The Lugeon test, secondary permeability index (SPI), rock quality designation (RQD) and monitoring hydraulic flows were used for this purpose. According to the results of this study, for abutments of the dam and in the case of alluvial substrates, a grout curtain and cutoff wall, respectively, are the best and most compatible methods available. © 2021 The Author(s).
Waste Management and Research (0734242X) 39(2)pp. 325-350
The present study evaluated and selected the best location among susceptible landfill sites in Rudbar County using 27 criteria, as the maximum effective criteria, in the decision-making process. The emergence and comparison between the two methods of fuzzy and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) with an engineering–geological approach have been conducted to obtain the best results. In this regard, inappropriate regions for landfill construction have been restricted after the conflation of two maps based on the restriction criteria. Then, the direction of prevailing winds and proper area for landfill construction was investigated for a 20-year perspective, and the regions that had more than 35-hectare area and were not located in the direction of the prevailing winds have been identified as responsive sites for landfill construction. Ultimately, selected susceptible regions were prioritized separately based on the TOPSIS and fuzzy methods. To ascertain the accuracy of the results and the reality of the resulted models, complementary field studies, geotechnical digging, and engineering–geological experiments have been used as verification parameters. According to the results of the verification, the fuzzy model having maximum matches with the verified data has been suggested for prioritizing susceptible regions. © The Author(s) 2020.
The presented article provides an experimental classification for South Pars marls (SPM), southwest of Iran, using the Schmidt hammer rebound index, marl geological classes, and SPM geo-engineering characteristics. In this regard, 45 samples of marls (rock) are selected on the studied site and tested by geotechnical in-situ and laboratory tests such as Schmidt hammer, uniaxial compressive strength (UCS), laboratory direct-shear (LDS) to estimate the geo-engineering characteristics of SPM. These specimens are categorised by Pettijohn's marl classification in 3 main groups (concluded argillaceous lime, calcareous marl, and marlstone) and established the geologic class and geo-engineering properties as well as Schmidt hammer rebound index. In the meantime, the geologic classes and the Schmidt index show the logic classification. Thus, this work attempted to prepare the experimental classification based on Pettijohn's marl classification and Schmidt rebound index for SPM. According to geotechnical experiments results, the Schmidt index shows 3 main group variations like Pettijohn's marl classification. • This method can be used to prepare the geologic status based on the Schmidt rebound index. • This method can be useful for detailed decryption of geo-engineering characteristics of different type of marls in the studied area. • This method can be used as a quick link for marl geologic status and geo-engineering features. © 2021
Modeling Earth Systems and Environment (23636203) 7(1)pp. 159-168
The strategy applied in this study is fuzzy logic based decision-making system to achieve a rapid way to assess block-toppling failure instability in discontinuous rock slopes as justified by kinematic analysis that are applied to real cases. Referring to fuzzy logic based decision-making; the best option was selected from multiple fuzzy variables through performing a comparison and by obtaining the fastest solution for approximation. The expert system offers a capable fuzzy application for engineering judgment to be utilised in geotechnical decision making for engineering design. Kinematic analysis is currently used for the stability assessment of all types of toppling failures which provides the ‘occurrence possibility’ and is not capable of describing the stability conditions (degree of occurrences) in discontinuous rock slopes. Application of fuzzy logic complements kinematic analyses through giving a more accurate stability assessment. This study offers a complementary method for block-toppling failure instability assessment in discontinuous rock slopes based on artificial intelligence and a fuzzy expert decision-making system. © 2020, Springer Nature Switzerland AG.
Azarafza, M. ,
Akgün, H. ,
Ghazifard, A. ,
Asghari-kaljahi e., E. ,
Rahnamarad, J. ,
Derakhshani, R. International Journal of Digital Earth (17538955) 14(12)pp. 1918-1941
Slope stability is one of the most important topics of engineering geology with a background of more than 300 years. So far, various stability assessment techniques have been developed which include a range of simple evaluations, planar failure, limit state criteria, limit equilibrium analysis, numerical methods, hybrid and high-order approaches which are implemented in two-dimensional (2D) and three-dimensional (3D) space. In the meantime, limit equilibrium methods due to their simplicity, short analysis time, coupled with probabilistic and statistics functions to estimate the safety factor (F.S), probable slip surface, application on different failure mechanisms, and varied geological conditions has been received special attention from researchers. The presented paper provides a review to limit equilibrium methods used for discontinuous rock slope stability analyses with different failure mechanisms of natural and cut slopes. The article attempted to provide a systematic review for rock slope stability analysis outlook based on limit equilibrium approaches. © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
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.
Computers and Geotechnics (0266352X) 124
This study introduces a simplified semi-distinct element algorithm for discontinuous rock slopes under toppling instability assessment based on block theory. The presented algorithm is developed to investigate block, flexural and block-flexural types of toppling failures which have been coded in the Python high-level programming language. In order to investigate toppling instabilities for different modes, the three modelling steps, namely, geometrical, behavioural and mechanical simulations were conducted to appoint high-order calculation trending loops. These loops were based on the analytical description of modified second-order reliability method with first-order efficiency to determine the factor of safety values for discontinuous rock slopes. Each type of toppling failure was described based on main assumptions that were modified by geometric qualifications such as the analytical procedure, single block slip, and the Voronoi diagram algorithm for the stability analysis of the three different failure types. According to the stability assessment results of the studied slopes which were verified by the distinct numerical method via UDEC software, it has been clarified that the results obtained from the algorithm and the numerical analysis were in an appropriate trend. The used algorithm is superior in pinpointing the critical sliding zones, safety factor estimation and progressive failure analyses as compared to the numerical analyses. Moreover, the block theory based algorithm has higher processing capability and speed with respect to the numerical method. © 2020 Elsevier Ltd
Bulletin of Engineering Geology and the Environment (14359537) 78(5)pp. 3371-3383
Block geometry is commonly the most important feature determining the behaviour of a rock mass and directly controls the structural instability in underground openings or surface cuttings. Various methods are used to estimate block geometry and to perform a block survey, and these are standardly divided into empirical-based methods (e.g. spot mapping, linear mapping, areal mapping) and computer-based methods (e.g. laser scanning, image processing, digital image mapping). Empirical approaches are associated with effective features as well as with a number of errors; however, the latter can be covered by artificial intelligence (AI) techniques. The combination of image processing and areal mapping have led to geometric block estimation in two-dimensional (2D) and three-dimensional (3D) spaces; these approaches can be widely used in stability analysis, dimension stone extraction, excavations, open pit mining design and the delineation of blasting patterns for dimension stone extraction. Therefore, the application of an approach that allows both the modelling and production of rock blocks based on their actual status with qualified accuracy and speed are both worthwhile and necessary. In this study, to estimate the shape and block dimension utilized, we used the algorithm based on the AI image processing technique for rock mass structural detection and for rock block definition in 2D and 3D space obtained with the Mathematica software package. The algorithm, by categorizing the discontinuities in two groups (opened and closed), which represents the main and the secondary discontinuities, can identify the emplacement and shape of rock blocks. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
Geomechanics and Engineering (20926219) 19(5)pp. 393-405
This paper evaluates the geotechnical and geo-engineering properties of the South Pars Zone (SPZ) marls in Assalouyeh, Iran. These marly beds mostly belong to the Aghajari and Mishan formations which entail the gray, cream, black, green, dark red and pink types. Marls can be observed as rock (soft rock) or soil. Marlstone outcrops show a relatively rapid change to soils in the presence of weathering. To geotechnically characterise the marls, field and laboratory experiments such as particle-size distribution, hydrometer, Atterberg limits, uniaxial compression, laboratory direct-shear, durability and carbonate content tests have been performed on soil and rock samples to investigate the physico-mechanical properties and behaviour of the SPZ marls in order to establish empirical relations between the geo-engineering features of the marls. Based on the experiments conducted on marly soils, the USCS classes of the marls is CL to CH which has a LL ranging from 32 to 57% and PL ranging from 18 to 27%. Mineralogical analyses of the samples revealed that the major clay minerals of the marls belong to the smectite or illite groups with low to moderate swelling activities. The geomechanical investigations revealed that the SPZ marls are classified as argillaceous lime, calcareous marl and marlstone (based on the carbonate content) which show variations in the geomechanical properties (i.e., with a cohesion ranging from 97 to 320 kPa and a friction angle ranging from 16 to 35 degrees). The results of the durability tests revealed that the degradation potential showed a wide variation from none to fully disintegrated. According to the results of the experiments, the studied marls have been classified as calcareous marl, marlstone and argillaceous lime due to the variations in the carbonate and clay contents. The results have shown that an increase in the carbonate content leads to a decrease in the degradation potential and an increase in the density and strength parameters such as durability and compressive strength. A comparison of the empirical relationships obtained from the regression analyses with similar studies revealed that the results obtained herein are reasonably reliable. © 2019 Techno-Press, Ltd.
Environmental Earth Sciences (18666299) 78(10)
One of the most crucial parts of the waste management is to choose an appropriate method for site selection. Selecting an appropriate site for sanitary landfill is a complicated task regarding consideration of spatial and non-spatial factors such as social, economic, technical, and environmental issues which requires an applicable method that should be able to make a good relationship between aforementioned conditions and prediction of further situations. In line with that issue, the present study has used fuzzy logic spatial modeling to select the best location and prioritize prone areas for constructing the landfills in a region with harsh morphological situation and sensitive environment such as Rudbar city. This study was conducted in three stages. At the first stage, after combining the maps based on restriction parameters, improper areas have been eliminated. At the second stage, by considering the direction of dominant wind and proper area for construction of landfill in a 20-year perspective in understudied area with more than 35 hectares and not located in the direction of dominant wind, had been identified as suitable areas for constructing landfills. At the last stage, the selected areas in previous stage have been evaluated by fuzzy method and they have been compared with each other based on the considered criteria. Eventually, the prioritization of prone areas has been evaluated based on qualitative classification and they were divided into 5 classes as: excellent, very good, good, average, and weak. Based on the obtained results, 0.41% of the region was classified as weak class, 0.89% as average class, 1.07% as good class, 0.70% as very good class, and 0.76% as excellent class in terms of appropriateness for constructing landfill. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
Geotechnical and Geological Engineering (09603182) 36(4)pp. 2021-2035
This study discusses the engineering geological investigations for site selection of Abnahr Damsite, in order to select a suitable site from two alternatives. The alternatives are located on Mehrian River, relatively close to each other. Two alternative axes are located on an alternation of marlstone and limy marlstone. Although the rock types in both axes are the same, the engineering geological investigations revealed that their geomechanical characteristics are somewhat different. Based on these differences, one of the axes is more suitable. In this study, two alternative axes were investigated to determine their geomechanical characteristics including rock mass permeability, rock mass quality, RQD, Alluvium conditions, slope stability, and paleoslides. The suitability of the axes was finally judged based on all obtained characteristics of two alternatives. In order to make a rational decision, the analytical hierarchy process technique was used as a decision making support tool to quantify the subjective and descriptive judgments to subjective values. The results show that use of this type of systematic approach in decision making processes is very useful, especially for dam site selection. © 2018, Springer International Publishing AG, part of Springer Nature.
Environmental Earth Sciences (18666299) 77(24)
This study assesses the landslide susceptibility of the South Pars Special Zone (SPSZ) region that is located in southwest Iran. For this purpose, a combinatorial method containing multi-criteria decision-making, likelihood ratio and fuzzy logic was applied in two levels (regional and local) at three critical zones (northwest, middle and southeast of the project area). The analysis parameters were categorised in seven main triggering factors such as climatology, geomorphology, geology, geo-structure, seismic activity, landslide prone areas and man-made activities which have different classes with multi-agent partnership correlations. Landslide susceptibility maps were prepared for these levels and zones after purified and enriched fuzzy trending runs were performed. According to the results of the risk-ability assessment of the landslide occurrences for SPSZ, the north part of the study area which includes the south edge of the Assalouyeh anticline and the southern part of the Kangan anticline were estimated as high-risk potential areas that were used in landslide hazard mitigation assessment and in land-use planning. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
Journal of Arid Land (16746767) 9(5)pp. 778-789
Based on the data from piezometers, well logs, geophysical surveys and the interferometric synthetic aperture radar (InSAR) technique, this study investigates the main causes of land subsidence in Damaneh City, Iran. The size, openings and direction of fissures were measured by micrometer and compass. The locations of fissures and wall cracks were determined by GPS. The geoelectrical data were used to determine the composition, thickness, depth and shape of lower parts of the aquifer. Groundwater fluctuations were evaluated by available piezometers. The InSAR technique was used to measure land deformation from space and to map the dense changes of surface displacements. The results indicate that the main cause of ground subsidence is the decline of groundwater heads and changes in composition and thickness of compressible lacustrine sediments. The subsidence map obtained from the radar data of ASAR sensor of ENVISAT satellite shows that the subsidence zone is mainly in northern city that is underlain by very thick fine sediments. The subsidence rates from March to December 2005 and from July 2011 to January 2012 are 6.7 and 7.0 cm/a, respectively. The results also show good correlations among the formation of earth features, decline in groundwater head and thickness of fine-grained sediments. We recommend that the groundwater withdrawal for agricultural and industrial sectors should be restricted and urban expansion in the northern part of the city should be constrained. © 2017, Xinjiang Institute of Ecology and Geography, the Chinese Academy of Sciences and Springer-Verlag GmbH Germany.
Taherynia m.h., M.H. ,
Fatemi aghda s.m., S.M.F. ,
Ghazifard, A. ,
Moradi e., Iranian Journal of Science and Technology, Transaction A: Science (10286276) 41(2)pp. 375-381
Withdrawal of oil and gas from reservoirs causes a decrease in pore pressure and an increase in the effective stress which leads to reservoir compaction. Reservoir compaction can be result in surface subsidence through the elastic response of the subsurface layers. To determine the subsidence above a hydrocarbon field, the reservoir compaction must first be calculated, and then, the effect of the reservoir compaction on the surface is modeled. The use of the uniaxial compaction theory is a more customary and accepted method for determining the amount of reservoir compaction induced by pressure depletion. Surface deformation above compacting reservoirs can be efficiently modeled using influence functions. In this paper, Knothe and Geertsma influence functions were used in a simple approach for subsidence modeling of the South Pars gas field. In this approach, we used circular network, called influence network, for determining the whole reservoir compaction effect on the field surface. In addition, the subsidence of the South Pars gas field is modeled using the AEsubs software, and the results are compared to the predicted subsidence by the influence functions. © Shiraz University 2016.
Bulletin of Engineering Geology and the Environment (14359537) 75(3)pp. 1157-1168
Kashan Plain is located in an arid area on the west side of central desert of Iran in north of Isfahan province. In recent decades, increasing population, industrial and agricultural developments in the region that require water withdrawal have resulted in the decline of groundwater and the occurrence of subsidence in this plain. Since 1991, earth fissures that have caused many damages to buildings, farmlands and roads have been observed in many parts of Kashan Plain. The lengths of some of these fissures are more than 2 km long. In this study, after determining the location and direction of fissures, the probable influential causes of earth fissuring were investigated. The results indicated that the main causes of this phenomenon are basically the decline of groundwater head, variation in sediment thickness due to bedrock anomalies and differential vertical compaction. In order to investigate the rate of land subsidence in the Kashan Plain, the Envisat ASAR data from 2003 to 2008 were used. The displacement maps were generated by InSAR time series analysis. The maximum rate of subsidence in this period was determined to be about 3.5 cm/year. © 2016, Springer-Verlag Berlin Heidelberg.
Electronic Journal of Geotechnical Engineering (discontinued) (10893032) 18pp. 2621-2627
The focus of this study is to predict the subsidence of the South Pars gas field at the end of production period. With respect to the notable reservoir thickness, significant pressure drop due to extraction and high areal extent of the South Pars gas field there is a high potential for subsidence to occur in this field. In order to determinate the maximum land subsidence and subsidence profile of the South Pars gas field, at first, the reservoir compaction was estimated based on the thickness of the reservoir, the pressure drop in the reservoir, and the uniaxial compaction coefficient of the reservoir rock and then the effect of the reservoir compaction on the field surface was modelled with use of semi-numerical methods. The compaction of the reservoir at the end of production period was estimated to be about 0.48 m. The subsidence modelling methods predicted that the maximum subsidence will reach about 0.6 m at the end of production period. © 2013, EJGE.
International Journal of Environmental Health Engineering (22779183) 1(8)
Aims: The purpose of this research was to determine the effects of soils contaminated with lead, zinc and cadmium on the high concentration of these metals in the urban air. Materials and Methods: In this regard 63 samples of soil and 18 air samples were taken at sampling grids from various regions of the city. After digestion of samples, the extracted liquids were analyzed by atomic absorption spectroscopy. Results: The concentration of lead, zinc, and cadmium in the soil samples were not higher than international standards, but was two to three times as high in the air as that found in European countries and U.S. Results also showed a correlation between concentration of these metals in the city soils and their increased level in the city air through dust and wind, particularly in the northern parts of the city, whilst no such correlation is found in the southern parts, which could be due to wind blowing dust polluted with these metals from heavy industries located at south‑west of Isfahan. Conclusion: As, at present time, there is a ban on consumption of leaded petrol throughout the city, two main probable sources of lead pollution in the air of the city of Isfahan are dust from contaminated soil and also, presence of a large steelworks industry in the south‑west of Isfahan which is in the direction of south‑west to north‑westerly winds. Copyright: © 2012 Ghazifard A.
International Journal of Environmental Health Engineering (22779183) 1(1)pp. 57-62
Aims: This research was conducted to study the effects of the electrical conductivity (EC) of irrigation water and compost on the Cadmium (Cd) and Zinc (Zn) uptake by sunflower, Helianthus annuus. The transfer of Cd and Zn from soils close to the Zn mine, to the sunflower tissues, and the interactions between the two concerned metals, were also investigated. Materials and Methods: For this purpose, 10% weight/weight from municipal composts was applied to raw soils that were randomly collected from the mine region. Series analyses were also implemented by irrigation water, with EC values in the range of 0, 2, 4, and 6 dS/m. Results: The maximum uptake rate of Cd, with EC levels of 6 dS/m, in plant samples was 4.82 μg/g for the roots, 6.14 μg/g for the stems, and 5.4 μg/g for the leaves; and the maximum uptake of Zn, in plants irrigated with tap water, was 241 μg/g by the roots, 624 μg/g by the stems, and 229 μg/g by the leaves, respectively. Conclusions: Results showed that high EC levels of irrigation water increased Cd accumulation and decreased Zn accumulation in the shoots. The presence of high EC levels in irrigation water negatively affected biomass production by plants. Chlorine ion (Cl-) had a positive influence on Cd accumulation in the harvestable parts of the plant. © 2012 Medknow. All Rights Reserved.
Environmental Earth Sciences (18666299) 62(2)pp. 337-345
The Jandagh-Moalleman road, which crosses the Great Kavir of Iran, was completed in 1999. Less than 1 year after completion, road subsidence problems began. In order to determine the causes of failure, field observations were taken along with surface and subsurface samples from road segments exhibiting typical problems. Laboratory experiments were conducted to determine their physical, chemical, and engineering properties. The results indicate that there are two typical layers in this playa: an upper, hard, salty crust layer composed of up to 46% soluble materials; and a lower, thick, muddy layer which is mostly composed of silt, clay minerals, gypsum, and halite. It was concluded that mineral dissolution of the upper salt crust layer and the sinking of road fill materials into the lower muddy layer, are the main causes of road settlement. An appropriate method to protect the road against the dissolution of its soluble materials is recommended. © 2010 Springer-Verlag.
Applied Clay Science (01691317) 43(2)pp. 248-252
Inward gradient landfills are attractive because the inward flow of groundwater is believed to inhibit outward movement of contaminants. However, clay liners may act as semipermeable membranes and exhibit coupled solute and water flow behavior. Our initial evaluation of the membrane behavior of clays used as liners for inward gradient landfill cells suggests that the situation is not as simple as previously thought. The total volume flux (water plus dissolved solutes) through a clay liner may not always be directed inward during the lifetime of an inward gradient landfill even though an inward-directed hydrostatic head difference is maintained. Thus we recommend that synthetic liners be used at least on the basal portion of inward gradient landfill cells to limit outward coupled flux of the dissolved components of leachate and water and that groundwater monitoring may be more important than previously thought for inward gradient landfills. We also suggest that the membrane behavior of clay liners used at inward gradient landfills be incorporated in the design of the cell. © 2008 Elsevier B.V. All rights reserved.
Environmental Geosciences (10759565) 16(1)pp. 25-39
A large number of potential light nonaqueous-phase liquid (LNAPL) traps exist in poorly sorted sands underlying the buried valley train surfaces in the lower Mississippi River Valley (LMRV). These traps should be considered during site characterization and remediation activities related to spilled nonaqueous-phase liquids and leaking underground storage tanks on the valley train surfaces of the LMRV. These traps have apparent average dimensions of 0.84 by 0.21 km (0.52 by 0.13 mi), with an average closure height of 2.7 m (8.85 ft). The maximum apparent lateral dimensions are 4.19 by 0.69 km (2.6 by 0.42 mi) and the minimum observed lateral dimensions are 0.06 by 0.02 km (0.03 by 0.01 mi). Apparent closure heights range from less than 1 m (3 ft) to an apparent maximum of 7.6 m (24.93 ft). A depth of about 4.3m(14.1 ft)is assumed to be a maximum likely excavation depth for underground storage tank installations in the LMRV. The top stratum thickness in 47 of the 100 borings used to construct cross sections in this study was less than 4.3 m (14.1 ft). Thus, it is likely that underground storage tank installations, for example, have or will breach the top stratum at many sites on the valley train surfaces. In order for spilled LNAPLs from underground storage tank sites to migrate into one of these traps, it is probably necessary that the original excavation breach the low-permeability top stratum and that the water table seasonally fluctuates from below the base of the top stratum to above the base of the top stratum. Copyright © 2009. The American Association of Petroleum Geologists/Division of Environmental.
The Gardaneh Rokh tunnel is being excavated with the length of 1300m it axis striking of N28. The height of tunnel section is 8.6m and its width is 13m. To characteristics of the discontinuities were recorded from 5 outcrops as survey stations. A series of laboratory tests was conducted on the intact rock samples selected from cores taken from two boreholes to get the physical and geomechanical properties. The rock mass along the tunnel enroute was divided into 5 structural zones and were then classified based on the Q and RMR systems. The required support systems were also determined according to the systems. Regarding tunnel stability analysis, the tunnel inlet section as the weakest zone of rock mass located in km 6+300 (structural zone 5) is numerically modelled and analyzed using PLAXIS software with and without support system. The excavation and support installation process was modelled in 3 phases. The results of the numerical modelling show that the crown and sidewalls instabilities are mainly reduced by installation of partial shotcrete support in crown and sidewalls. However, the support installation even in lower sidewalls may not substantially reduce the displacements in invert.
Iranian Journal of Science and Technology, Transaction A: Science (10286276) 31(1)pp. 7-16
During this research, bacteria resistant to metals were evaluated in the soil of Isfahan Province. According to the sampling locations the soils are classified as agricultural soils, non-agricultural soils and sediments of the Zayanderood Riverbank. The bacteria resistant to lead (2 mM), copper (5 mM), cadmium (0.5 mM) and arsenic (5 mM) were identified, and then during later stages, the minimum inhibitory concentration (MIC) for the growth of the bacteria resistant to metals were determined. The dry cellular weight and the metal uptake rate were also defined for the bacteria resistant to metals.
Waste Management and Research (0734242X) 19(3)pp. 257-261
The thermophilic and mesophilic microbiota in compost produced from Esfahan municipal solid waste were examined at different stages of composting process from day zero to 28 days and was conducted in four different seasons. Some of the mesophilic bacteria observed in initial stages of composting process were gram negative Escherichia, Klebsiella, Aeromonas and Alcaligenes, and gram positive Enterococcus and Bacillus species. After 20 days of the composting process lower species diversity of mesophiles (only Bacillus species) were isolated, which was most likely due to the high temperature (60-68°C) condition. Some of the observed thermophilic bacteria at later stages of the process are: Bacillus subtilis, B. polymyxa, B. pumilus, B. sphaericus, and B. licheniformis from thermotolerants, and B. stearothermophilus, B. acidocaldarius, and B. schleglii from thermophiles. Among the mesophilic fungi, at the initial stages of composting process some types of yeasts and molds were isolated, but after day 20 due to high temperature condition (60-68°C), no mesophilic fungi were obtained. On the 15th day of composting the highest diversity of thermo-tolerant fungi such as Cladosporium, Aspergillus, Mucor, Rhizopus, and Absidiae spp. were observed. The results indicated that, in order to obtain a sanitary product in cold seasons, the composting process needs a longer duration and fewer turnings.
