Effect of geological conditions on road construction in Jandagh Playa of Iran

Abstract

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.