Role of soil composition on collapsible behavior of natural and stabilized slopes

In slope stability projects, collapsible behavior is known as one of the main reasons for slope failures. Collapsible soils exhibit considerable strength and stiffness in their dry and natural state. However, they lose strength and settle upon wetting. It is known that the internal soil support provides temporary strength which is derived from a number of sources including, capillary tension and cementing agents. By and large, the behavior of collapsible soils are usually evaluated on their mechanical response. This study uses physico-chemical evaluation to explain the general basic causes for collapsible performance of slopes. Some basic and fundamental aspects and physico-chemical roles of soil pore water characteristics which directly affect the collapsible performance of slopes are presented. It is shown the x-ray diffraction is able to provide some realistic evaluation of the collapsible performance of slopes.