Assessment of the changing of Major Structures Located in Clay Foundation

Stability of major structures is one of the important subjects in the civil engineering. Stability of clay foundation is due to ground water penetration through porous media of the soil. Therefore, water level control and suitable drainage system can be so important to protect the foundation of such structures. Leaching in soils is the important subject in the geotechnical engineering. Lixiviation of soluble salts cause the change of physical properties as unit weight, void ratio, Atterberg Limit, hydraulic conductivity and specific gravity. This study indicated that in result of leaching the soil structure have been porous and removal the soluble salts and part of the fine particle change the dry unit weight, void ratio and hydraulic conductivity. One of the effects of reduction strength in soils is instability slopes that finally cause sliding.In this study, following series of chemical, physical and strength tests, the effect of leaching has been appointed and investigated on the north Iran's clay soils. This study indicates that as a result of leaching the soil structure have become porous and removal the soluble salts and part of the fine particle change the dry unit weight, void ratio, specific gravity and hydraulic conductivity. Also, leaching cause the reduction of mechanical properties and unconfined compressive strength, Elasticity of modulus, Cohesion and friction angle in two condition as drained and un-drained conditions. Finally, using the result of laboratory tests and comparison with the results of a case study using a numerical approach, the effect of leaching in sliding has been investigated

Keywords:

Stability , Soil , Modulus of Elasticity , Leaching , Foundation