Effect of the Stability of Major Structures Located in Soil Foundation

Stability of the major structures located on soil foundation is one of theimportant subjects in the civil engineering. Stability of clay foundationis due to ground water penetration through porous media of the soil.Therefore, water level control and suitable drainage system can be soimportant to protect the foundation of such structures. Leaching in soilsis the important subject in the geotechnical engineering. Leachingresulted in removal salts of soils and reduction strength and physicalproperties of soils. Lixiviation of soluble salts cause the change ofphysical properties as unit weight, void ratio, Atterberg Limit, hydraulicconductivity and specific gravity. As a result of becoming loose the soilstructure, strength parameters are reduced. One of the effects ofreduction strength in soils is instability slopes that finally causesliding.In this study, following series of chemical, physical and strengthtests, the effect of leaching has been appointed and investigated on thenorth Iran's clay soils. This study indicates that as a result of leachingthe soil structure have become porous and removal the soluble salts andpart of the fine particle change the dry unit weight, void ratio, specificgravity and hydraulic conductivity. Also, leaching cause the reductionof mechanical properties and unconfined compressive strength,Elasticity of modulus, Cohesion and friction angle in two condition asdrained and un-drained conditions. Finally, using the result oflaboratory tests and comparison with the results of a case study using anumerical approach, the effect of leaching in sliding has beeninvestigated.

Keywords:

hydraulic conductivity , Leaching , Soil , Stability , Foundation