Evaluation of clay layer presence on shallow foundation settlement in dry sand under an earthquake

Seismically, settlement of buildings with shallow foundations lying above dry sand soils has caused severe destruction in recent earthquakes. This study investigated the effect of seismic loads with shallow foundations located above sandy soil containing an intermediate soft clay layer. The impact of a clay layer's existence with different thickness and closeness to the base of foundation when subjected to El Centro earthquake with 6.9 magnitude. This investigation has been carried out with the help of a three-dimensional PLAXIS 3D, which has been used to solve many geotechnical issues. A database was created for the various dynamic and static parameters of soils in seismically active areas of Iran and Iraq and USA. In this research, important factors are recognized, including relative density. Clay layer thickness and proximity to the foundation, the soil relative density the results of this research indicated that shallow foundation settlement increased on the dry sand and decreased with the presence of clay layer thickness and wave propagation in cohesion soil is less than cohesion-less soil. In addition, it was reached that as close as the clay layer to the foundation the settlement increased.