Evaluation of foundation types' effects on the performance of structures located on old landslides

Construction in areas with active faults or construction of important structures on soils having already experienced old landslides is among the cases with a high potential risk for human lives and finances. In this study, a numerical investigation will be applied to study the effects of an old landslide in the city of Tabriz on the geotechnical characteristics of the site, where the marl soil in the site has been severely disturbed due to landslides, and various joints have been created in the soil and gypsum layers. To this aim, a random finite element procedure using the Monte-Carlo simulation will be employed to analyze the slope stability of the site, and the worst distribution of the shear strength parameters will be chosen for further investigations. The random finite element analysis will be done using the OPTUM G۲ software. It is shown that the geotechnical properties of the assumed site have experienced a considerable distortion, which Corresponds with the geotechnical in-situ observations. The achieved results appear that applying the raft foundation for the expected building improves static and seismic behavior. For static loading conditions, the existing strip foundation has inadequate capacity to bear settlements and un-allowable settlements will happen. However, the raft foundation makes settlements ۳ times lower than the permissiblevalues. The pattern of the settlements for these two foundations is also distinctive; whereas the strip footing leads to non-uniform settlements, building with raft foundation will involve uniform deformation. Seismic and static analyses show that the application of raft foundation has more efficiency in the static condition than seismic loading situations.

Keywords:

landslides , Monte-Carlo simulation , geotechnical properties , OPTUM G۲