SEISMIC PERFORMANCE OF SLOPES IN PSEUDO-STATICDESIGNS WITH DIFFERENT SAFETY FACTORS

Seismic coefficient values coupled with minimum pseudo-static safety factors are still used for analysis where selection of seismic coefficients relies on expertise and judgment. However, safety factor approach does not give any idea about the deformations and displacements that are expected to occur during earthquake loading. Displacements are mostly evaluated by equations based on yield acceleration of the slope and maximum acceleration of sliding mass. The method based on rigid block gives co-seismic permanent slope deformation when its factor of safety equals 1.0, hence, there is a need to link slope displacements, seismic coefficients and pseudo-static safety factors. This will enable the designers to predict slope displacements based on selected seismic coefficients. In the present paper, slope displacements obtained for different peak ground accelerations and safety factors are used to propose charts linking co-seismic slope displacements (D), seismic coefficients (kh) and pseudo-static safety factors (FS), which are important parameters in pseudo-static approach. This enables the kh values to be chosen based onallowable displacements instead of using judgment and expertise. Results show that kh values for any allowable displacement should be based on anticipated PGA and FS values. Subsequently, slope displacements are utilized in developing a novel displacement-based methodology to select the seismic coefficient which will be used to calculate the pseudo-static safety factor.