SLOPING GROUND LIQUEFACTION- CASE HISTORY BASED ANALYSIS

Abstract

Liquefaction is one of the most interesting, controversial and complex phenomenon in geotechnical engineering. The devastating earthquakes of Prince William Sound, Alaska, USA and Niigata, Japan in 1964 are considered milestones in the study of liquefaction as the occurrence of liquefaction and its consequences were well-documented and publicized following these events. Because of its engineering importance, liquefaction problems have received a great deal of attention among the geotechnical community and many efforts have been made to clarify the basic mechanism and various aspects of the problems associated with liquefaction. Liquefaction can occur in both level and sloping ground e.g. dam embankments. This study focused on sloping ground liquefaction and discussed ten reasonably documented case histories failed due to earthquake and/or static liquefaction to validate the relationship of strength ratio and corrected penetration resistance proposed by Olson. In stability analysis soil properties and static/dynamic loading is given and factor of safety is calculated by using Geo studio SLOPE/W software. Strength ratio used for the stability analysis have been taken from the graph proposed by Olson. The strength ratio varies from 0.16 to 0.24 for the 10 new flow failure case histories analyzed. The variation in strength ratio is related to corrected penetration resistance. The results of the flow failure case histories analyzed in this study are well within the boundary curves proposed by Olson. A relationship is proposed by using seven static liquefaction case histories to check the displacement of soil mass after failure with respect to the difference between yield and liquefied shear strengths. It is hypothesized that less the difference between yield and liquefied shear strengths less will be the distance covered by failed soil mass and vice versa.