Probabilistic seismic passive resistance of hunchback retaining wall considering spatial variability

Abstract

The importance of gravity hunchback retaining wall in supporting a spatially random soil backfill subjected to earthquake is studied using probabilistic analysis. A lower bound finite element limit analysis formulation is used for plastic analysis of homogeneous and heterogeneous soil. The internal friction angle of soil is spatially varied using random field theory and Karhunen-Loéve expansion method. The uncertainty in soil parameter is recorded using Monte-Carlo Simulation method. The seismic waves are simulated using modified pseudo-dynamic approach. The effect of both inertial as well as body force on retaining wall and soil are considered. The behavior of soil at each time interval is studied and the most vulnerable behavior at a particular time is recorded for all cases of probabilistic analysis. The effect of depth of foundation soil is studied and observed that the analysis for a particular case with no foundation soil (i.e., rigid base) may overestimate the magnitude of passive resistance by around 2.3 times as compared to the wall with foundation soil. It is also worth noting that there are some cases of spatial variability where the probability of failure is non-zero due to soil heterogeneity even when the factor of safety is more than 1.5.