Probabilistic Analysis of Piping in Habdat Earthen Embankment Using Monte Carlo and Subset Simulation: A Case Study

In recent years, reliability analysis has become an integral part of any design work of engineering structures to establish its success by considering the various uncertainties involved. The sources of uncertainties are generally the variation of material properties throughout the domain of interest, loadings, estimation procedure, mechanical and manual errors, etc. In this paper, the probabilistic analysis of Habdat earthen embankment has been performed using both Monte Carlo (MCS) and Subset Simulation (SS) techniques. The local seepage velocity is considered to carry out piping analysis considering hydraulic permeability (k) of soil as a random variable in an MS-Excel sheet. The performance of horizontal filter at the base of embankment in the prevention of piping is also investigated. It is found that the filter suppresses the phreatic line and provides safety against piping as it helps to increase the flow length of the water and reduce the exit gradient (i(e)). It is further noticed that SS can investigate low probability of failure events up to 0.001 with a smaller number of samples compared to direct MCS. This fact indicates that SS performs better than direct MCS in estimating risk for important engineering structures designed for low P-f values.