Reliability Coupled Sensitivity Analysis of Water-Front GRS Wall Using Monte Carlo Simulation

Geosynthetic reinforced soil (GRS) walls are so much advantageous that the executor does not hesitate to construct it even on the bank of river/stream or the places where probability of flood hazard is more. GRS wall is a geotechnical structure, liable to uncertainties, flexible in nature, tolerant to settlement, resilient to earthquake, but sensitive to water. The present study identifies the potential failure mode affecting the failure of the system and analyzes the severity of each random variable on the failure modes. Also combining probability of failure (Pf) of each mode with the sensitivity (S) of each random variable extends the concept of the probabilistic risk factor (Rf) for GRS wall subjected to flood hazard. Probability of failure (Pf) is obtained from Monte Carlo simulation by coding the limit equilibrium and tie-wedge method equations in simple excel formula. Sensitivity of each random variable is carried out by F test analysis using one-way ANOVA test. The risk factor determined for each random variable, if implemented in deterministic design as partial safety factor, will provide safety to waterfront GRS wall subjected to inundation and drawdown. It is found that two modes of failure, namely sliding and pullout, are critical and these modes of failure are highly affected by drawdown and scour. The most and only critical factor which is sensitive and having maximum effect on probability of failure is angle of friction of reinforced soil/backfill soil.