Factors Affecting the Sliding Stability of a Gravity Retaining Wall

Abstract

This study investigates the sliding stability of gravity retaining walls by integrating the spatial variability of soil properties into a probabilistic framework. Unlike traditional deterministic methods, which assume fixed soil parameters and rely solely on safety factors, this approach employs Monte Carlo simulations in MATLAB to account for the inherent uncertainties in soil behavior. The analysis focuses on how variations in key geotechnical parameters, specifically the internal friction angle of the backfill, the cohesion of the foundation soil, the unit weight of the backfill, and the foundation friction angle, affect the probability of failure for different levels of safety factors. The results show that the spatial variability of the backfill’s internal friction angle and the cohesion of the foundation soil plays a critical role in sliding failure. When a commonly used safety factor of 1.5 is applied, the corresponding failure probabilities often exceed the acceptable threshold of 10⁻⁴. Conversely, the variability in backfill unit weight and foundation friction angle has minimal influence on failure risk. These findings underscore the limitations of conventional design approaches and demonstrate the necessity of incorporating probabilistic analyses to achieve more reliable and robust designs. The study supports the adoption of reliability-based methods for safer and more resilient retaining wall structures under uncertainty.