Reliability Analysis of Width-Constrained Piled Slopes Considering Three-Dimensional Spatial Variability of Soil Strength

Stabilization pile is a common measurement to enhance slope stability. Since the deterministic factor of safety cannot reflect the inherent uncertainty and spatial variability of mechanical properties of soil, it is highly desirable to employ a probabilistic analysis for slope reinforced with piles. This paper presents a probabilistic analysis procedure for width-constrained piled slope where the failure pattern and spatial variability of soil are both accounted for under three-dimensional (3D) conditions. A modified discretization kinematic analysis-based mechanism is employed as the determined model. Such a mechanism adopts a novel hybrid strategy to greatly improve the computational efficiency on the basis of the origin discretization mechanism. The e?ective cohesion and friction angle of the soils are modeled as lognormal random fields by using the Karhunen-Loève expansion. The sparse polynomial chaos expansion (SPCE) is used to construct the metamodel to reduce huge computation costs in high dimensional stochastic problems. The failure probabilities, probability density function and other useful reliability results can be provided within limited simulations. Finally, the influences of soil spatial variability, slope geometry and pile parameter on reliability analysis results are conducted. The combination of modified discretization mechanism and SPCE provides a useful tool in probabilistic analysis of piled slope under 3D conditions. The reliability finding is also helpful for piled slope reliability design in practice.

Keywords: pile reinforced slope, three-dimensional reliability analysis, soil spatial variability, kinematic analysis, sparse polynomial chaos expansion