Slope reliability analysis considering spatially variable shear strength parameters using a non-intrusive stochastic finite element method

• A non-intrusive stochastic finite element method is developed.
• Slope reliability with spatially varying shear strength parameters is studied.
• The proposed method is much more efficient than the LHS method.
• Ignoring spatial variability may underestimate the probability of slope failure.
• Variation of probability of slope failure highly depends on factor of safety.

This paper proposes a non-intrusive stochastic finite element method for slope reliability analysis considering spatially variable shear strength parameters. The two-dimensional spatial variation in the shear strength parameters is modeled by cross-correlated non-Gaussian random fields, which are discretized by the Karhunen–Loève expansion. The procedure for a non-intrusive stochastic finite element method is presented. Two illustrative examples are investigated to demonstrate the capacity and validity of the proposed method. The proposed non-intrusive stochastic finite element method does not require the user to modify existing deterministic finite element codes, which provides a practical tool for analyzing slope reliability problems that require complex finite element analysis. It can also produce satisfactory results for low failure risk corresponding to most practical cases. The non-intrusive stochastic finite element method can efficiently evaluate the slope reliability considering spatially variable shear strength parameters, which is much more efficient than the Latin hypercube sampling (LHS) method. Ignoring spatial variability of shear strength parameters will result in unconservative estimates of the probability of slope failure if the coefficients of variation of the shear strength parameters exceed a critical value or the factor of slope safety is relatively low. The critical coefficient of variation of shear strength parameters increases with the factor of slope safety.