Stability analysis of rock slopes considering strata uncertainty using dual-source surface wave inversion with borehole constraints

Abstract

The stability of rock slopes is mainly controlled by subsurface characteristics, such as soft layers and broken zones. However, determining their locations and associated uncertainties is challenging due to their concealment and complexity. This study proposes a framework for stability analysis of rock slopes, which accounts for strata uncertainty quantified through dual-source surface wave inversion with borehole constraints. The shear wave velocity profiles of the slope were obtained by combining active surface wave and passive microtremor using multichannel analysis of surface waves (MASW) method and microtremor survey method (MSM), respectively. The prior constraints for the inversion were obtained from borehole television and ultrasonic testing. Subsequently, the inverted depths of the interfaces were represented as continuous distributions and fitted to various models. The stability of the slope was then analyzed by incorporating strata uncertainty. The proposed framework was applied to a steep road-cut rock slope located in Shandong Province, China. The results show that the proposed framework effectively detects soft layers and quantifies uncertainties in interface depths for probabilistic stability analysis. The dual-source surface wave inversion provides both sufficient detection depth and high resolution of shallow strata. Incorporating the prior borehole-derived constraints, the accuracy and speed of the dual-source surface wave inversion have been greatly enhanced. The interface depths can be quantitatively described by normal distributions, which have been selected based on the lowest Akaike Information Criterion (AIC) value. Three soft layers were identified in the presented case, and variations in the thickness of the soft layers influenced the safety factor.