Abstract Reliability-based slope stability analysis has great prospect in design but few attempts have been made to study the reliability of rock slopes in three dimensions. In order to evaluate the reliability of 3D rock slopes during the construction period,an abutment slope at the left bank of Jinping I hydropower station was taken as an example. The computational costs for stability analysis of 3D rock slopes are high and the factor of safety can not be explicitly expressed as functions of input parameters when the finite difference based shear strength reduction method is incorporated in slope stability analysis. In this paper,a parametric sensitivity analysis was carried out to reduce the number of random variables and the non-intrusive stochastic finite difference method was proposed for reliability analysis of the 3D rock slope. The effects of the failure of two main reinforcement measures,including the pre-stressed cables and the shear-resistant concrete plugs,on the deformation,stability and reliability of the slope were investigated. The variation of the displacement perpendicular to river flow,the factor of safety and the reliability of the slope during the construction period were also studied. The proposed approach of parametric sensitivity analysis identifies effectively the rank of the sensitivities of different random parameters,which lead to greatly improved efficiency of calculation. The non-intrusive stochastic finite difference method provided an effective way for analyzing the reliability of the practical 3D rock slopes,where a decoupled data interface between a probabilistic analysis module and the software FLAC3D is implemented and the results of the slope stability analysis in the parametric sensitivity analysis are further used in the slope reliability analysis. The jointed measure of stabilization with the pre-stressed cables and the shear-resistant concrete plugs in the left abutment slope at Jinping I is found to be able to effectively control the slope deformation and ensure the slope stability. The disturbances induced by the slope excavation during the construction period are found to have a significant influence on the slope reliability.
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Received: 31 March 2014
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