Efficient 3-D reliability analysis of the 530 m high abutment slope at Jinping I Hydropower Station during construction

• 3-D reliability of 530 m high abutment slope is investigated.
• Effects of reinforcement measures on engineered rock slopes are explored.
• A non-intrusive stochastic finite difference method is proposed.
• A parametric sensitivity analysis is performed to identify significant parameters.

Reliability-based slope stability analysis and design show promise, but few attempts have been made to study the 3-D reliability of high rock slopes. This paper aims to investigate the 3-D reliability of practical rock slopes and to explore the effects of reinforcement measures on slope reliability. A non-intrusive stochastic finite difference method is adopted to perform 3-D reliability analysis of high rock slopes, in which response surface functions are adopted to establish the explicit functions between the factors of safety for multiple slope failure modes and the significant random variables. The left abutment slope at Jinping I Hydropower Station in China is taken as a case study. A parametric sensitivity analysis is carried out to identify the significant uncertain parameters. The effects of two reinforcement measures, namely pre-stressed cables and shear-resistant concrete plugs, on the reliability of the rock slope during construction are highlighted. The results indicate that the 3-D reliability of complex rock slopes can be efficiently evaluated using a non-intrusive stochastic finite difference method. It provides an effective tool for solving 3-D reliability problems of complex rock slopes in practice. The combined support system with pre-stressed cables and three shear-resistant concrete plugs adopted in the Jinping I left abutment slope can effectively restrain the slope deformation and ensure the slope stability during construction. The disturbances induced by the excavation blasting during construction have a significant influence on the engineered slope reliability.