Failure analysis of high-concrete gravity dam based on strength reserve factor method

Abstract

Maintaining stability against the sliding of a high-concrete gravity dam built on a rock mass of complex geology is a key problem. In this paper an anisotropic laminar layer element with thickness is used to simulate mechanical deformation properties of weak-bed intercalations at a dam’s foundation as well as a contact friction interface element without thickness to simulate joints and fissures of the rock mass at the dam’s foundation. Nonlinear finite element method (FEM) analysis was used to calculate the resistance to sliding of a high-concrete gravity dam at the dam’s foundation. The strength reserve factor (SRF) method was adopted to simulate progressive failure and possible unstable modes of the dam’s foundation system, and the method for determining the ultimate bearing resistance of this system. The strength analysis method of the connection of the plastic yield zone was used to obtain the ultimate bearing resistance of the dam’s foundation while it was undergoing failure. Finally, nonlinear finite element analysis was performed to find a solution for the sliding of this dam, the high-concrete gravity dam of Xiangjiaba Hydropower Station on Jinshajiang River in Yunnan Province, China, while it was under construction. The calculation shows that the failure of the dam is related to the strength (or weakness) of the silt-laden layer at the dam’s foundation, and the strength reserve factor of final failure was 2.6.