Analysis of Crack Reliability for Gravity Dams Based on FEM and Response Surface Method

The allowance crack length is the distance from the dam heel to centerline of drainage holes. The real crack length is varied with the hydraulic pressure acted on the dam and material mechanical properties. Nonlinear FEM analysis is used to obtain the real crack length, and the Mohr-Coulomb criterion with lower tensile strength is used to simulate the cracking and yielding state on the interface between dam and foundation. The limit state equation of crack reliability for gravity dams is established with the computation length and the allowance length. The hydraulic pressure, parameters for Mohr-Coulomb criterion, and mechanical parameters for dam and foundation are taken as random variables. The linear response surface method is used to obtain the iterative result of the reliability and the orthogonal test design method is used to reduce the number of finite element analysis. The LongTan RCC gravity dam is taken as an example and the crack reliability is given.