基于非平稳随机地震动模型的重力坝抗震可靠度分析

Seismic Reliability Analysis of Gravity Dams Based on Non-stationary Random Ground Motion Models

摘要:

基于正交展开的非平稳随机地震动模型，并考虑混凝土材料的非线性和坝体与库水之间的流固耦合，对印度Koyna重力坝进行有限元分析，得到坝顶水平位移和坝颈拉应力，结合概率密度演化方法和等价极值事件的思想，获得丰富的概率信息。这为坝体结构的随机地震反应分析和可靠度研究提供新的途径。

Abstract:

Based on the method of orthogonal expansion and the idea of random variables, the evolutionary power spectrum model of the non-stationary ground motion acceleration process is proposed, and parameter values of the model are determined according to the code. The non-stationary ground motion acceleration process can be represented as a function with a basic random variable, and the set of representative time histories of the non-stationary ground motion acceleration process with complete probability is obtained. To prove the effectiveness of the method, the Koyna gravity dam in India is used as an example to analyze its response and reliability. Considering the nonlinearity of concrete materials and fluid-solid coupling between dams and reservoir water, the finite element analysis is conducted and horizontal displacement of the dam crest and tensile stress of the dam abutment are obtained. It is shown that rich probability information can be obtained by using the probability density evolution method and the thought of equivalent extreme events. This study provides a new approach of random ground motion response analysis and a reliability study of dam structures.