基于NESSUS与ANSYS的地下洞室可靠度分析

Reliability analysis of underground caverns based on NESSUS and ANSYS

提出了基于结构可靠度分析软件NESSUS和有限元分析软件ANSYS的岩土工程可靠度分析方法.首先简要介绍了NESSUS软件的基本功能,其次给出了采用NESSUS和ANSYS软件进行可靠度分析的具体计算步骤,最后以地下洞室变形可靠度问题为例证明了该方法的有效性.结果表明:NESSUS软件和ANSYS软件有机结合能够有效地分析岩土工程可靠度问题,尤其适用于需要采用有限元分析的复杂岩土结构物可靠度.该方法可靠度分析与确定性有限元分析过程互不耦合,不需要修改确定性有限元分析代码,可以方便地调用现有有限元计算程序,从而为解决复杂岩土工程可靠度问题提供了一条有效的途径.敏感性分析结果表明弹性模量对洞室变形可靠度影响最大,容重次之,粘聚力和内摩擦角影响可以忽略不计.弹性模量变异性对洞室变形可靠度影响非常显著,相比之下,容重变异性对洞室变形失效概率影响较小.

This study aims to propose a geotechnical reliability analysis method by combining the softwares NESSUS with ANSYS. Firstly, the basic performances of the software NESSUS are introduced; then the computational procedures combining the softwares NESSUS with ANSYS are presented in detail. An ex- ample of the deformation reliability analysis of the underground rock cavern is presented to demonstrate the validity and capability of the proposed method. The results indicate that the proposed method can provide an effective way for complex geotechnical reliability problems, especially for these involving complex finite element analyses. Where the reliability analysis and deterministic finite element analysis are completely de- coupled; and the existing finite element codes are directly called without modification. The sensitivity anal- ysis results indicate that the elastic modulus is the most significant random variable, followed by unit weight, whereas the cohesion and internal friction angle have a negligible influence on the reliability re- sults. In addition, the variability in the elastic modulus has a significant influence on the reliability results of the underground cavern, whereas the variability in unit weight almost has little influence on them.