研究了基于Copula函数的抗剪强度参数联合分布模型对岩土结构物系统可靠度的影响规律,揭示了抗剪强度参数间相关结构对岩土结构物系统可靠度影响的过程。介绍了不完备概率信息条件下基于Copula函数的抗剪强度参数联合分布模型构造方法,提出了Copula理论框架下岩土结构物系统失效概率计算的蒙特卡罗模拟方法,以典型岩土结构物如挡土墙和岩质边坡为例研究了Copula函数对系统可靠度的影响。结果表明:Copula函数为不完备概率信息条件下抗剪强度参数联合分布模型的构建提供了一种有效的工具。不完备概率信息条件下岩土结构物系统可靠度不唯一,不同Copula函数计算的系统失效概率差别非常大,这种差别在实际工程可靠度设计中应该引起重视。Copula函数对系统可靠度的影响分为两个机制不同的阶段,首先是参数间相关结构对系统中单一失效模式可靠度的影响,其次是每一个失效模式对系统可靠度的影响。
This paper aims to study the impact of the Copulas function for modeling the dependence structure between shear strength parameters on geotechnical system reliability and reveal how the dependence structure of shear strength parameters affects the system reliability. The method for modeling the dependence structure of shear strength parameters with incomplete probability information is first introduced. Then the Monte Carlo-based simulation is performed to analyze the system reliability by taking into account Copula-based bivariate distributions of shear strength parameters. Finally typical geotechnical structures such as a retaining wall and a rock wedge slope are analyzed to demonstrate the impact of Copula selection on geotechnical system reliability. The results indicate that the Copulas function provides an effective way to construct the bivariate distribution of shear strength parameters. The difference of geotechnical system probabilities of failure among various Copulas is significant and should not be ignored. In addition, the impact of Copula-based dependence structure on geotechnical system reliability consists of two processes essentially: one is the impact of dependence structure between shear strength parameters on the probability of each failure mode and the other is the impact of all failure modes on system reliability.