地下结构纵向抗震动力可靠度分析

将沉埋隧道地震反应分析的数学模型应用于地下结构随机地震响应分析,阐述了采用动力分析方法求结构体系的脉冲响应函数的原理和方法,采用傅立叶变换原理和随机振动理论,建立了地下结构纵向随机地震响应统计特征的数学表达式。将结构随机地震响应看成是1个泊松过程,建立了采用首次超越破坏理论计算地下结构抗震可靠度的数学公式。以南京长江越江隧道初步设计方案(沉管段)为例,计算了其在高斯平稳随机过程地震动作用下的动力反应均方根值和纵向抗震动力可靠度。为地下结构整体随机地震反应分析及动力可靠度的研究提供了一种分析途径,为以可靠性理论为基础的地下结构抗震概率设计规范的制订奠定了理论基础。

DYNAMIC ANALYSIS OF LONGITUDINAL ASEISMIC RELIABILITY OF UNDERGROUND STRUCTURES

The mathematic models of seismic responses used for analyzing submerged tunnels are utilized to study the stochastic seismic responses of underground structures. The principles and methods of computing the impulse-response function for the underground structures with dynamic analysis method are elaborated,and the formulas for evaluating the statistical characteristics of the longitudinal stochastic seismic responses for underground structures are achieved by using principles of Fourier transform and theories of random vibration. With stochastic seismic responses considered as a Poisson process,the formulas for calculating the longitudinal aseismic reliabilities on the basis of the first passage mechanism are established. The Nanjing Changjiang Tunnel is used as an example to compute the square-mean-root responses and the longitudinal aseismic reliabilities under stationary random earthquake loads. A new analysis method proposed in this paper can serve as the theoretical basis for the speculation standards of the stochastic aseismic design for underground structures based on reliability theories.