汶川M_(s)8.0地震隧道易损性及平均损失率分析

Seismic vulnerability and average loss ratio analysis of mountainous tunnels based on M_(s)8.0 Wenchuan earthquake

基于汶川地震震害资料,通过回归分析得到了山区隧道结构整体与各部分的地震易损性模型。选择峰值地面加速度(peak ground acceleration,PGA)作为地震动参数,以对数正态分布函数作为易损性模型,利用极大似然估计得到隧道结构整体及各部分(洞口浅埋段、洞口过渡段、普通段、断层破碎段)的地震易损性曲线,对比分析了隧道整体及各部分的地震易损性特点并进行了探讨。结果表明:轻微破坏条件下,洞口浅埋段的地震易损性要高于其他部分。随着破坏程度的增加,断层破碎带段的地震易损性逐渐高于隧道其他部分。根据隧道结构特定破坏等级的损失比,建立了隧道的平均损失率模型。依据文中建立的隧道易损性模型及平均损失率模型可以在将来发生类似地震时快速地进行地震损失评估。

Based on the seismic damage data of Wenchuan earthquake,the seismic vulnerability model of entirety and different sections of mountainous tunnel is obtained by regression analysis.The peak ground acceleration(PGA)was selected as the ground motion parameter and the lognormal distribution was selected as the vulnerability model,and the seismic vulnerability curves of the tunnel structure of entirety and different sections(entrance shallow burial section,entrance transition section,ordinary section,fractured section)were obtained by the maximum likelihood estimation,and the vulnerability characteristics of different section and the whole tunnel were compared and analyzed.Under the condition of slight damage,the seismic vulnerability of the entrance shallow burial section is higher than that of other section.With the increase of the degree of damage,the seismic vulnerability of the fractured section is gradually higher than that of other sections of the tunnel.The average loss rate model of the tunnel was established by combining the loss ratio of tunnel structure in a specific failure state.The tunnel vulnerability models and average loss ratio model established in this paper can be used to evaluate the seismic loss rapidly in the event of similar earthquakes in the future.