汶川M_(S)8.0地震公路易损性研究

Research of Highway Fragility Based on the Wenchuan M_(S)8.0 Earthquake

基于汶川地震的公路震害资料,选择地震动峰值加速度作为地震动参数,选用双参数对数正态分布作为易损性函数,将线性结构的公路离散为每1 km一处的工点进行回归分析得到公路结构易损性曲线,再结合公路结构发生某一种破坏状态时的损失比,建立了公路的平均损失率模型。结果表明:在轻微破坏状态下,边坡的易损性大于支挡结构与路基;在毁坏情况下,边坡的易损性则略小于支挡结构与路基;公路整体的易损性比边坡、支挡结构、路基都要大,公路平均损失率在PGA<0.1 g时增长较慢当PGA>0.1 g时,随着PGA的增加开始快速增长。

Using the seismic-damage data of the Wenchuan M_(S)8.0 earthquake,we respectively established the seismic-fragility models of the highway,subgrade,slope,and retaining structure based on the earthquake damage.Selecting the peak ground motion acceleration(PGA)as the ground motion parameters and the double-parameter lognormal distribution as the fragility function,we discretized the linear highway structure into worksites(one worksite per kilometer)for regression analysis according to the highway's own features.Then we established the average loss-rate model of highway structure by combining the fragility curve with the loss ratio of highway structure when it was in a particular failure state.We found that in slight damage state,the fragility of the slope is greater than that of the retaining structure and that of subgrade.In collapse state,the fragility of the slope is slightly less than that of the retaining structure and that of subgrade.The fragility of the highway is higher than that of the slope,the retaining structure,and the subgrade.When PGA was lower than 0.1 g,the average loss-rate of highway increased slowly.When PGA was greater than 0.1 g,the average loss-rate of highway began to increase rapidly.