摘要
汶川大地震造成都江堰至汶川公路距震中较近的区域多座隧道严重受损,其中隧道洞口段的震害尤为严重。与隧道其他部位不同,洞口段在地震过程中具有与地面结构类似的动力放大效应。通过采用三维离散单元计算程序,研究了含节理隧道洞口段仰坡和衬砌结构的动力放大效应,并与汶川地震隧道实际震害做比较。结果表明:较低刚度的结构面对地震波造成较大的衰减。结构面刚度小于1.5GPa/m时,其对地震波的衰减作用大于仰坡动力放大效应。仰坡坡面与结构面交汇处动力放大效应明显。当结构面刚度等于或大于岩体刚度时,其对地震波的衰减作用不明显。仰坡高度和倾角增大,动力放大效应越明显,且仰坡高度较倾角的动力放大效应明显。所得结论对隧道工程抗减震的研究具有参考意义。
The great Wenchuan Earthquake took place in western Sichuan Province on May 12th,2008. Many tunnels on the highway from Dujiangyan to Wenchuan were damaged severely due to the site located near the epicenter. The seismic damage of tunnel portal was more obvious and grievous than other parts of the tunnel. The tunnel portal demonstrates similar dynamic amplification effect to normal ground structures. Based on the on-site investigation and research,data collection and analysis,the three dimension distinct element numerical analyses were conducted to investigate the dynamic amplification effect of front slope and lining of jointed tunnel portal. The results show that the lower stiffness of structural plane causes the more attenuation of seismic wave. The attenuation effect of structural plane will exceed the dynamic amplification effect when the stiffness of structural plane is lower than 1. 5GPa / m. The dynamic amplification effect is quite evident at the junction of front slope plane and structural plane. The attenuation of seismic wave will become obscure when the stiffness of structural plane is equal or greater than the stiffness of rock. As the height and angle of front slope increase gradually,the dynamic amplification effect becomes apparent. Moreover,the effect caused by the height is more obvious than by angle. All these factors have important implications for aseismic and shock-absorbing technologies of tunnel engineering.
出处
《土木工程学报》
EI
CSCD
北大核心
2013年第S1期269-274,共6页
China Civil Engineering Journal
基金
国家自然科学基金(51178398
51078319)
关键词
汶川地震
山岭隧道
动力放大效应
节理
三维离散单元法
Wenchuan earthquake
mountain tunnel
dynamic amplification effect
joints
3 dimension distinct element method
