高烈度区双洞隧道洞口段地震响应分析与振动台模型试验

Seismic response analysis and shaking table test realization of double tunnel entrance in high intensity zone

强震作用下,隧道地下结构损伤严重,其中洞口段更是抗震的薄弱环节,但其影响规律和特点目前尚缺乏系统的计算分析和研究。以强震区扯羊隧道为例,首先采用FLAC3D对双洞隧道洞口段地震响应进行分析,再用模型试验的方法进行洞口段模型试验,测量其地震响应应变规律,观测其震害发展情况,并与数值分析结果相互验证。结果表明:地震作用下,隧道仰拱横向位移较大;随着隧道埋深增加,内力逐步增加,其中墙角部位内力较大;洞口处隧道围岩在强震作用下会产生贯通性裂缝,影响隧道洞口稳定;地震作用下的明洞与暗洞交接处内力较大;地震作用下的双洞隧道之间存在较强的动力相互作用。

Under the action of strong earthquake,the underground structure of the tunnel is seriously damaged,and the tunnel entrance is the weak link of the tunnel.Now we are still lack of systematic analysis and research about tunnel earthquake.The FLAC3D software is used to calculate the seismic response of the tunnel entrance section with the numerical analysis method.The seismic response of the tunnel entrance is tested by the model test,and the seismic response strain law is measured and the development of earthquake damage is observed.The numerical analysis and experimental results show that the lateral displacement of the inverted arch of the tunnel is larger than the other monitoring point under the action of earthquake;with the increase of the depth of the tunnel,the internal force gradually increases,and the internal force at the corner of the tunnel is larger than the other monitoring point;the surrounding rock of the tunnel at the entrance will produce penetrating cracks under the action of strong earthquake,which will affect the stability of the tunnel entrance;the internal force of intersection of the open tunnel and hidden tunnel under the action of earthquake is larger than the other monitoring point.Strong dynamic interaction exists between two tunnels under earthquake action.