九寨沟M_s4.5级地震斜坡体及覆盖层的动响应分析

Analysis of slope and overburden seismic response during the Jiuzhaigou M_s4.5 earthquake

斜坡地形及深厚覆盖层对地震波的放大效应是斜坡失稳及建筑物破坏的关键性控制因素。通过九寨沟薛家坝高位深平硐余震监测,对九寨沟M_s4.5级地震斜坡动响应特征及覆盖层放大效应等进行研究。结果表明:山脚覆盖层及山顶平硐洞口段出现了不同程度的放大效应,且平硐由外至内,地震波的放大效应整体上呈非线性递减并最终趋于收敛。

The amplification effect of slope terrain and thick overburden on seismic waves is the key control factor for controlling slope instability and building failure.The monitoring site of tunnel is located on Xuejiaba,Jiuzhaigou County.Tunnels in the alpine slope are used to place aftershock monitoring instruments of the valley.The instruments monitored the Jiuzhaigou Ms4.5 earthquake on November 7,2017 in Sichuan,China.The seismic response characteristics and the magnification effect of the thick overburden are studied.Results show that different degrees of magnification effect can be found in overburden at the foot of the hill and the entrance of the tunnel.From the outside to inside the tunnel,the amplification effect of seismic waves is in nonlinear decreasing trend and eventually converged.