基于粘弹性边界的时域波动理论,建立了二维平面SV波斜入射的输入方法.以成兰铁路某山岭隧道浅埋偏压段为研究对象,采用ANSYS研究了地震波入射角度对浅埋偏压隧道地震反应的影响.结果表明:地震波斜入射时,隧道结构的地震响应与垂直入射有明显差异,结构反应随着入射角度的增加而增大,斜入射对隧道竖向地震响应影响更为显著.入射角度对衬砌弯矩峰值包络图影响较大,对轴力峰值包络图影响很小.斜入射时,拱顶、仰拱和拱腰的弯矩增加较多,是隧道衬砌抗震的薄弱部位.
Based on the time-domain wave theory of viscous-spring artificial boundary,a 2D input method for an oblique incidence of plane SV wave was proposed.Taking a shallow-buried unsymmetrical-loading mountain tunnel in Cheng-Lan Railway as the research object,the proposed method was used through ANSYS to study the influence of the incident angle on the seismic response of shallow-buried unsymmetrical-loading tunnels.The results showed that the dynamic responses of the tunnel subjected to an oblique incidence of seismic wave were clearly different from those due to the vertically incident seismic wave.Structural responses increased with the increase of the incident angle.Oblique incidence had more significant influence on the vertical seismic responses of a tunnel.The incident angle had a greater influence on the envelope diagram of the maximum bending moment,but little influence on the maximum axial force.On the condition of oblique incidence,the bending moment of the arch crown,the inverted arch and the hance would increase considerably,thus representing the weak positions of tunnel linings during earthquake.