列车振动荷载作用下某岩质边坡应力应变动力响应分析

Dynamic response analysis of a rock slope under train vibration load

以某高速铁路隧道进口边坡为研究对象,采用FLAC3D软件分析了列车振动荷载对该边坡岩体的应力、变形及稳定性的影响。数值模拟结果显示,在列车振动荷载作用下,隧道两侧及底部最大、最小主应力均产生集中现象,最大主应力较自重应力场下增加1～2MPa,最小主应力较自重应力场下增加0.5～1MPa;隧道顶部最大、最小主应力均与自重应力场下基本一致;隧道进口边坡总位移增量最大值区域主要分布在边坡顶部及隧道正上方坡顶区域,自坡顶往坡底总位移增量逐渐减小,最大总位移增量约为2.15cm;列车振动荷载将在边坡内地层分界面附近、软弱夹层内、构造结构面附近、开挖面附近形成剪应变增量带,对边坡的稳定性极为不利。

This article analyzed the stress, deformation and stability of a tunnel entrance slope under train vibration load by FLAC3D. Numerical simulation results show that the maximum and minimum principal stress will concentrate at both the tunnel sides and the bottom of the tunnel, and the increscent of maximum principal stress caused by train vibration load is 1 - 2MPa, and the inerescent of minimum principal stress is 0.5 1 MPa. The maximum and minimum principal stresses are almost the same as they were located in self - weight stress field. The maximum total displacement increment region mainly distributes in the top of the slope and the top just above the tunnel, the total displacement increment decreases from the top to the foot of the hill, and the maximum total displacement increment is about 2.15cm. Shear strain increment zone may appear near the interface of layers, in soft layers, and near the structure planes and excavation surface, which is an extremely unfavorable thing to the stability of the slope.