上部建筑物对隧道结构地震响应的影响研究

采用有限元软件ABAQUS，基于一致黏弹性人工边界和波动输入，建立上部建筑物-土-隧道相互作用二维平面应变模型，利用等效线性化模拟土体非线性,输入不同频谱特性的三条地震动，研究了上部建筑物的刚度、层数(高度)、与隧道间距和隧道埋深等因素对隧道地震响应的影响。分析结果表明，上部建筑物的存在对隧道地震响应的影响不可忽视，影响程度可达到30%左右。上部建筑物与隧道的间距、层数(高度)、刚度不同，对隧道地震响应的影响程度也会发生变化。其中间距和层数(高度)影响较大，间距越大，影响越小，当间距与建筑物宽度的比值超过2之后，建筑物的存在对隧道的影响可忽略；建筑物的层数越多、高度越高，对隧道的影响越大，18层时使隧道最大主应力峰值和相对变形的增加较6层时增大了20%~30%。建筑物的刚度对隧道响应的影响较小。在对隧道进行抗震设计时，应考虑上部建筑物可能对其造成的不利影响。

Influence of building on dynamic response of underneath tunnel

Based on the equivalent viscoelastic artificial boundary element and wave motion input, a series of two-dimensional plane strain models of above building-soil-tunnel were built to study the influence of above building on the dynamic response of the underneath tunnel using the finite element software ABAQUS. The dynamic nonlinear effects of the soil are considered by using the equivalent linear method. Three seismic input earthquake waves with different spectrum characteristics were used here as input motion. The influences of the stiffness, layer number (height) and spacing of the above building and the depth of the underneath tunnel on the seismic response of the tunnel were studied. Results show that the influence of above building cannot be ignored. The influence degree can reach about 30%. The spacing and layer number (height)have a great impact on the dynamic response of underneath tunnel. The larger the spacing, the smaller the influence on the tunnel. The influence of the above building on the tunnel can be ignored when the ratio of the distance to the width of the building is more than 2. The larger of the layer number, the greater influence on the tunnel. The increase of the maximum principal stress and relative deformation of the tunnel at the 18-story building increases by 20%-30% compared with the 6-story building. The stiffness of buildings has little effect on tunnel response. In the seismic design of the tunnel, the adverse effects of the above building structure may be considered.