地铁隧道近距离穿越对上部框架结构的影响

利用有限元软件ABAQUS建立三维有限元模型，通过变化上部框架结构的层数，柱距，独立基础的埋深，隧道的位置等因素研究隧道开挖对上部框架结构的影响．当隧道中心线与框架结构的纵向柱列平行时，本文研究的所有工况的纵向柱列的相邻柱沉降差及整体倾斜比较接近，即上述因素对纵向柱列的影响很小，但对横向柱列的影响不能忽略；当上部框架结构为一层时，白重引起的沉降不满足规范要求；纵向柱列各柱底沿坐标轴2方向的最大位移均超过了层问侧移限值；柱底水平位移会改变柱的受力状态，使一层柱底产生向着隧道中心线方向的弯曲变形，角柱呈双向弯曲变形；沿坐标轴1、2方向相邻柱的最大位移差通常使基础梁被拉长或压短，在基础梁内产生轴向拉力或压力，从而改变基础梁的受力状态；隧道开挖使柱底沿坐标轴2方向往复运动，柱底发生剪切破坏；增加结构空间刚度对横向柱列的影响明显，而对纵向柱列的影响很小；隧道开挖使一层柱顶外侧的拉应力进一步增加，角柱拉应力增加量最大．

Influences of Shield Driven Tunneling on Top Frame-Structure

The influences of tunneling on adjacent existing buildings are analyged,and the FEM models are adopted to predict the settlements and deformations of top structures during tunneling.As to the working conditions discussed there are little differences in the settlement difference of adjoining piles and the incline in longitudinal line of columns when the tunnel and the longitudinal line of columns are parallel,which means that the influences of the factors mentioned above on the longitudinal line of columns can be ignored.Lateral displacements at the bottom of columns in the direction of coordinate 2 exceed the limit recommended by the code for all the working conditions discussed.The corner columns bend both in the directions of 1 and 2 at the bottom.The increase in frame structure stiffness will decrease the settlement differences between columns in the lateral lines,while it will have little effect on columns in the longitudinal lines.