盾构掘进施工对群桩基础变形的动态影响研究

针对苏州轻轨1号线盾构隧道区间施工情况,采用三维有限元数值计算模型,研究了盾构施工对侧边群桩变形的动态影响,结果表明:当盾构机切削面逐渐逼近群桩时,各单桩的隧道轴线处横向位移背离隧道,承台背离隧道发生倾斜;当盾构到达各单桩时,横向位移在隧道轴线处偏向隧道且为最大,承台发生了双向倾斜;当盾构逐渐远离群桩时,各单桩横向位移变化较小,承台的双向不均匀沉降减小。随着盾构的掘进,群桩整体沿着掘进方向移动,桩身沿隧道轴向位移在隧道轴线处达到最大。当群桩基础的桩底位于隧道轴线处和隧道轴线以上时,群桩承台仅仅发生偏向隧道的单向倾斜;当群桩基础的桩底位于隧道轴线以下时,群桩承台则产生了双向倾斜。

Research of the Dynamic Deformation Influence of Pile Group Induced by Adjacent Shield Driving

The numerical analysis is used to study the dynamic deformation influence of pile group by adjacent shield construction of tunnel on light-railway line 1 in Suzhou city.The result of numerical simulation shows that the lateral deformation of single pile in the group pile deviates from that of the tunnel,and the pile group cap deviating from tunnel leans,when the shield excavation face approachs to pile group.When the face arrives at the single pile in the pile group,the lateral deformation of single pile is the greatest at the tunnel axis,and the cap bidirectionally leans.When the face is far from the pile group,the lateral deformation of single pile changes a little,and the uneven settlement of cap decreases.With the shield driving pile goup moves along the driving direction,the single pile deformation along axial direction of tunnel is the greatest at the tunnel axis.When the pile end of pile group is at and above the tunnel axis,the cap unilaterally leans to ward the tunnel.When the pile end is below the tunnel axis,the cap bidirectionally leans.