盾构掘进施工对周边单桩变形影响研究

Research on the Deformation of Single Pile Induced by Adjacent Shield Driving

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模型,研究了盾构隧道施工对周边单桩变形的影响,结果表明:盾构隧道施工过程中,桩身横向位移在隧道中心位置处最大;盾构切削面距离桩体9 m、6 m时,桩身的横向位移较小;随着盾构机进一步掘进,桩身横向位移全部偏向隧道,桩身位移曲线严重弯曲;当盾构切削面越过桩基3 m后,桩身横向位移变化较小,竖向变形沿桩身变化较小;随着盾构机掘进,其值逐渐增大。当桩长增加时,桩底的横向位移、竖向位移均随之减小,桩长对桩身沉降的影响比较明显。盾构正下方穿越单桩时,桩身竖向位移大于沿隧道轴向位移,桩底与盾构顶部的施工安全距离约为3 m。

The numerical analysis is used to study the deformation of single pile induced by adjacent tunnel construction of light-railway line 1 of Suzhou City.The result of numerical simulating shows that the lateral deformation is greatest in the tunnel center of the pile.The whole pile lateral deformation is smaller,when space between shield excavation face and single pile is 9m and 6m,respectively.With the further shield driving,the whole pile lateral displacement deviates to tunnel,and the displacement curves bend seriously;When spacing of shield beyond the pile is greater than 3 m,the whole pile lateral deformation changing is smaller.The pile vertical deformation becomes little along the pile and changing greater and greater with the shield driving.When the pile length becomes longer,the pile lateral and vertical deformation become smaller,The vertical deformation is influenced by pile length significantly.When shield drives below single pile,pile vertical settlement is greater than tunnel axis displacement.The safe construction distance is 3 m between pile end and sheild top.