盾构隧道近距离侧穿高层建筑的影响探析

摘要

this article through the establishment of three-dimensional finite element model based on single pile cofferdam,shield tunnel is studied through the deformation and internal stress situation of high-rise building pile foundation platform,and based on the analysis of the different soil bin under pressure,grouting pressure and the stiffness reduction factor of shield tunneling on the properties of pile foundation are studied.The results show that the pile body and the direction of the vertical displacement of the basic can be neglected;The pile along the tunneling direction,pile body around the pile caps is happen flexure deformation along the direction of shield tunneling;When the pile body along the vertical direction,the settlement of the tunnel center maximum;As a result of the existence of pile caps is made negative friction resistance of pile top is small,slowly become positive friction area;The increase of soil bin pressure can GaoBian pile body displacement direction,the grouting pressure,the greater the the settlement of pile top steady-state value is smaller,more caps on pile head load;Unloading of soil disturbance,pile deflection decreases,and reaches a steady state with the corresponding settlement of pile top is smaller.%通过建立基于承台单桩的三维有限元模型,研究了盾构隧道穿越高层建筑桩基台的变形和内应力情况,并以此为基础分析了不同土仓压力、注浆压力和刚度折减系数下盾构隧道掘进对桩基性能的影响规律.研究结果表明:桩身与掘进方向垂直方向位移基本可以忽略不计;桩身沿掘进方向时,桩身绕承台沿盾构掘进方向发生挠曲变形;当桩身沿掘进竖直方向时,隧道中心沉降达到最大;由于承台的存在使得桩顶层负摩阻力区慢慢较小,最终成为正摩阻区;土仓压力的增大能告便桩身的位移方向,注浆压力越大,桩顶稳定态的沉降值越小,桩顶承载更多承台荷载;土体卸荷扰动减小,桩身挠曲变形减小,达到稳定状态时随对应的桩顶沉降也就越小.