超大矩形顶管施工诱发邻近既有桩基响应数值分析

Numerical Analysis of Response of Adjacent Existing Pile Foundation Induced by Super Large Rectangular Pipe Jacking

超大矩形顶管的施工往往会对周边既有建(构)筑物桩基的力学性能产生影响,顶管施工造成的土体损失、摩擦力等会使邻近桩基产生变形。本文围绕某超大矩形顶管工程开展研究,利用PLAXIS 3D建立超大矩形顶管近距既有桩基施工三维数值模型,分析超大顶管施工对邻近既有桩基的力学性能影响,并探讨埋深、推进距离以及桩-顶管间距等不同因素下顶管施工对邻近既有桩基的影响规律。结果表明:超大矩形顶管施工对邻近既有桩基力学性能影响较大;近端桩和远端桩的最大弯矩随着桩-顶管间距增大而减小;上部桩及下部远近端桩最大弯矩均随着盾构推进而呈非线性增加;下部桩远端最大弯矩大于下部桩近端及上部桩弯矩。

The construction of super large rectangular pipe jacking often affects the mechanical properties of the pile foundations of the surrounding existing buildings(structures) because of the deformation of adjacent pile foundation induced by the soil loss and the friction between soil and pipe.The present research mainly focused on the research of a super large rectangular pipe jacking project in Jiaxing,simulated a three-dimensional numerical analysis to investigate the effect of super large rectangular pipe jacking construction on the mechanical properties of adjacent existing pile foundation using PLAXIS 3 D.Furthermore,the influence of pipe jacking construction on adjacent existing pile foundation under different factors such as buried depth,advancing distance and pile pipe jacking distance were addressed.The results showed that the pipe jacking construction had a significant effect on the mechanical properties of adjacent existing pile foundation,the maximum bending moment of the adjacent end pile and the far end pile decreased with the increase of the pile pipe jacking distance,the maximum bending moment of the upper pile and the far and near end pile increased nonlinearly with the advance of the shield.It was also found that the maximum bending moment of the far end of the lower pile was greater than that of the near end pile and the upper pile.