顶管近接穿越既有箱涵的施工扰动与变形影响分析

Analysis of Construction Disturbance and Deformation Influence of Pipe Jacking near Crossing Existing Box Culvert

为更好地控制顶管施工对周围建(构)筑物的影响,以上海某圆形顶管近接下穿既有箱涵施工为工程背景,建立了考虑顶管-土体-既有地下箱涵相互作用的三维有限元模型,计算分析了不同土体损失、开挖面支撑力等对周围地层和既有箱涵沉降的影响。计算结果表明:既有箱涵沉降随周围土体损失的增大而增加,两者基本呈线性正相关关系;当开挖面支撑力为初始地层压力1.5倍时,顶管施工对既有箱涵结构的扰动最小,一定程度上可以减少顶管施工导致的周围地层及既有箱涵沉降。最后,分析了多种既有箱涵MJS加固方案,提出了优化的加固参数,可为实际工程提供参考支持。

In order to better control the impact of pipe jacking construction on the surrounding buildings(structures),a 3D finite element model considering the interaction of pipe jacking,soil and existing underground box culvert is established based on the construction of a circular pipe jacking near undercrossing existing box culvert in Shanghai,and the effects of different soil losses and supporting forces of excavation surface on the settlement of surrounding strata and existing box culvert are calculated and analyzed.The calculation results show that the settlement of the existing box culvert increases with the loss of the surrounding soil,and there is a positive linear correlation between the settlement of the existing box culvert and the loss of the surrounding soil;when the supporting force of the excavation face is 1.5 times of the initial ground pressure,the disturbance of pipe jacking construction to the existing culvert structure is minimal,which can reduce the settlement of surrounding ground and the existing box cuvert caused by pipe jacking construction to a certain extent.Finally,a variety of existing box culvert MJS reinforcement schemes are analyzed,and the optimized reinforcement parameters are proposed,which can provide reference support for practical engineering.