三管盾构隧道下穿铁路引起的地表位移及其控制技术

采用三维数值模拟方法,结合上海轨道交通9号线R413标段,进行三管并行盾构隧道近接下穿南新环铁路引起的地表位移及其控制技术研究。数值分析中,利用温度升降产生的膨胀和收缩效应模拟注浆压力和压力的消散,使得分析过程在力学效应上更接近盾构施工的工作状态。引入轨道高低偏差值来控制地表位移。研究结果表明:地层加固前,各隧道施工时地表的横向位移有明显的叠加效应,距离越近,效应越明显,且最大位移值已超过限值;当采用分块注浆加固地基并配合旋喷桩施工的地层位移控制技术后,地表位移得到有效的控制,现场沉降实测结果验证了控制技术的有效性,确保盾构隧道安全下穿铁路和列车的安全运营。

Ground Displacement Caused by Three Pipes Shield-Driven Tunnels Through below Railway on the Ground and Control Technology

Research on the ground displacement caused by three pipes shield-driven tunnels through below Nanxinhuan railway on the ground and the corresponding control technology has been studied.The main method is to adopt three-dimensional numerical simulation based on R413 project of Shanghai Metro the ninth line,then compare with the in-site data to draw the conclusion.In the numerical analysis,the expansion and contraction caused by temperature increasing and decreasing is taken to simulate the scatter and disappearance of grouting pressure,which makes the analysis process closer to the working condition of shield construction in terms of mechanical effect.At the same time,two rails heights deviation is introduced to control ground displacement.Research results indicate that ground displacement caused by each pipe tunnel is added to another caused in the cross-section direction before strata being reinforced.This action is more distinct with shorter distance between two pipes tunnels,and the maximal displacement exceeds the limit.However,ground displacement is effectively controlled by using block grouting and rotary jet grouting piles.Field test results of in-situ displacement have proved the validity of the control technology,which can ensure the shield-driven tunnel safely under-cross the railway and guarantee the safe operation of trains.