盾构隧道施工对富水软弱地层的扰动分析

为研究盾构隧道施工对富水软弱底层的扰动影响,以大连地铁某标段盾构隧道施工为例,首先基于修正剑桥模型建立土体本构关系,利用Shell结构单元模拟盾构初衬;然后采用流固耦合方法研究土体固结过程对盾构开挖引起软弱地层扰动问题;最后根据仿真结果与现场实测数据,绘制地表沉降对比分析曲线,给出盾构施工引起地表沉降的动态变化趋势.结果表明：孔隙水在盾构开挖完成后仍持续向隧道方向渗透,并引起距隧道较近区域的扰动趋势大于周围较远区域.本研究对提高富水软弱地层条件下盾构施工过程建模的准确性和实效性、指导盾构施工具有指导作用.

Analysis of Disturbance to Weak Watery Strata from Shield Tunneling

In order to study the disturbance to weak watery strata from shield tunneling,taking the section shield tunneling of Dalian subway construction as example,the constitutive relations of the rock-soil mass were established on the basis of the modified Cambridge model,and the shield primary liners were simulated with the shell structure units.Based on the fluid-solid coupling method,the disturbance influence to the weak watery strata from shield tunneling were discussed during soil-rock consolidation.According to the simulation resuits and the measured data,the contrastive analysis curve about surface subsidence between the simulation and the measured data were plotted,and the dynamic change trends of the surface subsidence caused by the shield tunneling were analyzed.Results show that,the pore water still permeates to the direction of the tunnel continually after the shield excavation completes,resulted in larger disturbance of close distance tunnel than the farther area.The study will enhance the accuracy and the effectiveness of shield tunneling process modeling in weak watery and strata conditions and provide the guidance for shield tunneling.