Abstract: Ground settlement caused by shield tunnel construction is always a difficult problem in the engineering practice. Based on the double-line tunnel between Fangzhuang and Shilihe Station on line 14 of Beijing Metro, a three-dimensional numerical calculation model was constructed to simulate the successive excavation and grouting process of the double-line tunnel. The modified Cam-Clay model was used to calculate the soil mass, and the stiffness transfer method was used to simulate the shield tunneling process and synchronous grouting construction process. The influence of grouting pressure, grouting volume behind the wall, consolidation and hardening of slurry changing with time and successively tunneling construction on the surface deformation was analyzed. The results show that reasonable determination of grouting volume and grouting pressure can effectively control surface subsidence. The calculation results of settlement considering the hardening of slurry is larger than that without considering the hardening factors. Under the condition of optimum grouting pressure and grouting volume, the calculated results are in good agreement with the measured values when the volume strain method is used and the slurry hardening is considered. In the later stage, the line construction not only causes the further settlement of the stratum, but also increases the structural deformation of the first constructed tunnel.

Key words: geotechnical engineering, double-line tunnel, stiffness transfer method, grouting pressure, consolidation hardening, convergence displacement

摘要： 盾构隧道施工引发的地层沉降一直是困扰工程界的难题。以北京地铁14号线方庄—十里河站区间双线隧道为背景，构建三维数值计算模型对先后线路隧道开挖和注浆过程进行分析。采用修正的剑桥模型计算地层土体，采用刚度迁移法模拟盾构掘进过程和同步注浆的施工过程。分析了壁后注浆压力、注浆量、浆液随时间固结硬化及先后掘进施工对地表变形的影响。结果表明：合理确定注浆量和注浆压力能够有效控制地表沉降，考虑浆液硬化的沉降计算结果要大于不考虑硬化因素的结果；在最优注浆压力和注浆量的条件下，用体积应变法模拟注浆并考虑浆液硬化的计算结果更与现场监测值非常吻合；后期线路施工不仅引起地层进一步沉降，还增大了先施工隧道的结构变形。

关键词: 岩土工程, 双线隧道, 刚度迁移法, 注浆压力, 固结硬化, 收敛位移