类矩形土压平衡盾构施工引起的地表变形

针对类矩形盾构施工的扰动控制问题，基于弹性力学Mindlin解，考虑刀盘正面附加推力、壳体与土体之间摩阻力、同步注浆压力以及土体损失4种因素的共同作用，采用数值积分法和叠加原理对地表变形进行计算分析.结果表明：4种因素共同作用下类矩形盾构掘进地表相当范围内表现为沉降，最大收敛沉降约为33 mm，开挖面前方的沉降影响主要集中在前方10 m范围；同步注浆压力产生的地表隆起可以部分抵消土体损失引发的沉降，因而合理的同步注浆有利于沉降控制；4类因素中，正面附加推力和盾壳摩阻力产生的地表变形很小.理论结果与实测数据基本吻合，可为后期类矩形盾构隧道施工的扰动控制提供理论参考.
Abstract: The disturbance control of quasi-rectangle shield tunneling was analyzed. The coupling effects of the following four factors-the horizontal excess pressure at the excavation face, the friction between the shield skin and soil, the grouting force outside the tailskin and ground loss were analyzed based on the Mindlin solution. The ground surface deformation was calculated with numerical integration method and superposition. (1) Superposition of these four factors causes large ground surface settlement near the tunneling area, with a convergence settlement about 33 mm, and significant settlement occurs within 10 m ahead of the face; (2) Grouting force causes significant heave and can partially offset the settlement induced by ground loss, thus appropriate grouting can assist settlement control;(3) Of all the four factors, the ground deformation induced by horizontal excess pressure and skin friction is quite small, if compared with the other two factors. The theoretic results accorded with on-site monitoring data, which assists disturbance control of future quasi-rectangle shield tunneling.