越江隧道深切槽段上浮机理分析及控制研究

Mechanism Analysis and Control Study on Upward Movement in Deep Groove of Cross-River Tunnel

结合南京越江隧道深切槽段盾构隧道上浮问题,对盾构隧道上浮机理和上浮影响因素进行分析,然后通过数值模拟建立盾构隧道梁弹簧模型对施工期隧道上浮进行模拟,最后针对影响因素提出隧道上浮控制措施。研究结果表明:同步注浆初凝时间越短,掘进速度越快,隧道纵向抗剪刚度越大,后配套自重越大,同步注浆压力差越大,隧道施工期上浮会越小。此外,提前压低盾构姿态、使用摩擦系数更大的橡胶衬垫以及预应力螺栓等也可用来控制隧道上浮。

Combined with the study on upward movement of shield tunnel in deep groove of Nanjing Cross-river Tunnel, this paper analyzes the upward movement mechanism and influencing factors of shield tunnel, then cre- ates a shield tunnel beam-spring model by numerical simulation to simulate the upward movement of tunnel un- der construction and finally puts forward control measures against influencing factors. Research results show that the shorter the initial setting time of synchronous grouting is, the faster the driving speed is, and the greater the vertical shear stiffness, the self-weight of rear supporting system and pressure difference between synchronous grouting, which could make the upward movement period shield posture ahead of time, utilizing rubber gaskets with smaller in the tunnel construction. Besides, lowering larger friction coefficient and pre-stressed bolts can also control tunnel upward movement.