大直径土压平衡盾构施工穿越建筑物沉降预测及控制技术研究

Prediction and Control Techniques for Building Settlement Induced by Large-Diameter EPB Shield Tunnelling

文章以北京地铁十四号线首次采用大直径土压平衡盾构穿越建筑物施工为例．利用数值模拟对建筑物沉降进行了预测，并与工程监测数据进行了对比分析。研究结果表明，建筑物沉降值和倾斜值在控制标准之内．说明设计施工方案可行；盾尾空隙沉降占最大沉降值的30％～50％，应以此为主采取措施来达到预期的沉降控制目标；地面预埋管注浆是控制沉降有效的辅助措施；盾构施工中土体塑流性改善、掘进参数控制、出土量、盾尾同步注浆、二次补注浆是沉降控制的关键环节。

Based on the construction practice of a large-diameter EPB shield first adopted for Beijing Metro Line 14, the building settlement induced by shield tunneling is predictied by numerical simulation and a comparative analysis of predicted and measured data is carried out. The results show that： the settlement and inclination of buildings are within control standards and the design and construction scheme is feasible; the settlement at the shield tail is 30% to 50% of the maximum settlement and it is a critical factor to control; the grouting via the embedded pipes on the ground is an effective auxiliary measure to control settlement; the key points to control settlement during shield construction include improvement of the plastic flow properties of the soil mass, control of driving parameters, extracted muck volume, simultaneous grouting at the shield tail, and secondary grouting.