盾构下穿城市房屋施工风险与对策研究

A Study of Construction Risk and Countermeasures for Shield Tunnelling Under Urban Buildings

文章针对无锡地铁1号线(大学城站—雪浪站)区间盾构下穿房屋特殊工况,进行了风险评估及处理。一是针对下穿房屋深水井,计算了屋内水井位置的土压力强度,并对在注浆压力作用下可能被击穿的水井进行了回填处理;二是针对下穿老旧房屋施工的安全,开展了房屋基础结构形式、使用情况及房屋安全性能、可控沉降量的调查评估,提出了盾构机均匀连续掘进、少纠偏、勤监测等施工对策。结果表明:土压力强度计算方法、盾构掘进参数控制、盾构姿态调整及监控量测手段是可行且正确的,达到了施工安全性的要求;盾构下穿房屋沉降量最大值为8.2mm,无任何险情出现。

A risk assessment and corresponding treatment are carried out for the special working conditions regarding shield tunnelling under houses for the Wuxi Metro Line 1（from the College town station to the Xuelang station）. There are two problems that need to be solved： 1） the passage under the houses, for which the earth pressure intensity shall be calculated and backfilling shall be adopted for the deep well, which may breakdown under the grouting pressure; and 2） maintaining construction safety during tunnelling under the old houses, whose foundational structures, service conditions, safety performance and controllable settlement shall be investigated and evaluated. For these problems, such construction countermeasures as uniform and continual shield driving,less correction of alignment deviation and regular monitoring are presented. The results show that these countermeasures are feasible and appropriate for the requirements of construction safety, including calculation of earth pressure intensity, control of shield tunnelling parameters, shield attitude adjustment and monitoring and measurement; when the shield passed beneath the houses, no danger occurred and the maximum settlement was8.2 mm.