盾构隧道下穿邻近污水管施工方案研究

以成都地铁18号线一期工程ZDK15+242.34施工断面为研究对象，采用外加厚度为0.02 m的钢套筒加固超近距离（与盾构隧道净距0.324 m） DN800污水管，运用MIDAS/GTS软件对盾构掘进过程进行数值模拟，分析了钢套筒对DN800污水管的加固效果。结果表明:钢套筒可以保证该污水管的安全。在施工过程中，盾构机与钢套筒的距离小于5 m时，钢套筒应力变化最为明显，且在左隧道施工完成时，钢套筒的应力值最大。盾构机在污水管前12 m到后8 m范围内施工时，距离隧道越近，污水管的沉降变化越大。污水管横穿废弃污水管及其内部填充的混凝土，会使污水管的沉降增大，与不穿越废弃污水管相比，污水管最大沉降差值增大1.5倍。

Study on Construction Scheme of Shield Tunneling under Adjacent Sewage Pipe

Herein the construction section ZDK15+242.34 in the phase I of Chengdu Metro Line 18 was taken as the research object. A steel sleeve 0.02 m thick was added externally to reinforce the adjacent DN800 sewage pipe (0.324 m away from the shield tunnel), and then the shield tunneling process was simulated numerically with MIDAS/GTS software so as to analyze the reinforcement effect of the sleeve on this pipe. The result shows that steel sleeve may secure the sewage pipe; during the construction, the stress of steel sleeve varies most obviously when the distance between the shield tunneling machine and the steel sleeve is less than 5 m, and the stress is maximum when the construction of left tunnel is finished; when the shield tunneling machine works within the range from 12 m in the front to 8 m in the rear of the sewage pipe, the closer distance to the tunnel, the larger settlement difference of the sewage pipe. When the sewage pipe traverses waste sewer with concrete filled in, the settlement of sewage pipe increases and, compared with the sewage pipe not traversing waste sewer, the maximum settlement difference increases by 1.5 times.