近接运营高铁U型槽基坑开挖方法研究

A Study of the Excavation Method for the Foundation Pit of the U-Shaped Groove near an Operating High-Speed Railway

近接运营高铁基坑开挖工程,对高铁路基及桥梁产生的附加位移,易引起路桥差异沉降的变化,进而直接影响到高铁的安全运营。针对如何控制路桥沉降及路桥差异沉降问题,结合天津武清翠亨路近接高铁顶进铁路立交桥工程,提出了深大基坑"分段开挖、上下分层、同层分片、逐片推进"的开挖方法。并通过PLAXIS3D有限元模型及实际开挖试验的方法验证了该方法的安全性及适用性。数值计算及施工实践显示:该方法在近接高铁基坑开挖施工过程中能取得良好效果,为其他类似工程施工可提供参考。

The excavation for a foundation pit near the high-speed railway results in the additional differential settlement between the roadbed and the bridge,directly affecting the safe operation of the high-speed railway. Aiming at solving the technical problems of the jack-in construction of the high-speed railway flyover interconnected with the high-speed railway foundation pit near the Cuiwei Road of Wuqing District of Tianjin city, the excavation methods of the section-by-section excavation, upper-and --lower layer-dividing excavation,section-dividing-in-the-same-layer excavation,and the piece-by-piece progressing are put for- ward in the paper. The safety and application of the methods are proved with both the PLAXIS3D finite element model and the practical excavation tests. Both the numerical calculation and the construction practice show that the above-mentioned methods achieve very satisfactory effects in the excavation project of the foundation pit near the high-speed railway. The success of the project may serve as a useful reference for other projects of similar types.