黄土区基坑施工诱发地铁隧道位移及加固措施分析

Analysis on Reinforcement Measures and Subway Tunnel’s Deformation Caused by Foundation Excavation Construction in Loess Area

依托黄土区某深大基坑工程,采用数值分析法综合考虑基坑降水及开挖卸荷的耦合作用,研究了二维基坑“先深后浅”特定卸荷路径下诱发近接运营地铁隧道位移的发展规律,并进一步分析了针对本工程提出的“隔离桩+止水+土体加固”措施的控制效果。结果表明,隧道竖向位移发展表现为先沉降后隆起,水平位移发展表现为先增大后趋于稳定;加固措施有效地减弱了基坑施工诱发的隧道竖向位移,隔离桩制约了左线隧道水平位移的扩大,该措施可用于本工程三维基坑大降水、大开挖施工诱发的隧道位移控制。

Considering the coupling effect of the foundation excavation dewatering and excavation unloading by the numerical analysis method based on a foundation excavation project in loess area in this paper, the subway tunnel’s displacement development law caused by the two-dimensional foundation excavation under the “first deep then shallow” specific unloading path is studied. The control effect of the “isolation pile + water stop + soil reinforcement” measures proposed for this project is further analyzed. The results show that the tunnel’s vertical displacement development law shows settlement first and then uplift, and the tunnel’s horizontal displacement development law shows increase first and then tend to be stable. The reinforcement measures effectively weaken the tunnel’s vertical displacement caused by the foundation excavation construction, and the isolation piles restrict the expansion of the left line tunnel’s horizontal displacement. The reinforcement measures can be used to control the displacement of the tunnel caused by the three-dimensional foundation excavation dewatering and large excavation construction.