拱北隧道明挖基坑 富水软弱基底加固方案研究

拱北隧道是建设在建筑物密集区的软土地层中的宽体隧道。以该隧道海域明挖段超大基坑的基底加固方 式为研究内容，采用数值分析方法，对比分析满堂、裙边及抽条 3 种不同加固方式对基底沉降变形及围护结构受 力变形的影响，为隧道的基底加固方式比选提供参考。计算表明，所选节段满堂加固对基底的沉降及隧道结构的 变形控制效果更佳，对围护结构的受力影响不大；裙边和抽条的加固效果相近。因此，在不同地质条件下不同节 段可以通过数值计算较好地模拟比较不同的隧道基底加固方案对隧道结构稳定性的影响规律，并结合经济性指 标，选择最合理的加固方案。

Study on the Reinforcement Scheme of the Soft Basement of the Foundation Pit of Gongbei Tunnel

Gongbei Tunnel is a wide-body tunnel built in the soft soil layer of a dense built-up area. A numerical analysis method is used to study the foundation reinforcement method of the large excavation section of the tunnel. The effects of three different reinforcement methods, namely full body, skirt, and strip reinforcement, on the deformation of the foundation settlement and the stress deformation of the surrounding structure are analyzed for comparison; this provides a reference for the foundation reinforcement of the tunnel. The calculation shows that the foundation stabilization method of the selected segment, which is consolidated by the entire foundation pit, has a better effect on the basement subsidence and the deformation control of the tunnel, but has little influence on the stress of the retaining structure. Therefore, the most reasonable reinforcement scheme can be selected based on the comparison of the influence of different tunnel base reinforcement schemes on the stability of different tunnel structure sections under different geological conditions, determined by numerical simulation and combined with economic indicators.