联合超前支护技术在水下浅埋软岩公路隧道中的应用

Application of combined advanced support technology in the shallow,soft rock and underwater highway tunnel

摘要: 湘江大道浏阳河隧道是一座用矿山法施工的水下浅埋软岩公路隧道,应用"全断面注浆+管棚+小导管"的联合超前支护技术。首先通过数值模拟,对比分析不采取任何超前支护措施、仅采取全断面超前预注浆、采取联合超前支护措施三种情况下的初衬拱顶沉降和最大轴力;然后根据应用实践,总结联合超前支护的主要技术参数;最后通过现场观察和现场测试浏阳河水位、初衬背后的水压力、初衬的拱顶沉降和水平收敛、连接小导管的型钢拱架的应力、二衬砼的应力等,分析联合超前支护的作用机理及效果。结果表明:三种超前支护措施通过互相补充加强,可为水下爆破开挖创造良好的条件、可与围岩共同作用形成承载拱、可改善初衬的受力变形状况、可避免过早施作二衬。

Abstract: Liuyanghe tunnel is the shallow,soft rock and underwater road tunnel by the mining method,and the combined advanced support technology was applied,including full-sectional grouting,pipe roof,and small duct.Firstly,a finite element model was established to analyze crown settlement and maximum axial force of the initial lining without the advanced support,with the full-sectional grouting support or the combined advanced support;then,the practical technical parameters of the combined advanced suppo...