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针对南水北调中线穿黄连接段大断面饱和黄土隧洞的成洞条件问题 ,应用岩土工程软件FINAL对几种可能的方案进行了施工仿真试验研究。研究结果表明 :①新奥法施工方案在该大断面高水头饱和黄土围岩中能够成洞 ;只需紧跟掌子面喷护 ,挂网 2 5cm加系统锚杆形成柔性支护圈即可维持围岩稳定 ;②双洞中心相距 2 .5倍洞径时应力与变形的相互影响小于 5 % ;③双洞合一的掏槽一次永久衬砌方案也可成洞 ,且施工技术要求最低 ,但洞周变形最大 (约 1 40mm) ;④双洞合一的预制混凝土超前压桩衬砌方案虽施工工艺复杂 ,但却能最大限度的限制围岩变形 (最大沉降小于 1 0mm) ,在重要建筑物底下穿过时 ,可能是首选方案。
Aiming at the hole forming conditions of the large cross-section saturated loess tunnel in the mid-route of South-to-North Water Diversion Project, several construction schemes are simulated by the software FINAL of geotechnical engineering. The results show that: ①New Austrian method construction program in the large section of high head saturated loess wall rock can be a hole; just follow the palm face spray, mesh 25cm plus system anchor to form a flexible support ring The stability of the surrounding rock is maintained; ② the mutual influence between stress and deformation when the double-hole center is 2.5 times of the hole diameter is less than 5%; ③ a permanent lining scheme of the double-hole undercutting hole can also be made into a hole and the construction technology requires minimum, But the deformation of the hole is the largest (about 1 40mm). ④ The prefabricated pre-piling lining with one hole and one hole, although complicated in construction technology, can limit the deformation of surrounding rock to the maximum (the maximum settlement is less than 10mm) Underneath the object may be the preferred solution.