高地应力软岩隧道预留空间法试验研究

Experimental Study on the Reserved Space Method for Tunnels in Soft Rock with High Ground Stress

兰渝铁路多座隧道通过高地应力软岩地层，施工中大变形问题极其突出。文章依托毛羽山隧道工程。通过对预留空间法应力释放进行了构思与试验分析，揭示了高地应力软岩隧道采取预留空间法的变形规律和应力释放能力。试验结果表明，通过采取预留空间法，可以解决高地应力软岩条件下施工的应力释放问题，使初期支护处于安全状态；对预留空间法进行设计时，柔性防护罩可采用4×Ф22mm格栅钢架及25cm网喷混凝土，钢架纵向间距为1榀／0．75m，预留空间量可取30—50cm。

Many tunnels on the Lanzhou-Chongqing railway pass through soft rock with high ground stress, where large deformation problems are extremely prominent during tunnel construction. Using the construction of the Maoyushan tunnel as an example, this paper, based on the stress release concept and the reserved space method, reveals the deformation law and stress releasing ability of tunnels in soft rock with high ground stress. The results show that stress release is obtainable by the reserved space method during construction in soft rock with high ground stress, ensuring the safety of the primary lining. As for the flexible protective cover, it may be formed by 4φ22 mm lattice girder and 25 cm shotcrete with wire mesh, with the longitudinal distance between two steel frames being 0.75 m and the reserved space being 30~50 cm.