神座隧道大变形治理措施应用研究

Application of Treatment Measures of Large Deformation in Shenzuo Tunnel

为解决神座隧道初支的大变形问题,根据“以放为主,限量抵抗,抗放结合,多挖少支”的原则,提出了采用限阻耗能支护结构作为大变形治理方案:1)增大预留变形量;2)在钢拱架拱腰处设置限阻器;3)在初支背后预留一定空间填充柔性材料。旨在通过限阻器和柔性材料的压缩变形对支护结构进行让压控制,以释放围岩能量。治理结果表明:1)应用限阻耗能支护实现了结构“支得住”的目标,但由于预留变形量不足及隧道左侧偏压,出现了单侧部分初支侵限的情况;2)在后续施工控制中,需根据隧道不对称变形的特征对预留变形量、柔性材料填充厚度和限阻器的可压缩量、位置等进行针对性调整,保证二衬净空。

In order to solve the large deformation problem of Shenzuo tunnel,according to the principle of"giving priority to drainage with limited resistance,in combination with anti-drainage,more excavation and less support",the support resistant limiting damper(SRLD)was proposed as a large deformation control measure.Firstly,it is to increase the reserved deformation.Secondly,it is to set the SRLD at the waist of steel arch.Thirdly it is to reserve some space behind the initial support to fill flexible materials.Through the compression deformation of the restrictor and flexible materials,the support structure can be controlled to release the energy of surrounding rock.The management results indicate that the application of the SRLD achieves the goal of"able to support the structure",but due to the insufficient reserved deformation and the biased pressure on the left side of the tunnel,the unilateral partial initial support is beyond limit.In the subsequent construction control,it is necessary to adjust the reserved deformation,the filling thickness of the flexible material,the compressibility and the position of the SRLD to ensure the clearance of the secondary lining according to the characteristics of the tunnel asymmetric deformation.