高地应力软岩隧道释放-约束平衡法控制变形技术

Technology for Control of Deformation of High Stress Soft Rock Tunnel with Release-constraint Balancing Method

研究目的:高地应力软岩隧道大变形控制一直是隧道工程界的难题。我国兰渝铁路29座高地应力软岩隧道,施工中尽管应用了多种控制变形技术,但仍有近4 km地段发生了初期支护大变形侵限,被迫拆换钢架,从而给现场施工带来了极大的影响,因此,依托兰渝铁路研究高地应力软岩隧道大变形控制技术十分必要,它对保证工程质量,提高施工进度,确保施工安全有着重要的意义。研究结论:(1)对大变形风险进行评估是防范高地应力软岩隧道大变形的重要环节,评估内容包括高地应力软岩隧道地质分级、变形量计算和初期支护破坏准则制定三个方面;(2)释放-约束平衡法是针对高地应力软岩隧道特点,充分利用合理的预留变形量释放地应力,通过加强初支、强化锁脚、及时闭合、动态补强四个措施约束变形,经兰渝铁路工程检验,可有效地控制高地应力软岩隧道大变形。

Research purposes： It is difficult to control the large deformation of the high stress soft rock tunnel in the tunnel construction. The Lanzhou - Chongqing Railway has 29 high stress soft rock tunnels, and in spite of using a lot of technologies to control the deformation, but the large deformations still happened to the primary supports in the 4 kilometers long area and the rigid frames had to be replaced. The big deformations produced the big impact on the construction. So. It was necessary and important to do the research on the technology for control of the deformation of the high stress soft rock tunnel in order to guarantee the engineering quality, speed up the construction process and guarantee the construction security. Research conclusions： （ 1 ） To evaluate the danger of the large deformation is the important to prevent the large deformation of the high stress soft rock tunnel, and the evaluation content should include the three areas of the grading of the high stress soft rock tunnel, the deformation calculation and formulation of the responsibility for the failure of the primary support. （2） The release - constraint balancing method is used for releasing the ground stress by allowing deformation volume according to the features of the high stress soft rock tunnel and constraining the deformation by strengthening the primary support and lock pin, closing timely and dynamically reinforcing. The engineering application in the Lanzhou - Chongqing Railway shows this method is available for controlling the big deformation of the high stress soft rock tunnel.