高地应力断层带软岩隧道变形特征与控制措施研究

隧道在穿越断层地带时由高地应力引起的软岩大变形问题是隧道建设施工中难点，给隧道建设的施工与进度带来很大影响。本文结合区域地应力，围岩强度实验等分析柿子园隧道穿越断层地区产生支护结构破坏现象的原因，并对围岩压力，钢架应力，围岩变形进行了现场监测，得到了高地应力软岩大变形引起的支护应力特征与变形特征，提出了控制大变形的技术措施。研究表明,高地应力区软岩隧道穿越断层地带时，由于复杂的构造应力造成隧道结构受力不均，隧道左右两侧围岩压力，支护内力与围岩变形呈现出很大的不对称性。采用优化断面形式、加强初支刚度、非对称预留变形量和锚杆布置等措施可以有效减小隧道结构受力，控制隧道变形。

Study on large deformation characteristics and control measures of soft rock tunnel in fault zone with high geostress

The problem of large deformation caused by tectonic stress has been a common and difficult problem in tunnel construction when soft rock tunnels cross fault zone with high geostress, which has great influence on the construction and progress of tunnel construction. In this paper, taking Shiziyuan tunnel along Chenglan railway as engineering background, the reasons of the failure of the supporting structure of tunnel crossing the fault area are analyzed by combining the regional ground stress and the surrounding rock strength test, and the surrounding rock pressure, the stress of the steel frame and the deformation of the surrounding rock are monitored. The characteristics of the supporting stress and deformation caused by the large deformation of the soft rock are analyzed, and the technical measures to control the large deformation are put forward. Due to the complex tectonic stress, the stress of the tunnel structure is uneven, and the surrounding rock pressure, supporting stress and deformation of the surrounding rock show great asymmetry when soft rock tunnels cross fault zone with high geostress. It is possible to reduce the stress of the tunnel structure and control the deformation of the tunnel by optimizing the cross section, strengthening the initial stiffness, the asymmetric reserve deformation and the anchor arrangement.