【摘要】 在丽香铁路中义隧道围岩及初期支护变形、破坏特点归纳总结的基础上,结合隧道的区域地质条件,分析了围岩大变形的形成机制。研究表明:丽香铁路中义隧道围岩及初期支护变形、破坏特点是由隧址区地应力最大主应力为水平方向且与隧道轴线接近垂直的特点决定的;围岩大变形主要是由于隧址区强烈的地质构造使围岩完整性遭受严重破坏,围岩破碎,地层赋存较高的构造残余应力引起的。现场实验及施工实践表明:按围岩的工程地质条件、强度应力比及相对位移将大变形分级管理,根据大变形级别选用不同的衬砌断面、支护参数和预留变形量;采用上下台阶、下台阶带仰拱一次开挖方法施工,适当加长边墙系统锚杆和锁脚锚杆,适时进行初期支护补强。更多还原

【Abstract】 Based on the conclusion that deformation and destruction characteristics of between tunnel rock mass, and combined with the regional geological conditions of the tunnel, this paper analyzed the formation mechanism of large deformation of surrounding rock. Research results show that the maximum principal stress in tunnel zone is horizontal and the stress is nearly perpendicular to the tunnel axis, which determines the characteristics of deformation and destruction between tunnel surrounding rock and primary support. The strong geological structure of the tunnel zone seriously damages the integrity of surrounding rock, the fragmentation of surrounding rock, and the high tectonic residual stress in the stratum, these factors mainly caused the large deformation of surrounding rock. Field experiment and site operation show that effective measures to control large deformation of surrounding rock are as follows. According to the engineering geological conditions, strength-stress ratio and relative displacement of surrounding rock, large deformation classification is good for the management. At different lining section, supporting parameters and deformation allowance could be determined according to the large deformation grade. By using the construction method of the up-and-down bench and lower bench one-time excavation with inverted arch, properly lengthening system anchor bolt on the wall and feet-lock bolt, timely strengthening initial support.更多还原