特大断面砂质板岩隧道Ⅴ级围岩变形时空效应

为探明特大断面砂质板岩隧道Ⅴ级围岩时空效应规律,进而为类似隧道工程提供系统性借鉴,通过现场监控量测及大数据回归分析方法研究特大断面砂质板岩隧道Ⅴ级围岩变形时空效应。结果表明:隧道开挖,施做初期支护后,拱顶沉降及洞室围岩水平收敛过程分为3个阶段,分别为急剧变形阶段、缓慢变形阶段、稳定阶段;隧道开挖,施做初期支护25 d后,是施做二次衬砌最佳时机;隧道结构体系与掌子面空间距离约3倍洞径时,是施做二次衬砌最佳时机,且Ⅴ级围岩二衬距离掌子面距离不应大于50 m。

Temporal and Spatial Effects of V-Type Surrounding Rock Deformation in Extra Large Section Sandy Slate Tunnel

In order to find out the space-time effect law of the V-class surrounding rock of the super-large cross-section sandy slate tunnel, and provide a systematic reference for similar tunnel projects, this paper studied the space-time effect of V-grade surrounding rock deformation of super-large section sandy slate tunnel through field monitoring measurement and large data regression analysis method. The results show that: The results show that: (1) the process of vault settlement and horizontal convergence of surrounding rock can be divided into three stages: rapid deformation stage, slow deformation stage and stable stage; (2) tunnel excavation, 25 days after initial support, is the best time for secondary lining; (3) the space distance between tunnel structure system and face is about three times the diameter of tunnel. It is the best time to make secondary lining, and the distance between the second lining of grade V surrounding rock and the face should not be greater than 50m; (4) the time history curve equation of settlement and convergence of grade V surrounding rock vault of super-large section sandy slate tunnel is y = 2.611ln (1 + x), y = 3.262ln (1 + x); (5) the space curve equation of settlement and convergence change of grade V surrounding rock vault of super-large section sandy slate tunnel is divided. They are y = 2.404ln (1 + x) and y = 2.68ln (1 + x).