铁路隧道双指标高地应力界定及岩爆大变形分级标准

Definition for Dual-index High Geostress and Classification Standard for Rock Burst and Large Deformation in Railway Tunnels

研究目的:目前国内外针对高地应力环境隧道岩爆大变形分级的判识以理论研究为主,结果与实际施工开挖后多有出入。因此,本文通过总结78个铁路、公路隧道和水电站引水隧洞工程案例,对隧道围岩的高地应力状态及岩爆大变形分级界定进行系统研究,结合目前实际工程中采用的隧道相关设计规范,对传统高地应力判识标准及岩爆、大变形分级标准进行优化,提出更符合工程实际的定量界定方法。研究结论:(1)基于工程案例统计分析,建立了采用强度应力比和最大地应力绝对值的双指标高地应力定量界定方法,提出了分别针对硬质岩和软质岩的双指标高地应力定量判识表;(2)提出以岩石强度应力比R/σ_(max)和最大地应力σ_(max)双指标的岩爆等级划分标准,提出以岩体强度应力比R_(m)/σ_(max)和最大地应力σ_(max)双指标的大变形等级划分标准;(3)本研究成果可应用于铁路隧道围岩高地应力状态的判识和灾害等级的划分,适用于工程地质勘察领域。

Research purposes:At present,the classification of large deformation of rock burst in tunnels with high geostress environment is mainly based on theoretical research,and the results are different from the actual construction and excavation.Therefore,by summarizing 78 cases of railway,highway tunnels and hydropower diversion tunnel projects,this paper systematically studies the high geostress state of the tunnel surrounding rock and the classification and definition of the large deformation of rock burst.Combined with the relevant tunnel design specifications adopted in current practical projects,the traditional high geostress identification standard and the rock burst and large deformation classification standard are optimized,and a quantitative definition method that is more in line with the actual engineering is proposed.Research conclusions:(1)Based on the statistical analysis of engineering cases,a dual-index high geostress quantitative definition method using the strength-stress ratio and the maximum geostress absolute value is proposed,and a dual-index high geostress quantitative identification table for hard rock and soft rock is proposed.(2)A rock burst grade classification standard based on the rock strength-stress ratio R/σ_(max)and the maximum geostressσ_(max)is proposed,and a large deformation grade based on the rock mass strength-stress ratio R_(m)/σ_(max)and the maximum geostressσ_(max)is proposed.(3)The research results can be applied to the identification of the high geostress state of the surrounding rock of railway tunnels and the classification of disaster grades,and are suitable for the field of engineering geological survey.