摘要
研究目的:隧道围岩损伤的存在直接影响围岩的力学特性和稳定性,如果控制不当,将可能造成围岩失稳、塌方事故,因此必须掌握围岩损伤特性及其演化机理,进而为围岩损伤控制提供依据。本文基于微震监测的现场实测结果,揭示不考虑构造应力条件下隧道开挖引发的围岩损伤分区特性,采用应变软化模型并引入损伤力学理论,推导隧道围岩损伤区范围的表达式,并与实测结果进行对比,进一步分析围岩损伤特性的影响因素。研究结论:(1)围岩高损伤理论预测和实测结果具有较好的一致性,且围岩越差时,两者差异越小;(2)围岩损伤区半径随着脆性系数λ/E的增大而增大,随着黏聚力c和内摩擦角φ的减小而增大;围岩高损伤区半径随着极限损伤参数D_(cr)的增大而增大,且增速越来越快;(3)极限损伤参数D_(cr)和脆性系数λ/E除了与围岩自身参数相关外,也与支护手段有关,通过有效的支护手段,可以将围岩损伤极限参数控制在较低的水平下,从而确保高损伤区范围较小;(4)本研究成果可为隧道围岩损伤预测及支护设计提供依据。
Research purposes: The excavation damage of surrounding rock will inevitably affect the mechanical properties and stability of surrounding rock. When it is not controlled properly, failure or collapse accident may occur. Therefore, we must master the characteristics and evolution mechanism of surrounding rock damage, so as to provide basis for surrounding rock damage control and support design. Based on microseismic monitoring results, the damage characteristics of surrounding rock caused by tunnel excavation is revealed. The expression of damage zone is deduced by using strain softening model and damage mechanics theory without considering structural stress, which is compared with the measured results. The influencing factors of damage characteristics are further analyzed. Research conclusions:(1) The theoretical prediction results are in good agreement with the measured data, and when the worse the surrounding rock is, the smaller the error is.(2) The radius of surrounding rock damage zone increases with the increase of brittleness coefficient λ/E, and decreases with the decrease of surrounding rock cohesion c and internal friction angle φ. The radius of high damage zone of surrounding rock increases with the increase of ultimate damage parameter D_(cr) with the growth rate faster.(3) The ultimate damage parameter D_(cr) and brittleness coefficient λ/E are not only related to the parameters of surrounding rock itself, but also related to the support means.(4) The research results can provide reference for the prediction and safety control of excavation damage of surrounding rock.
作者
李奥
张顶立
黄俊
董飞
孙振宇
侯艳娟
LI Ao;ZHANG Dingli;HUANG Jun;DONG Fei;SUN Zhenyu;HOU Yanjuan(JSTI Group,Jiangsu Province Engineering Research Center of Underwater Tunnel Green Intelligent Technology,Nanjing,Jiangsu 210029,China;Key Laboratory for Urban Underground Engineering of Ministry of Education,Beijing Jiaotong University,Beijing 100044,China)
出处
《铁道工程学报》
EI
北大核心
2022年第11期63-69,共7页
Journal of Railway Engineering Society
基金
国家自然科学基金(51738002)
住建部科技项目(2019-K-110)。
关键词
围岩开挖损伤
损伤力学
应变软化
损伤范围
极限损伤参数
excavation damage of surrounding rock
damage mechanics
strain softening
damage range
ultimate damage parameter
