摘要
为揭示不同应力环境巷道开挖扰动应力重分布特征及能量演化机制,利用离散元PFC程序建立半圆拱泥岩巷道模型,获取巷道围岩宏观应力场及全断面变形动态演化曲线,以巷道开挖细观应力场分布特征为基础,揭示巷道开挖声发射特性及能量演化一般规律,探究垂直应力和侧压系数对不同能量特征的影响,并以应变能释放速率作为表征巷道开挖能量释放严重程度的指标。结果表明:巷道开挖后围岩径向应力和切向应力均经历"卸压—回升—波动—稳定"4个阶段,卸压阶段应力快速释放,且越靠近临空面,应力释放越剧烈。拱顶不同深度测点径向应力和切向应力模拟值与解析解比较吻合,表明模拟结果能够较好地反映巷道开挖后围岩不同深度应力分布规律。λ=1.0时,巷道最大位移量与垂直应力近似呈线性正相关。颗粒黏结力、线性力等细观接触力随垂直应力及侧压系数增加而增大。开挖扰动期间裂纹主要产生在应力升高阶段,集中在巷道底角及拱顶等处。围岩应变能、动能、摩擦能随垂直应力和侧压系数增加而增大,在相同侧压系数下应变能与垂直应力平方成正比,定量揭示了应变能与垂直应力关系。应变能释放速率随围岩应力水平增加而增大,反映出高应力巷道应变能释放更加剧烈,导致围岩动能和摩擦能显著增加。
In order to reveal the disturbance stress redistribution characteristics and energy evolution mechanism of roadway excavation under different stress environments,the semi-circular arch mudstone roadway model is established by discrete element program of PFC,and the dynamic evolution curve of macroscopic stress field and full-section deformation of the roadway surrounding rock are obtained.Based on the distribution characteristics of micro-stress field,the general law of acoustic emission and energy evolution of roadway excavation is revealed.The influence of confining pressure and lateral pressure coefficient on different energy characteristics is explored,and the strain energy release rate is used to characterize the excavation energy release.The results show that after the roadway excavation,the radial stress and the tangential stress all go through four stages:"pressure relief-recovery-fluctuation-stability".In the pressure relief stage,the stress is released rapidly,and the closer to the free surface,the more intense the stress release.The simulation results of radial stress and tangential stress at different depths of the vault are in good agreement with the analytical solution,which shows that the simulation results can better reflect the stress distribution law of the surrounding rock after the roadway excavation.When λ=1.0,the maximum displacement of the roadway is approximately linearly positively correlated with the vertical stress.The micro contact forces such as particle adhesion force and linear force increase with the increase of vertical stress and lateral pressure coefficient.During the excavation disturbance,the cracks are mainly produced in the stage of stress increase,concentrated at the bottom corner of the roadway and the vault.The strain energy,kinetic energy and friction energy of surrounding rock increase with the increase of vertical stress and lateral pressure coefficient.Under the same lateral pressure coefficient,the strain energy is proportional to the square of the confining pressure.The relationship between strain energy and confining pressure is quantitatively revealed.The release rate of strain energy increases with the increase of surrounding rock stress level,which indicates that the release rate of strain energy in high stress roadway is more intense,which leads to the significant increase of surrounding rock kinetic energy and friction energy.
作者
于辉
张晓君
李宝玉
褚夫蛟
YU Hui;ZHANG Xiaojun;LI Baoyu;CHU Fujiao(School of Energy Science and Engineering,Henan Polytechnic University,Jiaozuo 454000,China;School of Resources and Environmental Engineering,Shandong University of Technology,Zibo 255000,China;State and Local Joint Engineering Laboratory for Gas Drainage&Ground Control of Deep Mines,Henan Polytechnic University,Jiaozuo 454000,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2020年第S01期60-69,共10页
Journal of China Coal Society
基金
深井瓦斯抽采与围岩控制技术国家地方联合工程实验室开放基金资助项目(SJF201807)
山东省自然科学基金资助项目(ZR2018PEE003)
关键词
巷道
应力重分布
能量演化
离散元
roadway
stress redistribution
energy evolution
discrete element
