深部高应力煤巷围岩径向梯度损伤特征试验研究  

Experimental study on radial gradient damage characteristics of surrounding rock in deep high stress coal roadway

作　　者：朱永建[1,2,3] 李鹏 王平 任恒[2] 陶玮 梅成成 王希之 ZHU Yongjian;LI Peng;WANG Ping;REN Heng;TAO Wei;MEI Chengcheng;WANG Xizhi(Work Safety Key Lab on Prevention and Control of Gas and Roof Disasters for Southern Goal Mines,Hunan University of Science and Technology,Xiangtan,Hunan 411201,China;School of Resource and Environment and Safety Engineering,Hunan University of Science and Technology,Xiangtan,Hunan 411201,China;Hunan Provincial Key Laboratory of Safe Mining Techniques of Coal Mines,Hunan University of Science and Technology,Xiangtan,Hunan 411201,China)

机构地区：[1]湖南科技大学南方煤矿瓦斯与顶板灾害预防控制安全生产重点实验室,湖南湘潭411201 [2]湖南科技大学资源环境与安全工程学院,湖南湘潭411201 [3]湖南科技大学煤矿安全开采技术湖南省重点实验室,湖南湘潭411201

出　　处：《岩石力学与工程学报》2023年第11期2643-2654,共12页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金面上项目(52274119);湖南省自然科学基金面上项目(2021JJ30273);湖南科技大学煤矿安全开采湖南省重点实验室开放基金项目(969-E22227)。

摘　　要：为了研究深部回采煤巷开挖扰动引起的围岩径向梯度损伤特征,以平顶山十一矿深井工程为背景,对现场煤样开展不同围压条件下三轴压缩试验和三轴损伤试验,结合三轴压缩轴向应力–应变曲线研究煤样的变形特征;利用MATLAB软件识别并分析三轴损伤煤样的破裂特征。结果表明:轴向应力达到屈服强度后,煤样出现明显的应变软化特性,峰值应力与残余强度随围压呈线性增长,利用M-C强度准则计算出煤样黏聚力c=10.19 MPa,内摩擦角φ=27.26°。煤样表面裂纹对轴压敏感度较高,轴压越大,煤样表面裂纹越复杂,围压的增加在一定程度上可以抑制表面裂纹的扩展,但最终都会向剪切破裂面发展。基于岩石损伤变量服从Weibull分布的特点,理论推导了常规三轴下的煤样损伤软化本构模型,结合三轴损伤煤样应力–应变变化关系,采用线性拟合方法对模型参数F0和m进行修正,最终得到了修正的煤样损伤软化本构模型,并基于试验数据验证了修正模型的可靠性。此外,在修正后的煤样损伤软化本构模型基础上对弹性区、塑性软化区以及破碎区围岩应力、应变的关系式展开讨论,建立了一种巷道围岩径向梯度损伤程度的计算方法。In order to study the radial gradient damage features of the surrounding rock caused by the excavation disturbance of the deep back mining coal tunnel.With the background of the deep shaft project of Pingdingshan Eleven Mine,triaxial compression tests and triaxial damage tests were carried out on the on-site coal samples under different circumferential pressure conditions,and the deformation characteristics of the coal samples were studied by combining the triaxial compression axial stress-strain curves;the rupture characteristics of the triaxially damaged coal samples were identified and analyzed by using MATLAB software.The results showed that after the axial stress reached the yield strength,the coal sample showed obvious strain softening characteristics,the peak stress and residual strength increased linearly with the surrounding pressure,and the c of the coal sample was calculated to be 10.19 MPa and φ was 27.26° using the M-C strength criterion.The surface cracks of coal samples are sensitive to the axial pressure,and the larger the axial pressure is,the more complex the surface cracks of coal samples are.The increase of circumferential pressure can inhibit the expansion of surface cracks to a certain extent,but they will all eventually develop toward the shear rupture surface.Based on the characteristics of rock damage variables obeying Weibull distribution,the softening intrinsic model of coal sample damage under conventional triaxial was derived theoretically,and the model parameters F0 and m were modified by linear fitting method in combination with the stress-strain variation relationship of triaxially damaged coal samples,and finally the modified softening intrinsic model of coal sample damage was obtained,and the reliability of the modified model was verified based on experimental data.In addition,the relationship equations of stress and strain in the elastic zone,plastic softening zone and fracture zone of the surrounding rock are discussed on the basis of the modified damage softening intrinsic m

关 键 词：采矿工程 深部高应力 应变软化 损伤本构模型 双向等压 径向梯度损伤 

分 类 号：TD32[矿业工程—矿井建设]