含双圆孔煤样渐进性破坏的孔周表面变形及裂隙演化特征  

Characteristics of borehole surface deformation and fracture evolution in progressively demaged coal samples containing double circular boreholes

作　　者：张航 张天军 纪翔[1] 季冰 纪丙楠 庞明坤 潘红宇 ZHANG Hang;ZHANG Tianjun;JI Xiang;JI Bing;JI Bingnan;PANG Mingkun;PAN Hongyu(College of Safety Science and Engineering,Xi’an University of Science and Technology,Xi’an 710054,China;Key Laboratory of Western Mine Exploitation and Hazard Prevention of the Ministry of Education,Xi’an 710054,China)

机构地区：[1]西安科技大学安全科学与工程学院,陕西西安710054 [2]西部矿井开采及灾害防治教育部重点实验室,陕西西安710054

出　　处：《煤炭学报》2024年第8期3468-3483,共16页Journal of China Coal Society

基　　金：国家自然科学基金资助项目(52374228,51874234,52274226)。

摘　　要：瓦斯预抽钻孔和防冲卸压钻孔协同布置能够一体化防治矿井冲击地压和瓦斯复合灾害,但密集布孔可能会诱发串孔、塌孔等,影响矿井瓦斯抽采效率。为了探究这类双钻孔结构煤岩体受压破坏过程中孔周表面变形及其裂隙演化规律,利用煤岩变形破坏数字图像观测系统对含双圆孔煤样开展单轴压缩条件下的3D-DIC观测实验,获取了不同应力状态下试样表面变形的时间序列图像,通过三维表面重构技术和VIC^(3D)分析处理软件计算得到了试样表面三维全场变形,根据应变场分析结果结合统计指标分析法对应力应变曲线进行了5个变形阶段划分,精细化表征了孔周表面变形和裂隙演化特征。研究结果表明:单轴压缩下含双圆孔煤样应变场灰度整体向高灰度级方向移动,应变场灰度直方图谱峰占比以应力峰值为界先缓慢变化再快速变化;试样孔周径向位移曲线呈现出“从”字型,环向位移曲线呈现出“人”字型,且左孔H_(1)孔周始终沿逆时针方向加速移动,右孔H_(2)孔周始终沿顺时针方向加速移动;孔周裂隙以逆时针错动为主,并伴随着少数裂隙的顺时针错动;应变局部化带外区在加载峰值前主要体现为能量累积,加载峰值后主要表现为能量释放,同时也伴随着部分能量调整转移造成的能量累积;在试样加载过程中,应力场环境、裂隙端部几何形状以及裂隙长度不断发生变化,造成裂隙尖端的应力强度因子K_(Ⅰ)减小,存在阻碍裂隙扩展的作用。The coordinated arrangement of gas pre-drainage boreholes and anti-impact and pressure relief boreholes can integrate the prevention and control of mine rock burst and gas compound disasters.However,the dense arrangement of these boreholes may lead to the occurrence of phenomena such as string holes and collapse holes,which could potentially impact the efficiency of mine gas extraction.To investigate the deformation around borehole surface and the evolution of fractures during the compression failure process in the coal and rock masses with dual borehole structure,the 3D-DIC observation experiment was conducted on the coal samples containing double circular holes under uniaxial compression con-ditions using a digital image observation system for coal rock deformation and failure. This experiment yielded some time-series images of sample surface deformation under various stress states. The three-dimensional full-field deformation of the sample surface was calculated using the three-dimensional surface reconstruction technology and VIC^(3D) analysis pro-cessing software. Based on the results of strain field analysis, the stress-strain curve was divided into five deformation stages using statistical index analysis methods, providing a detailed description of the deformation and fracture evolution characteristics around the borehole surface. The results show that under uniaxial compression, the grayscale of strain field in the coal samples with double circular holes shifts toward higher gray levels. The proportion of peaks in the strain field gray histogram changes slowly at first and then rapidly, with the peak stress serving as the boundary. The radial displace-ment curve around the sample holes presents a “从” shape, while the circumferential displacement curve presents a “人” shape. The left hole H_(1) always accelerates counterclockwise, while the right hole H2 always accelerates clockwise. The fractures around the holes are primarily characterized by counterclockwise dislocation, accompanied by a few

关 键 词：渐进性破坏 裂隙演化 孔周位移 裂隙张开错动 应变能演化 

分 类 号：TD712[矿业工程—矿井通风与安全]