摘要
为探究不同初始瓦斯压力下煤体循环冲击动力学特性及裂隙扩展规律,利用含瓦斯煤岩动静组合加载试验系统,对煤体开展不同初始瓦斯压力下循环冲击试验,获取含瓦斯煤在循环冲击载荷下的动态应力–应变曲线,分析循环冲击作用下煤体动力学参数与初始瓦斯压力的关系,并结合CT扫描技术对含瓦斯煤循环冲击前后裂隙扩展过程实现三维可视化与精细化定量表征。研究结果表明:(1)循环冲击载荷下含瓦斯煤动态应力–应变曲线基本相似,分为线弹性阶段、塑性阶段和卸载阶段3个阶段,冲击荷载下的煤体动力学参数随初始瓦斯压力增加均呈下降趋势,且初始瓦斯压力越大,瓦斯弱化侵蚀作用越强;(2)基于CT扫描提取的煤样破坏切片与重构的三维裂隙结果表明,冲击煤体中存在贯穿截面的环形平行裂纹和轴向劈裂贯通裂纹;通过含瓦斯煤二维、三维裂隙特征参数可以有效定量表征裂隙扩展过程,其表征参数均与初始瓦斯压力成正比;高瓦斯压力环境下煤体内部裂隙网络更加复杂,连通度更高,更易发生失稳破坏;(3)基于理论分析从瓦斯侵蚀作用和煤体内应力波传播角度揭示了煤体强度损伤劣化的原因,并结合瓦斯和动荷载对煤体产生的损伤效应,探讨了瓦斯作用下循环冲击煤体发生层裂破坏的原因。研究成果有助于丰富含瓦斯煤动力学理论,对矿井煤与瓦斯突出灾害的防治和预警具有一定的理论参考意义。
In order to explore the cyclic impact dynamic characteristics and crack propagation law of coal under different initial gas pressures,the cyclic impact test of coal under different initial gas pressures is carried out by using the combined dynamic and dynamic loading test system of coal-rock containing gas,and the dynamic stressstrain curve of gas-bearing coal under cyclic impact load is obtained.The relationship between coal dynamic parameters and initial gas pressure under cyclic impact is analyzed,3D visualization and fine quantitative characterization of crack propagation process before and after cyclic impact of gas-bearing coal are realized by CT scanning technology.The results show that:(1) the dynamic stress-strain curves of gas-bearing coal under cyclic impact load are basically similar,which are divided into three stages:linear elastic stage,plastic stage and unloading stage.The dynamic parameters of coal under impact load decrease with the increase of the initial gas pressure,and the greater the initial gas pressure,the stronger the gas weakening erosion effect.(2) Based on the fracture slices extracted by CT scanning and the reconstructed 3D fracture results,it is shown that annular parallel cracks and axial splitting through cracks exist in the impinged coal.The crack propagation process can be effectively and quantitatively characterized by two-dimensional and three-dimensional fracture characteristic parameters of gasbearing coal,and the characteristic parameters are proportional to the initial gas pressure.Under high gas pressure environment,the fracture network in coal body is more complex,the connectivity is higher,and the instability failure is more likely to occur.(3) Based on theoretical analysis,the causes of strength damage and deterioration of coal body are revealed from the perspective of gas erosion and internal stress wave propagation of coal body.Combined with the damage effect of gas and dynamic load on coal body,the causes of strapping failure of cyclic impact coal body under the action of gas are discussed.The research results are helpful to enrich the dynamic theory of gas-bearing coal and have a certain theoretical reference significance for the prevention and warning of coal and gas outburst disaster in mine.
作者
王磊
王安铖
陈礼鹏
李少波
刘怀谦
WANG Lei;WANG Ancheng;CHEN Lipeng;LI Shaobo;LIU Huaiqian(State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mine,Anhui University of Science and Technology,Huainan,Anhui 232001,China;School of Energy and Mining Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2023年第11期2628-2642,共15页
Chinese Journal of Rock Mechanics and Engineering
基金
安徽省科技重大专项项目(202203a07020010)
安徽高校协同创新项目(GXXT-2020-055)。
关键词
采矿工程
含瓦斯煤
循环冲击
动力学特性
CT扫描
裂隙扩展
mining engineering
gas-bearing coal
cyclic impact
dynamic characteristics
CT scan
crack propagation
