School of Energy Science and Engineering, Henan Polytechnic University
School of Emergency Management and Safety Engineering, North China University of Science and Technology
Gengcun Coal Mine, Henan Dayou Energy Co Ltd

为研究冲击倾向性煤层巷道底板煤岩体的动态力学特性,利用分离式霍普基森压杆(SHPB)试验系统,采用耿村煤矿综放开采回采巷道的煤样和底板岩样,进行圆柱形组合煤岩样动静载荷冲击压缩试验,研究煤岩组合比、冲击速度和围压对组合煤岩样动态力学性能的影响。试验结果表明:依据动态应力-应变曲线,将煤岩样冲击压缩变形过程划分为4个阶段,在屈服阶段煤岩样变形出现数次应力屈服平台;试件动态抗压强度、屈服强度均与煤岩组合比负相关,煤岩样动态峰值强度、变形模量、极限应变等均与冲击速度呈线性正相关,动态峰值应变、极限应变和残余应变均与围压负相关。基于统计损伤理论,建立三维中应变率组合煤岩样黏弹性时效损伤本构关系。理论曲线与室内试验曲线拟合度较高,可用来表示三轴动静载作用下组合煤岩样动态应力-应变关系。研究结论为冲击地压矿井深部开采时煤岩样变形失稳机理研究提供理论支撑。

In order to study the dynamic mechanical properties of coal-rock mass in gateway floor of im- pact-prone coal seam, the impact compression tests of cylindrical coal-rock combined specimens (CRCS) under dynamic and static loads are carried out with the coal samples and floor rock samples from the gateway at fully mechanized caving face of Gengcun Coal Mine by the split Hopkinson pressure bar (SHPB) test system. The effects of coal-rock combination ratios, impact velocities, and confining pressures on the dynamic mechanical properties of CRCS are studied. The test results show that the im-pact compression deformation process of CRCS can be divided into four stages according to the dynamic stress-strain curves. Several yield platforms appear in the deformation of CRCS during their yield stages. The dynamic compressive strength and yield strengths of CRCS have a exponential negative correlation with the coal-rock combination ratios. The dynamic peak strength, deformation modulus and ultimate strain of CRCS have a positive linear correlation with impact velocities. The dynamic peak strain, ulti- mate strain and residual strain are negatively correlated with confining pressures. Based on the statistical damage theory, the viscoelastic aging damage constitutive relationship of CRCS under three-dimensional and medium strain rates is established. The fitting degree between the theoretical and the experimental curves is so high that theoretical curves can be used to represent the stress-strain relationship of CRCS under triaxial impact compression. The conclusions provide a theoretical support for the study of deform- ation and instability mechanism of CRCS during deep mining in coal bump mines.

国家自然科学基金项目(51574110,52074102);河北省高等学校科学技术研究项目(QN2024057);河南省重点研发与推广专项项目(222102320143)