1. School of Mechanics & Civil Engineering,China University of Mining and Technology(Beijing),Beijing　 100083,China;2. State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology(Beijing),Beijing　 100083,China;3. School of Mining Engineering,Heilongjiang Uni-versity of Science and Technology,Harbin　 150022,China

通过MTS815试验机对钱家营矿煤-岩组合体进行常规三轴压缩试验。研究表明:围压作用下煤-岩组合体压密阶段较短,具有明显的线弹性及塑性屈服阶段,且随着围压的增大,峰后延性特征明显;根据峰值应变、弹性模量、破断角、强度的变化规律,10~15 MPa为组合体变形减缓的临界区间;煤样破坏主要以单斜面剪切破坏为主,并且个别岩体部分产生与煤样一致的剪切面,破断角处于14.1°~38.8°,均值为26.84°与理论破断角28.31°相差不大;随着围压的增大,残余强度有增高趋势,岩石强度衰减系数与之相反。围压从0~5 MPa,强度衰减系数降幅最大,体现出对围压的敏感性,随后围压继续升高,强度衰减系数呈线性递减;利用Hoek-Brown和广义HoekBrown准则对煤-岩组合体强度进行分析,讨论了适用于煤-岩组合体的参数m,s值。

A testing system MTS 815 was used to carry out triaxial compression test for Qianjiaying coal-rock combined body. The results show that the consolidation stage is shorter and it apparently has a linear elastic stage and a plastic yield stage under the influence of confining pressure. Ductility of post-peak stage is much more apparent with the in- crease of confining pressure. Based on the change laws of peak strain,elastic modulus,rupture angle and strength,the threshold confining pressure of deformation is 10-15 MPa. The failure mode of coal body is mainly shear failure,and some rock bodies have the same failure mode with coal body. The rupture angle is within the range of 14. 1°-38. 8°and its average value is 26. 84° which has little difference with 28. 31° calculated using Coulomb strength criterion. Residual strength has an increasing trend with the increase of confining pressure while rock Ds has the opposite trend. From 0 to 5 MPa,the decreasing range of Ds is the largest which reflects the sensibility to confining pressure. Then, with the increase of confining pressure,Ds shows a linear decrease. Finally,the values of m,s in Hoek-Brown and gen- eralized Hoek-Brown failure criterion are discussed.

国家自然科学基金资助项目(51374215,11572343)；北京市科委重大科技成果转化落地培育资助项目(Z151100002815004)；

Zuo Jianping,Chen Yan,Zhang Junwen,et al. Failure behavior and strength characteristics of coal-rock combined body under different con- fining pressures[J]. Journal of China Coal Society,2016,41(11):2706-2713.