School of Civil Engineering, Henan Polytechnic University
2 Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization, Henan Polytechnic University
Jiaozuo Normal College

为了进一步提高硬性花岗岩岩爆倾向性预测水平,系统开展了花岗岩巴西劈裂、单/三轴和不同卸围压速率应力路径下的岩石力学试验,详细分析了花岗岩强度和岩爆倾向性特征。研究结果表明:花岗岩在主应力σ3–σ1平面内,不同应力路径下的强度受围压和卸围压速率影响显著,呈带状分布;在τoct–(σ1+σ3)/2平面内,不同加卸载应力路径下的强度都呈良好的线性特征。据此建立了花岗岩八面体强度计算通式,可统一表达不同加卸载应力路径;针对花岗岩硬岩的压密和屈服特性不明显,弹性特性显著的特征,提出了简化剩余弹性能指数岩爆分级法;并依据花岗岩试验岩样破坏形态和破坏声学特征,对已有花岗岩岩爆等级进行了细分。揭示了在相同初始围压下,卸围压速率越大,简化剩余弹性能指数越大,岩爆倾向性越强;相同卸围压速率下,初始围压越大,简化剩余弹性能指数也越大,岩爆倾向性也越强。研究成果可为更科学合理的评估花岗岩岩爆倾向性提供理论参考。

In order to improve the prediction accuracy of rockburst proneness of hard granite, the rock mechanics tests were carried out under Brazilian splitting, uniaxial, triaxial and different unloading confining pressure rates, and the characteristics of granite strength and rockburst proneness were systematically analyzed. It is found that the strength of granite in σ3–σ1 plane is significantly affected by the confining pressure and the rate of unloading confining pressure, distributed in a band zone. In τoct–(σ1+σ3)/2 plane, the strength under different loading and un-loading stress paths shows good linear characteristics, and a general formula for calculating the octahedral strength of granite under loading and different unloading rates was obtained. According to the characteristics of hard granite that the compression and yield stages are not significant but the elastic stage is significant, a rock-burst classification method of the simplified residual elastic energy index was proposed. The rockburst grade of granite was subdivided on the basis of rockburst classification in existing literature according to the failure mor-phology and acoustic characteristics of granite samples. Under the same initial confining pressure, the larger the unloading rate of confining pressure is, the larger the simplified residual elastic energy index is, and the rockburst proneness becomes stronger. At the same unloading rate of confining pressure, the larger the initial confining pressure is, the larger the simplified residual elastic energy index is, and the rockburst proneness becomes stronger. The research results lay a theoretical foundation for a more scientific and reasonable evaluation of the rockburst proneness of granite.

国家自然科学基金资助项目(U1604142);河南省重点研发与推广专项资助项目(232102320350;222102320410)

王云飞,宋梦怡,焦华喆,等.加卸载花岗岩强度与岩爆倾向性试验研究[J].采矿与岩层控制工程学报,2024,6(3):033035.

WANG Yunfei, SONG Mengyi, JIAO Huazhe, et al. Experimental study on strength and rockburst proneness of granite under loading and unloading[J]. Journal of Mining and Strata Control Engineering, 2024, 6(3): 033035.