基于声发射特征的覆岩采动裂隙演化规律研究

Study of the dynamic evolution rules of mining fracture based on acoustic emission technique

为研究覆岩采动裂隙演化过程能量释放规律,以构建的实验条件为基础,采用物理相似模拟、理论分析的方法,结合声发射技术,对覆岩采动裂隙演化过程中声发射特征进行了探讨。结果表明,采动裂隙演化过程是一个复杂的能量释放过程,模型开挖初期,覆岩损伤较小,声发射现象不明显,岩层移动变化较小,仅产生离层裂隙;在模型开挖中期,声发射现象越来越显著,即释放能量随来压次数显著升高,此时破断裂隙在纵向及横向不断发展;随着模型继续开挖,周期来压阶段内,声发射次数逐渐稳定,释放能量趋于稳定,此时破断裂隙纵向不再发展,仅随模型开挖在横向方向发展。

To study the law of energy release during mining fracture evolution,based on experimental conditions,through the methods of physical similar simulation and theoretical analysis,combined with acoustic emission technology,we studied acoustic emission characteristics during mining fracture evolution. Results show that it is a complicated process of energy dissipation for the dynamic evolution of mining fracture. During the initial stage of model excavation,the damage of overburden rock is feeble,and the acoustic emission is not obvious. The displacement of strata is small,only separation fractures appear; during the medium stage of model excavation,acoustic emission phenomenon is obvious with the increase of the times of periodic pressure,and broken fissures develop in the horizontal and vertical directions; with the excavation of model,during the periodic pressure,the receiving times of acoustic emission is stable gradually,energy dissipation also tends to be stable,and broken fissures develop only in the horizontal direction with the excavation of model.