深部金属矿采场顶板滑移冒落微震时空演化规律

Temporal and Spatial Characteristics of Microseismic Events During Roof Sliding Caving in Deep Metal Mine

针对阿舍勒铜矿深部采场顶板滑移性破裂过程中的微震时空演化、灾害孕育诱发因素与发生机制进行了系统研究。结果表明:微震时空分布可以直观反映岩体内部裂纹的演化过程;采场冒落前,微震活动性出现明显减弱现象,但微震能量呈现幂率加速释放态势;在所监测的微震事件中,剪切型破裂占比达68%,且主要集中于矿岩接触带处,顶板则为张拉型破裂为主的非剪切破坏区。采场顶板滑移性冒落是接触带两侧矿岩体物理力学性质差异性和附近采场强烈回采爆破扰动共同作用造成的。在进行深部金属矿体边界区域回采时,应加强地压灾害孕育发生过程的实时监测,并采用及时充填和减小爆破扰动等措施,降低采场顶板冒落风险。

The inducing factors and occurrence mechanism of the roof sliding caving were studied by analyzing the temporal and spatial characteristics of microseismic events in Ashele Copper Mine.The results showed that the evolution of microseismic events directly reflects the changes of internal cracks in rock mass.Before the caving,the microseismic activity was obviously weakened,but the radiated energy was accelerated released according to a power law.In the monitored microseismic events,shear cracks play a dominant role,accounting for 68%of the total events,and are mainly concentrated in the ore-rock contact zone.To the contrary,the roof is the non-shear failure zone dominated by tensile fracture.The caving is caused by the combined action of the difference of physical and mechanical properties of rock mass on both sides of the contact zone and the strong blasting disturbance from nearby stope.When mining the boundary area of metal orebody,it is necessary to real-time monitor the rock mass stability and adopt measures such as timely filling and reducing blasting disturbance to weaken the risk of ground pressure disaster.