基于颗粒离散元的矿柱群连锁失稳机理分析

Mechanism of pillar's cascading failure based on discrete particle flow code

矿柱群连锁失稳是破坏后果最为严重的采空区失稳模式。本文利用颗粒流离散元PFC2D研究了矿柱群连锁失稳的动态过程以及不同的矿柱安全系数、不同的诱发位置、不同的顶板刚度对矿柱群连锁失稳的影响。结果表明:(1)矿柱群的连锁失稳从诱发矿柱开始,失稳矿柱的应力传递到相邻未失稳的矿柱上造成相邻矿柱失稳,由此引发连锁效应;(2)矿柱的储备安全系数与载荷传递量的相对关系是决定矿柱群是否发生连锁失稳的关键;(3)矿柱群大规模失稳与诱发位置有关,诱发矿柱位于采空区的中心位置更容易形成大规模失稳,而位于采空区的边界位置,由于边界矿柱约束支撑作用则不容易诱发大规模失稳;(4)顶板的刚度显著地影响矿柱群的连锁失稳过程,刚度小的软弱顶板条件下,载荷传递从诱发位置向空区边界依次传递,失稳过程具有显著的"多米诺骨牌效应",而刚度大的坚硬顶板条件下,载荷传递与矿柱失稳不再表现出显著的"多米诺骨牌效应"。本文的研究成果可供开展相关工作借鉴。

Pillar＇s cascading failure produces the most series consequences among all the likely failure modes of mined out area. The dynamic process of pillar＇s cascading failure was studied utilizing discrete particle flow code PFC2D. Besides,the influence of pillar＇s factor of safety,induced failure location,and roof stiffness on cascading failure were investigated as well. The following conclusions are obtained：（ 1） pillar＇s cascading failure initiates from the failure inducing pillar. Then load is transferred to next neighboring pillars which results in cascading failure;（ 2） the relation between the reserved factor of safety of pillars and the account of transferred load is critical to the occurrence of cascading failure;（ 3） pillar＇s cascading failure is affected by the inducing failure location. The failure of pillars which are located at central area of the goaf is more likely to induce cascading failure,while the failure of pillars located far away from the central area is less likely to induce cascading failure;（ 4） roof stiffness has significant influence on the process of cascading failure. When the roof is soft,the load will be transferred from one pillar to another successively,which shows typical domino effect. However,when the roof is hard,domino effect will no longer exist in the process of cascading failure.The research findings above can provide some guides to future work of goaf management.