Caving-induced fault reactivation and its effects on caving process are widely recognized as serious safety issues in mining and tunnelling industry. In this study, the effects of a variety of factors (i.e. friction coefficient, stick–slip instability, geological structure, pre-mining status, mining and its induced effects) that might exert an influence on fault dynamic behaviour of a 5-seam coal mine are investigated using practical mine-wide finite element numerical models with a normal fault. Based on the research outcomes on R-minimum-based finite element modelling of earthquake dynamics, the node-to-point contact strategy and the nonlinear friction contact law have been used here to simulate and analyse the caving-induced stick–slip frictional instability along the fault and related effects. The simulation results show that: (1) stress distribution before mining is relatively uniform around the fault for a homogenous rock material case, while stress concentration appears around the fault for the model with contrasting rock material properties; (2) the multiple-layered models are in favour of fault reactivation than models with only one material for whole strata; (3) the fault reactivation scale (i.e. dynamic relative motion and fault slip) induced by caving activity is significantly affected by rock mass strength, caving depth and its relative position to the fault. As caving progresses deeper and closer to the fault, the fault reactivation scale increases. Meanwhile, the fault in low strength strata is much more sensitive to fault slip behaviour; (4) seismic source parameters, namely seismic moment and moment magnitude, are adopted to evaluate the magnitude of caving-induced seismicity based on numerical results and fault slip risk and magnitude increase as fault reactivation scale expands; (5) during the caving stage, the failure zone initiates, develops and eventually connects the reactivated fault to the working area, presenting asymmetric failure pattern around the caving zone. The failure zone is obviously larger for the side closer to the fault than the other side due to caving-induced fault reactivation effects. This could help in better understanding fault reactivation and rock failure behaviours towards an optimised design of caving in a faulted region.

开采引起的断层再活化及其对开采过程的影响已被广泛认为是采矿和隧道业的严重安全问题。在这项研究中，多种因素的影响（例如，摩擦系数，粘滑失稳，地质结构，开采前的状况，采矿及其诱发的影响）可能会影响5缝煤的断层动力学行为。使用具有正常断层的实用全矿井有限元数值模型对矿井进行了研究。基于基于R最小值的地震动力学有限元建模的研究成果，这里使用了节点到点接触策略和非线性摩擦接触定律来模拟和分析崩落引起的粘滑摩擦不稳定性。故障及其相关影响。仿真结果表明：（1）对于均质的岩石材料情况，断层周围的开采前应力分布相对均匀，而对于岩石材料特性相反的模型，应力集中出现在断层周围。（2）多层模型比整个层仅用一种材料的模型更有利于断层再激活。（3）崩落活动引起的断层复活尺度（即动态相对运动和断层滑动）受岩体强度，崩落深度及其相对于断层的相对位置的显着影响。随着崩落越来越深，越接近断层，断层再激活规模越大。同时，低强度地层中的断层对断层滑动行为更为敏感。（4）震源参数，即地震矩和矩震级，根据数值结果和断层滑移风险以及随着断层再激活规模的扩大而增加，来评估崩落诱发地震的强度。（5）在崩落阶段，破坏带开始，发展并最终将重新活化的断层连接到工作区，在崩塌带周围呈现出不对称的破坏模式。由于崩落引起的断层再激活效应，靠近断层的一侧的故障区域明显大于另一侧。这可能有助于更好地理解断层的复活和岩石破坏行为，从而优化断层区域的崩落设计。形成并最终将重新激活的断层连接到工作区域，从而在崩落带周围呈现出不对称的破坏模式。由于崩落引起的断层再激活效应，靠近断层的一侧的故障区域明显大于另一侧。这可能有助于更好地理解断层的复活和岩石破坏行为，从而优化断层区域的崩落设计。形成并最终将重新激活的断层连接到工作区域，从而在崩落带周围呈现出不对称的破坏模式。由于崩落引起的断层再激活效应，靠近断层的一侧的故障区域明显大于另一侧。这可能有助于更好地理解断层的复活和岩石破坏行为，从而优化断层区域的崩落设计。