Rockslides are among the most dangerous geohazards. The discrete element method (DEM) has been increasingly used to simulate the emplacement process of rockslides. However, few studies have modeled the fragmentation of jointed rock masses during movement via DEM simulations and verified the reliability of the results through comparison with the results of laboratory experiments and field events. In this paper, a series of DEM simulations based on PFC3D5.0 was conducted to replicate laboratory experiments in which breakable blocks with different structural forms impact and slide on a horizontal plane and experience fragmentation. The results show that the DEM model provides first-order estimates that are comparable with the results of experiments in terms of the kinetic features and depositional characteristics of rockslides, including crack propagation, velocity distribution, preservation of source stratigraphy, progressive fragmentation, and spreading of fragments. Conversely, the normalized horizontal runout and degree of fragmentation are poorly represented in the DEM model. A theoretical analysis is further conducted to discuss the causes of travel distance discrepancy between the DEM model and experiments. It is found that the inconsistency of fragment interactions caused by the defect of the fragmentation process in DEM simulation may take primary responsibility. An alterable restitution coefficient method based on the rock mass fragmentation process is proposed for application to the fragmenting rock mass movement in DEM simulation, with the utilization of additional laboratory experimentation as the calibration benchmark. Further verification of our method needs to be performed in the future.

中文翻译：

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滑坡中节理岩体的破碎和传播模拟：DEM 建模和物理实验验证

滑坡是最危险的地质灾害之一。离散元法（DEM）越来越多地用于模拟滑坡的就位过程。然而，很少有研究通过 DEM 模拟对运动过程中节理岩体的破碎进行建模，并通过与实验室实验和现场事件的结果进行比较来验证结果的可靠性。在本文中，基于 PFC3D5.0 进行了一系列 DEM 模拟，以复制实验室实验，其中具有不同结构形式的易碎块在水平面上撞击和滑动并经历破碎。结果表明，DEM模型在滑坡动力学特征和沉积特征方面提供了与实验结果相当的一阶估计，包括裂纹扩展、速度分布、源地层保存、渐进破碎和碎片扩散。相反，归一化的水平跳动和破碎程度在 DEM 模型中表现不佳。进一步进行理论分析以讨论 DEM 模型与实验之间旅行距离差异的原因。研究发现，DEM模拟中碎片过程的缺陷导致碎片相互作用的不一致可能是主要责任。提出了一种基于岩体破碎过程的可变恢复系数方法，用于DEM模拟中的破碎岩体运动，并利用额外的实验室实验作为校准基准。