Journal of Engineering Research

With the increasing mining depth of open-pit coal operations, the stability of reverse-inclined layered rock slopes affected by faults has become an increasingly critical issue. Taking the Huolinguole Ancient City open-pit coal mine as the engineering background, this study investigates the landslide failure mechanism of high and steep reverse slopes influenced by the normal fault FD1 using the MatDEM discrete element numerical simulation method. A microscale slope model containing a normal fault was constructed and calibrated based on laboratory test data for mudstone, siltstone, and lignite to obtain the corresponding microscopic parameters. Dynamic evolution simulations under self-gravity were then conducted. The results show that under the combined influence of normal faults and reverse-inclined stratified structures, slope instability typically manifests as a bedding-shear composite sliding mode. The failure surface initiates along the weak plane of the hanging wall of the fault and propagates along the weak interface at the coal seam floor, forming an overall “large-head and small-tail” landslide morphology. This failure mechanism reveals how normal faults significantly weaken slope stability by disturbing the stress field and providing preferential slip pathways. The findings offer valuable theoretical guidance and practical reference for slope stability evaluation and disaster prevention in open-pit coal mines under complex geological conditions.

Open-pit coal mine; Fault; Anti-dip layered rock slope; Landslide; MatDEM