Discrete element modelling on dynamic triggering mechanism of the Pusa landslide in Nayong county, Guizhou Province

This paper presents a discrete element modeling using UDEC software to reproduce the dynamic response of the Pusa landslide triggered by the combination of goafs, deep major karst cracks, heavy rainfall and continual blasts during underground coal mining. Based on the reproduction, the dynamic triggering mechanism and the key contributing factors of the landslide are analyzed. The results show that caving, crack and deformation zones that developed in the strata overlying goafs during mining coal seams expand up gradually below the slope. The deformation zone meets the toe of the original slope after mining of the uppermost coal seam. Meanwhile, an obvious progressive deformation zone develops in the original slope containing the deep karst fractures. The deformation behaves as a wholly downward and clockwise movement. On the condition of the heavy rainfall, a continuous progressive deformation zone develops in the slope that has been influenced by the goafs. The deformation continues to behave more downward and clockwise movement as a whole. Finally, while the continual stope blasts, as the key contributing factor for the landslide, during the underground coal mining, the slope that has been influenced by the goafs and the heavy rainfall enters multiple-phase dynamic response stages including further progressive damage deformation, critical collapse, shattering, ejecting and compaction. Simultaneously, the whole slope exhibits a downward, apart break and clockwise rotation. These results modeling would provide a support for control of similar landslides.