Characteristic analysis and kinematics simulation of slope collapse in coal mine industrial site excavation

Coal mining activities in northern Shaanxi are frequent and continuous, which is easy to cause a series of geological disasters. The excavation slope caused during the construction of the coal mine industry site is likely to cause hidden dangers of collapse, which poses a great threat to the buildings, equipment, personnel and vehicles on site. At present, the two-dimensional analysis method based on slope surface profile is often used for the analysis and prediction of collapse hazards. There are many disadvantages such as the randomness of artificially selected collapse movement path and the inability to study the distribution range of collapses in the third dimension, making it difficult to efficiently evaluate collapse disasters. In order to solve these problems, this article takes the excavation slope of a coal mine industrial site in northern Shaanxi as an example. Based on the field survey, the UAV automatic aerial photogrammetry and automatic establishment of high-precision three-dimensional ground model technology, point cloud data extraction of structural plane parameters and three-dimensional collapse movement simulation technology were used to analyze the statistical characteristics of historical collapse distribution, occurrence of rock mass structural plane and dangerous rock mass in the source area, and the movement characteristics of the excavated slope collapsed dangerous rock mass were simulated. Through simulation, the trajectory, impact range, bounce height and energy distribution under the optimal path of the collapse were obtained. The results show that the dangerous rock area mainly threatens the living area on the northeast side of the industrial site and the parking lot on the southeast, and will not pose a threat to the G338 National Highway in the middle of the industrial site, the loess shoulder and the river water surface on the west side of the industrial site. Among them, the area A has the largest impact on the living area, which is 62 m, and the area D has the largest impact on the parking lot, which is 105 m. In the optimal path, the distance between the center of mass of rockfall in dangerous rock area D and the slope surface is the largest, 8.33 m; the rockfall mass center of the area A has the largest height from the living area, which is 4.59 m, the distance between the center of mass of rockfall in dangerous rock area C and the parking lot is the largest, 5.85 m. The passive protective nets can effectively prevent rockfalls from the area A, and have no significant protective effect on rockfalls from the area B, and have no protective effect on dangerous rock areas C, D, E, and F. The relevant research conclusions can provide certain guidance for the disaster management and prevention design of collapse.