Research On Mining Landslide Risk In Guanwen Coal Mine

Guxu Mine locates in transitional zone between the Southwestern mountainous area and the Yunnan-Guizhou plateau, with fluctuant mountains and vertical-horizontal ravines, where the surface erosion is fairly deep; the slope loose masses accumulates thickly, whose structure is unstable and loose; the bed rock is exposed outside and gets weathering with fracture developing seriously; the precipitation is abundant and the rainy season concentrates, thus the single precipitation is large. As the continuous mining underground, the geological disaster involving landslide, debris flow and collapse happens frequently. Consequently, it's essential to study the main impact factor of mining collapse in this area and to establish reasonable danger-forecasting system, which is significant and valuable to prevention of geological disaster.The research in this paper is in terms of the special geological mining conditions of Guanwen coal mine, locating in Guxu coal field(coalfield) in Sichuan province, it is also based on the investigation and a series analysis including landform, strata lithology, geological structure, mining conditions and present research on mining landslide(the present mining landslide situation), then it finds out that the main impact factors involves the landform, loose masses, underground miningand precipitation.The numerical simulation calculation is used to research on the mining landslide, whose results show that: the overlying strata move towards the center of the subsidence basin(gob) because of the underground mining, and there is horizontal movement towards the slope bottom at the slope top, which results in tensile and extrusion deformation and failure. With the increase of mining area, the disturbance range and the loose movement deformation of slope increase also, with extensive plastic failure. This failure increases obviously with little change on slope movement and deformation under repeated mining. The main influencing factors of mining landslide under the geological mining conditions of Guanwen coal mine are accordingly determined to be slope, loose accumulation physical properties, mining area, slope deformation and overburden lithology, and are classified into three categories i.e. geological, mining and environmental. The risk assessment model is established, in which the weight value of each influence factor is obtained by AHP method according to the relative importance among each other. The mining landslide risk D of Guanwen coal mine is calculated by the model to be 3.2, thus it is determined that the mining landslide is dangerous.Based on the analysis of the relationship between the open cut position of panel 11905 and 11103 and buildings to be protected, two mining schedules adopting different horizontal distance between the cutting hole and the mountain top are put forward, i.e., 194 m and 122 m for panel 11905, 130 m and 70 m for panel 11103, and following by the model analysis. The result indicates that when the horizontal distance is 130 m and 70 m respectively, the danger level D is 2.8 and the landslide is less likely to happen. The analog simulation is carried out to prove the rationality of the above evaluation, and the safety and reliability of the mining schedule are determined.