Mined Rock Damage Numerical Simulation Of Water Body

After ore body is mined, the damage height of superincumbent stratum of the goaf has an important effect on stability of the surrounding rock and the safety in the subsequent production. Especially , when mining ore body under large-scale water body, ascertainment of the damage height of superincumbent stratum and its distribution is very important for solving the contradictions between mineral resources exploitation and utilization under water body and mine safety, fully utilizing the mineral resources of mine, prolonging the service life of mine, improving the economic efficiency of enterprises.Affected by the heterogeneity and anisotropy of rock mass, the occurrence conditions of ore body, mining method, the height of the mining, the roof management method and other factors, the dynamic development process of the overburden failure above the gob exhibits the complex time and space effects. This paper chooses a certain metal mine under the canyon waterbody in Yun-Nan as the objects. Through the field investigation, the type of the hydrological geological and the mine source of water gushing are judged, and the effect of the structural plane of the fault, joint and bedding on the stability of rock is analyzed. The mechanics parameters of rock mass have been obtained by laboratory tests, field investigation and engineering analogy method. And according to mining design, FEA model is established, the damage rule of superincumbent stratum of the goaf is simulated with increase of mining depth. Finally, the following conclusions have been made.1. Before excavation of ore body, it can be occur to stress concentrate phenomena in the canyon bottom. In the direction of 3rd principal stress, the compressive stress is the main stress. The 3rd principal stress parallel to slope surface nearby slope, and it parallel nearly horizontal direction under the canyon bottom. In the direction of 1st principal stress, the compressive stress value is very low, even it becomes tension stress. The 1 st principal stress is nearly perpendicular to slope surface nearby slope.2. During ore body excavation, the most effect on the surrounding rock stability of the gob is the tension stress in the hanging wall rock and footwall and the stress concentration at the lower and upper corner of the stope.3. When the ore body at level between 1,367m and 1,282m is mined, the plastic zone of the superincumbent stratum rock of the goaf is not connected with the plastic zone of the ground surface, and the distance between them is about 34.5m. Accordingly, in this case, it can be thought that the water flowing fracture zone does not link up with surface water body, the probability of the water permeable accident occurrence is small.4. When the mine exploitation up to 1,165m elevation, the distance is about 25m between plastic zone of the superincumbent stratum rock of the goaf and plastic zone of the ground surface. The water flowing fracture zone does not link up with surface water body yet. Accordingly, it can be thought that when mining ore body at the level of 1,165m, the probability of the accident of large-scale sudden flooding is very small. But the thickness of no-damaged zone will further decrease, the water quantity that Surface water seepage into goaf may increase.