Abstract
Purpose. To assess the storage capacity of the mined out and flooded section of the mine field for hydrogeomechanical risk determination, prevention of water inflow emergencies and substantiation the engineering protection measures in influence zone of the water body. The methods. Predictive calculations were performed using the methods of numerical mathematical modeling of hydrodynamic and geomechanical processes implemented by the method of finite differences and finite elements. Simulation technique involves the solution of a series of inverse problems, which allows us to obtain high reliability forecasts in conditions of multi-factorial influence and uncertainty of the rock massif state. Findings. The sandstones of the main roof of the coal seam have a dominant influence on the water influx formation into designed workings within the influence zone of flooded section of the mine field. Flooded mine workings due to increased hydraulic permeability play the role of a recharge contour, which appears as keeping the hydraulic pressures over the designed galleries. Involvement of the designed workings into post-ultimate deformation zone occurs when their distance from the flooded contour is less than 20.0 m, going beyond the zone of shear deformations – when moving away to a distance of 30.0 m. According to the hydrogeomechanical condition of the rock massif, the calculation option, where the designed workings are placed at a distance of 20 m from the flooding contour, is the most optimal. Since the geotechnical situation is determined by a significant number of probable characteristics (properties of rocks, water influx rates, the boundary and timing of flooding, the mapping accuracy of the geological structure of the site), as well as the substantive influence of rock structural and textural characteristics around flooded workings, technological measures of mining under protection of hydrodynamic depression have been developed. The originality. The regularities of the water balance formation within the area affected by the flooded workings, and the dependence of the geomechanical parameters of massif stability on the state of the excavated space, pressure values, and the barrier pillar dimensions were found. Practical implementation. Parameters of barrier pillar, which allow minimize hydrogeomechanical risks and mineral deposit loss are substantiated. Recommendations concerning mining operation procedure around flooded workings under protection of hydrodynamic depression are given.
Published Version
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