| The Gaojiapu Coal Mine is located in the northwest of the Binchang mining area of the Huanglong Jurassic coalfield.It has the characteristics of large buried depth,high water pressure and high stress.During mining,the water inflow is extremely huge,and the problem of rockburst is prominent.In order to explore the relationship between groundwater flow field and rockburst,and exploit coal resources more scientifically and safely,it is necessary to deeply study the flow field evolution characteristics of extremely thick and strong water rich aquifer and its influence on in-situ stress field.This thesis takes the first mining area of Gaojiapu Coal Mine as the research object.Based on the analysis of hydrogeological data,aiming at the Luohe formation aquifer threatening coal mine safety production,this thesis studies the evolution of groundwater flow field in Luohe formation aquifer during mining in working face 101,and reveals the temporal and spatial law of large flow inflow flow field evolution caused by mining.Based on the hydrogeological and engineering geological characteristics of the Luohe Formation,the boundary conditions and model horizon are generalized,and the initial water level of the model is assigned and adjusted according to the results of hydrological observation well data and rock physical property test.A three-dimensional groundwater model in the first mining area of Gaojiapu Coal Mine is constructed and identified and verified.The results show that the simulated value is consistent with the measured value.Using the methods of theoretical analysis and numerical simulation,the effects of elastic water release,dynamic water pressure and stress concentration on the in-situ stress field were revealed under the condition of large flow and hydrophobicity.Drawdown and elastic release of water are linearly positively related to the stress increment of the rock mass at the bottom of the Luohe Formation per unit volume,and the stress increment is between 0.01008 MPa and 0.0126 MPa when the water level drops by 1m.The water level drawdown is exponentially related to the stress increment caused by the dynamic water pressure,and its influence is too small to be ignored.The stress concentration of coal seam roof caused by large flow hydrophobic is mainly manifested in the center area of water level depression funnel caused by hydrophobic,pressure relief area appears on both roof of Luohe Group and coal seam roof,vertical stress decreases,pressure boosting area appears on the edge area of depression funnel and vertical stress increases.This thesis analyses the mechanism of large flow hydrophobic in the first mining area of Gaojiapu Coal Mine which induces rock burst in the roadway,which is caused by high static overlapping dynamic load.According to the mining plan of the mine,the flow field from 2021 to 2022 is simulated in two stages.By predicting the effect of dynamic evolution of flow field on stress field in the first stage,the area prone to impact accidents is pointed out and compared with the area where the actual roof fall accident occurs in this period,which verifies the feasibility of this theory.It has certain guiding significance for safe mining.Predict the evolution of flow field in the second stage and its influence on in-situ stress field,analyze the stress concentration area of coal seam roof and give some suggestions.There are 83 figures,8 tables and 97 references in this thesis. |
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