Development Height And Rich Change Of Water Fissure Zone In Daluta Mine Law Research

The influence of underground high strength mining on the occurrence condition of underground aquifer is very serious.In this paper,theoretical analysis,numerical simulation and field measurement methods are used to analyze the variation law of water abundance of underground aquifer under the mining of 52305 working face and adjacent face in Daliuta Coal Mine.By means of high density resistivity method and ground penetrating radar,three-dimensional reconstruction of electrical data and dynamic inversion of shallow formation moisture content,the variation haracteristics of water abundance of coal and rock strata before,during and after coal mining are observed,and the evolution law of water abundance of various strata during coal mining is studied.The main research results are as follows:(1)Application of thcoretical analysis combined with drilling detection results,through the 1-2,2-2 and 5-2 three-layer coal down sequence mining prediction,the development height of upward water flowing fractured zone did not break through the main key layer,the main key layer and its overlying strata did not break,the development depth of downward water flowing fractured zone was 25.78 m,and the development of water flowing fractured zone partially penetrated the surface;through numerical simulation,it can be seen that the development height of water flowing fractured zone after 5-2 coal mining is 135 m,and the fracture-production ratio is 19.The numerical simulation is consistent with the theoretical calculation results.(2)Through the detection of high density resistivity method,the dynamic water-rich change law of coal aquifer is revealed,and the fitting results reflect the development law of water flowing fractured zone to a certain extent.The surface water abundance decreased first and then returned to the pre-mining state under the influence of mining;the underground aquifer(Salawusu Formation aquifer)is affected by mining,showing local groundwater leakage loss,water-rich decline,reaching pre-mining level after mining stability;the main key layer is affected by mining,water-rich in the layer is infiltrated,water-rich becomes low,and water-rich does not recover after mining.The coal seam is basically dry without water content before mining.During the mining process,the resistivity decreases slightly locally,and the water-rich property is not strong.After the mining effect,there is a local water content or weak water content distribution.The variation degree and loss path of water-rich property affected by mining are consistent with the numerical simulation results of fracture propagation in plastic zone.(3)The water content of clay layer affected by evaporation can be divided into A and B zones from top to bottom.At the beginning of mining,the water content of A zone increases with the increase of depth,and the water content of B zone decreases with the increase of depth.Surface deformation cracks caused by mining will evaporate with the cracks,resulting in the depth of A zone increased.By comparing the thickness changes of zone A in the same affected area under different detection times and in different affected areas under the same detection time,it is found that the maximum thickness of zone A in the tensile affected area at the same time corresponds to the lowest moisture content and the most serious damage.Under the same influence area,the thickness of zone A under mining is the thickest,and the difference of water content-depth curve obtained by each detection time is the largest,indicating that it is most affected by mining.This is consistent with the reality,so it is feasible to judge the severity of surface damage by the change of water content in zone A.The mining area studied in the thesis provides a reference experience for other mining face of the same type.