Goaf-water Inrush Models Of Hydrogeologic Structure And Its Disaster-mechanism In Shanxi Province

Taking goaf-water inrush accidents in Shanxi Province as research area,the paper satisfied the major accidents in 2000 ~ 2018 and summarizes its laws.The water disasters types of goaf-water are classified according to the difference of spatial location of water disasters,relationship of rock structures and mechanism of water disasters.In order to reveal the difference of various water disasters types,the paper studied them follow three levels,the hydrodynamic characteristics of goaf-water,the evolution of water inrush channels and the mechanism of water disasters.By constructing "the reservoir model",the relation between water pressure(P)and velocity(v)of the " separation type" of goaf-water disaster is deduced.In order to verify the correctness of the P~v relation curve,a goaf drain test was carried out and the actual P~V curve was obtained in a typical coal mine.In this paper,the analysis and comparison of the actual and theoretical P ~ v curves are made,and it is concluded that the actual P~v curves are consistent with the theoretical P~v curves in general,but there is a deviation to a certain extent.According to the actual shape of P ~ v curve,it is inferred and verified that there is a process of transition from "unsteady flow in pressurized pipeline" to "quasi-constant flow in pressurized pipeline" in the "separation type" goaf outburst flow state.In this paper,FLAC3 D numerical simulation method was used to simulate the channel evolution under the seepage condition of the "separation “types.The result display that the range of plastic failure zone under the condition of high-pressure water-bearing in goaf will obviously increase.The “separation of coal pillar” type's seepage failure is main in coal pillar,and the “separation of gate wall” type's seepage failure is main in its side rock and its bottom.Taking the typical of goaf-water inrush accident in Jiang Jiawan Coal Mine and Zhangcun Coal Mine as examples,the paper used method of theoretical analysis to explain its disaster-causing mechanism.It is considered that the reason for the water nrush accident in Jiang Jiawan is that the top plate collapse zone of No.8 coal and he failure zone of the bottom plate of No.7 coal are connected with the thickness of he waterproof layer between No.8 coal and No.7 coal,which leads to the inrush of water in the goaf of No.7 coal.It is considered that the reason of water inrush accident in Zhangcun Mine is that the water pressure of old empty air in the old goaf area of Yaobei Mine is rising after closing the well,and at the same time,the“separation coal pillar” is weakened by the goaf-water immersion,which results in insufficient water insulation capacity of coal pillar,and finally leads to the occurrence of water inrush accident.