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Study On Water-inrush From Floor Under Confined Water And Technique Of Prevention And Control

Posted on:2016-01-29Degree:MasterType:Thesis
Country:ChinaCandidate:Y M WangFull Text:PDF
GTID:2191330479985581Subject:Engineering Mechanics
Abstract/Summary:PDF Full Text Request
Water inrush from coal floor is one of the main disasters in our country. Along with the mining of lower group coal in our country, the coal mines under the threat from confined water become more and more serious. After coal seam mining, the floor rock mass will be instability and failure under the combination of mining stress and water pressure, especially for floor with fracture. The water inrush from seam floor will happen. In this paper, the synthetically study means combined with theoretical analysis, numerical simulation and practical application is applied to study systematically the mechanics mechanism of water inrush from complete floor and floor with fracture. At the same time, the research is applied to evaluate risk of water inrush from seam floor in Longgu coal mine. Finally, measures of prevention and control of floor water are put forward. The study conclusions have been obtained:(1) Based on the elastic-plastic mechanics theory, the simply mechanics model of the distribution of force on the boundary of half plane body is established to analyze the additional stress distribution characteristics of the floor rock mass. The damage form of floor rock mass is obtained. It is found that the floor shear failure easily occurs in the coal wall. The expression of the maximum damage depth of coal floor is deduced.(2) Under the action of water pressure, for the complete floor, rectangular thin plate with clamped edges model is established to solve the ultimate water pressure value of floor bearing. The criterion of water inrush from complete floor is given. For the floor with fracture, water stress crack principle is used to analyze the rock fracture extension, penetration and water channel formation process. It reveals the mechanics mechanism of water inrush from floor with fracture under the influence of confined water.(3) The universal analysis software FLAC3 D is used to simulate the mining process. The distribution features of stress, deformation and plastic damage area of the surrounding rock in complete floor are gained. And confined water rise and seepage flow law are analyzed. For the floor with fracture, the macroscopic effect of water pressure on the fracture is simulated on the basis of improving the FLAC3 D program. The law of fracture extending and running through each other, then forming the passageway of water-transmit is obtained. The pore pressure rising height and seepage velocity are larger in fracture. Meanwhile, the influences of water pressure and dip angle of fracture on the water inrush from seam floor are analyzed.(4) The research results are used to evaluate risk of water inrush from seam floor in Longgu coal mine successfully. According to the coal mine actual situation, the technology of floor grouting is selected to prevent and control water inrush. Grouting increases the thickness of water-resisting floor. The fractures are filled and compacted. So safety mining of coal seam is realized.
Keywords/Search Tags:confined water, failure characteristics of mining, fracture, numerical simulation, prevention of water inrush from floor
PDF Full Text Request
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