Basic Research Of Leave And Design Theory Of Adjacent And Isolated Workface Waterproof Coal Pillar

The reasonable leaving of waterproof isolation coal-pillar is the key technology of preventing and solving the water-inrushing in goaf, which is relevant to many factors closely, such as coal seams’ occurrence environment, coal and upper rock seams’ physical-mechanical properties and distribution of workface. In this thesis, The problem of reasonable leaving of waterproof isolation coal-pillar was deeply and systemically studied through experimental research, theoretical model and field validity.According to stress redistribution theory and limit equilibrium theory, and coal mass’ s fractural state was considered, the structure of the waterproof coal pillar was divided into three parts, namely limit equilibrium zone, elastic zone and water-pressure fractured zone, as a result, a framework, that can analysis and determine the waterproof isolated coal pillar width furtherly, was built; With limit equilibrium theory and parabolic-style strength criterion and method of separation variables, the limit equilibrium zone width was determined; considering ground pressure and water pressure, adopted the UST, and then the elastic zone width was determined through the semi-inverse method; considering infiltrating softening effect, the water-pressure fractured zone width was determined; Through the mechanical modeling, the relationship between waterproof isolated coal pillar width and the geological factors, such as gob width, coal seam depth, ground stress, water pressure, and structure-strength factors, such as coal pillar height, compressive strength, infiltrating softening effect, deformation ability of pore structure, was analysis quantitatively; In order to apply to practical engineering conveniently, the program of leaving waterproof isolated coal pillar was wrote, and the selection principle and calculation method was discussed, which was meaningful to the guide of field work; To obtain mechanical model parameters of waterproof isolated coal pillar, the point load test for compressive strength, hydraulic fracturing test for ground stress were applied, which laid a fundamental for analysis of modeling parameters and engineering practice; The research result of the thesis was applied to the leaving work of waterproof isolated coal pillar in Dong Jia-he mine, found that: calculation result 2.83 m was close to the detective result by ultrasonic nondestructive equipment; surface waterproof isolated coal pillar width 30 m was same than that of pre-leaving in mine.Above all, waterproof isolated coal pillar leave and design system was initially built, which provided referential research method, laid a good foundation in further to enrich and deepen the study of such problems.