The Basic Study On Strip-filling In Goaf

The mining method of strip-filling is an important part in the "under three" mining technology, using cementing coal gangue to fill goaf.And also, it have milestone meanings for eliminating the waste dump of the ground, improving the mining rate of coal and keeping the coordinated development between economy and environment. Combing with the geological conditions of Caocun mine Huozhou of Shanxi coking coal group, this thesis uses laboratory experiments, theoretical analysis, numerical simulation and industrial test for further study.First of all, cement, fly ash and gangue are choosed as raw materials. Using orthogonal experiment, we conduct a study on proportion design. The results show that when the mass ratio of cement to fly ash to gangue is1:5:16and the slurry density is75%～80%, the early and later strength are both increased. But also, it is suitable for pipe line transportation.The deformation mechanism, parameter layout and stability of strip-filling and roof are important in the design principles of strip-filling. On the basis of the previous researches, according to the combination beam theory, we confirm the load on the immediate roof. According to the simply supported and clamped beam theory, the mathematical expression of the distance between strip filling body is obtained. According to the theory of plates and shells and Winkler’s elastic foundation beam, the mechanical model of strip filling body-immediate roof-overlying strata is assured. We obtain the mathematical expression of the max deflection of the immediate roof. According to the theory of the A.H. Wilsion’s two-constrained-erea and King’s effective-erea, We obtain the mathematical expression of the width of the filling body.With the application of FLAC3D, combing with the geological conditions, the thesis analyzes the width of plastic area, stability of filling body, and roof activity and its stability on the condition of different width, cohesion, and internal fricition angle for the filling body. The study shows that the safety factor is1.29when filling body’s distance is15m, filling body’s width is30m, internal fricition angle is28°～31°, and cohesion is0.9MPa～1.2MPa. At the same time, the immediate roof displacement is only0.051m, less than the maximum perturbation0.092m after face advance225m, filled with5strips. The results reflect that the filling body can control the immediate roof’s displacement and can maintain the roof integrity well.Use of the results of the previous researches, it is tested in coal mine. The three quantities are observed during the45d in the working face. It shows that strata behaviors are not significant. Therefore, using this method can take considerable economic benefit and social benefit.