Gob-side Entry Retaining In Large Inclined And Medium Thick Coal Seam With Weak Roof And Floor

No coal pillar mining, which is studied and applied vigorously at home and abroad,is a new technology that attached with these advantages as improving the coal recoveryratio, decreasing roadway drivage ratio, cutting down the per ton coal cost, prolongingmine service-life, loosing mining replacement tension and preventing undergroundaccidents caused by the reason of protecting coal pillar and losing coal. The successfulresearch and application of this technology will bring significant social and economicbenefits. On the other hand, the technology of gob-side entry retaining has not beenwidely popularized and applied at home and abroad, only in the situation where theorebody is nearly horizontal and gently dipping medium thick as well as the roof andfloor condition is appropriate, the technology of no coal pillar mining is studied andapplied well. While another research in the situation of large and deep inclination andother complicated geological conditions is still not mature. So the research of projecthas the important theoretical significance and application value.In this paper, with Sichuan coal group Tieshannan-1113Working Face as theengineering background, using the methods of combining theoretical analysis,numerical calculation analysis, and field test, the supporting scheme of gob-side entryretaining in combine machinery mining face with large inclination and medium thickcoal seam was compared, the rational and effective supporting scheme of gob-side entryretaining was obtained. There main search achievements are as follows:(1) By analyzing surrounding rock activities of large inclination coal seam miningand the equilibrium structure of roof bond-beam structure, the mechanics model ofgob-side entry retaining in coal seam with large tilt angle was established so as toprovide the scientific basis for supporting design of gob-side entry retaining;(2) Through the study on the movement regularity of surrounding rocks andcommon supporting methods of roadside support and roadway support, the supportscheme of the cable(bolting) anchor with joist steel is used in roadway support, and fiveroadside supporting schemes were designed based on actual conditions, that is:1):supporting of concrete pouring,2): supporting of gangue and concrete pouring,3):supporting of pillar of discarded rails in single and dense row0.5m near the roadsidewhile blasting roof cutting in1m near the roof of roadside in normal direction.4):normal blasting roof cutting in0.5m near the roof of roadside in80°direction.5): supporting of pillar of discarded rails in single and dense row1m near the roadside.(3) Numerical simulation analysis is respectively carried out for the each schemeusing the numerical analysis software UDEC, the deformation of surrounding rock ofthe five supporting scheme is obtained, and the best one is determined.(4) By engineering practice and strata control observation, draw a conclusion that,it is reasonable that using combined support scheme of the cable(bolting) anchor withjoist steel in roadway support and support scheme of natural falling and filling withgangue in roadside support. After above all, gob-side entry retaining is completed.