Study On The Coordination Control Of Gob-side Entry Retaining In Near Shallow Seam With Fully Mechanized Caving Method

The coal resource is very rich in western china, to implement the Gob side entry retaining technology in the western region with downward economic situation has many advantages, improving the coal recovery ratio, decreasing roadway drivage ratio, loosing mining replacement tension, and it is of great significance to realize the sustainable development of coal resources in Western china.By comprehensive using of field investigation, theoretical analysis,numerical simulation, similar material simulation, and the method of field monitoring, this dissertation began with the study of overlying strata movement law for gob-side entry retaining in near shallow seam,established the mechanic model of the compatible deformation of surrounding rock for gob-side entry, analyzed the deformation compatibility relation between the bearing structures, and revealed coordinated control mechanism of surrounding rock for gob-side entry retaining t under the condition of main roof of confined deformation.Main results are as follows:(1)The physical and mechanical parameters of the strata of 4# coal seam roof are obtained through the indoor mechanics test, such as uniaxial compressive strength, elastic modulus, Poisson's ratio, cohesion,friction angle, etc. The results show that the seam roof mainly consist of sandstone and mudstone, of which the rock strength is poor, and the rock mechanics parameters obtained from indoor test can provide the basis for numerical simulation and similar material simulation test.(2) Under the research of overlying strata movement law for gob-side entry retaining in near shallow seam by field monitoring,similar material simulation test and theoretical analysis, the structural characteristics and key block parameters of lateral roof are analyzed.And the stability of surrounding rock influenced by the coal sides and backfilling body is also studied systematically.(3) The mechanic model of the compatible deformation of surrounding rock for gob-side entry is established under the condition of main roof of confined deformation, based on the analysis of the deformation compatibility relation between the bearing structures, such as coal sides, backfilling body and gob caving gangue, the maximum rotation angle of rock beam can be confined ,which can be regard as a criterion to maintain the stability of gob side entry retaining wall. That is to say, the rotation angle of the roof rock beam 0 should meet??min{?Mmax,0Fmax,?Wmax}.According to the principle of deformation compatibility, the paper puts forward the quantitative control measures for the deformation of surrounding rock.(4) Analyzed the overlying strata movement law and surrounding rock deformation of gob side entry retaining by using the method of UDEC numerical simulation, and the influence of bearing structure (coal sides and backfill body) on stability of surrounding rock of the gob-side entry retaining have also been studied. the simulation results show that the coal sides, backfilling body, as the combined bearing structure to maintain the stability of the surrounding rock, any failure will lead to failure.The research results are applied successfully in 41102 fully mechanized mining face of Awuzisu coal mine. Results show that the existing roadway support scheme, backfill parameters can fairly well solve the surrounding rock deformation, which provides the reference for the similar conditions of coal mine.