The Movement And Deformation Research About Overburden Surface Filled By Coal Gangue

Coal is the main energy in China, with China’s rapid economic development, energy demand a substantial increase in coal mining, that make the increasing scale. Resources which are easy to mine reduce day by day. At the same time, three under (buildings, railways, water) stagnant coal and unreasonable exploitation, it has become an important problem restricting the development of mining area stability sustainable exploitation and mining production. Traditional roof caving mining will cause surface subsidence, resulting in land resources, roads, bridges, pipelines and other damage. In addition, treatment of downhole gangue tradition is by the downhole to surface accumulation, not only occupy a lot of land resources, environmental pollution, but also there is coal gangue spontaneous combustion, which is a direct threat to human life and safety. Taking the gangue filling mining method, not only can reduce the discharge of solid waste in coal mine underground structure, and can be used as a support body, reduce the mining subsidence disaster, improve the recycling rate of the mine resource, protect the ecological environment of mining area, liberal the coal resources that are under village buildings, railways, water bodies.Taking FenXi mining (group) XinYang coal mine10203working face as the demonstration of fully mechanized working face, research the new filling material and filling fully mechanized process filled with coal gangue and use FLAC-3D numerical simulation methods to analysis the roof vertical stress level and coal wall stress variation and the changing law of overburden rock displacement in different working face length, the different filling rate and the filling body strength. Through the Optimization simulation we obtained the relationship between the mining thickness, maximum displacement and the different height of overburden rock. Finally use the subsidence prediction software to predict the surface movement deformation and to validate the correctness and practical operability about the formula. The conclusions as follows.(1) Under a certain filling rate and strength of filling body, coal wall horizontal stress increases gradually with the increase of mining face length, vertical stress of the roof decreases with the increase of mining working face length. Under a certain mining face length and strength of filling body, horizontal stress of coal wall and vertical stress of the roof increases with the increase of filling rate gradually, And under a certain mining face length and filling rate, two stress increases gradually with the increase of the strength of filling body.(2) The farther distance of overlying strata is, the smaller its the maximum vertical displacement will be. When the filling rate is small, the difference of its displacement is great. But the greater the filling rate is, the smaller the difference of its displacement and it will gradually level off. From the intensity of filling body, the greater the intensity of filling is, the smaller the overlying strata displacement will be. When filling intensity reaches a certain degree, the strata displacement can no longer continue to increase with the increase of filling intensity but remains in a stable value nearby.(3) Through analysis of the maximum vertical displacement of mined-out area center above strata within different height the point, the relations of the maximum vertical displacement, the height of the strata from the roof and mining thickness have been obtained. And the formula is suitable for calculate the maximum vertical displacement of strata within different location in the filling mining conditions.(4) The surface movement deformation under different filling rate has been expected and it has concluded that the extent of damage of structures from the surface movement caused by mining can control within I damage level in85%of filling rate.