Numerical Simulation Research On Ground Subsidence Of Thin And Mid-thick Seams Extracting

Linsheng mine in shenyang mining area is a typical one with declined thin and mid-thick seams in Liaoning province,which started producing coal in 1981 and was extracted for 30 years in sum from then on.The status of stress balance of the rock around mining area began to change after large quantities of coal in underground was extracted.Deformation ,movement and damage of the overburden of the extracted seams was caused from it inevitably and ground was affected finally ,subsidence or collapse took place on the ground.Because the deep coal seams underground was still being extracted, subsidence on ground and deformation level was enlarged by repeat mining,which made the ground unstable for a long time and prolonged the time of subsidence on the ground. Agriculture production and normal life of the people who lived in the surface of mining area was affected seriously by subsidence disaster which caused by it.So it is very important to study subsidence and ground movement behavior law of Linsheng coal mine and to predict ground range affected by subsidence after extraction of unextracted coal mines.Actually, a lot of declined seams existed in many mining areas all over my country.Angles of declined seams in nearly all mining areas are different as positions of a seam change. Subsidence of multi-angles declined seams extracting and ground deformation problem almost exist in most of declined coal seams mines.It has an important indierction effect to make an in-depth study about ground subsidence law of mines with such kind of seam espatially ones with such kind of seams and to prevent subsidence disaster.Linsheng coal mine is the most representative one in Shenyang mining area that was chosed to be the object of study in this peper.2-D finite elements model of Linsheng coal mine was founded ,in which the upper beams′angles were 28°and the lower were 45°.Large-scale finit element analysis software ANSYS 10.0 was used to study stress variation law of overburden and ground which was caused by extraction of multi-angles declined thin and mid-thick seams in different levels in condition of different extracting depth and strike long wall extracting all coals in one time .Simulation extraction of 5# and 12# coal seams which will be extracted in the lower mining orea are done according to numerical simulation analysis results at the same time.Possible affection range of ground will be predicted after these two seams will be extracted.Profile models were founded by the same analysis meathod along the striking direction of seam in west-two district, west-three district and west-four district of Linsheng coal mine to simulate and calculate the surface affecting region of the final extracting of seams in every profile model.Then the boundary point of surface subsidence and horizontal moving in every model was demarcated in surface plane projection graph of the mine field and surrounding field accourding to the real space location and connected by polyline in order,probable region in surface affected by subsidence was fixed.Certain basis is provided for preventation and cure of ground subsidence disaster in Linsheng coal mine and some referance values is important for study and prediction of ground subsidence of coal mines which own the similar geology extraction condition in other mining areas all over my country.