Numercial Simulation Research on Surface Movement of Gangue Backfilling Mining under the City

摘要

The gangue backfilling mining technologyis an effective way to mine the coal resource under the city.The Tangshan coal mine is located in Tangshan city, Hebei Province, which has a history of more than one hundred years.Most of the remainder coal resource is under the buildings, and this situation is unfavorable for the development of the coal mine.By solving the "three-under" coal resource safely and efficiently,we can lengthen the service of coal mine,and it is good for having a harmonious development between economic and social in this area.There are many buildings on the Tiesan mining area, and Tangshan coal has used strip mining technology for mining some coal resource of 5 # and 8 #.Considering the strip mining has a lower production rate than others.The Tangshan coal will use the gangue backfilling mining technology for mining the 9 # coal resource with 4m coal thickness, and this way can control the surface movement and protect the buildings on it.According to the geological and mining conditions,we establish the 3D numerical simulation model for analyzing the mining subsidence,study the coal pillar stability of 5 # and 8 # coal seam under the condition of 9 # coal resource backfilling mining,and obtain the surface deformation.The results show that the coal pillar will not collapse if the fill level is under 85％.The ground has slowly movement, and the largest horizontal deformation is less than 2mm/m,it can protect the ground buildings well.