Analysis of Strata Behavior in the Process of Coal Mining by Gangue Backfilling

The gangue backfilling technology directly using gangue to replace coal buried under buildings,railways,and water bodies is very important in green mining.The mining methods with gangue backfilling in both the fully-mechanized coal mining(FMCM) and the conventionally mechanized coal mining(CMCM) are briefly introduced in this paper.According to a great number of tests on bulking and compaction properties of gangues,we proposed the conception of equivalent mining thickness in coal mining by gangue backfilling so that the traditional rock pressure theory and the prediction method for ground subsidence may be used to analyze the maximum values of strata behavior and ground subsidence.From theoretical analysis and the in-situ measurement,we have obtained that the coal mining by gangue backfilling may obviously decrease the severe degree of the strata behavior and ground subsidence compared with the coal mining without using the gangue backfilling under the same geological conditions.What is more,the gangue backfilling technology can be used to exploit those coal seams under buildings,railways,and water bodies which can not be mined out by using traditional mining method.