Study On Rock Pressure Of Donghai Coal Mine Deep Coal-seam Working Face

The engineering examples of Donghai mine 32# seam left 9 working face, adopt the method combined theoretical analysis, field observation, laboratory testing and numerical simulation, through theoretical analysis and practical investigations on the rules of roof strata activities, behavior of superincumbent strata and the distribution of abutment pressure of 32# seam left 9 working face, obtain various parameters of roof activity on this working face, range of behavior of superincumbent strata and characteristics of abutment pressure distributions, provide reference for surrounding rock control in coal face when the same coal mine of LongMay MINING GROUP CO.LTD goes deeper mining.Through analysis the observation data, obtain that first weighting interval of main roof is 45.8m and the average periodic weighting length is 19.7m; through similar material simulation test, obtain that roof in goaf form caving zone, fractured zone and bending zone.The height of the caving zone is about 5.2m, is about 3.8 times mining height; the height of fractured zone is about 30m, is about 22.1 times mining height; the height of bending zone is153.4m. Subsidence coefficent of different depths strata vs. ratio between strata height to the roof and thickness of coal seam mined have linear relationship, subsidence coefficent of strata decreases with the height of strata increased. The maximum value of abutment pressure changes with working face advance, the range of anallobar can reach about 100metres.RFPA is used to analyze the rules of roof strata activities and distribution of abutment pressure,the results of field observation and similar simulation are contrasted with the analysis rules using RFPA. Through analysis on comparing with some data of shallow mining, there is no direct relationship between presentation of the mine pressure and mining depth. With mining depth increased, abutment pressure slightly increase, the ratio of caving zone and fractured zone vs thickness of coal seam mined is higher than data of shallow mining. The relationship of the distribution of abutment pressure and the height of the caving zone and fractured zone vs mining depth remains to be further investigated.