Analysis On The Strata-pressure Law Of Full-mechanized Caving Face And Sectional Coal Pillar Width Optimization In Dafosi Coal Mine

Research on the strata-pressure behavior law of full-mechanized caving face andoptimization design of sectional coal pillar width under complicated conditions has importantengineering value. This paper took40110full-mechanized caving face in Dafosi coal mine asbackground and studied with the methods of laboratory test, theoretical analysis and fieldobservation. The main conclusions follow:(1) It analyzed the main factors affecting strata-pressure behavior law of the fullymechanized caving face under complicated conditions. Through the establishment ofmechanics model of stope support and surrounding rock, it studied the relationship betweenthe main roof, immediate roof, stent and floor, and their role in the mining process, given thefully mechanized working face support pressure distribution characteristics and distributionrules of stent working resistance.(2) It completed the observation scheme design of strata-pressure behavior law ofDafosi mine40110fully mechanized caving face. The monitoring results show that, firstweighting length was61.70m, the periodic weighting length was16.37m, the dynamic loadcoefficient was1.57and the advanced effects range of working surface dynamic pressure was56.4m. Combining with the stability analysis of hydraulic support, it determined the stent hadgood applicability for40110fully mechanized caving face.(3) It analyzed major factors impacting of sectional coal pillar width setting of fullymechanized caving face, and given the main reasons of section coal pillar failure. Based onthe design principles of sectional coal pillar optimization, and combined with the actualsituation of Dafosi mine, the section coal pillar width calculation formula of fully mechanizedcaving face was put forward. (4) It studied sectional coal pillar setting width of Dafosi mine40110fully mechanizedcaving face with FLAC3D numerical simulation. The coal pillar width was50.6m throughFLAC calculation; the coal pillar width was51.83m through theoretical calculation.Considering the complexity of the stope, based on FLAC3D numerical simulation andtheoretical analysis results and considering safety factor, it suggested the coal pillar widthbetween Dafosi mine No.4coal face optimize from60m to52m, the distance betweengrouting roadway and two trough spacing was23.7m.