Study on overlying strata caving and movement regularity of ascending mining in contiguous seams

In order to study the overlying strata caving and movement regularity of ascending mining in contiguous seams,according to the specific engineering geologic conditions of contiguous seam group for a mine in Jincheng city,a two-dimensional physical simulation model was built. The overlying strata caving and movement were monitored during the excavation of coal seam group.The results showed that during the full process of the ascending mining,the upper coal seam has shorter periodic weighting length and larger height of bed separation than the lower coal seam;the upper coal seam had large and short periodic weighting length,and showed the phenomenon of serious and mild periodic weighting respectively,the face caving angle decreased during the small periodic weighting period and increased during the large periodic weighting period;after the excavation of the upper coal seam,the overlying strata was hard to form stable structure and the increase rate of the bed separation was small. The results could provide the reference for the ascending mining and ground control in the similar coal seam.