Study on mine strata behavior law of fully-mechanized top coal caving mining in contiguous coal seams

In order to deeply study the mine strata behavior law of the fully- mechanized top coal caving mining in the contiguous coal seams,based on No.SIN_26-7 coal mining face in Liugjia Mine as the study object,the numercal simulation and sie actual measuring method were appied to analyze the roof movement law,the surrounding rock stress law and the working resistance of the powered supports applied in the coal mining face. The UDEC numerical simulation results showed that under the infuence of the cal mining in the top No.6-6 seam,the initial of weightng span and the periodical roof weighting span of No.STN_26-7 cal mining face were all reduced,the stress peak was reduced from 24.1 MPato 17.0 MPa and the infuence scope was increased from 40 m to 120 m. With the monitoring and measuring on the working resistance of the powered supports applied in the coal mining face,under the role of the top goaf the initial support force of the powered supports applied in the coal mining face was low. The initial roof weighting span of the coal mining face was 29.9 m in average,the periodical roof weighting span was 13.6 m inaverage and the dynamic loading c efficient was 1.13 during the periodical roof weighting. The study showed that under the role of the top goaf:he advanced support pressure of the coal mining face and the roof weighting span were all reduced and the intensity of the mine strata behaviorwas reduced.