Study on roof weighting features of high cutting height fully-mechanized top coal caving mining face based on Comprehensive Analysis Method

In order to full accurately analyze a periodic roof weighting features of a high cutting height fully-mechanized top coal caving mining face,a'Comprehensive Analysis Method'of the periodic roof weighting was provided.By combination of a direct judgement method and a mathematical judgement method,an applied case analysis was conducted on the high cutting height fully-mechanized top coal caving mining face in Suancigou Mine.The results showed that the size of the roof weighting step distan ce,a sustained length of the roof weighting,average loading of the roof weighting,max loading of the roof weighting,dynamic loading coefficient would be 18.4 m,4.1 m,1566 6.5kN,17 712.8 k N and 2.24 in average.The load of front legs in powered support would be 2.46 times that of rear two legs in average. Thus the load variation of the two r ear legs would have important judgement role to the roof in periodic weighting status,such as a periodic roof weighting,small roof weighting and others.There would be two grades of roof weighting in high cutting height fully-mechanized top coal caving mining face,they were the periodic roof weighting and a local roof weighting or a small roof weighting.Periodic roof weighting could be divided into large step distance roof weighting and small step distanceroof weighting. The step distance size of the periodic roof weighting would have a certain positive related relationship with the roof weighting sustained length.