Index of multiple factors and expected height of fully mechanized water flowing fractured zone

On the premise of analysis on the development of water flowing fractured zone height by influence of various factors,a new parameter index namely hard-rock lithology ratio was proposed,which insteads of roof strata combination uniaxial compressive strength,avoids determination of statistical problem of uniaxial compressive strength by the type of hard and medium hard,weak,extremely weak roof in the current specification,and doesn't reflect the hard and soft strata combination roof structure.Based on the measured data of fully mechanized water flowing fractured zone of 39 cases,using multiple regression analysis,many factors of non-linear statistic formulas were obtained among height of fully mechanized water flowing fractured zone and mining coal thickness,hard-rock lithology ratio,working face length,mining depth,mining face advance and used for the expected height of water flowing fractured zone in Huainan Xieqiao first face mining.