Roof stability analysis model of super-long fully mechanized working face and its application

The strata behavior of a fully mechanized working face is obviously different from that of a short working face after the dip length of the coal face is lengthened. In view of the characteristics of high frequency, high peak value and large range of weighting in super-long working faces, a mechanical analysis model based on elastic foundation beam theory was established according to the bearing characteristics of hydraulic support and immediate roof. The results show that the roof deflection is positively correlated with the working face length, and with the increase of the working face length, the roof deflection in more areas has a larger value and it gradually changes from a single peak to multiple peaks. The roof stability decreases with the in-crease of the working face length and the decrease of length-thickness ratio. The research results are verified in working faces of different lengths in Buertai Coal Mine, and the phenomena of roof caving in different regions and asynchronous weighting in the face are explained. This study at-tempts to provide a theoretical basis for the roof treatment of super-long working faces.