The Influence Analysis of Upper Liberation Layer Mining on Roadway Stability of Fully Mechanized Caving Face

The numerical simulation software UDEC is used to simulate the effect of upper liberation layer mining on roadway stability of fully mechanized caving face. According to the analysis of the vertical stress of liberated layer and the surface displacement of the tunnel, this paper got conclusions that the vertical stress of coal on the liberated layer can be divided into four areas, initial stress area, stress-increased area, stress-decreased area and stress recovery area after mining the liberation layer, besides, the effected of liberation layer mining on roadway decreases effectively. And the results are in good agreement with the field measurements.