Study on Central Symmetry Controlling System for Cable of Large Span Open-off Cut at Fully Mechanized Caving Mining Face and Its Application

For the problem of surrounding rock control problem of large span open-off cut at fully mechanized caving mining face, we use UDEC4.0 to simulate and analyze the deformation and failure features of surrounding rock. The analysis result shows that the plastic zone of thick top coal is the arch shape and the plastic zone of floor is the inverted trapezoidal shape. And the increase of open-off cut width is the most sensitive to the range of roof plastic failure, but the least to floor. The shortcomings of original support scheme are pointed out in this paper. On the basis of the analysis results, the central symmetry cable support technology of truss cable and sing cable is proposed to control the surrounding rock. The truss cable and sing cable in the system are considered to be anchored on the both sides of arch roof in the stable zone which could constrict the development of plastic zone with stress arch in roof coal. Field practices show that the support program can control the deformation of surrounding rock.