Research on the Influencing Factors of Roof Falling at the End Face of Composite Roof Based on UDEC
In response to the problems of easy roof falling at the end face and easy spalling of coal wall for the composite roof with large burial depth,taking the 7242 working face of Suntuan Coal Mine as the background,theoretical calculation and numerical simulation methods were used to study the influence rules of roof falling at the end face from three aspects,including end face distance,support working resistance,and roof cohesion.The research results indicate that end face distance is the main factor affecting roof falling at the end face,and reducing end face distance can reduce the development of roof fracture and improve the roof stability at the end face.The support working resistance indirectly affects the roof stability at the end face,and the magnitude of the support working resistance is negatively correlated with the height of fracture development in the roof and the occurrence of roof falling accidents.Rock masses with high cohesion have a positive effect on improving the roof stability at the end face.Finally,based on the results,targeted stability control measures have been proposed,such as increasing the support working resistance to 6800 kN,controlling the end face distance to 0.3 m,and timely maintaining the stability of roof and coal wall.The application results verified that the proposed measures can ensure the roof stability of the end face.
Composite roofRoof falling at the end faceFracture developmentEnd face distanceRoof stability