Study on the Relations between Roof Shallow Strata Type and Roof Caving Hidden Danger Level

In order to explore relationship between the different types of shallow roof, different structure combination of roof strata and the level of roof caving hidden danger. Based on roof stability partition method, using RFPA software, respectively on set a model about Soft-toughening type rock, Soft-brittle type rock, Medium-toughening type rock, Medium strength-Medium stiffness type rock, Hard-toughening type rock and Hard-brittle type rock, get the characteristics of roof deformation and failure at the condition of different types of rock. The results of the study show that the roof caving hidden trouble level of Soft-toughening type rock and Soft-brittle type rock is II level or above level II. The roof caving hidden trouble level of Medium-toughening type rock is will be I level, but Still mainly for II level. The roof caving hidden trouble level of Medium strength-Medium stiffness type rock, Hard-toughening type rock is belong to I level, II level. The roof caving hidden trouble level of Hard-brittle type rock is I level. Rock strength on the roof caving hidden danger level influence power is important than rock stiffness.