Compound Roof Rockburst and Instability Mechanism and Joint Control Principle in Deep Coal Roadway

In view of rock burst and instability problems of compound roof in deep coal roadway under the action of high static loading and thick hard strata fracture dynamic load, the theoretical analysis shows that the starting condition of rock burst and instability of compound roof is the sharply overrun of rock beam bearing, deformation and energy storage capability. The studies show that the rock burst and instability process of roof was closely related to six main macroscopic control fissures cooperatively extended from "one transverse fissure and five longitudinal fissures" mode, which turns roof into the vicious circle of "interlayer separation - rock beam cracking - power shattering" or even instant caving. Structural joint control and reinforement can inhibit the rock burst and instability of roof by the advanced use of "high strength truss and anchor rope at the top of roof - inclined rock bolt at vertex angle- long anchor cable acrossing central roadway".