Failure Characteristics of Fractured Coal and Rock Under the Condition of Different Angles Structure Plane

In order to research the structure plane effect of coal and rock mass, choose the typical coal and rock sample, prefabricate specific length, different angles of single crack in coal and rock sample surface, using the CRIMS-DDL600 electronic universal testing machine, the strength, deformation characteristics, and failure modes of structural plane angle effect of coal and rock sample with single fissure are studied by triaxial cyclic loading and unloading tests. The tests results show that the loading and unloading path of stress-strain curve does not overlap, a number of closed loops-loading and unloading elastic hysteresis loop are formed, the change characteristics of the envelope of stress-strain curve similar to monotonic loading, the irreversible deformation of sample is in nonlinear increase tendency with the increasing number of cycle, the compressive strength of specimens decreases continuously with the increase of structural plane angle when structural plane length is determined.