Research on creep disturbance characteristics and strength limit neighborhood of coal-rock combination body with different coal heights

In order to study the creep disturbance characteristics of coal-rock combination body with different coal body heights, the uniaxial compression creep disturbance test of coal-rock combination body was carried out by using the rock rheological disturbance effect test system, and the test results were verified by ABAQUS numerical simulation. The test results show that the thresholds of the three kinds of combination bodies with coal and rock mass height ratios of 1∶4, 1∶2 and 2∶1 entering into the strength limit neighborhood are 30 MPa, 25 MPa and 20 MPa, respectively, and the corresponding strength limit right neighborhood threshold widths are 5 MPa, 3 MPa and 2 MPa, respectively. The test results show that under the low stress level, the external disturbance does not have a great impact on the overall failure of the coal-rock combination body, while under the high stress level, the combination body is greatly affected by the external disturbance; the long-term strength of the combination body decreases with the increase of coal height, and with the increase of disturbance times, the whole combination body gradually changes from brittle failure to ductile failure; the coal-rock combination body is more sensitive to external disturbances when it only enters the strength limit neighborhood, and the higher the coal height, the more the number of disturbances, the lower the threshold of the combination body entering the strength limit neighborhood as a whole, and the smaller the threshold width of the right neighborhood of the strength limit.