A uniaxial compressive dynamic damage model for rockmass considering the crack roughness

In order to take into account the influence of the crack roughness, first of all, on basis of the calculation model for the rockmass macroscopic damage variable which can take into account the crack geometry parameter, strength parameter and deformation parameter, a calculation model for the rockmass macroscopic damage variable is proposed by introducing the JRC-JCS shear strength model for the rough crack established by Barton, which can consider the crack roughness. Secondly, the proposed calculation model is introduced into the uniaxial compressive dynamic damage model for the rock mass with the non-persistent crack, which both considers the coupling of the macroscopic and microscopic defects, and then a uniaxial compressive dynamic damage model for the rock mass with the non-persistent crack is established which can consider the crack roughness at the same time. Finally, the effect of crack roughness JRC and crack basic friction angle φ_b and crack length 2a on rockmass dynamic mechanical property is studied with the parametric sensitivity analysis. The result shows that the rockmass dynamic climax strength increases from 26.42 MPa to 27.28 and 28.37 MPa with JRC increasing from 0 to 10 and 20 respectively. The rockmass dynamic climax strength increases from 26.24 MPa to 27.28 and 28.80 MPa with φ_b increasing from 0° to 15° and 30° respectively. The rockmass dynamic climax strength decreases from 31.37 MPa to 27.28 and 23.90 MPa with 2a increasing from 1cm to 2 and 3cm respectively. At the same time, in order to describe the influence of the crack roughness more accurately, the crack fractal dimension is introduced into the dynamic damage model for the rock mass, which not only improves the calculation accuracy of the model, but also broadens its application range, which is more convenient for practical engineering application.