Mechanical properties and crack propagation of discrete distribution non-persistent jointed rock masses under uniaxial compression

Fractured rocks as typical engineering materials are commonly influence by distinct arrangement of joints and the angle of their inclination. In this paper, uniaxial compression test were carried out on three kinds of marble samples (a-series, b-series and c-series) containing different dip angle (30◦, 45◦, 60◦ and 75◦). Subsequently, strain gauge and high speed camera were used to monitor the micro fracture and the change of surface strain, and scanning electron microscopy (SEM) was also used to study the morphology of marble. Thereafter, numerical simulation of the fractured rocks based on the discrete element method were investigated. The rock mass's failure trajectory, mode of failure were investigated in the experiment, and the distribution of PFC cracks, their displacement, the spread of prefabricated cracks, and the manner of their failure under simulated scenarios were investigated in the simulation. Additionally, an examination was conducted on the damage and its constitutive curves for the three marble varieties, along with an analysis of the connection between the initial damage and the distribution of joints. The results demonstrate that the gradient of the fissure plays a role in determining the durability of marble. The numerical simulation reveals an enhancement in both the maximum strength and the elasticity of the crack correlating with the crack's rising dip. The stepped, coplanar and rotational failure modes in rock mass were proposed utilizes a blend of experimental and simulated data. Damage constitutive model resembles the stress-strain curve's pre-peak curvature, during the post-peak stage of the stress-strain graph, the decrease in stress becomes more pronounced and fragile.