Experimental study of the influence of structural planes on the mechanical properties of sandstone specimens under cyclic dynamic disturbance

Abstract

Discontinuity-controlled slopes constitute potentially fatal risks during exploitation activities in open-pit mines and severely threaten the safe mining of collieries. To investigate the dynamic mechanical properties of rock with structural planes under periodic cyclic dynamic disturbance, this study took the north side of the Anjialing open-pit mine as an example. Uniaxial compression tests were carried out on rock samples containing structural planes with different dip angles (θ). The impacts of θ on the strength, deformation characteristics, energy dissipation characteristics, and fracture rules of rock samples under different disturbance stress amplitudes (Δσ) are studied. The test results show that the structural plane affects the mechanical properties of rocks under dynamic perturbation. A closed hysteresis loop curve of rock is formed in each loading and unloading cycle, thus forming three stages: a sparse stage, a dense stage, and another sparse stage. θ, Δσ, and the number of disturbance cycles (n) impact the rock hysteresis loop curve and deformation modulus. The plastic deformation of rock mainly includes an initial deformation stage, an isokinetic deformation stage, and an accelerated deformation and overall failure stage. Moreover, there is a disturbance threshold for Δσ′ of the rock failure, and the evolution law of plastic strain accumulation and n near the disturbance threshold conform to the negative exponential function and the inverse function of the Langevin function, respectively. Based on damage theory, a constitutive model of the structural plane considering a disturbance threshold is proposed.