Effect of Loading Rate on the Mechanical Properties of Weakly Cemented Sandstone

Abstract

Weakly cemented rocks are characterized by low strength, loose structure, and easy disintegration. High-intensity mining activities can damage and rupture such rock bodies and induce damage, such as flaking and roofing on roadways. To reveal the mining intensity influence on the weakly cemented rocks’ deformation and damage, a numerical particle flow model of weakly cemented sandstone was established based on particle flow theory. Uniaxial compression simulation tests were conducted at four loading rates of 0.01, 0.1, 0.5, and 1 mm/min to study the weakly cemented sandstone’s stress–strain relationship, damage rupture, acoustic emission, and energy evolution. The results show that, with an increased loading rate, the uniaxial compressive strength of weakly cemented sandstone increases exponentially, and the rupture mode transforms from brittle damage to ductile damage; the greater the loading rate, the greater the degree of damage and crushing range of the rock. Further, with an increased loading rate, the peak hysteresis of rock acoustic emission events decreases, and the number of events increases; the energy accumulated in the rock increases, thus intensifying the degree of rock damage. Therefore, the possibility of engineering disasters should be considered when conducting high-speed underground mining activities.