Study on failure mechanical characteristics and damage constitutive model of sandstone with different numbers of holes

Abstract

The existence of holes in rock is one of the key factors for the instability of underground rock mass engineering. Combined with acoustic emission equipment, uniaxial compression tests of rock specimens with different numbers of holes in the rock were carried out. The results show that with the number of holes increases, the value of peak strength and elastic modulus of the rock decrease. The acoustic emission (AE) counts gone through stable, slow increase, a sudden increase and towards zero four stages and there are corresponding to the initial compaction stage, elastic stages, strain hardening stage and post-peak strain softening stage of the stress-strain curves approximately. Based on the AE events, damage variables of rocks were obtained. The damage evolution process of rock can also be divided into three parts, including stable damage stage, slowly increasing damage stage and sharply increasing damage stage. According to Duncan model, the damage variable is introduced to obtain the rock damage constitutive model. No matter it is the pre-peak initial compaction stage, the linear elasticity stage, the strain hardening stage or the post-peak strain softening stage, the fitting curves are in good agreement with the test curves. It also illustrates the rationality of the damage constitutive model.

Development of a Model for Initial Compaction Stage in Rock Based on Energy Dissipation

“…In the present study, the experimental stress-strain curves under the uniaxial compression in five types of rocks were extracted to study the initial compaction stage, based on the earlier studies [27][28][29][30][31]. Initially, the deformation characteristics and the energy evolution mechanisms during the rock failure process were investigated.…”

Research on mechanical properties and acoustic emission characteristics of rock beams with different lithologies and thicknesses

“…AE (Acoustic Emission) test is a very effective method to study the fracture of rock beams. It has significant effects on the research of crack propagation (Bing and Einstein 2017;Du et al 2018;Cao and Liu 2020), damage mechanism (Wu et al 2020) and failure precursor information (Guo et al 2019b;Guo et al 2019c) of rock beams. Zhang et al (2019) analyzed the damage evolution mechanism of limestone beams based on the AE characteristics under bending load.…”