Abstract
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.
Highlights
The rock mass is a naturally formed heterogeneous brittle material
In order to study the influence of the number of holes on the mechanical characteristics of rocks, uniaxial compression mechanical tests on rock specimens with different numbers of holes were carried out, and the acoustic emission events were monitored during the experimental
The acoustic emission (AE) counts gone through stable, slow increase, a sudden increase, and towards zero four stages and these four stages are corresponding to the initial compaction stage, elastic stages, strain hardening stage, and post-peak strain softening stage of the stress curves approximately
Summary
The rock mass is a naturally formed heterogeneous brittle material. Due to the influence of geological structure, the rock mass contains weak structures such as rich cracks and holes. The results show that the size and shape of the pores affect the strength of the rock and the fractal law These studies mainly analyze the propagation of cracks around the holes, there are few studies on the influence of the number of holes on the mechanical properties of rocks. It can be seen that acoustic emission characteristics have been maturely applied in rock mechanics(Guo, Q., et al.,2020a) It is a very important monitoring method to evaluate rock damage. The effect of holes on the mechanical characteristics of rock failure is analyzed, the AE events of rock with different number holes are analyzed, and the damage constitutive model of rock with holes is further analyzed These studies are of great significance for understanding the damage of rock masses
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