Abstract
The damage and degradation are the main influence factors of the instability of rock mass engineering. In this paper, the damage and deformation characteristics of the rock-like samples are investigated under the uniaxial compression test, and the advanced digital image correlation (DIC) device is devoted to full-field deformation data acquisition on the sample surface. Based on the full-field deformation data, a new damage variable is proposed by the principal strain standard deviation to characterize the uniaxial compression damage process of the rock-like samples. The results show that the newly presented damage variable can be utilized for the quantitative characterization of the sample damage. According to the characteristics of the damage variable, the damage evolution process of the rock-like specimens under uniaxial compression can be divided into four stages: initial damage closure stage, linear elastic damage stage, elastic-plastic damage stage, and plastic damage stage. From the stress-strain curve, the cut-off point from elastic to plastic deformation of the rock-like specimen is also the turning point from micro to macro damage; after the point, the apparent initial damage starts to occur on the sample surface; furthermore, the damage of the specimen is accelerated in the plastic damage stage. When the overall damage variable reaches 0.5 or the damage variable of strain localization zone reaches 0.8, the macro crack forms, and the bearing capacity of the rock-like specimen decreases rapidly. The findings are of great significance to the prediction of the damage process of rock mass engineering by digital image correlation.
Highlights
With economic development in China, the construction of geotechnical engineering, such as dams, bridges, tunnels, and mining engineering, is in the ascendant. e damage and degradation of rock mass engineering are serious under complex occurrence conditions and stress environments
E concept of damage variable D was proposed by Krajcinovic for the first time [2]; a generality damage model was presented by Horii based on the previous research results, which made an important contribution to the quantitative description of damage evolution of rock and other solid materials [3]
Considering the influence of the occurrence environment on the deformation and damage process of rock [11, 12], the damage constitutive models of rock under the conditions of the freeze-thaw cycle, high temperature, and moisture were studied [13,14,15,16,17]. ese studies have laid a solid foundation for mastering the law of damage and failure of rock
Summary
With economic development in China, the construction of geotechnical engineering, such as dams, bridges, tunnels, and mining engineering, is in the ascendant. e damage and degradation of rock mass engineering are serious under complex occurrence conditions and stress environments. To investigate the damage process of rock, the volumetric porosity [27, 28] and accumulated plastic strain [29] are utilized to establish the damage variable combining the SEM. E mechanical behavior relationship between the micro and macro damage mechanisms of rock materials was investigated by observing the whole deformation and failure process with SEM [30]. E maximum shear strain, extracted on the samples with DIC, was used to establish a damage variable, which was utilized to describe the deformation and damage process of marble and slate with holes [31]. In this paper, based on the advantage of full-field strain measurement, the damage variable was defined with the main strain standard deviation for investigating the damage evolution process of rock-like samples. In this paper, based on the advantage of full-field strain measurement, the damage variable was defined with the main strain standard deviation for investigating the damage evolution process of rock-like samples. e findings are of great significance to the prediction of damage deterioration of rock engineering
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