Deformation and damage dynamic characteristics of coal–rock materials in deep coal mines

Abstract

The deformation and damage characteristics of surrounding rock grow gradually with the increase of mining depth, and the mechanical behavior and damage mechanism of coal–rock materials vary greatly. In order to reveal the deformation and damage dynamic characteristics of coal–rock materials in deep mines, the macroscopic deformation characteristics of coal, rock, and concrete samples under uniaxial compression were studied. The macroscopic deformation amount, velocity, and acceleration of different samples were analyzed. The coal and rock samples exhibit regular dynamic characteristics before they lose stability and fail. The axial strain response of the coal samples changes significantly during the compact and elastic deformation stages. Besides, the relationship between the surface damage and the macroscopic deformation of sample was studied by means of visualization and image processing. The macroscopic deformation index of coal–rock materials changes significantly before and after the destabilization and failure. Based on the deformation and failure dynamic characteristics of coal and rock, the evolution rule of deformation critical values was taken as the deformation and destruction stages, which revealed the dynamic characteristics during the deformation and failure process of coal–rock materials in deep mines. The deformation critical values can be used to realize early warning of deformation and fracture of coal and rock materials in deep mines.

Acoustic Emission Experimental Research of the Damage Characteristics of Raw Coal under Different Loading and Unloading Rates

“…e coal samples selected for this experiment ( Figure 3) were taken from Jixi Mining, Chengshan Coal Mine. e mining area is approximately 8.2 km long from east to west and 3.5 km wide from north to south and covers an area of 37.8889 km 2 . In accordance with the requirements of the regulations, the coal samples were processed into standard coal samples with a diameter of 50 mm and a height of 100 mm.…”

“…As China's shallow resources are becoming exhausted, more mines are beginning to excavate deep. e deformation and damage characteristics of surrounding rock gradually grow with the increase in mining depth, and the mechanical behavior and damage mechanism of coalrock materials immensely vary [2]. e rock is in a state of three-way stress balance before excavation.…”

The effect of cross-section shape on deformation, damage and failure of rock-like materials under uniaxial compression from both a macro and micro viewpoint

“…Rock-like materials are very common in our daily life, and their mechanical properties have been extensively studied so far (Huang and Yang, 2019; Jacobsson et al., 2015; Quinones et al., 2017; Shahsavari et al., 2019; Wu et al., 2019; Xu et al., 2019), which are conducive to utilizing their full potential, avoiding unnecessary losses and solving engineering problems (Chen and Lin, 2019; Chen et al., 2019; Guo et al., 2019; Lin et al., 2019a, 2019b; Wang et al., 2017, 2018, 2019; Zhang et al., 2014, 2019; Zhao et al., 2017a, 2017b, 2019). The uniaxial compression of rock-like materials has always been a hot topic and is often encountered in engineering practice, such as underground pillars and concrete columns.…”

An improved nonlinear damage model of rocks considering initial damage and damage evolution

“…Based on the lab test results, the creep characteristics of different rocks have been revealed and discussed extensively (Hadiseh and Rassoul, 2018; Lu and Zhao, 2016; Wang et al., 2014a; Wu et al., 2018; Xu et al., 2019; Zhang et al., 2012a). According to the creep test results, a series of elasto-viscoplastic creep models have been established under different stress conditions.…”