Mechanical behavior of coal under different mining rates: A case study from laboratory experiments to field testing

Gao, Mingzhong; Xie, Jing; Gao, Yanan; Wang, Wenyong; Liu, Cong; Yang, Bohan; Liu, Junjun; Xie, Heping

doi:10.1016/j.ijmst.2021.06.007

Cited by 217 publications

(57 citation statements)

References 43 publications

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“…10. Generally, the stress-strain curve presents a progressive failure process from compaction, elastic deformation, stable crack propagation, accelerated crack propagation, and post-peak deformation (Gao et al 2021;Sha et al 2020). The compaction deformation is represented by the initial upward concave part of the curve and may be associated with the asperities and voids on the surface (Korinets and Alehossein 2002).…”

Section: Stress-strain Curvementioning

confidence: 99%

Effect of water content on the mechanical properties of an artificial porous rock

Jiang

Chen

et al. 2021

Bull Eng Geol Environ

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Water content significantly affects the mechanical properties of porous rocks, for which both clay content and rock microstructure have been identified as main controlling factors. To study the influence of microstructure on the water effect on rock properties, artificial porous rock (APR) is made by heating Fangshan granite (FG). The mineral composition and microstructure of the thermally treated FG were determined, and 1000 °C was chosen as the treatment temperature to fabricate the APR. APR specimens with various water saturations (100%, 80%, 60%, 40%, 20%, and 0%) were prepared by drying fully saturated APR specimens. The quasi-static responses of the APR specimens during uniaxial and triaxial compression (with confining pressures of 5 MPa and 10 MPa) experiments were obtained. The results show that the uniaxial compressive strength (UCS) of the APR slightly increases with increasing water saturation from dry (0% saturation) to 60% saturation, and the cohesion shows a similar trend. However, the triaxial compressive strength decreases with increasing water saturation. The cohesion and internal frictional angle were obtained from the compression tests, and their dependence on the saturation was revealed, which can be explained by the interaction of the water and the rock microstructure. Keywords Heat treatment • Artificial porous rock (APR) • Water content • Water weakening mechanism • Saturation List of symbols APR Artificial porous rock CPL Cross polarized light CT Computed tomography FG Fangshan granite ISRM International Society for Rock Mechanics and Rock Engineering LVDT Linear variable differential transducer PPL Plane polarized light SEM Scanning electron microscopy UCS Uniaxial compressive strength n Porosity of rock specimen V v Pore volume of rock specimen (cm 3 ) V Bulk volume of rock specimen (cm 3 ) S r Degree of saturation (%) V w Volume of water (cm 3 ) f Ultimate shear stress (MPa) nor Normal stress (MPa) C Cohesion (MPa) Internal friction angle (°) F m Resisting stress of the meniscus effect w

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Section: Stress-strain Curvementioning

confidence: 99%

Effect of water content on the mechanical properties of an artificial porous rock

Jiang

Chen

et al. 2021

Bull Eng Geol Environ

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“…In laboratory tests, the characteristics of rock failure precursors can be discussed from a macrocosm and a microcosm point of view. In the macroscopic aspect, failure precursor characteristics of stress, strain, and macro-failure morphology are analyzed, while energy, crack (Gao et al, 2021a;Gao et al, 2021b), infrared thermal image, acoustic emission, and other auxiliary means are used in the microscopic aspect. Among them, acoustic emission (AE) monitoring can be used to evaluate rock damage by detecting the location, direction, and size of AE sources during rock deformation and failure (Liu et al, 2014;Du et al, 2020;Yang et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Research on Failure Precursor Based on Characteristics of Energy Dissipation Rate for Rock

et al. 2022

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Research on early warning of rock disaster based on the energy theory is closer to the essence of rock failure. In this paper, static compression tests and acoustic emission (AE) tests of coal rock under 0, 8, 16, and 25 MPa confining pressures were carried out on the MTS815 test system. Energy evolution law in the rock failure process was analyzed according to the relationship between mechanical parameters, AE parameters, and energy dissipation rate (EDR) in the rock failure process. Eventually, a new index for evaluating rock failure precursors was proposed based on EDR. The results show that the EDR has a good correlation with mechanical strength and AE events under different confining pressures. The deformation and failure characteristics of coal rock can be truly characterized by EDR. The variation of EDR can be divided into a quiet stage, a stable increasing stage, an active stage, and a stable stage. The EDR level in the quiet stage is obviously enhanced by confining pressure. When EDR reaches the peak, AE events increase rapidly. In the active stage, the EDR peak value is concentrated and large, the AE event is highly active, and stress drops abruptly, indicating that the EDR is reliable for evaluating the rock failure process. Compared with AE test results, it is found that the warning stress and warning time of the EDR failure precursor occur later than that of the AE failure precursor, and the former is closer to the peak stress of rock, which is more universal in engineering and could provide a better reference value for preventing rock disaster.

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“…Witherspoon [6] proposed the cubic law derived from the ideal smooth parallel plate model, which has been widely used in the study of flow law of fractured rock mass [7,8]. Scholars have carried out flow experiments of smooth parallel plate fractures, and the experimental results have proved the rationality of the cubic law, that is, the fracture discharge is proportional to the cubic power of the crack width [9,10].…”

Section: Introductionmentioning

confidence: 99%

Flow characteristics of fractal fracture with different fractal dimension and different fracture width

et al. 2021

Self Cite

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Single fracture is the most basic element in complex fracture network of rock mass. Therefore, the study of flow characteristics of single fracture is an important way to reasonably predict the complex flow state in engineering rock mass. In order to study the flow characteristics of fractal single fracture, fracture models with dif?ferent fractal dimension and different fracture width are established in this paper. The results show that: the blocking effect of rough structure on fluid is obviously enhanced under high pressure. In addition, it is weakened and reaches a steady-state with the increase of fracture fractal dimension. The larger the fracture width is, the more obvious the phenomenon is. The hydraulic gradient index tends to 0.5 with the increase of fracture width when fractal dimension is greater than 1.3. It also could tend to 0.5 with the increase of fractal dimension when fracture width is greater than 1 mm.

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Mechanical behavior of coal under different mining rates: A case study from laboratory experiments to field testing

Cited by 217 publications

References 43 publications

Effect of water content on the mechanical properties of an artificial porous rock

Effect of water content on the mechanical properties of an artificial porous rock

Research on Failure Precursor Based on Characteristics of Energy Dissipation Rate for Rock

Flow characteristics of fractal fracture with different fractal dimension and different fracture width

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