WEBMar 20, 2023 · In the process of coal formation, the internal structure is different from the occurrence of primary cracks. As a result, the new crack generation and primary crack development of different samples are affected to different degrees during loading and unloading. Energy characteristics under true triaxial loading and unloading
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WEBDec 3, 2021 · As a result, the crack of saturated coal samples cannot keep stationary in the initial stage of loading and unloading and it slips throughout the loading and unloading process. A large number of macrotensile cracks appeared in the failed coal samples with pore water, as the pore pressure provides tensile force to the cracks and promotes the ...
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WEBResearch on energy and damage evolution patterns of gascontaining coal under constricting pressure unloading conditions is urgently needed in the process of deep underground mining and is crucial for understanding the mechanisms underlying coal and gas composite rockburst occurrences. Prior reaching peak stress, cyclic loading and .
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WEBFeb 1, 2019 · the pressure loading and unloading process was explained theoretically based on a tight fourparticle packing unit, whic h provides a reasonable explanation for the experimental results
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WEBUnloading and loading freight happens so often that workers and management can become complacent to the inherent dangers that exist in the process. Unloading and loading freight is almost always under some sort of time constraint. This issue and tighter supply chain windows can exacerbate the problem and create an even more dangerous .
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WEBJan 1, 2018 · During the process of deep coal mining, coal seams are generally under the true triaxial stress state (σ1>σ2>σ3), which is influenced by the crustal stress and strong excavation disturbance.
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WEBFeb 15, 2014 · By using RMT150B rock mechanics test equipmentthe acoustic emission(AE)tests of coal specimen under conventional triaxial and triaxial cyclic loading and unloading were carried outand AE characteristics of coal specimens under different loading situations was test results show that the AE mutation point in .
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WEBSep 1, 2017 · The mining of coal resources causes the stress on the front and both sides of the working face to be in a complex loading and unloading process, and the gas contained in the coal body migrates ...
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WEBApr 1, 2017 · In underground operations, the coal cutter cut the coal seam, and large coal blocks were cut off from the coal wall. Then, the coal blocks were transported to the laboratory and processed into cylindrical specimens with diameters of 50 mm and lengths of 100 mm in accordance with the ISRM standard (Fairhurst and Hudson, 1999).The .
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WEBMay 14, 2024 · This study investigates the stability of an artificial dam used in an underground reservoir in a coal mine under periodic weighting imposed by overlying rock strata. For this purpose, cyclic loading and unloading tests with different stress amplitudes were designed. Differences in the mechanical performance of the artificial dam with and .
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WEBFeb 1, 2021 · The samples collected from Banxi coal mine in Chongqing, Southwest China, have been used to study on damage of coal based on permeability change rate (PCR) and loadunload response ratio (LURR ...
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WEBSep 1, 2022 · The mining of coal resources causes the stress on the front and both sides of the working face to be in a complex loading and unloading process, and the gas contained in the coal body migrates ...
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WEBMar 29, 2024 · Conventional triaxial loading and unloading test scheme. A substantial amount of research indies that the stress distribution in the overlying strata in front of the coal face can be divided ...
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WEBDec 1, 2020 · Fig. 9 shows that coal rocks with fracture networks of different levels of complexity all undergo essentially the same permeability evolution process under loadingunloading conditions, although differences in the final increase in permeability can be observed. The higher the complexity of the initial fracture structure is, the higher the final ...
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WEBSep 1, 2020 · The energy evolution and fragment distribution characteristics of different types of rocks were investigated through the uniaxial cyclic loading and unloading experiments for granite, redsandstone, coal, gypsum, and highwater material. Based on the results of the study, the following conclusions are drawn.
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WEBFeb 20, 2020 · Loading and Unloading Elastic Modulus. Coal is a porous medium that is affected by the geologic environment during the formation process. Coal contains a large number of primary pores and microcracks, resulting in coal being a .
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WEBJul 11, 2022 · The change of elastic modulus of coal samples with the moisture. content of % is the largest in the first and sixth cyclic loading–unloading, decreasing. Mpa and Mpa ...
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WEBJan 22, 2024 · Protective seam mining is the most economical and effective measure for eliminating coal and gas herniation. To study the unloading effect of the mining of a protective seam on the protected layer, and to better grasp the effect of the protective layer on the abatement, conventional triaxial tests were conducted on coal samples with the .
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WEBSep 1, 2017 · From the perspective of mechanics, coal mining is a loading and unloading process. The typical underground loading and unloading features are mainly distributed on the front side and the protective layer. These loions are often in a complex stress environment. The main variation of the force is shown in Fig. 1. It shows that the force ...
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WEBJun 26, 2023 · Coal mining often causes periodic disruption in the rock mass around the stope. The study of the deformation and failure characteristics of cyclic loading and unloading sandstone is very critical for gaining a thorough understanding of the mechanisms of rock damage, degradation, and failure. This kind of investigation is very .
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WEBJun 28, 2023 · Some of the activities related to loading and unloading include: Loading. Loading involves the process of loading cargo into a transport vehicle, such as a truck or container. This involves efficiently and safely managing loads within the vehicle to prevent damage or loss during transportation. Demolition. Unloading is the activity of removing ...
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WEBJan 1, 2011 · Introduction At present, coal is the preeminent fuel of thermal power plant. Continuing up the large unit, and large capacity, the demand of coal is very large. Coal need to process from loading and unloading to stockpile, this procedure can finish by coal conveying system.
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WEBAug 1, 2019 · The results showed that the change trend of permeability was negatively correlated with the confining pressure in the process of loading/unloading of coal and it was divided into three stages for ...
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WEBJun 1, 2019 · The fitting formulas of coal sample axial and radial permeability values under three loading/unloading cycles are shown in Table 5. In Table 5, subscripts A and R respectively denote the axial and radial permeability of coal samples; L and U denote loading and unloading, respectively; and 1, 2, and 3 refer to the number of .
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WEBJun 1, 2019 · (3) During the loadingunloading process of confining pressure, the permeability of coal containing gas is damaged to a certain extent and this damage can be represented by the maximal damage rate ...
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A material supplier from Belgium would like to produce limestone powder for his custome...
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