WEBNov 12, 2020 · Stressstrain curves of coal from unloading tests under different confining pressures As shown in Fig. 5, the recovery of deformation and permeability occurs in the coal sample with the unloading ...
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.
WEBSep 24, 2022 · Effect of Cyclic Loading and Unloading on the Deformation and Damage Properties of Sandstone from Beizao, a Coal Mine underneath the Bohai Sea in China September 2022 Geofluids 2022(3):111
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 .
WEBOct 31, 2019 · During the loading/unloading process, the gas pressure in the coal sample is maintained constant through the ingenious structure design of the system. As shown in Fig. 2 b, the constantvolume chamber is connected to the sample by a gas tube, and the constantvolume pistons are connected to the axial indenter.
WEBFeb 1, 2014 · To comprehensively understand the differences in mechanical behavior of coal during the mining process at different depths, cyclic triaxial loading and unloading (CTLU) experiments with acoustic ...
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.
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 .
WEBMar 7, 2021 · In coal mining activities, the abutment stress of the coal has to undergo cyclic loading and unloading, affecting the strength and seepage characteristics of coal; additionally, it can cause ...
WEBDec 1, 2019 · This loadingunloading process can also occur in roomandpillar mines as the cascading pillar failure occurs. Fig. 1 (c) shows a series of gascontained pillars each subject to the same tributary area loading. If one of the weak pillars fails (Fig. 1 (c1)), the load will transfer to neighboring pillars causing an abrupt pillar loading .
WEBJan 7, 2024 · 5. Signage and Communiion: Clear and visible signage plays a crucial role in promoting safety during loading and unloading activities. Signage should indie designated loading zones, maximum load capacities, and potential hazards. Effective communiion between workers, drivers, and other personnel involved in the process .
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 ...
WEBApr 5, 2021 · For example, in the loading and unloading process, much elastic energy accumulates in the coal and rock mass with increasing elastic deformation. Under unloading, elastic energy is released. In the test process, the total energy density and elastic energy density of the coal mass can be expressed as Formulas ( 2 ) and ( 3 ).
WEBNov 15, 2018 · Abstract and Figures. In this article the process of coal unloading from the face's fracture zone to the conveyor using shearer drums is presented. The effect of the form and dimensions of the ...
WEBSep 19, 2023 · This paper presents two experimental schemes, graded cyclic loading and unloading, and variable lower limit cyclic loading and unloading, to investigate the energy evolution and acoustic emission characteristics of rocks under different cyclic loading and unloading paths. The experiments were conducted using a WAW300B microcomputer .
WEBDec 15, 2023 · A novel permeability model under triaxial pressure loading–unloading was developed. • The influence of effective stress and adsorption/desorption is considered in model. • The model is verified using test results of coal seepage under three conditions. • Triaxial pressure loading–unloading has a significant effect on coal permeability.
WEBOct 26, 2023 · This indies that during the whole cyclic loading and unloading process under confining pressures, the sample can maintain good elastic properties in the direction of the maximum principal stress. ... Chen HD, Cheng YP, Zhou HX, Li W (2013) Damage and permeability development in coal during unloading. Rock Mech Rock Eng .
WEBJun 1, 2015 · To simulate the unloading process of cemented backfill in the deep highland environment of coal mine, triaxial unloading confining pressure tests of cemented coal gangue fly ash backfill at different unloading rates after curing at different temperatures (20 ℃, 35 ℃ and 50 ℃) were carried out by the Rock Triaxial Testing System, and the ...
WEBIn actual mining situations, the advancing speed of the working face is usually accelerated, which may affect the failure and seepage characteristics of gasbearing coal, and may even induce dynamic disasters. In order to discover the effects of such accelerated advancement of the working face, an experimental study on the failure and seepage .
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 ...
WEBSep 1, 2018 · However, the loading and unloading rates have an important influence on the mechanical properties of the coal, and are closely related to the excavation steps of the working face. During an actual excavation process in a coal mine, the coal miners often reduce the excavation steps in order to prevent coal and gas outburst.
WEBFeb 8, 2019 · Rock burst is a astrophic dynamic disaster caused by sudden failure and instability of coal, loading paths play an important role in the failure of coal, the coal failure process is associated with charge exception information. Hence, violent coal failure mechanics and time–frequency domain distribution of charge signal such as rock burst .
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 ...
WEBAug 12, 2021 · The coal burst is a violent failure process induced by unloading the coal seam which had been subjected to the high insitu stresses. During the unloading process, the energy stored in the coal seam and surrounding rock release rapidly, usually leading to rock burst. ... Many factors can trigger the coal burst,, the dynamic load .
WEBSep 26, 2023 · The rock mass in fault zones is frequently subjected to cyclic loading and unloading during deep resource exploitation and tunnel excavation. Research on the mechanical and hydraulic characteristics of fault rock during the cyclic loading and unloading is of great significance for revealing the formation mechanism of water .
WEBFeb 1, 2024 · In the process of coal seam mining, the coal is disturbed by periodic pressure. This disturbance can be simplified to the loading process under different stress environments [5], [9], [10], [45], and the characteristics of the mining stress path are different under different advancing speeds [46]. Fig. 3 shows the loading path of the .
WEBNov 20, 2022 · The paper represents a test investigation of the mechanical properties and acoustic emission (AE) characteristics of lowstrength coal specimens subjected to cyclic loading and unloading. From the lab tests, the following conclusions can be obtained: (1) The axial strain is very well linear with the loading–unloading cycle number, and the .
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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