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Copyright of Food & Machinery is the property of Food & Machinery Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on the open-pit and underground mining engineering practice in Pingshuo mining area，the physical simulation and numerical analysis were combined to investigate the deformation-failure characteristics and stress distribution rule of mining slope. Therefore，the deformation-failure mode and the typical instability mechanism of mining slope under the coupling effects of key hard strata and key weak strata were revealed. A four-stages theory of deformation and destruction of mining slope was put forward，including epigenetic recreation of rockmass structures stage，structure transformation stage，time-dependent deformation stage and eventually unstable (stable) stage. Then the engineering mechanics model was established.The criterion of mining slope into the time-dependent deformation stage and eventually unstable (stable) stage were deduced. [ABSTRACT FROM AUTHOR]

A new type of metal support named H-Shaped members with corrugated webs was proposed to be applied in the metal support structure of the mine roadway. Through the experimental study combined with the finite element numerical simulation, the stability behaviors of this type of supporting structure with corrugated webs were studied. The model tests on two straight wall semicircle arch with corrugated webs were designed to obtain the failure mode, the strain and the displacement development rules of the support, and the influence of flange thickness of corrugated steel web on the supporting capacity is analyzed. The results showed that the failure mode of the corrugated steel webs was global asymmetric buckling, when the flange thickness of the corrugated steel webs was increased from 12 mm to16 mm,increased by 33%, the bearing capacity of the support increased by 27.38%. It showed that the thickness of flange has a significant influence on the bearing capacity of the support. And the finite element model was verified by comparing the experimental results with finite element analysis. At the same time, the finite element method was used to compare the I-steel for mining with the corrugated web support with the same steel consumption. The results showed that the bearing capacity of the corrugated web support was 31.68% higher than I-steel for mining, and the deformation was about 4/5 of I-steel for mining. Through the numerical simulation of the influence of various parameters of the section of corrugated steel web support on the elastic and elasto-plastic buckling load of the support, it was found that the height and thickness of the web are more sensitive parameters. The supporting performance of the corrugated webs support and I-steel support for mining were respectively analyzed under the hydrostatic pressure, vertical unidirectional stress and vertical force.Results showed that with the same steel consumption, the corrugated web support had higher shearing capacity, and it was not easy to undergo buckling even if it had high height-to-thickness ratios.In addition, it was flexural and the axial stability capacity could also be greatly improved since the steel consumption was concentrated on the flanges. Therefore, the deformation of the corrugated web support was less than the mining I-steel support, and the supporting performance of the corrugated supporting was superior to I-steel support under various load conditions. [ABSTRACT FROM AUTHOR]

To overcome the water inrush problem of working face at Dongjiahe coal mine, a microseismic monitoring system was installed to analyze the microcrack data from baseplate of fault zone. The initiation and evolution process of microcracks in baseplate was reconstructed during the working face passes through the fault. Also, the microcrack data was combined with Realistic Failure Process Analysis( RFPA2 D) system to study the variation law of stress fields during the evolution process of water-conductive fissure zone in wall rocks of baseplate fault. The results showed that:① according to the analysis of microseismic event distribution, microcracks occurred when working face is 85 m ahead of the fault. The depth of microcracks in baseplate reached 25 m before working pace passing through the fault and the baseplate has a sectioned local failure characteristics. After working face passing through the fault, the maximum depth of microcracks reached 35 m and microcracks are gradually transfixed. ② According to the analysis of microseismic energy density distribution, the concentration zone of high energy density before passing through the fault was about 15 m in strike length, and located in 5-25 m beneath the coal layer. Meanwhile, the fault located within 5 m range of coal layer remained stable. After passing through the fault, the high energy zone expanded to upper goaf and deeper zone, to around 80 m range into the upper goaf along the working face, and around 35 m range beneath the coal layer. ③ According to the microseismic monitoring and numerical simulation results, the expansion process of baseplate water inrush tunnel could be divided into two phases as before passing the fault and after passing the fault. Before passing the fault microcracks occurred initially in the wall rocks of fault around 25 m beneath the coal layer, and expanded through the fault. There were microcracks occurred in 5-25 m beneath coal layer but not yet transfixed. After passing the fault, the microcracks expanded from top to bottom and formed a water inrush tunnel. ④ According to the analysis on the evolution law of fault stress based on numerical simulation, before passing the fault, the shear stress of the fault was a negative value and gradually decreasing. The upper part of the fault tended to slip downwards. The greater the depth the faster the shear stress reached its extremum, resulting in a compression and shear failure in wall rocks from bottom to top. Upon the working face reached near the fault, the shear stress reversed rapidly and reached its maximum. The upper part of the fault tended to go upwards under the action of confined water. The surrounding rocks had a pull failure from top to bottom, and cracks gradually transfixed, forming a water conductive tunnel. [ABSTRACT FROM AUTHOR]