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Wu Y.P.,Xi'an University of Science and Technology | Wu Y.P.,Key Laboratory of Western Mine and Hazard Prevention | Wu X.M.,Xi'an University of Science and Technology | Wu X.M.,Key Laboratory of Western Mine and Hazard Prevention | Chen Z.Z.,Shenhua Ningxia Coal Industry Group
Rock Mechanics: Achievements and Ambitions - Proceedings of the 2nd ISRM International Young Scholars' Symposium on Rock Mechanics | Year: 2012

Ningdong coalfield locates northwest meizoseismal areas. Rock mass in the coalfield is broken, unconsolidated and exists complicated stress zones. Thick seams distributed widely adopt mining method of high seam full extraction. Part Structural failure and phenomenon of strength degradation are often occurred. Based on investigations of in-situ geomechanics, lithology, mining condition and dynamic instability, key sections of deformation and unconsolidation intypical working rock mass isdetectedbydeep point displacement observation method and ultrasonic detection method, and then analyzed the rules of the deformation and instability. According to detection results and the knowledge of theoretical mechanics, multi-medium coupling support project is put forward. Styles and quantitative parameters of rational supports are ensured and estimated for their stability and safety. © 2012 Taylor & Francis Group.


Wen H.,Xi'an University of Science and Technology | Wen H.,Key Laboratory of Western Mine and Hazard Prevention | Guo J.,Xi'an University of Science and Technology | Guo J.,Key Laboratory of Western Mine and Hazard Prevention | And 6 more authors.
Chemical Engineering Transactions | Year: 2015

M engba coal is mined at a very high temperature and high humidity environment. Normally, the underground temperature is over 40 °C, and there are a large amount of water flows out from coal seams. To study the effects of water inflow on the characteristics of coal spontaneously combusted at 40 °C, the temperatureprogrammed experiments were carried out. Five different percentages of water content, which were 3.56%, 5.51%, 7.24%, 9.82% and 11.21%, were tested. Experimental results indicates that the coal samples with 9.82% and 7.24% percentages of moisture content could heat up to 40 °C fast, and continue to reach to 43 °C due to self-heating at the calorstat. On the basis of the temperature-programmed experiments, it was found that oxygen consumption rate, CO gas generation rate, and exothermic intensity coal samples with different percentages of the moisture content behave similar before the temperature less than 100 °C. The oxygen consumption rate, CO gas generation rate, and exothermic intensity of coal samples from high to low was in the order of 9.82%, 7.4%, 5.51%, 2,21%, 11.21%, and 3.56% when the temperature was over 100 °C. This finding confirmed that the moisture could involve into the complexing reaction of peroxides during lowtemperature oxidation process of coal. The experimental results also indicates that the coal samples with 9.82% and 7.24% moisture content is easily inclined to spontaneous combustion and the indicator of the coal spontaneous combustion varies with the content of the moisture. Copyright © 2015, AIDIC Servizi S.r.l.


Wang S.-R.,Yanshan University | Lai X.-P.,Xi'an University of Science and Technology | Lai X.-P.,Key Laboratory of Western Mine and Hazard Prevention | Shan P.-F.,Xi'an University of Science and Technology | Shan P.-F.,Key Laboratory of Western Mine and Hazard Prevention
Research Journal of Applied Sciences, Engineering and Technology | Year: 2013

In order to achieving safe and efficient exploitation in horizontal section top-coal mechanized caving of steep and thick seams, pre-blasting of top-coal is one of the prerequisites and analysis of crack evolution law is a key method to achieving good pre-splitting effects. Based on investigations of coal seams and mining conditions, theories of fracture mechanics were applied to explain the process of caving cracks and fracture toughness of coal seams in preblasting caving were calculated. The distribution of caving cracks was determined with in-situ borehole-wall real deformation optical monitoring systems. The results showed that the pre-splitting crack could rapidly develop in the direction of borehole center line and form the failure surface along the same direction in the last; the fracture toughness of B3 and B6 coal seams was 0.5616 and 1.1900 MPa.m1/2, respectively. The distribution of caving stress from real monitoring instruments provided a theoretical proof for optimizing the parameters of pre-blasting in top-coal safe mining. © Maxwell Scientific Organization, 2013.


Ma L.,Xi'an University of Science and Technology | Ma L.,Key Laboratory of Western Mine and Hazard Prevention | Wang Z.-P.,Xi'an University of Science and Technology | Wang Z.-P.,Key Laboratory of Western Mine and Hazard Prevention | And 6 more authors.
Procedia Engineering | Year: 2013

In this paper, the geometric model, combustion model and the initial and boundary conditions were determined by the actual long narrow confined space. The variation of the temperature field at different time were studied, the temperature distribution law of long narrow confined space were simulated by detection points, which including the dome temperature variation at different time, and the temperature distribution law in the horizontal and vertical direction, the law of temperature distribution in the three directions were studied when the simulation was 120s. The study provided reference for evacuation and rescuing of long narrow confined space fire under the negative pressure ventilation condition. © 2013 The Authors. Published by Elsevier Ltd.


Deng J.,Xi'an University of Science and Technology | Deng J.,Key Laboratory of Western Mine and Hazard Prevention | Ma L.,Xi'an University of Science and Technology | Ma L.,Key Laboratory of Western Mine and Hazard Prevention | And 7 more authors.
Procedia Engineering | Year: 2013

The critical velocity of tunnel fire of ten groups power from 10 to 100 MW were simulated using FDS. The critical velocities under different fire power were determined. For example 50MW tunnel fire. The inside the tunnel temperature, speed and visibility distribution at Y = 5m under the critical velocity were studied. Through the comparison of the gas average temperature of fire source upstream and downstream, and the average visibility of 0-195m,195-250m, 250-300m, 300-350m, 350-400m. The effects of the critical velocity to rescue and evacuation during tunnel fire were analyzed. The relationship curve between critical velocity and heat release rate was fitted out, and obtained that the simulation curve is closer to the results of Bettis by contrast with the empirical formula of Bettis and Thomas. © 2013 The Authors. Published by Elsevier Ltd.


Chen X.-K.,Xi'an University of Science and Technology | Chen X.-K.,Key Laboratory of Western Mine and Hazard Prevention | Zhu H.-L.,Xi'an University of Science and Technology | Zhu H.-L.,Key Laboratory of Western Mine and Hazard Prevention | Chen J.-Q.,Shenhua Xinjiang Energy Ltd Corporation
Journal of Coal Science and Engineering | Year: 2011

Major mineral hazard identifications should consider perilous types of fatal accidents in collieries from its definition, and then set existent hazardous objects and their relevant amount as referenced factors. Eliminating hazards in systems and decreasing risks are their essential purposes with help of hazard identification, risk evaluation and management. By pre-control on major hazards, fatal accidents are avoided, stuffs' safety and healthy are protected, levels of safe management are enhanced, and perpetual systems are built up finally. However, choosing the proper identification and evaluation is a problem all along. Based on specific condition in Jiangou Coal Mine, method of LEC was applied for hazard identification and evaluation in the pre-blasting process within horizontal section top-coal mechanized caving of steep seams. And control measures to of each hazard were put forward. The identification method combining qualitative and quantitative analysis. So, it is practical and operable for the method to develop the given scientific research and has a distinctive impact on high efficiency and safety products for pre-blasting in horizontal section top-coal mechanized caving of steep seams. © 2011 The Editorial Office of Journal of Coal Science and Engineering (China) and Springer-Verlag Berlin Heidelberg.


Wen H.,University of Science and Technology of China | Wen H.,Key Laboratory of Western Mine and Hazard Prevention | Guo J.,University of Science and Technology of China | Guo J.,Key Laboratory of Western Mine and Hazard Prevention | And 6 more authors.
Advances in Engineering Materials and Applied Mechanics - Proceedings of the 5th International Conference on Machinery, Materials Science and Engineering Applications, MMSE 2015 | Year: 2016

Temperature-programmed experiments were conducted from 20 to 450 °C in order to investigate characteristic parameters of coal spontaneous combustion at various oxidation concentrations (21%, 17%, 9%, 5%, and 3%). The experiments indicated that temperature played dominant role during the spontaneous combustion of coal. Higher temperatures would lead to larger oxidation reaction rates that represented the same trends for different oxidation concentrations. As the temperature rose, the concentrations of CO and CO2released from spontaneous combustion were increased at the beginning and decreased after exceeding the maximums, roughly between 370 and 430 °C. What’s more, hysteresis phenomenon existed with the deduction of oxygen concentrations. So, the temperature would be higher when same CO/CO2outputs were reached. In addition, with the increase of temperature, the production of hydrocarbons increased exponentially. However, after exceeding 370–430 °C, temperatures of C2H4and C2H6were decreased but the temperature of CH4was increased continuously. The experiments also implied that temperature had negligible effect on the output of hydrocarbons at various oxidation concentrations. © 2016 Taylor & Francis Group, London.


Yu X.Y.,University of Science and Technology of China | Wang Q.,Key Laboratory of Western Mine and Hazard Prevention | Zhao B.C.,Key Laboratory of Western Mine and Hazard Prevention | Guo W.B.,University of Science and Technology of China | Wang J.D.,University of Science and Technology of China
Applied Mechanics and Materials | Year: 2014

Through analyzing the structure of the alluvium and bedrocks, a discrimination method of main influence factors of surface subsidence was proposed, and the discrimination formula was put forward. Taking the overburden and ground surface of the large cutting height working face in Bin Chang mining region as the research object, the structure and location of key stratum and the structure of the alluvium was analyzed. Besides, through the surface monitoring, the parameters of ground movement and deformation was given, and the discrimination method was verified to be correct. Furthermore, using numerical simulation, the alluvium and bedrocks influences on the surface subsidence under different mining width were studied respectively; the ground movement and deformation characteristics under the influence of alluvium and bedrocks were put forward. The study has provided a basis for the prediction of surface subsidence under certain conditions. © (2014) Trans Tech Publications, Switzerland.

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