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    Wyświetlanie 1-4 z 4
    Tytuł:
    Determination of stress state in coal seam based on inverse problem solution using acoustic sounding data
    Autorzy:
    Kudaibergenov, Mels K.
    Iskakov, Kazizat T.
    Kudaibergenova, Bakytzhan S.
    Powiązania:
    https://bibliotekanauki.pl/articles/88885.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
    Tematy:
    coal seam
    stress
    elasticity theory
    biharmonic equation
    inverse problem
    Opis:
    The paper presents an algorithm for calculating the horizontal, vertical and tangential stresses in a horizontal coal seam lying between galleries. These stresses are expressed in terms of the Airy function, which satisfies a homogeneous biharmonic equation. For its numerical solution it is necessary to set boundary conditions. Practical limitations do not allow us to determine the tangential stresses on horizontal boundaries of the coal seam. Calculations of stresses are proposed to be carried out in two steps. The first step is to solve the inverse problem for the biharmonic equation to find unknown tangential stresses on horizontal boundaries of the coal seam. The inverse problem is solved by minimizing the residual functional. Its strong convexity is proved, which implies the existence and uniqueness of the solution of the inverse problem. The second step is to solve the boundary value problem for the biharmonic equation to calculate stresses in the coal seam. The result of a numerical experiment is presented.
    Źródło:
    Mining Science; 2019, 26; 173-187
    2300-9586
    2353-5423
    Pojawia się w:
    Mining Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Finite element analysis of load characteristic of shield bolter miner cutting head under complex coal seam condition
    Autorzy:
    Qiao, S.
    Xia, Y. M.
    Liu, Z. Z.
    Liu, J. S.
    Ning, B.
    Wang, A. L.
    Powiązania:
    https://bibliotekanauki.pl/articles/89071.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
    Tematy:
    complex coal seam
    shield bolter miner
    load characteristic
    specific energy
    load fluctuation
    Opis:
    Aiming at the complex conditions of the first shielded bolter miner in the actual work, the mechanical model of bolter miner cutting head was established. Based on cutting mechanism of the conical pick and the cutting head, the cutting head load and torque analysis model under complex coal seam were established. The dynamic characteristics of load and torque in the process of cutting head are analyzed under three different working conditions of cutting roof-coal layers, coal-floor layers and coal seam by finite element method. The results show that when the damage variable D=1, the coal-rock completely lacks the bearing capacity, and it forms arc-shaped crushing groove on the coal-rock. The large difference of torque between roof-coal layers and the roof-coal layers in the conical pick is 112 Nm, which indicates that the cutting head has the best performance with cutting the coal seam first and then cutting the rock. In the process of excavation, the load fluctuation coefficient of cutting the coal-floor layers and roof-coal layers is about 1.2 times of that of the coal seam. The results can provide a reference for the efficient cutting and performance evaluation of the bolter miner.
    Źródło:
    Mining Science; 2017, 24; 85-97
    2300-9586
    2353-5423
    Pojawia się w:
    Mining Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Theoretical analysis of support stability in large dip angle coal seam mined with fully-mechanized top coal caving
    Autorzy:
    Ji, Yucheng
    Zhang, Yinghua
    Huang, Zhian
    Shao, Zhenlu
    Gao, Yukun
    Powiązania:
    https://bibliotekanauki.pl/articles/1402319.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
    Tematy:
    large dip angle
    hydraulic support
    stability
    coal
    Opis:
    Support stability is critical to ensure fully-mechanized top coal caving of large dip angle coal seam. To obtain the relations between each factor and hydraulic support stability, the mechanic model of large dip angle coal seam along face dip and strike was built to analyze support stability, including antitoppling, anti-slip, and anti-rotation of supports. The result indicates: Along the face dip, the suport stability was negatively correlated with dip angle; Higher top caving means lower anti-rotation at suport tail; With initial support force and working resistance of supports enhanced, the anti-slip, and antirotation stability of supports can be risen significantly. Along the strike, the critical toppling angle was proportional to dip angle, mining height, support weight, support width and support force; The critica slip angle was positive correlation with support force, friction coefficient of roof and supports. According to the results of both mechanical analysis and engineering projects, support stability in large dip angle can be risen efficiently and supports slipping, toppling and rotation can be avoided by selecting proper technical methods and equipment, like enhancing initial support force appropriately.
    Źródło:
    Mining Science; 2020, 27; 73-87
    2300-9586
    2353-5423
    Pojawia się w:
    Mining Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study of the impact of exploitation structures on pressure distribution and adsorbed methane content in coal seams using dynamic flow models. A case study
    Autorzy:
    Szott, Wiesław
    Miłek, Krzysztof
    Łętkowski, Piotr
    Gołąbek, Andrzej
    Powiązania:
    https://bibliotekanauki.pl/articles/1402316.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
    Tematy:
    methane drainage
    coal seam
    exploitation structures
    desorption
    reservoir simulation
    Opis:
    One of the most serious difficulties encountered during the estimation of results of various methods of methane drainage from coal seams is the determination of the initial condition of the analysed coal seam prior to commencement of the actual process of methane drainage. It is well known that the exploitation operation in adjacent coal seams, as well as preparatory works in the analysed seam may significantly modify the original state of methane adsorption in that seam, as well as influence the distribution of pore pressure and saturation of its natural fractures with fluids (gas, water). This state is of dynamic nature and depends on a long and complex history of the mining activity in the analysed facility and its surrounding. Detailed specification of the above condition is usually replaced by qualitative and very approximate models, which does not allow for consideration of the process preceding the methane drainage. The subject of the paper is the quantitative evaluation of the initial conditions for a coal seam with the use of dedicated simulation models of the analysed seam along with its broad surroundings. Results of this modelling including modifications of appropriate transport parameters of layers between the seams and their influence on detailed distribution of pore pressures, levels of methane desorption from the coal matrix, directions of reservoir fluids flow (methane, water) and saturation with these fluids in natural fractures of the selected seam, as well as in the pores of overburden and underburden rocks will be thoroughly analysed for determination of spacious and temporal effects of the mining activities in terms of their influence on the selected seam.
    Źródło:
    Mining Science; 2020, 27; 133-153
    2300-9586
    2353-5423
    Pojawia się w:
    Mining Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-4 z 4

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