scholarly journals Study on the Mechanical Relationship among the Backfilling Mining Support, Roof Rock Beam, and Gangue Filling Body in Comprehensive Mechanized Filling Mining Process

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Zhimin Huang ◽  
Lei Zhang ◽  
Zhanguo Ma
Keyword(s):  
Mechanical Model ◽  
Roof Rock ◽  
Hydraulic Support ◽  
Simulation Experiments ◽  
Filling Height ◽  
Calculation Results ◽  
And Migration ◽  
Elastic Foundation Beam ◽  
Rock Beam ◽  
Similar Simulation

Based on the theory of elastic foundation beam, the mechanical model of the backfilling mining support-roof rock beam-gangue filling body under the condition of comprehensive mechanized filling mining is established. The foundation coefficient of each part is determined, and the subsidence of each part of roof rock beam is calculated. It is found that the initial filling height is the decisive factor to control the subsidence and migration stability of each part of the roof rock beam. Properly increasing the pushing force of backfilling-coal mining hydraulic support on the filling body can also effectively control the roof subsidence. The comprehensive mechanized filling mining process was studied by similar simulation experiments, it is found that the influence law of initial filling height on roof rock beam subsidence is the same as that of theoretical analysis, and the experimental measurement values and fitting function relationships are consistent with the theoretical calculation results.

Rock Floor Pressure Analysis of Hydraulic Support

2013 ◽  
Vol 389 ◽  
pp. 1058-1061
Author(s):  
Zhi Wang ◽  
He Ping Ni
Keyword(s):  
Pressure Distribution ◽  
Hard Rock ◽  
Beam Theory ◽  
Base Plate ◽  
Maximum Pressure ◽  
Distribution Law ◽  
Hydraulic Support ◽  
Calculation Results ◽  
Elastic Foundation Beam ◽  
Selection Of

According to the plastic floor assumptions, the floor pressure distribution law was obtained based on plane force analysis of hydraulic support. In order to compare the floor pressure on the elastic floor and plastic floor, Elastic foundation beam theory was introduced to the calculation of the floor pressure. The results show that the pressure distribution is changed with the changing of the subgrade coefficient. The pressure is trapezoidal distributed when the floor is relatively soft and the plastic floor assumptions is reasonable. In a relatively hard rock floor, the maximum pressure appear near the column nest which is very different from the calculation results based on the plastic base plate assumptions. It is suggested that the soft and the hard rock floor should be treated differently during the design and selection of hydraulic support. .

scholarly journals Mechanical Modeling of Roof Fracture Instability Mechanism and Its Control in Top-Coal Caving Mining under Thin Topsoil of Shallow Coal Seam

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Peilin Gong ◽  
Tong Zhao ◽  
Kaan Yetilmezsoy ◽  
Kang Yi
Keyword(s):  
Coal Seam ◽  
Mechanical Model ◽  
Main Roof ◽  
Stability Control ◽  
Hydraulic Support ◽  
Rock Stability ◽  
Shallow Coal Seam ◽  
Minimum Height ◽  
The Stability ◽  
Working Resistance

This study aimed to explore the safe and efficient top-coal caving mining under thin topsoil of shallow coal seam (SCS) and realize the optimization of hydraulic support. Numerical simulation and theoretical analysis were used to reveal the stress distribution of the topsoil, the structure characteristics of the main roof blocks, and the development of the roof subsidence convergence. Step subsidence of the initial fractured main roof after sliding destabilization frequently existed, which seriously threatened the safety of the hydraulic supports. Hence, a mechanical model of the main roof blocks, where the topsoil thickness was less than the minimum height of the unloading arch, was established, and the mechanical criterion of the stability was achieved. The working resistance of the hydraulic support was calculated, and the reasonable type was optimized so as to avoid crushing accident. Findings of the present analysis indicated that the hydraulic support optimization was mainly affected by fractured main roof blocks during the first weighting. According to the block stability mechanical model based on Mohr–Coulomb criterion, the required working resistance and the supporting intensity were determined as 4899 kN and 0.58 MPa, respectively. The ZZF5200/19/32S low-position top-coal caving hydraulic support was selected for the studied mine and support-surrounding rock stability control of thin-topsoil SCS could be achieved without crushing accident.

Diffusion of Radionuclides in Compacted Bentonite : Results from Combined Glass Dissolution and Migration Tests

1994 ◽  
Vol 353 ◽  
Author(s):  
Masaki Tsukamoto ◽  
T. Ohe ◽  
T. Fujita ◽  
R. HesbÖl ◽  
H-P. Hermansson
Keyword(s):  
Dry Density ◽  
Apparent Diffusion Coefficients ◽  
Glass Dissolution ◽  
Glass Corrosion ◽  
Gas Atmosphere ◽  
Apparent Diffusion ◽  
Calculation Results ◽  
The Difference ◽  
And Migration ◽  
Elemental Mass

AbstractDiffusion experiments of radionuclides in compacted sodium bentonite with a dry density of 1.0 g/cm3 were performed in nitrogen gas atmosphere at 90 °C for 208 d and 375 d. The corrosion experiments of crushed radioactive glass, JSS-A, carried out simultaneously to provide the source of the radionuclides for the diffusion experiments. The normalized elemental mass losses of cesium isotopes and 238Pu were lower than those of boron (ca. 10 g/m2) probably because of the difference of sorption and/or precipitation. The apparent diffusion coefficients of 238Pu, 234U and 125Sb were determined to be 2x 10-14 m2/s, 5x 10-12 m2/s and 2x 10-12 m2/s, respectively. The distribution coefficient of Pu estimated from the diffusion data was of the same order as that from batch sorption experiments. The glass corrosion and the plutonium diffusion were described by the geochemical codes PHREEQE, STRAG4 and GESPER. The calculation results well fitted the observed data.

Design and Simulation of Fully Mechanized Hydraulic Support

2014 ◽  
Vol 644-650 ◽  
pp. 199-202
Author(s):  
Pei Qin Wang ◽  
Zeng Shun Xu ◽  
Zuo Feng Sun ◽  
Hui Yuan Jiang
Keyword(s):  
Mechanical Properties ◽  
Mathematical Model ◽  
Mechanical Model ◽  
Simulation Analysis ◽  
Virtual Prototype ◽  
Dynamics Simulation ◽  
Prototype Model ◽  
Design Calculation ◽  
Hydraulic Support ◽  
Element Analysis

Based on theoretical calculation, virtual prototype technology and the method of finite element analysis, the fully mechanized hydraulic support is designed and simulated. Firstly, the four-link mechanism of hydraulic support mechanical model and mathematical model are established, the demission is confirmed by design calculation of structure. Secondly, through the establishment of rigid parameterized virtual prototype model of the system, dynamics simulation analysis and research is finished based on ADAMS on the mechanical properties. Finally, based on FEA, the modal calculation of key components is completed by using ANSYS.

Theoretical Evaluation of Oxidation Rate of Zr

2013 ◽  
Vol 1535 ◽  
Author(s):  
Yasunori Yamamoto ◽  
Kazunori Morishita ◽  
Hirotomo Iwakiri ◽  
Yasunori Kaneta
Keyword(s):  
Oxygen Vacancy ◽  
Diffusion Process ◽  
Oxidation Rate ◽  
Experimental Fact ◽  
Stress Effect ◽  
Theoretical Evaluation ◽  
Simple Diffusion ◽  
Calculation Results ◽  
And Migration ◽  
Diffusion Coefficient Of Oxygen

ABSTRACTFirst principle calculations were performed to evaluate stress effect on the diffusion process of oxygen vacancy in ZrO2 film, and oxidation rate of Zr was evaluated by solving simple diffusion equations. Our calculation results have indicated that both the vacancy formation and migration energies of ZrO2 increase with increasing compressive applied stress. The energy increase causes a decrease in the diffusion coefficient of oxygen vacancy in ZrO2, leading to a decrease in oxidation rate of Zr. The stress effect on diffusion process may explain the experimental fact that Zr is oxidized in proportion to the cubic root of time.

Drag Force Analysis of Spheres Penetrating Gelatin Based on Surface Integral

2011 ◽  
Vol 105-107 ◽  
pp. 561-565
Author(s):  
Gen Lin Mo ◽  
Zhi Lin Wu ◽  
Kun Liu
Keyword(s):  
Frictional Force ◽  
Mechanical Model ◽  
High Speed ◽  
Dynamic Force ◽  
Force Analysis ◽  
Surface Integral ◽  
Area Element ◽  
Position Data ◽  
Calculation Results ◽  
Wetted Area

A new method based on surface integral is presented in the research of mechanical mechanism of spheres penetrating gelatin. On the assumption that each wetted area element is applied with dynamic force perpendicular to the surface, frictional force parallel to the surface and material resistance which is a constant, the resultant force applied on spheres was integrated containing three unknown coefficients. Transparent gelatin was used in the experiments and steel spheres were fired at speed around 800m/s. High speed cameras got the position data of the penetrating spheres. The uncertain coefficients in the movement equations were determined with these data. The equations were solved in analytical forms. Experiments show that the coefficients are constant for spheres with different radiuses. Calculation results demonstrate that the mechanical model is good to predict the movement of spheres in gelatin.

Researches on the Ring Stiffness Condition in Cold Ring Rolling

2011 ◽  
Vol 291-294 ◽  
pp. 297-305
Author(s):  
Li Bo Pan ◽  
Lin Hua ◽  
Dong Sheng Qian
Keyword(s):  
Mechanical Model ◽  
Position Angle ◽  
Rolling Process ◽  
Ring Rolling ◽  
Advanced Manufacturing Technology ◽  
Advanced Manufacturing ◽  
Simulation Experiments ◽  
Element Simulation ◽  
Cold Ring Rolling ◽  
Ring Blank

Cold ring rolling is a kind of advanced manufacturing technology. During rolling process the ring may be collapsed or deformed unexpectedly under the pressure of guide roll because the stiffness condition is not met. The force of guide roll to ring was obtained by analyzing the forces to ring. The stiffness condition expressions of ring during rolling were shown after constructing the mechanical model. According to the expressions, the effects of several parameters on the stiffness condition were discussed and analyzed in detail, such as position angle of guide roll, friction coefficient and feed rate, etc, which revealed essential reasons of some cases occurring in cold ring rolling. Then the ring blank dimension was deduced based on the ring stiffness condition. The dimensions of ring blank should meet a relationship to ensure the ring stiffness condition to be satisfied during rolling, which can conduct the practical manufacturing effectively. Finally the analysis and effect laws were proved by finite element simulation experiments. The researches could be helpful to control parameter in cold ring rolling effectively for high quality products.

Design of Shield Hydraulic Support with Variable Parameters

2011 ◽  
Vol 121-126 ◽  
pp. 1411-1415 ◽  
Author(s):  
Xi Jing Zhao ◽  
Jun Min Lu ◽  
Rui Luo
Keyword(s):  
Research And Development ◽  
Mechanical Model ◽  
Mechanical Modeling ◽  
Hydraulic Support ◽  
Development Environment ◽  
Support Design ◽  
Variable Parameters ◽  
Development Platform ◽  
Software Development Environment ◽  
Set Up

This paper builds the design platform for the shield hydraulic support with variable parameters.The platform characterizes the following aspects: support’s mechanical modeling, the whole and parts designing,strength checking. With the aid of VC++ software development environment, the mechanical model with variable parameters is set up and the support design is carried on,including design and check of the whole support and its components,such as top beam,shielding beam,the baseboard and so on. The development of this software could shorten the research and development periods of supports with similar structures and provide the research and development platform for the support design.

scholarly journals Study on Overburden Stability and Development Height of Water Flowing Fractured Zone in Roadway Mining with Cemented Backfill

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yu Dong ◽  
Yucheng Huang ◽  
Jifang Du ◽  
Fei Zhao
Keyword(s):  
Empirical Formula ◽  
Mechanical Model ◽  
Fractured Rock ◽  
Coal Pillar ◽  
Main Roof ◽  
Mechanical Analysis ◽  
Overburden Rock ◽  
Fractured Zone ◽  
The Stability ◽  
Rock Beam

In order to explore the stability of overburden rock and the development height of water flowing fractured zone in roadway filling mining, based on the movement and deformation mechanism of overburden rock, the mechanical analysis of overburden stability and failure was carried out, and the mechanical model of main roof rock beam was established, and the ultimate span and limit deflection of rock beam fracture were deduced. Combined with the mechanical model of the main roof fractured rock, the basis for the judgment of overburden failure developing to fractured zone is given in this paper. Taking a coal mine roadway backfill under water-bearing stratum as an example, based on the equivalent mining height, the theoretical calculation and analysis are carried out on the stability of overburden rock and the height of water flowing fractured zone. The reliability of the theoretical analysis is verified compared with the empirical formula and the numerical simulation results. The results showed that the water flowing fractured zone developed to the bottom of no. 7 glutenite, with a height of 32.5 m, slightly less than the calculation result of the empirical formula. The thickness of the waterproof coal pillar was 39.8 m, which was much less than the distance from the aquifer to the coal seam and can be mined safely.

scholarly journals Floor failure depth of upper coal seam during close coal seams mining and its novel detection method

2017 ◽  
Vol 36 (5) ◽  
pp. 1265-1278 ◽  
Author(s):  
Wei Zhang ◽  
Dongsheng Zhang ◽  
Dahong Qi ◽  
Wenmin Hu ◽  
Ziming He ◽  
...  
Keyword(s):  
Stress Distribution ◽  
Coal Seam ◽  
Mechanical Model ◽  
Coal Pillar ◽  
Coal Seams ◽  
Geological Conditions ◽  
Floor Failure ◽  
Calculation Results ◽  
Failure Depth ◽  
Close Coal Seams

The primary problem needed to be solved in mining close coal seams is to understand quantitatively the floor failure depth of the upper coal seam. In this study, according to the mining and geological conditions of close coal seams (#10 and #11 coal seams) in the Second Mining Zone of Caocun Coal Mine, the mechanical model of floor failure of the upper coal seam was built. Calculation results show that the advanced abutment pressure caused by the mining of the upper coal seam, resulted in the floor failure depth with a maximum of 26.1 m, which is 2.8 times of the distance between two coal seams. On this basis, the mechanical model of the remaining protective coal pillar was established and the stress distribution status under the remaining protective coal pillar in the 10# coal seam was then theoretically analysed. Analysis results show that stress distribution under the remaining protective coal pillar was significantly heterogeneous. It was also determined that the interior staggering distance should be at least 4.6 m to arrange the gateways of the #209 island coalface in the lower coal seam. Taken into account a certain safety coefficient (1.6–1.7), as well as reducing the loss of coal resources, the reasonable interior staggering distance was finally determined as 7.5 m. Finally, a novel method using radon was initially proposed to detect the floor failure depth of the upper coal seam in mining close coal seams, which could overcome deficiencies of current research methods.

Sign in / Sign up

Export Citation Format

Share Document