scholarly journals Influence of Roadway Cross-Section Shape on Gas Explosion Shock Wave Law in U-Type Ventilation Working Faces

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Jiajia Liu ◽  
Mengqi Shen ◽  
Shouqi Chen ◽  
Ming Yang
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Simulation Study ◽  
Simulation Software ◽  
Effective Length ◽  
Shaanxi Province ◽  
Gas Explosion ◽  
Cross Sectional ◽  
Working Face ◽  
Tunnel Section

In U-shaped ventilation working face, different tunnel section shapes are one of the important factors affecting the propagation of gas explosion shock wave. In order to study the propagation law of gas explosion shock wave in working face, the numerical simulation study was carried out by using Fluent simulation software combined with the actual situation of gas explosion in #415 working face of Chenjiashan Coal Mine in Shaanxi Province. By constructing a three-dimensional mathematical and physical model, a simulation study of the upper-corner gas explosion was carried out. The results are described as follows. (1) After the gas explosion shock wave propagates 40 m, the overpressure peak equidistant difference tends to be stable and attenuates and propagates in the form of a single shock wave. The study determines that the effective length of the U-shaped ventilation inlet/return tunnel is 40 m. (2) When the tunnel section is trapezoidal, the initial overpressure of the gas explosion shock wave propagating to the inlet/return airway is the highest, followed by rectangular and semicircular arches, but the internal overpressure attenuation trend of different cross-sectional shapes is the same. (3) The gas explosion shock wave propagates radially along the working face section during the working face propagation. The farther away the location is from the upper corner of the tunnel during a gas explosion with different cross-sectional shapes, the closer the cutoff overpressure peak is. The attenuation trend of overpressure with the propagation distance conforms to the power function law. The research results provide an important theoretical direction for the numerical simulation of gas explosions in coal mining faces.

scholarly journals A numerical simulation of realistic top coal caving intervals under different top coal thicknesses in longwall top coal caving working face

2021 ◽  
Author(s):  
Chuang Liu ◽  
Huamin Li
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Distinct Element ◽  
Simulation Models ◽  
Simulation Software ◽  
Thick Coal Seam ◽  
Coal Recovery ◽  
Working Face ◽  
Longwall Top Coal Caving ◽  
Selection Of

Abstract In the process of longwall top coal caving, the selection of the top coal caving interval along the advancing direction of the working face has an important effect on the top coal recovery. To explore a realistic top coal caving interval of the longwall top coal caving working face, longwall top coal caving panel 8202 in the Tongxin Coal Mine is used as an example, and 30 numerical simulation models are established by using Continuum-based Distinct Element Method (CDEM) simulation software to study the top coal recovery with 4.0 m, 8.0 m, 12.0 m, 16.0 m, 20.0 m and 24.0 m top coal thicknesses and 0.8 m, 1.0 m, 1.2 m, 1.6 m and 2.4 m top coal caving intervals. The results show that with an increase in the top coal caving interval, the single top coal caving amount increases. The top coal recovery is the highest with a 0.8 m top coal caving interval when the thickness of the top coal is less than 4.0 m, and it is the highest with a 1.2 m top coal caving interval when the coal seam thickness is greater than 4.0 m. These results provide a reference for the selection of a realistic top coal caving interval in thick coal seam caving mining.

scholarly journals Control of Gob-Side Roadway with Large Mining Height in Inclined Thick Coal Seam: A Case Study

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xie Fuxing
Keyword(s):  
Numerical Simulation ◽  
Coal Pillar ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Mine Pressure ◽  
Thick Coal Seam ◽  
Working Face ◽  
Rock Structure ◽  
Large Mining Height ◽  
Mining Height

The gob-side roadway of 130205, a large-mining-height working face in the Yangchangwan coal mine, was investigated in terms of the mine pressure law and support technology for large mining heights and narrow coal pillars for mining roadways. The research included field investigations, theoretical analysis, numerical simulation, field tests, and other methods. This paper analyzes the form of movement for overlying rock structure in a gob-side entry with a large mining height and summarizes the stress state and deformation failure characteristics of the surrounding rock. The failure mechanism of the surrounding rock of the gob-side roadway and controllable engineering factors causing deformation were analyzed. FLAC3D numerical simulation software was used to explore the influence law of coal pillar width, working face mining height, and mining intensity on the stability of the surrounding rock of the gob-side roadway. Ensuring the integrity of the coal pillar, improving the coordination of the system, and using asymmetric support structures as the core support concept are proposed. A reasonably designed support scheme for the gob-side roadway of the working face for 130205 was conducted, and a desirable engineering effect was obtained through field practice verification.

scholarly journals The Influences of Key Strata Compound Breakage on the Overlying Strata Movement and Strata Pressure Behavior in Fully Mechanized Caving Mining of Shallow and Extremely Thick Seams: A Case Study

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Junmeng Li ◽  
Yanli Huang ◽  
Jixiong Zhang ◽  
Meng Li ◽  
Ming Qiao ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Abutment Pressure ◽  
Simulation Software ◽  
Strata Movement ◽  
Key Strata ◽  
Pressure Behavior ◽  
Ground Pressure ◽  
Working Face ◽  
Overlying Strata Movement ◽  
Overlying Strata

In order to analyze the impact of compound breakage of key strata on overlying strata movement and strata pressure behavior during the fully mechanized caving mining in shallow and extremely thick seams, this paper took the 1322 fully mechanized caving face in Jindi Coal Mine in Xing County as the engineering background. Under the special mining and geological condition mentioned above, UDEC numerical simulation software was applied to research the engineering problems, and results of numerical simulation were verified through the in-site measurement. The research results showed that during the fully mechanized caving mining in shallow and extremely thick seams, the inferior key strata affected by mining movement behaved in the mode of sliding instability and could not form the stable structure of the voussoir beam after breaking and caving. In addition, the main key strata behaved in the mode of rotary instability, and the caving rocks behind the goaf were gradually compacted because of the periodic instability of the main key strata. With the continuous advance of the working face, the abutment pressure of the working face was affected by the compound breakage and periodic instability of both the inferior key strata and the main key strata, and the peaks of the abutment pressure presented small-big-small-big periodical change characteristics. Meanwhile, the risk of rib spalling ahead of the working face presented different levels of acute or slowing trends. The actual measurement results of ground pressure in the working face showed that, in the working process, the first weighting interval of the inferior key strata was about 51 m and its average periodic weighting interval was about 12.6 m, both of which were basically consistent with the results of numerical simulation. The research has great significance in providing theoretical guidance and practical experience for predicting and controlling the ground pressure under the similar mining and geological conditions.

scholarly journals Numerical Investigation of Rockburst Effect of Shock Wave on Underground Roadway

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Cai-Ping Lu ◽  
Guang-Jian Liu ◽  
Hong-Yu Wang ◽  
Jun-Hua Xue
Keyword(s):  
Shock Wave ◽  
Simulation Software ◽  
Vibration Source ◽  
Whole Process ◽  
Working Face ◽  
Mining Conditions ◽  
Coal Rock ◽  
Mining Coal ◽  
And Control ◽  
Attenuation Characteristics

Using UDEC discrete element numerical simulation software and a cosine wave as vibration source, the whole process of rockburst failure and the propagation and attenuation characteristics of shock wave in coal-rock medium were investigated in detail based on the geological and mining conditions of 1111(1) working face at Zhuji coal mine. Simultaneously, by changing the thickness and strength of immediate roof overlying the mining coal seam, the whole process of rockburst failure of roadway and the attenuation properties of shock wave were understood clearly. The presented conclusions can provide some important references to prevent and control rockburst hazards triggered by shock wave interferences in deep coal mines.

scholarly journals Numerical simulation of realistic top coal caving intervals under different top coal thicknesses in longwall top coal caving working face

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chuang Liu ◽  
Huamin Li
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Distinct Element ◽  
Simulation Models ◽  
Simulation Software ◽  
Thick Coal Seam ◽  
Coal Recovery ◽  
Working Face ◽  
Longwall Top Coal Caving ◽  
Selection Of

AbstractIn the process of longwall top coal caving, the selection of the top coal caving interval along the advancing direction of the working face has an important effect on the top coal recovery. To explore a realistic top coal caving interval of the longwall top coal caving working face, longwall top coal caving panel 8202 in the Tongxin Coal Mine is used as an example, and 30 numerical simulation models are established by using Continuum-based Distinct Element Method simulation software to study the top coal recovery with 4.0 m, 8.0 m, 12.0 m, 16.0 m, 20.0 m and 24.0 m top coal thicknesses and 0.8 m, 1.0 m, 1.2 m, 1.6 m and 2.4 m top coal caving intervals. The results show that with an increase in the top coal caving interval, the single top coal caving amount increases. The top coal recovery is the highest with a 0.8 m top coal caving interval when the thickness of the top coal is 4.0 m, and it is the highest with a 1.2 m top coal caving interval when the coal seam thickness is greater than 4.0 m. These results provide a reference for the selection of a realistic top coal caving interval in thick coal seam caving mining.

The Thermal-Fluent-Solid Coupling Numerical Simulation Study of Coal and Rock Containing Gas

2014 ◽  
Vol 1010-1012 ◽  
pp. 1498-1501
Author(s):  
Tao Qin ◽  
Yong Li Liu ◽  
Kai Yun Zhang
Keyword(s):  
Numerical Simulation ◽  
Temperature Change ◽  
Simulation Study ◽  
Viscosity Coefficient ◽  
Gas Pressure ◽  
Seepage Velocity ◽  
Gas Concentration ◽  
Working Face ◽  
Gas Seepage ◽  
The Face

COMSOL software was used in the paper for numerical simulation of excavation face and study stress, gas pressure, the gas seepage velocity, displacement and the change of temperature as well as to the effect of dynamic disaster under different temperature conditions. The results show that the speed of gas pressure to reduce slowed, the gas pressure near the working face gradient increasing with the increase of temperature; the face gas concentration changed not significantly because of the change of temperature under the condition of the temperature change is not big; seepage velocity varies was not obvious under the condition of other conditions don't change, because the viscosity coefficient of the change was not obvious.

Simulation Study of the Matsukawa Geothermal Reservoir: Natural State and Its Response to Exploitation

1992 ◽  
Vol 114 (4) ◽  
pp. 309-314 ◽  
Author(s):  
M. Hanano
Keyword(s):  
Numerical Simulation ◽  
Simulation Study ◽  
Geothermal Reservoir ◽  
Natural State ◽  
Two Dimensional ◽  
Cross Sectional ◽  
Sectional Model ◽  
Shallow Part

A numerical simulation study on the natural state of the Matsukawa, Japan geothermal reservoir was carried out with a simplified two-dimensional cross-sectional model. The results agreed reasonably well with the observed data and showed that there was a thin vapor-dominated zone at the shallow part of the reservoir. The results clearly indicate that the ideas on the natural state of the Matsukawa geothermal reservoir presented by Hanano and Matsuo (1990) are feasible.

scholarly journals Analysis of the Characteristics and Influencing Factors of Gas Explosion in Heading Face

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Xue-bo Zhang ◽  
Jian-liang Gao ◽  
Jing-zhang Ren ◽  
Chun-xia Wang
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Influencing Factors ◽  
Geometric Model ◽  
Great Influence ◽  
Ignition Energy ◽  
Gas Explosion ◽  
Step Size ◽  
Time Step ◽  
Time Space

In order to accurately grasp the characteristics and influencing factors of gas explosion in heading face, the mathematical model of gas explosion was determined. According to the actual size of a heading face of a coal mine, a 3D geometric model with a length of 100 m was established, and the effects of ignition energy and gas explosion equivalent on the gas explosion characteristics of the heading face were analyzed. The results show the following. (1) The mathematical models for numerical simulation of gas explosion can accurately simulate the gas explosion and its propagation process. The time-space step size has a great influence on the simulation results. The grid spacing for numerical simulation of mine gas explosion is determined to be 0.1 m and the time step length is determined to be 0.001 s. (2) The ignition energy has a limited effect on gas explosion characteristics. It only has a certain influence on the gas explosion process, but has little influence on the overpressure of shock wave. The larger the ignition energy is, the faster the explosion reaction speed is, and the maximum overpressure increases slightly. When the ignition energy increases to a certain value, the time of peak shock wave and the maximum overpressure both tend to be stable. The ignition energy has little effect on gas explosion characteristics when an explosion accident occurs underground with a large amount of gas accumulation. (3) The gas explosion equivalent has a great influence on the overpressure of gas explosion shock wave. The higher the explosion equivalent is, the greater the pressure is, and the peak value of the shock wave overpressure increases with the explosion equivalent as a power function. The research results have important guiding significance for the research and development of new technology for prevention and control of gas explosion.

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