A numerical simulation on mining pressure law of mechanized mining face in Chang Gou yu Mine

2011 ◽  
Author(s):  
Haiyang Yu ◽  
Binjie Huo ◽  
Xianfa Cui ◽  
Fengzi Jiang
Keyword(s):  
Numerical Simulation ◽  
Mining Face ◽  
Mining Pressure

scholarly journals Support design of main retracement passage in fully mechanised coal mining face based on numerical simulation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yalong Li ◽  
Mohanad Ahmed Almalki ◽  
Cheng Li
Keyword(s):  
Numerical Simulation ◽  
Coal Mine ◽  
Surrounding Rock ◽  
Control Measures ◽  
Coal Face ◽  
Support Design ◽  
Working Face ◽  
Surrounding Rock Control ◽  
Mining Face ◽  
Mining Pressure

Abstract For the comprehensive mechanised coal mining technology, the support design of the main withdrawal passage in the working face is an important link to achieve high yield and efficiency. Due to the impact of mining, the roof movement of the withdrawal passage is obvious, the displacement of the coal body will increase significantly, and it is easy to cause roof caving and serious lamination problems, and even lead to collapse accidents, which will affect the normal production of the mine. In this paper, the mining pressure development law of the main withdrawal passage support under the influence of dynamic pressure is designed, the most favourable roof failure form of the withdrawal passage is determined, and the action mechanism and applicable conditions of different mining pressure control measures are studied. The pressure appearance and stress distribution in the final mining stage of fully mechanised coal face are studied by numerical simulation. The deformation and failure characteristics and control measures of roof overburden in the last mining stage of fully mechanised coal face are analysed theoretically. Due to the fact that periodic pressure should be avoided as far as possible after the full-mechanised mining face is connected with the retracement passage, some auxiliary measures such as mining height control and forced roof blasting are put forward on this basis. The relative parameters of the main supporting forms are calculated. The main retracement of a fully mechanised working face in a coal mine channel is put forward to spread the surrounding rock grouting reinforcement, reinforcing roof, and help support and improve the bolt anchoring force, the main design retracement retracement channels in the channel near the return air along the trough for supporting reinforcing surrounding rock control optimisation measures, such as through the numerical simulation analysis, the optimisation measures for coal mine fully mechanised working face of surrounding rock is feasible. Numerical simulation results also show that the surrounding rock control of fully mechanised working face of coal mine design improvements, its main retreat channel under the roof subsidence, cribbing shrank significantly lower, and closer, to better control the deformation of surrounding rock, achieved significant effect, to ensure the safety of coal mine main retracement channel of fully mechanised working face support.

scholarly journals Analysis of the Influence Characteristics of the Support Stability of a Fully Mechanized Coal Mining Face under the Hard Roof Mining Pressure

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jiaxin Dang ◽  
Min Tu ◽  
Xiangyang Zhang ◽  
Qingwei Bu
Keyword(s):  
Numerical Simulation ◽  
Load Bearing ◽  
Hard Roof ◽  
Working Face ◽  
Cantilever Length ◽  
Mining Face ◽  
Mining Pressure ◽  
Group B ◽  
Coal Reserves ◽  
Two Sides

The conditions of the hard roof in my country vary greatly, ranging from a few meters to tens of meters or even hundreds of meters in thickness. The coal reserves under the hard roof account for about one-third of the total reserves. At present, nearly 40% of fully mechanized mining faces that belong to the hard roof working face has the problem of mining in the hard roof working face. This has a serious impact on the load-bearing stability of the fully mechanized support, and it is urgent to solve the problem of strong underground pressure dynamic disaster under the condition of the hard roof. Based on the research background of 11129 working face in Zhangji Coal Mine in Huainan, this paper constructs a mechanical model of the interaction between the cantilever beam of the hard roof of the stope and the support and then the force distribution equation of the bearing capacity of the supports at different positions of the roof during the periodical rotation of the working face is obtained, which is combined with numerical simulation and engineering site to verify. The research results show that the bearing stability of the support is significantly affected by factors such as the buried depth H, the roof elastic modulus E, the roof thickness h, and the roof cantilever length l0, but most of the influencing factors belong to the geological occurrence conditions of the coal seam itself. Presplit blasting of the roof in advance can effectively destroy the integrity of the roof itself and reduce the periodic breaking distance, thereby improving the apparent environment of roof rock pressure and reducing the force on the working face support. According to the specific geological environment of the 11129 working face, the cutting plan of the cut hole is given out, along the groove 0∼200 and 200∼700 m of the concrete presplitting blasting. The stent force of the top-cutting section fluctuates in the range of 3360.8–4347.9 kN in the range of control top distance (5275∼6175 mm). The load-bearing pressure of the stent before top-cutting is about 1.8 times of that after top-cutting. The pressure distribution of the hydraulic support in the numerical simulation stope is approximately “Λ” in the middle and the low on the two sides. The simulated value is slightly smaller than the theoretical calculation value. The reason is that the goaf is backfilled during the simulation process, and the roof has a certain ability to bear the load. Real-time understanding of the “roof-support” mechanical relationship can effectively ensure the safe and efficient mining of the 11129 working face and also provide experience for the subsequent mining of group B coal in the later period.

scholarly journals Experimental Research and Numerical Simulation of Ejector Precipitator in a Fully Mechanized Mining Face

2020 ◽  
Vol 45 (11) ◽  
pp. 9815-9833
Author(s):  
Guodong Zhai ◽  
Wentao Zhang ◽  
Yaozong Li ◽  
Xinghao Lu ◽  
Wenyuan Hu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Negative Pressure ◽  
Coal Dust ◽  
Structural Parameters ◽  
Dust Concentration ◽  
Dust Removal ◽  
Measuring Point ◽  
Mining Face ◽  
Supply Water

AbstractIn order to effectively reduce the coal dust concentration in a fully mechanized mining face, this research used laboratory experiment, numerical simulation, and field test to conduct an in-depth exploration of the ejector precipitator installed at the low-level caving coal hydraulic support. Firstly, through the experimental platform in the laboratory, the dust removal effect of the nozzle with different structural parameters was tested, and the 3D particle dynamic analyzer was adopted to verify its atomization characteristics; then, the structural parameters corresponding to the nozzle in the best test results were obtained. Secondly, by using Fluent, the negative pressure flow field in the ejector barrel was numerically simulated. The results indicated that when the pressure of supply water was 12 MPa, the negative pressure value formed in the flow field was the lowest and the inspiratory velocity was the largest, which was conducive to dust removal. Finally, the tests of liquid–gas ratio and dust removal ratio were carried out in a fully mechanized mining face. The results showed that when the nozzle specification recommended by the experiment and the pressure of supply water recommended by the numerical simulation were used, the removal ratios of the total coal dust and the respirable coal dust were 89.5% and 91.0%, respectively, at the measuring point of the highest coal dust concentration. It indicates that the ejector precipitator has a good application effect in reducing the coal dust concentration in a fully mechanized mining face and improving the work environment of coal mine workers.

scholarly journals Determination of Reasonable Width of Filling Body for Gob-Side Entry Retaining in Mining Face With Large Cutting Height

2021 ◽  
Author(s):  
Shijiang Pu ◽  
Gui yi Wu ◽  
Qinzhi Liu ◽  
Yuliang Wang ◽  
Qiang Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Mechanical Model ◽  
Vertical Displacement ◽  
Vertical Stress ◽  
Body Width ◽  
Minimum Width ◽  
Mining Face ◽  
The Stability ◽  
Cutting Height ◽  
Two Sides

Abstract When gob-side entry retaining is adopted in mining face with large cutting height, due to large stope space, strong dynamic pressure and other reasons, the filling body is usually broken and unstable due to improper width of filling body, and the stability of surrounding rock of roadway is poor. Therefore, this paper will take Shaqu mine as the engineering background to study the reasonable filling body width of gob-side entry retaining in mining face with large cutting height. Firstly, the stability factors of gob-side entry retaining in mining face with large cutting height are analyzed, and the mechanical model of bearing structure of gob-side entry retaining is established based on the lateral pressure and overlying load of filling body, and the reasonable width of filling body is obtained quantitatively; Numerical simulation is used to analyze the evolution of vertical stress, vertical displacement and plastic zone of working face with the change of filling body width. Finally, combined with the deformation observation results of 24207 gob-side entry retaining roof, two sides and filling body, the rationality of filling body width is verified. The results show that: the setting of the width and strength of the filling body plays an important role in the stability of gob-side entry retaining. According to the mechanical model, the minimum width of the filling body is 2.2m in the lateral direction and 3.9m in the vertical direction; Numerical simulation shows that when the width of filling body is too small, with the increase of filling body width, the vertical stress of filling body increases gradually. When the width of filling body reaches a certain value, the vertical stress decreases with the increase of width, and the stress concentration area will change from symmetrical type to eccentric load type, from the middle of filling body to the side of filling body near gob. If the width of the filling body is too small, the filling body will be too broken to bear the load, resulting in too small vertical stress and too large vertical displacement of the roadway roof. The larger the width of the filling body is, the greater the cutting resistance is, the more timely the side roof of the gob can be cut off, the less the stress of the roadway and the filling body, and the more stable the retained roadway is. Finally, through the observation of 24207 gob-side entry retaining, the total deformation of two sides and roof and floor of roadway tends to be stable after 665mm and 597mm respectively. The roof of roadway does not appear severe subsidence and obvious cracking, and the floor does not appear too large floor heave. The effect of roadway retaining is good, which indicates that 4m support can meet the needs of practical engineering.

scholarly journals Numerical Simulation of Coal Wall Cutting and Lump Coal Formation in a Fully Mechanized Mining Face

2020 ◽  
Author(s):  
Yong Yuan ◽  
Shengzhi Wang ◽  
Wenmiao Wang ◽  
Cheng Zhu
Keyword(s):  
Numerical Simulation ◽  
Cutting Force ◽  
Cutting Process ◽  
Working Face ◽  
Secondary Damage ◽  
Coal Wall ◽  
Statistical Analysis Method ◽  
Mining Face ◽  
Lump Coal ◽  
Cutting Model

Abstract It is difficult to accurately calculate the lump coal rate in a fully mechanized mining face. Therefore, a numerical simulation of the coal wall cutting process, which revealed the crack expansion, development, evolution in the coal body and the corresponding lump coal formation mechanism, was performed in PFC. Moreover, a correlation was established between the cutting force and lump coal formation, and a statistical analysis method was proposed to determine the lump coal rate. The following conclusions were drawn from the results. (1) Based on a soft ball model, a coal wall cutting model was established. By setting the roller parameters based on linear bonding and simulating the roller cutting process of the coal body, the coal wall cutting process was effectively simulated, and accurate lump coal rate statistics were provided. (2) Under the cutting stress, the coal body in the working face underwent three stages—microfracture generation, fracture expansion, and fracture penetration—to form lump coal, in which the fracture direction was orthogonal to the cutting pressure chain. Within a certain range from the roller, as the cutting depth of the roller increased, the number of new fractures in the coal body first increased and then stabilized. (3) Under the cutting stress, the fractured coal body was locally compressed, thereby forming a compact core. The formation and destruction of the compact core caused fluctuations in the cutting force. The fluctuation amplitude was positively related to the coal mass. (4) Because the simulation did not consider secondary damage in the coal, the simulated lump coal rate was larger than the actual lump coal rate in the working face; this deviation was mainly concentrated in large lump coal with a diameter greater than 300 mm.

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