scholarly journals Study on the Mine Pressure Law and the Pressure Frame Mechanism of an Overlying Goaf in a Shallow Coal Seam

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Haifeng Zhou ◽  
Qingxiang Huang ◽  
Yingjie Liu ◽  
Yanpeng He
Keyword(s):  
Coal Pillar ◽  
Coal Extraction ◽  
Mine Pressure ◽  
Prevention Measures ◽  
Overburden Pressure ◽  
Load Pressure ◽  
Working Face ◽  
Coal Wall ◽  
Numerical Simulation Methods ◽  
Mining Face

To study the problems of dynamic load pressure and frame pressure caused by the concentration of stress by coal extraction pillars during the mechanized short-distance mining of goaves in shallow coal seams, a frame pressure accident, in the Shendong Shigetai Coal Mine, during the overlying of a fully mechanized mining goaf is taken as a research example. By applying the field measurement, theoretical analysis, and numerical simulation methods, we throughly analysed the working face coal pillar, got the regular pattern of fully mechanized overburden pressure, summarized a pillar of fully mechanized working face in the overburden strata movement regularity and development characteristics, analyzed the reason and mechanism of broken coal pillar, and put forward the corresponding prevention measures and management method. The results show that when the fully mechanized mining face enters the goaf by about 3 m, the pressure arches of the lower coal face and the upper goaf arising from the extracted coal overlap. When the vertical stress is greater than the supporting force of the hydraulic support and the coal wall, a roof ejection accident may occur.

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.

Study on Pressure Regularity of the Fully Mechanized Coal Mining Face and Evaluation on Support Adaptability

2013 ◽  
Vol 734-737 ◽  
pp. 838-842
Author(s):  
Xing Shun Wang
Keyword(s):  
Theoretical Analysis ◽  
Coal Mining ◽  
Rock Pressure ◽  
Field Testing ◽  
Mine Pressure ◽  
Pressure Monitoring ◽  
Technical Parameters ◽  
Analysis And Evaluation ◽  
Working Face ◽  
Mining Face

Based on the theoretical analysis and field testing, for making clear of the roofs strata behaviors characteristics in the fully mechanized coal mining face in Hongliulin coal mine, and evaluating the adaptability of the support to the roof movement of the working face, this paper gives a collection analysis and evaluation of the rock pressure information during the working faces extraction to get the related technical parameters that can reflect the roof activity rule and the support adaptability analysis and meanwhile to provide some references for the mine pressure monitoring under the similar conditions.

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.

scholarly journals Simulation Analysis and Engineering Application of Retaining Width of Waterproof Coal Pillar in Island Working Face

2021 ◽  
Author(s):  
Lili Zheng ◽  
Zheng Gao
Keyword(s):  
Service Life ◽  
Simulation Analysis ◽  
Engineering Application ◽  
Coal Pillar ◽  
Surrounding Rock ◽  
Simulation Research ◽  
Working Face ◽  
Before And After ◽  
Mining Face ◽  
Coal Pillars

The old mining area in Pingdingshan coalfield has the following problems: long mining service life, many remaining coal pillars, and great difficulty in mining; to extend the service life of the mine, realize cost saving and efficiency increasing, it is urgent to recover the remaining coal pillars, but the mining of isolated island face faces the problem of reasonable retention of waterproof coal pillars, if the protection is not good, it is easy to cause mine water damage and increase the mining cost. Therefore, in view of the practical engineering problems faced by the field, aiming at eliminating or reducing the goaf water disaster, this paper adopts numerical simulation research methods to optimize the original design scheme and carry out comparative analysis, dynamically reappear the surrounding rock stress field, displacement field and plastic failure law under multi face mining and roadway mining, and carry out engineering practice application. The results show that there is a certain thickness of elastic core area before and after mining with 25m coal pillar width. The deformation of surrounding rock is small, which is conducive to roadway maintenance, without obvious stress concentration. It can meet the actual needs of the project. The mining face has achieved safe mining, without water inrush accident in the goaf, and the coal resources have been recovered to the maximum extent. The research results are left over to similar mining areas in China The safe recovery of coal pillar can be used for reference.

Research on Mine Pressure Behave Law in Mining of Face under the Coal Pillar

2011 ◽  
Vol 217-218 ◽  
pp. 1721-1724
Author(s):  
Wei Shi ◽  
Hong Tao Liu ◽  
Cui Liang ◽  
Hou Sheng Jia
Keyword(s):  
Recovery Rate ◽  
Coal Pillar ◽  
Mine Pressure ◽  
Regular Pattern ◽  
Lower Face ◽  
Working Face ◽  
Correct Understanding ◽  
Close Distance ◽  
Protection Pillar

When mining close-distance seams with downlink mining, in order to benefit roof maintenance and management, the decoration of lower seam roadways should try to avoid the area affected by pillar concentrated stress , using inside cross decorationg; In order to improve the recovery rate of resources, the size of protection pillar can’t be too big, when mining under pillar of upper layer and mining in pillar of upper layer with crossing. The whole lower face or some phase located under the influence of upper coal concentration stress, give roadways and working face roof maintenance a lot of difficulties. Then it appeared the conflict between security and economy, to solve this problem, we must return to the correct understanding of mine pressure behave law. In the paper, through the investigation of the typical dozen example in mining of face the coal pillar in China, to get its regular pattern of mine pressure behave, in similar conditions mining, there will be important reference and guidance.

Study on Mine Pressure Behavior of Roadway in Highly Irregular Working Face in Daizhuang Coal Mine

2012 ◽  
Vol 256-259 ◽  
pp. 1443-1446
Author(s):  
Xing Lin Wen ◽  
Lin Hai Gao ◽  
Chuan Lei Li ◽  
Meng Meng Dong
Keyword(s):  
Coal Mine ◽  
Surrounding Rock ◽  
Mine Pressure ◽  
Mining Engineering ◽  
Deformation Characteristics ◽  
Working Face ◽  
Production Safety ◽  
Support Force ◽  
Mining Face ◽  
Important Significance

The irregular face mechanized mining is one of the difficult problems in the field of mining engineering. In this thesis, the roadways of 4324 extremely irregular face in DaiZhuang Mine were taken as research object. Through on-site mine pressure observation, the deformation characteristics of the surrounding rock and support force was analyzed. Next the mine pressure appeared rule of the roadways was study. This study benefited that the production of 4324 mining face went on wheels, at the same time, it had important significance to production safety of irregular working face with similar conditions.

scholarly journals A Study on the Mechanism of Dynamic Pressure during the Combinatorial Key Strata Rock Column Instability in Shallow Multi-coal Seams

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Jie Zhang ◽  
Bin Wang ◽  
Wenyong Bai ◽  
Sen Yang
Keyword(s):  
Dynamic Load ◽  
Dynamic Pressure ◽  
Coal Pillar ◽  
Mine Pressure ◽  
Key Strata ◽  
Column Type ◽  
Type Fracture ◽  
Mining Face ◽  
Rock Column ◽  
Overlying Strata

In order to study the pressure changes and support failure in mining face under concentrated coal pillar in shallow coal seam, the concentrated coal pillar in 30105 working face of Nan Liang Coal Mine was selected as the research object. In this study, the mechanism of dynamic mine pressure in mining face under concentrated coal pillar was investigated through multiple simulation experiments, numerical simulations, and theoretical analysis. The results of similar simulation experiment indicate that the dynamic mine pressure occurred at 25 m under the concentrated coal pillar and 7 m beyond the coal pillar. The strata roof was observed with sliding down, resulting in collapse and severe fractures commonly seen in rock column. The overlying strata caused the overall subsidence and collapse synchronously, resulting in the sudden increase of the resistance of the support in the working face, and the dynamic load coefficients reach 3.4 and 3.5. The theoretical analysis indicates that the two hard strata in the overlying strata of 3−1 coal meet the theoretical criterion of the combined key strata with the concentrated coal pillar of 2−2 coal in the weak interlayer of the combined key strata. The combined key strata bear the load of the whole overlying strata. The sliding instability featured with the rock column-type fracture located in the combined key strata is considered as the primary trigger of the abnormal resistance of the support and the dynamic mine pressure in the mining face under the concentrated coal pillar. The dynamic pressure model of “combination key strata—immediate roof-support” was established, along with the dynamic load coefficient calculation related to the rock column-type fracture and instability. The characteristics of dynamic load coefficient of the rock column-type fracture and instability under different overlying rock structure conditions were analyzed, providing references and insights into mining under similar geographic conditions.

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 PFC2D. 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.

scholarly journals Stability Analysis of Roadway Groups under Multi-Mining Disturbances

2021 ◽  
Vol 11 (17) ◽  
pp. 7953
Author(s):  
Yuantian Sun ◽  
Ruiyang Bi ◽  
Qingliang Chang ◽  
Reza Taherdangkoo ◽  
Junfei Zhang ◽  
...  
Keyword(s):  
Coal Mining ◽  
Coal Pillar ◽  
Stability Control ◽  
Surrounding Rock ◽  
Key Strata ◽  
Working Face ◽  
Roadway Stability ◽  
Mining Disturbance ◽  
Mining Face ◽  
The Stability

The roadway stability has been regarded as the main challenging issue for safety and productivity of deep underground coal mines, particularly where roadways are affected by coal mining activities. This study investigates the −740 m main roadway in the Jining No. 2 Coal Mine to provide a theoretical basis for the stability control of the main deep roadway affected by disturbances of adjacent working activities. Field surveys, theoretical analyses, and numerical simulations are used to reveal mechanisms of the coal mining disturbance. The field survey shows that the deformation of roadway increases when the work face advances near the roadway group. Long working face mining causes the key strata to collapse based on the key strata theory and then disturbs the adjacent roadway group. When the working face is 100 m away from the stop-mining line, the roadway group is affected by the mining face, and the width roadway protection coal pillar is determined to be about 100 m. Flac3D simulations prove the accuracy of the theoretical result. Through reinforcement and support measures for the main roadway, the overall strength of the surrounding rock is enhanced, the stability of the surrounding rock of the roadway is guaranteed, and the safe production of the mine is maintained.

Research on Stability of Overburden Structure around Longwall Mining Face in Steeply Dipping Seam Group

2015 ◽  
Vol 724 ◽  
pp. 100-110
Author(s):  
Shi Guang Ren ◽  
Yong Ping Wu ◽  
Jian Hui Yin
Keyword(s):  
Coal Seam ◽  
Longwall Mining ◽  
Coal Pillar ◽  
Beam Theory ◽  
Coal Seams ◽  
Working Face ◽  
Rock Structure ◽  
Longitudinal Bending ◽  
Mining Face ◽  
The Stability

The steeply dipping seam group is defined by the two or more coal seams ,a pitch between 35°~55°. Using masonry beam theory, longitudinal bending theory and “R-S-F” dynamics control theory built a lower area overburden structure mode. Analysed the stability of low position coal seam. The balance requirement and the strength of the structure which is affected by the caving rock and lower coal roof were given. It easily generates two lower position steps rock structure in inclination along working face. Regular breaking of the second structure is the main reason leads to the imbalance of the structure between upper coal pillar and upper coal mining face.The interaction among multiple coal seam panels and overburden structures is the main reason that causes the rock disaster, the unbalance of the lower area may lead to pushing accident, the imbalance of the upper area can generate shock pressure.

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