Exploration and Numerical Analysis of Failure Characteristic of Coal Pillar Under Great Mining Height Longwall Influence

2016 ◽  
Vol 34 (2) ◽  
pp. 689-702 ◽  
Author(s):  
Jun Wang ◽  
Jinquan Jiang ◽  
Guangbo Li ◽  
Hao Hu
Keyword(s):  
Numerical Analysis ◽  
Coal Pillar ◽  
Failure Characteristic ◽  
Mining Height

scholarly journals Use of the Equivalent Mining Height Method for Understanding Overlying Strata Movement and Stress Distribution in an Isolated Coal Pillar

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yang Chen ◽  
Dong Li ◽  
Fuxing Jiang ◽  
Lili Zhang ◽  
Cunwen Wang ◽  
...  
Keyword(s):  
Progressive Failure ◽  
Coal Pillar ◽  
Significant Rise ◽  
Outer Side ◽  
Working Face ◽  
Key Points ◽  
Filling Method ◽  
Two Sides ◽  
Mining Height ◽  
Overlying Strata

In order to study the changing rules of displacement filed and stress field of overlying strata on isolated pillar with filling mining method, a self-designed model of isolated pillar with an equivalent mining height and a monitoring system of stress is employed to study the progressive failure of overlying strata and the changing rules of induced displacement and stress, as the equivalent mining height increases. The findings from the trial tests show the following: (1) When the equivalent mining height is small, the overlying strata on the isolated coal pillar only bend and subside, but the overlying strata located on the goafs of two sides remain stable. (2) As the equivalent mining height increases, the degree of stress concentration on section coal pillar will rise and produce plastic failure in the first place near large caving goaf. The strata can subside between isolated working face and adjacent large caving goaf. (3) As the equivalent mining height increases further, new cracks in the roof of isolated working face will unite the cracks of carving goaf on two sides in horizontal direction, leading to a significant rise of the height of cracks. Three goafs will evolve into a large carving goaf, and the vertical cracks on the outer side of the carving goaf intersect with one another to form “fracture band”. The research acquires the key points for prevention in mining the isolated coal pillar with filling method and provides guidelines to implement this technique and to prevent rock burst.

Numerical Analysis on Ground Pressure Feature in Fully Mechanized Coal Face

2013 ◽  
Vol 807-809 ◽  
pp. 2299-2303
Author(s):  
Wei Jian Yu ◽  
Tao Feng ◽  
Gang Ye Guo
Keyword(s):  
Numerical Analysis ◽  
Abutment Pressure ◽  
Numerical Procedure ◽  
Wall Rock ◽  
Coal Face ◽  
Distribution Form ◽  
Ground Pressure ◽  
Working Face ◽  
Set Up ◽  
Mining Height

Base on the fully mechanized coal face of 8113 (1) in LaoYingSan mine, numerical analysis method was applied to analyze the ground pressure feature, FLAC software is carried out to set up numerical model, and offer numerical procedure. The mining abutment pressure distribute form and its partition in front of fully mechanized working face. All four different mining height (2.6m2.8m3.0m3.2m) was respectively calculated. In addition, the influence of mining speed to mining abutment pressure and intervals is analyzed, four different mining distance (20m30m40m50m) selected separately. Afterwards, the different solution analyzed respectively, these results show that the mining abutment pressure distribution form in front of fully mechanized working face essentially identical, they including the stress increasing zones, the stress decreasing zones and the initial rock stress stable field. The influence of mining pace to wall rock looseness range greater than mining height.

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 Dynamic Evolution Law and Width Determination of Section Coal Pillars in Deep Mining Height Working Face

2021 ◽  
Author(s):  
Lei Zhaoyuan ◽  
Cui Feng ◽  
Liu Jianwei ◽  
Lai Xingping ◽  
Yi Ruiqiang
Keyword(s):  
Dynamic Instability ◽  
Coal Pillar ◽  
Field Measurements ◽  
Deep Mining ◽  
Evolution Law ◽  
Working Face ◽  
Large Mining Height ◽  
Coal Pillars ◽  
Lower Corner ◽  
Mining Height

Abstract The coal column undergoes three types of force evolution from the formation to the end of mining. This paper takes large mining height working face at No.2 Coal Mine as example to study the ways to avoid dynamic instability of the coal column triggered by the deep mining. By means of geological survey, theoretical analysis, numerical calculation and field verification, the load processes under the three stress stage are proposed, and the evolution law of the coal column is analyzed. The study shows that the depth, large mining height working face, coal pillar force and size altogether determine the damage characteristics of the coal pillar. With the combination of Flac3D and 3DEC, it can be analyzed that the plastic failure and displacement characteristics of the 35m coal column under the action of secondary dynamic load coincide. The perturbation stress distribution is stable, which finally determines the reasonable width of the 35m coal column. Field measurements show that the top and gang of the 35m coal column undergo three kinds of displacement characteristics. The lower part is more stable. The top plate of the upper and lower corner completely collapsed in the emptying area, which can play a good supporting role.

Study on Rational Width of Entry Protection Coal-Pillar in Large Mining Height Working Face

2011 ◽  
Vol 413 ◽  
pp. 404-409
Author(s):  
Xu Feng Wang ◽  
Dong Sheng Zhang ◽  
Ting Feng Cui ◽  
Jin Liang Wang ◽  
Wei Zhang
Keyword(s):  
Numerical Simulation ◽  
Theoretical Calculation ◽  
Coal Pillar ◽  
Engineering Practice ◽  
Pillar Width ◽  
Pillar Design ◽  
Working Face ◽  
Large Mining Height ◽  
Mining Height

This paper demonstrates the attempt to identify a reasonable chain pillar width in the condition of large mining height, along with a case study at the gateway of No.1103 panel with large mining height in Suancigou Mine. Theoretical calculation and numerical simulation were employed as the main approaches during the research to figure out the rational width of entry protection coal-pillar, which was then proved to be capable for engineering practice. The results that derived from our research can offer technical support for spot production, and serve as references for future investigation upon chain pillar design under large mining height.

scholarly journals Research on stress release for the gob-side roadway using the roof-cutting technology with a chainsaw arm

2020 ◽  
Vol 7 (3) ◽  
pp. 191663
Author(s):  
Yang Tai ◽  
Bin Yu ◽  
Binwei Xia ◽  
Zhao Li ◽  
Hongchu Xia
Keyword(s):  
Numerical Analysis ◽  
Coal Pillar ◽  
Deformation And Failure ◽  
Hard Roof ◽  
Working Face ◽  
Stress Relieving ◽  
Cutting Experiment ◽  
Pillar Mining ◽  
Coal Pillars ◽  
Cutting Height

The narrow pillar mining method is widely adopted for working faces in coal mines. However, in cases of an overlying hard roof, a suspended triangle roof plate or a cantilever will be formed near the goaf. At this point, the coal pillar extrusion and serious deformation will occur in the gob-side roadway. In order to mitigate the problem, the roof-cutting technology with a chainsaw arm and its equipment have been developed. In this paper, based on the analysis of deformation and failure characteristics of 2312 roadway, which is close to the goaf of 2311 working face in Tashan Coal, the roof-cutting technology with a chainsaw arm was chosen to be applied in 2311 roadway. Then, the roof-cutting process and the load acting on the coal pillar were discussed and analysed. A numerical model was established to analyse the stress releasing effects after roof cutting. Moreover, the roof-cutting height and the support parameters of the roadway were optimized through numerical analysis and the results manifested that the roof cutting was the most effective when the roof-cutting height was 6.4 m. After roof cutting, the vertical stresses within the coal pillars were lowered by about 25.0%. Finally, the roof-cutting experiment was carried out in the 2311 roadway in Tashan Coal Mine. The on-site roof-cutting depth was 6.4 m and the roof-cutting width was 42 mm guided by the numerical analysis. To verify the stress-relieving effects, the borehole stress meters were applied to monitor the peak advancing stresses of narrow pillars at various depths. The measured results indicated that the peak advancing stresses decreased by 22.8% on average, and therefore, roof cutting and stress releasing effects were achieved.

Research on Surrounding Rock Control Technology in Two Hard Fully Mechanized Coal Mining

2013 ◽  
Vol 868 ◽  
pp. 343-346
Author(s):  
Hong Chun Xia ◽  
Ru Nan Zhang ◽  
Wei Li
Keyword(s):  
Coal Pillar ◽  
Surrounding Rock ◽  
Efficient Production ◽  
Security Measures ◽  
Safety Requirements ◽  
Well Production ◽  
Production Safety ◽  
Large Mining Height ◽  
Surrounding Rock Control ◽  
Mining Height

The coal 8210 big mining height of the Datong mine Jin hua gong face in the process of mining airport coal pillar fried state a, floor deformation intense, serious kick drum, eventually leading to rock failure .In the severe cases, easily induced by shock pressure and other disasters ,these have serious impact on the efficient production of face security in the large mining height. by the airport side of roadway roof pressure relief, combined with roadway bolting reinforcement technology effectively control the deformation of surrounding rock of roadway, Test results show that the security measures taken can meet the well production safety requirements.

Research on Rational Width of Entry Protection Coal-Pillar in Large Mining Height Work-Face of Shallow Coal Seam

2014 ◽  
Vol 1010-1012 ◽  
pp. 1461-1466
Author(s):  
Xin Bin Xu ◽  
Bang Jun Wang ◽  
Ting Feng Cui
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Theoretical Calculation ◽  
Coal Pillar ◽  
Engineering Practice ◽  
Large Mining Height ◽  
Shallow Coal Seam ◽  
Mining Face ◽  
Mining Height

For the study on the problem of rational width of entry protection coal-pillar, according to the gateway of 5103 mining face in Heshan Mine, through theoretical calculation and numerical simulation, rational width of entry protection coal-pillar was educed, which was 25 m. The roof and floor and 2-sides deformation were both 35 mm through engineering practice, and its feasibility was demonstrated, which provided some theoretical references for preserving reasonable coal-pillar for the similar coalface with large mining height.

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