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 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.

Numerical Simulation of Strata Behavior in Super-Long and Large Mining Height Working Face

2013 ◽  
Vol 634-638 ◽  
pp. 3428-3432 ◽  
Author(s):  
Zhi Hua Li ◽  
Xin Zhu Hua ◽  
Ruo Jun Zhu ◽  
De Sheng Zhou
Keyword(s):  
Abutment Pressure ◽  
Roof Displacement ◽  
Mining Depth ◽  
Working Face ◽  
Face Length ◽  
Coal Wall ◽  
Large Mining Height ◽  
Strata Behavior ◽  
Behavior Characteristics ◽  
Mining Height

In order to study the strata behavior characteristics in super-long and large mining height working face, the FLAC-3D software was used to study the roof displacement and the abutment pressure distribution laws of working faces. The results indicate that: ① the influence range is larger of front abutment pressure in Liuzhuang coal mine 171301 super-long large mining height working face, and reaches to 60m. ② the maximum roof displacement increases with the increase of mining depth and working face length, the increase in magnitude decreases gradually, while the maximum roof displacement sharply increases due to the increase of mining height. ③ the peak abutment pressure increases with the increase of mining depth and mining height, the location of peak abutment pressure transfer to ahead of the coal wall. ④ the effect of working face length on abutment pressure is very feeble, so, the strata behavior characteristics remain almost constant with the increase of face length.

Numerical Analysis of Influencing Factors of Stability in Thick Coal Seam Mining Roadway

2012 ◽  
Vol 256-259 ◽  
pp. 1453-1457
Author(s):  
Zhi Hua Li ◽  
Xin Zhu Hua ◽  
Ke Yang ◽  
Ruo Jun Zhu ◽  
De Sheng Zhou
Keyword(s):  
Coal Seam ◽  
Abutment Pressure ◽  
Surrounding Rock ◽  
Rock Body ◽  
Thick Coal Seam ◽  
Mining Depth ◽  
Working Face ◽  
Face Length ◽  
Seam Mining ◽  
Mining Height

The FLAC-3D software was used to study the surrounding rock displacement and the side abutment pressure distribution laws about roadway in thick coal seam. Based on this model, through change the mining height, working face length and mining depth, the differences of roadway underground pressure characteristics were analyzed between thick coal seam working face and normal working face. The results indicate that: ①the displacement of roadway surrounding rock increases with the increase of mining depth and mining height, the closer to the coal wall the larger of the increase range of roadway displacement. ②the peak of side abutment pressure increases with the increase of mining depth and mining height, the peak district of the stress will move toward the inner department of rock body. ③ the effect of working face length on the roadway displacement and the side abutment pressure is very feeble.

Measurement and Analysis for Gas Emission Characters in Fully Mechanized Caving Face

2013 ◽  
Vol 353-356 ◽  
pp. 2331-2336
Author(s):  
Xin Jian Li ◽  
Shou Song Guo ◽  
Jun He ◽  
Xiang Fan Mi
Keyword(s):  
Abutment Pressure ◽  
Coal Production ◽  
Coal Face ◽  
Gas Emission ◽  
Obvious Effect ◽  
Gas Concentration ◽  
Working Face ◽  
Measurement And Analysis ◽  
Working Resistance ◽  
The Relationship

According to the practical condition of 3401 fully mechanized caving face in Dayang coal mine, the relationship between strata behaviors, mining technology and stope gas emission are analyzed through real-time monitoring of the support working resistance, advance abutment pressure and gas concentration of working face. It shows that the change of working face abutment pressure has an obvious effect on the regularity of coal face gas emission. The crest value of gas emission falls behind periodic weighting, the lagging time is about one day. Other factors, like coal production processes, daily coal output and advance speed also have close relationships with gas emission.

scholarly journals A Method Based on Elastic Mechanics for Judging Compound Hard Roof and Its Application

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Haiyang Wang ◽  
Xiang Chen ◽  
Yanmin Zhou ◽  
Binwei Xia ◽  
Jie Wang ◽  
...  
Keyword(s):  
Stress Field ◽  
Mechanical Model ◽  
Large Deviation ◽  
Similar Model ◽  
Coal Face ◽  
Hard Roof ◽  
Working Face ◽  
The Common ◽  
Set Up ◽  
Elastic Mechanics

Compound hard roof overlying coal face is the common disaster factor leading to strong strata behaviors. To solve the long-standing problems of only considering partial factors and large deviation from the actuality when identifying compound hard roof, a mechanical model of compound hard roof based on elastic mechanics is built, from which the stress field distribution equations of compound hard roof are formed and the judging criteria of compound hard roof have been set up. In this essay, 8101 Working Face of Tashan Coal Mine in China is the research object for criteria and analysis of compound hard roof, and the result is testified by similar model tests. The research results have provided a basis for judging and dealing with compound hard roof.

scholarly journals The Effect of Joint Damage on a Coal Wall and the Influence of Joints on the Abutment Pressure on a Fully Mechanised Working Face with Large Mining Height

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Weibin Guo ◽  
Shengwei Zhang ◽  
Yuhui Li
Keyword(s):  
Abutment Pressure ◽  
Limit Equilibrium ◽  
Technical Problem ◽  
Damage Variable ◽  
Joint Spacing ◽  
Working Face ◽  
Coal Wall ◽  
Large Mining Height ◽  
Dip Angle ◽  
Mining Height

Coal wall spalling is regarded as a key technical problem influencing safe and efficient mining of large-mining-height working faces while the distribution of abutment pressure within the limit equilibrium zone (LEZ) influences coal wall spalling within a large-mining-height working face. This research attempted to explore the distribution characteristics of abutment pressure within the LEZ in a large-mining-height working face. For this purpose, the influences of the orientation of joints on mechanical characteristics of coal with joints and on the distribution of abutment pressure within the LEZ in the large-mining-height working face were analysed by theoretical analysis and numerical simulation. Research results show that the damage variable of coal with joints first rises, then decreases, and finally increases with increasing dip angle of the joints; as the azimuth of the joints increases, the damage variable first declines, then increases; the damage variable gradually declines with increasing joint spacing; an increase in the dip angle of joints corresponds to first reduction, then growth, and a final decrease of the abutment pressure at the same position in front of the coal walls; on certain conditions, the abutment pressure at the same position within the LEZ first rises, then declines as the azimuth of joints increases; with the growth of the joint spacing, the abutment pressure at the same position within the LEZ rises. The dip angle and azimuth of joints marginally affect the abutment pressure within the LEZ.

Reasons of Great Mining Height Coal Side Fall and Study of Supports Preventing Technology

2013 ◽  
Vol 744 ◽  
pp. 244-247
Author(s):  
Li Ping Wang ◽  
Cai Ying Zhai ◽  
Wei Min Huang
Keyword(s):  
Quantitative Analysis ◽  
Theoretical Basis ◽  
Coal Face ◽  
Factors Influencing ◽  
Working Face ◽  
Mining Height

In order to control the side fall of coal face in great mining height fully mechanized face,this paper proposes a way of controling side fall by ensuring supports setting force,accelerating development,supporting timely of the fully mechnized face and making good use of supports sprag units on the basis of side fall influence study and side fall principle analysis. This paper not only analyses factors influencing stability and explains kinds of sprag units phenomenon of coal face in working face but also conducts quantitative analysis on the influence and provides theoretical basis for measures in order to prevent coal side fall in working face.Meantime,those measures this paper provides are all effectively in controlling coal side fall in great mining height fully mechanized.

scholarly journals Stress and deformation analysis of gob-side pre-backfill driving procedure of longwall mining: a case study

2021 ◽  
Author(s):  
Rui Wu ◽  
Penghui Zhang ◽  
Pinnaduwa H. S. W. Kulatilake ◽  
Hao Luo ◽  
Qingyuan He
Keyword(s):  
Rock Mass ◽  
Stress Distribution ◽  
Coal Seam ◽  
Abutment Pressure ◽  
Longwall Mining ◽  
Vertical Stress ◽  
Floor Level ◽  
Working Face ◽  
Floor Heave ◽  
Stress And Deformation

AbstractAt present, non-pillar entry protection in longwall mining is mainly achieved through either the gob-side entry retaining (GER) procedure or the gob-side entry driving (GED) procedure. The GER procedure leads to difficulties in maintaining the roadway in mining both the previous and current panels. A narrow coal pillar about 5–7 m must be left in the GED procedure; therefore, it causes permanent loss of some coal. The gob-side pre-backfill driving (GPD) procedure effectively removes the wasting of coal resources that exists in the GED procedure and finds an alternative way to handle the roadway maintenance problem that exists in the GER procedure. The FLAC3D software was used to numerically investigate the stress and deformation distributions and failure of the rock mass surrounding the previous and current panel roadways during each stage of the GPD procedure which requires "twice excavation and mining". The results show that the stress distribution is slightly asymmetric around the previous panel roadway after the “primary excavation”. The stronger and stiffer backfill compared to the coal turned out to be the main bearing body of the previous panel roadway during the "primary mining". The highest vertical stresses of 32.6 and 23.1 MPa, compared to the in-situ stress of 10.5 MPa, appeared in the backfill wall and coal seam, respectively. After the "primary mining", the peak vertical stress under the coal seam at the floor level was slightly higher (18.1 MPa) than that under the backfill (17.8 MPa). After the "secondary excavation", the peak vertical stress under the coal seam at the floor level was slightly lower (18.7 MPa) than that under the backfill (19.8 MPa); the maximum floor heave and maximum roof sag of the current panel roadway were 252.9 and 322.1 mm, respectively. During the "secondary mining", the stress distribution in the rock mass surrounding the current panel roadway was mainly affected by the superposition of the front abutment pressure from the current panel and the side abutment pressure from the previous panel. The floor heave of the current panel roadway reached a maximum of 321.8 mm at 5 m ahead of the working face; the roof sag increased to 828.4 mm at the working face. The peak abutment pressure appeared alternately in the backfill and the coal seam during the whole procedure of "twice excavation and mining" of the GPD procedure. The backfill provided strong bearing capacity during all stages of the GPD procedure and exhibited reliable support for the roadway. The results provide scientific insight for engineering practice of the GPD procedure.

scholarly journals Safety Warning Model of Coal Face Based on FCM Fuzzy Clustering and GA-BP Neural Network

Symmetry ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1082
Author(s):  
Fanqiang Meng
Keyword(s):  
Neural Network ◽  
Genetic Algorithm ◽  
Early Warning ◽  
Back Propagation ◽  
Back Propagation Neural Network ◽  
Coal Face ◽  
Early Warning Model ◽  
Working Face ◽  
The Neural Network ◽  
Warning Model

Risk and security are two symmetric descriptions of the uncertainty of the same system. If the risk early warning is carried out in time, the security capability of the system can be improved. A safety early warning model based on fuzzy c-means clustering (FCM) and back-propagation neural network was established, and a genetic algorithm was introduced to optimize the connection weight and other properties of the neural network, so as to construct the safety early warning system of coal mining face. The system was applied in a coal face in Shandong, China, with 46 groups of data as samples. Firstly, the original data were clustered by FCM, the input space was fuzzy divided, and the samples were clustered into three categories. Then, the clustered data was used as the input of the neural network for training and prediction. The back-propagation neural network and genetic algorithm optimization neural network were trained and verified many times. The results show that the early warning model can realize the prediction and early warning of the safety condition of the working face, and the performance of the neural network model optimized by genetic algorithm is better than the traditional back-propagation artificial neural network model, with higher prediction accuracy and convergence speed. The established early warning model and method can provide reference and basis for the prediction, early warning and risk management of coal mine production safety, so as to discover the hidden danger of working face accident as soon as possible, eliminate the hidden danger in time and reduce the accident probability to the maximum extent.

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