scholarly journals Coal Mine Abutment Pressure Distribution Based on a Strain-Softening Model

2020 ◽  
Vol 8 ◽  
Author(s):  
Ang Li ◽  
Qiang Ma ◽  
Li Ma ◽  
Li Kang ◽  
Qian Mu ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Coal Mine ◽  
Abutment Pressure ◽  
Strain Softening

Reasonable Entry Layout of Lower Seam in Multi-Seam Mining Based on Numerical Simulation

2013 ◽  
Vol 295-298 ◽  
pp. 2980-2984
Author(s):  
Xiang Qian Wang ◽  
Da Fa Yin ◽  
Zhao Ning Gao ◽  
Qi Feng Zhao
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Coal Seam ◽  
Coal Mine ◽  
Abutment Pressure ◽  
Surrounding Rock ◽  
Geological Conditions ◽  
Seam Mining

Based on the geological conditions of 6# coal seam and 8# coal seam in Xieqiao Coal Mine, to determine reasonable entry layout of lower seam in multi-seam mining, alternate internal entry layout, alternate exterior entry layout and overlapping entry layout were put forward and simulated by FLAC3D. Then stress distribution and displacement characteristics of surrounding rock were analyzed in the three ways of entry layout, leading to the conclusion that alternate internal entry layout is a better choice for multi-seam mining, for which makes the entry located in stress reduce zone and reduces the influence of abutment pressure of upper coal seam mining to a certain extent,. And the mining practice of Xieqiao Coal Mine tested the results, which will offer a beneficial reference for entry layout with similar geological conditions in multi-seam mining.

scholarly journals A New Closed-Form Solution of the Side Abutment Pressure Distribution of Roadway

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Liang Cheng ◽  
Yidong Zhang
Keyword(s):  
Plastic Zone ◽  
Pressure Distribution ◽  
Closed Form ◽  
Abutment Pressure ◽  
Closed Form Solution ◽  
Evaluation Process ◽  
Friction Angle ◽  
Form Solution ◽  
Closed Form Solutions ◽  
Roadway Stability

Instability of coal wall is one of the hot-button and difficult issues in the study of coal mine ground control. The shallow side coal of roadway in the coal measures is usually weak and consequently easy to bring about failure. Hence, the side abutment pressure redistributes and dramatically influences the roadway stability. Since the previous closed-form solutions of the side abutment pressure do not take into account all the necessary parameters which include the properties of the coal and the interface between coal and roof/floor, the roadway height, and the support strength, a mechanical model is established based on the equilibrium of the plastic zone, and a new closed-form solution is derived in this paper. Moreover, a numerical investigation is conducted to validate the accuracy of the closed-form solution. The numerical results of the side abutment pressure distribution are in good agreement with the closed-form solution. Afterwards, a parametric analysis of the width of the plastic zone is carried out, and the results show that the width of the plastic zone is nearly negatively linearly correlated with the friction angle and the cohesion of the coal, the interfacial cohesion, and the support strength. By contrast, it is positively linearly correlated with the roadway height and negatively exponentially correlated with the interfacial friction angle. The results obtained in the present study could be useful for the evaluation process of roadway stability.

scholarly journals Experimental Investigation of Water-Inrush Risk Based on Permeability Evolution in Coal Mine and Backfill Prevention Discussion

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Meng Li ◽  
Jixiong Zhang ◽  
Weiqing Zhang ◽  
Ailing Li ◽  
Wei Yin
Keyword(s):  
Experimental Investigation ◽  
Coal Mine ◽  
Strain Softening ◽  
Water Inrush ◽  
Rock Fractures ◽  
Permeability Evolution ◽  
Testing Laboratories ◽  
Fracture Development ◽  
Confining Pressures ◽  
Maximum Permeability

Induced by coal mining, the fractures constantly occur in geologic strata until failure occurs, which provide channels for water flow. Therefore, it is essential to investigate the permeability evolution of rocks under load. Borehole sampling was conducted in a bedrock layer beneath an aquifer, and the permeability evolution of sandstone specimens under different confining pressures was tested in rock mechanics testing laboratories. The results indicated that the permeability gradually decreases with the increasing confining pressures, while the peak strength increases with the increase of confining pressures. The minimum and maximum permeabilities occurred in the sandstone specimens that were subjected to elastic deformation and strain-softening stages, respectively. The failure, and maximum permeability, of these sandstone specimens did not occur simultaneously. To prevent the flow channel being formed due to the development and failure of rock fractures, a method of backfill gob was proposed and also the influence of backfill on fracture development was discussed.

scholarly journals Abutment pressure distribution for longwall face mining through abandoned roadways

2019 ◽  
Vol 29 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Yang Li ◽  
Mingxing Lei ◽  
Haosen Wang ◽  
Cheng Li ◽  
Weiwei Li ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Abutment Pressure ◽  
Longwall Face

scholarly journals Comprehensive Measurement of the Deformation and Failure of Floor Rocks: A Case Study of the Xinglongzhuang Coal Mine

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Hao Liu ◽  
Pu Wang ◽  
Weihe Zhang ◽  
Qiang Liu ◽  
Lijun Su
Keyword(s):  
Coal Mine ◽  
Abutment Pressure ◽  
Three Dimensional ◽  
Strain Sensing ◽  
Floor Rock ◽  
Deformation And Failure ◽  
Working Face ◽  
Floor Failure ◽  
Coal Wall ◽  
Different Depths

The isolated island panel 10304 of the Xinglongzhuang coal mine was used as the research subject to study the deformation and damage characteristics of the coal seam floor. The damage of the floor was studied using the borehole strain sensing method and borehole imaging technology, and FLAC3D was used to study the influence of abutment pressure on floor failure. The result shows that the floor under the superimposed area which is affected by lateral and advanced abutment pressure is damaged firstly, and the maximum depth reaches 26 m, other areas of the working face about 23 m. The degree of deformation and failure of floor rock at different depths is decreased. The deformation damage increases with the advancement of the working face until a certain distance at the same depth. The hole image can clearly show the influence range of the abutment pressure in front of the coal wall and influence the degree of the advancement and lag by means of the strain increment curve for each sensor probe and the images from different drilled positions. On the basis that the results of simulation and field measurement are consistent, the results can reflect the three-dimensional failure characteristics of the whole island working face floor in the process of coal mining more comprehensively and accurately; moreover, they also can provide important information for mine flood prevention and ecological environment protection.

Study on Abutment Pressure Distribution Law of Fully-Mechanized Sublevel Caving Face in Extra-Thickness

2015 ◽  
Vol 1094 ◽  
pp. 405-409
Author(s):  
Lei Yu
Keyword(s):  
Pressure Distribution ◽  
Abutment Pressure ◽  
Distribution Law ◽  
Working Face ◽  
Sublevel Caving ◽  
Coal Wall ◽  
Pressure Peak ◽  
Cutting Height ◽  
Coal Seam Thickness ◽  
Peak Value

Based on field observation, analogy simulation and theoretical analysis, the abutment pressure distribution law of fully-mechanized sublevel caving face with extra-thickness was studied. The results showed that: Different instability type of the structure ‘Combined cantilever beam-articulated rock beam’ in fully-mechanized sublevel caving roof led to cyclical changes of abutment pressure; with an invariable coal seam thickness and increasing cutting height, abutment pressure peak value tended to stabilize after reaching the maximum, but as the working face advancing its location transferred to the front of coal wall working face and the influence region of abutment pressure increased; with an invariable cutting height and increasing once mining thickness, abutment pressure peak value decreased, and the distance between peak point and coal wall and the influence region increased. The results of the study would have some guiding role in extra-thickness fully mechanized mining’s safety and efficiency.

Experimental Research on Critical Force of Crushing and Sorting Coal Mine Gangue

2013 ◽  
Vol 329 ◽  
pp. 26-30
Author(s):  
Wen Xiang Zheng ◽  
Ming Sun ◽  
Wan Dong Han
Keyword(s):  
Experimental Data ◽  
Pressure Distribution ◽  
Coal Mine ◽  
Distribution Curve ◽  
Graphical Analysis ◽  
Critical Force ◽  
Particle Sizes ◽  
Pressure Test ◽  
Future Work ◽  
Curve Equation

First, The pressure test on two actual coal mine irregular and different particle sizes of coal and gangue, through the experimental data, using MATLAB software to give a graphic simulation and assumptions test of normal distribution, by the graphics and hypothetical test confirmed that coal and gangue had obvious demarcation, namely the critical force of crushing and storing coal gangue. In a coal mine as an example,and acquisiting more irregular and different particle sizes of coal and gangue were broken by static experiments and dynamic crushing experiment, using the experimental data obtained pressure distribution and pressure distribution curve equation,by equation to solve the crushing critical force FL of the size of 50-90mm coal and gangue,through mathematical and graphical analysis proved the rationality of FL,and providing a basic data for the future work.

scholarly journals Influence of Upper Seam Extraction on Abutment Pressure Distribution during Lower Seam Extraction in Deep Mining

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Feng Wang ◽  
Zeqi Jie ◽  
Bo Ma ◽  
Weihao Zhu ◽  
Tong Chen
Keyword(s):  
Coal Seam ◽  
Pressure Distribution ◽  
Abutment Pressure ◽  
Field Measurements ◽  
Pressure Relief ◽  
Deep Mining ◽  
Key Strata ◽  
Mining Safety ◽  
Seam Mining ◽  
Overlying Strata

Pressure-relief coal mining provides an effective way to decrease stress concentration in deep mining and ensures mining safety. However, there is currently a lack of research and field verification on the pressure-relief efficiency and influencing factors during upper seam extraction on the lower seam. In order to make up for this deficiency, in this study, field measurements were conducted in panel Y485, which has a maximum depth of 1030 m and is partially under the goaf of the upper 5# seam in the Tangshan coal mine, China, and evolution of advanced abutment pressure was analyzed. Numerical simulations were conducted to study of influence of key strata on advanced abutment pressure. Influence mechanisms of the upper seam extraction on the advanced abutment pressure distribution during lower seam extraction were revealed. The results indicate that the distribution of advanced abutment stress is influenced by the key strata in the overlying strata. The key strata above the upper coal seam were fractured due to the upper coal seam mining, and the advanced abutment stress was only influenced by the key strata between the two seams during lower coal seam mining. When key strata were present between two seams, the extraction of the lower seam still faces potential dynamic disasters after the extraction of the upper seam. In this case, it would be necessary to fracture the key strata between the two seams in advance for the purpose of mining safety. Key strata in the overlying strata of the 5# seam were fractured during extraction, and advanced abutment pressure was only influenced by the key strata located between the two mined seams. The influence distance of advanced abutment pressure in panel Y485 decreased from 73 m to 38 m, and the distance between the peak advanced abutment pressure and the panel decreased from 29 m to 20.5 m, achieving a pronounced pressure-relief effect.

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