scholarly journals Quantitative Analysis and Evaluation of Coal Mine Geological Structures Based on Fractal Theory

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1925
Author(s):  
Gaizhuo Zhang ◽  
Junzhong Guo ◽  
Bin Xu ◽  
Lulu Xu ◽  
Zhenxue Dai ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Quantitative Analysis ◽  
Coal Mining ◽  
Fractal Theory ◽  
Northern China ◽  
Geological Structure ◽  
Coal Production ◽  
Structure Development ◽  
Analysis And Evaluation ◽  
Mining Areas

With the increasing depth of coal mining, the quantitative evaluation of the degree of geological structure development is becoming increasingly important for the control of mine water hazards in coal mining areas. Understanding the complexity of geological structure development can improve the safety and efficiency of coal production. At present, various evaluation indicators of the geological structure development cannot fully reflect the complexity of faults and folds, and the evaluation process is usually affected by subjective human factors. In this paper, the fractal dimension from fractal theory is used as the evaluation indicator to quantitatively analyze and evaluate the complexity of fault and fold structure in the mining area. To verify the evaluation results, the mathematical geology method is applied in an analysis of the trend surface of fault and fold networks. The results indicate that the fractal dimension can be applied for the quantitative analysis and evaluation of the complexity of fault and fold networks. In addition, the outcome of this work provides new insights into how to characterize the fault and fold structures of coal mining areas in northern China, and has some important implications to ensure the coal production safety.

Quantitative Analysis for Micro Geometrical Characteristic of Rough Surface Profile Based on Fractal Theory

2010 ◽  
Vol 154-155 ◽  
pp. 19-22
Author(s):  
Xiu Juan Yang ◽  
Zhi Qian Xu ◽  
Xiang Zhen Yan
Keyword(s):  
Surface Roughness ◽  
Fractal Dimension ◽  
Quantitative Analysis ◽  
Rough Surface ◽  
Vertical Section ◽  
Fractal Theory ◽  
Surface Profile ◽  
Fractal Dimensions ◽  
Geometrical Characteristic ◽  
Accuracy Requirement

In this paper, a quantitative analysis for the micro geometrical characteristic of rough surface profile is researched with the fractal theory. Firstly, the fractal dimensions of profile curves under different surface roughness are obtained by using the vertical section method, and then the theoretical relationship between the surface roughness and the fractal dimension is built. Secondly, according to the surface profile curve composed of many triangle peaks, the angles and heights of them are calculated to study the micro geometrical size. Through their variation laws changing with the fractal parameters, the calculation formulas of their average values related to fractal dimension are obtained by using mathematics regression tools. Finally, combing three theoretical relationships built above, the geometrical characteristic of the rough surface profile can be calculated with the surface roughness and accuracy requirement known.

Chances and Threats of Hard Coal Mining Development in Poland – The Results of Experts Research/Szanse I Zagrożenia Dla Rozwoju Górnictwa Węgla Kamiennego W Polsce – Wyniki Badań Eksperckich

2014 ◽  
Vol 59 (2) ◽  
pp. 395-411 ◽  
Author(s):  
Józef Dubiński ◽  
Marian Turek
Keyword(s):  
Coal Mining ◽  
Present Situation ◽  
Hard Coal ◽  
Coal Production ◽  
Actual Situation ◽  
Mining Sector ◽  
Energy Carriers ◽  
Hard Coal Mining ◽  
Adverse Influence ◽  
Other World

Abstract The actual situation of hard coal mining in Poland has been presented. In particular, these factors, which have impact on the competiveness of mining sector were highlighted and need of its improving has been stressed. Outlining present situation of hard coal mining an attention was paid to its specific threats. The primary analytical material is based on the results of questionnaire conducted among 92 specialists and experts from the mining sector. The questions were related to chances and threats for development of hard coal mining in Poland. The factors determining them were grouped in such domains as economy, technology, geology, social and law aspects. Moreover, the special attention was paid to the problem of increasing and high costs of coal production which constitute significant threat for the financial and economic situation of the mining enterprises. Also the adverse influence of these high cost on the competitiveness of Polish hard coal with other world producers and with other energy carriers was emphasized. The conclusions summarize the achieved results of analysis.

ENVIRONMENTAL IMPACT OF COAL MINING

2020 ◽  
Author(s):  
Наталья Алексеевна Бойко ◽  
Наталья Владимировна Ромашева
Keyword(s):  
Environmental Impact ◽  
Organizational Structure ◽  
Coal Mining ◽  
Negative Impact ◽  
Coal Industry ◽  
Coal Production ◽  
Atmospheric Air

Представлена характеристика угольной отрасли России по таким направлениям как организационная структура, объем и регионы добычи, потребители угля. Выявлены положительные тенденции, определены проблемы в развитии угольной промышленности. Исследованы негативное воздействие угольного производство на такие компоненты окружающей среды, как атмосферный воздух, водные ресурсы, земная поверхность. The characteristic of the Russian coal industry in such areas as the organizational structure, volume and regions of production, coal consumers has been presented. Positive trends and problems in the development of the coal industry have been identified. The negative impact of coal production on environmental components such as atmospheric air, water, the earth’s surface has been investigated.

scholarly journals Dynamic characteristics and fractal representations of crack propagation of rock with different fissures under multiple impact loadings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bing Sun ◽  
Shun Liu ◽  
Sheng Zeng ◽  
Shanyong Wang ◽  
Shaoping Wang
Keyword(s):  
Fractal Dimension ◽  
Crack Propagation ◽  
Crack Growth ◽  
Impact Test ◽  
Fractal Theory ◽  
Dynamic Change ◽  
Fractal Dimensions ◽  
Peak Stress ◽  
Dynamic Mechanical Properties ◽  
Gravitational Potential Energy

AbstractTo investigate the influence of the fissure morphology on the dynamic mechanical properties of the rock and the crack propagation, a drop hammer impact test device was used to conduct impact failure tests on sandstones with different fissure numbers and fissure dips, simultaneously recorded the crack growth after each impact. The box fractal dimension is used to quantitatively analyze the dynamic change in the sandstone cracks and a fractal model of crack growth over time is established based on fractal theory. The results demonstrate that under impact test conditions of the same mass and different heights, the energy absorbed by sandstone accounts for about 26.7% of the gravitational potential energy. But at the same height and different mass, the energy absorbed by the sandstone accounts for about 68.6% of the total energy. As the fissure dip increases and the number of fissures increases, the dynamic peak stress and dynamic elastic modulus of the fractured sandstone gradually decrease. The fractal dimensions of crack evolution tend to increase with time as a whole and assume as a parabolic. Except for one fissure, 60° and 90° specimens, with the extension of time, the increase rate of fractal dimension is decreasing correspondingly.

scholarly journals Effect of Hydrophobic Silica Nanochannel Structure on the Running Speed of a Colloidal Damper

2021 ◽  
Vol 11 (15) ◽  
pp. 6808
Author(s):  
Gengbiao Chen ◽  
Zhiwen Liu
Keyword(s):  
Fractal Dimension ◽  
Silica Gel ◽  
Fractal Theory ◽  
Percolation Model ◽  
Silica Gels ◽  
Practical Significance ◽  
Running Speed ◽  
Fractal Percolation ◽  
Micropore Structure ◽  
Hydrophobic Silica

A colloidal damper (CD) can dissipate a significant amount of vibrations and impact energy owing to the interface power that is generated when it is used. It is of great practical significance to study the influence of the nanochannel structure of hydrophobic silica gel in the CD damping medium on the running speed of the CD. The fractal theory was applied to observe the characteristics of the micropore structure of the hydrophobic silica gel by scanning electron microscopy (SEM), the primary particles were selected to carry out fractal analysis, and the two-dimensional fractal dimension of the pore area and the tortuous fractal dimension of the hydrophobic silica gel pore structure were calculated. The fractal percolation model of water in hydrophobic silica nanochannels based on the slip theory could thus be obtained. This model revealed the relationship between the micropore structure parameters of the silica gel and the running speed of the CD. The CD running speed increases with the addition of grafted molecules and the reduction in pore size of the silica gel particles. Continuous loading velocity testing of the CD loaded with hydrophobic silica gels with different pore structures was conducted. By comparing the experimental results with the calculation results of the fractal percolation model, it was determined that the fractal percolation model can better characterize the change trend of the CD running velocity for the first loading, but the fractal dimension was changed from the second loading, caused by the small amount of water retained in the nanochannel, leading to the failure of fractal characterization.

scholarly journals Scale Characteristics and Optimization of Park Green Space in Megacities Based on the Fractal Measurement Model: A Case Study of Beijing, Shanghai, Guangzhou, and Shenzhen

2021 ◽  
Vol 13 (15) ◽  
pp. 8554
Author(s):  
Zhen Li ◽  
Wanmin Zhao ◽  
Miaoyao Nie
Keyword(s):  
Fractal Dimension ◽  
Evaluation System ◽  
Goodness Of Fit ◽  
Green Space ◽  
Fractal Theory ◽  
Measurement Model ◽  
Scale Structure ◽  
Qualitative Description ◽  
Urban Spatial Structure ◽  
Factors Affecting

This paper applies fractal theory to research of green space in megacity parks due to the lack of a sufficient qualitative description of the scale structure of park green space, a quantifiable evaluation system, and operable planning methods in traditional studies. Taking Beijing, Shanghai, Guangzhou, and Shenzhen as examples, GIS spatial analysis technology and the Zipf model are used to calculate the fractal dimension (q), the goodness of fit (R2), and the degree of difference (C) to deeply interpret the connotation of indicators and conduct a comparative analysis between cities to reveal fractal characteristics and laws. The research results show that (1) the fractal dimension is related to the complexity of the park green space system; (2) the fractal dimension characterizes the hierarchical iteration of the park green space to a certain extent and reflects the internal order of the scale distribution; (3) the scale distribution of green space in megacity parks deviates from the ideal pyramid configuration; and (4) there are various factors affecting the scale structure of park green space, such as natural base conditions, urban spatial structure, and the continuation of historical genes working together. On this basis, a series of targeted optimization strategies are proposed.

Strategies for follow-up care and utilisation of closing and flooding in European hard coal mining areas

2012 ◽  
Vol 89 ◽  
pp. 51-61 ◽  
Author(s):  
C. Klinger ◽  
A. Charmoille ◽  
J. Bueno ◽  
G. Gzyl ◽  
B. Garzon Súcar
Keyword(s):  
Coal Mining ◽  
Hard Coal ◽  
Mining Areas ◽  
Follow Up Care ◽  
Hard Coal Mining
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