Article
Engineering, Geological
Ang Liu, Shimin Liu, Kaiwen Xia, Peng Liu, Yun Yang, Gang Wang
Summary: Matrix shrinkage/swelling induced by gas sorption plays a crucial role in coalbed methane reservoir stress depletion and gas transport enhancement. This study used a sorption and matrix shrinkage system to measure the gas sorption capacity and 3-D anisotropic swelling/shrinkage strains simultaneously. The high heterogeneity and anisotropy of coals were confirmed using imaging techniques, and the principal strains were computed through a proposed strain transformation model.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Mathematics, Interdisciplinary Applications
Gaofeng Liu, Zhen Zhang, Yunxing Cao, Xiaoming Wang, Huan Liu, Baolin Li, Nian Si, Wenbo Guan
Summary: In this work, an analogical method for estimating the fractal dimension of three-dimensional fracture tortuosity (3D-FT) was proposed. A comparison and error analysis of analogical and rigorous methods on fractal dimension for 3D-FT were conducted. The proposed analogical method, which calculates the fractal dimension (DT-R) of 3D-FT as a function of average tortuosity (t(av)) and average fracture length (L-av), demonstrates high accuracy and good consistency with the rigorous method (DT-R).
FRACTALS-COMPLEX GEOMETRY PATTERNS AND SCALING IN NATURE AND SOCIETY
(2023)
Article
Green & Sustainable Science & Technology
Carolina Bilibio, Stefanie Retz, Christian Schellert, Oliver Hensel
Summary: Mining is a crucial economic activity that generates significant waste, such as in the potash industry. An experiment was conducted to assess the drainage quality of technosols used for an evapotranspiration cover on potash tailings, revealing changes in pH, electrical conductivity, chemical element concentrations, and ionic loads.
JOURNAL OF CLEANER PRODUCTION
(2021)
Article
Mathematics, Interdisciplinary Applications
Chunwei Ling, Bin Liu, Cun Zhang, Teng Teng, Kangning Zhang, Bo Sun, Jinlong Zhou
Summary: This study investigates the evolution features of ground fissures in large mining height working faces and shallow buried coal seams through field observation data, similar simulation, and numerical simulations. The results indicate that the weathered rock layer inhibits fracture growth caused by coal mining, and the movement deformation region of the ground fissure can be described by three characteristic zones.
FRACTAL AND FRACTIONAL
(2023)
Article
Thermodynamics
Mingqiu Wu, Haitao Li, Liang Wang, Xinlei Yang, Chongyang Dai, Ning Yang, Jie Li, Yu Wang, Minggao Yu
Summary: An infrared rapid heating apparatus was used to heat coal samples at different temperatures, and high-precision micro-CT scanning was employed to establish a three-dimensional pore-fracture structure model. The results showed that the number of pore fractures and throats reached a maximum at 200 degrees C, and the pore and fracture structures in coal tended to develop more with increasing temperature. Moreover, the study found that the fractal dimension and porosity of coal increased significantly with temperature, and the interconnection between pores and fissures caused by temperature increase led to an increase in connectivity and permeability.
Article
Mathematics, Interdisciplinary Applications
Zhen Zhang, Gaofeng Liu, Xiaoming Wang, Baolin Li, Huan Liu
Summary: This paper proposes a method for fractal characterization of fracture volume in coal based on CT scanning experiment. It derives the relation among fractal dimension D, fracture volume, and length scale. The results demonstrate that fracture volume comprehensively embodies the height, length, and aperture of fracture. Therefore, further research on establishing an analytical equation based on D for fluid transport characteristics in porous media is worth exploring.
FRACTALS-COMPLEX GEOMETRY PATTERNS AND SCALING IN NATURE AND SOCIETY
(2022)
Article
Energy & Fuels
Xuechang Chen, Gang Wang, Hao Chen, Shibin Wang
Summary: This study focuses on the influence of fractures with different shapes on seepage during coal seam water injection. A structural model containing five types of fractures was created based on CT scan, 3D reconstruction, and artificial fracture. The relationships between fracture parameters and shape factor were calculated using the Navier-Stokes equation. The research results provide theoretical guidance for coal seam water injection engineering.
Article
Chemistry, Applied
Xinyang Men, Shu Tao, Zhenxing Liu, Wenguang Tian, Shida Chen
Summary: The gas seepage characteristics of coal matrix samples with different permeabilities were studied through series and parallel seepage simulation experiments. The results show that there are different gas supply capacities and seepage channels in areas with different permeabilities.
FUEL PROCESSING TECHNOLOGY
(2021)
Article
Mathematics, Interdisciplinary Applications
Zhen Zhang, Gaofeng Liu, Xiaoming Wang, Mingshi Wang, Baolin Li, Huan Liu
Summary: This paper proposed a method for fractal characterization of DT3 in coal fractures using CT scanning experiment. The method was deduced in detail and the values of DT3 for four coal samples were calculated. The proposed method showed rationality and accuracy in estimating DT3 by fitting the relation of DT3 with fractal dimension and fracture porosity. The results suggest that DT3 can comprehensively characterize the fractal characteristics of fractures in 3D space.
FRACTALS-COMPLEX GEOMETRY PATTERNS AND SCALING IN NATURE AND SOCIETY
(2023)
Article
Engineering, Chemical
Qingao Zhu, Liming Yin, Qiming Huang, Enmao Wang, Zhiguo Hou
Summary: In this study, the pressure changes and pulverized coal blocking characteristics were experimentally studied using deionized water and three surfactant solutions (1227, SDS, and TX-100). A device capable of visualizing propped fractures was established, and simulation experiments were conducted. The results showed that surfactant solutions can lower the injection pressure, and different surfactants have different effects at different injection flow rates. This study provides theoretical support for improving coal seam permeability and dust prevention effect of coal seam water injection.
Article
Mathematics, Interdisciplinary Applications
Runsheng Lv, Yuchen Zhu, Xinyu Ma, Xiaoming Ni, Jiangang Ren
Summary: This paper applies fractal theory to study the structure of coal pores and establishes a dynamic prediction mechanical model of coal permeability based on pore heterogeneity. The experimental results show that the permeability change in methane-bearing coal is closely related to coal pore deformation and is affected by changes in the effective stress coefficient. The highly accurate fractal Langmuir model is verified and can be used for coal reservoir permeability prediction.
FRACTAL AND FRACTIONAL
(2022)
Article
Thermodynamics
Qiang Guo, Jing-Feng LI, Zhi-Guo Cao, Jun -Ting Guo
Summary: Taking Lingxin Coal Mine as the research object, a combination of physical experiment and numerical simulation analysis was used to study the mining failure of overlying strata and the development of surrounding rock cracks in goaf. The results show that when the underground coal seam mining is not sufficient, the overburden separation is developed, the connected pore area of the overburden failure accounts for about 20% of the total mining area. When the underground coal seam is fully mined, the overburden failure is severe, the overburden failure cracks are interconnected, and the connected pore area increases significantly.
Article
Engineering, Geological
Zhen Liu, Wenzhi Yang, He Yang, Bo Cheng, Peng Hu
Summary: This paper investigates the change law of fracture structure in coal under different stress conditions using nuclear magnetic resonance (NMR) and two characterization parameters. The results show that fractal dimensions can accurately quantify the change law of coal fracture structure and are applicable in real mechanical environments during coal seam water injection.
GEOTECHNICAL AND GEOLOGICAL ENGINEERING
(2022)
Article
Geosciences, Multidisciplinary
Chenghang Fu, Heping Xie, Mingzhong Gao, Fei Wang, Jing Xie, Junjun Liu, Bengao Yang, Ruifeng Tang
Summary: The study revealed that coal in the fracture zone is most strongly affected by roadway excavation, forming effective permeability; coal in the disturbance zone is less affected and forms effective permeability after peak strength; coal in the original rock stress zone is only influenced by coal mining, with the lowest permeability.
GEOMATICS NATURAL HAZARDS & RISK
(2021)
Article
Mathematics, Interdisciplinary Applications
Zhen Liu, Wenzhi Yang, He Yang, Peng Hu, Shuangyue Wang
Summary: This study focused on the water seepage characteristics in coal fracture networks using fractal geometry theory. A seepage model was established and validated through experiments, showing that the influence of fracture diameter ratio on permeability was significant. Overall, the study provides a theoretical basis for understanding the seepage law of high-pressure water in coal bodies and the relationship between permeability and environmental parameters.
FRACTALS-COMPLEX GEOMETRY PATTERNS AND SCALING IN NATURE AND SOCIETY
(2021)
Article
Thermodynamics
Zheqiang Jia, Li Ren, Qiangying Liu, Yuan Peng, Duo Xu, Ersheng Zha
Article
Energy & Fuels
Zetian Zhang, Ru Zhang, Heping Xie, Mingzhong Gao, Ersheng Zha, Zheqiang Jia
JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING
(2017)
Article
Energy & Fuels
Ersheng Zha, Ru Zhang, Zetian Zhang, Ting Ai, Li Ren, Zhaopeng Zhang, Yang Liu, Chendi Lou
Article
Geosciences, Multidisciplinary
Ersheng Zha, Shiyong Wu, Zetian Zhang, Ru Zhang, Man Wang, Jifang Zhou, Zhaopeng Zhang, Zheqiang Jia
ARABIAN JOURNAL OF GEOSCIENCES
(2020)
Article
Energy & Fuels
Anlin Zhang, Ru Zhang, Mingzhong Gao, Zetian Zhang, Zheqiang Jia, Zhaopeng Zhang, Ersheng Zha
Article
Engineering, Geological
Ersheng Zha, Zetian Zhang, Ru Zhang, Shiyong Wu, Cunbao Li, Li Ren, Mingzhong Gao, Jifang Zhou
Summary: This study systematically proposed a laboratory simulation method to test the stability of deep caverns after excavation disturbance, revealing a significant decrease in long-term rock strength considering excavation disturbance. The results also showed that with an increase in stress level, the transient strain of the deep rock increases nearly linearly, while the axial creep strain rate increases exponentially, with distinctive characteristics observed in different stages through AE monitoring.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2021)
Article
Engineering, Geological
Kun Xiao, Ru Zhang, Jing Xie, Li Ren, Mingzhong Gao, Zetian Zhang, Chendi Lou, Ting Ai, Ersheng Zha
Summary: This study investigates the impact of fracture characteristics on the mechanical and hydraulic properties of rock mass. By simplifying fractures as non-similar ellipses, a multifactor coupling stereological relationship of the sampling trace length distribution is established. The distribution expressions of the major axis and axial ratio of the elliptical fractures are obtained, and a method is proposed to solve the probability density function of the characteristic size of the elliptical fractures. The applicability of the proposed method is verified through a Monte Carlo statistical simulation.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Thermodynamics
Ersheng Zha, Ru Zhang, Zetian Zhang, Li Ren, Wenju Zhang, Zheqiang Jia, Yang Liu