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Full-Text Articles in Physical Sciences and Mathematics
Response Mechanism Characteristics Of Mining-Induced Fault Activation, Sun Wenbin, Hao Jianbang, Dai Xianzheng, Kong Lingjun
Response Mechanism Characteristics Of Mining-Induced Fault Activation, Sun Wenbin, Hao Jianbang, Dai Xianzheng, Kong Lingjun
Coal Geology & Exploration
In the process of coal mining, mining-induced stress perturbation is a key factor leading to fault activation, which is a primary challenge faced by safe coal mining. Fault activation is prone to induce geological disasters such as rock bursts and floor water inrushes of coal mines. Furthermore, it poses a serious threat to mining safety. Using the Flac3D software for numerical simulations and similar material simulation experiments, this study established a model for faults’ stress-displacement responses under coal mining to analyze the mechanisms behind the evolution of fault structure zones in the process of coal mining. Key findings are …
Three-Dimensional Forward Modeling Using The Transient Electromagnetic Method Under Complex Terrains And The Analysis Of Terrain Effects, Qu Shaobo, Zhu Jiao, Jiang Zhihai, Li Maofei, He Zhilong
Three-Dimensional Forward Modeling Using The Transient Electromagnetic Method Under Complex Terrains And The Analysis Of Terrain Effects, Qu Shaobo, Zhu Jiao, Jiang Zhihai, Li Maofei, He Zhilong
Coal Geology & Exploration
The ground-based transient electromagnetic method (TEM), with unique advantages, has been extensively applied for hydrogeological exploration in coal mines. However, in field exploration, complex terrains tend to cause variations in geometric shapes of transmitting sources and deviations in signals received, reducing exploration accuracy. Hence, by integrating theoretical analysis and numerical simulations with the analysis of actual terrain data, this study systematically investigated the response characteristics of electrical- and magnetic-source TEM fields under complex terrains. Using the vector finite-element electromagnetic forward modeling technique based on second-order backward Euler discretization, this study delved into the laws of influence of peak and valley …
Numerical Simulation On Influence Of Skin Effect On Groundwater Flow Velocity In Wellbore, Wang Qihang, Li Xu, Guo Qiang, Kuai Dawei
Numerical Simulation On Influence Of Skin Effect On Groundwater Flow Velocity In Wellbore, Wang Qihang, Li Xu, Guo Qiang, Kuai Dawei
Coal Geology & Exploration
Groundwater flow velocity in wellbore is usually measured by single-well tracking tests or Aqua Vision flow velocity and direction meters to calculate the groundwater flow velocity in the aquifer. Due to the impact of the skin structure, the groundwater flow field near the wellbore changes, causing a difference between the flow velocity in the wellbore and that in the aquifer. In order to investigate the influence of the skin effect on the groundwater flow velocity in the wellbore, a numerical model of groundwater flow that considers the skin effect was established using the COMSOL Multiphysics software. On this basis, the …
Sensitivity Analysis Of Development Parameters On The Production Temperature Of Karst Geothermal Reservoirs: A Case Study Of The Qingfeng Area In Henan, China, Han Yun, Li Kewen, He Jifu, Wang Xinwei, Gao Nan’An
Sensitivity Analysis Of Development Parameters On The Production Temperature Of Karst Geothermal Reservoirs: A Case Study Of The Qingfeng Area In Henan, China, Han Yun, Li Kewen, He Jifu, Wang Xinwei, Gao Nan’An
Coal Geology & Exploration
The temperature of produced geothermal water serves as a pivotal indicator influencing the efficiency of geothermal energy utilization, with a higher temperature corresponding to more effective geothermal reservoir exploitation. For karst geothermal reservoirs, recognized as a significant type of geothermal reservoir, the temperature of produced geothermal water is influenced by reservoir parameters. Focusing on the Ordovician karst geothermal reservoirs in the Qingfeng area, Henan Province, this study established a geological model of the reservoirs, followed by numerical simulations based on thermal flow and well-reservoir coupling using the data of seven geothermal wells. The purpose is to explore the effects of …
Influencing Factor Analysis And Optimization Of Heat Extraction Performance Of Moderately Deep Coaxial Borehole Heat Exchangers In Northern Shaanxi, China, Zou Haijiang, Li Yongpeng, Zhang Lin, Hui Peng, Liu Houning, Shen Fang, Wang Fenghao
Influencing Factor Analysis And Optimization Of Heat Extraction Performance Of Moderately Deep Coaxial Borehole Heat Exchangers In Northern Shaanxi, China, Zou Haijiang, Li Yongpeng, Zhang Lin, Hui Peng, Liu Houning, Shen Fang, Wang Fenghao
Coal Geology & Exploration
The geothermal heating technology utilizing moderately deep coaxial borehole heat exchangers (MDCBHEs) has emerged and found extensive applications in urban heating in northern China. Despite abundant geothermal resources, northern Shaanxi exhibits slightly low geothermal gradients and distinct thermophysical properties of rocks and soils. Therefore, geological parameters influence the heat transfer performance of MDCBHEs in this area. Using OpenGeoSys, an open-source numerical simulation platform, this study established a three-dimensional calculation model for heat transfer between a MDCBHE and surrounding strata. Based on typical geological parameters in northern Shaanxi, the study investigated the influence of various design parameters on the heat transfer …
Heating Experiments Of A Solar-Assisted Heat Pump And Thermal Equilibrium Simulations Of Geothermal Fields, Jia Zilong, Zheng Jia, Zhang Yaobin, Chen Ke, Liu Aihua, Li Juan
Heating Experiments Of A Solar-Assisted Heat Pump And Thermal Equilibrium Simulations Of Geothermal Fields, Jia Zilong, Zheng Jia, Zhang Yaobin, Chen Ke, Liu Aihua, Li Juan
Coal Geology & Exploration
This study aims to explore technologies required for clean energy heating by means of multi-energy complementation, with the purpose of meeting the demand for clean heating in decentralized buildings in Beijing's villages and towns. To this end, this study built a solar-ground source heat pump (SGHP) compound system in a rural area of Beijing. Then, it carried out heating experiments of the solar-assisted heat pump system and thermal equilibrium simulations of geothermal fields using the COMSOL software. The results are as follows: (1) Compared to a single SGHP system, the solar-assisted heat pump scheme increased the outlet water temperature on …
Evaluating The Exploitation And Utilization Prospects Of Hot Dry Rock In Bohai Bay Basin: Understanding Based On Numerical Simulations For Exploitation Optimization, Jiang Xiaoxue, Zhu Chuanqing, Ding Rui, Xie Fang, Qiu Nansheng
Evaluating The Exploitation And Utilization Prospects Of Hot Dry Rock In Bohai Bay Basin: Understanding Based On Numerical Simulations For Exploitation Optimization, Jiang Xiaoxue, Zhu Chuanqing, Ding Rui, Xie Fang, Qiu Nansheng
Coal Geology & Exploration
The Bohai Bay Basin, characterized by high terrestrial heat flow, formation temperatures average of 175℃ at a depth of 5000 m, and reservoirs with lithologies dominated by low-porosity and low-permeability metamorphic and igneous rocks, meets the requirements for the formation of hot dry rock (HDR) resources. Based on geothermal parameters such as terrestrial heat flow, rock thermal conductivity, and heat production rate, this study established a three-dimensional HDR exploitation model with thermo-hydro coupling using the COMSOL software. Furthermore, this study analyzed the effects of spacing between production and reinjection wells, reinjection and production rates, and well arrangement mode on the …
Effects Of Fracture Distribution On Heat Extraction Through Co2-Egs, Zhou Qing, Liao Jianxing, Xu Bin, Yao Liang, Zhou Haoyu, Zhao Quan
Effects Of Fracture Distribution On Heat Extraction Through Co2-Egs, Zhou Qing, Liao Jianxing, Xu Bin, Yao Liang, Zhou Haoyu, Zhao Quan
Coal Geology & Exploration
Geothermal energy, a promising source of renewable energy, has attracted considerable attention. In deep geothermal reservoirs, complex fracture networks formed by artificial stimulation provide predominant channels for heat extraction. Therefore, the spatial distribution of fractures directly affects the heat extraction efficiency. This study aims to explore the effects of different spatial distributions of fractures on the heat recovery performance. Based on the fracture network following a power-law distribution, this study systematically investigated the effects of the fracture network with different values of fracture length index (a) and density (β) on the heat recovery performance of a …
Dual-Frequency Transmission Radio Wave-Based Exploration Method And Its Application, Fu Xianjie, Hu Ze'an, Wu Rongxin, Li Peng
Dual-Frequency Transmission Radio Wave-Based Exploration Method And Its Application, Fu Xianjie, Hu Ze'an, Wu Rongxin, Li Peng
Coal Geology & Exploration
Coal seams can act as the guided wave layers of high-frequency electromagnetic waves, and radio wave perspective technology can be used to detect geological structures within coal seams of a working face. Presently, radio wave perspective methods usually use a single frequency, leading to some problems such as improper frequency selection and limited detection accuracy in the exploration of mining faces. In response, this study developed a dual-frequency transmission radio wave-based exploration method. Based on theoretical analysis, as well as the field strength of dual-frequency perspective and attenuation coefficient, this study derived the calculation formula for the absorption factor γ …
Numerical Simulations Of Enhancing Permeability And Gas Extraction Of Thick Coal Seams Through Static Fracturing, Wang Xinfeng, Liu Wengang, Wang Long, Wei Youyu, Zhang Qiao
Numerical Simulations Of Enhancing Permeability And Gas Extraction Of Thick Coal Seams Through Static Fracturing, Wang Xinfeng, Liu Wengang, Wang Long, Wei Youyu, Zhang Qiao
Coal Geology & Exploration
This study seeks to improve the underground operation efficiency and optimize the borehole arrangement parameters for static fracturing of coal seams. To this end, this study conducted tests in the belt roadway of the No. 12316 fully mechanized mining face in the Wangjialing Coal Mine, China Coal Huajin Group. By combining the equations for coal seams’ deformation and failure, gas diffusion and seepage, and coal seams’ permeability evolution, this study constructed a model of the damage and permeability evolution of coal seams. Based on the numerical simulations of the process of static fracturing and permeability enhancement of coals, as well …
Numerical Simulations Of The Effects Of Bedding Planes On Hydraulic Fracture Propagation Law In Oil Shale, Li Yanwei, Zhu Chaofan, Zeng Yijian, Shui Haoche, Fan Cunhan, Guo Wei
Numerical Simulations Of The Effects Of Bedding Planes On Hydraulic Fracture Propagation Law In Oil Shale, Li Yanwei, Zhu Chaofan, Zeng Yijian, Shui Haoche, Fan Cunhan, Guo Wei
Coal Geology & Exploration
Hydraulic fracturing serves as a major technical means for the exploitation of oil shale reservoirs presently, and the hydraulic fracture morphology in oil shales is primarily affected by differences in the characteristics of bedding planes. However, current studies mostly focus on the influence of the developmental degree of bedding planes on fracture propagation, overlooking the effects of the bedding plane thickness itself on hydraulic fracture propagation. This study delves into the oil shale in the Xunyi area, Ordos Basin. Based on the theory of linear elastic fracture mechanics, this study developed a stress-damage-seepage model of hydraulic fracture propagation. Using the …
A Method For Evaluating Aquiclude Stability In The Water Conservation-Based Mining Of Shallowly Buried Coal Seams In Ecologically Vulnerable Areas In Northwest China, Li Heng, He Tao, Guo Bin
A Method For Evaluating Aquiclude Stability In The Water Conservation-Based Mining Of Shallowly Buried Coal Seams In Ecologically Vulnerable Areas In Northwest China, Li Heng, He Tao, Guo Bin
Coal Geology & Exploration
Water conservation and coal mining are both critical to Northwest China. Water conservation-based coal mining is an important technology for the coordinated development of coal and water resources in this region. In this technology, the evaluation of aquiclude stability is critical. Due to the shallow depth of coal seams, intense topographic cutting, and complex changes in near-surface aquifers in the ecologically vulnerable areas in Northwest China, there exist large errors between traditional methods for aquiclude evaluation and the actual hydrological observations in these areas. To address this challenge, this study develops using the 3D geological modelling combined with numerical simulation …
Water Inrush Mechanism Of Coal Mine Shaft Fracture Under Fluid-Solid Coupling, Xue Weipei, Shen Lei, Yao Zhishu, Cheng Hua, Rong Chuanxin
Water Inrush Mechanism Of Coal Mine Shaft Fracture Under Fluid-Solid Coupling, Xue Weipei, Shen Lei, Yao Zhishu, Cheng Hua, Rong Chuanxin
Coal Geology & Exploration
The occurrence of coal mine shaft fractures and water inrush accidents is alarmingly frequent, endangering the lives of underground personnel and compromising mine safety. To comprehend the influence of confined groundwater in the process of shaft fracture and the formation mechanism of water inrush channels, a model test was devised using similarity theory and coupled fluid-solid numerical simulation technology. The findings reveal that direct contact between the shaft lining and pressurized water hinders the development of load-bearing and deformation capacities. This is specifically evidenced by the premature appearance of the yield point, a reduction in peak strength and strain, and …
Numerical Simulations And Wavefield Analysis Of In-Seam Wave Advance Detection In Viscoelastic Media, He Dixiu, Ji Guangzhong, Jiao Wenjie, Zhang Yawei, Yu Kun
Numerical Simulations And Wavefield Analysis Of In-Seam Wave Advance Detection In Viscoelastic Media, He Dixiu, Ji Guangzhong, Jiao Wenjie, Zhang Yawei, Yu Kun
Coal Geology & Exploration
In-seam waves are commonly applied to the advance detection of hidden faults in front of mining faces. However, coal seams, which have viscoelasticity actually, imposing absorptive and attenuation effects on in-seam waves. To investigate the wave field characteristics and propagation patterns of in-seam waves in viscoelastic coal seam media, this study built a three-dimensional geological model of coal measures with faults based on Kelvin-Voigt’s first-order velocity-stress equation. Using this equation, three-dimensional finite-difference numerical simulation was carried out. The results indicate that (1) for reflected in-seam waves in viscoelastic media, which exhibit high energy attenuation, their propagation and attenuation characteristics are …
Wear Law And Design Of Assembling Diamond Bit Based On Finite Element Analysis, Yang Zhan, Tan Songcheng, Yang Kaihua, Fang Xiaohong
Wear Law And Design Of Assembling Diamond Bit Based On Finite Element Analysis, Yang Zhan, Tan Songcheng, Yang Kaihua, Fang Xiaohong
Coal Geology & Exploration
In addition to coring drilling, full (non-coring) drilling also occupies a large proportion in the energy exploration and development. Non-coring drilling can reduce the high time cost of lifting and lowering work required for coring, thereby increasing the net drilling time, improving the drilling efficiency and reducing the drilling costs. The traditional non-coring drill bits are prone to uneven wear on the bit surface during the drilling process. To identify and improve this law of uneven wear, it was herein proposed to use the assembling non-coring bit to improve the eccentric wear of bit. For this reason, numerical simulation analysis …
Continuous And Discontinuous Numerical Simulation Of The Rock Breaking Process Of Pdc Drill Bit Under Composite Impact, Qin Chengshuai, Sun Hongbin, Li Liping, Liu Xuegang, Liu Zhihui, Feng Chun, Sun Zizheng
Continuous And Discontinuous Numerical Simulation Of The Rock Breaking Process Of Pdc Drill Bit Under Composite Impact, Qin Chengshuai, Sun Hongbin, Li Liping, Liu Xuegang, Liu Zhihui, Feng Chun, Sun Zizheng
Coal Geology & Exploration
Composite impact drilling is a novel rock-breaking technique that combines both axial and torsional impacts. To address the issues of complex failure mechanisms and unclear rock-breaking mechanisms under the axial-torsional impacts on rock by Polycrystalline Diamond Compact (PDC) drill bits, a FEM-DEM rock model based on shared nodes was established using the Continuous Discontinuous Element Method (CDEM), and the rationality of this computational model was verified through laboratory uniaxial compression experiments. Besides, a composite impact motion model for single drill bit was built through the secondary development of JavaScript, and the composite impact rock-breaking process of single PDC drill bit …
Propagation Of Hydraulic Fractures In Thin Interbedded Tight Sandstones, Yang Fan, Mei Wenbo, Li Liang, Sun Zening, An Qi, Yang Qi, Lu Meiquan, Yang Ruiyue
Propagation Of Hydraulic Fractures In Thin Interbedded Tight Sandstones, Yang Fan, Mei Wenbo, Li Liang, Sun Zening, An Qi, Yang Qi, Lu Meiquan, Yang Ruiyue
Coal Geology & Exploration
Thin interbedded tight sandstone reservoirs are characterized by strong vertical heterogeneity due to the superimposed pattern of the deposited sandstones and mudstones. As a result, hydraulic fractures are difficult to propagate vertically to effectively connect the reservoirs. Given this, ascertaining the vertical propagation patterns of hydraulic fractures in thin interbeds is of great significance for the development of thin interbedded tight sandstones. With the thin interbedded tight sandstone reservoirs of the lower Shihezi Formation in the Linxing block, Ordos Basin as a case study, this study built the fracture propagation model of these sandstones. Accordingly, it analyzed the effects of …
Research On Stability Of Rock Mass And +30 Level Surface Construction Works When Re-Exploiting The Seam H10 At Mong Duong Coal Mine, Vietnam, Tien Trung Vu, Doan Viet Dao
Research On Stability Of Rock Mass And +30 Level Surface Construction Works When Re-Exploiting The Seam H10 At Mong Duong Coal Mine, Vietnam, Tien Trung Vu, Doan Viet Dao
Journal of Sustainable Mining
The re-exploitation of coal seams located near the ground is one of the solutions to increase output, reduce mining investment costs, and avoid wasting coal resources. The re-exploitation of coal seams will also cause instability of the surrounding rock mass and may affect surface construction works. Through the process of re-exploiting the longwall in seam H10 at Mong Duong Coal Mine, the authors have studied and evaluated the stability of the rock mass and +30 level surface works (including fan station and gateroad). To achieve the results in this study, the numerical simulation model method and the analytical method were …
Slip Resistance Effect Of Pile-Soil Interface Inclination Angle And Moisture Content On The Anti-Sliding Pile, Li Huaixin, Yan Changgen, Lin Bin, Shi Yuling
Slip Resistance Effect Of Pile-Soil Interface Inclination Angle And Moisture Content On The Anti-Sliding Pile, Li Huaixin, Yan Changgen, Lin Bin, Shi Yuling
Coal Geology & Exploration
To study the slip resistance effect of pile-soil interface with different interface inclination angle and moisture content, the variability of damage modes and shear strengths of assemblies with variable inclination angles under the different conditions of interface inclination angles and water content were compared based on the triaxial unconsolidated undrained test at first. Then, the slip resistance effects of the pile-soil interface with different interface inclination angles and moisture contents were compared by numerical simulation, with consideration to the shear strength parameter of laboratory test. Meanwhile, the critical moisture content wmax was determined based on the plastic deformation theory. …
Coal And Gas Outburst Mechanism: Research Progress And Prospect In China Over The Past 70 Years, Zhang Chaolin, Wang Peizhong, Wang Enyuan, Xu Jiang, Li Zhonghui, Liu Xiaofei, Peng Shoujian
Coal And Gas Outburst Mechanism: Research Progress And Prospect In China Over The Past 70 Years, Zhang Chaolin, Wang Peizhong, Wang Enyuan, Xu Jiang, Li Zhonghui, Liu Xiaofei, Peng Shoujian
Coal Geology & Exploration
The effective prevention and control of coal and gas outbursts have always been a challenge for safe coal mining in China, and their prerequisite and basis are in-depth research on the coal and gas outburst mechanism. This study expatiated the efforts and achievements of China made in research on the coal and gas outburst mechanism over the past 70 years, which can be divided into four stages, namely active exploration (1955‒1977), the establishment of the theoretical foundation (1978‒2002), rapid development (2003‒2015), and stable development (2016 to the present). This study explored the hot research topics and frontier trends of the …
Influence Of Thick Sandstone On Development Of Overburden Mining Fissures In Northern Shaanxi Coal Mining Area Of Yellow River Basin And Suggestions On Water-Preserved Coal Mining, Wang Shuangming, Wei Jiangbo, Song Shijie, Wang Shengquan, Sun Tao
Influence Of Thick Sandstone On Development Of Overburden Mining Fissures In Northern Shaanxi Coal Mining Area Of Yellow River Basin And Suggestions On Water-Preserved Coal Mining, Wang Shuangming, Wei Jiangbo, Song Shijie, Wang Shengquan, Sun Tao
Coal Geology & Exploration
The change of geological conditions of coal seam roof overburden and the development of mining fissures caused by coal mining activities are the direct causes of damage to the key underground aquifers, and also the root causes of ecological environment degradation in the mining area. As a typical geological condition, the thick sandstone developed in the overburden structure of the coal seam roof has an important impact on the development law of mining fissures in the overburden. Therefore, the influence of the thickness and location of different thick sandstones on the development morphology and height of overburden mining fractures was …
Occurrence Law Of Coal Seam Gas Under Influence Of Normal Fault Zone In Coal Measures, Xiao Peng, Wu Mingchuan, Shuang Haiqing, Han Kai, Gao Zhen, Cheng Yueying
Occurrence Law Of Coal Seam Gas Under Influence Of Normal Fault Zone In Coal Measures, Xiao Peng, Wu Mingchuan, Shuang Haiqing, Han Kai, Gao Zhen, Cheng Yueying
Coal Geology & Exploration
The coal measure fault zone generated by the superimposition of the polytropic movement and multiple structure has important effects on the coal seam gas occurrence. The method of combining the geologic analysis, COMSOL Multiphysics numerical simulation and field data monitoring was adopted to analyze the interaction relations between the stress distribution characteristics and faults of the normal fault zone in the coal measure, study the coal seam permeability variation characteristics influenced by the normal fault zone in the coal measure, and simulate the gas migration status and concentration distribution condition after the formation of the normal fault zone. The coal …
Numerical Simulation Of The Influence Of Karst Structure On Heat Transfer Efficiency Of Buried Pipeline Group, Mu Xuan, Pei Peng, Zhou Xin, Tu Hongsheng
Numerical Simulation Of The Influence Of Karst Structure On Heat Transfer Efficiency Of Buried Pipeline Group, Mu Xuan, Pei Peng, Zhou Xin, Tu Hongsheng
Coal Geology & Exploration
The buried pipeline is the part where the rock mass heat pump system performs direct heat transfer with the ground. The water-bearing structure in the karst area is complex and diverse, which has a significant impact on the heat transfer and storage of the buried pipeline group. Herein, the heat transfer process of a group of 27 vertical buried pipelines in four geological structure types was simulated, including the non-karst structure, fractured karst structure, karst conduit structure and mixed karst structure. Meanwhile, comparison was made for the change of parameters, such as the temperature field in the rock mass, the …
Study Of Advance Elaborate Detection With Transient Electromagnetic Method For Mine With Closed Poor Boreholes, Huang Zhongzheng, Jiang Guoqing, Wang Jun, Cheng Jiulong, Ma Zhi, Tian Chuxiao, Xin Chengtao
Study Of Advance Elaborate Detection With Transient Electromagnetic Method For Mine With Closed Poor Boreholes, Huang Zhongzheng, Jiang Guoqing, Wang Jun, Cheng Jiulong, Ma Zhi, Tian Chuxiao, Xin Chengtao
Coal Geology & Exploration
Closed poor boreholes connect aquifers at some degree to form well concealed water diversion channels, which poses a water hazard threat on either tunneling or working bench recovery. In order to discuss the effectiveness of using the transient electromagnetic method in the advance detection of closed poor boreholes for the mine, the 3D geologic-geophysical model of the closed poor boreholes in front of the tunneling working bench was established based on the full-space transient electromagnetic theory to simulate and study the response characteristics of the full-space transient electromagnetic field in the influence area model of closed poor boreholes. As indicated …
Abnormal Response Characteristic Simulation During Transient Electromagnetic Detection In Mine Borehole, Zhang Jun
Coal Geology & Exploration
Conventional mine transient electromagnetic advance detection method is greatly influenced by the condition outside of the mine, which leads to the inaccurate location in anomalous body detection. In order to solve this problem, an advance detection method for measuring the three-component signals of the transient electromagnetic field in the down-hole borehole was proposed to carry out numerical simulation for the abnormal response characteristics from the different locations of the plane where the receiving coil is located and the different orientations of the anomalous body. The principle of borehole transient electromagnetic detection was analyzed, and the test design and construction design …
Failure Analysis Of Deep Coal Seam Floor Considering Strain Softening Of Surrounding Rock And Formation Contact In Goaf, Yin Shangxian, Meng Haopeng, Qian Shuangbin
Failure Analysis Of Deep Coal Seam Floor Considering Strain Softening Of Surrounding Rock And Formation Contact In Goaf, Yin Shangxian, Meng Haopeng, Qian Shuangbin
Coal Geology & Exploration
In order to study the failure mode of the floor in deep coal seam mining, we proposed a FLAC3D finite difference numerical method considering the strain softening of surrounding rock and the contact of goafs .Through the qualitative analysis of Rankine’s earth pressure theory, the failure of the deep coal seam floor is studied based on the measured water conducting fracture zone of the floor in working face 2023 of Linxi Mine. The results show that the mechanical state of surrounding rock after plastic failure can be described more accurately by using the strain-softening constitutive relationship instead of the …
Principle Of A Self-Protective Sealing Device For Mwd And Its Influencing Factors, Wang Yaoming, Ye Genfei, Zhao Yongzhe, Gao Ke, Liu Weiwei, Duan Huijun
Principle Of A Self-Protective Sealing Device For Mwd And Its Influencing Factors, Wang Yaoming, Ye Genfei, Zhao Yongzhe, Gao Ke, Liu Weiwei, Duan Huijun
Coal Geology & Exploration
For deeper drilling depth and longer service life of MWD, a self-protection sealing device for the MWD instrument is designed given the defects of the combined static sealing structure. The relationship between rubber airbag expansion displacement and air pressure was studied through static expansion numerical simulation. On this basis, the reasons for different results due to different model sizes were analyzed, and the factors causing the different simulation results of the self-protection sealing device were discussed. The four independent variables of airbag diameter, width, wall thickness and inner cavity width were determined and simulated to explore their relationship with the …
Characteristics Of Coal And Gas Outburst And Controlling Mechanism Of Stress Field In The Hanging Wall Of Normal Faults, Cao Yunxing, Zhang Haiyang, Zhang Zhen, Liu Gaofeng
Characteristics Of Coal And Gas Outburst And Controlling Mechanism Of Stress Field In The Hanging Wall Of Normal Faults, Cao Yunxing, Zhang Haiyang, Zhang Zhen, Liu Gaofeng
Coal Geology & Exploration
The fault zone is the main geological unit where coal and gas outbursts occur. Statistics of many coal and gas outbursts show that the number and intensity of the outbursts in the hanging wall are significantly greater than those in the foot wall for normal faults. However, there are few studies on the geological mechanism of this phenomenon, especially the variation of the in-situ stress field in the hanging wall of normal faults before and after mining, and its controlling mechanism of coal and gas outbursts that has not been completely demonstrated. In view of this, the normal fault DF …
Coupling Simulation Of Groundwater Dynamics And Solute Transfer In The Process Of Deep Reinjection Of Mine Water, Zhao Chunhu, Yang Jian, Wang Shidong, Zhou Jianjun, Xu Feng, Liu Ji
Coupling Simulation Of Groundwater Dynamics And Solute Transfer In The Process Of Deep Reinjection Of Mine Water, Zhao Chunhu, Yang Jian, Wang Shidong, Zhou Jianjun, Xu Feng, Liu Ji
Coal Geology & Exploration
The deep well reinjection of mine water is a main form of "transfer storage" treatment of mine water. According to the geological and mine water characteristics of the coal mine area in Ordos Basin, the paper puts forward the basis for selecting the target layer of mine water reinjection from the perspective of good matching between groundwater and mine water in the target layer of reinjection, the water isolation of upper and lower strata, permeability and sealing of the reinjection layer. Based on Darcy's law of groundwater and Dupuit's theory, a mathematical model of steady flow of water injection well …
Quantitative Study Of 3d Numerical Simulation On Optimizing Borehole Layout Spacing Of Gas Drainage, Chen Yuexia, Chu Tingxiang, Chen Peng, Tang Yang
Quantitative Study Of 3d Numerical Simulation On Optimizing Borehole Layout Spacing Of Gas Drainage, Chen Yuexia, Chu Tingxiang, Chen Peng, Tang Yang
Coal Geology & Exploration
In order to optimize the spacing of boreholes and realize efficient drainage, based on the fluid solid coupling model, a three-dimensional geometric model was established to make it closer to the field reality, the gas drainage processes of a coal mine with different borehole spacing were simulated using COMSOL software. The results show that: the effective drainage area was visualized by the three-dimensional diagram of the isobaric surface with gas pressure of 0.74 MPa, and the influence of borehole spacing on the extraction efficiency was discussed. The results show that: the effective extraction radius is about 1.5 m during gas …