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Full-Text Articles in Engineering

Waveform Cross Correlation-Based Imaging Of Underground Seismic Data While Mining, Zhang Huanlan, Wang Baoli Aug 2020

Waveform Cross Correlation-Based Imaging Of Underground Seismic Data While Mining, Zhang Huanlan, Wang Baoli

Coal Geology & Exploration

Seismics while mining is a passive seismic detection technique using a shearer as seismic source. Because the shearer moves unceasingly and excites the continuous signals, the conventional data processing method cannot be applied directly. In the paper a cross-correlation method of segmented waveform was put forward, the effective signal travel time was extracted through the segmentation of the data generated the shear, and then the velocity imaging method was used to image the interior of the working face and the front of the cutting hole. The wave equation was used to carry out the seismics while mining numerical simulation of …


Model And Selection Criterion Of Zonal Preact Grouting To Prevent Mine Water Disasters Of Coal Floor Limestone Aquifer In North China Type Coalfield, Dong Shuning, Guo Xiaoming, Liu Qisheng, Wang Hao, Nan Shenghui, Zheng Shitian, Wang Yuhang Aug 2020

Model And Selection Criterion Of Zonal Preact Grouting To Prevent Mine Water Disasters Of Coal Floor Limestone Aquifer In North China Type Coalfield, Dong Shuning, Guo Xiaoming, Liu Qisheng, Wang Hao, Nan Shenghui, Zheng Shitian, Wang Yuhang

Coal Geology & Exploration

In order to promote the development of zonal preact grouting technology and establish a system of the technology to prevent mine water disasters of coal floor aquifer, the authors analyze and summarize the coal seam occurrence and hydrogeological conditions of the Carboniferous-Permian coalfields in China, starting from the engineering systematicity, focusing on the three main factors of drilling conditions, grouting layer selection and drilling technology in the engineering of zonal preact grouting to prevent mine water disasters of coal floor aquifer. The model of zonal preact grouting to prevent mine water disasters of coal floor aquifer is established, which can …


Integrated Monitoring Technology Of Water Inrush From Coal Seam Floor And Its Application, Duan Jianhua Aug 2020

Integrated Monitoring Technology Of Water Inrush From Coal Seam Floor And Its Application, Duan Jianhua

Coal Geology & Exploration

Karst water damage in floor is a common problem in North China type coalfield. Because of its characteristics of concealment and emergency, the prevention and control of water is faced with huge problems and challenges, monitoring and early warning technology of floor water inrush has become a necessary measure in the process of the safe production in coal mines. The formation and occurrence of floor water disaster have a process of evolution from conception, development to occurrence. In this process, the corresponding water inrush symptoms will be released in different stages of the floor crack and apparent resistivity of the …


Application Of Borehole Transient Electromagnetic Detection In The Test Of Hydraulic Fracturing Effect, Zhao Rui, Fan Tao, Li Yuteng, Wang Jikuang, Ma Yuan, Wang Bingchun, Liu Lei, Fang Zhe Aug 2020

Application Of Borehole Transient Electromagnetic Detection In The Test Of Hydraulic Fracturing Effect, Zhao Rui, Fan Tao, Li Yuteng, Wang Jikuang, Ma Yuan, Wang Bingchun, Liu Lei, Fang Zhe

Coal Geology & Exploration

Hydraulic fracturing technology is widely used in various aspects such as mine rock burst prevention and surrounding rock depressurization, but there has been a lack of efficient and intuitive technology for evaluating the fracturing effectiveness. To solve this problem, a three-component borehole TEM detection method using dynamic source and reception unit was proposed, and detection equipment and supporting construction techniques suitable for construction in hydraulic fracturing holes were developed. Two engineering tests have been carried out in a coal mine. By comparing the processing results of the vertical components of the two detection data before and after fracturing, a pure …


Construction Technology Of Vertical Concealed Laying Of Anti-Seepage Membrane For Water Cutoff Curtain In The Open-Pit Coal Mine, Li Wensong, Dang Yakun, Zhu Mingcheng, Gao Ya Aug 2020

Construction Technology Of Vertical Concealed Laying Of Anti-Seepage Membrane For Water Cutoff Curtain In The Open-Pit Coal Mine, Li Wensong, Dang Yakun, Zhu Mingcheng, Gao Ya

Coal Geology & Exploration

Anti-seepage membrane(HDPE geomembrane) is widely used in anti-seepage projects currently that mainly prevent pollution, leakage and diffusion, and its laying form was various. In an underground water cutoff curtain project of an open-pit coal mine in China, the anti-seepage membrane was laid vertically as the main body of the water cutoff curtain wall, and the largest concealed depth was about 50 m. The different groove sections was overlapping connected by using connection box technology. Through the grouting and backfilling process, the impermeability of the curtain wall was improved and the anti-seepage membrane was compacted. Finally, pumping test in the surrounding …


Water Absorption Characteristics And Their Influence On The Mechanical Properties Of Longmaxi Formation Shale In Northeastern Chongqing, Liu Hong, Xu Fenglin, Chen Qiao, Zhu Honglin, Su Degui, Feng Kelai Aug 2020

Water Absorption Characteristics And Their Influence On The Mechanical Properties Of Longmaxi Formation Shale In Northeastern Chongqing, Liu Hong, Xu Fenglin, Chen Qiao, Zhu Honglin, Su Degui, Feng Kelai

Coal Geology & Exploration

A certain amount of casing deformation occurs during the shale reservoir fracturing. There is a certain amount of clay minerals in shale, and after contacting with water-based fracturing fluid, it will show the same expansion characteristics and strength weakening effect as mudstone, which will increase the casing external load. Aiming at the Longmaxi Formation shale in the northeast of Chongqing, the self-absorption and swelling characteristics of shale under different solution systems are studied by physical experiments to analyze the effect of shale hydration on its rock mechanical properties. The results show that the water absorption of shale has a logarithmic …


Reasons Of Low Yield And Stimulation Measures For Cbm Wells In Junlian Area, Li Ying, Zheng Rui, Luo Kai, Zhu Yanming, Zhang Yimin Aug 2020

Reasons Of Low Yield And Stimulation Measures For Cbm Wells In Junlian Area, Li Ying, Zheng Rui, Luo Kai, Zhu Yanming, Zhang Yimin

Coal Geology & Exploration

Coalbed methane fields in Junlian area have good development potential, but the existence of a large number of low-production and low-efficiency wells has restricted the increase of productivity. This paper analyzes the coupling relationship between high-productivity wells and geological factors from the perspective of geological engineering integration, analyzes the causes of inefficient wells from three aspects of geology, drainage and engineering, and evaluates the corresponding reform measures. The results show that the formation of inefficient wells in the north and the west of the study area is mainly affected by gas-bearing properties, fault distribution, production horizons, production and drainage rhythms, …


Development Characteristics Of Freezing Temperature Field Of Coastal Soft Soil Strata, Chen Junhao, Zhuang Yan, Chen Bijian, Zhao Zhenwei, Wang Qiyun Aug 2020

Development Characteristics Of Freezing Temperature Field Of Coastal Soft Soil Strata, Chen Junhao, Zhuang Yan, Chen Bijian, Zhao Zhenwei, Wang Qiyun

Coal Geology & Exploration

In order to research the temperature fields and development law of freezing in the construction of connected aisle in coastal soft soil stratum, based on connected aisle between Luoxiu road station and Baise road station of Shanghai subway Line 15, the thickness and average temperature of frozen curtain, and the freezing process were analyzed. The temperature fields and development law of freezing were predicted by the three-dimensional numerical model of the connected aisle and the temperature data which were analyzed. The results show that the inherent pressure in soft soil causes initial pressure in the pressure relief hole. A lot …


Collapse Column Identification Method Based On Seismic Waveform Indication Inversion And Its Application, Wan Zhaofei, Guo Zenghu, Wang Peng, Tang Meizhen, Han Tianbao, Liu Liangqiong Aug 2020

Collapse Column Identification Method Based On Seismic Waveform Indication Inversion And Its Application, Wan Zhaofei, Guo Zenghu, Wang Peng, Tang Meizhen, Han Tianbao, Liu Liangqiong

Coal Geology & Exploration

During the CBM exploration and development, the collapse column is one of the important factors restricting the exploration effectiveness of coalbed methane. Therefore, the effective identification of collapse column is of great significance for the improvement of CBM exploration. The previous identification methods are based on the discontinuity of the in-phase axis of seismic reflection caused by collapse column. In this paper, the collapse column is innovatively regarded as a kind of geological anomaly, and the identification and prediction of the collapse column are attempted by means of waveform indication inversion. Firstly, through the analysis of logging data and geological …


Experimental Study On The Frequency Dispersion Response Of Composite Electrical Properties Of Coal, Meng Hui, Li Jian, Lei Dongji, Wang Yajuan Aug 2020

Experimental Study On The Frequency Dispersion Response Of Composite Electrical Properties Of Coal, Meng Hui, Li Jian, Lei Dongji, Wang Yajuan

Coal Geology & Exploration

In order to study the characteristics of frequency dispersion response of the composite electrical properties of coal, the real part R and imaginary part X of the composite resistance of coal body at different direction in different measured areas were measured, the frequency dispersion characteristics were analyzed, different classical models were used to conduct data inversion and comparison. The results show that the composite electrical property parameters(absolute value of R and X) of coal are inversely proportional to the measured area, the characteristic frequency points are not offset, the X-frequency divergence decreases with the increase of measurement area; …


Research Status And Prospect Of Drill Pipe Thread Used In Coal Mine, Tian Dongzhuang, Chen Yanyu, Li Qing, Dong Mengmeng, Mou Peiying Aug 2020

Research Status And Prospect Of Drill Pipe Thread Used In Coal Mine, Tian Dongzhuang, Chen Yanyu, Li Qing, Dong Mengmeng, Mou Peiying

Coal Geology & Exploration

Drill pipe is one of the main device for drilling construction of gas drainage, water detection and drainage and geological exploration. Due to complicated force conditions and using environment of drill pipe, accidents in boreholes caused by the failure of drill pipe threads are common. According to different structural classification, the characteristics of drill pipe thread structure in coal mines are introduced in detail; the current research status of thread stress distribution and failure analysis of thread are summarized. The research methods of thread stress distribution mainly include analytical method, finite element method and test method. The main causes of …


Effect Of Calcination Time On The Physicochemical Properties And Photocatalytic Performance Of Carbon And Nitrogen Co-Doped Tio2 Nanoparticles, Emile Salomon Massima Mouele, Mihaela Dinu, Franscious Cummings, Ojo O. Fatoba, Myo Tay Zar Myint, Htet Htet Kyaw, Anca C. Parau, Alina Vladescu, M. Grazia Francesconi, Sara Pescetelli, Aldo Di Carlo, Antonio Agresti, Mohammed Al-Abri, Sergey Dobretsov, Mariana Braic, Leslie F. Petrik Aug 2020

Effect Of Calcination Time On The Physicochemical Properties And Photocatalytic Performance Of Carbon And Nitrogen Co-Doped Tio2 Nanoparticles, Emile Salomon Massima Mouele, Mihaela Dinu, Franscious Cummings, Ojo O. Fatoba, Myo Tay Zar Myint, Htet Htet Kyaw, Anca C. Parau, Alina Vladescu, M. Grazia Francesconi, Sara Pescetelli, Aldo Di Carlo, Antonio Agresti, Mohammed Al-Abri, Sergey Dobretsov, Mariana Braic, Leslie F. Petrik

Mining Engineering Faculty Research & Creative Works

The application of highly active nano catalysts in advanced oxidation processes (AOPs) improves the production of non-selective hydroxyl radicals and co-oxidants for complete remediation of polluted water. This study focused on the synthesis and characterization of a highly active visible light C–N-co-doped TiO2 nano catalyst that we prepared via the sol-gel method and pyrolyzed at 350 °C for 105 min in an inert atmosphere to prevent combustion of carbon moieties. Then we prolonged the pyrolysis holding time to 120 and 135 min and studied the effect of these changes on the crystal structure, particle size and morphology, electronic properties and …


A Mechanism Of Electric Charge Losses In Adiabatically Compressed Ferroelectrics, Sergey I. Shkuratov, Jason Baird, Vladimir G. Antipov, Jay B. Chase Jul 2020

A Mechanism Of Electric Charge Losses In Adiabatically Compressed Ferroelectrics, Sergey I. Shkuratov, Jason Baird, Vladimir G. Antipov, Jay B. Chase

Mining Engineering Faculty Research & Creative Works

A ferroelectric depolarized by high strain-rates induced by the passage of adiabatic shock waves releases a high-density electric charge, initiating the generation of high voltage and megawatt power levels. Additionally, this depolarization process alters physical and mechanical properties that might cause energy and electric charge losses in the ferroelectric materials. We report, herein, the results of an experimental study of electric charge losses in Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 and Pb0.99(Zr0.52Ti0.48)0.99Nb0.01O3 ferroelectrics subjected to shock compression. We found that electric charge losses mainly occur in the compressed zone of ferroelectric elements, i.e., shock compression is an essential part of the charge loss mechanism. Based …


Mining The Borderlands: Industry, Capital, And The Emergence Of Engineers In The Southwest Territories, 1855-1910. Grossman, Sarah E.M. University Of Nevada Press, 2018, James Altman Jun 2020

Mining The Borderlands: Industry, Capital, And The Emergence Of Engineers In The Southwest Territories, 1855-1910. Grossman, Sarah E.M. University Of Nevada Press, 2018, James Altman

Executive Vice President & Provost Faculty Research

In Mining the Borderlands: Industry, Capital, and the Emergence of Engineers in the Southwest Territories, 1855‐1910, distinguished scholar Sarah E.M. Grossman examines the early history of commercial mining along the US‐Mexico border. She brings to the task her extensive knowledge of the region, and a forensic detective's thirst for the truth. Her mission is to understand precisely how much, and in what specific ways, various commercial mining ventures in the desert Southwest contributed not only to the economic development of the region, but also to improvements in mining techniques, engineering methods, equipment, efficiency, working conditions, mining education, and most importantly, …


Water Environment Comprehensive Forewarning For Waterlogged Area In Huainan Based On Weber-Fechner Law, Pei Wenming, Zhang Hui, Ju Changhua, Yao Suping, Ren Yongle, Ma Mengxiao, Qiu Kuanbiao Jun 2020

Water Environment Comprehensive Forewarning For Waterlogged Area In Huainan Based On Weber-Fechner Law, Pei Wenming, Zhang Hui, Ju Changhua, Yao Suping, Ren Yongle, Ma Mengxiao, Qiu Kuanbiao

Coal Geology & Exploration

In area with high groundwater level in the east of China, long-time underground coal mining results in a large subsidence water area on the surface. The risk of water environment pollution in subsidence waters is increasing gradually with the influence of human activities. According to Weber-Fisher law, this paper took Panji waterlogged area of Huainan as the research object, selected the water quality evaluation indexes closely related to the water environment of the waterlogged area, analyzed the water environmental conditions of the waterlogged area in different periods, and quantitatively reflected the time and the area of the water environment quality …


Performance Test And Proportioning Optimization Of Loess-Based Grouting Materials In Coal Mining Subsidence Area Of Northern Shaanxi, Cao Xiaoyi, Wang Yutao, Liu Xiaoping, Cao Zubao, Wu Boqiang Jun 2020

Performance Test And Proportioning Optimization Of Loess-Based Grouting Materials In Coal Mining Subsidence Area Of Northern Shaanxi, Cao Xiaoyi, Wang Yutao, Liu Xiaoping, Cao Zubao, Wu Boqiang

Coal Geology & Exploration

Grouting is the main treatment method of mining subsidence area, and the grouting materials have great influence on the grouting effect and cost. Taking the grout mix composed of loess and cement used in northern Shaanxi as the research object, the viscosity, the gelation time, the stone rate and 28 d uniaxial unconfined compressive strength of loess grout were studied by single factor and orthogonal tests. The influencing factors and changing rule of each index were analyzed. Meanwhile, the GA-BPNN prediction model of loess-based grout was established, and the multi-objective global optimization was carried out through GA. The grout ratio …


Stacking Angle Of Slurry-Aeolian Sand Dual-Phase Medium Filling Material, Bai Zhongrong Jun 2020

Stacking Angle Of Slurry-Aeolian Sand Dual-Phase Medium Filling Material, Bai Zhongrong

Coal Geology & Exploration

Stacking angle is an important parameter to describe the spatial accumulation pattern of filling material in the goaf. It has important guiding significance for determining the drilling distance, optimizing the slurry configuration and adjusting the grouting process parameters. In order to grasp the variation law of stacking angle of slurry-aeolian sand dual-phase medium filling material, using self-flow stacking model experiment of tailings and rheological properties experiment, the mixing ratio of aeolian sand was taken as a variable to determine the slurry accumulation parameters and rheological parameters on different conditions of sand ratio. Based on this, Sofra & Boger formula was …


Regional Distribution And Geotectonic Control Of Late Permian Tectonically Deformed Coal In Zhina Coalfield, Zhou Peiming, Gao Wei, Deng Lan, Fu Wei Jun 2020

Regional Distribution And Geotectonic Control Of Late Permian Tectonically Deformed Coal In Zhina Coalfield, Zhou Peiming, Gao Wei, Deng Lan, Fu Wei

Coal Geology & Exploration

In order to find out the tectonically deformed coal distribution law of Zhina coalfield, by sorting out and analyzing the data of more than 200 coal-bearing structural units including Bide syncline, Santang syncline, Zhuzang syncline, Arcong syncline and Guanzhai syncline in Zhina coalfield, Guizhou Province, combined with logging curve analysis, the regional distribution characteristics of coal body structure and structural control factors of No.6, No.16 and No.27 main coal seams are comprehensively analyzed. The study shows that from the west to the east, the proportion of tectonically deformed coal in Zhina coalfield increases gradually. The coal in the western part …


Physical Simutation Experiment Investigation On Hydraulic Fracture Propagation In High-Dip Coal Seam, Jiang Wei, Zhang Jun, Zhong Jie, Zhao Chen, Tang Zhuyun, Lu Haibing, Yi Xinbin, Wang Hai Jun 2020

Physical Simutation Experiment Investigation On Hydraulic Fracture Propagation In High-Dip Coal Seam, Jiang Wei, Zhang Jun, Zhong Jie, Zhao Chen, Tang Zhuyun, Lu Haibing, Yi Xinbin, Wang Hai

Coal Geology & Exploration

In order to study the hydraulic fracture geometry in high-dip coal seam, a large-scale true triaxial fracturing simulation system was used to carry out physical simulation experiments, and the hydraulic fracture geometry of the maximum horizontal principal stress along the strike direction and along the dip direction-in 60° dip coal seam were investigated respectively. Experimental results of the maximum principal stress direction along the strike direction show that: hydraulic fracture initiation is easily; fracture height is limited in the whole time; fracture connectivity is good; fracture propagates mainly along bedding and natural fracture, vertical fracture is formed; the influence of …


Surface Efficient Gas Extraction Mode Based On Full Coverage Of Working Face, Fang Jiawei, Han Baoshan, Zhou Jiajia, Wang Zhengxi, Zhang Dingliang, Liu Jia, Xu Jianjun Jun 2020

Surface Efficient Gas Extraction Mode Based On Full Coverage Of Working Face, Fang Jiawei, Han Baoshan, Zhou Jiajia, Wang Zhengxi, Zhang Dingliang, Liu Jia, Xu Jianjun

Coal Geology & Exploration

Aiming at the problems of soft and broken coal seam, low permeability, difficulty in gas extraction and low drainage efficiency in working face, a full-coverage mode for gas extraction in working face through the horizontal well group with staged fracturing roof at both ends is proposed. Taking a mine in Suxian mining area of Huaibei coalfield as an example, based on the characteristics of in-situ stress and working face distribution, combined with the analysis of gas geological conditions and coal seam mechanical properties in the area, the cross section dipole sonic logging method was used to optimize the orientation of …


Practice And Understanding Of Multi-Layer Drainage Of Cbm Wells In Liupanshui Area, Liu Jiang, Sang Shuxun, Zhou Xiaozhi, Bi Caiqin, Jin Jun, Shan Yansheng Jun 2020

Practice And Understanding Of Multi-Layer Drainage Of Cbm Wells In Liupanshui Area, Liu Jiang, Sang Shuxun, Zhou Xiaozhi, Bi Caiqin, Jin Jun, Shan Yansheng

Coal Geology & Exploration

To improve the effect of drainage and extraction of coalbed methane wells, it is necessary to divide the drainage and production stages reasonably and formulate corresponding control measures. Based on the previous exploration and trial production of coalbed methane in Liupanshui area, this paper analyzed the geological characteristics of coalbed methane and the development characteristics of coal reservoirs in the area, and studied the drainage effect of the combined layers of two wells comparatively. The research shows that the area has several basic characteristics, including many coal seams, thin single-layer thickness, high gas content, high reservoir pressure, low coal seam …


Application Of Time Series Model In Water Inflow Prediction Of Working Face, Shi Longqin, Wang Yaru, Qiu Mei, Gao Weifu Jun 2020

Application Of Time Series Model In Water Inflow Prediction Of Working Face, Shi Longqin, Wang Yaru, Qiu Mei, Gao Weifu

Coal Geology & Exploration

In practical production of mines, the prediction of mine water inflow is of great significance for mine water prevention and control. Taking working face 1301 of Yuncheng coal mine as the research object, and without considering the influence of seasonal factors, ARIMA-the time series analysis model-is used to establish the functional relationship between mine water inflow and time, which proves that the time series of water inflow in working face 1301 of Yuncheng coal mine is affected by seasonal factors. Then, based on the principle of addition and decomposition of time series, the long-term trend, seasonal indexes, circulating factors and …


Fractal Theory-Based Seepage Model Of Hershel-Bulkley Fluid In Porous Medium, Yang Xian, Lu Wei, Jin Xin, Chen Juan, Feng Xingfa Jun 2020

Fractal Theory-Based Seepage Model Of Hershel-Bulkley Fluid In Porous Medium, Yang Xian, Lu Wei, Jin Xin, Chen Juan, Feng Xingfa

Coal Geology & Exploration

Slurry is a kind of widely-used engineering fluid. Slurry will seeps into the formation in the process of construction, which has a certain impact on the project. In order to make deeper study on the seepage mechanism of slurry, the formation is simulated as porous medium, the slurry is simulated as Hershel-Bulkley fluid which can more comprehensively reflect its rheological properties, and the seepage model of Hershel-Bulkley fluid in porous medium was established based on Fractal theory. Based on the calculation results of seepage model, the effect of pressure gradient, flow index, consistency coefficient and porosity on the instantaneous average …


Test Of Mechanical Properties Of Limestone Under Hydraulic Pressure-Stress Coupling, Tian Shukun Jun 2020

Test Of Mechanical Properties Of Limestone Under Hydraulic Pressure-Stress Coupling, Tian Shukun

Coal Geology & Exploration

To study the mechanical properties of limestone with water-rich saturated circumstance under water pressure-stress coupling, compression failure tests of limestone samples with different water pressure were carried out by using a self-developed permeability test device, the device can realize uniaxial compression test. Then, the stress-strain characteristics of limestone, the effect of hydraulic pressure on uniaxial compressive strength, the elastic modulus and the deformation modulus, and the correlation between breaking characteristics and hydraulic pressure were tested. The results show that the increased hydraulic pressure has a significant influence on the stress-strain curve and strength characteristics. With the increase of hydraulic strength, …


Development Characteristics Of Water Conducted Fracture Zone Based On Overburden Structural Effect, Cao Zubao, Wang Qingtao Jun 2020

Development Characteristics Of Water Conducted Fracture Zone Based On Overburden Structural Effect, Cao Zubao, Wang Qingtao

Coal Geology & Exploration

In order to study the roof water disaster caused by coal mining in Huanglong coalfield, taking mining failure of layered overburden as research object, four typical composite structural models for coal-soft rock-hard rock-soft rock-hard rock(combination I), coal-soft rock-soft rock-hard rock-hard rock(combination Ⅱ), coal-hard rock-soft rock-hard rock-soft rock(combination Ⅲ) and coal-hard rock-hard rock-soft rock-soft rock(combination IV) were generalized. Numerical simulation and theoretical calculation were used to analyze the mining failure characteristics of different overburden combinations and correlation between water conducting fissures and lithologic combination structure of overburden. The law of the effect of overburden structure on the development height of water …


The Law Of Soaking Infiltration And Collapse Deformation In Typical Loess-Paleosol Series, Zhao Jingang, Lyu Yuanqiang, Chao Jun, Yang Zhe, Xia Meng Jun 2020

The Law Of Soaking Infiltration And Collapse Deformation In Typical Loess-Paleosol Series, Zhao Jingang, Lyu Yuanqiang, Chao Jun, Yang Zhe, Xia Meng

Coal Geology & Exploration

In order to investigate the law of moisture migration and collapse deformation of the typical loess-paleosol series, on the basis of water immersion test of the large test pits of Xi’an North-airport intercity rail transit in the loess tableland of Weibei, the real-time in-site observation was adopted, the soaking infiltration and collapse deformation of collapsible soil layer under conditions of non water seepage hole were traced and tested. The results show that: The movement of water immersion is dominated by vertical movement in the early stage. The whole form is like a continuous increase of “weight” shape. As the water …


Numerical Calculation Of Temperature Field Of Freeze-Sealing Pipe Roof Method In Gongbei Tunnel, Long Wei, Rong Chuanxin, Duan Yin, Guo Ke Jun 2020

Numerical Calculation Of Temperature Field Of Freeze-Sealing Pipe Roof Method In Gongbei Tunnel, Long Wei, Rong Chuanxin, Duan Yin, Guo Ke

Coal Geology & Exploration

This paper took the Gongbei tunnel in the Zhuhai Connection Section of the Hong Kong-Zhuhai-Macao Bridge as an example to study the development of the temperature field of the Freeze-Sealing Pipe Roof Method. Based on the heat transfer theory of two-dimensional porous media, the FEM software COMSOL was used to numerically analyze the actual working conditions of the active freezing period, the numerical calculation was verified by field measurement. The development and distribution of the temperature field before and after the opening of the special-shaped freezing pipes was studied. The results showed that: when freezing for 30 days, the concrete …


Influence Factors And Formation Properties Of Temperature Field In The Frozen Wall Of Double Ring Pipes, Li Huaixin, Lin Bin, Wang Peng Jun 2020

Influence Factors And Formation Properties Of Temperature Field In The Frozen Wall Of Double Ring Pipes, Li Huaixin, Lin Bin, Wang Peng

Coal Geology & Exploration

In order to research the change law of the temperature field of the frozen wall of double-circle pipes, an auxiliary shaft in Huainan coalmine was taken as the research object, the FLAC3D software was used to numerically simulate the formation process of the temperature field of the frozen wall of double-circle pipes and the influence of different factors on average temperature of frozen wall based on the relevant geological parameters. The research results show that temperature of the soil in the double-circle pipes is the lowest, and temperature on both sides increases gradually, the interval between frozen holes is …


Detection Technique And Application Of Transmission In-Seam Wave In Thin Coal Seam, Yang Hui Jun 2020

Detection Technique And Application Of Transmission In-Seam Wave In Thin Coal Seam, Yang Hui

Coal Geology & Exploration

Aiming at the problem of serious attenuation of channel wave in thin seam and its limited distance of propagation, a method of restricted CT imaging was proposed by using the furthest in-seam wave propagation distance. Firstly, the variation of in-seam wave frequency with different thickness of coal seam was studied by theoretical derivation. Taking a 1.5m thin seam as the main research object, the attenuation characteristics of channel wave were simulated by forward modeling, and the effective propagation distance of channel wave was determined. The actual data of No. 15 coal seam in a coal mine in Shandong Province shows …


Influence Of Parting In Composite Coal Seam On Interpretation Of Fault Throw By Channel Wave Seismic Exploration, Su Xiaoyun Jun 2020

Influence Of Parting In Composite Coal Seam On Interpretation Of Fault Throw By Channel Wave Seismic Exploration, Su Xiaoyun

Coal Geology & Exploration

The channel wave seismic exploration technology has achieved relatively reliable result in detection of faults, collapse columns and the change of coal thickness in working faces, now becomes the preferred method for detection of underground geological structures. But for detection of geological structures in partings of composite coal seams the method has still certain problems. In order to study the influence of partings in composite coal seams on detection of channel wave seismic exploration, various models were built by changing thickness, lithology of parting in composite coal seams and experimenting with channel wave seismic detection in Shanxi to study how …