论文翻译排版范文

专业外语文献翻译 结课论文 专业外语文献翻译 结课论文 学学 院 院 班班 级 级 姓姓 名 名 学学 号 号 2 安全工程专业外语文献翻译评分标注 评价项目评分标准得分 排版 30 分 格式完全符合模板要求满分 每一大项不符合之处 酌情扣分 翻译是否有错别字 10 专业术语 数字 统计学方法等翻译是否准确 30 翻译质量 70 分 语句通顺 连贯 符合中文表达习惯 30 总分 百分制 总评 五级制 评阅人 日期 3 Experimental Study on the Bedding Effect about Gas Seepage Characteristics of Fracture Coal Body Coal under the Stress Loading and Unloading Process TIAN Kun yun Department of Safty Science Engineering Henan University of Engineering Zhengzhou 451191 China Abstract In order to obtain the gas permeability characteristics of different bedding direction fractured coal under the action of stress loading and unloading the experiment research was carried out employing three stress axis gas penetration simulation experiment device The results showed that in the stress loading process the trend about this two kinds of bedding fissures coal body was similar which the permeability decreased with the increase of effective stress The permeability of the two coal samples decreased by 99 01 and 80 49 when the effective stress was loaded to the maximum value In the stress unloading process permeability of the two coal samples increased with the decrease of effective stress The permeability of the two coal samples recovered to 87 45 and 68 8 5 of the minimum value when the effective stress unloaded from 11 65 to 8 98 MPa Permeability increase amplitude was 736 78 and 99 67 when the effective stress was 4 98MPa The increase amplitude of DN1 coal sample was much bigger under the same unloading condition The research results can provide certain reference for the gas drainage borehole layout maximizing the the gas extraction effect Key words Loading and unloading Fracture coal body Seepage characteristics Raw coal samples The bedding is widely distributed in the coal seam and determines the stability of coal seam especially the gas flow state 1 Integrity of coal body is destroyed by the bedding fissures meanwhile the stress distribution state of coal seam changes to a great extent 2 bedding fissures is one of the main control factors that determine the strength of coal body deformation and gas permeability characteristics Bedding fissure will develop penetrate even deformate and destruct after the mining induced influence this has a great influence on the gas seepage and diffusion directly determining the characteristics of gas migration and accumulation and then greatly affecting the gas drainage effect of coal seam As is known gas drainage is the most basic technical measures to control coal mine gas 3 coal seam permeability is the most important index to determine the gas drainage effect 4 5 coal structure is an important index to determine the coal seam permeability Consequently gas drainage borehole design according to the characteristics of different bedding fissure is essential for improving the gas drainage effect and achieving gas drainage maximum Research about the influence coal bedding fissure to the permeability has been carried out at home and abroad Experimental study on effect of coal body structure to gas permeability characteristics has been carried out by HUANG Xueman 6 research results showed that the effect of coal structure anisotropy on permeability was great difference in permeability was almost one order of magnitude Research on permeability characteristics of layered natural coal under different loading and unloading has conducted by Pan Rongkun et al 7 and the theoretical model between fractured coal bedding and the effective stress was established Using the fluid solid coupling three axis servo seepage device with gas coal seepage test about two kinds of raw coal samples parallel and vertical to coal bedding direction under different stress conditions was carried out by DENG Bozhi et al 8 results showed that the permeability difference about the two coal samples was mainly caused by the difference of the fracture degree of the Z axial direction of the coal samples Koenig and Stubbs 9 in the United States have carried out research work on the permeability of coal seams in the Warrior basin results showed that the permeability varied several tens of times in different bedding direction A large number of experimental studies on the permeability of coal samples under different bedding conditions have carried out by Jishan Liu 10 11 Huoyin Li 12 et al conclusions showed that coal body bedding had big impact on permeability characteristics All the research results analyzed the influence about coal body bedding to gas permeability these have a certain guiding significance to reasonable gas drainage borehole arrangement In the actual mining process of coal mine coal body is in the change stress field 13 Therefore It is necessary to carry out research on gas seepage rule and its failure deformation characteristics about fracture coal body in different bedding direction under loading and unloading conditions For this purpose large lump coal sample with bedding structure was collected two different kinds of raw coal samples with parallel and vertical bedding were prepared the related research 4 work was carried out in the laboratory 1 Experimental method 1 1 Simulation experiment system The independent research and development three axis stress gas permeability simulation experiment device was employed in the experiments Experimental apparatus is shown in figure 1 The main parameters from each attachment of the experimental system are as follows 14 Range of axial compression 0 100MPa precision 0 1Mpa Range of confining pressure range 0 60MPa precision 0 1MPa Range of gas pressure range 0 10MPa precision 0 1MPa Range of mass flowmeter 0 30SCCM precision 1 5 F S Specifications of three axis stress clamping device 50 100 5 1 2 3 4 5 5 6 7 8 9 10 11 13 14 12 10 5 15 16 17 17 18 19 20 21 1 Water tank 2 Water flow meter 3 Metering pump 4 Water pressure gauge 5 The valve 6 O ring seal 7 Pressure chamber 8 Confining pressure booster aprons 9 Coal test specimen 10 Oil pressure gauge 11 Confining pressure control valve 12 Axial pressure control valve 13 Fuel tank 14 Computer 15 Pressure release valve 16 High pressure gas 17 Gas Pressure gauge 18 Gas water separator 19 The gas flow meter 20 Damper 21 Vacuum pump Fig 1 The three axis stress gas permeability simulation experiment device 1 2 Preparation for experimental coal sample The coal samples used in the experiment comes from 11031 working face in Daning coal mine The No 3 coal seam in this place have no obvious geological structural damage in the process of coal forming This coal seam is primary structure and low metamorphic bituminous coal Coal seam is mainly with horizontal bedding in addition the bedding is clearly visible The raw samples for experiment were gain through the following three steps namely collection of the large lump coal coal sample machining in the laboratory and grinding finished product 1 Collection the large lump coal underground which the shape is rule relatively and the bedding is clear 2 Coring with rock core taking machine along the vertical and parallel to bedding direction 3 Grinding the two ends and the sides of the standard cylindrical samples ensuring the uneven degree less than 0 02mm 15 Finally the standard coal sample was preparaed successfully the size is 50mm 100mm Two kinds of different bedding direction coal samples were choosen which the bedding was clear and polished carefully the two coal sample numbers were DN1 and DN2 as shown in Figure 2 The basic physical parameters and industrial analysis of the raw coal samples are shown in Table 1 5 a Parallel bedding b Vertical bedding Fig 2 Samples with different bedding fracture direction a Parallel bedding b Vertical bedding Fig 3 Sketch about samples with different bedding fracture direction Tab 1 Basic parameters of coal samples Mad Aad Vdaf The initial velocity of gas emission P Type failure of coal Protodyakonov coefficient f True density g cm 3 Apparent density g cm 3 Porosity 3 2820 2513 736 5 1 351 61 474 82 1 3 Experimental programme Large amount of gas is contained in the coal Initially the coal body is in the state of static stress original stress zone With the mining advance the coal body needs to experience the process of loading stress concentration and unloading pressure relief belt 16 Corresponding to this the stress loading and unloading path is as follows Under the condition of certain gas pressure according to the actual situation of the Daning coal mine here the gas pressure is 0 8Mpa the axial compression and confining pressure of the coal samples were loaded to 12MPa after that confining pressure were unload at a uniform speed under constant axial pressure the value is 12MPa the speed of confining pressure and axial compression Loading and unloading is 0 01MP s Under the the same stress loading unloading path the permeability about parallel and vertical bedding fracture coal samples will be discussed Gas flow through the coal samples is collected automatically by the flow meter which is built in experimental system permeability is caculated via calculating program calculation of permeability is based on the following formula 17 18 00 22 12 2 Q PL K PPA In the formula K is the coal sample permeability mD Q0 is the seepage quantity cm3 s P0 is atmospheric pressure of the measuring point MPa is gas dynamic viscosity coefficient here takes 10 8 10 6Pa s P1 is the inlet gas pressure here takes 0 8MPa P2 is the outlet gas pressure here takes 0 1MPa A is the sectional area of coal samples cm L is the length of coal samples cm Effective stress of the coal sample is calculated according to the following formula 21 2 1 2 3 1 PP wze In the formula e is the effective stress z is the axial pressure of the coal samples w is the confining pressure of the coal samples P1 is the inlet gas pressure here takes 0 8MPa P2 is the outlet gas pressure here takes 0 1MPa The specific experimental programs is shown in table 2 Tab 2 The experimental scheme about the raw coal samples Inlet gas pressure P1 MPa Outlet gas pressure P2 MPa Axial compression z MPa Confining pressure w MPa Effective stress e MPa 0 80 1221 65 0 80 1443 65 0 80 1665 65 0 80 1887 65 0 80 110109 65 Loading process 0 80 1121211 65 0 80 1121211 65 0 80 1121010 32 0 80 11288 98 0 80 11267 65 0 80 11246 32 Unloading process 0 80 11224 98 2 Experimental results and analysis 2 1 Experimental results Under the action of stress loading and unloading the permeability of the parallel and vertical bedding direction coal samples are shown in table 3 7 Tab 3 Permeability of coal samples during loading and unloading process Permeability k mD Effective stress e MPa Coal sample DN1 Coal sample DN2 1 650 1645560 025392 3 650 0783030 014896 5 650 0352500 010213 7 650 0224360 007768 9 650 0117830 006358 Loading process 11 650 0013010 004952 11 650 0013010 004952 10 320 0021860 0050412 8 980 0024390 0052932 7 650 0038620 0061452 6 320 0044140 0072132 Unloading process 4 980 0108860 0098884 2 2 Analysis of experimental results Based on the permeability experimental results the permeability and effective stress evolution characteristic curves of DN1 and DN2 coal samples were drawn respectively during the loading and unloading process as shown in Figure 4 0 00 0 02 0 04 0 06 0 08 0 10 0 12 0 14 0 16 0 18 0123456789101112 Effective stress e MPa Permeability k mD Loading process of coal samples DN1 Unloading process of coal samples DN1 a Parallel bedding 0 000 0 005 0 010 0 015 0 020 0 025 0 030 0123456789101112 Effective stress e MPa Permeability k mD Loading process of coal sample DN2 Unloading process of coal sample DN2 b Vertical bedding Fig 4 Permeability evolution characteristics of coal samples during loading and unloading process Seen from table 3 and figure 4 1 In the stress loading process the trend about this two kinds of bedding fissures coal body was similar which the permeability decreased with the increase of effective stress The permeability of the two coal samples 8 decreased by 78 5 and 59 78 when the effective stress was loaded to 5 65MPa This showed that the two coal samples had high response to the loading stress in initial stage of the stress loading The main reason is that cracks are prone to closed because of compression therefore permeability decline range was very rapid in the initial stage of stress loading tended to be gentle in later stage The initial gas permeability value of DN1 and DN2 coal samples was 0 164556mD and 0 025392mD respectively the ratio of the two permeability value namely k0DN1 k0DN2 was 6 48 1 When the effective stress load to the maximum value 11 65MPa the permeability of the two coal samples reduced to 0 010886mD and 0 009888mD respectively falling by 99 01 and 80 49 The permeability decreasing amplitude of DN1 coal sample was bigger this fully illustrated that the parallel bedding coal sample is easier to be compacted in the tress loading process 2 In the stress unloading process permeability of the two coal samples increased with the decrease of effective stress The permeability of the two coal samples recovered to 87 45 and 68 8 5 of the minimum value when the effective stress unloaded from 11 65 to 8 98MPa Permeability increase amplitude was 736 78 and 99 67 when the effective stress was 4 98MPa The increase amplitude of DN1 coal sample was much bigger under the same unloading condition 3 The permeability of the two coal samples decreased with the increase of the effective stress effective stress is the key factor that determines the permeability value directly Permeability change trend of the two coal samples was similar the decline range was very rapid in the initial stage of stress loading tending to be gentle in later stage Can been seen according to experimental results contrast as shown in figure 5a the permeability of DN1 coal sample was always bigger than DN2 Gas permeation degree is closely related to the bedding development direction the fracture network of parallel bedding direction is relatively developed under the same stress condition gas permeates more easily along bedding direction the permeability value is bigger 19 On the contrary for the vertical bedding coal sample gas penetration capacity through the bedding is impeded by the coal matrix its permeability is relatively small 20 Therefore gas drainage borehole should be arranged in the direction along the bedding in the not relief coal seam in order to maximize the gas drainage effect 4 Penetration capacity of DN1 coal sample had almost lost when the stress loaded to the maximum Can be seen from figure 5 b the permeability of DN1 coal sample was always smaller than DN2 during the whole stress unloading process The reason is that the crack permanent damage degree of coal sample DN1 is bigger than DN2 in the stress unloading process and is hard to recover Therefore gas drainage borehole should be arranged in the direction vertical the bedding in the relief coal seam 0 00 0 02 0 04 0 06 0 08 0 10 0 12 0 14 0 16 123456789101112 Effective stress e MPa Permeability k mD Permeability curve of coal sample DN1 during loading process Permeability curve of coal sample DN2 during loading process a Loading process 9 0 000 0 002 0 004 0 006 0 008 0 010 0 012 456789101112 Effective stress e MPa Permeability k mD Permeability curve of coal sample DN1 during unloading process Permeability curve of coal sample DN2 during unloading process b Unloading process Fig 5 Permeability contrast diagram of different bedding direction coal samples during loading and unloading process 3 Conclusion Experimental study on the gas permeability about parallel and vertical bedding fissures coal body was carried out under the same loading or unloading path and gas pressure permeability evolution law about the two kinds of bedding fissures coal body was revealed the main conclusions are as follows 1 In the stress loading process the trend about this two kinds of bedding fissures coal body was similar which the permeability decreased with the increase of effective stress Permeability decline range was very rapid in the initial stage of stress loading tending to be gentle in later stage The permeability of the two coal samples decreased by 99 01 and 80 49 the DN1 coal sample almost lost the permeability ability 2 In the stress unloading process permeability of the two coal samples increased with the decrease of effective stress permeability increase amplitude was 736 78 and 99 67 when the effective stress was 4 98MPa The increase amplitude of DN1 coal sample was much bigger 3 The permeability of DN1 coal sample was always greater than DN2 coal sample in the stress loading process therefore gas drainage borehole should be arranged in the direction along the bedding in the not relief coal seam in order to maximize the gas drainage effect In contrast the permeability of DN2 coal sample was always greater than DN1 coal sample in the stress unloading process this showed that the extent of internal cracks permanent damage about DN1 coal sample was greater and the internal cracks was difficult to restore Therefore gas drainage borehole should be arranged in the direction vertical the bedding in the relief coal seam Acknowledgements Supported by Natural Science Foundation of China 51604091 51174082 References 1 LIN Baiquan ZHANG Jianguo Mine gas drainage theory and technology M Xuzhou China University of Mining Press 1996 2 CHENG Yuanping FU Jianhua YU Qixiang Development of gas ex traction technology in coal mines of China J Journal of Mining Safety Engineering 2009 26 2 127 139 3 Bennett J G Broken coal J International Journal of Fuel 1936 10 22 39 4 ZHU Jie JIANG Yaodong ZHAO Yixin et al Experimental study on permeability of coal samples under the simultaneous action of unloading and loading J Journal of China Coal Society 2010 35 S 76 79 5 PAN Rongkun WANG Li CHEN Xiangjun et al Study on permeability characteristics of unloading coal body and stress effect of micro structure J Coal Science and Techno