采矿工程专业毕业论文--外文翻译.doc

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1、英文原文： Analytical model and application of stressdistribution on mining coal floor Abstract：Given the analysis of underground pressure，a stress calculation model of cola floor stress has been established based on a theory of elasticityThe model presents the law of stress distribution on the relativel

2、y fixed position of the mining coal floor：the extent of stress variation in a fixed floor position decreases gradually along with depthThe decreasing rate of the vertical stress is clearly larger than that of the horizontal stress at a specific depthThe direction of the maximum principal stress chan

3、ges gradually from a vertical direction to a horizontal direction with the advance of the working faceThe deformation and permeability of the rock mass of the coal floor are obtained by contrasting the difference of the principal stress established from theoretical calculations with curves of stress

4、-strain and permeability-strain from testsWhich is an important mechanical basis for preventing water inrush from confined aquifersKey words：model；coal floor；stress distribution；analysis1 IntroductionWith the development of coal seam mining，The stress field of rock strata of coal seam floors will ch

5、ange and continue to be redistributed because of the effect of miningThe results willbring on floor deformation，displacement and possible destruction to attain a new balance1A study of the law of stress distribution of floors has important，practical implications in understanding deformation and dest

6、ructive characteristics and predicting water inrush from floors and for designing suitable locations for tunnels and selecting maintenance methods when depth increasedAt present，the study of the law of stress distribution of floors mostly proceeds from a number of calculations based on finite elemen

7、t analyses and similar material tests2-6In this paper， the study of stress distribution of floors in relatively fixed positions is discussed analytically with a theory of elasticity and we present an application combined with actual data of a particular site2 Fundamental principleThe formulas of str

8、ess distribution are derived from the superposition principle，given the theory of elasticity on distributed loads on a semi-infinite plane7-8The vertical distribution load of AB on a semi-infinite plane is assumed to be q(x)，as illustrated in Fig.1.We want to solve the state of stress at a specific

9、point inside a semi-infinite plane，such as point M Supposing the coordinate of point is (x，z)，the micro-1ength d from the origin of coordinate is on the AB segment，the micro-concentration force dp=qd is regarded as its force and the state of stress of the micro-concentration force at point is define

10、d as follows In order to calculate the stress at point M from all distributed loads，the stress which is caused by every micro-concentration force is superposedWe need to integrate Eq.(1) from = -a to = b and Eq.(1) then becomes：3 Stress calculation of coal seam floor3.1Foundation of the mechanical m

11、odelBased on the theory of underground pressure，the mechanical model of supporting pressure in front of the working face can be simplified，as shown in Fig.29-11Where the OA segment is the plastic area，with a length of x0；the AB segment is the elastic area，with a length of L0x0In order to calculate e

12、asily the supporting pressure of both areas pz(1) ，pz(2)，without losing its rational，we can assume the following two linear functions：Where is the supporting pressure of the plastic area(kPa)，the supporting pressure of the elastic area(kPa)，the maximum stress concentration coefficient，the width of t

13、he plastic area(m)，H the buried depth of the coal floor(m)，the width of the area affected by the supporting pressure(m) and is the average weight of the volume of the over-lying strata (kN/m3) 3.2Stress calculation processAccording to the theory of elasticity on distributed loads on a semi-infinite

14、plane，we can use Eq.(2) to calculate the vertical stresses z(1) and z(2) and the horizontal stresses x(1) and x(2) which are affected by the supporting pressures and The stress equations at point M(x, z) can then be obtained correspondingly by superposition (this calculation neglects the effect of t

15、he transferred load from the goaf and the overlying strata movement as well as the effect of the initial ground stress because it does not produce subsidiary stress at point M；largely we considered the action of the supporting pressure in front of the working face). The calculations are as follows：T

16、herefore，z = z(1) + z(2) (4) and x = x(1) + x(2) (5). By coordinate transformation(x = x (n = 0，1，2，)，x is regarded as x0 in Eqs.(4) and (5) and the stress values of each section can be calculated，where the variable expresses the relative distance from the pushing position of the working face to the

17、 origin of the coordinate system. Given the related parameters of supporting pressures，the stress values，located at the relatively fixed floor section，(x =) at different depths，can be calculated by computer when the working faces advance.When x = x，Eqs.(4) and (5) can be represented as follows：3.3Ex

18、ample analysis Given the actual geological conditions and mining technology at the 2702 working face of the Yangcun Colliery of the Yanzhou Mining Group Limited Company，the following related parameters are determined：=3，=5 m，=50 m，=25 kN/m3 and H=500 m.Using Eqs.(6) and (7)，the stress distribution c

19、urves are obtained on the relatively fixed floor section x= at different depths with the working face advancing by calculation. The results are shown means of computer in Figs. 3 and 4.Fig. 3 shows that vertical stress maintains its maximum at the interface between the coal seam and floor on the sec

20、tion x=from the original coordinates and then quickly decreases with the increasing depth and slowly decreases at a specific depth. A similar situation is obtained when the working face advances，i.e.，the range of the vertical stress decreases with an increase in depth. From the results it can be see

21、n that the range of depth, given the variation of vertical stress, is relatively large, i.e., within 40 m. The range of the vertical stress is clearly smaller after the working face advances 30 m. According to the relationship of the variation between vertical and horizontal stress, the multiplicati

22、on of the variation of vertical stress and its corresponding coefficient of horizontal pressure () is equal to the increment of horizontal stress at the point M1. Then the increment of horizontal stress and the horizontal stress at the point M continues to be superposed, which is inversed analysis w

23、hen the working face advances 30 m. The results of the variation in stress show that the vertical stress is larger than the horizontal stress when the working face is at its original position: the maximum principal stress is the vertical stress; the minimum principal stress is horizontal stress. Bec

24、ause the rate of decrease of the vertical stress is faster than the horizontal stress, the horizontal stress is larger than the vertical stress within 42 m when the working face advances 30 m (for details, see Fig. 4). Considering the effect of the variation in vertical stress, the horizontal stress

25、 is much larger than the vertical stress. The maximum principal stress is the horizontal stress and the minimum principal stress is the vertical stress. It agrees with the partial reasons of the mechanical principle of floor heave12-14.Fig. 3 also shows that the variation is almost steady on the sec

26、tion x= when the working face advances 30 m. Therefore, the relationship of variation in stress with depth is calculated when the working face advances from 0 to 30 m. The details are shown in Table 1.Table 1 Data of rock characteristics and correlative stress of the floor on 2702 working face in Ya

27、ngcun colliery (MPa)岩层深度(m)x=0 mx=30 mx=30 mx=30 m泥岩037.500.000.000.0037.500.4316.1316.13527.250.042.122.0827.2111.7013.78砂岩1022.530.283.833.5522.250.327.1210.671519.950.774.914.1419.186.1410.282118.171.465.403.9416.715.359.29石灰岩2516.752.215.463.2514.540.284.077.322815.552.945.242.3012.613.535.83Fro

28、m the analysis of the related data, the stresses + in Table 1 can be regarded as the stress values，obtained from mechanical rock tests. So the variations of the principal stress from theoretical calculations and the results from the servo-controlled tests can be contrasted. Given these contrasts it

29、is seen that, the largest stress value of mudstoneis 16.13 MPa and the largest stress value of sandstone10.67 MPa. When combining Fig. 5 with Table 1 it is seen that, the largest calculated principal stress is less than the peak value of the principal stress in Fig. 5, and the calculated section is

30、at an elastic deformation section of Fig. 5, where permeability is relatively weak. So there is still a certain ability of water resistance. It can be shown that the obvious destruction is not produced in the mudstone and sandstone when the working face advances 30 m. This is essentially consistent

31、with the conclusions of the survey report.4 Conclusions 1) Based on the mechanical model of the floor, the analysis of stress distribution is obtained on the relatively fixed floor position with an advancing of working face. Owing to heterogeneity and discontinuity of the rock mass of the coal floor

32、, there is a certain divergence between the ideal model and actual conditions. But from analyses and calculations, the basic variation law of stress distribution is discovered on the relatively fixed floor position with an advancing of working face when specific parameters are given for the working

33、face. 2) The decreasing rate of the vertical stress is faster than that of the horizontal stress up to a certain depth and the direction of the maximum principal stress is changed from vertical at the original position to horizontal with an advancing of the working face. The horizontal stress is lar

34、ger than vertical stress within 42 m when the working face advances 30 m. 3) The difference between the theoretically calculated principal stress and the results of the servo-controlled penetrability test can be contrasted. Deformation and penetrability can be obtained from the floor rock mass. From

35、 an example, it is seen that the mudstone and sandstone of coal floor are at an elastic deformation stage. There is no extreme destruction on the relatively fixed floor section with an advancing of working face and there still is a certain ability of water resistanceAcknowledgements Here we express

36、our sincere appreciation to director for Zhao Zhenzhong, minister Song Shun of Zhengzhou Coal Industry Group for their help during the course of the sampling. Appreciating Dr. Xi Yantao of China University of Mining and Technology for his help for modification.References：1 Zhang J C, Zhang Y Z, Liu

37、T Q. Rock Mass Permeability and Coal Mine Water Inrush.Beijing: Geological Publishing House, 1997. (In Chinese)2 Miao X X, Lu A H, Mao X B, et al. Numerical simulation for roadways in swelling rock under coupling function of water and ground pressure. Journal of China University ofMining and Technol

38、ogy, 2002, 12(2): 120-125.3 Gong P L, Hu Y Q, Zhao Y S, et al. Three-dimensional simulation study on law of deformation and breakage of coal floor on mining above aquifer. Chinese Journal of Rock Mechanics and Engineering, 2005, 24(23): 4396-4402. (In Chinese)4 Shi L Q, Han J. Floor Water-Inrush Mec

39、hanism and Prediction. Xuzhou: China University of Mining and Technology Press, 2004. (In Chinese)5 Jing H W, Xu G A, Ma S Z. Numerical analysis on displacement law of discontinuous rock mass in broken rock zone for deep roadway. Journal of China University of Mining and Technology, 2001, 11(2): 132

40、-137.6 Liu Y D, Zhang D S, Wang Ii S, et al. Simulation analysis of coal mining with top-coal caving under hard-and-thick strata. Journal of China University of Mining and Technology, 2006, 16(2): 110-114.7 Dun Z L, Gao J M. Mechanics of Elasticity and Its Application in Geotechnical Engineering. Be

41、ijing: China Coal Industry Publishing House, 2003. (In Chinese)8 Xu Z L. A Concise Course in Elasticity. Beijing: Higher Education Press, 2002. (In Chinese)9 Liu W Q, Miao X X. Numerical analysis of finite deformation of overbroken rock mass in gob area based on Euler model of control volume. Journa

42、l of China University of Mining and Technology, 2006, 16(3): 245-248.10 Jiang F X. Rock Pressure and Stress Control. Beijing: China Coal Industry Publishing House, 2004. (In Chinese)11 Qian M G, Shi P W. Rock Pressure and Stress Control. Xuzhou: China University of Mining and Technology Press, 2003.

43、 (In Chinese)12 Xu N Z, Tu M. The mechanism and control of floor heave of road driving along next goaf of high seam. Journal of Anhui University of Science and Technology (Natural Science), 2004, 24(2): 1-4. (In Chinese)I3 Wang W J, Hou C J. Study of mechanical principle of floor heave of roadway dr

44、iving along next goaf in fully mechanized sub-level caving face. Journal of Coal Science and Engineering, 2001, 7(1): 13-17.14 Zhai X X, Li D Q, Shao Q, et al. Control over surrounding rocks deformation of soft floor and whole-coal gateways with trapezoidal supports. Journal of China University of M

45、ining and Technology, 2005, 15(2): 118-123.中文译文：采场底板岩层应力的分析模型及应用 摘要：在分析矿山压力的基础上，运用弹性理论建立了煤层底板应力分析计算模型。该模型对煤层底板随工作面推进相对固定位置剖面处应力分布规律进行了求解：煤层某相对固定位置底板应力沿深度变化幅度越来越小，在一定深度范围内垂直应力的释放速度远大于水平应力的释放速度，随着工作面推进，最大主应力的方向由开始的垂直方向变为后来的水平方向。通过比较由试验得到的渗透率-应变关系和根据应力应变曲线理论计算的主应力两者的不同得到煤层底板岩块的变形量和渗透性。这为防治带压开采时煤层底板突水提供

46、了重要的理论依据。关键词：模型；煤层底板；应力分布；解析法1 引言煤层开采之后，受采动影响，煤层顶底板岩层的应力场将发生变化，应力要进行重新分布，其结果必将造成顶底板岩层产生变形、位移甚至破坏，直至达到新的应力平衡1。随着煤矿向深部开采，底板应力分布规律的研究对掌握底板岩层变形及破坏特征、预测底板突水和设计底板巷道的合理位置与维护方法等方而都具有非常重要的实际意义。目前关于工作面底板岩层应力分布规律的研究，一般大多数是靠有限元数值计算和相似材料模拟实验2-6，本文尝试在弹性力学的基础上，应用解析的方法对回采工作面采后底板岩层相对固定位置处应力的分布进行了初步探讨，并结合现场实际资料进行了应用。

47、2 基本原理假设半无限平面受有均布载荷，运用弹性理论通过叠加原理得到应力分布公式7-8。如图1所示，设半平面体在其边界的AB段上受有强度为q(x)的铅直分布载荷。为求出半平面体内某一点例如M点处的应力状态。令M点的坐标为(x，z)，在AB段上距离坐标原点O为处取一微小长度d，将其上所受的力dp=qd看作一个微小集中力，该微小集中力在M点形成的应力状态可用下式来表达。为求出全部分布载荷对M点的作用，只需将所有各个微小集中力引起的应力相叠加，亦即求出式(1)从= -a 到 = b的积分。3 煤层底板应力计算3.1力学模型的建立根据矿山压力理论，回采工作面前方支撑压力分布力学模型可简化为如图2所示9

48、-11。其中OA段为塑性区，长度设为x0，AB 段为弹性区，长度设为L0x0。为便于计算并不失其内在本质，可假设两段支撑压力均呈线性变化，则可得：式中：为塑性区支撑压力，kPa；为弹性区支撑压力，kPa； 为最大集中应力系数；为塑性区宽度，m；H为煤层底板埋深，m；为支撑压力影响区宽度，m；为上覆岩层平均容重，kN/m3。3.2应力计算过程 根据弹性力学中半无限平面边界上受分布载荷作用的问题，利用式(2)则可分别计算出支承压力 对底板下一点M(x, z) 产生的垂直应力z(1)，z(2) 和水平应力 x(1)，x(2)。然后再分别对应相加即可得到点M(x, z)处的应力表达式(此计算忽略采空区垮落岩石及上覆岩层移动下沉传递载荷的影响，也忽略了原岩应力的影响，因为它