土木 地质 岩土工程专业毕业英文翻译原文和译文
Failure Properties of Fractured Rock Masses as Anisotropic
Homogenized Media
Introduction
It is commonly acknowledged that rock masses always display discontinuous surfaces of various sizes and orientations, usually referred to as fractures or joints. Since the latter have much poorer mechanical characteristics than the rock material, they play a decisive role in the overall behavior of rock structures,whose deformation as well as failure patterns are mainly governed by those of the joints. It follows that, from a geomechanical engineering standpoint, design methods of structures involving jointed rock masses, must absolutely account for such ‘‘weakness’’ surfaces in their analysis.
The most straightforward way of dealing with this situation is to treat the jointed rock mass as an assemblage of pieces of intact rock material in mutual interaction through the separating joint interfaces. Many design-oriented methods relating to this kind of approach have been developed in the past decades, among them,the well-known ‘‘block theory,’’ which attempts to identify poten-
tially unstable lumps of rock from geometrical and kinematical considerations (Goodman and Shi 1985; Warburton 1987; Goodman 1995). One should also quote the widely used distinct element method, originating from the works of Cundall and coauthors (Cundall and Strack 1979; Cundall 1988), which makes use of an explicit ?nite-difference numerical scheme for computing the displacements of the blocks considered as rigid or deformable bodies. In this context, attention is primarily focused on the formulation of realistic models for describing the joint behavior.
Since the previously mentioned direct approach is becoming highly complex, and then numerically untractable, as soon as a very large number of blocks is involved, it seems advisable to look for alternative methods such as those derived from the concept of homogenization. Actually, such a concept is already partially conveyed in an empirical fashion by the famous Hoek and Brown’s criterion (Hoek and Brown 1980; Hoek 1983). It stems from the intuitive idea that from a macroscopic point of view, a rock mass intersected by a regular network of joint surfaces, may be perceived as a homogeneous continuum. Furthermore, owing to the existence of joint preferential orientations, one should expect such a homogenized material to exhibit anisotropic properties.
The objective of the present paper is to derive a rigorous formulation for the failure criterion of a jointed rock mass as a homogenized medium, from the knowledge of the joints and rock material respective criteria. In the particular situation where twomutually orthogonal joint sets are considered, a closed-form expression is obtained, giving clear evidence of the related strength anisotropy. A comparison is performed on an illustrative example between the results produced by the homogenization method,making use of the previously determined criterion, and those obtained by means of a computer code based on the distinct element method. It is shown that, while both methods lead to almost identical results for a densely fractured rock mass, a ‘‘size’’ or ‘‘scale effect’’ is observed in the case of a limited number of joints. The second part of the paper is then devoted to proposing a method which attempts to capture such a scale effect, while still taking advantage of a homogenization technique. This is
achieved by resorting to a micropolar or Cosserat continuum description of the fractured rock mass, through the derivation of a generalized macroscopic failure condition expressed in terms of stresses and couple stresses. The implementation of this model is ?nally illustrated on a simple example, showing how it may actually account for such a scale effect.
Problem Statement and Principle of Homogenization Approach
The problem under consideration is that of a foundation (bridge pier or abutment) resting upon a fractured bedrock (Fig. 1), whose bearing
capacity needs to be evaluated from the knowledge of the strength capacities of the rock matrix and the joint interfaces. The failure condition of the former will be expressed through the classical Mohr-Coulomb condition expressed by means of the cohesion
C and the
m
. Note that tensile stresses will be counted positive throughout the paper. friction angle
m
Likewise, the joints will be modeled as plane interfaces (represented by lines in the ?gure’s plane). Their strength properties are described by means of a condition involving the stress vector of components (σ, τ) acting at any point of those interfaces
According to the yield design (or limit analysis) reasoning, the above structure will remain safe under a given vertical load Q(force per unit length along the Oz axis), if one can exhibit throughout the rock mass a stress distribution which satis?es the equilibrium equations along with the stress boundary conditions,while complying with the strength requirement expressed at any point of the structure.
This problem amounts to evaluating the ultimate load Q﹢beyond which failure will occur, or equivalently within which its stability is ensured. Due to the strong heterogeneity of the jointed rock mass, insurmountable dif?culties are likely to arise when trying to implement the above reasoning directly. As regards, for instance, the case where the strength properties of the joints are considerably lower than those of the rock matrix, the implementation of a kinematic approach would require the use of failure mechanisms involving velocity jumps
across the joints, since the latter would constitute preferential zones for the occurrence of
failure. Indeed, such a direct approach which is applied in most classical design methods, is becoming rapidly complex as the density of joints increases, that is as the typical joint spacing l is becoming small in comparison with a characteristic length of the structure such as the foundation width B.
In such a situation, the use of an alternative approach based on the idea of homogenization and related concept of macroscopic equivalent continuum for the jointed rock mass, may be appropriate for dealing with such a problem. More details about this theory, applied in the context of reinforced soil and rock mechanics, will be found in (de Buhan et al. 1989; de Buhan and Salenc ,on 1990; Bernaud et al. 1995).
Macroscopic Failure Condition for Jointed Rock Mass
The formulation of the macroscopic failure condition of a jointed rock mass may be obtained from the solution of an auxiliary yield design boundary-value problem attached to a unit representative cell of jointed rock (Bekaert and Maghous 1996; Maghous et al.1998). It will now be explicitly formulated in the particular situation of two mutually orthogonal sets of joints under plane strain conditions. Referring to an orthonormal frame O 21ξξwhose axes are placed along the joints directions, and introducing the following change of stress variables:
such a macroscopic failure condition simply becomes
wh
ere it will be assumed that
A convenient representation of the macroscopic criterion is to draw the strength envelope relating to an oriented facet of the homogenized material, whose unit normal n I is inclined by an angle a with respect to the joint direction. Denoting by n σ and n τthe normal and shear components of the stress vector acting upon such a facet, it is possible to determine for any value of a the set of admissible stresses (n σ , n τ) deduced from conditions (3) expressed in terms of (11σ,22σ , 12σ). The corresponding domain has been drawn in Fig. 2 in the
particular case where m ?α≤ .
Two comments are worth being made:
1. The decrease in strength of a rock material due to the presence of joints is clearly illustrated by Fig.
2. The usual strength envelope corresponding to the rock matrix failure condition is ‘‘truncated’’ by two orthogonal semilines as soon as condition m j H H is ful?lled.
2. The macroscopic anisotropy is also quite apparent, since for instance the strength envelope drawn in Fig. 2 is dependent on the facet orientation a. The usual notion of intrinsic curve should therefore be discarded, but also the concepts of anisotropic cohesion and friction angle as tentatively introduced by Jaeger (1960), or Mc Lamore and Gray (1967).
Nor can such an anisotropy be properly described by means of criteria based on an extension of the classical Mohr-Coulomb condition using the concept of anisotropy tensor(Boehler and Sawczuk 1977; Nova 1980; Allirot and Bochler1981).
Application to Stability of Jointed Rock Excavation
The closed-form expression (3) obtained for the macroscopic failure condition, makes it then possible to perform the failure design of any structure built in such a material, such as the excavation shown in Fig. 3,
where h and β denote the excavation height and the slope angle, respectively. Since no
surcharge is applied to the structure, the speci?c weight γ of the constituent material will obviously constitute the sole loading parameter of the system.Assessing the stability of this structure will amount to evaluating the maximum possible height h+ beyond which failure will occur. A standard dimensional analysis of this problem shows that this critical height may be put in the form
where θ=joint orientation and K+=nondimensional factor governing the stability of the excavation. Upper-bound estimates of this factor will now be determined by means of the yield design kinematic approach, using two kinds of failure mechanisms shown in Fig. 4.
Rotational Failure Mechanism [Fig. 4(a)]
The ?rst class of failure mechanisms considered in the analysis is a direct transposition of those usually employed for homogeneous and isotropic soil or rock slopes. In such a mechanism a volume of homogenized jointed rock mass is rotating about a point Ω with an angular velocity ω. The curve separating this volume from the rest of the structure which is
and kept motionless is a velocity jump line. Since it is an arc of the log spiral of angle
m focus Ω the velocity discontinuity at an y point of this line is inclined at angle wm with respect to the tangent at the same point.
The work done by the external forces and the maximum resisting work developed in such a mechanism may be written as (see Chen and Liu 1990; Maghous et al. 1998)
where e w and me w =dimensionless functions, and μ1 and μ2=angles specifying the position of the center of rotation Ω.Since the kinematic approach of yield design states that a necessary condition for the structure to be stable writes
it follows from Eqs. (5) and (6) that the best upper-bound estimate derived from this ?rst class of mechanism is obtained by minimization with respect to μ1 and μ2
which may be determined numerically.
Piecewise Rigid-Block Failure Mechanism [Fig. 4(b)]
The second class of failure mechanisms involves two translating blocks of homogenized material. It is de?ned by ?ve angular parameters. In order to avoid any misinterpretation, it should be speci?ed that the terminology of block does not refer here to the lumps of rock matrix in the initial structure, but merely means that, in the framework of the yield design kinematic approach, a wedge of homogenized jointed rock mass is given a (virtual) rigid-body motion.
The implementation of the upper-bound kinematic approach,making use of of this second class of failure mechanism, leads to the following results.
where U represents the norm of the velocity of the lower block. Hence, the following upper-bound estimate for K +:
Results and Comparison with Direct Calculation The optimal bound has been computed numerically for the following set of parameters:
The result obtained from the homogenization approach can then be compared with that derived from a direct calculation, using the UDEC computer software (Hart et al. 1988). Since the latter can handle situations where the position of each individual joint is speci?ed, a series of calculations has been performed varying the number n of regularly spaced joints, inclined at the same angleθ=10° with the horizontal, and intersecting the facing of the excavation, as
sketched in Fig. 5. The
corresponding estimates of the stability factor have been plotted against n in the same ?gure. It can be observed that these numerical estimates decrease with the number of intersecting joints down to the estimate produced by the homogenization approach. The observed discrepancy between homogenization and direct approaches, could be regarded as a ‘‘size’’ or ‘‘scale effect’’ which is not included in the classical
homogenization model. A possible way to overcome such a limitation of the latter, while still taking advantage of the homogenization concept as a computational time-saving alternative for design purposes, could be to resort to a description of the fractured rock medium as a Cosserat or micropolar continuum, as advocated for instance by Biot (1967); Besdo(1985); Adhikary a nd Dyskin (1997); and Sulem and Mulhaus (1997) for strati?ed or block structures. The second part of this paper is devoted to applying such a model to describing the failure properties of jointed rock media.
均质各向异性裂隙岩体的破坏特性
概述
由于岩体表面的裂隙或节理大小与倾向不同，人们通常把岩体看做是非连续的。尽管裂隙或节理表现出的力学性质要远远低于岩体本身，但是它们在岩体结构性质方面起着重要的作用，岩体本身的变形和破坏模式也主要是由这些节理所决定的。从地质力学工程角度而言，在涉及到节理岩体结构的设计方法中，软弱表面是一个很重要的考虑因素。
解决这种问题最简单的方法就是把岩体看作是许多完整岩块的集合，这些岩块之间有很多相交的节理面。这种方法在过去的几十年中被设计者们广泛采用，其中比较著名的是“块体理论”，该理论试图从几何学和运动学的角度用来判别潜在的不稳定岩块（Goodman & 石根华1985；Warburton 1987；Goodman 1995）；另外一种广泛使用的方法是特殊单元法，它是由Cundall及其合作者（Cundall & Strack 1979；Cundall 1988）提出来的，其目的是用来求解显式有限差分数值问题，计算刚性块体或柔性块体的位移。本文的重点是阐述如何利用公式来描述实际的节理模型。
既然直接求解的方法很复杂，数值分析方法也很难驾驭，同时由于涉及到了数目如此之多的块体，所以寻求利用均质化的方法是一个明智的选择。事实上，这个概念早在Hoek-Brown准则（Hoek & Brown 1980；Hoek 1983）得出的一个经验公式中就有所涉及，它来自于宏观上的一个直觉，被一个规则的表面节理网络所分割的岩体，可以看做是一个均质的连续体，由于节理倾向的不同，这样的一个均质材料显示出了各向异性的性质。
本文的目的就是：从节理和岩体各自准则出发，推求出一个严格准确的公式，来描述作为均匀介质的节理岩体的破坏准则。先考查特殊情况，从两组相互正交的节理着手，得到一个封闭的表达式，清楚的证明了强度的各向异性。我们进行了一项试验：把利用均质化方法得到的结果和以前普遍使用的准则得到的结果以及基于计算机编程的特殊单元法（DEM）得到的结果进行了对比，结果表明：对于密集裂隙的岩体，结果基本一致；对于节理数目较少的岩体，存在一个尺寸效应（或者称为比例效应）。本文的第二部分就是在保证均质化方法优点的前提下，致力于提出一个新的方法来解决这种尺寸效应，基于应力和应力耦合的宏观破坏条件，提出利用微极模型或者Cosserat连续模型来描述节理岩体；最后将会用一个简单的例子来演示如何应用这个模型来解决比例效应的问题。
问题的陈述和均质化方法的原理
考虑这样一个问题：一个基础（桥墩或者其邻接处）建立在一个有裂隙的岩床上
（Fig.1），岩床的承载能力通过岩基和节理交界面的强度
估算出来。岩基的破坏条件使用传统的莫尔-库伦条件，可以用粘聚力C 1和内摩擦角? m 来表示（本文中张应力采用正值计算）。同样，用接触平面代替节理（图示平面中用直线表示）。强度特性采用接触面上任意点的应力向量(σ,τ)表示：
根据屈服设计（或极限分析）推断，如果沿着应力边界条件，岩体应力分布满足平
衡方程和结构任意点的强度要求，那么在一个给定的竖向荷载Q（沿着OZ 轴方向）作
用下，上部结构仍然安全。
这个问题可以归结为求解破坏发生处的极限承载力Q+，或者是多大外力作用下结构能确保稳定。由于节理岩体强度的各向异性，若试图使用上述直接推求的方法，难度就会增大很多。比如，由于节理强度特性远远低于岩基，从运动学角度出发的方法要求考虑到破坏机理，这就牵涉到了节理上的速度突跃，而节理处将会是首先发生破坏的区域。
这种应用在大多数传统设计中的直接方法，随着节理密度的增加越来越复杂。确切
地说，这是因为相比较结构的长度（如基础宽B）而言，典型节理间距L变得更小，加
大了问题的难度。在这种情况下，对节理岩体使用均质化方法和宏观等效连续的相关概
念来处理可能就会比较妥当。关于这个理论的更多细节，在有关于加固岩土力学的文章
中可以查到（de Buhan等1989；de Buhan & Salenc 1990；Bernaud等1995）。
节理岩体的宏观破坏条件
节理岩体的宏观破坏条件公式可以从对节理岩体典型晶胞单元的辅助屈服设计边值问题中得到（Bekaert & Maghous 1996; Maghous 等 1998）。现在可以精确地表示平面应变条件下，两组相互正交节理的特殊情况，建立沿节理方向的正交坐标系O 21ξξ ，并引入下列应力变量：
宏
观破坏条件可简化为：
其中，假定
宏观准则的一种简便表示方法是画出均质材料倾向面上的强度包络线，其单位法线n 的倾角α 为节理的方向，分别用σn 和τn 表示这个面上的正应力和切应力，用(11σ,22σ , 12σ) 表示条件（3），推求出一组许可应力(σn ,τn ),然后求解出倾角α 。当α ≥? m 时，相应的区域表示如图2所示，并对此做出两个注解如下：
1. 从图2中可以清楚的看出，节理的存在导致了岩体强度的降低。通常当m j H H <时，强度包络线和岩基破坏条件相一致，其前半部分被两个正交的半条线切去。
2. 宏观各向异性很显著。比如，图2中的强度包络线决定于方位角α 。应该抛弃
固有曲线和各向异性粘聚力与摩擦角的概念，其中后一个概念是由Jaeger（1960）或Mc Lamore & Gray（1967）所引入的。通过莫尔-库伦条件进行扩展，利用各向异性张量的方法来描述各向异性也是不妥当的(Boehler & Sawczuk 1977；Nova 1980；Allirot & Bochler 1981) 。
在节理岩体开挖稳定性中的应用
式（3）的封闭形式是从宏观破坏条件中得到的，该式可以用来对此种材料的结构体进行破坏设计，如图3所示的开挖，h 和β分别表示开挖高度和边坡
角。由于结构上没有其他荷载，材料比重γ就成为系统唯一的加载参数。该结构的稳定性评价需要在破坏发生的部位算出最大可能高度h+，通过标准量纲分析表明，这个临界高度表示为：
其中θ为节理方位角，K +为表示开挖部位稳定性的一个无量纲因子，该因子的上界估计值可以分别使用图4所示的两种类型的破坏机制，通过屈服设计的运动学方法来确定。
转动破坏机理[Fig. 4(a)]
第一种类型的破坏机制，通常把分析对象直接转换为均匀各向同性的岩坡（或土坡）。若采用这种破坏机制，各向同性的节理岩体围绕点Ω产生角速度为ω的旋转，把静止的部分和运动的部分分开的曲线即为速度突跃线，在这条角度为?m、圆心为Ω
的滑弧上的任意一点上，速度都不是连续的，速度方向与该点处的切线成倾角?m。
在这种破坏机制下，外力所做的功和最大抵抗功可以表示为下列形式（Chen & Liu 1990；Maghous 等。
w e和w mr为无量纲函数，
μ1和μ2为滑移体的圆心角，由于屈服设计状态的动力学方法是结构稳固的一个必要条件，故有：
联立（5）式和（6）式，取μ1和μ2的最小值进行计算，可以得到第一种类型破坏机制的最佳上界估计：
分段刚性块体破坏机理[Fig. 4(b)]
第二种类型的破坏机制涉及到了两种均匀材料块体的转换，由五个角度参数定义。为了避免误解，应该具体指出，“块体”并不是指代初始状态下的岩基块体，在屈服设计运动学方法的框架下，它代表的不仅仅这个意思，一块均质节理岩体的运动可以近似
看做是刚体运动。
对于第二种类型的破坏机制，运用上界运动学方法，可以得出以下结果：（在Fréard
(2000)的文中可以找到详细的计算过程）
其中U 表示下盘块体的速度（如图4-b所示）。因此，K +
上界估计值为：
计算结果以及与直接计算结果之间的对比
经过计算，选定最优上界参数值为：
屈服时有
利用UDEC软件（Hart等1988）对均质化方法的计算结果和直接计算方法的结果进行对比发现，当每一个节理的位置都已知时，利用后一种方法就可以求解这个问题，当节理间隙很规则，且倾角保持在与水平成10 °的方向切割开挖平面时，随着节理数n的变化，计算出一系列的结果，点绘于图5中，与n相应的稳定性因子的估计值也在
图5中表示出来，容易看出，随着分割节理数目的降低，这些估计值
的大小降低到了均质化方法的估计值。均质化方法和直接计算法的差异可以看成是由于“尺寸效应”而引起的，而均质化方法并没有尺寸效应的问题。为了设计上计算的省时高效，克服直接计算法的局限，同时要运用均质化的概念，考虑对裂隙岩体介质采用一种新的描述方法——Cosserat 或者是微极连续，Biot (1967)，Besdo (1985)，Adhikary & Dyskin (1997)，以及Sulem & Mulhaus (1997) 对于分层岩体或者是块体结构都有所描述。本文的第二部分就是致力于应用这个模型来描述节理岩体介质的破坏特性。
英语原文及其翻译
Exploring Filipino School Counselors’ Beliefs about Learning Allan B. I. Bernardo [Abstract] School reform efforts that focus on student learning require school counselors to take on important new roles as advocates of student learning and achievement.But how do school counselors understand the process of learning? In this study, we explore the learning beliefs of 115 Filipino school counselors who indicated their degree of agreementwith 42 statements about the process of learning and the factors thatinfluence this process.A principal components analysis of the responses to the 42 statements suggested three factors:(F1)social-cognitive constructivist beliefs, (F2) teacher-curriculum-centered behaviorist beliefs,and (F3) individual difference factors.The preliminary results are briefly discussed in terms of issues related to how Filipino school counselors’ conceptions of learning may guide their strategies for promoting student learning and achievement. [Key words]beliefs about learning, conceptions of learning, school counselors, student learning, Philippines School reform efforts in different parts of the world have focusedon students’learning. In particular,most school improvement programsnow aim to ensure that students acquire the high-level knowledge and skills that help them to thrive in today’s highly competitive globaleconomy (e.g., Lee & Williams, 2006). I n this regard, school reform programs draw from various contemporary theories and research on learning (e.g.,Bransford,Brown, & Cocking, 1999; Lambert & McCombs, 1998).The basic idea is that all school improvement efforts should be directed at ensuring students achieve high levels of learning or attainment of well-defined curricular objectives and standards.For example, textbooks (Chien & Young, 2007), computers and educational technology (Gravoso, 2002; Haertnel & Means, 2003;Technology in Schools Task Force, 2003), and educational assessment systems (Black & Wiliam2004; Cheung & Ng, 2007; Clark, 2001; Stiggins, 2005) are being reconsidered as regards how they can effectively provide scaffolds and resources for advancing student learning. Likewise,the allocation and management of a school’s financial resources are assessed in terms ofwhether these are effectively mobilized and utilized towards improving student learning (Bolam, 2006; Chung & Hung, 2006; Retna, 2007). In this regard, some advocates have also called for an examination of the role of school counselors in these reform efforts (Herr, 2002). Inthe United States, House and Hayes (2002) challenged school counselors to take proactive leadership roles in advocating for the success of all
蓝梅主编 给排水科学与工程专业英语部分课文翻译中文版
第四单元给水系统 一般来说，供水系统可划分为四个主要组成部分:（1）水源和取水工程（2）水处理和存储（3）输水干管和配水管网。常见的未处理的水或者说是原水的来源是像河流、湖泊、泉水、人造水库之类的地表水源以及像岩洞和水井之类的地下水源。修建取水构筑物和泵站是为了从这些水源中取水。原水通过输水干管输送到自来水厂进行处理并且处理后的出水储存到清水池。处理的程度取决于原水的水质和出水水质要求。有时候，地下水的水质是如此的好以至于在供给给用户之前只需消毒即可。由于自来水厂一般是根据平均日需求流量设计的，所以，清水池为水需求日变化量提供了一个缓冲区。 水通过输水干管长距离输送。如果输水干管中的水流是通过泵所产生的压力水头维持的，那么我们称这个干管为增压管。另外，如果输水干管中的水流是靠由于高差产生的可获得的重力势能维持的，那么我们称这个干管为重力管。在输水干管中没有中间取水。与输水干管类似，在配水管网中水流的维持要么靠泵增压，要么靠重力势能。一般来说，在平坦地区，大的配水管网中的水压是靠泵提供的，然而，在不平坦的地区，配水管网中的压力水头是靠重力势能维持的。 一个配水管网通过引入管连接配水给用户。这样的配水管网可能有不同的形状，并且这些形状取决于这个地区的布局。一般地，配水管网有环状或枝状的管道结构，但是，根据当地城市道路和街区总体布局计划，有时候环状和枝状结构合用。城市配水管网大多上是环状形式，然而，乡村地区的管网是枝状形式。由于供水服务可靠性要求高，环状管网优于枝状管网。 配水管网的成本取决于对管网的几何形状合适的选择。城市计划采用的街道布局的选择对提供一个最小成本的供水系统来说是重要的。环状管网最常见的两个供水结构是方格状、环状和辐射状；然而，我们不可能找到一个最佳的几何形状而使得成本最低。 一般地，城镇供水系统是单入口环状管系统。如上所说，环状系统有一些通过系统相互连接的管道使得通过这些连接接的管道，可以供水到同一个需水点。与枝状系统不同，在环状系统中，由于需水量在空间和时间上的变化，管道中的水流方向并非不变。 环状管网可为系统提供余量，提高系统应对局部变化的能力，并且保证管道故障时为用户供水。从水质方面来说，环状形状可减少水龄，因此被推广。管道的尺寸和配水系统的设计对减少水龄来说是重要的因素。由于多方向水流模式和系统中流动模式随时间的变化，水不会停留在一个地方，这样减少了水龄。环状配水系统的优缺点如表4.1所述。 优点:1.Minimize loss of services.as main breaks can be isolated due to multidirectional flow to demand points.2.Reliability for fire protection is higher due to redundancy in the system.3.Likely to meet increase in water demand -higher capacity and lower velocities.4.Better residual chlorine due to in line mixing and fewer dead ends. 5.Reduced water age. 在文献中曾记载过，只考虑最低成本设计的环状管网系统会转化成树状似的结构，这一做法导致在最终的设计中失去最初的几何形状。环状保证了系统的可靠性。因此，一个只考虑最低成本为依据的设计打败了在环状管网中所提供的基本功能。有文献记载设计环状管网系统的方法。尽管这个方法也是仅以考虑最低成本为基础，它通过对管网中所有管道最优化规划从而保持了管网的环状结构。
土木工程专业英语翻译
a common way to construct steel truss and prestressed concrete cantilever spans is to counterbalance each cantilever arm with another cantilever arm projecting the opposite direction,forming a balanced cantilever. they attach to a solid foundation ,the counterbalancing arms are called anchor arms /thus,in a bridge built on two foundation piers,there are four cantilever arms ,two which span the obstacle,and two anchor arms which extend away from the obstacle,because of the need for more strength at the balanced cantilever's supports ,the bridge superstructure often takes the form of towers above the foundation piers .the commodore barry bridge is an example of this type of cantilever bridge 一种常见的方法构造钢桁架和预应力混凝土悬臂跨度是每一个悬臂抗衡预测相反的方向臂悬臂，形成一个平衡的悬臂。他们重视了坚实的基础，制约武器被称为锚武器/因此，在两个基础上建一座桥桥墩，有四个悬臂式武器，这两者之间跨越的障碍，和两个锚武器哪个延长距离的障碍，因为为更多的在平衡悬臂的支持力量的需要，桥梁上部结构往往表现为塔墩基础之上形成的准将巴里大桥是这种类型的例子悬臂桥 steel truss cantilever support loads by tension of the upper members and compression of the lower ones .commonly ,the structure distributes teh tension via teh anchor arms to the outermost supports ,while the compression is carried to the foundation beneath teh central towers .many truss cantilever bridges use pinned joints and are therefore statically determinate with no members carrying mixed loads 钢桁架悬臂由上层成员和下层的紧张压缩支持负载。通常，结构分布通过锚武器的最外层的支持紧张，而压缩抬到下方的中央塔的基础。桁架悬臂许多桥梁使用固定的关节，是静定，没有携带混合负载的成员，因此 prestressed concrete balanced cantilever bridges are often built using segmental construction .some steel arch bridges are built using pure cantilever spans from each sides,with neither falsework below nor temporary supporting towers and cables above ,these are then joined with a pin,usually after forcing the union point apart ,and when jacks are removed and the bridge decking is added the bridge becomes a truss arch bridge .such unsupported construction is only possible where appropriate rock is available to support the tension in teh upper chord of the span during construction ,usually limiting this method to the spanning of narrow canyons 预应力混凝土平衡悬臂桥梁往往建立使用段施工。一些钢拱桥是使用各方面的纯悬臂跨度既无假工作下面也临时支撑塔和电缆上面，这些都是再加入了一根针，通常在迫使工会点外，当插孔删除，并添加桥梁甲板桥成为桁架拱桥，这种不支持的建设，才可能在适当情况下的岩石可用于支持在施工期间的跨度弦上的张力，通常限制这狭隘的峡谷跨越方法 an arch bridge is a bridge with abutments at each end shaped as a curved arch .arch bridges work by transferring the weight of the bridge and its loads partially into a horizontal thrust restrained by the abutments at either side .a viaduct may be made from a series of arches ,although other more economical structures are typically used today 在拱桥桥台的桥梁，是一个在一个弧形拱状，每年年底。拱桥通过转移到由部分在两边的桥台水平推
(完整版)_毕业设计英文文献51单片机中英文文献翻译_
AT89C51的概况 The General Situation of AT89C51 Chapter 1 The application of AT89C51 Microcontrollers are used in a multitude of commercial applications such as modems, motor-control systems, air conditioner control systems, automotive engine and among others. The domains also require that these microcontrollers are be ensured by a robust testing process and a proper tools environment for the validation of these microcontrollers both at the component and at the system level. Intel Plaform Engineering department developed an object-oriented multi-threaded test environment for the validation of its AT89C51 automotive microcontrollers. The goals of thisenvironment was not only to provide a robust testing environment for the AT89C51 automotive microcontrollers, but to develop an environment which can be easily extended and reused for the validation of several other future microcontrollers. The environment was developed in conjunction with Microsoft Foundation Classes (AT89C51). The paper describes the design and mechanism of this test environment, its interactions with various The 8-bit AT89C51 CHMOS microcontrollers are designed to engine-control systems, airbags, suspension systems, and antilock braking systems (ABS). The AT89C51 is especially well suited to applications that benefit from its processing speed and enhanced
文献翻译英文原文
https://www.wendangku.net/doc/ab9591957.html,/finance/company/consumer.html Consumer finance company The consumer finance division of the SG group of France has become highly active within India. They plan to offer finance for vehicles and two-wheelers to consumers, aiming to provide close to Rs. 400 billion in India in the next few years of its operations. The SG group is also dealing in stock broking, asset management, investment banking, private banking, information technology and business processing. SG group has ventured into the rapidly growing consumer credit market in India, and have plans to construct a headquarters at Kolkata. The AIG Group has been approved by the RBI to set up a non-banking finance company (NBFC). AIG seeks to introduce its consumer finance and asset management businesses in India. AIG Capital India plans to emphasize credit cards, mortgage financing, consumer durable financing and personal loans. Leading Indian and international concerns like the HSBC, Deutsche Bank, Goldman Sachs, Barclays and HDFC Bank are also waiting to be approved by the Reserve Bank of India to initiate similar operations. AIG is presently involved in insurance and financial services in more than one hundred countries. The affiliates of the AIG Group also provide retirement and asset management services all over the world. Many international companies have been looking at NBFC business because of the growing consumer finance market. Unlike foreign banks, there are no strictures on branch openings for the NBFCs. GE Consumer Finance is a section of General Electric. It is responsible for looking after the retail finance operations. GE Consumer Finance also governs the GE Capital Asia. Outside the United States, GE Consumer Finance performs its operations under the GE Money brand. GE Consumer Finance currently offers financial services in more than fifty countries. The company deals in credit cards, personal finance, mortgages and automobile solutions. It has a client base of more than 118 million customers throughout the world
建筑工程及给排水专业中英文对照翻译
Laminar and Turbulent Flow Observation shows that two entirely different types of fluid flow exist. This was demon- strated by Osborne Reynolds in 1883 through an experiment in which water was discharged from a tank through a glass tube. The rate of flow could be controlled by a valve at the outlet, and a fine filament of dye injected at the entrance to the tube. At low velocities, it was found that the dye filament remained intact throughout the length of the tube, showing that the particles of water moved in parallel lines. This type of flow is known as laminar, viscous or streamline, the particles of fluid moving in an orderly manner and retaining the same relative positions in successive cross- sections. As the velocity in the tube was increased by opening the outlet valve, a point was eventually reached at which the dye filament at first began to oscillate and then broke up so that the colour was diffused over the whole cross-section, showing that the particles of fluid no longer moved in an orderly manner but occupied different relative position in successive cross-sections. This type of flow is known as turbulent and is characterized by continuous small fluctuations in the magnitude and direction of the velocity of the fluid particles, which are accompanied by corresponding small fluctuations of pressure. When the motion of a fluid particle in a stream is disturbed, its inertia
土木工程专业英语原文及翻译
土木工程专业英语原文 及翻译 文档编制序号：[KKIDT-LLE0828-LLETD298-POI08]
08 级土木(1) 班课程考试试卷 考试科目专业英语 考试时间 学生姓名 所在院系土木学院 任课教师 徐州工程学院印制 Stability of Slopes Introduction Translational slips tend to occur where the adjacent stratum is at a relatively shallow depth below the surface of the slope:the failure surface tends to be plane and roughly parallel to the slips usually occur where the adjacent stratum is at greater depth，the failure surface consisting of curved and plane sections． In practice, limiting equilibrium methods are used in the analysis of slope stability. It is considered that failure is on the point of occurring along an assumed or a known failure surface．The shear strength required to maintain a condition of limiting equilibrium is compared with the available shear strength of the soil，giving the average factor of safety along the failure surface．The problem is considered in two dimensions，conditions of plane strain being assumed．It has been shown that a two-dimensional analysis gives a conservative result for a failure on a three-dimensional(dish-shaped) surface． Analysis for the Case of φu =0 This analysis, in terms of total stress，covers the case of a fully saturated clay under undrained conditions, . For the condition immediately after construction．Only moment equilibrium is considered in the analysis．In section, the potential failure surface is assumed to be a circular arc. A trial failure surface(centre O，radius r and length L a where F is the factor of safety with respect to shear strength．Equating moments about O：
软件开发概念和设计方法大学毕业论文外文文献翻译及原文
毕业设计（论文）外文文献翻译 文献、资料中文题目：软件开发概念和设计方法文献、资料英文题目： 文献、资料来源： 文献、资料发表（出版）日期： 院（部）： 专业： 班级： 姓名： 学号： 指导教师： 翻译日期： 2017.02.14
外文资料原文 Software Development Concepts and Design Methodologies During the 1960s, ma inframes and higher level programming languages were applied to man y problems including human resource s yste ms,reservation s yste ms, and manufacturing s yste ms. Computers and software were seen as the cure all for man y bu siness issues were some times applied blindly. S yste ms sometimes failed to solve the problem for which the y were designed for man y reasons including: ?Inability to sufficiently understand complex problems ?Not sufficiently taking into account end-u ser needs, the organizational environ ment, and performance tradeoffs ?Inability to accurately estimate development time and operational costs ?Lack of framework for consistent and regular customer communications At this time, the concept of structured programming, top-down design, stepwise refinement，and modularity e merged. Structured programming is still the most dominant approach to software engineering and is still evo lving. These failures led to the concept of "software engineering" based upon the idea that an engineering-like discipl ine could be applied to software design and develop ment. Software design is a process where the software designer applies techniques and principles to produce a conceptual model that de scribes and defines a solution to a problem. In the beginning, this des ign process has not been well structured and the model does not alwa ys accurately represent the problem of software development. However,design methodologies have been evolving to accommo date changes in technolog y coupled with our increased understanding of development processes. Whereas early desig n methods addressed specific aspects of the
英文翻译(原文)
GRA VITY RETAINING?WALL 1. INTRODUCTION Retaining walls are structures used to provide stability for earth or other material where conditions disallow the mass to assume its natural slope, and are commonly used to hold back or support soilbanks,coal or ore piles, and water. Retaining walls are classified, based on the method of achieving stability, into six principal types (Fig.1). The gravity-wall depends upon its weight, as the name implies, for stability. The cantilever wall is a reinforced-concrete wall that utilizes cantilever action to retain the mass behind the wall from assuming a natural slope. Stability of this wall is partially achieved from the weight of soil on the heel portion of the base slab. A counterfort retaining wall is similar to a cantilever retaining wall, except that it is used where the cantilever is long or for very high pressures behind wall and has counterforts, which tie the wall and base together, built at intervals along the wall to reduce the bending moments and sheers. As indicated in Fig.1c, the counterfort is behind the wall and subjected to tensile forces. A buttressed retaining wall is similar to a counterfort wall, except that the bracing is in front of the wall and is in compression instead of tension. Two other types of walls not considered further are crib walls, which are built-up members of pieces of precast concrete, metal, or timber and are supported by anchor pieces embedded in the soil for stability, and semigravity walls, which are walls intermediate between a true gravity and a cantilever wall. (a)(b)(e)
水文与水资源专业英语文章翻译
3单元 地下水位的高低可在一年内大幅波动，下降和上升后，在干燥的季节，降水期。因此，为了保证连续供水，井应穿透许多米水位以下。当水从井里抽水，它在水面产生抑郁，大致锥形的形状，称为漏斗。如果抽重，水表不仅可以降低周围的好但还可延伸到大面积。这在美国西部的部分是这样的。在这种情况下，可以说，地下水被“开采”。即使抽人立即停止，它可能需要数百年的地下水得到补充。下面的例子说明了这一点： 例如，在干燥的美国西南部，含水层补给是每年只有1英寸深的水的十分之二点位置。在这些地区，这是不寻常的泵两英尺或更多的水用于灌溉和其他用途的每年。在这个简单的例子，如果整个含水层抽水的速度，每年的开采量将相当于120年和十年的补给，泵将1200年积累的水。在泵送期间新补给可以忽略不计。机械问题和经济因素阻止完全脱水的含水层，但原则上是有效的例子。 短期承压是适用于任何情况，地下水位上升，在一个以上的水平，这是最初遇到的。这样的情况发生，两个条件必须满足：（1）水，必须限制在一个含水层，是倾斜的，一端暴露在表面，在那里可以得到水；和（2）防渗层，上面和下面的含水层，必须防止水逃避，这样一层被窃听，被上面的水的重量产生的压力会使水上升。如果没有摩擦，井里的水会上升到顶部的水位。含水层。 自流系统作为管道，将水从很远的偏远地区的充电放电点。这样水倒在威斯康星州中部年前现在是从地面和社区许多英里远，伊利诺斯。在南达科他州这样的系统已经从西部的黑山带水，向东跨越国家。在不同的尺度上，城市供水系统可能是人为的自流系统的例子。水塔，为抽水，可能是补给区，管道的承压含水层，在家中的自流井的水龙头。 4单元 矿产勘查在世界表明温度在深油、矿产品通常会增加在地表以下深度增加。在这样的情况下增加温度约0.6度，平均每30米。因此，当地下水在深循环，它变得激烈，如果它上升到表面，水是温泉。一些温泉水在美国，特别是在东部，加热这种方式。在美国，绝大多数的温泉发现于西方。这种分布的原因是，大部分温泉的热源是冷却的火成岩，它是在西方，火成活动已经最近。 间歇泉是间歇性的温泉或喷泉，水柱喷射的伟大力量在不同的时间间隔，通常上升30-60米。水流停止后，一列蒸汽冲出，通常以雷鸣般的轰鸣声。这或许是世界上最著名的间歇泉是黄石公园的老忠实喷发，大约每小时一次。间歇泉也在世界的其他地区，包括冰岛和新西兰，在那里长期间歇泉，意为“喷泉”或“井喷”这个词。 间歇泉时，地下水是地下室加热。室底部，水在巨大的压力下，由于上覆水的重量。因此，一个100度以上的温度就会沸腾所需的前。例如，在一个300米的室内水下必须达到一个温度近230度才开。加热使水膨胀，其结果是某些流出的顶部。这减少了压力，和水变成蒸汽，使间歇泉喷发。 从温泉和间歇泉地下水通常包含在解决方案比其他来源的地下水多材料因为热水比冷水更有效的溶解。当水中含有大量溶解的二氧化硅，硅华沉积在春天。石灰石，方解石的一种，是在石灰岩地区温泉特色存款。一些温泉含硫磺。除了使水的味道不好，硫发出难闻的气味。毫无疑问，臭蛋的春天，内华达州，这种情况。 11单元 一种污染物，是任何物质，生物或化学。在一个可识别的过量的有害的其他理想的生物。在这个框架内，过量的重金属如发汞；某些放射性同位素；氮，磷，钠；和其他有用的，甚至是必要的元素，以及某些致病性细菌和病毒污染物。在某些情况下，材料可作为一种污染物，世界人口中的一段特别的虽然它对其他部分不被认为是有害的。例如，在适当的复合氮超标有害于婴儿，但少了很多成年人如果在所有。在这样的方式，过多的钠盐通常不是有害的，但它可以制约医疗原因盐的摄入饮食的某些人。 不同的物理，地质，生物环境与地下水污染与地表水污染相比是显著的。在后者中，流量和氧气和阳光可用液压，随着速度的过程中污染物的稀释和扩散发生，明显不同于地下水，在污染物降解菌的机会通常局限于土壤或几英尺以下。此外，通过何种渠道地下水运动是非常小的和可变的。由此，显而易见的是，移动速度大大降低，除非，也许，在大的解决渠道内石灰石，以及分散和稀释的机会是非常有限的。此外，地下水通常缺乏氧气，这是造成好氧微生物的种类有帮助但这可能提供了一个“幸福之家”厌氧品种。 大多数土壤和岩石物理过滤出固体的能力，包括污染的固体，是公认的。然而，这种能力会随不同的大小，形状，和滤料颗粒的安排，在选定的沙子和其他材料在水过滤厂使用证明。也知道，但也许不那么普遍，是粘土和其他矿物捕获和交换的一些元素和化合物的能力时，他们游离在溶液中的正或负电荷的元素或化合物。这样的交流，随着吸附和沉淀过程中，污染物的捕获是重要的。这些过程有能力定义的单位是可逆的。他们也可以很容易地在设计设施正确的污染问题所依托的地质环境，土壤和岩石忽视治疗；这种疏忽可能造成地下水污染。这是特别重要的在污水土地应用。 很多猜测，争论，研究发生的地下水污染。地下水污染的主要关注的是化学元素，化合物的引入，和微生物，不含水层，可用于饮用水或是自然发生的，不仅因为该含水层的降解也因为在检测的难度，长期居住，和难度和费用含水层恢复。强有力的论点是，任何废物或可能的污染物应允许进入地下水系统的任何部分。这是一个不可能实现的梦想。相反，答案在于更多的了解自然过程处理废弃物的保证时，土壤和岩石是不能够处理，存储，或回收废物，我们可以发展过程使污染物处理，储存，或可回收。 Extracting and distinguishing environmental change information with high resolution form groundwater and sediments of groundwater system has been the major trend of groundwater sciences towards environmental sciences, This is very useful for forecasting environmental change.4从地下水及其沉积物中提取高分辨率的环境变化信息，实现对环境变化的预警功能是地下水科学向环境科学延伸的重要方向。5而随着全球淡水资源紧缺的形势不断恶化，全球环境变化，特别是全球气候变化对地下水资源的影响成为水文地质研究的新课题。5 With fresh water shortage increasingly serious, the research on effect of globle environmental change, especially globle climate change in groundwater resource has become a new area for hydrogeological research. 4depleted in K and SO4 井的出水量与含水层的渗透系数成正比。 Well water yield is proportional to the transmissivity of a aquifer. 1、分布在这个深层碳酸岩含水层中的地下热水的温度是60℃-90℃。 2、Temperature of the thermal groundwater in the deep-seated carbonate aquifer occurring in this area ranges from 60℃ 3、所有观测井水位的季节性波动可以用研究区降水量的季节性变化来解 4、Seasonal fluctuations in water table in observation wells are interpreted by seasonal changes of/in precipitation in study areas.