土木工程专业英语LESSON16.ppt

16 Foundations基础 1.New words analysisDescription(n.描述描述)describe (描写描写)形似词：形似词：prescription（n.处方）处方）prescribe（V.开处方）开处方）Cautionprecaution(预防措施预防措施)Enlarge=en(v.前缀或后缀，使前缀或后缀，使)+large，strengthen=strength+en,widen=wide+enRetention(n.保留保留)retain（v.保留）保留）+tionDiscontinuity=dis+continuitySubside(下陷下陷)=sub（下、次）（下、次）+sideInfiltrate(渗入渗入)=in+filtrate(v.滤滤)Encase=en en(v.前缀或后缀，使前缀或后缀，使)+case(容器容器)Weep(滴水、渗漏滴水、渗漏)weep(哭泣哭泣)Flexibility(n.弹性、柔性弹性、柔性)flexible（adj.柔性的）柔性的）Backfill(回填回填)fill backAdmixture=ad(前缀前缀，to的意思，往的意思，往)+mixtureMultistory(多层的多层的)=multi(前缀：多前缀：多)+storyCode=specification 标准、规范标准、规范Cutoff wall=止水墙止水墙2.长句、难句分析长句、难句分析Exam.1 the sizes of footings are determined by dividing the loads to be imposed at the base of the footing by the allowable bearing pressure which can be imposed on the soil or rock of the earth.分析分析 这里的两个这里的两个by是造成翻译困难的主要原因。第一个是造成翻译困难的主要原因。第一个by与与determine搭搭配，第二个配，第二个by与与divide搭配（搭配（divided by）。搞清了这个关系，翻译不难。）。搞清了这个关系，翻译不难。参考翻译参考翻译 基础的大小由上部结构传至基础底部的荷载除以承受该荷载的土基础的大小由上部结构传至基础底部的荷载除以承受该荷载的土或岩石的容许应力来决定。或岩石的容许应力来决定。Exam.2 Mat or raft foundations are large,thick,and usually heavily reinforced concrete mats which transfer loads from a number of columns or columns and walls to the underlying soil or rock.分析分析 此处翻译的争议点在于对此处翻译的争议点在于对heavily reinforced 的处理。有人翻译为：的处理。有人翻译为：重量大。本人认为：重量大。本人认为：reinforced是配筋的意思，是配筋的意思，heavily reinforced 是指配是指配筋很重，即配筋量大。虽然，其结果肯定会引起重量加大，但翻译成配筋量筋很重，即配筋量大。虽然，其结果肯定会引起重量加大，但翻译成配筋量大更准确、更容易学生理解。大更准确、更容易学生理解。参考译文参考译文1：板式基础或筏式基础通常是一些面积、厚度及配筋量都很大的钢：板式基础或筏式基础通常是一些面积、厚度及配筋量都很大的钢筋混凝土板块，其作用是将柱子或柱子和墙上的荷载传到下卧土层或岩层中。筋混凝土板块，其作用是将柱子或柱子和墙上的荷载传到下卧土层或岩层中。参考译文参考译文2：板式基础或筏式基础通常指把柱子或柱子和墙上的荷载传到下卧：板式基础或筏式基础通常指把柱子或柱子和墙上的荷载传到下卧土层或岩层中的面积、厚度及配筋量都很大的钢筋混凝土板块。土层或岩层中的面积、厚度及配筋量都很大的钢筋混凝土板块。Structures or other constructed works are supported on the earth by foundations.建筑物或其它的构造物是由土地上的基础支撑的。The word foundation may mean the earth itself,something placed in or on the earth to provide support,or a combination of the earth and the elements placed on it.“foundation”这个单词或者是指土地本身，或者是指插入在土地上以提供支撑的物体，或者是指土地和立于其上的物体的合称。The foundation for a multistory office building could be a combination of concrete footings and the soil or rock on which the footings are supported.对于一栋多层办公楼，“foundation”可能是混凝土基础和支撑基础的土或岩石的合称。The foundation for an earth-fill dam would be the natural soil or rock on which the dam is placed.对于一个挡土坝，“foundation”可能指的是为大坝提供支持力的天然土地或岩石。Concrete footings or piles and pile caps are often referred to as foundations without including the soil or rock on which or in which they are placed.混 凝 土 基 础 或 桩 基 或 桩 承 台 通 常 指 的 就 是“foundation”，不包括为基础提供支持力的土体或岩石。The installed elements and the natural soil or rock of the earth form a foundation system;the soil and rock provide the ultimate support of the system.已就位的基础和天然土体或岩石形成了一个基础系统，土体和岩石提供了系统的最终支持力。Foundations that are installed may be either soil-bearing or rock-bearing.已就位的基础或者是由土地支撑或者是由岩石支撑。The reactions of the soil or rock to the imposed loads generally determined how well the foundation system functions.施加的荷载时，土体或岩石的反应决定了基础系统功能的好坏。In designing the installed portions,the designer must determine the safe pressure which can be used on the soil or rock and the amount of total settlement and differential settlement which the structure can withstand.在选择就位点时，设计者必须决定安全压力，即作用在土体或岩石上并且结构能承受的整体建筑物和不同建筑物作用的荷载量。The installed parts of the foundation system may be footings,mat foundations,slab foundations,and caissons or piles,all of which are used to transfer load from a superstructure into the earth.基础系统已安装部分也许是独立基础，片筏基础，平板基础，箱型基础或者是桩基。These parts which transmit load from the superstructure to the earth,are called the substructure(Fig.1).它们都是将荷载从上部结构传入到地下。这些将荷载从上部结构传到地下的部分叫做下部结构。（图1）Footings.Footings or spread foundations are used to spread the loads from columns or walls to the underlying soil or rock.基基础础。独立基础或扩展基础被用作将来自柱或墙的荷载扩散到下面的土体或岩石。Normally,footings are constructed of reinforced concrete.However,under some circumstances they may be constructed of plain concrete or masonry.一般说来，基础由钢筋混凝土构成。然而，在一些情况下，它们也许由素混凝土或者砂浆构成。When each footing supports only one column,it is square.当一个基础只支撑一个柱的时候，它是方形的。Footings supporting two columns are called combined footings and may be either rectangular or trapezoidal.支撑两个柱的基础被称作联合基础，它们也许是梯形也许是长方形。Cantilever footings are used to carry loads from two columns,with one column and one end of the footing placed against a building line or exterior wall.悬臂基础被用来传递两个柱的荷载，支持一个柱和另一个位于与建筑物线或者是外墙线相对应的基础尾端上的柱。Footings supporting walls are continuous footings(Fig.2).撑墙的基础叫做连续基础。（图2）The sizes of footing are determined by dividing the loads to be imposed at the base of the footing by the allowable bearing pressure which can be imposed on the soil or rock of the earth.基础的尺寸是由可能施加在基础底部的荷载除以地基土和岩石能够承担的容许承载力来确定的。Most building codes and textbooks on foundation contain tables listing allowable bearing pressure for various types of soil and rock;however,these tables give only general classifications and descriptions of the soil or rock and must be used with caution.大部分建筑规范和教科书关于基础部分都包括不同类型土体或岩石的容许支撑力图表。然而，这些图表仅仅给了一个对土体或岩石粗略分类的描述。因此，使用时必须小心。More specific information about the soil or rock is normally obtained by drilling test boring,extracting soil or rock samples,performing laboratory tests on the sample,and making engineering analysis to determine suitable bearing pressures.更多关于土体或岩石的具体信息要靠钻探试验：选择土体或岩石试样，室内试验和决定容许承载力的工程分析获得。in addition to bearing pressure,consideration must be given to the amount of settlement which may occur and the capability of the structure to withstand such settlement.除承载力外，结构的沉降量也要控制。if settlement is a problem it may be necessary to use an alternate foundation type rather than footing or to enlarge the footing and decrease the bearing pressure.如果沉降是一个问题，那么也许有必要用一个可替换的基础形式，而不是独立基础，或者增大基础尺寸以减小压力。Fig.2.Types of footings.(a)Column footing.(b)Combined footing,which can be either rectangular or trapezoidal.(c)Cantilevered footing.(d)Wall footing.elevation n.上升,举起,晋级,提升;上进,向上,提高,增加,崇高,壮严高地,高程,高度,海拔仰角,射角;【测】标高【建】正视图;立视图Grade beams may be used between exterior column footings to support walls，with the beams transferring the weight of the walls to the column footings.基础梁用在外部柱基础之间以便支撑墙，基础梁传递墙重到柱基础。Beams are also used between interior column footings to act as braces or ties or to support interior walls.梁也用在内部基础之间用作支撑或节点或支撑内部墙体。Retaining walls are those walls subject to horizontal earth pressures due to the retention of earth behind them.挡土墙是那些因墙后有土而承受水平土压力的墙。The foundations for these walls must have sufficient frictional resistance with the soil or rock on which they rest so that they will not slide when subjected to the horizontal earth pressure.这些墙的基础必须和为其支撑的土体或岩石之间有足够的摩擦阻力，以便当它们受到水平土压力的时候不会滑移。In addition,retaining walls must be designed so they will not overturn.In frost-susceptible areas,footings must be placed below the frost line.另外，挡土墙必须设计成这样才不会倾覆，在冰冻敏感地区，基础必须置于冰冻线下。Mat foundations.Mat or raft foundations are large,thick,and usually heavily reinforced concrete mats which transfer loads from a number of columns or columns and walls to the underlying soil or rock.筏筏式式基基础础。板式基础或者浮筏基础通常是把荷载从柱子或者柱和墙传到地基土或岩石的面积，厚度，重量都很大的钢筋混凝土底板。Mats are also combined footings,but are much larger than a footing supporting two columns。筏板也是联合基础，但比支撑两个柱的基础大得多。they are continuous footings and are designed to transfer a relatively uniform pressure to the underlying soil or rock.它们是连续基础，并且设计成传递相对均匀的压力到下面的土地或岩石。Mats are rigid and will act as a bridge over discontinuities in the soil or rock on which they are founded.筏板是刚性的并且像一架桥立在不连续的土地或岩石上。Mats founded several meters below the ground surface,when combined with external walls,are termed floating foundations.平板建造在地面以下几米深处，当与外墙结合时就是所谓的浮筏基础。The weight of the soil excavated from the ground surface to the bottom of the mat may be equal to or approach the total weight of the structure.从地表到平板底部所挖掘的土体重量也许等于或接近于整个结构的重量。In this case,little or no new load is applied to the underlying supporting soil,and settlements of a structure may be minimal after construction.这种情况下，极少或者是没有荷载作用在地基土上，结构的荷载也许在建造后沉降降低到最小。Slab foundations.Slab foundations are used for light structures wherein the columns and walls are supported directly on the floor slab.The floor slab is thickened and more heavily reinforced at the places where the column and wall loads are imposed.平平板板基基础础。平板基础并用在轻结构上，在这里，柱子和墙直接支撑在底板上，底板被加厚了，而且在柱子和墙荷载作用的地方厚度加强了。Special problems。Groundwater is a major problem in connection with the design and installation of foundations where a substructure is to be placed below the groundwater level.特殊问题特殊问题。下部结构置于地下水位线以下时，地下水是一个与基础设计安装相联系的重要问题。Well points,pumping from deep wells,or pumping from sumps are methods used to dewater construction sites during foundation installation.dewater脱水,去水,浓缩;排水,疏水;降低水位从深井中抽水或从集水井中抽水是在基础施工期间用于施工现场排水的方法。Other methods which are less often used are freezing of the water in the soil,removal of water by electro osmosis,and the installation of cutoff walls made of pilling or grout around the periphery from within the excavation.periphery周围;圆周;边缘;周界其它不常用的方法有：冰冻土中水，电渗排水和安装由开挖周围灌浆形成的止水帷幕。If dewatering operations are performed in an area surrounded by existing structures,precautions must be taken to protect them,as the lowering of the groundwater may cause the soil on which they are supported to subside.如果排水作业在有现存建筑物包围的场地进行，就必须采取预防措施来保护这些建筑物，因为降低地下水有可能引起支撑这些建筑物的土下沉。If a basement is partially or totally below the groundwater level its walls must be designed to withstand the hydrostatic pressures of the water on the outside in addition to the pressure from the soil backfill.如果地下室部分或者完全位于地下水位线以下，那么它的墙除了设计成承受墙后土压力还要承受外面的静水压力。An alternate procedure is to install a permanent system to remove water outside the walls.一个替代方法就是安装一个渗透系统把水移到墙外。Some substructures below groundwater level may at times be subjected to hydrostatic uplift forces which are greater than the downward forces imposed by the structures.In these cases,provisions must be made to anchor the structures to prevent them from floating upward.一些位于地下水位以下的地下结构，可能由此受到向上的静水压力，此力超过了结构施加的向下的力。在这种情况下必须有锚固结构以阻止它们向上漂浮。Groundwater also causes problems by infiltrating through basement walls,slabs,and joints into the basement itself.地下水也造成了这样的问题：渗透地下墙，板，节点到地下室内。This can be prevented or reduced by providing an external permanent drainage system that carries water away from the basement,by encasing the walls and slabs in an impermeable plastic membrane,or by coating the external walls with an asphaltic mastic to lower their permeability.impermeable plastic membrane不透性膜 提供一个外部永久的排水系统把水排出地下室或把墙或板放在一个不可透过的塑料膜里，或者是给外墙涂一层沥青乳香以降低渗透力，这样可以减少地下水的渗透。Combinations of the foregoing are also used.前面所描述的方法结合起来也用过。Retaining walls and abutments often have weep holes in the lower sections through which water accumulating behind the walls or abutments can escape.挡土墙和桥墩通常在低段处有集水孔，通过集水孔，聚集在墙或桥墩后面的水就可以排出。The water pressure behind the walls is relieved as the water flows through the walls into an open external drainage system.当水通过墙流进敞开的外部排水系统时，墙后的水压力就会减少。Foundations placed on expansive soils are often subjected to distressing movements unless special precautions are taken.基础置于膨胀土体上时也通常遭到令人头疼的位移，除非采取专门的预防措施。Expansive soils are those which swell and contract excessively with varying amounts of moisture.膨胀土是那些在不同量的湿气下过分膨胀或收缩的土。Problems can be overcome by installing foundations below the zone of significant change in moisture content and backfilling with nonexpansive materials,by altering the soil with an admixture such as lime or cement so that volume changes do not occur,or by providing flexibility in the structure to accommodate movements.问题可以这样解决：基础安装在湿气条件有重大变化的区域里；回填非膨胀材料；土中添加石灰或水泥掺合剂以便体积不发生改变；使结构变得柔韧以适应位移。Underpinning of foundations is often necessary,and it may either remedial or precautionary.Underpinning基础；支承结构补救型或者是预防型的地基支撑通常是有必要的。Remedial underpinning is used to correct defects in existing foundations which may have settled excessively.补救型地基支撑用在纠正基础定位超出时存在的偏差。If the structure is to be saved or returned to its original state,additional foundation support must be provided.如果被恢复到原始状态，则必须提供额外的基础支撑Precautionary underpinning is used when new structures are to be installed adjacent to or beneath existing structures,as in the construction of city subways.预防型地基加固用在当新结构安装在靠近或位于这样的结构物下面，如城市地铁结构。Underpinning of foundations is a specialized construction technique,The work is generally performed in a confined space,such as the basement of a building,or in small pits excavated outside a building area.基础支撑是一门专业的建造技术。工作通常在一个限定的地方进行，如一栋建筑物的地下室或一栋建筑物外面开挖的基坑里。It is necessary to provide support for the loads of the existing structure while new foundations are installed.当新基础安装时必须对存在的结构荷载提供支撑。The new foundations may be footings which are placed deeper in the ground than the original foundations,or they may be piles or caissons.新基础或者是定位比最初的基础深的基础或者是桩基或是箱型基础。Underpinning of a wall footing may be performed by excavating pits adjacent to and beneath existing foundations.The pits are small,some 3 ft(0.9m）wide by 4 ft(1.2)long.墙基支撑靠在已存基础附近或下面挖坑来实现。坑较小，一般0.9米宽，1.2米长。Horizontal sheeting is placed in the pits as excavation proceeds to prevent caving of the walls and undermining of the structure being underpinned.随着开挖的进行，水平板被置于基坑上，以阻止墙下沉和被支撑结构的破坏。When the new bearing stratum is reached,forms are placed in the pit,and concrete is poured from the new bearing stratum up to within3-in.(76-mm)of the bottom of the old footing.当到达新的承压层时模板被安置在基坑里，从新的承压层向旧的基础底部浇灌76毫米厚的混凝土。After the new concrete has hardened,the3-in.(76-mm)space is packed by hand with a mixture of sand,cement,and a small amount of water.在新浇得混凝土硬化后靠砂，水泥和少量水的混合物压紧76毫米的混凝土。Called grout,the mixture is packed very tightly into the space between the top of the new footing and the underside of the old footing.所谓得泥浆，即混合物被压实紧密，送到新基础顶部和旧基础下部之间。The pit underpinning process is repeated throughout the entire length of the wall footing.The resulting new foundation may be a continuous wall or intermittent piers.在整个墙基长度范围内基础支撑过程重复进行。结果，新基础也许是连续墙也许是间断的桥墩。