挡土墙的外文翻译.doc

Retaining wallRetaining walls are used to prevent retained material form assuming its natural slope. Wall structures are commonly used to support earth, coal, ore piles, and water. Most retaining structures are vertical or nearly so; however, if the a angle in the coulomb earth-pressure coefficient is larger than 90there is a reduction in lateral pressure that can be of substantial importance where the wall is high and a wall tilt into the backfill is acceptable .Retaining walls may be classified according to how they produce stability. mechanically reinforced earthalso sometimes called a “gravity” wall. gravityeither reinforced earth , masonry , or concrete.cantileverconcrete or sheet-pileanchoredsheet-pile and certain configurations of reinforced earth.At present, tile mechanically stabilized earth and gravity walls are probably the most usedparticular for roadwork where deep cuts or hillside road locations require retaining walls to hold the earth in place. These walls eliminate the need for using natural slopes and result in savings in both right-of-way costs and fill requirements.Cantilever walls of reinforced concrete are still fairly common in urban areas because they are less susceptible to vandalism and often do not require select backfill, typically they compete well in costs where the wall is short (20 to 50m in length) and not very high (say, under 4m). they are also widely used for basement walls and the like in buildings.The mechanically reinforced earth wall of fig.23-1 uses the principle of placing reinforcing into the backfill using devices such as metal strips and rods, geotextile strips and sheets and grids, or wire grids. There is little conceptual difference in reinforcing soil or concrete massesreinforcement carries the tension stresses developed by the applied loads for either material. Bond stresses resist rebar pullout in concrete; soil relies on friction stresses developed based on the angle of friction between soil and reinforcement or a combination of friction and passive resistance with soil and wire grids.The principle of reinforced earth is not new. Straw, bamboo rods, and similar alternative materials have long been used in technologically unsophisticated cultures to reinforce mud bricks and mud walls. Nevertheless, in spite of this long usage, French architect H. Vidal was able to obtain a patent (ca. mid-1960s) on the general configuration of fig.23-1, which he termed “reinforced earth”. We see three basic components in this figure.the earth fillusually select granular material with less than 15 percent passing theNO.200 sieve.reinforcementstrips or rods of metal, strips or sheets of geotextiles, wire grids, or chain link fencing or geogrids (grids made from plastic) fastened to the facing unit and extending into the backfill some distance. Vidal used only metal strips.facing unitnot necessary but usually used to maintain appearance and to avoid soil erosion between the reinforcements.These three components are combined to form a wall whose side view is shown in fig.23-2. When wire mesh or other reinforcement with discontinuities (grid voids) is used, apportion may be bent , similar to the sheet of fig.23-3, to form a facing unit. Grid-type reinforcements strengthen the soil through a combination of friction and passive pressure pullout resistance. The bent-up portion used as a facing piece provides some erosion control until the wall is completed.The exposed reinforcements are usually sprayed with concrete mortar or gunite ( matrial similar to mortar) in lifts to produce a thickness on the order of 150 to 200 mm. this is both improve the appearance and to control erosion. For metals this covering also helps control rust, and for geotextiles it provides protection from the ultraviolet rays in sunlight and discourages vandalism. The basic principle of reinforced earth is shown in fig.23-4 where we see a wall acted on by either the Rankine or coulomb active earth wedge. Full-scale tests have verified by reinforcing strip tension. Strip tension is developed in the zone outside the active earth wedge from the friction angle between strip and soil and the vertical earth pressure on the strip. With no lateral earth pressure left to be carried by the wall facings, they can be quite thin and flexible with the principal functions of ersion control and appearance.挡土墙是用来防止保留的物质形式，假设其自然坡度。墙结构通常是用来支持土体，煤炭，矿石堆，和水。大多数挡土墙是垂直的或接近竖直的，然而，但库伦土压力系数中的角大于90度时，侧压力将减少，这对于高度高的挡土墙以及回填区倾斜的挡土墙具有重要意义根据挡土墙如何产生的稳定性可分为。机械加筋土有时也被称为“重心”的墙上。重力无论是加筋土，砖石或混凝土。悬臂混凝土或钢板桩锚板桩与加筋土的某些配置。目前，加筋挡土墙和重力式挡土墙广泛应用，尤其是在深挖和山坡位置的道路工程中需要利用挡土墙来保护土体稳定的情况下。钢筋混凝土悬臂墙仍相当普遍在城市地区，因为他们是不容易受到破坏，往往不需要选择回填，通常他们在成本竞争的墙很短（20米长）并不是很高（比如说，下）。他们还广泛用于地下室墙和建筑物等。图23-1采用机械加筋土挡土墙的原则，回填使用的设备，如金属条和棒，土工布条，床单和网格，或线网将加强。很少有概念上的差别加固土或混凝土加固群众进行紧张压力所开发的应用负载或材料。钢筋混凝土的粘结力抗拔；土壤依靠摩擦应力的基础上制定的摩擦角土壤加固或组合的摩擦和被动阻力与土壤和网格线。加筋土的原理早已出现，并非什么新技术，早期时代人们长期采用稻草、竹竿以及类似的材料来加强泥砖和泥墙。然而，尽管这长期的使用中，法国建筑师H.维达尔能够获得的专利（约20世纪60年代中期）的一般配置图23-1，这是他被称为“加筋土”。在此图中，我们看到了三个基本组成部分。填土通常会选择小于15通过200号筛的颗粒材料。加固条或杆，土工布，线栅，或链链接围栏或格栅（由塑料制成的网格）紧固到面对单元和伸入回填一段距离的金属，带材或片材。维达尔只用金属条。防护面不是必要的，但通常用来保持外观和防止水土流失的。这三个组件组合起来形成一个墙的侧视图显示在fig.23-2。当网或其他加固与不连续（网格空隙）是用来分摊，可弯曲，类似于fig.23-3表，形成一个单位。网格式钢筋加强土