专业外语-水工部分..doc

Lesson 11 dams 坝 The first dam for which there are reliable records was built on the Nile River sometime before 4000B.C. it is used to divert the Nile and provide a site for the ancient city of Memphis. 据可靠记载，世界上第一座坝是公元前4000年以前在尼罗河上修建的。他使尼罗河改道，并为古老的孟菲斯城提供城址。 The oldest dam still in use is the Almanza Dam in Spain, which was constructed in the sixteenth century. With the passage of time, materials and methods of construction have improved, making possible the erection of such large dams as the Nurek Dam which is being constructed in the Former Soviet Union on the Vaksh River near the border of Afghanistan. This dam will be 1017 ft (333m)high,of earth and rock fill. 至今仍在使用的最古老的坝是16世纪修建的西班牙阿尔曼扎坝。随着岁月的流逝，各种建筑材料和施工方法得到了改善，修建列努克这样的大坝才成为可能。该坝正在前苏联境内靠近阿富汗边界的瓦赫什河上施工，是一座高达1017英尺（333米）的土石坝。 The failure of a dam may cause serious loss of life and property; consequently, the design and maintenance of dams are commonly under government surveillance. In the United States over 30,000 dams are under the control of state authorities. The 1972 Federal Dam Safety Act (PL 92-267)requires periodic inspections of dams by qualified experts. The failure of the Teton Dam in Idaho in June 1976 added to the concern for dam safety in the United States. 大坝失事可能造成生命财产的严重损失。因此，坝的设计和维修通常是在政府监督下进行的。美国有3万多座坝由各州政府控制着。1972年（美国）联邦大坝安全法（PL92-367）规定，必须由合格的专家对大坝进行定期检查。在1976年6月爱达荷州提堂大坝失事后，美国对大坝安全更为关切。 1 types of dams 坝的类型 Dams are classified on the basis of the type and materials of construction, as gravity, arch, buttress, and earth. The first three types are usually constructed of concrete. A gravity dam depends on its own weight for stability and is usually straight in plan although sometimes slightly curved. Arch dams transmit most of the horizontal thrust of the water behind them to the abutments by arch action and have thinner cross section than comparable gravity dams. Arch dams can be used only in narrow canyons where the walls are capable of withstanding the thrust produced by the arch action. The s