外文翻譯----克拉斯諾亞爾斯克水電站大壩大體積混凝土溫度控制

1、附錄：英文原文TEMPERATURE CONTROL OF THE MASSIVE CONCRETEOF THE KRASNOYARSK HYDROELECTRIC STATION DAMA. P. Dolrnatov and S. Z. Neidlin UDC 627.821.2 : 666.972.021.21.035.83(282.251.2)During recent years a number of large

2、 hydroschemes with high massive concrete dams have been bnilt in areas of the USSRin an area of extreme climate. A number of problems arise in the erection of massive dams under severe climatic conditions related to the

3、prevention of fissuring in the concrete and obtaining a monolithic structure.Typical features of the construction of large hydroschemes are the large volumes of concrete and the extremely limited time for pouring them, w

4、hich means a high rate of concrete placing.Measures for controlling the temperature of the concrete on a large scale were adopted practically for the first time in the Soviet Union in the construction of the Krasnoyarsk

5、hydrocomplex. The severe climatic conditions at the site (mean annual temperature +0.4 , maximum long range temperature +37and minimum, -54 ) introduced serious difficulties in obtaining monolithic mass structures and pt

6、aced special demands on the concrete and its placement. In order to obtain monolithic concrete structures,the “Technical regulations for carrying out concreting“ lays down the following temperature conditions for blocks

7、with columnar section (plan dimensions 15 x 11.5 m, height 3 to 9 m):a) maximum temperature in blocks placed on fresh concrete (less than 1 month old) must not exceed 40 ;b) maximum temperature in blocks placed on old co

8、ncrete (more than i month old) and rock must not exceed 28 ;c) the temperature drop between the core and faces must not exceed 23 ;The numerator shows the amount of concrete placed or cooled during the year; the denomina

9、tor shows the volume and increase in the amount.200,000 m S of this concrete was cooled using water cooled in a refrigeration plant.Concrete placing in the top section of the dam, which is intended for completion by 1969

10、-1970, will be carried out without artificial cooling.Cooling of the concrete during the construction of the Krasnoyarsk hydroelectric station was carried out in two stages. In the first stage cooling was used for reduci

11、ng the exothermic peak of the freshly placed concrete and in the second stage for further cooling of the mass down to the temperature where it is made monolithic.First stage cooling was carried out usually in the summer

12、only but from 1965, with the introduction of high blocks, it was carried out in winter. From 1966 the first stage cooling was carried out continuously for the purpose of improving the concrete stress in the immediate vic

13、inity of the cooling pipes, accelerating cooling of the block, for rendering the joints between columns monolithic and improving reliable performance of the cooling coils (leaching).The second stage usually starts at the

14、 end of August with a water temperature of 15-18 . During this period the concrete is cooled mainly from a temperature above 25-30 , for the purpose of further reducing the temperature towards the winter season and in pr