Water heating of concrete when grouting section joints of the Sayano-Shushenskoe dam

Abstract

To simplify works on restoration of the roller tracks of the main fixed-axle gates of the culverts when they are worn and to reduce expenditures, the design of the roller tracks was fundamentally changed, Instead of the embedded cast tracks, rolled plates in which removab%e forged bushings are fastened are used (Fig. 4), The operation of repair of the roller tracks amounts to replacing the worn bushings with new ones A fundamentally new scheme of automatic control of locking based on the use of noncontact logic elements was developed for the first time in the design of the Cheboksary lock. The main component in this scheme is a logic machine controlling locking, which has a number of substantial advantages compared to the relay scheme:high degree of reliability providing continuous 24-h operation during the navigation season; the logic elements composing the machine have a practically unlimited service life (guaranteed life, 12 years); high noise stability; simplicity of maintenance; low cost.The logic machine controlling locking performs the following operations: a) reception of information arriving from the dispatcher's control board and formation of a system of instructions controlling the operation of the actuating mechanisms in conformity with algorithm for the technological process of locking; b) reception and storage of information arriving from external sensors monitoring the operation of the actuating mechanism of the lock (degree of filling of the lock chambers, position of the gates, etc.); c) control and monitoring of the operation of the light signals; d) protection of the mechanisms and devices of the lock from accidents and prevention of emergency situations.The introduction of the aforementioned designs aimed at increasing the reliability and improving the operating conditions of the lock effect also a considerable saving. The plan of construction work calls for a stepped scheme of constructing the SayanoShushenskoe dam with offsetting of the downstream face with differences of heights between columns as much as 35-55 m. Construction of the dam is accompanied by filling of the reservoirs which necessitates its annual stage-by-stage sealing by grouting the joints between the columns and sections.A grouting temperature of +2-7~ is achieved by pipe cooling of the concrete.The spacing of the pipe coils is 1.5 x 1.5 m.The bulk of the works on sealing the dam, with consideration of its state of stress, should be performed in the winter--spring period during seasonal drawdown of the reservoir. Grouting works at a concrete temperature below 0~ are not permitted by the existing technological regulations.However, the design characteristics of the dam and scheme of its construction and the climatic conditions of the construction region do not make it possible to completely eliminate freezing of the concrete,The vertical and horizontal surfaces are exposed to the effect of outside air temperature for a long time, in some cases up to 2-3 years.This leads to the penetration of the frozen zone of concrete to a d...