SU1137145A1 - Metho of constructing gravity dams - Google Patents

Abstract

METHOD OF CONSTRUCTION OF GRAVITATIONAL DAMS, including the zonal distribution of concrete with single-layer blocks, formwork work, laying and compaction using deep vibrators of the concrete mix, processing horizontal surfaces of construction joints before laying them following in height, including removing the cement film, and adjusting the temperature and humidity mode of each layer, characterized in that, in order to reduce the labor intensity of concrete work, the removal of the cement film from the surface of horizontal building x t seams is produced outside the part of the inner zone of the dam, where the concrete masonry nahodit- j with in a state of compression, and betonirova (inner zone A of concrete carried out with mixtures of mobility to 5 cm.. "SP

Description

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This invention relates to hydraulic construction and is intended for the construction of gravity dams.

There is a method of erecting massive concrete structures such as dams by layering the concrete mixture into blocks divided between co. a battle with embedded elements. in which the concreting of each of the layers is carried out under the conditions of an artificial climate created within the limits of the erected structure, and the height of each layer is set in accordance with the thermal engineering features of the cooling concrete system C used

The disadvantage of this method is the large labor costs for the preparation of horizontal construction joints

A known method of erecting gravity dams, including the zonal distribution of concrete, H Jie's formworking J, laying and compaction using vibratory concrete mixers, EibDc mixes, processing horizontal surfaces of building gases before they are heightwise, including removing the cement film, and adjusting temperature and humidity conditions of each layer 2. .

However, with this method of concreting, the work of removing and removing the cement film is the most labor-consuming process. With numerous horizontal construction of 1pc5, this translates into a serious disadvantage. The thickness of the removed surface layer is 2-3 mm or (with a height of single-core blocks of 0.5-i, 0 m) 0.2-1.0% of the volume of concrete laid. During the construction of large concrete dams, the loss of concrete only due to this reaches tens of thousands of cubic meters, which causes additional costs of labor, time and money for preparation, transportation and laying of concrete instead of removed from the structure.

The aim of the invention is to reduce the labor intensity of concrete work.

The goal is achieved by the fact that according to the method of erecting gravitational rafts, including zonal distribution of concrete oneA53

layer blocks, formwork work, laying and compaction using vibratory concrete vibrators, processing horizontal surfaces of construction joints before laying them on the next in height, including removing the cement film, and adjusting the temperature and humidity conditions of each layer, removing

the cement film from the surface of the horizontal construction joints is made outside the part of the inner zone of the dam where the concrete masonry is in the state of compression, and

the concreting of the inner zone is carried out with concrete mixtures with a base of up to 5 cm.

Fig. I schematically shows the proposed dam, transverse

cross section; FIG. 2 is a section A-A on.

Zonal distribution of concrete

in the dam, and the boundaries of the various technological processing of horizontal construction joints are shown in FIG. L and 2, where 1 is the outer underwater sleep, 2 is the inner zone, 3 is the outer zone from the bottom edge: and 4 is the zone of the variable water horizon. Zone B, where the cement film is removed; and Zone B, where the cement film is not removed.

The method is as follows.

in a way.

Vetonization of a gravity dam with zonal distribution of concrete is carried out by single-layer blocks with temperature control of each layer (using tents, watering, etc.). After laying the concrete mix and holding fresh concrete, the specified horizontal surface

the seam is cleaned of the cement film. However, the removal and removal of the cement film is made only from the surface of the horizontal joints located in the outer zones and in that

parts of the inner zone, where, at the design combination of loads, tensile stresses may appear (zone B in Fig. 2). Within that part of the inner zone of the dam, where

the design combinations of loads are only compressive stresses,: the cement film is not peeled off (zone B). Boundaries of that part of the inner

3

areas where the cement film is not removed from the horizontal joints are indicated in the dam project, based on the calculated stress distribution in its body (typical of stress stress in section A-A in FIG. 1).

Another prerequisite is laying in the inner zone of slow-moving and stiff concrete mixes (with mobility up to S cm / s with their compaction with powerful heavy vibrators (packages of vibrators).

Before placing the concrete mix into the next block, all the surfaces are horizontal: the surfaces of the horizontal and external construction joints and the internal zones of the Q I block with water and. blown with compressed air in the usual order.

The possibility of using the proposed method for the construction of gravity dams is due to the following.

The concrete and concrete masonry of the inner zone of gravity dams, which are protected by dense and resistant material of the outer zones, are not

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Watertightness, frost resistance or corrosion resistance are required. The compressive strength and deformative properties of the concrete masonry depend very little on whether or not the cement film is removed from the () horizontal joints. If the concrete masonry is obtained from inactive and rigid concrete

0 mixtures, in which the separation of cement milk is minimized, then there is no noticeable difference. There is also no difference in other properties of the concrete masonry, for example, bulk density.

5 As for the shear characteristics of horizontal construction joints, numerous experiments have shown that using sedentary and rigid concrete

Q mixtures with usually pro4e e QIlx for the internal zones of gravity dams, compositions of concrete with a large grain size of aggregates, the difference depends on whether or not

practical film

25 removed cement ki no.

Claims (1)

METHOD FOR ESTABLISHING GRAVITY DAMS, including zonal distribution of concrete with single-layer blocks, formwork, laying and compaction with the help of deep vibrators of concrete mix, processing of horizontal surfaces of building joints before laying the next ones in height., Including removal of cement film, and regulation of temperature the humidity regime of each layer, characterized in that, in order to reduce the complexity of concrete work, the removal of cement film from the surface of horizontal construction joints they are produced outside the part of the inner zone of the dam where the concrete masonry is in a state of compression, and the concreting of the inner zone is carried out with concrete mixtures with mobility up to. 5 cm I and