JPS585347B2 - Cooling method for poured concrete during construction of large concrete structures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cooling poured concrete in the construction of large concrete structures such as dams.

Generally, when constructing a large concrete structure such as a dam, it is difficult to continuously pour a large amount of concrete over the entire structure, so as shown in Fig. Block B...
Furthermore, in each block B..., concrete is poured step by step at a certain height to form multiple upper and lower stages U.
The method of construction is to pile up...

In this case, the concrete tends to temporarily rise in temperature due to heat of hydration, etc., and such temperature rise causes irregular cracks to occur due to shrinkage due to subsequent cooling.

Therefore, it is necessary to cool the concrete in order to suppress the cracking by reducing the temperature difference between the maximum temperature rise and the final stable temperature as much as possible.

Particularly in the case of large dams, it is required to install cooling piping at each stage of concrete pouring, and to cool the concrete by supplying cooling water from the outside to the piping for a certain period of time during and after pouring. ing.

In this case, the cooling piping needs to be embedded in the concrete in such a way that it can be connected to an external cooling water supply means both during and after concrete pouring. The pipe is formed with a thin wall, so
There are special circumstances in which the end of the pipe cannot be threaded for direct connection.

Conventionally, a method shown in FIG. 2 has been used as a cooling means in such a case.

That is, in this method, a trapezoidal wooden frame 5 is attached to the inner surface of a template 2 placed on the outside of the stage Un in which concrete 1 is to be poured, and a trapezoidal wooden frame 5 is attached to the wooden frame 5 with an abbreviation called a gooseneck. One end of the S-shaped joint pipe 4 is inserted and the gooseneck 4 is raised to the concrete placement location of the next stage Un+1, while the cooling pipe 3 installed in the relevant stage Un is raised in advance from the previous stage Un-1. (See Figure 2a).

Next, by pouring concrete 1 in this step Un, and then removing the template 2 and wooden frame 5, a gooseneck 4 is placed in the recess 6 after removing the wooden frame 5 on the outer surface of the concrete 1 in the step Un. One end is exposed, and the other end of the gooseneck 4 is made to protrude from the upper surface of the concrete 1 to the next stage Un+1, making it possible to connect to the cooling pipe arranged in the next stage Un+1 (see Figure 2).

In addition, when casting the stage Un, the ends of the goosenecks 4 exposed in the recesses 6 at the front and rear Un-1 in advance are connected to the supply ports 8 of the cooling water supply pipes 7 installed outside of the goosenecks 4 with hoses 9, etc. Supply cooling water by connecting through.

This process is repeated for each stage.

In short, this method involves supplying cooling water through the gooseneck 4 installed in advance in the previous stage, since the stage is surrounded by the template 2 during pouring.

However, in this method, when pouring, the concrete 1 is poured around the gooseneck 4 for cooling the next stage, which has ends and stands up in an S-shape in an unstable and fragile state. The gooseneck 4 is easily deformed, damaged, and detached from the wooden frame 5 due to the force applied from 1, and to prevent this, great care must be taken during the pouring work, which is a serious drawback in that work efficiency is significantly reduced. was there.

In view of these circumstances, the present invention is designed to improve the concrete casting work for each stage of concrete that is poured in multiple stages above and below.
It eliminates the need for preliminary gooseneck installation work for the next stage cooling sump, and connects the cooling piping and external cooling means directly to each stage to enable cooling during and after pouring. It is an object of this invention to provide a method for cooling concrete in the construction of large concrete structures, which eliminates the conventional problems such as deformation and damage of goosenecks, and greatly simplifies the work of concrete pouring and cooling sump. It is something.

Embodiments of the present invention will be described below with reference to the drawings.

In the illustrated example, a dam is illustrated as a large concrete structure, and as mentioned above, the construction method is to construct a dam of an appropriate size (for example, 15 to 20 meters square) from the top view of the dam.
Block B1. Each block is divided into blocks B2 and concrete 11 is placed at a certain height, for example, from 1 to 1.
The concrete is poured stepwise in multiple steps U...5m).

In this construction, cooling equipment is provided for each stage U as shown in FIGS. 3 to 6, and the method of the present invention is carried out.

In these figures, 12 is a template, 13 is a cooling pipe provided for each stage of each block, and 20 is a connector.

In addition, 16 is a cooling water supply pipe, which is normally installed on one side of the block B1 on the downstream side of the dam, and can be extended in units of length as concrete is layered one by one. Connected to a water source (not shown) via a pump.

To explain the specific method according to these diagrams, for example, the stage Un
The cooling piping 13 is installed in the.

This piping 13 itself is the same as the conventional one, and is formed into a meandering shape or the like so as to cover almost the entire concrete placement space as shown in FIG. They are arranged close to each other downstream on one side.

Note that similar piping 13 is installed in other blocks when concrete is poured, but the piping 13 of block B2 on the upstream side or in the middle is connected to the piping 1 by an appropriate connecting fitting 15.
It is led out to the vicinity of the downstream end of the block B1 via a linear auxiliary pipe 14 connected to the block B1.

Therefore, in addition to the cooling pipe 13, the auxiliary pipe 14 is provided in the block B1 as required.

On the other hand, in the stage Un, a template 12 is arranged around the concrete casting range, and the template 12 on the downstream side
In this case, the connectors 20 are removably attached in a penetrating manner at positions corresponding to each end of the cooling pipe 13.

The template 12 is made of a metal plate, and mounting holes 12a are drilled in advance, and the connectors 20 are fitted and fixed into the respective mounting holes 12a.

Then, as shown in FIG. 4, the connectors 20 are connected to each end of the cooling pipe 13 inside the template 12.

The connector 20 includes a connection part to the cooling pipe and a connection part to the cooling water supply means, and connects the cooling pipe 13 and the cooling water supply pipe 16 via a hose or the like when attached to the template 12. It is configured such that the parts can be connected in communication with each other, and a part that can be connected to the hose etc. is left even after the template 12 is removed.

For example, as shown in FIG. 7, the connector 20 includes an end member 21 for connection to a cooling pipe, a cap-shaped frame 25 that is screwed into the member 21, and a cylindrical shape that is screwed into the frame 25. member 33;
A tightening nut 36 is provided facing the cap-shaped frame 25 and screwed into a cylindrical member 33, and each of these members is molded from malleable cast iron, aluminum die-casting, high-strength plastic, or the like.

The terminal member 21 is formed into a nut shape with a screw 22 carved on the inner circumferential surface, and has a protrusion 23 connected to the inner circumference of one end, and an annular rubber packing 24 for fixing the pipe is inserted inside. .

The cap-shaped frame body 25 has a male threaded cylinder part 27 protruding from the small-diameter end of a cap-shaped outer frame part 26 to be screwed into the terminal member 21, and a nut-shaped part 28 is provided inside the outer frame part 26. A nut-shaped part operation space 29, which opens toward the larger diameter side of the outer frame part 26, is formed between the inner surface of the outer frame part 26 and the nut-shaped part 2B.

30 is a rubber gasket installed inside the nut-shaped portion 28;
Reference numerals 1 and 32 denote rubber gaskets attached to the end surfaces of the outer frame portion 26 and the nut-shaped portion 28 to improve adhesion to the template 12.

Further, the cylindrical member 33 has a cap-shaped frame 2 on its outer peripheral surface on one end side.
5 and a screw 34 to be screwed into a tightening nut 36, and the other end has a screw 35 carved on the tapered outer circumferential surface for connection to a hose or the like.

Note that 37 is a cap that protects the end of the cylindrical member 33, and is removed when connecting a hose or the like to the cylindrical member 33.

Therefore, when using this connector 20, the cylindrical member 33
One end is inserted into the mounting hole 12a of the template 12, and the cap-shaped frame 25 is screwed onto one end of the cylindrical member 33 on the inner surface of the template 12. By tightening the nut 36 screwed onto the shaped member 33, these are attached to the template 20 in a clamping manner.

Further, the end member 21 is screwed into the externally threaded cylindrical portion 27 protruding from the cylindrical frame 33, and the cooling piping 13 is attached to the end member 21.
By inserting the
The packing 24 is elastically deformed and crimped onto the end of the pipe from the periphery.

By doing so, it is possible to securely fasten a cooling pipe which is too thin to be threaded.

In this way, each end of the cooling piping 13 is connected to the connector 20 attached to the template 12, respectively.

In addition, when the auxiliary piping 14 as described above is installed, the above-mentioned connector 20 or a similar metal fitting is attached to the template 12, and the auxiliary piping 14 is attached to this metal fitting.
Connect the ends.

Next, in this state, concrete 11 is poured into the relevant step Un.

At this time, in the present invention, the connecting fitting 20 attached to the template 12 forms a lead-out portion for connecting the cooling pipe 13 on the same level as the connecting fitting 20 to an external cooling water supply means.

For this reason, there is no need to perform concrete pouring work in an unstable state where the gooznet, which is the lead-out part of the next-stage cooling piping, is stood up independently, as was the case in the past.
0 and the cooling pipe 13 are linearly connected, the robustness during casting is maintained and the casting work becomes much easier.

During concrete pouring, as shown in FIGS. 5 and 8, one end of the hose 17 is connected to the supply port 16a of the cooling water supply pipe 16, and an existing attachment provided at the other end of the hose 17 is connected. The metal fitting 17a is connected to the cylindrical member 33 of the connecting tool 20.
By screwingly connecting the connector 20 to the cooling water supply pipe 16 via the hose 17, cooling water is supplied into the cooling pipe 13.

In addition, after concrete pouring, a certain amount of concrete 11
The template 12 is removed when it becomes solid, but at this time,
In the connecting tool 20 shown in the embodiment, the nut 36 is loosened, the cylindrical member 33 is rotated to separate from the template 12 and the cap-shaped frame 25, and then the template 12 is removed.

Furthermore, the cap-shaped frame 25 is removed by rotating it using its nut-shaped portion 28.

Thus, the end member 21 is attached to the end of the cooling pipe 13.
This will face outward from the truncated conical recess 40 formed on the outer surface of the concrete 11.

After the template 20 is removed, the terminal member 20 can be connected to the terminal member 20 by using, for example, a cylindrical auxiliary metal fitting 41 having a connecting portion to the terminal member 21 and a connecting portion to the accessory fitting 17a of the hose 17.
1 and a hose 17, cooling water is supplied to the cooling pipe 13 for an appropriate period.

Note that the removed connector 20 can be used together with the template 12 for the next stage of concrete pouring work by replenishing the terminal member 21.

In this way, each stage U is equipped with a cooling facility, and cooling water is supplied to the cooling piping 13 in the concrete 11 during and for a certain period of time after concrete pouring.

Furthermore, by connecting the auxiliary piping 14 to the cooling piping 13 of the corresponding stage of the other block B2 during concrete pouring, cooling water is also supplied to the other block B2 through the auxiliary piping 14.

After the cooling period has passed, the cooling pipe 13 and the auxiliary pipe 14 are filled with cement milk.

The present invention is applicable not only to the construction of dams, but also to the construction of various large concrete structures, such as piers of human-shaped bridges, in which concrete is poured step by step at a constant height. It is used for cooling.

As shown above, the method for cooling poured concrete of the present invention involves cooling piping installed in the stage that replaces the concrete being poured, and templates when pouring concrete in multiple stages above and below each stage. The cooling water can be injected by connecting the cooling water injectable connector, which is removably installed through the concrete, and the concrete is poured in this state, so cooling during and after pouring is possible. While making it possible to supply water, there is no need to carry out pouring work in an unstable state where the Guznetsuk is stood up alone as in the past, and the robustness of the piping system is increased during concrete pouring, preventing damage and deformation. In addition, the concrete placement work becomes easier and work efficiency can be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a dam, Fig. 2a and the same are partial cross-sectional views showing a conventional cooling method for poured concrete, and Figs. Figure 3 is a partial plan view showing the state of cooling piping installation, Figure 4 is a partial cross-sectional view of the connectors connected to the cooling piping and attached to the template, and Figure 5 is a partial plan view showing the state of cooling piping installed. FIG. 6 is a partial sectional view showing the state of water supply; FIG. 6 is a partial sectional view showing the state of cooling water supply after removing the template; FIG. 7 is an enlarged perspective view of the connector used in the present invention in an exploded state; FIG. FIG. 9 is an enlarged sectional view of the connecting tool in the attached state, and FIG. 9 is an enlarged sectional view of the main part after the template is removed. 11... Concrete, 12... Template, 13... Cooling piping, 16... Cooling water supply pipe, 20... Connection tool.

Claims (1)

[Claims] 1. In construction work where large concrete structures such as dams are built by stacking concrete in multiple stages above and below by repeating the work of placing concrete step by step at a constant height, concrete is poured during and for a certain period of time after the concrete is placed. This is a method of cooling concrete by supplying cooling water internally, and when concrete is poured into each stage, cooling piping is installed in the space of the stage where concrete is to be poured, and is placed outside the stage. A connecting fitting through which cooling water can flow, which has a connecting part to the cooling piping and a connecting part to the cooling water supply means, is removably attached to the molded plate in a penetrating manner, and the cooling piping is connected to the connecting fitting. After that, concrete is poured into the relevant step, and during pouring, the cooling water supply means is connected to the cooling piping via the connecting tool with the connecting tool attached to the template,
A method for cooling poured concrete in the construction of a large concrete structure, characterized in that the template is then removed and a cooling water supply means is connected to cooling piping.