JPS60109421A - Tremie tube for placing underwater concrete - Google Patents

Abstract

PURPOSE:To prevent the separation of concrete when transferring it from a tremie tube to other tremie tube by a method in which the tremie tube is designed to have a double structure with an inner tube and an outer tube, and a valve provided at the lower end of the inner tube is opened or closed by vertical movement of the tremie tube. CONSTITUTION:When a tremie tube of a double structure with an inner tube 10 and an outer tube 12 is in the state of being hung down in water 34, the inner tube 10 is positioned at the uppermost position of the outer tube 12 and a valve 14 is closed to prevent the discharge of concrete 36 to the outside. When the tremie tube is lowered and the outer tube 12 reaches the ground 38, the inner tube 10 slides on the inner surface of the outer tube 12, the valve 14 is opened by the weight of the concrete 36, and the concrete 36 is discharged through the opening 30 of the outer tube 12. When the inner tube 10 is pulled up, the valve 14 comes into contact with the inner surface of the outer tube 12 to close the inner tube 10, and intrusion of water into the concrete 36 and the separation of the concrete 36 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in Remy pipes 1 to 1 for underwater concrete placement.

Traditionally, for example, bridge piers make up the lower part of a bridge.

When constructing concrete structures such as abutments in water, the sea, or muddy water, concrete is placed in these liquids.

In this type of method, the tremie method using a hollow cylindrical tremie tube is relatively widely adopted. In the tremie method, concrete 1 is usually poured with the tip of the tremie pipe slightly penetrating into the concrete that has already been poured, so there is always enough concrete 1 inside the tremie pipe to balance the water pressure on the outside. The pipe is columnar, and concrete equivalent to m supplied from the upper end of the tremie pipe is discharged from the tip.

When pouring progresses and the specified amount of concrete has been placed, it is necessary to stop pouring concrete, pull out the tremie pipe, and move it to another location, but the following problems were pointed out at this time: It had been.

That is, as mentioned above, there is concrete 1- in the tremie pipe that balances the outside water pressure, and even in a state where the pouring has progressed, the concrete 1- exists, although the gap becomes slightly smaller.

Therefore, if the inside of the tremie pipe is handled in this state, the balance between the concrete pressure inside the tremie pipe and the water pressure outside will be disrupted.
The heavy concrete tries to fall, and the lighter water tries to take its place in the tremie pipe.

As a result of this replacement, the concrete in the Remy pipes 1 to 1 is washed and separated by the invading water, resulting in significant defects and deposits on the concrete that has already been placed.

As a means to solve this problem, since it is practically impossible to remove the defective part by diving, the tremie tube is composed of a rigid outer tube with slits and a flexible inner tube, and the tip of the inner tube is #ilD by weight of concrete poured in
A double tube structure equipped with leaf springs has been proposed.

However, although this double-tube structure 1 to Remy tube solves the above-mentioned problem at the time of transfer, it has the following drawbacks.

In other words, water pressure is constantly applied to the flexible inner pipe from the outside from the top to the bottom through the slits in the outer pipe, which prevents the concrete from falling smoothly through the inside, and the greatest water pressure is applied to the tip. For this reason, it was difficult to discharge concrete smoothly to the outside against the elasticity of the leaf springs.

This invention was made in view of the conventional problems as described above, and its purpose is to prevent separation of concrete when transferring i-Remy pipes and to enable smooth pouring. The company provides tremie pipes for underwater concrete placement.

In order to achieve this object, the present invention provides a tremie pipe for underwater concrete placement, in which the tip of the tremie tube has a double structure consisting of hollow rectangular inner and outer tubes, and the inner tube has a tip end attached to the outer tube. A valve body is provided which enters the inner pipe and locks the inner pipe so as to be movable up and down, and which opens and closes the inner pipe. The underwater concrete filled in the inner pipe is discharged to the outside through the outer pipe through the opening of the valve body.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a tremie pipe for underwater concrete placement according to the present invention.

This figure is an exploded perspective view of the distal end of the tremie tube, and the distal end of the tremie tube has a double structure of an inner tube 10 and an outer tube 12, both of which are formed into a hollow rectangular shape. The inner tube 10 is formed to have a slightly smaller cross section than the outer tube 12, and its distal end enters the outer tube 12 and is locked in a vertically movable manner. A pair of openings are provided, each of which has a valve body 14 having a fan-shaped cross section so as to close the opening.
The valve body 14 is hingedly connected to the side wall of the valve body 14 so as to be swingable, and a flat elastic piece 32 is fixed to each of the arc-shaped ends 4- of the valve body 14.

On the other hand, the outer tube 12 is narrowed down at a predetermined interval in the vertical direction on opposing side surfaces at approximately the center in the axial direction to form a stepped portion 16.16, and this stepped portion 16-16
A pair of openings 18.18 are formed by cutting out the gap, and the vertical length of the openings 18.18 is approximately the same as the arc diameter of the valve body 14, and the width thereof is approximately the same as the width of the valve body 14. They are the same.

Further, a flange portion 20 that expands outward is formed at the upper end of the outer tube 12, and this flange portion 20 is provided with a flange portion 20 that expands outward.
A stopper piece 22 protruding along the outer periphery of the inner tube 12 is in contact with the upper part of the valve body 14, and a stopper piece 22 that is attached to the inner surface near the upper end of the outer tube 12 engages with the hinge portion 24 of the valve body 14. A mating claw piece 26 is provided in a protruding manner.

Further, an anchor material 28 wider than the outer tube 12 for preventing traction is fixed to the tip of the outer tube 12, and
The distal end side walls of the outer tube 12 are each cut into a substantially U-shape,
A through hole 30 is provided for discharging underwater concrete to the outside.

When the inner tube 10 is installed in the outer tube 12 from the above-described configuration,
Flange portion 20 of outer tube 12 and stopper piece 2 of inner tube 10
2 are in contact with each other, and the hinge portion 24 of the inner tube 10 and the outer tube 1
The inner tube 10 can move up and down between the state in which the second claw piece 26 engages, and the valve element 14 opens and closes the inner tube 10 in accordance with this up and down movement. This will be explained using figures.

First, as shown in FIG.
At the highest position of the inner tube 10 where the hinge portion 24 of the valve body 14 of the inner tube 10 is engaged, the outer surface of the valve body 14 is in contact with the inner surface of the outer tube 12. Each valve body 14 is pushed inward and the inner tube 10 is closed.

In this state, even if the inner pipe 10 is filled with concrete to be cast, it will not open. Then, the inner pipe 10 gradually descends, and at the lowest position where the stopper piece 22 of the inner pipe 10 and the flange part of the outer pipe 12 come into contact, the hinge part 24 of the valve body 14 is provided on the outer pipe 12. Step part 1
6, this valve body 14 corresponds to the opening 18 which has approximately the same external shape as the valve body 14. If the inside of the inner pipe 10 is filled with concrete, the valve body 14 will be in contact with the hinge part 24 due to its gravity. If a spring member is provided that urges the valve body 14 outward, its elastic force causes the inside of the opening 18 to swing outward, thereby opening the inner pipe 10.

Next, a method of placing concrete underwater using the tremie tube having the above-described structure and operation will be described.

FIG. 3 is a schematic diagram without showing the order of the steps.

First, the tremie pipe is installed in the water 34, concrete 36 is filled in the interior 10, and the tremie pipe is suspended by an appropriate means such as a crane (see FIG. 3(a)).

In this state, the inner tube 10 is in relation to the outer tube 12 as shown in FIG.
As shown in a), since the valve body 14 is at the highest position, it is not open, so that the concrete 1-36 is not discharged to the outside, and the surrounding water does not enter.

Further, by filling the inner pipe 10 with concrete 36 and suspending it, the weight of the concrete 36 can be opposed to the buoyant force acting on the tremie pipe, which is extremely convenient.

Next, the tremie tube is gradually lowered until the outer tube 12 reaches the submerged ground 38, and when lowered further, the inner tube 10 reaches the position shown in FIG.
In the state shown in b), the valve body 14 opens due to the weight of the concrete 36, and the concrete 34 is discharged in a substantially horizontal direction through the through hole 30 of the outer tube 12 (Fig. 3 (b)
reference).

Then, when a predetermined amount of concrete 34 is discharged,
- Pull up the inner tube 10, close the valve body 14, stop the discharge, pull up the outer tube 12 a little upwards, lower the inner tube 10 again, and continue pouring concrete 34 (see FIG. 3(c)).

In this case, an anchor material 28 for preventing upwelling is fixed to the tip of the outer tube 12, and the upper surface of the anchor material 28 is covered with the poured concrete 40, so that the outer tube 1
2 is prevented from rising.

When the concrete 34 is placed in a predetermined amount, it is necessary to transfer the tremie pipe, which is done by stopping the concrete 340 injection, pulling up the inner pipe 10, and moving the inner pipe 10 to the outer surface of the valve body 14. When the inner tube 10 is closed by contacting the inner surface of the outer tube 12 and the inner tube 10 is further pulled up, the state shown in FIG. The outer tube 12 can be separated from the existing concrete 40 while still being filled with concrete 34 sufficient to balance the outside water pressure, and can be smoothly transferred to another pouring location (see Figure 3 (d)). .

Even during this transfer, since the concrete 34 is filled in the tremie tube, the buoyancy acting on the tremie tube can be counteracted and the movement can be made smooth.

In the above embodiment, only the distal end portion of the inner tube has been described, but the other portions may have various shapes such as two circles.

In addition to ordinary concrete, it is of course possible to use a highly viscous concrete to which a mixture for reducing separation is added as the concrete for pouring.

Roughly speaking, an anchor material 2 is fixed to the tip of the outer tube 12.
8, a through hole 42 may be provided as shown in phantom lines in FIG. 1 so that the poured concrete is discharged in the vertical direction.

As explained in detail in the embodiments above, the tremie pipe for underwater concrete placement according to the present invention can be used by filling the pipe with concrete before it is installed and moved, thereby counteracting the buoyant force acting on the tremie pipe. This makes these operations easy and smooth.

Additionally, when the tremie pipe is transferred, water can be prevented from coming into contact with the concrete remaining inside the pipe by blocking the inner pipe with a valve body, which prevents the concrete from being placed separately and resulting in significant defects. do not have.

Furthermore, since the tremie tube is a rigid hollow body, the poured concrete inside the tube can be discharged smoothly even when surrounding water pressure is applied, and the tremie tube can be opened and closed simply by moving the inner tube up and down. This allows quick pouring.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of the distal end of the tremie tube according to the present invention, FIG. 2 is an explanatory diagram of the opening/closing operation of the tremie tube, and FIG. 3 is an explanatory diagram of how to use the tremie tube. 10...Inner pipe 12...Outer pipe 14...
... Valve body 16 ... Step portion 18 ...
・Opening 20...Flange part 22...
Stopper piece 24... Hinge part 26...
... Claw piece 28 ... Anchor material 30 ...
・Through hole 32...Elastic piece 34...Underwater 36...Concrete 38...Ground 40...Existing concrete Patent applicant Co., Ltd. Obayashi Attorney Patent Attorney - Kensuke Iro 3rd (a) (b) (c) Cd) /#! ／ //'W 8

Claims (2)

[Claims] (1) In a tremie pipe for underwater concrete placement, the tip of the tremie tube has a double structure consisting of a hollow rectangular inner and outer tube, and the inner tube has its tip inserted into the outer tube to form an outer tube. The valve body locks the inner pipe so as to be movable up and down, and opens and closes the inner pipe. A tremie pipe for placing underwater concrete, characterized in that underwater concrete filled in the inner pipe is discharged to the outside through the outer pipe. (2) An anchor material is fixed to the tip of the outer pipe to prevent upwelling, and a through hole is bored at the lower end of the side wall, and the underwater concrete is discharged through the through hole. A tremie pipe for underwater concrete placement according to claim 1.