JPS5910883B2 - Concrete pile manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves holding a formwork for producing concrete piles with a split structure so that the splitting surface is positioned almost vertically, inserting a concrete pressure nozzle into the formwork from the injection end of the formwork, and By causing the concrete discharged from the nozzle to flow backward from the tip of the nozzle to the pouring end side of the formwork, the nozzle and/or the formwork is inserted in the opposite direction to the insertion direction while maintaining the internal pressure of the concrete at the tip of the nozzle. This invention is a specific invention for a concrete pile manufacturing method characterized by moving the concrete pile relative to the concrete pile, and its purpose is to save labor and improve the quality of concrete pile manufacturing.

To explain the embodiment of the present invention shown in the drawings, a bogie 2 is supported on an inclined rail 1 with a chain or wire rope 3 so as to be able to rise and fall freely, and the bogie 2 is wound up and unwound with a winding machine 4. can be supported along the inclined rail 1 so as to be able to rise and fall freely.

A formwork 5 for manufacturing concrete piles that is long in the inclination direction is supported on this cart 2, and a device for preventing backflow concrete from flowing out is provided at the upper end of the formwork 5, and the device can freely open and close a sealing lid 6 for inserting a nozzle. The shutter 7 of the formwork 5 is pivotally supported 8 slightly below the lid 6.

The airtight lid 6 has a double door plate 6' as shown in FIGS. 6 to 9.
, 6' has a nozzle insertion hole 24 therein.

The nozzle 9 is supported by a stand 10 parallel to the inclined rail 1, and is connected to a concrete pump (piston pump) 12 through a pipe 11.

In addition, what is shown by 13 in the figure is a concrete mixer, 14 is a hopper, 15 is a lower end fixing plate, 16 is an upper end fixing plate,
17 is a PC steel rod, 18 is a cylinder for rotating the shutter 70, and the shutter 7 is closed by the pressing force of the cylinder 18.

In the present invention, when the formwork 5 is moved diagonally upward by the winding machine 4, the nozzle 9 moves from the upper end opening of the formwork 5 to a position close to the lower end fixing plate 15 of the formwork 5 (with the airtight lid 6 open). The concrete 19 mixed by the mixer 13 is pumped to the nozzle 9 by the piston pump 12 and discharged from the tip of the nozzle 9.

As shown in Fig. 2, the discharged concrete 19 flows backward from the tip of the nozzle 9 to the upper end side of the formwork 5, and the reverse flow rate W is detected by the set pressure sensing device of the relief valve provided in the piston pump hydraulic circuit. 12, the piston is stopped so as not to force feed above the set pressure, and the above pressure feed is achieved by lowering the form 5 by unwinding the winding machine 4 and gradually increasing the distance between the fixing plate 15 and the tip of the nozzle 9. is resumed and the backflow amount W is kept almost constant while the same formwork 5
The inside is filled with concrete 19, and the internal pressure corresponding to the above-mentioned backflow amount W is maintained.

The formwork 5 contains reinforcing bars or prestressed steel wires 17, and the concrete 19 discharged from the nozzle 9 passes between these and fills the formwork 5, so the concrete 1, 1-N9 becomes fluid. Although it is necessary to use a material with good properties, it is effective to increase the fluidity of the concrete 19 by vibrating the formwork 5.

As the concrete backflow rate increases, the pumping resistance of the concrete increases and the internal pressure of the concrete in front of the nozzle increases.

When the backflow amount reaches a certain amount, the trolley 2 is moved backward to reduce the backflow amount W.
Concrete filling is carried out while keeping the value almost constant.

The air in the formwork 5 is forced out by the concrete to the formwork opening (upper end).

Press-fitting the formwork 5 at an angle ensures that the air is forced out by the concrete 19, and is extremely effective in reducing the amount of trapped air inside the formwork 5.However, some air bubbles on the surface of the product can seriously hinder the quality of the product. If not, the formwork 5 may remain horizontal.

The formwork 5 is divided into two parts along a vertical plane passing through its center line, and opposing flanges 22, 22 along the vertical plane are attached to the formwork 5.
A dividing surface 23 is formed by the flanges 22, 22.

By positioning the dividing surface 23 in the vertical direction and press-fitting the concrete, air near the dividing surface 23 can escape to the outside of the formwork 5 through the gap between the dividing surfaces 23.

In particular, when manufacturing products with uneven cross-sections such as knot piles using this method, air holes are required because air 21 is trapped in the knots 20, as shown in Figure 2. By holding the formwork 5 so that the dividing surface 23 is positioned almost vertically, the gaps in the dividing surface 23 serve as air vents, and while ordinary air holes act as points, the dividing surface 23 Since it acts as a line, it is superior in that it can expel air more reliably than normal air holes.

When backflow concrete reaches the upper end of the formwork, the outflow prevention device is activated to prevent backflow concrete from flowing out from the upper end of the formwork.

As shown in FIG. 4, the outflow prevention device is constructed to close the gap between the nozzle 9 and the upper end of the mold.

After the backflow concrete reaches the upper end of the formwork and the formwork is filled with concrete 19, until the nozzle 9 comes out of the shutter 7, the amount of concrete discharged is only equivalent to the nozzle volume. The concrete pressure inside the formwork is kept constant by the action of the installed IJ valve, and when the nozzle tip stops between the shutter 7 and the outflow prevention device, the shutter 7 is closed, thereby reducing the concrete pressure inside the formwork. Concrete press-fitting can be completed while maintaining 419 at the required pressure.

Since the present invention is based on the above-mentioned manufacturing method, since the concrete 'J-N9 is kept in a pressurized state within the formwork 5, a dehydration phenomenon occurs in which water in the concrete oozes out from the gaps between the formwork division surfaces. This dehydration phenomenon not only reduces the water-cement ratio of the concrete in the formwork and contributes to increasing the strength of the concrete, but also has the effect of preventing volume reduction and roughening of the product surface due to breathing, which is normally seen in concrete with good fluidity. .

Furthermore, by curing the concrete under pressure, not only is the strength increased compared to that under atmospheric pressure, but also it is possible to prevent shrinkage cracks that are considered inevitable in concrete products. It is possible to mass-produce concrete piles of good quality and save labor by omitting surface troweling of the product.

[Brief explanation of drawings]

Fig. 1 is a side view showing an apparatus according to the concrete pile manufacturing method of the present invention, Fig. 2 is a side view of the concrete dispensing state, Fig. 3 is a vertical cross-sectional view taken along line A-A in Fig. 2, and Fig. 4 is a mold Figure 5 is a side view of the upper end of the frame, Figure 5 is a front view of the shutter, Figure 6 is a front view of the shutter.
7 is a side view of FIG. 6, FIG. 8 is a front view of another example of FIG. 6, and FIG. 9 is a side view of FIG. 8. 9... Concrete pressure feeding nozzle, 5...
・Formwork for concrete pile manufacturing, 19...Concrete, W---Amount of backflow, 23...
・Divided surface.

Claims (1)

[Scope of Claims] 1. A formwork for manufacturing concrete piles having a split structure is held so that the dividing surface is positioned almost vertically, a concrete pressure nozzle is inserted into the formwork from the injection end of the formwork, and concrete is discharged from the nozzle. The nozzle and/or the formwork are moved relative to each other in the direction opposite to the direction of insertion while maintaining the internal pressure of the concrete at the tip of the nozzle by causing the concrete to flow backward from the tip of the nozzle to the pouring end side of the formwork. A concrete pile manufacturing method characterized by moving concrete piles. 2 Hold a formwork for producing concrete piles with a split structure so that the splitting surface is positioned almost vertically, insert a concrete pressure nozzle into the formwork from the injection end of the formwork, and pour the concrete discharged from the nozzle into the nozzle. The nozzle and/or the formwork are relatively moved in the opposite direction to the direction of insertion while maintaining the pressure inside the concrete at the tip of the nozzle by causing the flow to flow backwards from the tip of the nozzle to the pouring end side of the formwork. A method for manufacturing a concrete pile, characterized in that the concrete backflow is prevented from flowing out at the end, and the pressure inside the concrete at the tip of the nozzle is maintained even in the state where the backflow concrete is prevented from flowing out.