JPH0326247B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating extra heap portions in cast-in-place concrete foundation pile construction methods.

Background of the Invention Cast-in-place concrete piles often use muddy water such as bentonite suspension, so at least 50 cm (excluding the rain trough) at the top of the concrete is used.
It is stipulated that concrete should be poured taking into account the above-mentioned extra heap portion, and that this portion should be removed when processing the pile cap later [1].

In the past, such areas were generally sealed with breakers, but this method not only generates noise and vibration, but also risks damaging the concrete pile cap.

To date, the following construction methods have been proposed to avoid the above-mentioned noise and vibration. In other words, "Figure 1" is an explanatory diagram thereof, and 10 is the entire reinforcing bar cage,
12 indicates the erector muscle, and 14 indicates the hoop muscle. Reference numeral 16 denotes a pipe containing a crushing agent, which is rolled into a hoop shape and placed inside near the upper end of the reinforcing bar cage, which corresponds to the lower end of the extra heap. Moreover, a hollow pipe 18 for edge cutting is inserted on the outside thereof. Also, standing muscles 1
2 is also covered with a plastic pipe 20 for edge cutting.

After a certain period of time has elapsed after the concrete is placed, the crushing agent undergoes a hydration reaction, creating a very large expansion pressure. This expansion creates a crack 22 in the concrete, which separates the reinforcement portion 26 from the concrete column 24, allowing it to be pulled out by a machine [2].

However, with this method, (1) it takes a very long time to generate the necessary expansion pressure, (2) it is difficult to handle the crushing agent at the work site, and (3) the crushed concrete is relatively large. Furthermore, there are problems such as the need for repeated crushing treatment to break down into small pieces.

Therefore, the object of the present invention is to provide a method for treating the excess heap portion that is easy to handle on site, does not damage the concrete pile, and does not cause pollution during the work.

Structure of the Invention As shown in "Figures 2 to 5", (1) A pipe 56 for edge cutting is placed over the upper end of the vertical bar 12 of the reinforcing bar cage 10 that has been placed in advance in the excavated hole. (2) A crushing device 3 in which a plurality of hydraulic jacks 34 each having a ram 38 having a conical or pyramidal tip protrude horizontally and radially on the same horizontal plane.
(3) Then, operating the hydraulic jack 34,
The present invention is characterized in that the ram 38 is moved forward to create a crack 22 on the lower surface of the backfill portion 26, and (4) the crushing device 30 is then lifted up and removed together with the crushed portion of the backfill portion.

Embodiment In "Figures 2 and 3", 30 indicates the entire crushing device used in the present invention. 32 is its main body, which is made of, for example, a hexagonal block. For example, six hydraulic jacks 3 are connected to the main body 37.
4 protrudes horizontally and radially. 38 is a ram, the tip of which has a conical shape 40 as shown in Figure 4a, or a lower surface 43 as shown in Figure 4b.
It is shaped like a flat triangular pyramid 42.

44 is a guide pipe for lifting, the lower end of which is fixed to the main body 32, and a hydraulic hose 46 (which leads to the jack 34) is placed inside the guide pipe. For example, an iron plate 4 is attached to the bottom surface of the jack 34.
8 is fitted, in which a number of holes 50 (for passing concrete) are drilled.

Description of construction method As shown in FIG. 5, the upper end of the guide pipe 44 is supported by a suitable member 52 and suspended from the inner surface of the upper end of the reinforcing bar cage 10. and hydraulic pump 5
Connect 4. Furthermore, a plastic pipe 56 (for example, made of vinyl chloride) for edge cutting is placed over the vertical reinforcement 12. Incidentally, as in the case of "Fig. 1", a pipe 18 for cutting edges in the horizontal direction may be attached.

Concrete is poured in the above condition.

After that, when oil is supplied to the jack 34 and it is operated, the crack 22 is inserted under the excess portion 26 as shown in "Fig. 6". At this time, if the tip of the ram 38 has a pyramidal shape with a flat lower surface 43 as shown in Figure 4b, the crack will not go further below the lower surface of the excess portion. ,
There is no need to break concrete piles more than necessary. In other words, the pile body will not be damaged.

Thereafter, the upper end of the pipe 44 is grasped mechanically and lifted up. Then, the metal plate 48 and the jack 34 hold the excess portion 26 from below and lift it up.

Effects of the invention (1) No noise or vibration is generated. It is also dustproof.

(2) Unlike using chemicals, it is easy to handle and can be done in a short time.

(3) Do not damage the pile concrete below the extra heap.

(4) The crushing device 30 can be used repeatedly.

(5) A pipe for edge cutting is placed over the vertical upper end of the reinforcing bar cage, so that after crushing, the extra heap can be lifted without any problem.

(6) The crushing device is suspended inside the reinforcing steel cage near the top end, and after pouring concrete and making cracks, it is lifted up and removed together with the crushed portion of the reinforcement; It can be pulled out and removed.

In other words, assuming that another crane or the like is used for pulling out and removing, it would be necessary to connect the crushed extra material to the tip of the crane, but in the case of the present invention, such work is not necessary at all. .

[References] (1) Japan Foundation Construction Association, “Cast-in-place concrete pile construction guidelines and commentary (draft)” April 1972
Month (2) Matsushiro et al.: “Pile cap treatment construction of cast-in-place concrete piles using PPC method”, Architectural technology construction,
September 1983, p.59-63.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the prior art, Fig. 2 is a plan view of the crushing device used in the present invention, Fig. 3 is a side view thereof, Figs. 4 a and b are explanatory diagrams of the shape of the tip of the ram, Figures 5 and 6 are explanatory diagrams of the construction method. 10: Rebar cage, 22: Cracks, 26: Excess portion, 30: Whole crushing device, 34: Hydraulic jack, 38: Ram.

Claims (1)

[Scope of Claims] 1. When processing the excess portion of cast-in-place concrete piles, a pipe 20 for edge cutting is placed over the upper end of the vertical bar of the reinforcing bar cage that has been placed in the excavated hole in advance. Along with this, a crushing device consisting of a plurality of hydraulic jacks having rams with conical or pyramidal tips projecting horizontally and radially on the same horizontal plane is suspended inside near the upper end of the reinforcing bar cage to crush concrete. and then driving the hydraulic jack to move the ram forward to create a crack on the lower surface of the backfill portion; and then lifting and removing the crushing device together with the crushed portion of the backfill. A method for processing the excess heap of foundation piles.