JPS5929738B2 - Shallow foundation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a construction method for small and shallow foundations such as foundations for traffic signs and guardrails.

Conventionally, when erecting traffic signs on roads, the procedure was (1)
) Cut out the asphalt, (2) Remove the earth and sand beneath it and dig a hole, (3) Assemble a concrete wooden frame in the hole, (4) Pour concrete into the wooden frame, (5)
After the concrete hardens, the wooden frame is removed and earth and sand is refilled around the concrete foundation, which involves many steps and takes a long time.

This invention aims to simplify the process and shorten the time required by making it possible to pour concrete without a wooden frame by press-fitting a drilling frame compatible with concrete foundations into the ground while vibrating it. The details will be explained based on the illustrated embodiment as follows.

1 to 4 show each step of the method of this invention. First, as shown in FIG. 1, a cutter 2 is used to cut out a desired portion of the asphalt layer 1 on the ground surface.

Next, as shown in FIG. 2, a drilling frame 4 is placed on the exposed surface of the earth and sand 3, and is pressed into the ground while being vibrated.

Specifically, a breaker 6 is attached as an attachment to the tip of a boom 5 of an excavator, etc., and this breaker 6
The drill part is attached to the drilling frame 4, and while the entire drilling frame 4 is vibrated by the operation of the breaker 6, the drilling frame 4 is press-fitted into the ground by pressurizing the boom 5.

The drilling frame 4 has the same external shape as the concrete foundation 7 to be cast into the ground, and can be formed into various shapes such as a short cylindrical shape and a prismatic shape depending on the shape of the concrete foundation. The drawing shows a prismatic drilling frame 4.

As shown in FIG. 5, its structure is such that a bottom plate 10 is fixed to the lower end of a support shaft 9 which has a mounting part 8 for the breaker 6 at the upper end, and a side plate 11 is attached to the periphery of the bottom plate 10.
: The bottom plate 10 has the same external shape as the concrete foundation 7, and a connecting rod 12 that can be expanded and contracted is provided radially between the support shaft 9 and the side plate 11.

The connecting rod 12 has its base 13 rotatably fitted into a fitting recess 14 protruding from the support shaft 9, and its threaded portion 15 at its tip is screwed into a female threaded body 16 fixed to the side plate 11. By rotating this rod 12, the distance between the upper part of the side plate 11 and the support shaft 9 can be changed and adjusted.

Incidentally, the outer surface of the side plate 11 is tapered slightly upwardly to make it easier to pull out the drilling frame 4 from the ground.

By press-fitting the drilling frame 4 into the ground by approximately its height, a foundation hole 17 with the same external shape as the drilling frame 4 is created in the ground as shown in Figure 3. Since vibration and pressure are applied to the earth and sand around the frame 4, the earth and sand on the bottom and side walls of the foundation hole 17 are firmly compacted.

This invention focuses on the hardness and denseness of the peripheral wall of the foundation hole 17 formed as described above, and attempts to use the foundation hole 17 itself as a frame for pouring concrete. Concrete is poured directly into the foundation hole 17 after it has been pulled out, and the pillar 18 of the road sign is erected.

When the concrete foundation 7 hardens, construction is completed.

In some cases, an asphalt layer may be provided on the concrete foundation 7.

In addition, when the asphalt layer 1 is thin in the above process,
The cutting process may be omitted, and the drilling frame 4 may be placed directly on the asphalt layer and pressurized to push the unnecessary portion of the asphalt layer into the ground.

The method of this invention consists of the above-mentioned steps, and since concrete is poured directly into the drilled foundation hole using a drilling frame, there is no need to assemble a wooden frame for concrete pouring underground as in the past. , not only can materials for the wooden frame be saved, but the construction process can be greatly simplified by eliminating the need for assembling the wooden frame, removing the wooden frame after the concrete has hardened, and backfilling with earth and sand. Construction time and labor can be saved.

[Brief explanation of drawings]

1 to 4 are explanatory diagrams showing each step of the method of the present invention, and FIG. 5 is a longitudinal sectional view of the drilling frame. 1... Asphalt layer, 3... Sediment,
4...Drilling frame, 7...Concrete foundation, 17...Foundation hole.

Claims (1)

[Claims] 1. A foundation in which a hole frame with the same external shape as the concrete foundation to be poured into the ground is placed at a desired position on the ground surface, and the hole frame is pressed into the ground while vibrating, and the surrounding wall portion is tamped. A shallow foundation construction method in which a concrete foundation is formed by drilling a hole and pouring concrete directly into the foundation hole from which the drilling frame has been pulled out.