JPS6210325A - Foot protecting of pile - Google Patents

Abstract

PURPOSE:To increase bearing capacity of a pile by method in which a pile driven, and cement-based hardener is injected through an injection tube connected with a cloth cylinder near the foot of the pile through the hollow of the pile to form an expanded foot protection sphere. CONSTITUTION:A cloth cylinder 6 is covered on the foot portion of a pile 2 and clamped with a band 7. An injection tube 3 through which a cement hardener is injected into the cylinder 6 is provided in the hollow of the pile 2, and its lower end 4 is fixed to the pile 2. The pile 2 is settled to a given depth, and soil cement mortar 8 is injected through the tube 3 into the cylinder 6 to form a soil cement spherical footing 9.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a pile tip cementing method for embedding hollow piles such as concrete piles and steel pipe piles.

The conventional pile embedding method uses a bare auger to disturb the ground compared to the percussion method, so the bearing capacity of the pile is small, and since the ground must be excavated before the pile is sunk, excavated soil is discharged. had to be disposed of. On the other hand, in order to improve the bearing capacity of the pile tip, enlarged excavation of the pile tip using an enlarged blade or ultra-high pressure generator (K) was carried out to create an enlarged bulb at the pile tip, but the ground around the enlarged bulb was loosened. Therefore, its supporting capacity was not fully demonstrated.

Problems to be Solved by the Present Invention The present invention seeks to simultaneously solve the problem of the small bearing capacity of a pile peculiar to an embedded pile as described above, as well as the problem of disposal of discharged earth and sand.

Means to solve problems In the present invention, after the pile is sunk, it is passed through the hollow part of the pile.

This pile tip root consolidation method is characterized by creating an expander-hardened bulb near the pile tip by injecting cement hardening material through an injection pipe connected to a cloth cylinder near the pile tip.

EXAMPLE An example of the present invention will be explained with reference to drawings according to its construction procedure.

First, in order to sink the pile, the ground is excavated or turned into mud using an earth auger, water, etc., and the excavated hole l shown in Figure 2 is created. At this time, the discharged earth and sand is stored in containers as necessary, and if there is too much moisture, the moisture content is reduced by making use of sedimentation of soil particles, etc.

Once the excavation or muddying of the ground is completed, the pile bodies 2 are then erected and sunk to a predetermined depth while being sequentially joined.

At this time, a cloth cylinder 6 is placed over at least the vicinity of the tip of the lowermost pile, and both ends of the cloth cylinder are tightened using pile banding tools. Also.

In the hollow part of this pile, a small-diameter injection pipe 3 for injecting a cement hardening material such as cement mortar, cement milk, soil cement mortar, etc. from the above-ground part into the cloth cylinder is arranged in advance. The lower end 4 is fixed to the antibody and is arranged so that a cement hardening material can be injected through the antibody between the stake and the fabric cylinder. The method of fixing the antibody to the lower end of the injection tube 4 is as shown in FIG.
It is best to use a T-shaped tube near the center of the tube so that it can be injected in two directions.

As the cloth cylinder used here, it is preferable to use one obtained by processing a civil engineering sheet made of ordinary synthetic fiber or the like into a cylinder shape. The injection pipe placed in the hollow part of the pile can be any type of pipe, such as water supply steel pipe or plastic pipe, and it is best to join the injection pipe at the same position before joining the pile joint.

When the pile is sunk to a predetermined depth, the above-ground part 5 of the injection pipe is connected to a pump such as a mortar pump, and in this embodiment, a predetermined amount of soil cement mortar 8 is injected, and the fabric cylinder is inserted into the pipe as shown in the 1st mK. It is expanded to a predetermined size, and the surrounding ground loosened during excavation is recovered by the expansion of the cylinder.

Fill cement mortar is made by mixing discharged earth and sand with cement and the required amount of water. The amount of earth and sand mixed at this time should be less than the maximum amount that does not prevent the fill cement mortar from sufficiently hardening.

Zo at 1 to 4 times the amount of normal cement, 4 week compressive strength.

If/csl is a rough guideline. If there is too much water in the injected fill cement mortar, it is possible to dehydrate only the water from the cloth-like cylinder and make a solid fill cement. On the other hand, if the water permeability of this cloth-like cylinder is too high, it is also possible to coat part or all of this cylinder with a rubber resin, acrylic resin, etc. to make it semi-water permeable.

These fill cement mortar is injected to create a complete soil old ment bulb 9 which is restrained by a cloth-like cylinder at the tip of the pile. Only the water in the mail cement mortar is dehydrated through the cloth-like material of the cloth-like cylinder, resulting in a strong fill cement.

At this time, the injection is controlled using a pressure gauge and injection amount depending on the type of ground.

The outer diameter of the tip bulb completed using this method is the pile diameter 12)
The length is preferably 1.5 to 2.5 times the pile diameter, and the length is preferably 2 to 10 times the pile diameter. If it is 1.5 times or less, the supporting capacity is insufficient II),
If it is 2.5 times or more, not only will the injection amount increase, but the area to be excavated in advance will be too large and will take time.

Also, in terms of the bearing capacity of the pile material, no greater bearing capacity is required.

Effects of the Invention The pile tip root consolidation method according to the present invention makes it possible to sufficiently reliably create an enlarged bulb by using a cloth cylinder and an injection pipe for the pile to improve the pile tip supporting force, which was previously unreliable.

In other words, by protecting the expanded cement milk bulb with a cloth-like material, it is possible not only to create a perfectly shaped bulb, but also to expand the surrounding ground that has been loosened during excavation due to the expansion of the cloth cylinder, thereby providing stronger ground. This made it possible to do so. In addition, if the earth and sand discharged during excavation is mixed with cement and injected into the cylinder, the problem of discharge disposal can be solved. Also,
If the fill cement mortar has a high water content, it is possible to obtain a strong soil cement cured product by dehydrating the excess water using combination K with cloth.

[Brief explanation of drawings]

Figure wi1 shows a completed view of the pile tip root consolidation method of the present invention. FIG. 2 is an explanatory diagram of the pile tip root consolidation method of the present invention, showing the state immediately before pouring soil cement mortar 8. l...Drilling hole, 2...Pile body, 3--Injection pipe, 4...
- Lower end of the injection pipe, 5--Above-ground part of the injection pipe, 6... Cloth cylinder. 7.°° Band s8... Soil cement mortar, 9
... Fill cement bulbs. Patent applicant: Asahi Kasei Industries, Ltd. Figure 1 Figure 2

Claims (1)

[Claims] After the pile has been sunk, cement hardening material is injected through the hollow part of the pile through an injection pipe connected to a fabric cylinder near the pile tip, thereby creating an enlarged root hardening bulb near the pile tip. Pile tip root consolidation method featuring