JPS5822604B2 - Ground improvement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ground improvement method, particularly to a method for hardening and stabilizing soft ground.

Conventionally, methods such as sand pile construction and sand pile consolidation methods have been proposed to improve soft ground, but since soft ground generally retains a large amount of moisture, sand piles such as those described above do not remove surrounding moisture. It was not possible to stabilize the entire ground evenly, and it was also impossible to stabilize the deep part of the ground.

This invention was made with the aim of providing a construction method that can effectively improve soft ground, which could not be done using conventional construction methods. The purpose is to provide a construction method that allows press-fitting to deep parts.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in the figure, a casing 1 made of a pipe is provided with a screw 2 on its lower outer circumferential surface, and a plurality of closing lids 3 are attached to the lower end by a hinge structure.

Each closing lid 3 has a conical shape when closed, and an old body 4 with the conical tip facing down is detachably attached to the lower end of the group of closing lids 2.

A screw 5 is incorporated inside the casing 1, and the casing 1 and the screw 5 can be individually rotated in forward and reverse directions by an auger motor 6.

The screw 5 is inserted into the casing 1 with an opening "17" at the -L end.
In addition to pressure feeding the expandable solidifying material A by absorbing moisture, which has been introduced from the casing 1, the closing lid 3 is pushed open when the casing 1 is pulled out.

This screw 5 occupies as little space inside the casing 1 as possible.
The inside of the shaft portion 8 is hollow and serves as an air passage, and an injection hole 10 for feeding air into the casing 1 is provided at an appropriate position.

A jack 11 that gives elasticity to the screw 5 is provided at the upper end of the screw 5. When the jack 11 is extended when the casing 1 is pulled out, the lower end of the screw 5 can push open the closing lid 3. It is now possible to do so.

In the case of the jack 11 shown in FIGS. 2 and 3,
A screw structure is shown in which a bright part 13 is fixed to a shaft 12 driven by an auger motor 6, and a threaded shaft 14 that is screwed onto the bright part 13 is attached to the upper end of the shaft part 8 of the screw 5.

Further, the jack 11 can be a hydraulic mechanism as shown in the example shown in FIG. 12, and such a hydraulic mechanism is preferable since it is not related to rotation (the screw can be expanded and contracted).

Note that since air is blown into the casing 1 through the screw 5, the open lower portion of the casing 1 can be closed.

Further, as the expandable solidifying material A supplied into the casing 1, a mixture of cement and gypsum is used.

Next, the construction sequence of this invention will be explained based on FIGS. 4 to 11.

First, as shown in FIG.
The casing 1 with the attached screw 2 is erected at the required position on the ground, and then the auger motor 6 is started to give the casing 1 rotation (normal rotation) in the screwing direction of the screw 2, and the casing 1 is erected into the ground as shown in Fig. 5. make an approach.

As shown in Fig. 6, when the casing 1 reaches a predetermined depth, the expandable solidifying material A is introduced into the space secured inside the casing 1 using the hopper 15 facing the open lower as shown in Fig. 7. .

When a predetermined amount of solidifying material A is put into the casing 1 as shown in Fig. 8, the screw 5 is connected to an air supply source as shown in Fig. 9, and in this state, the casing 1 is slightly reversed to Pull the closure lid 3 away from the combination 4.

Next, the jatsugi 11 is extended, the closing lid 3 is pushed open, and after opening the closing lid 3, the screw 5 is rotated in the direction of press-fitting into the assimilated material by the auger motor 6, and the ejection hole 1 is rotated by the auger motor 6.
Air is blown into the casing 1 from 0, and the casing 1 is further rotated (reversely) in the pulling direction.

At this time, the casing 1 and the screw 5 rotate in opposite directions.

By blowing air, the friction between the blades 9 and the solidified material A is reduced, and the solidified material A is effectively press-fitted.

The casing 1 and the screw 5 rise together, and as shown in FIG. When exposed in the ground,
Assimilation material A absorbs moisture in the ground, expands and solidifies due to this moisture absorption, and compresses the ground in the radial direction.

When the pulling out of the casing 1 is completed, as shown in Fig. 11,
Columnar bodies B are formed by the expandable assimilated material A, and the ground is strengthened and stabilized, and the surrounding moisture is also reduced, resulting in hardening.

As described above, according to the present invention, a telescopic screw is built into the casing, and the expandable solidification material that absorbs water is compacted into the casing. The casing expands in the radial direction and solidifies while compressing the ground. Moreover, the casing secures a space inside, and is inserted into the ground with a conical tip that can be opened and closed and a combination attached to this tip. After insertion, the screw Since the tip is opened by elongating the column, it is possible to form a columnar body that reaches deep into the ground, thereby effectively strengthening and stabilizing the soft ground.

Furthermore, since the columnar bodies are formed using an expandable solidifying material that absorbs water, the moisture in the ground is absorbed by the columnar bodies, and the ground itself is also solidified.

Furthermore, when the expandable assimilated material is consolidated by the screw, air is ejected from the screw, which reduces the frictional resistance between the screw and the assimilated material, and also pressurizes the solidified material downward. Consolidation into the ground can be performed effectively.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of the equipment used to carry out the improved construction method according to the present invention, Fig. 2 is an enlarged sectional view showing the jack in the contracted state in -L, and Fig. 3 is an enlarged sectional view showing the same in the extended state. , FIG. 4 to FIG. 11 are explanatory diagrams showing the construction order of the construction method of the present invention, and FIG. 12 is a sectional view showing another example of the jack. 1 is a casing, 2 is a screw, 3 is a closing lid, 4 is a combination, 5 is a screw, 6 is an auger motor, 7 is an opening, 8
9 is the shaft, 9 is the blade, 10 is the injection hole, and 11 is the jack.

Claims (1)

[Scope of Claims] 1. An old body is removably attached to a conical tip formed to be openable and closable, and a casing with a retractable screw incorporated therein is inserted into the ground with the screw in a contracted state, and the casing is inserted into the casing. After securing a space in the casing and filling the space inside the casing with an expandable solidifying material by absorbing moisture, the tip of the casing is opened by expanding and contracting the screw, and then the screw is rotated to pump out the expanding solidifying material. A ground improvement method characterized by forming a columnar body underground by extruding the casing into the ground through the opening at its tip and pulling the casing out. 2. The old body is removably attached to the conical tip that can be opened and closed, and the casing has a screw built into it that can expand and contract freely and allows air to be blown out from the shaft.
A space is secured in the casing by inserting the screw into the ground in the contracted state, and after filling the space in the casing with an expandable solidifying material that absorbs moisture, the tip of the casing is opened by expanding and contracting the screw, and then It is characterized by blowing air from the screw into the casing and rotating the screw to force-feed the expandable solidified material and extrude it into the ground from the opening at the tip of the casing, and by pulling out the casing to form a columnar body in the ground. Ground improvement method.