JPH0322482B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cylindrical body for constructing compacted sand piles, and is particularly suitable for constructing sand piles by applying complex vibrations including torsional vibrations in soil improvement methods for soft ground. This relates to a cylindrical body for construction.

Conventionally, various construction methods such as the vibrocomposer construction method and the vibroflotation construction method have been provided as construction methods applied to ground with a small N value.

However, these conventional construction methods aim to increase the density of the ground by forcibly replacing the ground to be improved, and have the disadvantage that they cannot increase the resistance to horizontal vibrations such as earthquake forces.

For this reason, the applicant has developed a ground improvement method that applies horizontal torsional vibration in addition to vertical external force to the ground or sand piles to be improved, thereby creating stress and shear history in the ground. It has already been provided in the issue of the bulletin.

The method disclosed in the publication involves fixing a plurality of blade members to the outer surface of the tip of a cylindrical body for sand pile driving, penetrating the blades into the soil to a predetermined depth, and then pouring earth and sand into the cylindrical body. , the cylindrical body is raised by a predetermined amount, the sand inside is passed around from the tip side to the outer surface of the cylindrical body, vibration is applied in the vertical direction at the tip of the cylindrical body, and the sand is applied to the blade member through the cylindrical body. This is a construction method that applies alternating torsional vibration as well as horizontal vibration, and can increase the horizontal strength between the constructed sand piles.

However, the present inventors subsequently studied the above construction method in detail and found that there was room for improvement in the following points.

In other words, since the earth and sand for compacting sand pile construction can only be supplied from the upper end of the cylinder, the earth and sand that is compacted by torsional vibration applied by the blade member is sufficiently circulated to the upper end of the blade member on the outer surface of the cylinder. If the sand piles are not loaded, torsional vibrations will not be effectively transmitted to the earth and sand, and the horizontal strength between the sand piles will not be sufficiently strengthened. It has been found that when alternating torsional vibrations are applied to the blade member, a space is created in the direction opposite to the torsional direction of the blade member, that is, on the front and rear surfaces of the blade member, and that this also does not increase the horizontal strength as intended.

This invention has been made based on the above-mentioned knowledge, and its purpose is to form a through hole that can be opened and closed in a cylindrical body for driving sand piles, and to apply torsional vibration to the cylindrical body. By supplying earth and sand through this hole into the space created when sand piles are created, it is possible to solve the problem of insufficient circulation of earth and sand when constructing sand piles, and to reliably and effectively transmit torsional vibrations to the earth and sand to be compacted.
Thereby, it is an object of the present invention to provide a cylindrical body for constructing compacted sand piles that can reliably improve the horizontal strength between the compacted sand piles.

In order to achieve the above object, the present invention fixes a plurality of blade members to the outer surface of one end, applies complex vibrations including horizontal torsional vibration, and compacts the earth and sand stored inside and the surrounding earth and sand. In the cylindrical body for driving sand piles for creating a sand pile, a through hole bored through the cylindrical body near the upper end of each of the blade members;
A movable lid that opens and closes this through hole is provided, and the earth and sand in the cylinder is supplied through the through hole into the space that is created between the blade member and the compacted earth and sand when torsional vibration is applied to the cylinder. It is characterized by the fact that it becomes like that.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

FIGS. 1a and 1b show an embodiment of a cylindrical body for constructing compacted sand piles according to the present invention.

The cylindrical body 10 shown in the figure is formed into a cylindrical shape with a hollow interior, and is suspended from a crane or the like by a rope 12 at the uppermost end, and has a lower end extending along the axial direction of the cylindrical body 10. A plurality of flat plate-shaped blade members 12, 12 protruding in the radial direction are fixed at equal intervals in the circumferential direction.

The upper end side of the cylindrical body 10 is provided with a fixed chute 18 and a movable chute 20 into which earth and sand 16 for compaction sand pile construction are introduced, and these chute 1
Above the cylinders 8 and 20 are a torsional vibrator 21 for applying horizontal alternating torsional vibrations to the cylinder 10 and a vertical vibrator 22 for applying vertical vibrations to the cylinder 10; ,22
Electric motors 24 for driving the cylinders are loaded in a stacked state, and these structures are the same as those of conventional cylinders of this type, but the cylinder 10 shown in the same figure has the following features. .

That is, as shown in a partially enlarged view in FIG. The cylinder 34 is driven upward from the upper end side of the cylindrical body 10 with oil or air.
is fixed to the outer surface of the cylindrical body 10, and one end of a plunger 36, which is expanded and contracted by this cylinder, is inserted into a guide hole 32 provided at a location where the blade member 14 is fixed to the cylindrical body 10, and this plunger A movable lid 38 is fixed to 36.

In a steady state, that is, when the cylindrical body 10 is inserted or pulled out, or when only vertical vibration is applied, the movable lid 38 is positioned over the through hole 30 to close it. The cylinder 34 is driven to open the through hole 30 only when torsional vibration is applied.

Now, in the case of the cylindrical body 10 having the above-mentioned structure, after penetrating it into the soil to a predetermined depth by an appropriate means, compacted sand pile-building soil is applied via the movable chute 20 and the fixed chute 18. Cylindrical body 10
using the vibrators 21 and 22,
In the case where vertical vibration in the vertical direction and torsional vibration in the horizontal direction are applied simultaneously or alternately, the cylinder 34 is placed in the space created between the blade members 14, 14 and the earth and sand to be compacted, especially when the torsional vibration is applied. By driving and moving the movable lid 38 upward, the earth and sand stored in the cylinder body 10 can be supplied through the through hole 30, so if the earth and sand for the compaction sand pile is insufficiently circulated. But through hole 3
The earth and sand supplied from 0 circulate around the outside of the blade members 14, 14 with the torsional vibration, and insufficient circulation is reliably prevented.

Moreover, this means that the torsional vibration is transmitted to the blade member 14,
Since the compacted sand can be transmitted to the pile-forming earth and sand and the surrounding earth and sand through the entire surface of the pile 14, the horizontal strength of these can be reliably increased.

Furthermore, the space created by torsional vibration becomes smaller as the horizontal strength of the sand pile increases, and therefore the amount of earth and sand supplied to this space gradually decreases.

This means that, for example, if the supply amount of earth and sand is measured by detecting the sand surface within the cylinder 10, the compaction strength of the sand pile to be constructed can be managed.

In the above embodiment, the cylinder 34 and the like for opening and closing the through hole 30 are provided on the outer surface of the cylindrical body 10, but it is of course possible to provide this on the inner surface of the cylindrical body 10.

FIG. 2 shows another embodiment of the cylindrical body for constructing compacted sand piles according to the present invention.

Hereinafter, only the characteristic points of the cylindrical body 10 shown in the figure will be explained. In this embodiment, the cylindrical body 1
A pipe 40 with a nozzle-shaped tip opened in the through hole 30 is attached and extended along the inner surface of the cylindrical body 10 to the upper end. When sending out compressed air to the space, compressed air is sent to this pipe 40, and the earth and sand are supplied to the space along the flow of this air. Even in such a configuration, the same effects as in the above embodiment can be achieved, and the compressed air sent to the pipe 40 can quickly and reliably supply the earth and sand stored in the cylinder 10 to the space. This effect can also be achieved.

In this case, it is also possible to install a normally closed check valve at the tip of the pipe 40 to prevent dirt from entering the pipe 40.

As explained in detail in the embodiments above, the cylinder body for constructing compacted sand piles according to the present invention reliably transmits torsional vibration to the earth and sand to be compacted, thereby ensuring horizontal alignment between the compacted sand piles. It is possible to reliably improve the proof strength.

[Brief explanation of the drawing]

Fig. 1 shows an embodiment of a cylindrical body for constructing compacted sand piles according to the present invention, and Fig. 1a shows its overall view;
Figure b is an enlarged perspective view of the main part of figure a. FIG. 2 is a sectional view of a main part showing another embodiment of the present invention. 10... Cylindrical body, 12... Rope, 14... Wing member, 16... Earth and sand, 18... Fixed chute, 2
0...Moving chute, 21...Torsional vibrator, 2
2... Vertical vibrator, 24... Electric motor, 30... Through hole, 32... Guide hole, 34... Cylinder, 3
6... Plunger, 38... Moving lid, 40...
pipe.

Claims (1)

[Claims] 1 A plurality of blade members are fixed to the outer surface of one end, penetrate into the soil, store the earth and sand inside, and apply horizontal torsional vibration and vertical vibration to compact the earth and sand and the surrounding earth and sand. In the cylindrical body for constructing piles, a through hole bored through the cylindrical body is provided near the upper end of each of the blade members, and a movable cover for opening and closing the through hole is arranged, For constructing compacted sand piles, characterized in that the earth and sand inside the cylindrical body is supplied through the through holes into the space created between the blade member and the earth and sand to be compacted when torsional vibration is applied. Cylindrical body.