JP2789107B2 - Rubber sleeve structure of injection outer tube for ground improvement - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber sleeve fitted to an outer pipe for injecting cement milk into a vertical hole dug in the ground.

2. Description of the Related Art When building a foundation pile for a structure to be built on the ground, cement milk or the like is injected into a vertical hole dug in the ground to strengthen the ground.

At the time of injecting cement milk etc., as will be described in detail later, a rubber sleeve is provided on an outer tube made of synthetic resin,
Cement milk or the like which is fitted so as to close the injection hole formed in the injection outer tube and is press-fitted as the injection outer tube is supplied to the outside of the injection outer tube so as to push out the rubber sleeve from the injection hole. You.

In this case, the conventionally used rubber sleeve 01 was formed from a single rubber layer 02 as shown in FIG.

However, in such a rubber sleeve 01, high pressure due to cement milk or the like is repeatedly applied, and water pressure due to spring water is applied to a deep portion of the vertical hole, so that the rubber sleeve 01 may be damaged.

Means for Solving the Problems and Action The present invention relates to a rubber sleeve structure of a ground improvement injection outer tube which overcomes such difficulties, and provides a rubber sleeve structure for injecting cement milk or the like into a vertical hole dug in the ground. In a rubber sleeve fitted to a tube at a position of an injection hole of the injection outer tube, the rubber sleeve has a cylindrical rubber layer having an inner surface formed by a two-layer cord made of chemical fiber and having an angle of a single fiber. It is characterized by being polymerized differently.

Since the present invention is configured as described above, the rubber sleeve closes the injection hole of the outer injection tube, and is expanded by the pressure of the cement milk or the like from the inside of the injection hole to send the cement milk or the like to the outside. It is possible to supply.

Further, in the present invention, since the rubber sleeve has two layers of cords made of chemical fibers polymerized on the inner surface of the rubber layer, the durability against the pressure of cement milk and the like and the water pressure of spring water is remarkably increased.

Further, in the present invention, since the cords of the two layers are polymerized at different angles of the single fibers, the cords have sufficient strength against pressures from different directions, and have a sufficient strength in the axial direction and the circumferential direction. It can expand and contract freely.

Embodiment Hereinafter, an embodiment according to the present invention shown in FIGS. 2 to 5 will be described.

A group of injection holes 3 is drilled about every 35 cm in the FRP injection outer tube 2 inserted into the vertical hole 1 dug in the ground,
A rubber sleeve 4 is fitted in each injection hole 3 so as to close the injection hole 3.

A plug 8 having a through hole 8c is fitted to the lower end of the pipe 7 on the packer 6, and a first seal member 9 is provided around the outer periphery of the pipe 7 above the plug 8.

Further, a gas pipe 10 is suspended below the plug 8, a plug 11 is provided at a lower end thereof, and a second seal member 12 is provided around the outer periphery of the gas pipe 10 above the plug 11.

A flexible gas pipe 13 extends upward from the upper end of the first seal member 9. Nitrogen gas is supplied to the first seal member 9 through the gas pipe 13, and 1
The seal member 9 and the second seal member 12 are
Are connected to each other so that the nitrogen gas is supplied to the seal member 12 as well.

The plug 8 comprises a cylindrical portion 8a and a flange portion 8b at the lower end thereof. The outer diameter of the cylindrical portion 8a is slightly smaller than the inner diameter of the pipe 7, and is formed into a thickness that can be inserted into the pipe 7 with a margin. The through hole 8c is bent at right angles to the flange portion 8b, reaches a discharge port on the outer peripheral surface of the flange portion 8b, and communicates with the outside.

Further, a gas passage 8d penetrating through the cylindrical portion 8a and the flange portion 8b is formed in the plug 8 so as to extend in the vertical direction, and the upper end of the gas passage 8d is bent in the horizontal direction to form a cylindrical portion. The lower end of the gas passage 8 d reaches the opening on the outer peripheral surface of the plug 8 a, reaches the opening on the lower surface of the plug 8, and communicates with the inside of the gas pipe 10.

A groove is formed in the outer periphery of the cylindrical portion 8a further above the upper end opening of the gas passage 8d in the circumferential direction, and the O-ring 20 is fitted therein.

The plug 8 has its cylindrical portion 8a fitted from below the pipe 7, and the inner peripheral surface of the pipe 7 and the outer peripheral surface of the cylindrical portion 8a are O-rings.
Sealed by 20 and the inside of the pipe 7 and the through hole of the plug 8
8c is communicated watertight.

The cylindrical expansion member 21 of the seal member 9 is
Has an air gap between the outer peripheral surface of the substrate.

The expansion member 21 has an engagement metal fitting 22 on the upper end edge thereof.
It is provided so as to clamp the end by 23,
The engagement fitting 22 is a mounting fitting 24 fitted on the outer peripheral surface of the pipe 7.
Is connected to the sleeve.

The mounting bracket 24 has a cylindrical shape whose inner diameter is larger than the outer diameter of the pipe 7, and its upper wall 24a is fitted to the pipe 7,
The flexible gas pipe 13 extends from an opening provided in a part of the upper wall 24a.

The engagement fitting 22 connected to the mounting fitting 24 also has an inner diameter of the pipe 7.
Is larger than the outer diameter of the pipe 7 and has a gap between the pipe 7.

On the other hand, a slide fitting 25 having a cylindrical shape and having a flange at a lower end is attached to a lower end portion of the expansion member 21 so as to sandwich an end portion of the expansion member 21 between the expansion member 21 and a fastening ring 26.

The inner diameter of the sliding bracket 25 is slightly larger than the outer diameter of the pipe 7,
There is a slight gap between the pipe 7 and an O-ring fitted in a groove formed in the circumferential direction on the inner peripheral surface of the flange to seal between the slide fitting 25 and the pipe 7. ing.

The slide fitting 25 can slide up and down on the outer peripheral surface of the pipe 7 as the expansion member 21 is deformed.

A communication hole 7a is formed in the pipe 7 at a height between the O-ring 20 and the O-ring 27.

Therefore, the nitrogen gas supplied from the opening of the mounting bracket 24 through the gas pipe 13 enters between the expansion member 21 and the pipe 7 and further passes through the communication hole 7a to pass between the pipe 7 and the plug 8. The gas can pass through the gas passage 8d to the gas pipe 10 to reach the second seal member 12.

The second seal member 12 has substantially the same structure as the first seal member 9, and an expansion member 30 is provided between an upper mounting bracket 31 fitted to the gas pipe 10 and a lower sliding bracket 32. Is provided.

Inside the expansion member 30, a circular hole is formed in the side wall of the gas pipe 10, and the expansion member 30 and the gas pipe 10 are formed through the circular hole.
Is supplied with nitrogen gas.

The rubber sleeve 4 is about 3 mm thick and has a cylindrical rubber layer 4.
On the inner surface of a, two layers of cords 4b and 4c made of a chemical fiber such as polyester are additionally polymerized as a reinforcing layer.

In each of the cords 4b and 4c, the bonding angle or the knitting angle 52 is set so that the expansion and contraction in the radial direction and the length direction are uniform.
The angle of the single fiber in both cords is set to be different from each other by 35 degrees.

As a result, the pressure resistance of the rubber sleeve 4 is improved until the rubber sleeve 4 is not damaged even by a pressure of 60 kg / cm ² .

Since the embodiment shown in FIGS. 2 to 5 is configured as described above, the outer injection tube 2 in which the rubber sleeve 4 is fitted so as to close the injection hole 3 of the outer injection tube 2 is provided.
Is inserted into the vertical hole 1 and the outside of the outer tube 2 is filled with the bentonite mortar liquid 5, and then the parker 6 is inserted into the outer tube 2.
Insert it inside.

Since the injection hole 3 of the outer tube 2 is closed by the rubber sleeve 4, the bentonite mortar 5 is
Do not enter inside.

Then, the gas pipe 10 is positioned at the lowermost injection hole 3, and nitrogen gas is injected through the gas pipe 13 into the sealing members 9, 12.
The expansion members 21 and 30 expand to seal the outer injection tube 2 above and below the group of injection holes 3 to form a closed space.

When the diameter of the expansion members 21 and 30 expands, their lengths are reduced, and the slide fittings 25 and 32 at the lower ends of the seal members 9 and 12 slide slightly upward.

When the cement milk is passed through the pipe 7 in such a state, the cement milk is supplied to the closed space through the through hole 8c of the plug 8, and when the space is filled and further press-fitted, the rubber is injected from the group of injection holes 3 into the rubber. The sleeve 4 is pushed out and oozes into the bentonite mortar liquid 5 and further penetrates into the surrounding ground.

When the cement milk permeated properly into the ground in this way, nitrogen gas was extracted from the sealing members 9 and 12, and the expansion member 2 was removed.
1, the diameter of 30 is reduced, the packer 6 is raised, and the gas pipe 10 is located at the depth position of the second group of injection holes 3 from the next bottom, and the same operation as above is performed to fill the cement milk. To go.

By repeating such operations sequentially, it is possible to form the pillars on the ground while infiltrating the cement milk into the ground.

Since the rubber sleeve 4 has two layers of cords 4b and 4c made of chemical fibers such as polyester polymerized on the inner surface of the rubber layer 4a, the pressure resistance is remarkably improved, and the cement milk from the injection hole 3 is improved. When it is spread by pressure, it is extended substantially equally in each direction.

In another embodiment shown in FIG. 6, the rubber sleeve 40 has an outer rubber layer 40a and two chemical fiber layers 40b, 40c.
And an inner rubber layer 40d. Here, the intermediate chemical fibers 40b and 40c are the same as those in the embodiment shown in FIGS. In this embodiment, both sides of the rubber sleeve 40 are rubber layers, and there is an advantage that the reinforcing layer is not directly exposed to the outside.

In the above-described embodiment, the packer 6 has two plugs 8 and 11. However, the lower portion may be sequentially sealed with only one plug.

As described above, in the present invention, the rubber sleeve is
Since the two-layer cord made of chemical fiber is polymerized on the inner surface of the rubber layer, it is fitted into the outer tube for injection and serves as a valve for sending out cement milk or the like from the inside. The strength of the two layers of cords is remarkably increased with respect to the pressure from different directions because the cords of the two layers are polymerized at different angles of the single fibers. And can be smoothly expanded and contracted in each direction.

Therefore, the ground improvement work can be effectively advanced, and the work can be prevented from being interrupted due to breakage of the rubber sleeve.

[Brief description of the drawings]

FIG. 1 is a perspective view of a conventional rubber sleeve partially cut away, FIG. 2 is a longitudinal sectional view showing an apparatus provided with a rubber sleeve of a ground improvement injection outer tube according to an embodiment of the present invention, and FIG. FIG. 4 is an enlarged longitudinal sectional view of a main part thereof, FIG. 4 is a partially cutaway perspective view showing a rubber sleeve of the embodiment according to the present invention, FIG. 5 is a partial sectional view thereof, and FIG. FIG. 16 is a cross-sectional view corresponding to FIG. 5 in another embodiment according to FIG. 1 ... vertical hole, 2 ... outer injection tube, 3 ... injection hole, 4 ... rubber sleeve, 4a ... rubber layer, 4b, 4c ... cord, 5 ...
Bentonite mortar liquid, 6 Packer, 7 Pipe, 8 Plug, 8a Cylindrical part, 8b Flange part
8c: Through hole, 8d: Gas passage, 9: Seal member, 10:
... gas pipe, 11 ... plug, 12 ... sealing member, 13 ...
... gas pipe, 20 ... O-ring, 21 ... inflatable member, 22 ... engagement fitting, 23 ... fastening ring, 24 ... mounting fitting, 25 ... sliding fitting, 26 ... fastening ring, 27 ... ... O-ring, 30 ... Expansion member, 31 ... Mounting bracket, 32 ... Sliding bracket, 40 ... Rubber sleeve, 40a ... Rubber layer, 40b, 40c ... Cord, 40d ...
... rubber layer.

Claims (1)

(57) [Claims] 1. A rubber sleeve fitted to an outer tube for injecting cement milk or the like into a vertical hole dug in the ground and positioned at an injection hole of the outer tube. A rubber sleeve structure for a ground improvement injection outer pipe, wherein two layers of chemical fiber cords are polymerized on the inner surface of a cylindrical rubber layer at different angles of single fibers.