JP4933845B2 - Injection outer tube device - Google Patents

Description

  The present invention relates to an injection outer tube device used for a chemical solution injection method.

There is a chemical solution injection method as one of the ground improvement methods for the purpose of liquefaction of existing foundation structures and seismic reinforcement of foundation piles in soft ground.
The chemical injection method uses an injection tube installed in the ground, such as by boring, to inject an injection material whose gel time (setting time) can be adjusted within a few seconds to a few hours. It is a construction method that increases water shielding.
In this chemical injection method, chemical injection by horizontal boring is performed in the vicinity of the target structure by constructing vertical boring, oblique boring, or a vertical shaft.

One of the chemical solution injection methods is a double pipe double packer injection method.
Double pipe double packer injection method is, for example, drilling vertically, diagonally or horizontally from the construction yard to the ground, leaving the injection outer pipe at a predetermined depth and position in the target ground. A chemical solution is injected into the ground from an injection inner tube inserted into the tube (for example, see Patent Document 1).

By the way, the drilling pipe used for the drilling is constituted by a double pipe of a polyethylene drilling outer pipe and a flexible drilling rod. A cutting bit is provided at the tip of the drilling rod. After drilling to a predetermined position, all the drilling rods are withdrawn, and the outer pipe is inserted into the predetermined position through the outer drilling pipe. Build in. After completion of the injection outer pipe erection, muddy water is sent into the outer drilling pipe at the time of pulling out the outer drilling pipe to reduce the internal resistance.
And cement bentonite is inject | poured from an injection | pouring inner pipe, and the injection | pouring operation | work of a chemical | medical solution is performed finally.
Japanese Patent Laid-Open No. 9-143777

However, at the time of pulling out the outer tube, there is a case where a so-called joint rise phenomenon occurs in which the outer tube is pulled out together with the outer tube. Actually, the actual situation is that the co-up of about 100 mm to 1000 mm occurs frequently.
For this reason, in the field, the injection outer tube is manually returned to a predetermined position, etc., but in the case of loose sand ground, the hole wall may collapse, and the injection outer tube may not be pushed back. is there. In that case, it becomes a re-drilling hole, and an extra cost is often required.
As described above, in the chemical solution injection construction and the similar construction, an effective method for preventing the joint outer pipe from rising together has not been established.

  An object of the present invention is to reliably prevent the injection outer tube from being pulled out.

In order to solve the above-mentioned problems, the invention according to claim 1 is an injection outer tube that is inserted into the ground and injects an injection material . The front end portion is provided with a wedge member having a plurality of wedge portions capable of projecting in the outer peripheral direction.

Furthermore, the invention described in claim 1 includes a cap that covers the wedge portion of the wedge member from the distal end portion side and restrains the protruding operation in the outer circumferential direction.

The invention according to claim 2 is the injection outer tube device according to claim 1 , wherein the wedge portion is formed by a leaf spring and is always urged in the protruding operation direction .

The invention according to claim 3 is the injection outer tube device according to claim 1 or 2 , wherein the cap functions as a guide when the injection outer tube is inserted into the ground, and the outer injection device It is characterized in that it is detached from the tip of the injection outer tube by injection of the injection material into the tube.

According to the present invention, the wedge portion of the wedge member in which the cap is detached from the tip portion by injection of the injection material into the injection outer tube inserted into the ground , and the inner cylinder portion is inserted into the injection outer tube tip portion is provided. By projecting in the outer peripheral direction, it is possible to reliably prevent the injection outer tube from being pulled out.
As described above, the device for preventing the extraction of the injection outer tube can be manufactured with a simple structure and at a low cost without requiring a complicated mechanism or structure such as an electric type.
Further, the wedge member can be easily attached to the tip portion of the existing injection outer tube.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a configuration of an embodiment to which the present invention is applied. 1 is an outer injection tube, 11 is an injection hole, 12 is a check valve rubber sleeve, 2 is a wedge member, 21 is an inner cylinder, and 22 is A wedge part, 23 is a partition part, 24 is a check valve, 3 is a cap, 4 is an injection inner pipe, 41 is an ejection hole, 42 and 43 are packer rubbers (packer part), and 44 is an ejection hole.

As shown in the figure, the injection outer tube 1 is made of vinyl chloride, and includes an injection hole 11 and a check valve rubber sleeve 12, and a wedge member 2 and a cap 3 at the tip.
The wedge member 2 integrally has a plurality of wedge portions 22 that can be protruded in the outer peripheral direction at the distal end portion of the inner cylinder portion 21 inserted into the distal end portion of the injection outer tube 1. For example, the inner cylinder portion 21 is made of metal, and in particular, the wedge portion 22 is formed by a leaf spring and is always urged in the protruding operation direction.

And the wedge member 2 is provided with the partition part 23 which partitions off the inside of the inner cylinder part 21 back and forth. A central portion of the partition wall 23 is provided with a check valve 24 that allows the flow of the injection material from the injection inner pipe 4 side but prevents the flow on the opposite side.
The cap 3 covers the wedge portion 22 of the wedge member 2 from the distal end side to prevent its protruding operation, and also functions as a guide when the outer injection tube 1 is built into the ground. The cap 3 is made of, for example, metal or resin.

The injection inner tube 4 inserted into the above injection outer tube 1 has an injection pressure of the injection material at the time of supply of the injection material at a position before and after the injection hole 41 of the injection material such as cement bentonite or chemical liquid. Thus, there are provided packer rubbers 42 and 43 constituting a packer part that expands and deforms like a balloon.
The injection tube 4 is formed with an ejection hole 44 at the tip end portion of the front packer rubber 42.

Next, FIG. 2 shows a state in which the wedge member 2 protrudes, and the injection outer tube 1 is installed at a predetermined position in the ground, and the injection inner tube 4 is inserted into the injection outer tube 1. To do. In this state, the high pressure water is supplied to the injection inner tube 4 to expand only the front packer rubber 42 and the high pressure water is ejected from the ejection hole 44 at the tip portion, so that the cap 3 is moved forward as shown in the figure. Let go.
Thereby, the wedge part 22 of the wedge member 2 protrudes in the outer peripheral direction by the bias of the leaf spring and penetrates into the natural ground. Therefore, at the time of pulling out a drilling outer tube (not shown), the injection outer tube 1 is reliably prevented from being pulled out, and the injection outer tube 1 is fixed at a predetermined position.

As described above, the device for preventing the extraction of the injection outer tube can be manufactured with a simple structure and at a low cost without requiring a complicated mechanism or structure such as an electric type.
Moreover, the above wedge member 2 can be easily attached to the front-end | tip part of the existing injection | pouring outer tube | pipe.

As described above, the check valve 24 is built in the central portion of the partition wall portion 23 of the inner cylinder portion 21 of the wedge member 2 so that the injected water does not flow back from the cap 3 side and the cap 3 is not mounted again.
Here, the cap 3 may be fitted so that it can be easily detached even by manual work. In addition, since the injected water does not flow back by the check valve 24, if the supply of water is continued, the internal pressure of the cap 3 increases and the cap 3 is easily detached.
The length and angle of the wedge portion 22 of the wedge member 2 can be arbitrarily set as long as they can penetrate into the natural ground. Further, the number of wedge portions 22 is restricted by the inner diameter of the outer injection tube 1, but any number of wedge portions 22 may be provided radially as much as possible.

FIG. 3 shows an example of the shape of the wedge member 2 during the protrusion operation.
That is, as shown in FIG. 3A, two rod-like wedge portions 22 positioned on the diametrical extension of the inner cylinder portion 21, and as shown in FIG. 3B, the inner cylinder portion 21 is orthogonal. Four rod-shaped wedge portions 22 positioned on the diametrical extension, as shown in FIG. 3C, eight rod-shaped wedge portions 22 positioned on the diametrical extension of the inner cylinder portion 21 by 45 degrees, As shown in FIG. 3D, any of the four pyramidal wedge portions 22 positioned on the diametrical extension of the inner cylinder portion 21 may be used. In particular, the type shown in FIG. 3D is obtained by increasing the rigidity of the wedge member 2 in order to prevent the wedge member 2 from being broken during penetration.

  In addition to the above embodiments, it is needless to say that specific detailed structures and the like can be appropriately changed. For example, the structure, shape, and material of the wedge member can be arbitrarily selected.

The structure of one Embodiment to which this invention is applied is shown, and it is the principal part fracture | rupture side view which showed the time of insertion of the injection | pouring inner tube | pipe to the injection | pouring outer tube | pipe. It is the principal part fracture | rupture side view which showed the time of protrusion operation | movement of the wedge member of FIG. It is a front view (ad) which shows the example of a shape of the wedge member at the time of the protrusion action | operation of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Injection outer pipe | tube 11 Injection hole 12 Check valve rubber sleeve 2 Wedge member 21 Inner cylinder part 22 Wedge part 23 Partition part 24 Check valve 3 Cap 4 Injection inner pipe 41 Injection hole 42 * 43 Packer part 44 Injection hole

Claims (3)

In the outer injection tube to be injected into the ground and injected with the injection material,
A wedge member having a plurality of wedge portions capable of projecting in the outer peripheral direction is provided at the distal end portion of the inner cylinder portion inserted into the distal end portion of the injection outer tube ,
The injection outer tube device according to claim 1, further comprising a cap that covers the wedge portion of the wedge member from the tip portion side and restrains the protruding operation in the outer circumferential direction . The injection outer tube device according to claim 1, wherein the wedge portion is formed of a leaf spring and is always urged in the protruding operation direction . The cap functions as a guide when the injection outer tube is inserted into the ground, and is detached from a distal end portion of the injection outer tube by injection of an injection material into the injection outer tube. 3. The outer injection tube device according to 1 or 2.

Images