JPH09221739A - Multiple pipe and injection method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a rubber layer from being rubbed with an excavated hole surface and resultantly damaged by providing a rubber layer for the formation of a packer which prevents the flow out of a chemical solution and laying out a rod material in the peripheral direction of a pipe with a proper spacing and covering the outer peripheral surface of the rubber layer. SOLUTION: A packer-loaded multiple pipe 1 is provided with a rubber layer 2 which prevents the flow out of a chemical solution. A plurality of spring steel-made rod materials 3 are axially provided on the outer periphery surface of the rubber layer 2, which is the packer portion, in the peripheral direction of the pipe with a proper spacing. The rod materials 3 cover the outer peripheral surface of the rubber layer 2 and are fixed with a reinforcing layer 4 which is not expanded with a pressurizing gas where a boring machine is used for boring a hole into which the multiple pipe 1 is inserted. During this work, the rubber layer 2 is protected with the rod materials 3 so that they may not be damaged even when they are rubbed with the hole wall. Then, the multiple pipe 1 is set up at a specified position, thereby expanding the rubber layer 2. A chemical solution is injected in this state. The rod materials 3, if the pressure is eliminated, will be returned unaided. This construction makes it possible to use the multiple pipe 1 repeatedly in an excellent state for a long period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiple pipe having a built-in packer for preventing a chemical solution from flowing out from the perforation when the ground is perforated and a chemical solution is injected from the hole to improve the ground.

[0002]

2. Description of the Related Art In the case of tunnel excavation or the like, in order to improve the soft ground, a small boring machine is used to drill the ground, multiple pipes are inserted into the holes, and a chemical solution is injected through the pipes to soft ground. It has been widely practiced to improve the above with a chemical solution.

At this time, in order to allow the chemical solution to permeate a wide area of the soft ground, the chemical solution is injected at a considerably high pressure, but the chemical solution does not rise (backflow) in the drill hole and flow out to the outside. The packer is inflated and brought into close contact with the wall of the hole, blocking the backflowing drug solution.

Most of the packers of this type are disclosed in JP-A-6-17.
As seen in Japanese Patent No. 3243 and Japanese Patent Application No. 6-170649, a rubber layer that expands with compressed air that is a pressurized gas is provided in a part of a multiple pipe for injecting a chemical solution, and a multiple pipe is formed after piercing the ground. The rubber layer serving as a packer is contracted when it is inserted into the perforation, and the rubber layer is expanded and sealed when the liquid medicine is injected through the multiple pipes.

[0005]

However, in the case of the conventional packer, the rubber layer (rubber pipe) that expands by compressed air and performs a sealing (or blocking) action as the packer is exposed as it is, and the rubber layer is not exposed. There is nothing to protect. Therefore, when the pucker is inserted into the perforation, the pucker portion, which is a rubber layer, is liable to be damaged by rubbing against the excavation hole wall, and sometimes worn out due to friction with the hole wall, which makes it unusable as a pucker.

The present invention has been proposed in view of the problems of the prior art as described above, and protects the rubber layer serving as the packer, and when the packer is inserted into the excavation hole, the packer portion serving as the rubber layer is It is an object of the present invention to provide a multiple pipe which is prevented from being damaged by rubbing against a borehole wall and can be repeatedly used for a long period of time.

[0007]

The multiple pipe of the present invention is a multiple pipe for inserting a chemical solution for improving the ground, which is inserted into an excavation hole drilled in the ground, wherein the multiple pipe is pressurized. A rubber layer for forming a packer that expands by gas and adheres closely to the hole wall to prevent the outflow of the chemical liquid is provided, and the outer peripheral surface of the rubber layer is made of spring steel and extends in the axial direction of the tube. The existing rods are arranged at appropriate intervals in the circumferential direction of the pipe and in such a manner as to cover the outer peripheral surface of the rubber layer.

If the chemical injection method is applied using the multiple pipe of the present invention having the above-mentioned structure, the rubber is used when the multiple pipe is inserted into the excavation hole when the chemical is injected to improve the ground. The layer does not contact the borehole wall because its surface is protected by rods. Therefore, it is possible to prevent the rubber layer from being rubbed against the borehole wall and damaged.

When a compressed pipe is supplied after inserting a multi-pipe containing a packer into the drill hole, the rubber layer of the packer expands, the outer peripheral portion of the rubber layer adheres to the wall of the drill hole and rises from below. Seal or shut off. At this time, since the bar made of spring steel has elasticity, it deforms so as to spread (expand) outward in the radial direction. Then, the elasticity of spring steel causes the bar to shrink inward in the radial direction when compressed air is removed, and restores to its original state by itself.

As described above, according to the present invention, since the rubber layer of the packer is not damaged, the multiple pipe can be repeatedly used. When injecting the drug solution, it is possible to reliably seal or block the drug solution rising from below.

Here, it is preferable that the rod member is fixed by a portion other than the packer portion of the multiple pipe, that is, a reinforcing layer that does not substantially expand by the pressurized gas. Further, in the multiple pipe of the present invention, the bar made of spring steel is exposed to the outside in the packer together with the rubber layer.

In the practice of the present invention, the bar member made of spring steel and the packer part made of a rubber layer may be provided in a plurality of stages at intervals in the axial direction of the multiple pipe, or You may provide only one place in the axial direction of a multiple pipe. In the case where a plurality of stages are provided, it is preferable that the two packer portions that are continuous in the axial direction of the multiple pipe are arranged such that the circumferential positions of the bar made of spring steel are displaced from each other. If a plurality of stages of packers are provided and the circumferential positions of the bars of the two packers that are continuous in the axial direction of the multiple pipe are mutually displaced, the so-called "labyrinth seal" action blocks the backflow of the chemical liquid. Because.

Further, the multiple pipe of the present invention is a multiple pipe which is inserted into an excavation hole drilled in the ground to inject a chemical solution for improving the ground, and the multiple pipe is expanded by a pressurized gas. A rubber layer for forming a packer that adheres to the hole wall to prevent the chemical liquid from flowing out is provided, and the outer peripheral surface of the rubber layer is
A plurality of strip-shaped protective plates that are constantly urged inward by a spring force to cover a part of the outer peripheral surface of the rubber layer are arranged at appropriate intervals in the circumferential direction of the multiple pipe.

Here, the protection plate is rotatable about a rotation shaft, and both ends of the rotation shaft do not substantially expand due to a portion other than the packer portion of the multiple pipe, that is, the pressurized gas. It is preferably pivotally supported by a reinforcing layer.

According to the present invention having such a configuration,
Since a part of the outer peripheral surface of the rubber layer is covered with a belt-shaped protective plate, the multiple pipes can be inserted into the excavation hole without coming into contact with the excavation hole wall. Therefore, the rubber layer of the packer is not damaged, and the multiple pipe can be repeatedly used.

When compressed air is supplied after inserting a multiple pipe containing a packer into the excavation hole, the rubber layer of the packer part expands, its outer peripheral portion adheres to the excavation hole wall and rises from below. Seal or shut off. At this time, since the protective plate rotates in the direction in which it expands radially outward, it does not hinder the expansion of the packer. Since the protective plate is constantly urged inward by the spring force, if compressed air is removed, the protective plate contracts inward in the radial direction and restores the original state.

In practicing the present invention, it is preferable that a plurality of pucker portions formed of the protective plate and the rubber layer are provided at intervals in the axial direction of the multiple pipe. In this case, the two packing parts that are continuous in the axial direction of the multiple pipe are
It is preferable that the protective plates are arranged so that their circumferential positions are displaced from each other. Although there is a part that is not blocked by the packer in the rotating part of the protective plate, a plurality of stages of packing parts are provided, and the protective plate of (the rotating part of) the protective plate of the two packing parts that are continuous in the axial direction of the multiple pipe This is because if the positions are displaced from each other, the backflow of the chemical liquid is blocked by the action equivalent to the so-called "labyrinth seal".

The injection method of the present invention using the above-mentioned multiple pipe is provided in the multiple pipe by an excavation process of drilling a drill hole in the ground, a multiple pipe insertion process of inserting the multiple pipe into the drilled hole. A gas is supplied to the packed packer from the ground to expand the packer, and a packer expanding step of liquid-tightly blocking the area above the packer and the area below the packer in the drill hole and a chemical solution for improving the ground are provided. And a pucker contraction step of contracting the pucker by discharging the gas supplied to the pucker from the pucker when a predetermined time has elapsed after the pour-in solution, A rubber layer for forming a packer that expands by the pressurized gas and adheres closely to the hole wall to prevent the outflow of the chemical liquid is provided, and the outer peripheral surface of the rubber layer is made of spring steel and is in the axial direction of the tube. The rod extending to the circumference of the pipe In a manner covering the outer peripheral surface of and at a suitable distance the rubber layer, it is characterized in that it is arranged.

Alternatively, the pouring method of the present invention using the above-mentioned multiple pipe includes an excavation step of boring an excavation hole in the ground, and a multi-pipe insertion step of inserting the multi-pipe into the perforated excavation hole,
Gas is supplied from the ground to the packer provided in the multiple pipes to expand the packer, and the packer expansion process that liquid-tightly separates the area above the packer and the area below the packer in the drill hole is improved, and the ground is improved. And a pucker contraction step of contracting the pucker by discharging the gas supplied to the pucker from inside the pucker when a predetermined time has elapsed after the pour-in solution, Multiple tubes
A rubber layer for forming a packer that expands by the pressurized gas and adheres to the hole wall to prevent the chemical liquid from flowing out is provided, and the outer peripheral surface of the rubber layer is constantly urged inward by a spring force. A plurality of strip-shaped protective plates that cover a part of the outer peripheral surface of the rubber layer are arranged at appropriate intervals in the circumferential direction of the multiple pipe.

The use of such an injection method is very convenient because expansion and contraction of the packer can be repeated many times.

Here, in the injection method of the present invention using the above-mentioned multi-tube, the gas supplied for expanding the packer is selected such that the restoring speed at which the expanded packer contracts increases. Is preferred. If such a gas is selected, not only the time spent in the packer shrinking step is shortened, but also the speed that follows the change of the ground over time becomes faster, so the chemical solution injection method is applied to the easily deformable ground. This is because there is no fear of adversely affecting the surroundings when constructing. In addition, as the "gas that increases the restoration speed at which the expanded packer contracts", for example, nitrogen gas (N ₂ gas) is preferable.

Further, in the present invention, in the packer, the connecting portion with the multiple pipe is made of rubber containing a core material, and the parts other than the connecting portion are made of rubber containing no core material. Is preferred. When the packer expands, it comes into contact with the inner peripheral surface of the drill hole and liquid-tightly separates the area above the packer and the area below the packer, so that it follows the shape of the inner surface of the drill hole. It must be flexible and must have a certain strength or more. On the other hand, in order to prevent leakage from the connecting portion between the packer and the multiple pipe, the connecting portion must be made of a material that has sufficient strength and is not easily deformed, that is, a material that lacks flexibility. . Here, the rubber containing the core material has improved strength but small flexibility. Therefore,
If the connecting portion between the packer and the multiple pipe is made of rubber containing a core material, and the packers other than the connecting portion are made of rubber containing no core material, the above-mentioned requirements can be satisfied. .

As a rubber suitable for the packer of the present invention, that is, a rubber having a flexibility to follow the shape of the inner peripheral surface of the excavation hole and having a strength not less than a predetermined value. Are, for example, natural rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroprene rubber, nitrile butadiene rubber, ethylene propylene rubber, butyl rubber, hypalon, acrylic rubber, urethane rubber, silicone rubber, fluorine rubber, and polysulfide rubber.
Natural rubber and urethane rubber are particularly preferable.

[0024]

1 to 4 show a first embodiment of the present invention. The multiple pipe 1 is provided with a rubber layer 2 that expands by compressed air that is a pressurized gas and adheres closely to the wall of the drill hole to prevent the outflow of the chemical liquid. The outer peripheral surface of the rubber layer 2 serving as a packer is made of spring steel. A plurality of the rods 3 are provided in the axial direction of the pipe at appropriate intervals in the circumferential direction of the pipe, eight in the illustrated example. The rod 3 covers the outer peripheral surface of the rubber layer 2 and is fixed by a reinforcing layer 4 (a portion of the multiple pipe other than the packer portion) that does not substantially expand by a pressurized gas (for example, nitrogen gas: the same hereinafter).

The rubber layer 2 is made of urethane rubber, for example. Although not clearly shown, a core material is embedded inside the rubber layer 2 serving as a packer at the boundary with the multi-layer pipe 1, but not at the boundary. No core material is buried.

The reinforcing layer 4 preferably comprises a synthetic fiber layer and a steel wire layer. In the example shown in the figure, three parts are provided as packers. Further, the bar members 3 made of spring steel of the adjacent packers are arranged so as to be displaced from each other in the circumferential direction of the pipe.

Although not shown, the rubber layer 2
Further inside is a synthetic resin hose for supplying a chemical solution.

In order to improve the ground by injecting a chemical solution, first, the ground is perforated by a small boring machine. Next, the above-mentioned multiple pipe 1 is inserted into the excavation hole. At this time, since the surface of the rubber layer 2 is protected by the rod 3, the excavation hole does not come into contact with the excavation hole wall and the excavation hole is excavated. There is no inconvenience such as rubbing against the hole wall and scratching the rubber layer 2. 1 and 2 show a state in which the multiple pipe 1 is inserted.

After the multi-pipe 1 is installed at a predetermined position in the excavation hole, nitrogen gas (N ₂ gas) which is a pressurized gas is supplied to expand the rubber layer 2 of the packer. At that time, as shown in FIGS. 3 and 4, the rod 3 also spreads outward, but since the rod 3 is made of spring steel,
If the pressurized gas is removed, the original state shown in FIGS. 1 and 2 is restored by itself.

The rubber layer 2 of the packer portion is expanded and brought into close contact with the wall of the excavation hole, thereby sealing or blocking. In this case, the chemical solution may slightly leak from the R portion where the rod 3 shown in FIG. 4 is provided. Therefore, as described above, the bar members 3 of the adjacent packer portions are arranged so as to be displaced from each other in the circumferential direction of the pipe. As a result, the leakage of the chemical solution from the R portion is completely blocked (blocked).

After operating the packer in the above-described manner, the chemical solution is injected through the multiple pipe 1 to improve the ground. When the injection of the chemical liquid through the excavation hole is completed, the pressurized gas is discharged from the packer to contract the rubber layer 2, and the multiple pipe 1 is pulled out from the excavation hole to be used for supplying the chemical liquid through the next excavation hole.

It should be noted that the pucker portion provided with the rod may be provided at only one place, but if it is provided at a plurality of places (three places) as shown in the figure, the sealing or blocking will be more reliable.

A second embodiment of the present invention is shown in FIGS. 5 to 8. The multi-layer pipe 10 is a rubber layer which expands by compressed air which is a pressurized gas and adheres closely to the wall of the borehole to prevent the chemical liquid from flowing out. On the outer peripheral surface of the rubber layer 11 serving as a packer portion, a belt-shaped protective plate 12 that is constantly urged inward by a spring force to cover a part of the rubber layer is provided in the circumferential direction of the pipe. A plurality of sheets, four in the illustrated example, are provided. The protective plate 12 is made of a metal plate, and is attached to the pipe by a rod member 13. A synthetic resin hose 14 for passing a chemical liquid is provided on the inner layer of the rubber layer.

5 and 6 show the state of the protective plate 12 when the multiple pipe 10 is inserted into the drill hole, and the surface of the rubber layer 11 is protected by the protective plate 12 so that it does not come into contact with the wall of the drill hole. In addition, the rubber layer 11 is not scratched by rubbing against the wall of the drilled hole.

By supplying the pressurized gas, the rubber layer 11 of the packer portion expands as shown in FIGS. 7 and 8, and the rubber layer 11 is brought into close contact with the wall of the drill hole to seal or block it. Also in the case of this embodiment, since the chemical liquid may leak from the mounting portion R of the protective plate 12 to some extent, the protective plates 12 of the adjacent packers are arranged so as to be offset from each other in the circumferential direction of the pipe. As a result, the leakage of the chemical solution from the R section is completely prevented.

It should be noted that the packer portion provided with the protective plate may be provided at only one place, but as shown in the drawing, a plurality of places (3 places) are provided.
If it is provided, the sealing or blocking will be more reliable.

[0037]

According to the multiple pipe and injection method of the present invention,
The surface of the rubber layer of the packer is protected by rods or plates, so when pouring a chemical solution to improve the ground and inserting multiple pipes into the excavation hole, the rubber layer rubs against the excavation hole wall. It can be repeatedly used for a long time in good condition without being damaged.

Even if a bar material or a plate material is provided on the surface of the rubber layer of the packer portion, the bar material or the plate material functions as a spring, so that supplying pressurized gas does not hinder the packing of the packer portion. The rubber layer expands and adheres well to the borehole wall and seals or blocks well. At this time, the bar or plate spreads outward, but if the pressurized gas is removed, it will return to its original state by itself and can be used as it is.

Further, by providing a plurality of packer portions provided with rods or plates and arranging the rods or plates of the adjacent packers so as to be displaced from each other in the circumferential direction of the pipe,
More reliable sealing or interruption can be performed.

Further, in the pouring method of the present invention, if a gas that increases the speed at which the expanded pucker shrinks is used, not only the time spent in the pucker shrinking step is shortened but Since the speed of following such changes becomes faster, there is no risk of adversely affecting the surroundings when the chemical injection method is applied to the easily deformable ground,
It is suitable.

[Brief description of drawings]

FIG. 1 is a front view showing a state in which a packer of a multiple pipe is contracted in a first embodiment.

FIG. 2 is an enlarged cross-sectional view of the packer portion of FIG.

3 is a front view showing an expanded state of a packer in the multiple pipe of FIG. 1. FIG.

FIG. 4 is an enlarged sectional view of the packer portion of FIG.

FIG. 5 is a front view showing a state in which the packer is contracted in the second embodiment.

6 is an enlarged cross-sectional view of the packer portion of FIG.

7 is a front view showing the expanded state of the packer in the multiple pipe of FIG.

8 is an enlarged cross-sectional view of the packer portion of FIG.

[Explanation of symbols]

 1 ... Packer with multiple tubes 2 ... Rubber layer 3 ... Bar material made of spring steel 4 ... Reinforcing layer 10 ... Packer with multiple tubes 11 ... Rubber layer 12 ... Protective plate 13 ... Bar material 14 ... Synthetic resin hose

Claims (9)

[Claims] 1. A multi-tube inserted into an excavated hole in the ground to inject a chemical solution for improving the ground, the multi-tube being expanded by a pressurized gas and closely contacting with a hole wall. A rubber layer for constituting a packer for preventing the chemical liquid from flowing out, and a bar member made of spring steel and extending in the axial direction of the tube is provided on the outer peripheral surface of the rubber layer in the circumferential direction of the tube. A multiple pipe, wherein the multiple pipes are arranged at appropriate intervals and in such a manner as to cover the outer peripheral surface of the rubber layer. 2. The multiple pipe according to claim 1, wherein a plurality of stages of the packer portion made of the spring steel and the rubber layer are provided at intervals in the axial direction of the multiple pipe. 3. The multiple pipe according to claim 2, wherein the two packer portions which are continuous in the axial direction of the multiple pipe are arranged such that the circumferential positions of the rods made of spring steel are displaced from each other. 4. A multi-tube which is inserted into an excavation hole drilled in the ground and injects a chemical solution for improving the ground, wherein the multi-tube is expanded by a pressurized gas and adheres closely to the hole wall. A rubber layer for forming a packer for preventing the chemical liquid from flowing out, and the outer peripheral surface of the rubber layer is a belt-like member that is constantly urged inward by a spring force to cover a part of the outer peripheral surface of the rubber layer. A plurality of protective plates are provided at appropriate intervals in the circumferential direction of the multiple tube. 5. The multiple pipe according to claim 4, wherein the packer portion including the protective plate and the rubber layer is provided in a plurality of stages at intervals in the axial direction of the multiple pipe. 6. The multiple pipe according to claim 5, wherein the two packer portions which are continuous in the axial direction of the multiple pipe are arranged such that the circumferential positions of the protective plate are displaced from each other. 7. A drilling step of drilling a drill hole in the ground, a multiple pipe inserting step of inserting a multiple pipe into the drilled hole, and a gas is supplied from the ground to a packer provided in the multiple pipe. The pucker is expanded to make the pucker expand and the region below the pucker of the drill hole is liquid-tightly closed, and the pucker expansion process for injecting a chemical liquid to improve the ground and a predetermined time after the chemical liquid injection When the time has elapsed, the gas supplied to the packer is discharged from the inside of the packer to shrink the packer, and the multi-tube expands by the pressurized gas to adhere to the hole wall. Thus, a rubber layer for forming a packer for preventing the outflow of the chemical liquid is provided, and a rod member made of spring steel and extending in the axial direction of the pipe is provided on the outer peripheral surface of the rubber layer in the circumferential direction of the pipe. At an appropriate distance from the outer circumference of the rubber layer The injection method using the multiple pipe according to any one of claims 1 to 3, wherein the injection method is arranged so as to cover the surface. 8. A drilling step of drilling a drill hole in the ground, a multiple pipe inserting step of inserting a multiple pipe into the drilled drill hole, and supplying gas from the ground to a packer provided in the multiple pipe. The pucker is expanded to make the pucker expand and the region below the pucker of the drill hole is liquid-tightly closed, and the pucker expansion process for injecting a chemical liquid to improve the ground and a predetermined time after the chemical liquid injection When the time has elapsed, the gas supplied to the packer is discharged from the inside of the packer to shrink the packer, and the multi-tube expands by the pressurized gas to adhere to the hole wall. Thus, a rubber layer for constituting a packer for preventing the outflow of the chemical liquid is provided, and the outer peripheral surface of the rubber layer is constantly urged inward by a spring force to cover a part of the outer peripheral surface of the rubber layer. A strip-shaped protection plate is provided between The injection method using the multiple pipe according to any one of claims 4 to 6, wherein a plurality of sheets are arranged at intervals. 9. The packing of the packer is made of rubber containing a core material at a connecting portion to the multi-layer pipe, and is made of rubber not containing a core material at portions other than the connecting portion. The injection method according to any one of 7 and 8.