JP2697779B2 - Freezing method and equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for drilling a borehole in the ground to be frozen, inserting a tube into the borehole,
The present invention relates to a freezing method for injecting a cryogen through the tube and an apparatus suitably used for the method.

[0002]

2. Description of the Related Art The freezing method is implemented for the purpose of strengthening the ground, stopping water, and the like, and is often used for temporary structures.

An outline of the freezing method will be described with reference to FIG. A boring hole 1 is excavated in the ground G to be frozen, and a triple pipe 2 is inserted into the hole 1. The triple tube 2 has three sections 3,
A cryoprotectant (brine or the like) C such as an aqueous calcium chloride solution is injected from a section 5 inside the tube 2 in the radial direction.

[0005] In FIG. 5, reference numeral A denotes an area to be frozen in the ground G (freezing area or frozen area).
Reference symbol B indicates a non-freezing range (non-freezing range or non-freezing region). Then, the freezing range A and the non-freezing range B
Is indicated by reference symbol S.
At this boundary level S, a section 3 radially outside the pipe 2
Is closed, and a space between the surface and the ground surface GS (a portion corresponding to the non-frozen portion B) is filled with a heat insulating material H such as styrene foam.

At the time of construction, if the triple pipe 2 is inserted into the boring hole 1 and the freezing agent C is injected from the radially inner section 5, the freezing range A of the ground G immediately freezes. on the other hand,
Since the heat insulating material H is filled in the section 3 on the radially outer side of the pipe 2, the non-freezing range B in the ground G does not freeze.

[0006]

Here, when the reaching depth to the freezing range A is relatively deep and the triple tube 2 needs to be lengthened, it has conventionally been necessary to add the triple tube.

[0007] However, the work of replenishing the triple pipe requires a great deal of labor and cost, and has caused a rise in the overall construction cost of the freezing method.

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above-mentioned problems of the prior art, and has as its object to provide a freezing method and apparatus which can save the cost and labor required for adding pipes for a chemical solution. I have.

[0009]

The freezing method according to the present invention is characterized in that a boring hole is excavated in the ground to be frozen, a tube is inserted into the boring hole, and a cryogen is injected through the tube. The tube is a double tube only in the non-freezing range and is made of a metal tube with a small diameter without a seam, and when the metal tube is inserted into the bore hole, the metal tube on the outer side is used. A step of coating the heat insulating material; and a step of peeling off the heat insulating material coated on the metal tube when the metal tube is pulled out from the inside of the boring hole.

[0010] The apparatus of the present invention for carrying out this freezing method comprises a seamless metal tube having a small diameter, a take-up reel for winding and holding the metal tube, and a device for inserting the metal tube into a boring hole. Includes means for coating the outer peripheral portion of the metal tube with a heat insulating material, and means for peeling off the heat insulating material coated on the metal tube when the metal tube is pulled out from the boring hole.

Here, the so-called "coiled tube" is desirable as the seamless metal tube having a small diameter.

As means for coating or peeling off the heat insulating material, all known techniques can be applied.

[0013]

According to the present invention having the above-described structure,
Since the freezing agent is injected through a seamless small-diameter metal tube, that is, a coiled tube, even if the freezing range exists deep underground (deep region),
There is no need for a pipe replenishing process as in the prior art. Here, the coiled tube is used in petroleum mining work and has durability that can be used under high temperature and high pressure, and thus has sufficient strength required for the freezing method.

However, the coiled tube has no heat insulating or heat retaining structure on its outer peripheral surface. Therefore, if the cryogen is simply allowed to flow through the coiled tube, the non-freezing range may be frozen. On the other hand, according to the present invention, when a coiled tube having a length corresponding to the freezing range is inserted when the coiled tube is inserted into the boring hole, the coiled tube is moved to a non-freezing range higher than that. The outer peripheral surface of the corresponding coiled tube is covered with a heat insulating material. Therefore, even if a cryoprotectant is injected, the non-freezing range does not freeze.

[0015] On the other hand, the coiled tube is wound up by the reel after the freezing operation is completed. However, when the coiled tube is covered with the heat insulating material, it becomes bulky when wound around the reel. For this reason, in the present invention, a means for peeling off the coated heat insulating material when wound around a reel is provided. Moreover, by peeling off the heat insulating material, the coiled tube can be reused for other uses other than the freezing method.

As means for coating or peeling off the heat insulating material, any known technique may be applied as it is, so that complicated equipment is not required for carrying out the present invention.

[0017]

An embodiment of the present invention will be described below with reference to FIGS. The same members as those shown in FIG. 5 are denoted by the same reference numerals, and redundant description will be omitted.

In FIG. 1, a boring hole 1 is drilled in the soft ground G to be subjected to the freezing method, and a coiled tube 10 is inserted into the boring hole 1.
The coiled tube 10 includes an outer tube 10-1 and an inner tube 10
-2, and is housed in a state wound on a take-up reel 12 installed on the ground, and connected to a cryogen supply source (not shown).

Here, on the ground, a heat insulating material coating means 14 for coating the coiled tube 10 with the heat insulating material H is provided. Then, as is apparent from FIG.
The coiled tube 10 below and above the boundary level S (corresponding to the non-freezing range B) is covered with a heat insulating material H.

The covering means 14 is schematically shown in FIG. In FIG. 2, the covering means 14 is a coiled tube 1
A plurality (three in FIG. 3) arranged at equal intervals around 0
Insulation nozzles 16 are included. The spray nozzles 16 spray the heat insulating material H while rotating in the direction of arrow R with respect to the coiled tube 10 to form a layer of the heat insulating material H on the surface of the coiled tube 10 ( Coating). The thickness of the coating layer of the heat insulating material H is adjusted by a control unit (not shown) so that the diameter of the covered coiled tube 1 becomes equal to the diameter of the boring hole 1.

In carrying out the freezing method, first, a boring hole 1 is drilled by a not-shown excavating means. Next, the take-up reel 1 installed near the boring hole 1
2 in the reel pull-out direction (in the case of FIG.
CW), the coiled tube 10 is pulled out, and inserted into the boring hole 1. Here, the pulled-out coiled tube 10 is inserted into the boring hole 1 through the coating means 14, but when the portion corresponding to the freezing range A passes through the coating means 14, the heat insulating material H is coated. Absent. The coating of the heat insulating material H on the coiled tube 10 is adjusted by a control unit (not shown) so that the portion corresponding to the non-freezing area B passes through the coating unit 14.

If the inner tube 10-2, which is the uncoated portion of the coiled tube 10, reaches the freezing range,
The cryogen is injected from a cryogen supply unit (not shown) connected to the reel 12. As a result, the non-freezing range B where the coiled tube 10 covered with the heat insulating material H exists does not freeze, but the ground where the uncovered portion (the portion corresponding to the freezing range A) exists freezes immediately. . Here, since the coiled tube 10 is a seamless and extremely long metal tube, even if the freezing range A exists in a relatively deep region, the pipe refilling operation as in the related art is not necessary. .

After completion of the freezing operation, the coiled tube 10 is wound around the reel 12 (rotated clockwise CW) and accommodated. At this time, it is preferable to remove the coating layer of the heat insulating material H. This is because the presence of the coating layer causes the coiled tube 10 to be bulky. Therefore, as shown in FIG. 3, the covered coiled tube 10 pulled out from the boring hole 1 is wound on a reel 12 after passing through a means 20 for stripping the heat insulating material.

The outline of the stripping means 20 is shown in FIG. In FIG. 4, the stripping means 20 includes a relatively large-diameter opening 22, a relatively small-diameter opening 24, and a plurality of spirally arranged (3 in FIG. 4) regions between the two openings.
) Cutting blades 26. Here, the difference between the diameters of the openings 22 and 24 corresponds to the thickness of the coating layer made of the heat insulating material H.

Coiled tube 1 covered with heat insulating material H
When 0 passes through the stripping means 20, the coating layer is cut off and removed by the cutting blades 26.

Here, the coating means 14 and the stripping means 16
Can be applied as long as it is a known technique.
However, the present invention is not limited to this structure. Similarly, it should be noted that the illustrated embodiment is merely an example and is not intended to limit the technical scope of the present invention.

[0027]

The effects of the present invention are listed below.

(1) Even when the freezing range exists in a deep underground area (deep depth area), the pipe refilling work unlike the prior art is not required.

(2) The members used (for example, coiled tubes) have sufficient strength required for the freezing method.

(3) Even if a freezing agent is injected, the non-freezing range is not frozen.

(4) When the tube (coiled tube) used after the freezing operation is wound up by a reel, the tube is prevented from becoming bulky.

(5) The used tube (coiled tube) can be reused for purposes other than the freezing method.

(6) No complicated equipment is required for implementation.

[Brief description of the drawings]

FIG. 1 is a sectional front view of one embodiment of the present invention.

FIG. 2 is a diagram illustrating a heat insulating material covering means used in the present invention.

FIG. 3 is a diagram illustrating an embodiment of stripping off a heat insulating material in the present invention.

FIG. 4 is a diagram illustrating a peeling means used in the present invention.

FIG. 5 is a sectional front view illustrating a conventional freezing method.

[Explanation of symbols]

G ... ground 1 ... boring hole 2 ... triple pipe 3, 4, 5 ... section C ... freezing agent (brine) A ... freezing range B ... non-freezing range S Boundary level GS: Ground surface H: Heat insulation material 10: Coiled tube (seamless small-diameter metal tube) 12: Take-up reel 14: Heat insulation material coating means 16 ..Heat-insulating material injection nozzle 20: Stripping means 22, 24: Opening 26: Cutting blade

Continuation of front page (56) References JP-A-59-114320 (JP, A) JP-A-54-120107 (JP, A) JP-A-54-120108 (JP, A)

Claims (2)

(57) [Claims] 1. A freezing method in which a borehole is excavated in the ground to be frozen, a tube is inserted into the borehole, and a cryogen is injected through the tube. A step of covering the outer metal tube with a heat insulating material when the metal tube is inserted into the boring hole; Removing the heat insulating material coated on the metal tube when the metal tube is pulled out of the tube. 2. An apparatus for performing the freezing method according to claim 1, wherein the metal tube has a seamless small diameter, a take-up reel for winding and holding the metal tube, and a boring hole. Means for covering the outer peripheral portion of the metal tube with a heat insulating material when inserted, and means for peeling off the heat insulating material coated on the metal tube when pulled out from the boring hole. Characteristic device.