JP6960305B2 - Freezing pipe and freezing method - Google Patents

Description

The present invention relates to a freezing method for freezing the ground.

In the conventional freezing method, a boring hole for a freezing pipe is drilled by, for example, a drilling rod. After that, a freezing pipe is built in, the drilling rod is pulled out, and an air leakage test (refrigerant leakage test) is performed to confirm that the refrigerant does not leak, and then the refrigerant is supplied. When building a freezing pipe, the freezing pipes are welded all around each joint to prevent leakage of refrigerant.
Here, the work of welding the frozen pipes to each other requires a great deal of labor because the welded portion is required to be airtight and watertight in order to prevent the refrigerant from leaking.
Further, since the freezing tubes are welded together at the site to form a freezing tube, it is necessary to cut and disassemble the freezing tube by gas fusing when the freezing tube is removed after freezing is completed. Therefore, the cut freezing tube cannot be reused, and it is necessary to prepare a so-called new freezing tube every time the freezing work is performed, resulting in high material cost.
Further, in the case of limited freezing, a great deal of labor is required for the work of arranging the heat insulating material, such as the work of winding a half-split pipe member or the like, which is a heat insulating material made of Styrofoam, around the region of the freezing pipe corresponding to the region where the ground is not frozen.
There is a request to reduce the cost of the entire freezing method by reducing the above-mentioned great labor, but a technique to meet the request has not yet been proposed.

Here, as the freezing pipe, a double pipe or a triple pipe is built based on the boundary depth between the region where the ground is frozen (frozen region) and the region where the ground is not frozen (non-frozen region). In the non-freezing area (non-freezing area), the work of insulating the inner pipe or the annular space between the inner pipe and the outer pipe, for example, the work of wrapping a half-split pipe member, which is a styrofoam heat insulating material, around the inner pipe (insulating material). Perform the work of arranging), etc. to construct a limited freezing tube.
In addition, since the freezing pipes are joined by welding as described above and a styrofoam material is used as the heat insulating material, not only special treatment is required to prevent the heat insulating material from melting due to the heat of welding, but also a fire can occur. The occurrence must also be noted.

As another conventional technique, a technique has been proposed in which the ground is cut by a double pipe and brine is supplied from the inner pipe and discharged into the outer pipe by switching the valve (for example, Patent Document 1).
However, since the prior art (Patent Document 1) excavates using a double pipe and uses the double pipe as it is as a freezing pipe, it has a region that does not freeze in the vertical direction (freezing pipe axial direction). Difficult to apply to limited freezing. Further, in the conventional technique of supplying brine from the inner pipe of the double pipe and flowing it out into the outer pipe after drilling a hole with the double pipe, a mechanism for switching between cutting water and a refrigerant slides the inner pipe upward. Therefore, the refrigerant cannot be supplied to the tip side of the inner pipe. Therefore, the ground around the tip of the freezing pipe could not be frozen. And since the ground around the tip cannot be frozen, in the prior art, it was necessary to drill an extra hole in order to freeze the required length.

Japanese Patent No. 3681363

The present invention has been proposed in view of the above-mentioned problems of the prior art, and it is not necessary to weld and join the freezing tubes to each other, and the freezing tubes can be reused as a structure that can be easily assembled and / or disassembled. The purpose is to provide a freezing tube and a freezing method that can be applied to limited freezing.

The freezing tube of the present invention has a boring head (30) screwed and connected to the tip, and a plurality of drilling rods (for example, a standard length rod having a unit length and a male threaded portion) having a sealing performance at the connection point. It is composed of a rod in which a plurality of O-rings are fitted to the rod), and has a seamless refrigerant supply pipe (6: for example, a coiled tube) inserted into the drilling rod (10).
The drilling rod (10) functions as a freezing pipe outer pipe (10) after the refrigerant supply pipe (6) is inserted, and is removable from the freezing pipe outer pipe (10) and the freezing pipe outer pipe (10). ) And the refrigerant header (refrigerator circulation header 20) communicating with the region between the refrigerant supply pipe (6) and the constituent members of the freezing pipe (100) are connected or assembled by screwing and unscrewed. by it can be decomposed into member unit,
The boring head (30) at the tip of the drilling rod is provided with a valve mechanism (3) that opens at the pressure of the drilling water (W) but closes at the supply pressure of the refrigerant (R). , The freezing pipe extends in the axial direction of the freezing pipe (100) and branches from the axial flow path (4) through which the drilled water (W) and the refrigerant (R) flow, bypassing the valve mechanism (3). It is characterized in that a refrigerant flow path (5) for supplying the refrigerant (R) to the tip is formed.

In the case of limited freezing in the freezing tube of the present invention, an inner tube (2A) having a sealing performance at the connection point and screwed is arranged inside the outer tube (10) of the freezing tube, and has a heat insulating layer. The double pipe portion (2) and the single pipe portion (1) having no heat insulating layer are formed, and the inner pipe (2A) is provided with a mechanism for urging downward in the pipe axis direction, and the double pipe portion (2) is provided. ) And the single pipe part (1), a frozen pipe made of a material (for example, MC nylon resin, polyamide resin, hard rubber, etc.) that has both rigidity to transmit the drilling torque at the time of drilling and heat insulation in the pipe axis direction. A heat insulating joint portion (2C) in which both ends are screwed to the outer pipe (10), and an inner pipe (2A) and an outer pipe (2A) of the double pipe portion (2) that are detachable from the freezing pipe outer pipe (10). It is preferable to have a heat insulating header (40) communicating with the region between the pipes (2B).

The freezing method of the present invention has a boring head (30) screwed and connected to the tip, and drilled water using a plurality of drilling rods (10) whose connection points have sealing performance and are screwed and connected. The boring hole is drilled while injecting (W), and the drilling head (30) at the tip of the drilling rod (10) is opened by the pressure of the drilling water (W), but the refrigerant (R) is supplied. A valve mechanism (3) that closes the valve under pressure is provided, and after drilling a boring hole, the drilling rod (10) remains in the ground to be frozen, and a seamless refrigerant is provided in the drilling rod (10). The supply pipe (6) is inserted, and the drilling rod (10) functions as a freezing pipe outer pipe (10) after the refrigerant supply pipe (6) is inserted, and the refrigerant is supplied from the refrigerant supply pipe (6). The refrigerant (R) bypasses the valve mechanism (3) and reaches the tip of the freezing pipe (100) via the axial pipe extending in the axial direction of the freezing pipe and the refrigerant flow path (5), and freezes. The freezing pipe outer pipe (10) and the refrigerant supply pipe (6) are detachable from the freezing pipe outer pipe (10) via the region between the pipe outer pipe (10) and the refrigerant supply pipe (6). The refrigerant (R) is discharged from the refrigerant header (20) communicating with the region between the two.

In the freezing method of the present invention, in the case of limited freezing, the connection portion forming the heat insulating space with the drilling rod (10) inside the drilling rod (10) has a sealing performance and is screwed and connected. A double pipe portion (2) having a heat insulating layer and a single pipe portion (1) having no heat insulating layer are formed by the pipe (2A), and the inner pipe (2A) is provided with a mechanism for urging downward in the pipe axial direction. Prepare,
At the boundary between the double pipe portion (2) and the single pipe portion (1), both ends of the drilling rod (10) are made of a material having both rigidity to transmit the drilling torque at the time of drilling and heat insulation in the pipe axis direction. Between the heat insulating joint portion (2C) screwed and connected to the freezing pipe outer pipe (10) and the inner pipe (2A) and outer pipe (2B) of the double pipe portion (2). It is preferable to have a heat insulating material header (40) communicating with the region, and to insulate the heat insulating space by lowering the pressure of the heat insulating material header.

In the freezing method of the present invention, in the case of limited freezing, the connection portion forming the heat insulating space with the drilling rod (10) inside the drilling rod (10) has a sealing performance and is screwed and connected. A double pipe portion (2) having a heat insulating layer and a single pipe portion (1) having no heat insulating layer are formed by the pipe (2A), and the inner pipe (2A) is provided with a mechanism for urging downward in the pipe axial direction. Prepare,
At the boundary between the double pipe portion (2) and the single pipe portion (1), both ends of the drilling rod (10) are made of a material having both rigidity to transmit drilling torque at the time of drilling and heat insulation in the pipe axis direction. Between the heat insulating joint portion (2C) screwed and connected, and the inner pipe (2A) and outer pipe (2B) of the double pipe portion (2) that is removable from the freezing pipe outer pipe (10). It is preferable to have a heat insulating material header (40) communicating with the region, and to insulate the heat insulating space by filling the heat insulating space with the heat insulating material header.

In the freezing method of the present invention, in the case of limited freezing, the connection portion forming the heat insulating space with the drilling rod (10) inside the drilling rod (10) has a sealing performance and is screwed and connected. A double pipe portion (2) having a heat insulating layer and a single pipe portion (1) having no heat insulating layer are formed by the pipe (2A), and the inner pipe (2A) is provided with a mechanism for urging downward in the pipe axial direction. Prepare,
At the boundary between the double pipe portion (2) and the single pipe portion (1), both ends of the drilling rod (10) are made of a material having both rigidity to transmit drilling torque at the time of drilling and heat insulation in the pipe axis direction. Between the heat insulating joint portion (2C) screwed and connected, and the inner pipe (2A) and outer pipe (2B) of the double pipe portion (2) that is removable from the freezing pipe outer pipe (10). It is preferable to have a heat insulating material header (40) communicating with the region, and to insulate by installing a heat insulating material in the heat insulating space by the heat insulating material header.

In the freezing method of the present invention, at the time of thawing, the refrigerant header (20) and the heat insulating material header (40) are removed, the inner pipe (2A) is removed, and the drilling rod (10) and the refrigerant supply pipe (6) are removed. A detachable thaw liquid header (60) is attached to the drilling rod (10), the thaw liquid is supplied from the refrigerant supply pipe (6), discharged from the thaw liquid header (60), and around the freezing pipe. It is preferable to thaw.

In the freezing method of the present invention, it is preferable that the freezing pipe constituent member is reused for new freezing by releasing the screw connection.

In the case of limited freezing in the freezing tube of the present invention, the inner tube (2A) of the double tube portion (2) of the freezing tube outer tube (10) is urged downward in the vertical direction to cause the inner tube (2A). , A mechanism (52, 54) that suppresses heat shrinkage due to the cold heat of the refrigerant (R) during freezing and pulling to the ground side, impairing the airtightness of the connection between the heat insulating joint (2C) and the inner pipe (2A). ) Is provided.
In the double pipe portion that is not frozen, a heat insulating layer is provided in the region between the outer pipe (2B) and the inner pipe (2A) to heat-shield the ground and the refrigerant (R). Therefore, at the time of freezing, a significant temperature difference occurs between the outer pipe (2B) in contact with the ground and the inner pipe (2A) in contact with the refrigerant (R), and the inner pipe (2A) contracts significantly with respect to the outer pipe (2B). Will be done.
When a frozen pipe is formed by welding like a conventional freezing pipe, the inner pipe (2A) and the outer pipe (2B) are also joined by welding, so that the inner pipe (2A) and the outer pipe (2B) are joined by welding. ), Even if there is a temperature difference, the continuity of the steel material is maintained and only thermal deformation occurs, and leakage of the refrigerant (R) does not occur.
In the present invention, each component of the freezing tube (100) is screwed and joined to have a structure that can be reused. In particular, when the freezing is completed and the frozen pipe is removed, the outer pipe (2B) remains as it is and the inner pipe (2A) is pulled out to the ground, so that the inner pipe (2A) and the heat insulating joint (2C) are separated. Airtightness is ensured by sandwiching a plurality of O-rings on the joint surface without screw joint. Therefore, in the present invention, it is preferable to provide the suppressing mechanism (52, 54).

In carrying out the present invention, in the valve mechanism (3), the valve body (3B) is seated on the valve seat (3C) by the elastic repulsive force of the spring (3A), and the elastic repulsive force of the spring (3A) is generated. It is adjusted to be weaker than the pressure of the drilling water (W) (at the time of drilling a boring hole) and stronger than the supply pressure of the refrigerant (R) (pressure directly above the valve body 3B at the time of supplying the refrigerant).

Further, in carrying out the present invention, the plurality of drilling rods (for example, standard length rods having a unit length) constituting the drilling rod (10) have a male screw formed at one end and a female screw formed at the other end. It is preferable that a plurality of sealing members (for example, two or more O-rings) are fitted in the vicinity.
Further, the refrigerant header (20) and the heat insulating material header (40) are also screwed and connected to the drilling rod (10) with male and female threads, respectively, and a plurality of sealing members (for example, two or more O-rings) are formed. It is fitted and airtightness and watertightness are ensured.
Therefore, since the constituent members are screw-connected, they can be disassembled into individual constituent members simply by releasing the screwing when the freezing is completed and the members are pulled out, disassembled, or removed. Can be reused.

In the present specification, the freezing tube outer tube (10) may be referred to as a drilling rod (10).
For example, as shown in FIG. 1 showing a process of drilling a boring hole in the ground G, the drilling rod (10) has a single pipe portion (1) on the drilling side (underground side) and is on the ground side. Is composed of an outer pipe (2B) of a double pipe portion.
The freezing method of the present invention is composed of a plurality of drilling rods (for example, a standard length rod having a unit length in which a plurality of O-rings are fitted in the vicinity of a male thread portion) at a connection point having sealing performance. A drilling rod (10) having a single pipe portion (1) and a double pipe portion (2) is used to drill a boring hole while injecting drilling water (W), and the tip of the drilling rod (10) is drilled. The boring head (30) is provided with a valve mechanism (3) that opens at the pressure of the drilled water (W) but remains closed at the supply pressure of the refrigerant (R).
After drilling, the drilling rod (10) remains on the ground to be frozen, a seamless refrigerant supply pipe (6: for example, a coiled tube) is inserted into the drilling rod (10), and the drilling rod (10) is inserted. ) Functions as a freezing pipe outer pipe (10) after the refrigerant supply pipe (6) is inserted.
A heat insulating header (40) is used to insulate the region (α) between the inner pipe (2A) and the outer pipe (2B) of the double pipe portion (2).
The refrigerant (R) is supplied from the refrigerant supply pipe (6), and the refrigerant (R) is valved through the axial flow path (4) and the refrigerant flow path (5) extending in the axial direction of the freezing pipe (100). After bypassing the mechanism (3) and reaching the tip of the freezing pipe (100), it flows through the region (β) between the single pipe portion (1) and the refrigerant supply pipe (6), and then flows through the double pipe portion (2). The refrigerant is discharged from the refrigerant header (refrigerant circulation header 20) through the region (β) between the inner pipe (2A) and the refrigerant supply pipe (6).

In the present invention, the refrigerant (R) may be brine or liquefied carbon dioxide (CO ₂ ), and there are no particular limiting conditions.
Here, when a refrigerant cooling facility is provided on the ground side, for example, when liquefied carbon dioxide is used as the refrigerant (R), the refrigerant cooling facility on the ground side is provided so that the refrigerant (R) takes heat of vaporization from the ground. It is configured as a circulation cooling mechanism that cools the gas-liquid mixed carbon dioxide discharged from the freezing tube outer tube (10) and supplies it as liquid phase carbon dioxide (liquefied carbon dioxide) to the freezing tube outer tube (10). preferable. Similarly, when the refrigerant (R) is brine, it is preferable to use a circulation cooling mechanism that cools the brine discharged from the freezing pipe outer pipe (10) and supplies it to the freezing pipe outer pipe (10).

According to the present invention having the above-described configuration, after the drilling is completed to a predetermined position by the boring head (30) screwed and connected to the tip of the drilling rod (10) screwed and connected, the drilling rod With the (10) and the boring head (30) still configured, after draining the drilled water, the coiled tube, which is the refrigerant supply pipe (6), is inserted into the boring head (30), and the refrigerant header (30) If 20) is installed and a refrigerator and a circulating refrigerant pipe are installed, a freezing pipe for ground freezing work can be constructed. Then, the process of installing the freezing pipe by the welding connection of the prior art can be omitted.
Here, by forming the refrigerant supply pipe (6) with a seamless coiled tube, the refrigerant supply pipe (6) can be easily pulled out to the ground side.
Then, by easily pulling out the refrigerant supply pipe (6) to the ground side, additional drilling of the boring hole can be easily performed by using the drilling rod (10) which was the outermost pipe in the radial direction of the freezing pipe. Can be done.

Further, in the case of limited freezing, an inner pipe (2A) screwed and connected is installed inside the drilling rod (10) screwed and connected, and a double pipe portion (2) having a heat insulating layer (α) is installed. ) And a single pipe portion (1) having no heat insulating layer, and the inner pipe (2A) is provided with a mechanism for urging downward in the pipe axis direction, and the double pipe portion (2) and the single pipe portion (1) are provided. The heat insulating joint portion (2C) screwed and connected is provided at the boundary portion of the above, and the heat insulating material header (40) is installed at the upper end of the drilling rod (10) to remove the drilling water. The coiled tube which is the refrigerant supply pipe (6) is inserted into the boring head (30), the refrigerant header (20) is installed, the refrigerator and the circulating refrigerant pipe are connected, and the heat insulating layer (α) is in a vacuum heat insulating state, for example. If this is the case, a limited freezing pipe for ground freezing work can be constructed. Then, the process of installing the freezing pipe by the welding connection of the prior art can be omitted.
The double pipe portion (2) of the limited freezing pipe of the present invention has a triple pipe configuration, but the innermost refrigerant supply pipe (6) uses a seamless, for example, coiled tube, and the inner pipe outside the joint (6). Since the 2A) and the outer pipe (2B) are screw-connected, there is no surface unevenness in any of the pipes, and the freezing pipe constituent members can be assembled with high accuracy.
Therefore, the freezing pipe of the present invention can have a smaller freezing pipe diameter (outermost diameter) than the conventional freezing pipe of about 100 mm, as compared with the frozen pipe assembled by conventional welding. In the prototype experiment of the inventor, it has been confirmed that an outer diameter of about 60 mm exhibits sufficient freezing performance and heat insulating performance, and it is possible to further reduce the diameter.
Since the freezing tube of the present invention can be made smaller in diameter than the conventional freezing tube, the drilling machine required for drilling can be miniaturized and the drilling speed can be increased.

According to the prior art, a hollow tube is airtightly welded to form a freezing tube, and when the freezing tube is removed, when the freezing tube is pulled up to a predetermined length, cutting using a firearm such as gas cutting is performed. I had to do it. And the freezing tube cut by the firearm could not be reused.
On the other hand, according to the present invention, the connection portion is composed of a plurality of drilling rods having sealing performance (for example, a standard length rod having a unit length and a rod in which a plurality of O-rings are fitted to a male thread portion). It is reused as a freezing pipe, and after thawing the frozen ground, it is pulled out to the ground side while releasing the connection (for example, screwing) between the drilling rods constituting the freezing pipe outer pipe (10). , The drilling rod that has been disconnected can be reused. Further, since the freezing pipe constituent members other than the drilling rod are also screwed and connected, basically all the frozen pipe constituent members can be reused except for consumable parts.

The drilling rod (10) used for drilling a boring hole is used repeatedly by cutting and joining a plurality of drilling rods (for example, standard length rods having a unit length) whose connection points have sealing performance. It is possible to handle various construction depths by appropriately combining rods of unit length. Further, since it is not necessary to manufacture a pipe for drilling a special length for various construction depths, the cost of the freezing method can be reduced.
Here, as a drilling rod (for example, a standard length rod) whose connection point has sealing performance, for example, a standard length rod having a unit length and a rod in which a plurality of O-rings are fitted in the vicinity of the male thread portion is used. It is possible to omit the joint leakage inspection at the construction site.

In the present invention, if a valve structure (3) of a type in which the valve body (3B) is seated on the valve seat (3C) by the elastic repulsive force of the spring (3A) is used, the drilling water (drilling water at the time of drilling a boring hole) ( By adjusting the pressure of W) to be stronger than the spring repulsive force and the supply pressure of the refrigerant (R) to be weaker than the spring repulsive force, the valve is opened when the drilled water (W) is discharged. During the freezing operation, the closed state is automatically performed, and no special operation is required.

According to the present invention, since the refrigerant flow path (5) for supplying the refrigerant (R) is formed at the tip of the freezing pipe (100), the refrigerant (R) reaches the region at the tip of the freezing pipe (100). It is possible to freeze by applying cold heat to the ground region beyond the tip of the freezing pipe (100) in the extension direction of the freezing pipe (100).
Therefore, for example, when the shield machine approaches the shaft, the area between the shaft and the tip of the shield machine is frozen. Since the area can be frozen, if the freezing pipe is placed near the shaft, the area between the shield machine and the shaft can be frozen without drilling a part of the wall of the shaft. Therefore, when arranging the freezing pipe, it is not necessary to drill a part of the wall of the shaft, and the wall of the shaft is not damaged.

According to the present invention, since the drilling rod (10) functions as the freezing tube outer tube (10), the outer tube portion of the freezing tube (100) (freezing tube if limited freezing is not performed) at the same time as the drilling of the boring hole is completed. Outer tube 10: In the case of limited freezing, the installation of the freezing tube outer tube 10 and the freezing tube inner tube 2A) is completed.
Therefore, it is possible to omit a plurality of steps of inserting the freezing tube and pulling out the drilling rod.

In the present invention, in the case of limited freezing, the region (α) between the inner pipe (2A) and the outer pipe (2B) of the double pipe portion (2) is insulated by using the heat insulating material header (40). Therefore, the region (α) has a high heat insulating property, and the cooling heat of the refrigerant (R) flowing inside the inner pipe (2A) of the double pipe portion (2) is the inner pipe (2A) and the outer pipe (2A). It is insulated in the region (α) between 2B) and is not transferred to the ground near the double pipe portion (2). Therefore, the ground near the double pipe portion (2) of the freezing pipe outer pipe (10) does not freeze.
When insulating the region (α) between the inner pipe (2A) and the outer pipe (2B), the double pipe portion (2) of the frozen pipe outer pipe (10) is used by using the heat insulating material header (40). The region (α) between the inner tube (2A) and the outer tube (2B) of the above is decompressed at the time of freezing, for example by evacuation, or filled with adiabatic gas (or adiabatic liquid).
Here, depressurizing by vacuuming or filling with a heat insulating gas (or heat insulating liquid) is much easier than the work of wrapping a heat insulating material around the outer circumference of the inner pipe in the prior art, and workability is improved. Is good. Therefore, the limited freezing can be easily performed as compared with the method of installing the heat insulating material between the inner pipe and the outer pipe.

According to the present invention, the boundary depth between the frozen region and the non-frozen region of limited freezing is the position of the single tube portion (1) and the position of the double tube portion (2) in the frozen tube outer tube (10) (each of them. It can be set freely by changing the length) as appropriate.
In the method of installing the heat insulating material between the inner pipe and the outer pipe, such as wrapping the heat insulating material around the outer circumference of the inner pipe, the installed heat insulating material must be removed in order to reuse the inner pipe. It takes a lot of effort. On the other hand, according to the method of decompression by evacuation or filling with adiabatic gas (or adiabatic liquid), the pressure in the region decompressed by evacuation is increased to atmospheric pressure, or the adiabatic gas (or filled) is filled. By discharging the adiabatic liquid), the adiabatic state can be easily released and the double pipe portion (2) can be made a reusable state.

Further, in the present invention, in the case of limited freezing, a heat insulating joint portion (2C) is provided at the boundary between the double pipe portion (2) and the single pipe portion (1) of the frozen pipe outer pipe (10), and the heat insulating joint portion (2C) is provided. ) Is composed of a heat insulating material (for example, MC nylon resin, polyamide resin, hard rubber, etc.), the cold heat of the refrigerant (R) is transferred to the outer pipe (2B) of the double pipe portion (2). Is prevented, and the ground in the non-freezing portion is also prevented from freezing.
Since the heat insulating joint portion (2C) is also a joining member of the drilling rod (10), the drilling torque given from the ground at the time of drilling is applied to the drilling torque from the ground side drilling rod (10) to the underground side. Since it also has the rigidity to transmit the force to the rod (10), the drilling torque from the drilling machine on the ground can be transmitted to the tip of the drilling rod (10) to drill the ground.

In the present invention, in the case of limited freezing, the inner pipe (2A) of the double pipe portion (2) of the freezing pipe outer pipe (10) is urged downward in the vertical direction, and the inner pipe (2A) is thermally contracted to the ground. If a mechanism (52, 54) for suppressing pulling to the side is provided, the force for urging the inner pipe (2A) downward in the vertical direction will cause the inner pipe (2A) to be pulled up to the ground side by heat shrinkage. To offset the power to. As a result, the inner pipe (2A) is prevented from being pulled up to the ground side, and the O-ring in the lowermost inner pipe (2A) of the double pipe portion (2) (because the inner pipe 2A is pulled up to the ground side). The action of shearing force on (25) is suppressed. Then, damage to the O-ring (25) in the lowermost inner pipe (2A) of the double pipe portion (2) and the accompanying deterioration of the sealing performance are prevented.

In the present invention, at the time of thawing, the refrigerant header (20) and the heat insulating material header (40) are removed, the inner pipe (2A) of the double pipe portion (2) is removed, and the outer pipe (2) of the double pipe portion (2) is removed. The thawing liquid header (60) is attached to the outer pipe (2B) of the double pipe portion (2), leaving the 2B) and the refrigerant supply pipe (6) on the underground side, and the thawing liquid is discharged from the refrigerant supply pipe (6). If the thaw liquid that has been supplied and returned to the ground side from the area between the outer pipe (2B) and the refrigerant supply pipe (6) is discharged from the thaw liquid header (60), the inner pipe of the double pipe portion (2) is discharged. Since (2A) has already been extracted, the thaw liquid supplied from the refrigerant supply pipe (6) is above the ground through the hollow portion in the radial direction of the outer pipe (2B) of the double pipe portion (2). Returning to the side, the amount of heat retained by the thaw liquid is transmitted not only to the ground on the radial outer side of the single pipe portion (1) but also to the ground on the radial outer side via the outer pipe (2B) of the double pipe portion 2. Will be done. Therefore, even if the ground in the non-frozen region is frozen, it can be reliably unfrozen with the thaw liquid.

Further, according to the present invention, when removing the freezing pipe, it is sufficient to disconnect the drilling rods from each other, it is not necessary to cut gas or the like, and it is not necessary to use a firearm. Therefore, the safety of the freezing pipe removal work is improved. In addition, since it does not use firearms, it also contributes to environmental conservation.
According to the present invention, when the freezing pipe outer pipe (10) is pulled out, the filler (landfill material for filling the boring hole) can be discharged from the tip, so that the freezing pipe outer pipe (10) is pulled out. At the same time, it is possible to fill the hole in the drilled space, prevent the thawed surrounding ground from collapsing, and the filling work is easy.

It is sectional drawing which shows the process of excavating a boring hole in embodiment of this invention. It is sectional drawing which shows the process of inserting a refrigerant supply pipe in an embodiment. It is sectional drawing which shows the step of supplying a refrigerant and freezing the ground in an embodiment which does not perform limited freezing. It is sectional drawing which shows the step of supplying the refrigerant and freezing the ground in the embodiment which performs limited freezing. It is sectional drawing which shows the ground side part in embodiment. It is sectional drawing which shows the boundary between the double tube part and the single tube part of the freezing tube outer tube in embodiment. It is sectional drawing which shows the step which shows the process of removing the ground side member for thawing in embodiment. It is sectional drawing which shows the process following FIG. 7 in the procedure of removing a member on the ground side for thawing. It is sectional drawing which shows the process following FIG. 8 in the procedure for removing a member on the ground side for thawing. It is a partial cross-sectional enlarged view which shows the tip on the underground side of the freezing tube used in embodiment. FIG. 10 is a cross-sectional view taken along the line AA in FIG. FIG. 10 is an end view (arrow view B) of the tip portion in FIG. 10, and is a view for explaining a drilling bit and a drilling water injection port provided at the underground tip of the freezing pipe used in the embodiment. be.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
In the illustrated embodiment, the freezing tube is indicated by reference numeral 100 in its entirety. In the present specification, the freezing tube outer tube 10 may be referred to as a “drilling rod 10”.
Here, FIGS. 1 and 2 show a case where limited freezing is performed, and FIG. 3 shows a case where limited freezing is not performed.
FIG. 1 shows a step of drilling a boring hole in the ground G when performing limited freezing. In FIG. 1, the drilling rod 10 is composed of a single pipe portion 1 on the drilling side (underground side). The ground side is composed of the outer pipe 2B of the double pipe portion 2.
Although not clearly shown, the single pipe portion 1 and the double pipe portion 2 are configured by connecting (connecting) drilling rods (standard length rods) having a unit length, respectively. The drilling rod (rod of unit length) has a male screw (not shown) formed at one end and a female screw (not shown) at the other end, and the male screw and the female screw are screwed together to form a standard length. Connect the rods together. Then, by appropriately setting the length of the single pipe portion 1 and the length of the double pipe portion 2 in the outer pipe 2B, it is possible to correspond to various construction conditions.
Here, the screwed portion between the rods in the drilling rod 10 has high airtightness and watertightness so that the refrigerant R does not leak when the drilling rod 10 is reused as the freezing pipe outer pipe 10. For example, a plurality of (for example, two or more) O-rings are fitted to a male screw.

The boring head 30 at the tip of the drilling rod 10 is provided with a valve mechanism 3 that opens at the pressure of the drilling water W but closes at the supply pressure of the refrigerant R, and is provided on the drilling side of the single pipe portion 1 ( A drilling bit portion 7 (FIGS. 10 and 12) is arranged at the tip (on the underground side). Further, the hollow portion of the single pipe portion 1 constitutes a flow path for the drilled water W, and a guide portion 4T for inserting the refrigerant supply pipe 6 (coiled tube; see FIG. 2) is provided at the tip thereof. The guide portion 4T also functions as a flow path through which the drilled water W flows.
The valve mechanism 3 is composed of a spring 3A (FIG. 10), a spherical valve body 3B (FIG. 10), and a valve seat 3C (FIG. 10), the details of which will be described later. Further, a drilling bit portion 7 arranged at the tip (underground side end portion) of the drilling rod 10 and having an injection port 7B formed therein will also be described later with reference to FIGS. 10 and 12.
As described above, the single pipe portion 1 and the double pipe portion 2 are composed of a plurality of standard length (unit length) single pipes and double pipes, respectively.

In FIG. 1, a region α having an annular cross section is formed between the inner pipe 2A and the outer pipe 2B of the double pipe portion 2. When performing limited freezing in which a non-freezing region exists, the region α having an annular cross section is decompressed to an extremely low pressure, for example by evacuation, or is filled with an adiabatic fluid (adiabatic gas or adiabatic liquid) and doubled. A high heat insulating region is formed between the inner pipe 2A (refrigerant flow path) of the pipe portion 2 and the ground G.
At the time of drilling, the hollow portion of the inner pipe 2A constitutes the flow path of the drilling water W.
In the vicinity of the boundary between the double pipe portion 2 and the single pipe portion 1, a heat insulating joint portion 2C having a heat insulating function and blocking the transmission of cold heat is provided, and the heat insulating joint portion 2C is the region α (annular cross section). Region α) is blocked from the hollow portion of the single tube portion 1. The connection portion between the double pipe portion 2 and the single pipe portion 1 will be described later.

In the construction of the freezing method, first, as shown in FIG. 1, a boring hole is drilled in the ground G to be frozen by the drilling rod 10. At the time of drilling, the ground G is drilled by the drilling bit portion 7 while injecting the drilling water W from the tip of the drilling rod 10.
The drilled water W is supplied from a water source (not shown) on the ground side, flows through the hollow portion of the inner pipe 2A of the double pipe portion 2 and the hollow portion of the single pipe portion 1, and flows through the hollow portion of the single pipe portion 1 to the tip portion (ground) of the single pipe portion 1. It is supplied to the middle end) (arrow W1). When the drilled water W reaches the valve mechanism 3, the valve mechanism 3 is opened against the elastic repulsive force of the spring 3A of the valve mechanism 3. Then, the drilling water W is discharged into the ground from the injection port 7B (see FIGS. 10 and 12) formed in the drilling bit portion 7 arranged at the tip of the drilling rod 10 (arrow W2).
The discharged drilling water W passes through the outer wall of the drilling rod 10 (single pipe portion 1, double pipe portion 2) and returns to the ground side (arrow W3).
Even when the limited freezing is not performed (FIG. 3), the step of drilling a boring hole in the ground G is the same as described with reference to FIG.

After drilling a boring hole in the ground G with the drilling rod 10, the drilling rod 10 remains in the ground G to be frozen as it is. The remaining drilling rod 10 functions as an outer pipe of the freezing pipe when the ground G is frozen.
In other words, the drilling rod 10 becomes the freezing pipe outer pipe 10 or the outer pipe 2B or the single pipe 1 of the double pipe portion after drilling a predetermined boring hole. The pipe portion 1 or the double pipe portion 2 is arranged. As described above, in the illustrated embodiment, both the drilling rod and the freezing tube outer tube are indicated by reference numeral 10.
In the prior art, a plurality of steps of inserting a freezing tube and pulling out a drilling rod after drilling a boring hole are performed, but for the above-mentioned reason, the plurality of steps are unnecessary in the illustrated embodiment.

In the process shown in FIG. 2, a seamless long coiled tube 6 is inserted into the drilling rod 10. In the present invention, after the coiled tube 6 which is the refrigerant supply pipe is inserted, the drilling rod 10 becomes the freezing pipe outer pipe 10. That is, before the step shown in FIG. 2, reference numeral 10 indicates a drilling rod, but as shown in FIG. 2, after the coiled tube 6 is inserted, reference numeral 10 indicates a freezing tube outer tube.
Since the coiled tube 6 has no seams and is long, it is not necessary to perform a seam when inserting it into the ground, and there is no risk of refrigerant leaking, so that the coiled tube 6 can be easily arranged.
In the illustrated embodiment, the refrigerant R may be brine or liquefied carbon dioxide (CO ₂ ), and there is no particular limitation. Although not clearly shown, a refrigerant cooling facility on the ground side is provided, and when the refrigerant R is liquefied carbon dioxide, for example, the refrigerant R is discharged from the freezing tube outer pipe 10 so as to take the heat of vaporization from the ground. It is configured as a circulation cooling mechanism that cools the gas-liquid mixed carbon dioxide to form a liquid phase and supplies the carbon dioxide in the liquid phase to the freezing tube outer tube 10. Similarly, when the refrigerant R is brine, the circulation cooling mechanism is such that the brine discharged from the freezing pipe outer pipe 10 is cooled and supplied to the freezing pipe outer pipe 10.

In FIG. 2, the coiled tube 6 inserted inside the freezing pipe outer pipe 10 is hollow of the inner pipe 2A of the double pipe portion 2 of the freezing pipe outer pipe 10 (double pipe portion 2 of the drilling rod 10). It has passed through the portion and is inserted into the single pipe portion 1 of the freezing pipe outer pipe 10 (single pipe portion 1 of the drilling rod 10). The coiled tube 6 is inserted and held in the coiled tube tip insertion portion 4B (see FIG. 10) in front of the valve mechanism 3 (ground side).
As shown in FIG. 2, the single tube portion 1 of the freezing tube outer tube 10 has a structure similar to that of a double tube with the coiled tube 6 inserted. The double tube portion 2 of the freezing tube outer tube 10 has a structure similar to that of the triple tube when the coiled tube 6 is inserted.
Even when the limited freezing is not performed (FIG. 3), the step of inserting the coiled tube 6 into the boring head 30 is the same as described with reference to FIG.

As shown in FIG. 10, the valve mechanism 3 is configured to press the valve body 3B against the valve seat 3C by the elastic repulsive force of the spring 3A.
By using such a valve mechanism, the valve mechanism 3 can be reliably opened and closed regardless of whether the freezing pipe 100 is arranged horizontally or upward.

The state in which the freezing method without limited freezing is carried out is shown in FIG.
In FIG. 3, the drilling rod 10 is composed of a single pipe, and the boring head 30 at the tip of the drilling rod 10 is provided with a valve mechanism 3 that opens the valve at the pressure of the drilling water but closes at the supply pressure of the refrigerant. A drilling bit portion 7 is arranged at the tip of the drilling rod 10 on the drilling side (underground side).
The drilling rod 10 is reused as the freezing pipe outer tube 10 after drilling the boring hole. A refrigerant header 20 is attached to the ground side of the freezing pipe outer pipe 10.
The refrigerant supplied from the refrigerant introduction portion 21 (arrow R1) of the refrigerant header 20 passes through the coiled tube 6, and the refrigerant R opens the valve mechanism 3 in the vicinity of the underground end of the freezing pipe outer pipe 10. Without (arrow R2), it flows through the hollow portion of the freezing tube outer tube 10 (arrow R3). The refrigerant R flowing through the hollow portion of the freezing pipe outer pipe 10 is returned from the refrigerant return port 22 of the refrigerant header 20 (arrow R4).
When flowing through the freezing pipe outer pipe 10 (arrow R3), the cold heat of the refrigerant is transmitted to the ground near the freezing pipe outer pipe 10, and the ground near the single pipe outer freezing pipe 10 freezes.

The state of performing limited freezing is shown in FIG. In FIG. 4, a refrigerant header 20 and a heat insulating material header 40 are attached to the ground side of the freezing pipe outer pipe 10. The refrigerant header 20 is connected to the inner pipe 2A of the double pipe portion, and the heat insulating material header 40 is connected to the annular region α between the outer pipe 2B and the inner pipe 2A of the double pipe portion.
As shown in FIG. 4, the refrigerant header 20 has a refrigerant introduction portion 21 and a refrigerant return port 22, and a coiled tube 6 is inserted into the refrigerant introduction portion 21. The above-ground end of the coiled tube 6 is connected to a above-ground refrigerant supply mechanism (not shown). The refrigerant return port 22 is a return port for the refrigerant that has finished cooling work in a predetermined area in the ground to flow through a flow path described later and finally to be discharged to the outside of the freezing pipe outer pipe 10. It is connected to a refrigerant return channel (not shown) on the ground.

The heat insulating material header 40 has a heat insulating material introducing portion 41, and the heat insulating material introducing portion 41 is for vacuuming a region α having an annular cross section between the inner pipe 2A and the outer pipe 2B of the double pipe portion. It is a connection port and communicates with a decompression device (not shown) on the ground. Alternatively, the heat insulating material introduction portion 41 is a connection port for introducing the heat insulating fluid into the region α, and communicates with the heat insulating fluid source (not shown) on the ground.
When the heat insulating fluid is released when the heat insulating fluid is used (see FIGS. 7 to 9), the heat insulating fluid is discharged from the heat insulating material introduction portion 41. When the region α is depressurized (or evacuated), outside air is introduced from the heat insulating material introduction portion 41 to boost the region α and return it to, for example, atmospheric pressure.
As for the heat insulation of the region α, an example of evacuating or introducing a heat insulating fluid from the heat insulating material introduction portion 41 is shown as described above. It is also possible to install a heat insulating material between the inner pipe and the outer pipe by a method such as winding around the pipe (2A).
In FIG. 4, a low temperature shrinkage leakage prevention device 11 is provided in the vicinity of the above-ground side end of the inner pipe 2A of the double pipe portion of the freezing pipe outer pipe 10. The low temperature shrinkage leakage prevention device 11 will be described later with reference to FIG.

FIG. 4 shows a case where limited freezing is performed in which only a part of the underground side (the region on the deep side) is frozen in a limited manner.
In the limited freezing shown, the region to be frozen (freezing region) is a vertical region corresponding to the single tube portion 1 of the freezing tube outer tube 10, and the region not to be frozen (non-freezing region) is the freezing tube outer tube 10. It is a vertical region corresponding to the double pipe portion 2.

When performing limited freezing, prior to supplying the refrigerant R by the coiled tube 6, a decompression device (not shown) is operated to form the inner pipe 2A and the outer pipe 2B of the double pipe portion of the freezing pipe outer pipe 10. The region α having an annular cross section between them is depressurized to a vacuum or a low pressure state close to vacuum. Alternatively, an adiabatic fluid source (not shown) is operated to fill the region α with the adiabatic fluid.
By making the region α having an annular cross section into a vacuum or a low pressure close to vacuum, or by making the region α filled with an adiabatic fluid (insulating gas or adiabatic liquid), the region α having an annular cross section has high heat insulating properties. Have.

In FIG. 4, the supplied refrigerant R passes through the coiled tube 6 (arrow R1), passes through the double pipe portion 2 of the freezing pipe outer pipe 10, and is underground in the single pipe portion 1 of the freezing pipe outer pipe 10. Reach near the side edge.
In the vicinity of the underground end of the freezing pipe 100, the refrigerant R does not open the valve mechanism 3 (arrow R2), and the hollow portion of the single pipe portion 1 (between the inner wall of the single pipe portion 1 and the coiled tube 6). It flows through space β) (arrow R3). Here, the refrigerant shown by the arrow R2 or a part thereof flows in the vicinity of the underground end portion of the freezing pipe 100, and the details thereof will be described later with reference to FIG.

The refrigerant R flowing through the hollow portion of the single pipe portion 1 passes through the annular space between the inner wall of the inner pipe 2A and the coiled tube 6 in the double pipe portion 2 (arrow R4), and the refrigerant header 20 of the refrigerant header 20 It is returned from the refrigerant return port 22 to the refrigerant return flow path (not shown) on the ground (arrow R5).
When flowing through the single pipe portion 1 of the freezing pipe outer pipe 10 (arrow R3), the cold heat of the refrigerant R is transmitted to the ground near the single pipe portion 1, and the ground near the single pipe portion 1 freezes. In the double pipe portion 2 of the freezing pipe outer pipe 10, the cold heat of the refrigerant R is cut off in the region α having an annular cross section, so that the cold heat of the refrigerant R is not transferred to the ground in the vicinity of the double pipe portion 2. , The ground at the vertical position corresponding to the double pipe portion 2 of the freezing pipe outer pipe 10 does not freeze. That is, in FIG. 4, the ground near the single pipe portion 1 on the underground side freezes, but the ground near the double pipe portion 2 on the ground side does not freeze, and limited freezing is performed.

The boring head 30 near the underground end of the freezing pipe outer pipe 10 has a function of connecting the single pipe portion 1 of the freezing pipe outer pipe 10 and the drilling bit portion 7.
Although details will be described later, a refrigerant flow path through which the refrigerant R flows is formed inside the boring head 30 (see FIGS. 10 to 12).

In the freezing step of FIG. 4, the configuration in the region on the ground side is shown in FIG. The details of the boundary portion between the single pipe portion 1 and the double pipe portion 2 shown in FIGS. 1, 2 and 4 are shown in FIG.
In FIG. 5, the outer pipe 2B of the double pipe portion is configured by connecting rods having a unit length (standard length rod 2BS) in the illustrated embodiment. The rods 2BS are joined by screwing a male screw and a female screw, and O-rings 48 are fitted at a plurality of places (two places in FIG. 5) in the vicinity of the male screw of the rod 2BS at the screwing points 46.
Therefore, the joint portion between the rods 2BS constituting the outer pipe 2 (or the single pipe portion 1) is provided with sufficient sealing performance so that the refrigerant R does not leak.
In FIGS. 5 to 9, the left side is the ground side and the right side is the underground side.

The ground side end of the outer pipe 2B in the double pipe portion 2 and the heat insulating header 40 are screwed at the connection portion 40J.
In the heat insulating material header 40, the heat insulating material introduction portion 41 is formed substantially in the center in the axial direction. The heat insulating material header 40 is formed with a cylindrical space 42 that communicates with the heat insulating material introduction portion 41 and opens to the underground side. A guide member screw portion F40 having a female screw formed is provided at the ground side end of the heat insulating material header 40, and a cylindrical seal mounting space 45 is formed adjacent to the guide member screw portion F40 to mount the seal. A seal member S40 is mounted in the space 45.

A guide member P40 having a male screw is screwed into the guide member screwing portion F40 of the heat insulating material header 40.
The seal mounting space 45 and the cylindrical space 42 are shielded by a partition wall 43, and the seal member S40 housed in the seal mounting space 45 is composed of, for example, rubber packing, so that the heat insulating material leaks or vacuum breaks (vacuum breakage). Pressure leakage) is prevented.
A connecting portion 62 is formed on the underground side of the connecting member 2AJ, and at the connecting portion 62, the underground side end portion (right end portion in FIG. 5) of the connecting member 2AJ is the above-ground side end portion (FIG. 5) of the inner pipe 2A. It is screwed with the left end of 5.

In FIG. 5, near the above-ground end of the inner pipe 2A of the double pipe portion, protrusions 52 are arranged (fixed) on the outer periphery in the radial direction so as to protrude outward in the radial direction at equal intervals in the circumferential direction. Has been done. A coil spring 54 is interposed between the protrusion 52 and the underground end portion 40e of the heat insulating material header 40. In other words, the protrusion 52 and the coil spring 54 constitute the low temperature shrinkage leakage prevention device 11, and by urging the inner pipe 2A, the inner pipe 2A is separated from the heat insulating joint portion 2C due to heat shrinkage. It prevents deterioration of the sealing performance of the O-ring 25.
Since the heat insulating material header 40 is screwed with the outer pipe 2B, in the state of FIG. 5, the distance (interval) L between the underground side end portion 40e of the heat insulating material header 40 and the above-ground surface of the protrusion 52 is L. Is constant, during which the coil spring 54 is interposed in a compressed state. If the free length of the coil spring 54 is Lsf (not shown) and the free length Lsf is longer than the interval L, the coil spring 54 is compressed and its elastic repulsive force is applied to the inner tube 2A via the protrusion 52 in FIG. It is urging to the right, that is, to the underground side.

Since the inner pipe 2A of the double pipe portion comes into contact with the refrigerant, it shrinks due to the cold heat of the refrigerant.
On the other hand, since the region α having an annular cross section between the inner pipe 2A and the outer pipe 2B of the double pipe portion is insulated, the cold heat of the refrigerant is blocked in the region α, and the outer pipe 2B of the double pipe portion is Does not shrink. Then, as will be described later, the heat insulating joint portion 2C of FIG. 6 is made of a heat insulating material.
Therefore, at the time of freezing, only the inner pipe 2A of the double pipe portion heat-shrinks (due to the cold heat of the refrigerant R), and the heat shrinkage causes a phenomenon equivalent to the force acting on the inner pipe 2A to pull it up to the ground side. If only the inner pipe 2A is pulled up to the ground side due to this, a shearing force acts on the O-ring 25 in FIG. 6 and there is a possibility of damage.

On the other hand, as described above with reference to FIG. 5, if the elastic repulsive force due to the compression of the coil spring 54 urges the inner tube 2A to the right side (underground side) of FIG. 5 via the protrusion 52. , The elastic repulsive force of the coil spring 54 (the elastic repulsive force that urges the inner tube 2A to the ground side) cancels out the force that tries to pull the inner tube 2A to the ground side due to heat shrinkage. That is, by introducing prestress into the coil spring 54 before the start of freezing and absorbing the heat shrinkage of the inner pipe 2A by the elongation of the prestress of the coil spring 54, the heat insulating joint on the underground side of the inner pipe 2A. The inner pipe 2A is prevented from being pulled up at the joint with the portion 2C.
As a result, it is suppressed that the inner pipe 2A is pulled up to the ground side, and the shearing force does not act on the O-ring 25 in FIG. 6 to prevent the O-ring 25 from being damaged. Therefore, the sealing performance of the portion where the O-ring 25 is provided is not deteriorated, and the leakage of the refrigerant R is prevented.

In FIG. 5, the inner pipe 2A is configured by adding a common ulnar canal 2AS.
In the illustrated example, the ground side end of the ulnar canal 2AS is formed with a female screw (reference numeral omitted), and the underground side end portion is formed with a male screw (reference numeral omitted). Then, by adding a plurality of standard-sized pipes 2AS, an inner pipe 2A having a predetermined length is formed.
Male screws (reference numerals omitted) are formed at both ends of the connecting member 2AJ. The ulnar canal 2AS forming the above-ground end of the inner pipe 2A is connected (screwed) to the connecting member 2AJ at the connecting portion 62.

The ground side end of the connecting member 2AJ is screwed with the refrigerant header 20. Here, a female screw (reference numeral is omitted) is formed at the underground side end portion 20e of the refrigerant header 20. On the other hand, the refrigerant introduction portion 21 of the refrigerant header 20 is formed with a female screw (reference numeral omitted) that is screwed with the plug member P20. The refrigerant header 20 penetrates through the communication hole 23, and the communication hole 23 communicates with the refrigerant return port 22. A cylindrical seal mounting space 27 for mounting the seal member S20 is formed on the ground side of the communication hole 23, and a partition wall 24 is formed on the underground side (right side in FIG. 5) of the seal mounting space 27. Has been done.
Reference numerals 26 in FIGS. 5 and 6 indicate a sealing member such as an O-ring.

A through hole P21 through which the coiled tube 6 is inserted is formed in the plug member P20, and a screw hole (reference numeral omitted) that is orthogonal to the through hole P21 and opens on the outer periphery of the plug member P20 is formed, and the screw 31 is screwed. It fits.
The coiled tube 6 is fixed to the refrigerant header 20 by tightening the screw 31 and bringing the tip of the screw 31 into contact with the coiled tube 6.

In FIG. 6, a heat insulating joint portion 2C is provided at the boundary between the double pipe portion 2 and the single pipe portion 1. The heat insulating joint portion 2C thermally shuts off the outer pipe of the single pipe portion 1 and the outer pipe 2B of the double pipe portion, and has a cross-sectional circle between the inner pipe 2A and the outer pipe 2B of the double pipe portion 2. It has a function of thermally blocking the annular region α and the hollow portion β of the single tube portion 1. In other words, the region α is closed by the heat insulating joint portion 2C, and the region α and the internal space of the single pipe portion 1 are blocked by the heat insulating joint portion 2C.
Further, since the heat insulating joint portion 2C serves as a connecting portion of the drilling rod 10, it has rigidity to transmit the drilling torque on the ground at the time of drilling.
Here, when the material of the heat insulating joint portion 2C is a metal having high thermal conductivity, for example, iron, the cold heat of the refrigerant in the frozen region (the portion of the single pipe portion 1) is conducted by the heat insulating joint portion 2C to conduct the double pipe portion. Since heat is conducted to the outer pipe 2B of 2, there is a risk that the ground of the double pipe 2 will freeze.
Therefore, in the illustrated embodiment, the heat insulating joint portion 2C is manufactured of a material having both heat insulating properties and torque rigidity (for example, MC nylon resin, polyamide resin, hard rubber, etc.).
By forming the heat insulating joint portion 2C with a heat insulating material, the cold heat of the refrigerant in the frozen region is blocked by the heat insulating joint portion 2C and is not transmitted to the outer pipe 2B. Therefore, it is possible to prevent the cold heat of the refrigerant from being transmitted to the double pipe portion 2 and freezing.

Next, a mode in which the freezing step shown in FIG. 4 is completed and the above-ground member shown in FIG. 5 is removed in order to thaw the frozen ground will be described with reference to FIGS. 5, 7 to 9.
First, in FIG. 5, the refrigerant supply to the coiled tube 6 is stopped, and the refrigerant return port 22 communicates with the region between the inner pipe 2A and the outer pipe 2B (region α in FIGS. 1, 2, and 4). Recover the refrigerant from. Then, the heat-insulated state is easily released by increasing the pressure in the region decompressed by vacuuming from the heat insulating material introduction portion 41 to atmospheric pressure or discharging the filled heat insulating gas (or heat insulating liquid). ..
Next, the refrigerant header 20 is removed before the thaw liquid is circulated.
When removing the refrigerant header 20, in FIG. 5, first, the screw 31 of the plug member P20 is loosened to release the engagement with the coiled tube 6. Then, the plug member P20 and the refrigerant header 20 are unscrewed and removed. The screw between the refrigerant header 20 and the connecting member 2AJ is released, and the refrigerant header 20 is removed from the connecting member 2AJ (state of FIG. 7).
Then, with reference to FIGS. 7 to 9, a procedure for removing the heat insulating material header 40 and the inner pipe 2A of the double pipe portion will be described.

In FIG. 7, the heat insulating material header 40 and the guide member P40 are unscrewed, and the guide member P40 is removed from the heat insulating material header 40. Then, the guide member P40 is pulled out from the connecting member 2AJ by a known means. Next, the screw of the connecting portion 40J between the heat insulating material header 40 and the outer pipe 2B of the double pipe portion is released, and the heat insulating material header 40 is removed from the ground side end of the outer pipe 2B of the double pipe portion. Remove and collect. As a result, the state shown in FIG. 8 is obtained.
From the state shown in FIG. 8, a jig (not shown) is fixed (screwed) to the ground side end of the connecting member 2AJ, and the connecting member 2AJ is pulled out to the ground side (left side in FIG. 8) using the jig.

As described above with reference to FIG. 5, since the connecting member 2AJ is screwed to the ground side end of the inner pipe 2A by the connecting portion 62, when the connecting member 2AJ is pulled out, the entire inner pipe 2A is on the ground side (FIG. 5). It is pulled out to the left of 8).
When the entire inner pipe 2A is pulled out to the ground side, the protrusion 52 and the spring 54 integrated with the inner pipe 2A by welding or the like are also pulled out (together with the inner pipe 2A).

Although not clearly shown, in the illustrated embodiment, the inner pipe 2A is also configured by screwing the standard rods (2AS) together, so that the inner pipe 2A is formed every time the rod is pulled out by a predetermined length. Unscrew the rods.
In FIG. 8, when the connecting member 2AJ, the inner pipe 2A, and the spring 54 are pulled out, only the state shown by the solid line in FIG. 9, that is, the outer pipe 2B (or single pipe) of the double pipe and the coiled tube 6 remains. Become in a state.

Further, in the illustrated embodiment, after the refrigerant is recovered and the heat insulating state of the region α is released, only the outer tube 2B and the coiled tube 6 remain as shown in FIG. Then, the thaw liquid header 60 (shown by the dotted line in FIG. 9) is screwed into the female screw F2B at the above-ground side end of the outer pipe 2B.
Thaw supplied from the coiled tube 6 by supplying a thaw liquid (the flow of which is indicated by an arrow NF) from the coiled tube 6 and discharging the thaw liquid from the thaw liquid discharge port 61 (arrow NF 8) of the thaw liquid header 60. The liquid returns to the ground side through the hollow portion in the radial direction of the outer pipe 2B of the double pipe, and the amount of heat held by the thaw liquid is not only the ground on the radial outer side of the single pipe 1 but also the outer pipe 2B. It is surely transmitted to the ground outside in the radial direction of. Therefore, even if the ground in the non-frozen region corresponding to the double pipe portion 2 in FIGS. 1, 2, and 4 is frozen, it can be reliably unfrozen with the thaw liquid.
Thawing of the ground around the freezing pipe is completed with the thawing liquid, the coiled tube 6 is pulled out, and the drilling rod 10 remaining in the ground is pulled out while being unscrewed.
The freezing pipe constituent members (including the boring head 30) that have been disassembled by releasing the screw connection after the above-mentioned freezing is completed are reused for new freezing work.

Next, the boring head 30 will be described with reference to FIGS. 10 to 12. In FIG. 10, the flow of the refrigerant is indicated by an arrow R.
In FIG. 10, the boring head 30 arranged at the underground end of the freezing pipe outer pipe 10 constitutes a single pipe connecting portion 30A on the ground side thereof. A drilling bit connection portion 30B is provided on the underground side of the boring head 30.
A male screw is formed on the single pipe connecting portion 30A of the boring head 30, and a male screw is also formed on the underground side (boring head 30 side) of the freezing pipe outer pipe 10 (single pipe portion 1). The single pipe connecting portion 30A and the single pipe portion 1 are joined via a coupling member 9. Here, the coupling member 9 is formed with a female screw (unsigned) screwed with the male screw of the boring head 30 and a female screw (unsigned) screwed with the male screw of the single tube portion 1.
A male screw (unsigned) is also formed in the drilling bit connection portion 30B, and the male screw and the female screw of the drilling bit portion 7 (female screw formed on the inner circumference of the connection portion 7C: unsigned) are screwed together. , The boring head 30 and the drilling bit portion 7 are joined.

The boring head 30 is provided with a flow path 4, and the flow path 4 extends in the vertical direction from the hollow portion of the single pipe portion 1 to the valve mechanism 3. The drilling water W flows through the flow path 4 during drilling, and the refrigerant R flows through the flow path 4 during freezing.
In FIG. 10, the coiled tube 6 is held in a state of being inserted into the coiled tube tip insertion portion 4B in the flow path 4 when frozen. In the boring head 30, a tapered region 4T having a tapered inner wall surface is formed on the ground side (upper side of FIG. 10) of the flow path 4.
As described above, after the coiled tube 6 is inserted, the drilling rod 10 functions as the freezing tube outer tube 10.

A refrigerant flow path 5 is formed in the boring head 30, and the refrigerant flow path 5 branches from the branch portion 4A of the flow path 4 to the radial refrigerant flow path 5A by bypassing the valve mechanism 3, and the vertical refrigerant flow. It communicates with the tip refrigerant passing region 5C at the tip of the drilling rod 10 via the path 5B. The tip refrigerant passage region 5C communicates with the hollow portion in the freezing pipe outer pipe 10 via the return refrigerant flow path 5D. That is, the refrigerant flow path 5 is composed of a radial refrigerant flow path 5A, a vertical refrigerant flow path 5B, a tip refrigerant passage region 5C, and a return refrigerant flow path 5D.
Here, the tip refrigerant passing region 5C is configured as a region outward in the radial direction of the spring accommodating portion 12. As will be described later, the spring accommodating portion 12 is formed in a hollow cylindrical shape, and the spring 3A of the valve mechanism 3 is accommodating therein.
The return refrigerant flow path 5D, which is a flow path on the refrigerant return side, is adjacent to the vertical refrigerant flow path 5B in the circumferential direction and extends in the vertical direction (direction orthogonal to the paper surface in FIG. 11). Four vertical refrigerant flow paths 5B and four return refrigerant flow paths 5D are alternately arranged in the circumferential direction. In other words, the tip refrigerant passage region 5C is composed of a space communicating with four vertical refrigerant passages 5B and four return refrigerant passages 5D (see FIG. 11).

The flow of the refrigerant flowing through the refrigerant flow path 5 branched from the flow path 4 will be described with reference to FIGS. 10 and 11.
In FIG. 10, the refrigerant R branched from the flow path 4 flows through the radial refrigerant flow path 5A, communicates with the vertical refrigerant flow path 5B (vertical flow path on the refrigerant supply side), and is on the underground side of the boring head 30. It reaches the tip refrigerant passage region 5C at the tip.
The refrigerant R that has reached the tip refrigerant passage region 5C flows toward the ground side in the hollow portion in the freezing pipe outer pipe 10 via the return refrigerant flow path 5D (arrow R3 in FIG. 10).

Here, the flow path cross-sectional areas of the vertical refrigerant flow path 5B, the tip refrigerant passage region 5C, and the return refrigerant flow path 5D are the cross-sectional areas of the regions between the inner wall of the drilling rod 10 and the coiled tube 6 (arrows). It is smaller than the area where the refrigerant flows indicated by R3). Therefore, the flow velocity of the refrigerant R flowing through the vertical refrigerant flow path 5B, the tip refrigerant passage region 5C, and the return refrigerant flow path 5D is about the same as or higher than the flow velocity of the refrigerant indicated by the arrow R3.
In general, it is known that when a refrigerant flows through a flow path, a turbulent flow having a faster flow than a laminar flow is superior in heat mobility (heat transfer coefficient). In the illustrated embodiment, as described above, the flow velocity of the refrigerant R flowing through the vertical refrigerant flow path 5B, the tip refrigerant passage region 5C, and the return refrigerant flow path 5D is faster than the flow velocity of the refrigerant R indicated by the arrow R3. Excellent thermal mobility.
Therefore, the ground freezing effect of the refrigerant R flowing through the vertical refrigerant flow path 5B, the tip refrigerant passage region 5C, and the return refrigerant flow path 5D is due to the refrigerant flowing in the region between the inner wall of the drilling rod 10 and the coiled tube 6. It is as effective as the ground freezing effect of R.

In FIGS. 10 and 11, the radial refrigerant flow path 5A extends in the horizontal direction, but can be extended downward (extended diagonally downward) as it goes outward in the radial direction. be. Here, it is inconvenient that the radial refrigerant flow path 5A extends upward (extends diagonally upward) as it goes outward in the radial direction because the resistance of the refrigerant R increases. However, if the cold heat of the refrigerant R is transmitted to the tip of the boring head 30 (underground side end: lower end) and the vicinity of the tip of the boring head 30 can be sufficiently frozen, the radial refrigerant flow The road 5A may extend diagonally upward.

In FIG. 10, the valve mechanism 3 is provided at a position where the lower end of the flow path 4 communicates with the boring head 30. In the state shown in FIG. 10 (when frozen), the valve body 3B is seated on the valve seat 3C due to the elastic repulsive force of the spring 3A. This is because the elastic repulsive force of the spring 3A is weaker than the pressure of the drilling water W at the time of drilling the boring hole and is adjusted to be stronger than the supply pressure of the refrigerant R at the time of freezing.
Therefore, when the drilling water W is supplied at the time of drilling a boring hole, the pressure of the drilling water W is stronger than the elastic repulsive force of the spring 3A, so that the valve body 3B has the elastic repulsive force of the spring 3A. It is pressed downward against it, the valve body 3B does not sit on the valve seat 3C, and the valve mechanism 3 opens.
On the other hand, at the time of freezing, the supply pressure of the refrigerant R is weaker than the elastic repulsive force of the spring 3A, so that the valve body 3B is pressed upward by the elastic repulsive force of the spring 3A and sits on the valve seat 3C. 3 is obstructed.

As described above, the spring 3A of the valve mechanism 3 is housed in the hollow cylindrical spring storage portion 12. The spring accommodating portion 12 is made of a material (material is not particularly limited) that does not allow the refrigerant to permeate, and the refrigerant R flowing through the tip refrigerant passing region 5C passes through the region outside the side surface of the spring accommodating portion 12. It does not come into contact with the spring 3A. The inside of the spring storage portion 12 in the radial direction is a spring 3A storage space.
A drilling water injection port 7B is formed at the center of the bit tip portion 7A (see FIG. 12) of the drilling bit portion 7 arranged at the bottom portion (underground side end portion) of the boring head 30.

The drilling bit portion 7 is made of steel having excellent thermal conductivity, and the cold heat of the refrigerant R flowing through the tip refrigerant passing region 5C can be efficiently transferred to the ground G.
In FIG. 12 showing the end face shape of the drilling bit portion 7, the bit tip portion 7A (the portion located at the tip of the drilling rod 10 on the underground side) of the drilling bit portion 7 has a disk shape and is on the ground G side (ground). On the surface (on the middle side), a plurality of chips 7D (six in the embodiment) protruding toward the ground G side are provided at equal intervals in the circumferential direction. As described above, an injection port 7B for injecting the drilling water W into the ground is formed at the center of the bit tip portion 7A of the drilling bit portion 7.
The thickness dimension of the bit tip portion 7A of the drilling bit portion 7 (dimension D in FIG. 10) is a dimension in which the cold heat of the refrigerant is conducted and has a strength capable of withstanding use during drilling.

In FIG. 10, the refrigerant R is supplied from the coiled tube 6 to the flow path 4 of the boring head 30, passes through the flow path 4, and reaches the valve mechanism 3. As described above, since the supply pressure of the refrigerant R is smaller than the elastic repulsive force of the spring 3A, the valve mechanism 3 remains closed and the refrigerant R cannot pass through the valve mechanism 3.
The refrigerant R bypasses the valve mechanism 3 and passes through the radial refrigerant flow path 5A and the vertical refrigerant flow path 5B branched from the branch portion 4A of the flow path 4, and the tip of the freezing pipe tip (tip of the boring head 30). It reaches the refrigerant passage region 5C. The cold heat of the refrigerant R that has reached the tip refrigerant passage region 5C is input (transmitted) to the ground G via the drilling bit portion 7, and freezes the ground in the region near the tip of the freezing pipe.
The refrigerant R that has reached the refrigerant passage region 5C at the tip of the boring head 30 flows through the return refrigerant flow path 5D that communicates with the refrigerant passage region 5C at the tip, and is an outer pipe of the freezing pipe as shown by arrows R3 and R4. It passes through the internal space of the single pipe portion 1 of 10 and the internal space of the inner pipe 2A of the double pipe portion 2 and returns to the ground side (see FIGS. 10 and 4).

According to the mechanism shown in FIGS. 10 to 12, since the refrigerant flow path 5 for reaching the refrigerant R is formed at the tip of the freezing pipe, freezing to the most advanced portion (the most advanced portion on the underground side) of the refrigerant R is possible. It is possible. That is, the refrigerant R can be sent to the region ahead of the valve mechanism 3 (underground side) to freeze the region near the tip of the freezing pipe.
For example, when a shield machine approaches a shaft and the area between the shaft and the tip of the shield machine should be frozen, in the illustrated embodiment, a portion of the shaft wall is drilled and frozen as in the prior art. There is no need to place a tube. According to the illustrated embodiment, if the freezing pipe is arranged near the shaft, the area between the shield machine and the shaft can be frozen.
In other words, in the illustrated embodiment, the freezing pipe does not need to drill a portion of the shaft wall as the shield machine approaches the shaft and freezes between the shaft and the tip of the shield machine. Therefore, the wall of the shaft will not be damaged.

According to the illustrated embodiment, since the installation of the freezing pipe outer pipe 10 is completed at the same time as the drilling of the boring hole is completed, it is possible to omit a plurality of steps of inserting the freezing pipe and pulling out the drilling rod.
In addition, the drilling rod can be used repeatedly, and various depths can be supported by combining standard length rods. As a result, the cost and labor of the freezing method can be reduced. Furthermore, since a drilling rod that maintains airtightness when connected is used, it is possible to omit on-site leak inspection.

According to the illustrated embodiment, the region α having an annular cross section between the inner pipe 2A and the outer pipe 2B of the double pipe portion 2 of the freezing pipe outer pipe 10 (drilling rod 10) is, for example, vacuumed at the time of limited freezing. Since the pressure is reduced by pulling or filled with a heat insulating gas (or heat insulating liquid), the region α has high heat insulating properties, and the cold heat of the refrigerant R flowing inside the inner pipe 2A of the double pipe portion 2 is blocked in the region α. Therefore, heat is not transferred to the ground near the double pipe portion 2 of the freezing pipe outer pipe 10. Therefore, the ground near the double pipe portion 2 of the limited freezing tube 10 does not freeze.
The work of decompressing by vacuuming or filling with a heat insulating gas (or heat insulating liquid) is much easier than the work of wrapping a heat insulating material around the outer circumference of the inner pipe in the prior art, and the workability is good. .. That is, according to the illustrated embodiment, the limited freezing can be easily performed as compared with the prior art.
Then, according to the illustrated embodiment, the depth of the boundary between the frozen region and the non-frozen region is such that the positions of the single pipe portion 1 and the double pipe portion 2 in the frozen pipe outer pipe 10 (drilling rod 10) are appropriately changed. Can be set freely.

Further, according to the illustrated embodiment, the highly airtight drilling rod 10 is used as the freezing tube outer tube 10, and when the freezing tube is removed, the rods having a unit length of the drilling rod 10 are connected to each other. Since the part (the part to be screwed with the male screw and the female screw) is pulled out to the ground side while being unscrewed, the rod having a unit length after the unscrew can be reused.
When the drilling rod 10 used as the freezing pipe outer pipe 10 is pulled out, it is not necessary to cut gas or the like as in the freezing pipe pulling-out work in the prior art, and it is not necessary to use a firearm. Therefore, the safety and environmental protection of the freezing pipe removal work are improved.

Further, according to the illustrated embodiment, since the valve structure 3 of the type in which the valve body 3B is seated on the valve seat 3C by the elastic repulsive force of the spring 3A is adopted, the valve is opened at the time of drilling the boring hole. The operation of closing the valve during the freezing operation is automatically performed by appropriately adjusting the pressures of the drilled water W and the refrigerant R and the elastic modulus of the spring, and no special valve opening / closing operation is required.
Further, according to the illustrated embodiment, when the outer pipe 10 of the freezing pipe is pulled out, a filler (a landfill material for filling the boring hole) can be discharged from the tip to perform landfilling, so that the freezing pipe 10 is used. It is easy to fill in the holes after pulling out. In this case, at the same time as drilling, the valve mechanism 3 is opened by the discharge pressure of the filler, and the filler is discharged from the injection port 7B into the drilling space.
In addition, in the illustrated embodiment, since the refrigerant supply pipe 6 is composed of a coiled tube that does not need to be cut and spliced, the refrigerant supply pipe 6 can be easily pulled out to the ground side.
Then, by easily pulling out the refrigerant supply pipe 6 to the ground side, additional drilling of the boring hole can be easily performed by using the drilling rod constituting the outermost pipe in the radial direction of the freezing pipe 100. Can be done.

Further, in the illustrated embodiment, the inner pipe 2A is urged downward in the vertical direction by the protrusion 52 and the coil spring 54 fixed to the inner pipe 2A of the double pipe portion 2, and the inner pipe 2A is thermally contracted to the ground side. Since it is suppressed from being pulled by, the force that the inner pipe 2A is pulled up to the ground side by heat shrinkage is canceled out, and the shearing force acting on the O ring 25 in the lowermost inner pipe 2A is suppressed. NS. Therefore, deterioration of the sealing performance of the O-ring 25 of the lowermost inner pipe 2A is prevented.
Further, in the illustrated embodiment, the heat insulating joint portion 2C is provided at the boundary portion between the double pipe portion 2 and the single pipe portion 1, and the heat insulating joint portion 2C is made of a heat insulating material such as MC nylon resin, polyamide resin, or hard rubber. Since it is configured, it is prevented that the cold heat of the refrigerant R is transmitted to the outer pipe 2B, and the ground of the double pipe portion 2 is also prevented from freezing.

In the illustrated embodiment, the refrigerant header 20 and the heat insulating material header 40 are removed at the time of thawing, the inner pipe 2A is removed to leave only the outer pipe 2B and the coiled tube 6, and the thawing liquid header 60 is attached to the outer pipe 2B. If the thawing liquid is supplied from the coiled tube 6 and the thawing liquid is discharged from the thawing liquid header 60, the amount of heat possessed by the thawing liquid is not only in the ground on the radial outer side of the single tube 1 but also through the outer tube 2B. It is also transmitted to the ground outside in the radial direction. Therefore, even if the ground of the double pipe portion 2 freezes, it can be surely unfrozen with the thawing liquid.

It should be added that the illustrated embodiment is merely an example and is not a description intended to limit the technical scope of the present invention.

1 ... Single tube (single tube part)
2 ... Double pipe (double pipe part)
2A ・ ・ ・ Inner pipe 2B ・ ・ ・ Outer pipe 2C ・ ・ ・ Insulation joint part 3 ・ ・ ・ Valve mechanism 3A ・ ・ ・ Spring 3B ・ ・ ・ Valve body 3C ・ ・ ・ Valve seat 4 ・ ・ ・ Flow path 5 ・・ ・ Refrigerant flow path 6 ・ ・ ・ Refrigerant supply pipe (coiled tube)
10 ... Drilling rod (freezing pipe outer pipe)
11 ... Low temperature shrinkage leakage prevention device 30 ... Boring head 100 ... Freezing pipe R ... Refrigerant W ... Drilling water α ... Circular cross section

Claims (8)

It has a boring head that is screwed and connected to the tip, and a plurality of drilling rods that have sealing performance at the connection point and are screwed and connected.
It has a seamless refrigerant supply pipe that is inserted into the drilling rod.
The drilling rod functions as a freezing pipe outer pipe after the refrigerant supply pipe is inserted.
It is composed of a refrigerant header that is removable from the freezing pipe outer pipe and communicates with the region between the freezing pipe outer pipe and the refrigerant supply pipe.
The components of the freezing tube can be connected or assembled by screwing and disassembled into the members by unscrewing .
The boring head at the tip of the drilling rod is provided with a valve mechanism that opens at the pressure of the drilling water but closes at the supply pressure of the refrigerant, and extends in the axial direction of the freezing pipe and drills. A freezing pipe characterized in that a refrigerant flow path is formed that branches from the axial flow path through which the perforated water and the refrigerant flow, bypasses the valve mechanism, and supplies the refrigerant to the tip of the freezing pipe. In the case of limited freezing, an inner pipe having a sealing performance at the connection point and screwed is arranged inside the freezing pipe outer pipe, and a double pipe portion having a heat insulating layer and a single pipe having no heat insulating layer are arranged. A part is formed, and the inner pipe is provided with a mechanism for urging downward in the pipe axis direction.
At the boundary between the double pipe and the single pipe, a heat insulating joint is made of a material that has both rigidity to transmit drilling torque at the time of drilling and heat insulation in the pipe axis direction, and both ends are screwed to the outer pipe of the freezing pipe. The freezing tube according to claim 1, wherein the freezing tube is detachable from the outer tube of the freezing tube and has a header for a heat insulating material communicating with the region between the inner tube and the outer tube of the double tube portion. .. It has a boring head that is screwed and connected to the tip, and the connection point has sealing performance. Using multiple drilling rods that are screwed and connected, the boring hole is drilled while injecting drilling water. The boring head at the tip of the rod is provided with a valve mechanism that opens at the pressure of the drilled water but closes at the supply pressure of the refrigerant.
After drilling a boring hole, the drilling rod remains on the ground to be frozen,
A seamless refrigerant supply pipe is inserted into the drilling rod, and the drilling rod functions as a freezing pipe outer pipe after the refrigerant supply pipe is inserted.
The refrigerant is supplied from the refrigerant supply pipe, and the refrigerant bypasses the valve mechanism and reaches the tip of the drilling rod through the axial pipe extending in the axial direction of the freezing pipe and the refrigerant flow path. The refrigerant is discharged from the refrigerant header that is detachable from the freezing pipe outer pipe and communicates with the region between the freezing pipe outer pipe and the refrigerant supply pipe through the region between the refrigerant supply pipes. A freezing method characterized by. In the case of limited freezing, the connection portion forming the heat insulating space with the drilling rod inside the drilling rod has a sealing performance, and the double pipe portion and the heat insulating layer having a heat insulating layer by the screw-connected inner pipe. The inner pipe is provided with a mechanism for urging downward in the pipe axial direction.
At the boundary between the double pipe portion and the single pipe portion, a heat insulating joint portion in which both ends are screwed and connected to the drilling rod with a material having both rigidity for transmitting drilling torque at the time of drilling and heat insulating property in the pipe axis direction. And, it has a heat insulating material header that is removable from the freezing pipe outer pipe and communicates with the area between the inner pipe and the outer pipe of the double pipe portion, and the heat insulating space is lowered by the heat insulating material header. The freezing method according to claim 3 , which insulates heat by applying pressure. In the case of limited freezing, the connection portion forming the heat insulating space with the drilling rod inside the drilling rod has a sealing performance, and the double pipe portion and the heat insulating layer having a heat insulating layer by the screw-connected inner pipe. The inner pipe is provided with a mechanism for urging downward in the pipe axial direction.
At the boundary between the double pipe portion and the single pipe portion, a heat insulating joint portion in which both ends are screwed to the drilling rod with a material having both rigidity to transmit drilling torque at the time of drilling and heat insulation in the pipe axis direction. And, it has a heat insulating material header that is removable from the freezing pipe outer pipe and communicates with the area between the inner pipe and the outer pipe of the double pipe portion, and the heat insulating material header insulates the heat insulating space. The freezing method according to claim 3 , wherein heat is insulated by filling with a fluid. In the case of limited freezing, the connection portion forming the heat insulating space with the drilling rod inside the drilling rod has a sealing performance, and the double pipe portion and the heat insulating layer having a heat insulating layer by the screw-connected inner pipe. The inner pipe is provided with a mechanism for urging downward in the pipe axial direction.
At the boundary between the double pipe portion and the single pipe portion, a heat insulating joint portion in which both ends are screwed and connected to the drilling rod with a material having both rigidity for transmitting drilling torque at the time of drilling and heat insulating property in the pipe axis direction. And, it has a heat insulating material header that is removable from the freezing pipe outer pipe and communicates with the area between the inner pipe and the outer pipe of the double pipe portion, and the heat insulating material header insulates the heat insulating space. The freezing method according to claim 3 , which insulates heat by installing a material. At the time of thawing, the refrigerant header and the heat insulating material header are removed, and the inner pipe is removed to leave the drilling rod and the refrigerant supply pipe.
Attach a removable defrosting liquid header to the drilling rod,
The freezing method according to any one of claims 3 to 6 , wherein the thawed liquid is supplied from the refrigerant supply pipe, discharged from the thawed liquid header, and the periphery of the freezing pipe is thawed. The freezing method according to any one of claims 3 to 7 , wherein the freezing pipe constituent member is reused for new freezing by releasing the screw connection.

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