JP2018178529A - Freezing pipe and freezing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a freezing pipe and a freezing method which can freeze to the region of the tip of the freezing pipe without welding the freezing pipes to each other.SOLUTION: In the present invention, a boring hole is drilled while injecting drilling water (W) by using a drilling rod (10) composed of a plurality of rods, a drilling water flow path (4) and a coolant flow path (5) are switched by a valve mechanism (3) provided near the tip of the drilling rod (10), the drilling rod (10) remains on the ground to be frozen, a seamless coolant supply pipe (6) is inserted into the drilling rod (10), after the coolant supply pipe (6) is inserted, the drilling rod (10) functions as a freezing pipe (10), and supplies the coolant (R) from the coolant supply pipe (6), and the supplied coolant (R) is supplied to the tip of the freezing pipe (10).SELECTED DRAWING: Figure 3

Description

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

In the conventional freezing method, the boring rod for the freezing pipe is bored by the boring rod. Thereafter, a double pipe freezing pipe is built, the drilling rod is pulled out, and an air leakage test (a refrigerant leakage test) is performed to confirm that the refrigerant does not leak, and then the refrigerant is supplied.
Here, after drilling by a double pipe, there is a technique of supplying brine from the inner pipe of the double pipe and flowing it out into the outer pipe (for example, Patent Document 1), but the mechanism for switching between cutting water and refrigerant is The inner pipe slides upward, and the refrigerant can not be supplied to the tip side of the inner pipe. Therefore, it was not possible to freeze the ground around the tip of the freezing tube. Since the ground around the tip can not be frozen, in the prior art, in order to freeze the required length, an extra hole has to be drilled accordingly.
For example, in order to freeze the area between the shaft and the tip of the shield machine when the shield machine approaches the shaft, when placing a freeze pipe and performing the freezing method, it is possible to freeze the area of the freeze pipe tip Because it was not, it was necessary to make an extra hole by that amount, and it was necessary to drill a part of the wall of the shaft so that the freezing pipe was inserted into the part of the wall. For this reason, it is necessary to carry out a large work of drilling a part of the wall of the shaft, and there is a problem that the wall of the shaft is damaged.

In addition, in the prior art, in order to prevent the leakage of the refrigerant, in the prior art, in order to prevent the leakage of the refrigerant, the pipes constituting the freezing pipe are welded all around at every joint portion of 5.5 m in length.
However, in the work of welding the freeze pipes together, airtightness is required in the welded portion in order to prevent the refrigerant from leaking, and a great deal of labor is required.
Furthermore, when the freezing process is completed and the freezing tube is removed, a special filling tube is inserted into the hole (punch hole space) of the freezing tube trace created after pulling out the whole freezing tube, and the filling material is filled, It is necessary to fill the holes to prevent the settlement of the surrounding ground and so on, and it is necessary to do so. And, there is a difference in time between the extraction and filling of the freezing tube, and there is a problem such as the increase of the settlement during that time.
Although there is a demand to reduce the various labors mentioned above and to reduce the cost of the entire freezing method, a technique to meet such a demand has not been proposed yet.

Patent No. 3681363

  The present invention has been proposed in view of the problems of the prior art described above, and by supplying a refrigerant to the tip of the freezing tube, a frozen soil region can be formed up to the tip of the tip, and the freezing tubes are welded with joints. The purpose is to provide a freezing pipe and a freezing method that do not need to be joined.

The freezing pipe of the present invention comprises a plurality of rods (for example, a fixed length rod of unit length), and a drilling rod (10) for drilling a boring hole while spraying drilling water (W);
Having a refrigerant supply pipe (6: for example a coiled tube) inserted in the drilling rod (10);
In the vicinity of the tip of the drilling rod (10), it is opened by the water pressure of drilling water (W) but closed by the supply pressure of the refrigerant (R) (pressure just above the valve body 3B at the time of refrigerant supply) A valve mechanism (3) is provided and branched from a pipe (4) through which drilling water (W) flows to bypass the valve mechanism (3) and supply refrigerant (R) from the ground to the tip of the drilling rod (10) A refrigerant channel (5) is formed, and the refrigerant (R) is characterized by freezing the ground by circulating on the ground and in the ground.

In the freeze pipe according to the present invention, the valve mechanism (3) includes a valve seat (3C) and a valve body (3B) biased in a direction of seating on the valve seat (3C) by elastic repulsive force of a spring (3A). And the spring (3A) has a lower resilience than the pressure of the drilling water, and is adjusted to be stronger than the supply pressure of the refrigerant (the pressure immediately above the valve body 3B).
The freezing pipe of the present invention can be put into a single pipe state by pulling out the refrigerant supply pipe at the end of freezing and pulling out the removal of the freezing pipe, and discharging the filling material from the tip of the drilling rod It can have a function to backfill the drilling space.

In the freezing method of the present invention, the boring hole is bored while spraying the boring water (W) using the boring rod (10) composed of a plurality of rods (for example, a fixed length rod of unit length) ,
Remain in the ground where the drilling rod (10) should be frozen,
After the refrigerant supply pipe (6: coiled tube, for example) is inserted into the drilling rod (10) and the refrigerant supply pipe (6) is inserted, the drilling rod (10) functions as a freezing pipe (10),
Switch the drilling water channel (4) and the coolant channel (5) by the valve mechanism (3) provided near the tip of the drilling rod (10),
The refrigerant (R) is supplied from the refrigerant supply pipe (6), and the supplied refrigerant (R) is supplied to the tip of the freezing pipe.
In the freezing method of the present invention, it is possible to make the drilling rod into a single tube state by pulling out the refrigerant supply pipe at the end of freezing and pulling out the freezing pipe removal, and discharging the filling material from the tip of the drilling rod It is possible to backfill the drilling space.

  In the freezing method of the present invention, the valve mechanism (3) has the valve body (3B) seated on the valve seat (3C) by the elastic repulsive force of the spring (3A), and the elastic repulsion of the spring (3A) The force is weaker than the pressure of the drilling water (W) (during boring) and is adjusted stronger than the supply pressure of the refrigerant (R) (pressure immediately above the valve 3 B at the time of refrigerant supply).

And, in the present invention, the refrigerant supply pipe (6) is preferably constituted by a seamless piping material or tube material, for example, a coiled tube which does not need to be spliced.
Furthermore, in the present invention, it is preferable that an external thread is formed at one end of a rod (fixed-size rod) of a unit length constituting the drilling rod (10) and an internal thread is formed at the other end.

In the present invention, the refrigerant may be brine or liquefied carbon dioxide (CO ₂ ), and there is no particular limitation.
Here, a refrigerant cooling facility is provided on the ground side. For example, when using liquefied carbon dioxide as the refrigerant, the refrigerant cooling facility on the ground side is discharged from the freezing pipe (10) so that the refrigerant deprives the heat of vaporization from within the ground. It is preferable to configure as a circulating cooling mechanism that cools the gas-liquid mixed carbon dioxide into liquid phase and supplies the carbon dioxide of liquid phase to the freezing pipe (10). Also in the case where the refrigerant is brine, it is preferable to use a circulating cooling mechanism that cools the brine discharged from the freeze tube (10) and supplies it to the freeze tube (10).

According to the present invention having the above-described configuration, the refrigerant flow path (5) for supplying the refrigerant (R) is formed at the tip of the freezing pipe (10). R) can reach and freeze it by injecting cold heat into the ground region in the extension direction of the freezing tube (10) rather than the tip of the freezing tube (10).
Therefore, for example, in order to freeze the region between the shaft and the tip of the shield machine when the shield machine approaches the shaft, when the freezing tube is arranged and the freezing method is carried out, the tip of the freeze tube is advanced. 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, it is not necessary to drill a part of the wall of the shaft when placing the freezing pipe, and the wall of the shaft will not be damaged.

And according to the present invention, the drilling rod (10) used for drilling the borehole and as the freezing tube outer pipe screw-joins and separates a rod (a fixed length rod) of unit length. Therefore, it is possible to use repeatedly and it is possible to cope with various construction depths by appropriately combining rods of unit length. And since it is not necessary to manufacture the pipe | tube for drilling of special length with respect to various installation depths, the cost of a freezing construction method can be reduced.
Here, as a rod of a unit length (a fixed-sized rod), a rod that maintains airtightness when connected is used, so it is possible to omit a leak inspection at a construction site.
Here, in the present invention, since the single pipe portion (1) of the drilling rod (10) functions as the outer tube of the freezing tube, the installation of the freezing outer tube is completed simultaneously with the completion of drilling of the borehole.

  In the present invention, when the valve mechanism (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), If the pressure of W) is stronger than the spring repulsion, and the supply pressure of the refrigerant (R) (pressure immediately above the valve body 3B at the time of refrigerant supply) is adjusted to be weaker than the spring repulsion, drilling water (W) is adjusted. ) Is discharged and closed automatically during freezing operation, and no special operation is required.

Further, according to the present invention, at the time of removing the freeze pipe, it is sufficient to release the screwing of the rod of unit length, there is no need to perform gas cutting or the like, and the use of firearms is unnecessary. Therefore, the safety of the freezing pipe removal work is improved. Also, since no firearms are used, it contributes to environmental protection.
And according to the present invention, since it is possible to discharge the filling material (filling material for filling the borehole) from the tip when drawing out the freezing pipe, filling the hole in the drilling space simultaneously with drawing out the freezing pipe It is possible to prevent the collapse and settlement of the thawed surrounding ground, and the filling operation is easy.

Further, according to the present invention, if the coiled tube does not need to be connected, the refrigerant supply pipe can be easily pulled out to the ground side.
Then, the refrigerant supply pipe can be easily pulled out to the ground side, so that it is possible to easily carry out the additional drilling of the borehole using the drilling rod that constitutes the freezing outer tube.

It is sectional drawing which shows the process of drilling a borehole in embodiment of this invention. In embodiment, it is sectional drawing which shows the process of inserting piping for refrigerant | coolant supply. In embodiment, it is sectional drawing which shows the process of supplying a refrigerant and freezing a ground. It is a partial cross-sectional enlarged view which shows the underground side front-end | tip of the freezing pipe | tube used by embodiment. It is AA sectional drawing in FIG. It is an end view in the B arrow direction in FIG. 4, and is a figure for demonstrating the discharge port of the drilling bit and drilling water provided in the underground side front-end | tip of the freezing pipe used by embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
In FIG. 1 which shows the process of drilling a boring hole in the ground G, the drilling rod 10 is comprised by a single pipe.
Although not clearly illustrated, the drilling rod 10 is configured by, for example, connecting (connecting) a plurality of rods of a unit length (scale rods). The fixed rod (rod of unit length) has an external thread (not shown) formed at one end, and an internal thread (not shown) formed at the other end, and the external thread and the internal thread are screwed together The fixed rods can be connected to each other to cope with various construction conditions. In addition, not only the rod size but also a relatively short rod for adjusting the length according to the required depth or the like is used.
Here, the screwed portion of the fixed size rods in the drilling rod 10 has high airtightness and water tightness so that the refrigerant does not leak when the drilling rod 10 is reused as a freezing pipe, for example, A plurality of (for example, two or more) O-rings are fitted on the male screw.

The water pressure of the drilling water W opens at the drilling end (underground) end of the drilling rod 10 (single tube), but the supply pressure of the refrigerant R (pressure immediately above the valve body 3B at the time of refrigerant supply) A valve mechanism 3 which is closed is provided, and a drilling bit portion 7 (FIGS. 4 and 6) is disposed at the tip of the drilling side (ground side) of the drilling rod 10. Further, the hollow portion of the drilling rod 10 constitutes a flow passage of drilling water W, and a guide portion 1A is provided in the vicinity of the tip when the refrigerant supply pipe 6 (coiled tube; see FIG. 2) is inserted. The guide portion 1A also functions as a flow path through which the drilling water W flows.
The valve mechanism 3 includes a spring 3A (FIG. 4), a spherical valve body 3B (FIG. 4) and a valve seat 3C (FIG. 4), the details of which will be described later. Further, the drilling bit portion 7 disposed at the tip end (underground side end portion) of the drilling rod 10 and in which the injection port 7B is formed will also be described later with reference to FIGS. 4 and 6.

In FIG. 1, at the time of drilling, the hollow portion of the drilling rod 10 constitutes a flow path of the drilling water W.
At the time of 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 drilling water W from the tip of the drilling rod 10.
The drilling water W is supplied from a not-shown water source on the ground side, passes through the hollow portion of the drilling rod 10, and is supplied to the tip (ground end) of the drilling rod 10 (arrow W1) . When the drilling water W reaches the valve mechanism 3, the valve mechanism 3 is opened against the elastic repulsive force of the spring 3 A of the valve mechanism 3. Then, the drilling water W is discharged to the ground from the injection port 7B (see FIGS. 4 and 6) formed in the drilling bit portion 7 disposed at the tip of the drilling rod 10 (arrow W2).
The discharged drilling water W travels along the outer wall of the drilling rod 10 and returns to the ground side (arrow W3).

After drilling a boring hole in the ground G by the drilling rod 10, the drilling rod 10 is left as it is in the ground G to be frozen. The remaining drilling rod 10 acts as a freezing pipe in the step of freezing the ground G.
In other words, after drilling a predetermined borehole, the drilled rod 10 becomes the frozen tube 10 when the coiled tube 6 is inserted (see FIG. 2). In the illustrated embodiment, the drilling rod and the outer tube of the freezing tube are both indicated at 10.
In the prior art, although the freezing pipe is inserted after the drilling of the borehole and the multiple steps of pulling out the drilling rod are performed, the multiple steps become unnecessary in the illustrated embodiment for the reason described above.

In the process shown in FIG. 2, the seamless coiled tube 6 is inserted into the bored rod 10. In the illustrated embodiment, after the coiled tube which is the refrigerant supply pipe is inserted, the drilling rod becomes a freezing pipe. That is, although the code | symbol 10 shows a drilling rod before the process shown in FIG. 2, the code | symbol 10 shows a freezing pipe after the process shown in FIG.
Since the coiled tube 6 is seamless and long, there is no need to cut and insert it in the ground, and there is no risk of the refrigerant leaking, so it can be arranged easily.
In the illustrated embodiment, the refrigerant may be brine or liquefied carbon dioxide (CO ₂ ), and there is no particular limitation. Although not specified, a refrigerant cooling system is provided on the ground side. For example, when carbon dioxide is used as the refrigerant, the refrigerant cooling system on the ground side is connected to the freezing pipe 10 so that the refrigerant deprives the ground of evaporation heat. It is configured as a circulating cooling mechanism that cools the discharged gas-liquid mixed carbon dioxide and supplies it to the freezing pipe 10 as a liquid phase. When the refrigerant is brine, the brine discharged from the freeze tube 10 is similarly cooled and configured as a circulating cooling mechanism to be supplied to the freeze tube 10.

The coiled tube 6 inserted inside the freezing tube 10 passes through the hollow portion of the freezing tube 10 and is inserted to the vicinity of the tip of the freezing tube 10 and the coiled tube tip difference in front of the valve mechanism 3 (ground side) It is inserted into the insertion portion 4B (see FIG. 4) and held.
As shown in FIG. 2, the freeze tube 10 has a structure similar to that of a double tube in a state where the coiled tube 6 is inserted.

As shown in FIG. 4, 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 10 is arranged horizontally or upward.
Although the illustrated embodiment illustrates the case where the ground is bored and the ground is frozen, there is no restriction as to the installation direction of the freezing pipe 10 as described above. Shells, earth anchors, concrete structures, etc. can also be drilled and frozen.

In FIG. 3 showing a state in which the freezing operation is performed, the freezing pipe 10 is in communication with the refrigerant introducing portion 21.
The refrigerant introduction portion 21 is provided with a coiled tube insertion portion 21A into which the coiled tube 6 is inserted and a refrigerant return port 21B, and the piping from the refrigerant feed port of the refrigerator (not shown) is a refrigerant feed pump The refrigerant return port 21B is connected to the coiled tube 6 via (not shown), and is connected to a refrigerant return flow path (not shown) on the ground.

In FIG. 3, the supplied refrigerant R passes through the inside of the coiled tube 6 (arrow R 1) and reaches near the underground end of the freezing tube 10.
In the vicinity of the underground end of the freezing pipe 10, the refrigerant R does not open the valve mechanism 3 (arrow R2) and flows through the tip of the drilling rod 10, and then the inner wall of the drilling rod 10 and the coiled tube Flow through the space between 6 (arrow R3). Here, as indicated by the arrow R2, the refrigerant flows through the tip of the freezing tube 10, the details of which will be described later with reference to FIG.
The refrigerant R (arrow R3) flowing through the hollow portion of the drilling rod 10 is returned from the refrigerant return port 21B to the refrigerant return flow path (not shown) on the ground (arrow R4).
When flowing through the freezing pipe 10, the cold heat of the refrigerant R is transmitted to the ground in the vicinity of the freezing pipe 10, and the ground in the vicinity of the freezing pipe 10 is frozen.

The distal end side member 30 (FIGS. 3 and 4) at the distal end portion of the freezing tube 10 has a function of connecting the drilling rod (freezing tube) 10 and the drilling bit portion 7. Here, a refrigerant flow path 5 through which the refrigerant R flows is formed in the tip end side member 30.
Details of the distal end side member 30 will be described with reference to FIGS. 4, 5 and 6. In FIG. 4, the flow of the refrigerant is indicated by an arrow R.
In FIG. 4, the ground side of the tip side member 30 disposed at the underground end of the freezing pipe 10 constitutes a drilling rod connecting portion 30A. A drill bit connection portion 30B is provided on the ground side of the tip end side member 30.

An external thread is formed in the hole-piercing rod connecting portion 30A of the distal end side member 30, and an external thread is also formed in the ground side (the distal end side member 30 side) of the freezing pipe 10. The drill rod connecting portion 30A and the underground side of the drill rod 10 are joined via the coupling member 23. Here, the coupling member 23 is formed with a female screw screwed with the male screw of the distal end side member 30 and a female screw screwed with the male screw of the drilling rod 10.
A male screw is also formed on the drill bit connection portion 30B, and the male screw and the female screw of the drill bit 7 (female screw formed on the inner periphery of the connection portion 7C) are screwed together to form the tip end side. The member 30 and the drill bit 7 are joined.

A pipe 4 is provided in the front end side member 30, and a tapered region 4T in which an inner wall surface is formed in a tapered shape is formed in the pipe 4. A large internal diameter is cut through the tapered region 4T. The hollow portion of the hole rod 10 is in communication with the portion near the coiled tube tip insertion portion 4B having a small inner diameter. The pipe 4 extends in the vertical direction from the hollow portion of the drilling rod 10 to the valve mechanism 3. In the pipe 4, drilling water W flows at the time of drilling, and refrigerant R flows at the time of freezing.
In FIG. 4, at the time of freezing, the coiled tube 6 is held in the state of being inserted into the coiled tube distal end insertion portion 4 </ b> B in the pipe 4.

A refrigerant flow path 5 is formed in the front end side member 30, and the refrigerant flow path 5 bypasses the valve mechanism 3 from the branch portion 4A of the pipe 4 and branches to the radial direction refrigerant flow path 5A. It communicates with the tip end portion refrigerant passage area 5C at the tip end of the drilling rod 10 via the path 5B. The leading end refrigerant passage area 5C is in communication with the hollow portion in the freezing pipe 10 through the return refrigerant flow path 5D.
In other words, the refrigerant flow path 5 includes the radial direction refrigerant flow path 5A, the vertical direction refrigerant flow path 5B, the tip portion refrigerant passage area 5C, and the return refrigerant flow path 5D.

A plurality of (four in the illustrated embodiment) radial coolant passages 5A extend from the branch 4A of the pipe 4 in the radial direction, and a vertical coolant passage 5B is a radial coolant passage 5A. A plurality of (four in the illustrated embodiment) extend continuously in the vertical direction.
The leading end refrigerant passage area 5C is formed to surround the valve mechanism 3 in the vicinity of the bottom end on the ground side of the leading end side member 30 (in the vicinity of the drilling bit portion 7) in communication with the vertical refrigerant passage 5B. The spring housing 12 is configured as a radially outward region of the spring housing 12 and has a hollow cylindrical shape. The foremost end of the end portion refrigerant passage region 5C is in contact with the inner surface 7AS of the bit end portion 7A. Further, the spring storage portion 12 stores the spring 3A of the valve mechanism 3 therein.
A plurality of return refrigerant flow channels 5D extend in the vertical direction in communication with the front end portion refrigerant passage area 5C, and a plurality of (four in the embodiment) are formed radially outward. The four vertical refrigerant flow passages 5B and four return refrigerant flow passages 5D are alternately arranged in the circumferential direction.

In FIG. 4, the tip refrigerant passage region 5C at the tip of the tip side member 30 is a space communicating with the four vertical refrigerant channels 5B and the four return refrigerant channels 5D (see FIG. 5). ing.
In FIG. 4, the refrigerant supplied from the coiled tube 6 flows from the pipe 4 through the radial refrigerant flow channel 5A and the vertical refrigerant flow channel 5B to reach the tip refrigerant passage area 5C. The cold heat of the refrigerant that has reached the front end portion refrigerant passage area 5C is injected into the ground at the tip of the freezing pipe 10 through the drilling bit portion 7, and the ground is frozen. Then, it flows through the return refrigerant flow path 5D, and returns from the hollow portion of the freezing pipe 10 to the ground side via the tapered region 4T (arrow R3 in FIG. 3).

Here, the cross-sectional area of the vertical direction refrigerant flow path 5B, the tip portion refrigerant passage area 5C, and the return refrigerant flow path 5D is the cross-sectional area of the area between the inner wall of the drilling rod 10 and the coiled tube 6 (arrow The region where the refrigerant flows as indicated by R3). Therefore, the flow velocity of the refrigerant R flowing in the vertical direction refrigerant flow passage 5B, the tip portion refrigerant passage region 5C, and the return refrigerant flow passage 5D is equal to or higher than the flow velocity of the refrigerant indicated by the arrow R3.
In general, it is known that when a refrigerant flows in a flow path, turbulent flow faster in flow than laminar flow is superior in heat transferability (heat transfer coefficient). In the illustrated embodiment, as described above, the flow velocity of the refrigerant R flowing through the vertical direction refrigerant flow passage 5B, the tip portion refrigerant passage region 5C, and the return refrigerant flow passage 5D is faster than the flow velocity of the refrigerant indicated by the arrow R3. Excellent mobility.
Therefore, the ground freezing effect by the refrigerant R flowing in the vertical direction refrigerant flow path 5B, the tip portion refrigerant passage area 5C, and the return refrigerant flow path 5D is the refrigerant flowing in the area between the inner wall of the drilling rod 10 and the coiled tube 6 It is demonstrated without inferiority to the ground freezing effect by R3.

  In FIG. 4 and FIG. 5, the radial direction refrigerant flow path 5A extends in the horizontal direction, but can extend downward (obliquely extend downward) as it goes radially outward. is there. Here, it is disadvantageous that the radial direction refrigerant flow path 5A extends upward (extends obliquely upward) as going radially outward, which causes the resistance of the refrigerant R to be increased, which is a disadvantage. However, as long as the cold heat of the refrigerant R is transmitted to the front end (ground end: lower end) of the front end side member 30, the radial refrigerant flow path 5A may extend obliquely upward. .

In FIG. 4, the valve mechanism 3 is provided at a position on the ground side in the tip end side member 30 and at which the end (tip or lower end) of the pipe 4 communicates. In the state shown in FIG. 4 (during freezing), the valve body 3B is seated on the valve seat 3C due to the elastic repulsive force of the spring 3A. The elastic repulsive force of the spring 3A is weaker than the pressure of the drilling water W at the time of drilling a hole and is adjusted stronger than the supply pressure of the refrigerant R at freezing (pressure immediately above the valve body 3B at the time of refrigerant supply) It is because
Therefore, when the drilling water W is supplied at the time of drilling a hole, since the pressure of the drilling water W is stronger than the elastic repulsion of the spring 3A, the valve body 3B has the elastic repulsion of the spring 3A. The valve body 3B is not pressed downward against the valve seat 3C, and the valve mechanism 3 is open.
On the other hand, at the time of freezing, since the supply pressure of the refrigerant R (pressure immediately above the valve body 3B at the time of refrigerant supply) is weaker than the elastic repulsion of the spring 3A, the elastic repulsion of the spring 3A presses the valve 3B upward. Is seated on the valve seat 3C, and the valve mechanism 3 is closed.

As described above, the spring 3A of the valve mechanism 3 is housed in the hollow cylindrical spring housing portion 12. The spring storage portion 12 is made of a material (the material is not particularly limited) through which the refrigerant does not pass, and the refrigerant R passing through the tip refrigerant passage region 5C passes the region outside the side surface of the spring storage portion 12 It does not contact the spring 3.
At the center of the bit tip end portion 7A (see FIG. 6) of the drilling bit portion 7 disposed at the bottom portion (ground end portion) of the tip end side member 30, a jet hole 7B for drilling water is formed.
A radially inner side of the spring storage portion 12 is a spring 3A storage space.

The drill bit portion 7 is made of iron having excellent thermal conductivity, and can efficiently transmit the cold heat of the refrigerant R flowing through the tip portion refrigerant passage region 5C to the ground G.
In FIG. 6 showing the end face shape of the drilling bit portion 7, the bit tip portion 7A of the drilling bit portion 7 (the portion located at the underground tip of the drilling rod 10) is disk-shaped and the ground G side (ground On the middle surface, a plurality of (six in the embodiment) bits 7D protruding toward the ground G side are provided at equal intervals in the circumferential direction. As described above, at the center of the bit tip portion 7A of the drilling bit portion 7, the injection port 7B for spraying the drilling water W into the ground is formed.
The thickness dimension (dimension D in FIG. 4) of the bit tip portion 7A of the drilling bit portion 7 is a dimension to which the cold heat of the refrigerant is conducted and has a strength that can withstand use at the time of drilling is necessary.

In FIG. 4, the refrigerant R is supplied from the coiled tube 6 to the pipe 4 of the distal end side member 30, passes through the pipe 4, and reaches the valve mechanism 3. As described above, since the supply pressure of the refrigerant R (pressure immediately above the valve body 3B at the time of refrigerant supply) is smaller than the elastic repulsive force of the spring 3A, the valve mechanism 3 remains closed (closed). It can not pass through the valve mechanism 3.
The refrigerant R bypasses the valve mechanism 3 and the tip of the tip of the freezing pipe (the tip of the tip side member 30) via the radial direction refrigerant flow path 5A and the vertical direction refrigerant flow path 5B branched from the branch portion 4A of the pipe 4 It passes the refrigerant passage area 5C. The cold heat of the refrigerant R flowing through the front end portion refrigerant passage area 5C is introduced into the ground G via the drilling bit portion 7 and freezes the ground at the tip of the freezing pipe 10.
The refrigerant R that has passed through the refrigerant passage area 5C at the front end of the front end side member 30 returns to the tapered area 4T of the pipe 4 via the return refrigerant flow channel 5D, passes through the freezing pipe 10 and returns to the ground side ( See Figure 3).

According to the illustrated embodiment, the drilling rod can be used repeatedly, and the combination of the gauge rods can accommodate various depths. Accordingly, the cost and labor of the freezing method can be reduced. Further, it is possible to omit the on-site leak inspection because of using a rod which maintains airtightness when connected.
Then, after boring the boring hole with the drilling rod 10, when the coiled tube 6 is inserted, since the drilling rod 10 functions as the freezing tube 10, a plurality of steps of pulling out the drilling rod and inserting the freezing tube Can be omitted.

In the illustrated embodiment, since the refrigerant flow path 5 (5A to 5D) for supplying the refrigerant R is formed at the tip of the freezing pipe 10, it is possible to freeze the ground at the tip of the freezing pipe 10. That is, the refrigerant R can be supplied to the area (ground side) ahead of the valve mechanism 3 to freeze the area at the tip of the freezing pipe 10.
Thus, if the shield machine approaches the shaft and is to freeze the area between the shaft and the shield machine, in the illustrated embodiment, a portion of the wall of the shaft is drilled and frozen as in the prior art. There is no need to arrange the tube. According to the illustrated embodiment, placing the freezing tube near the shaft can freeze the area between the shield machine and the shaft.
In other words, in the illustrated embodiment, when the shield machine approaches the shaft and freezes between the shaft and the tip of the shield machine, it is necessary to drill a part of the wall of the shaft for the frozen tube construction. It will not damage the wall of the shaft.

Further, according to the illustrated embodiment, the highly airtight drilling rod 10 is reused as a freezing tube, and at the time of removing the freezing tube, connection points between rods of unit length of the drilling rod 10 ( Since the screw is pulled out to the ground side while unscrewing the portion screwed by the male screw and the female screw, the rod of unit length after the screwing is released can be reused.
And when drawing out the drilling rod 10 which has acted as a freezing pipe, it is not necessary to perform gas cutting etc. like the freezing pipe drawing operation in the prior art, and use of a firearm is unnecessary. Therefore, the safety of the freezing pipe removal work and the environmental conservation are improved.

Furthermore, according to the illustrated embodiment, since the valve mechanism 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 during boring. The operation of closing the valve during freezing operation is automatically performed by appropriately adjusting the supply pressure of the drilling water W and the refrigerant R (pressure immediately above the valve body 3B at the time of supplying the refrigerant) and the elastic coefficient of the spring. The valve opening and closing operation is unnecessary.
Further, according to the illustrated embodiment, at the time of withdrawal of the freezing tube 10, the filling material (filling material for filling the borehole) can be discharged from the tip to fill the drilling space, so freezing is performed. It is easy to fill the hole after the pipe is pulled out. In this case, as in the case of 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 formed of a coiled tube which does not need to be cut off, the refrigerant supply pipe 6 can be easily pulled to the ground side.
Then, the coolant supply piping 6 is easily pulled out to the ground side, thereby facilitating additional drilling of the borehole using the drilling rod that constitutes the outermost tube in the radial direction of the freezing tube 10 You can do it.

  It should be noted that the illustrated embodiment is merely an example, and is not a description for the purpose of limiting the technical scope of the present invention.

3 ... valve mechanism 3A ... spring 3B ... valve body 3C ... valve seat 4 ... piping 5 ... refrigerant flow path 6 ... coiled tube 10 ... freezing tube (cutting Hole rod)
30 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ··

Claims (5)

A drilling rod which is composed of a plurality of rods and jets drilling water and drills a borehole;
Having a seamless refrigerant supply pipe inserted into the drilling rod,
In the vicinity of the tip of the drilling rod, there is provided a valve mechanism that opens with pressure of drilling water but closes with supply pressure of refrigerant, branches from piping through which drilling water flows, bypasses valve mechanism and cuts away A freezing pipe characterized in that a refrigerant flow path for supplying a refrigerant to the tip of a hole rod is formed.   The valve mechanism includes a valve seat and a valve body biased in a direction to be seated on the valve seat by the elastic repulsive force of the spring. The elastic repulsive force of the spring is weaker than the pressure of the drilling water, and the refrigerant The freeze tube of claim 1, wherein the freeze tube is adjusted more strongly than the supply pressure.   The freezing pipe can make the drilling rod into a single pipe state at the time of drawing, and has a function of discharging the filling material from the tip of the drilling rod and filling back the drilling space. Or freezing tube. At the time of drilling, the borehole is drilled while injecting drilling water using a drilling rod composed of a plurality of rods,
During freezing, the drilling rod remains,
Insert a seamless coolant supply pipe into the drilling rod,
Switch the drilling water channel and the coolant channel by the valve mechanism provided near the tip of the drilling rod,
The drilling rod acts as a freezing tube after the coolant supply tube is inserted,
A freezing method characterized in that a refrigerant is supplied from a refrigerant supply pipe and the supplied refrigerant is supplied to the tip of the freezing pipe.   The freezing method according to claim 4, wherein the drilling rod can be made into a single tube state at the time of freezing tube withdrawal, and the filling material is discharged from the tip of the drilling rod to fill back the drilling space.

Images