JP7220959B2 - Ground Freezing Method, Freezing Pipe Unit - Google Patents

Description

TECHNICAL FIELD The present invention relates to a ground freezing construction method and a freezing pipe unit for freezing the surrounding ground by circulating a coolant through freezing pipes installed in the ground.

The ground freezing method of the brine circulation method freezes the ground around the frozen pipe with the cold heat of the coolant (brine) that is cooled by a refrigerator and circulates through the frozen pipe installed in the ground. be. In recent years, this ground freezing method has been used to stabilize the surrounding ground and stop water leakage when constructing underground structures with large cross-sections at great depths, as disclosed in Patent Documents 1 and 2, for example. It is adopted as a protective work to plan.

A freeze pipe unit used in a brine circulation ground freezing method includes a freeze pipe, a supply pipe, a recovery pipe, and a packer, as disclosed in FIG. 4 of Patent Document 3. In Patent Document 3, perforated steel pipes for ground improvement are connected to both ends of the frozen pipe. One side (tip side) of the cryo-tube is closed with a packing material and the other side is closed with a single packer. The packer is inserted in the perforated steel tube, not in the frozen tube. The tip of the supply tube is arranged in the vicinity of the filler in the freezing tube, and the tip of the recovery tube is arranged in the vicinity of the packer. The middle part of the supply pipe and the recovery pipe is held by a packer, and the rear end part is connected to the refrigerator. Then, the coolant cooled by the refrigerator is supplied through the supply pipe into a predetermined section in the freezing pipe, and the coolant is circulated so as to be recovered from the predetermined section to the refrigerator through the recovery pipe, Freeze the ground around a given section. Conversely, there is also a method of closing the tip side of the freezing tube with a packer (for example, Patent Document 4).

On the other hand, Patent Literature 5 discloses a ground freezing method using a carbon dioxide gas injection method in which liquefied carbon dioxide gas is injected into the ground and the surrounding ground is frozen by the heat of vaporization. A frozen pipe unit used in this ground freezing construction method includes a pipe material made up of a so-called sleeve pipe, a pumping pipe inserted into the pipe material, two inner pipes, and a packer. The pumping pipe is held by a packer. The two inner tubes are connected to the packer. The packer, pumping pipe and inner pipe are axially movable within the pipe material. After positioning the double packer in the vicinity of the injection hole provided at a predetermined position of the pipe material, compressed air is supplied from the air supply source into the double packer through one of the inner pipes to expand the double packer. , both sides of the injection hole in the pipe material in the pipe axial direction are closed with a double packer (see FIG. 4 of Patent Document 5). Alternatively, one side of the injection hole in the pipe material in the pipe axial direction is closed with a single packer (see FIG. 5). Then, liquefied carbon dioxide gas is supplied into the packer or the pipe material through the pumping pipe. Then, the liquefied carbon dioxide pushes up the rubber sleeve from the injection hole and is injected into the surrounding ground. The heat of vaporization of the injected liquefied carbon dioxide freezes the ground around the pipe material. Compressed air in the packer is exhausted through the other inner tube.

Japanese Patent Application Laid-Open No. 2019-31810 Japanese Patent No. 6257814 JP-A-2005-344460 JP 2019-183441 A Japanese Patent Application Laid-Open No. 2003-239270

In order to freeze the ground over a long section, it is necessary to install a freezing pipe over a long distance in the ground. However, if the coolant is circulated all at once in the long internal space of the freezing pipe, temperature distribution may occur and the surrounding frozen state may become uneven. There is also the problem of becoming In addition, there is a concern that the continuous circulation of the coolant in the frozen pipe for a long period of time creates an excessive amount of frozen soil in contrast to the frozen soil required for ground stabilization and water stoppage.

In addition, for example, as in Patent Document 3, depending on the geology, only a predetermined location in the ground is frozen, or depending on changes in the surrounding environment and other circumstances, the frozen location and the frozen area in the ground are changed. In such a case, it is difficult to change the frozen location or the frozen area after installing the frozen pipe in the ground.

An object of the present invention is to provide a ground freezing construction method and a freezing pipe unit that can freeze the ground evenly and efficiently and easily change the freezing point and the freezing range of the ground.

The ground freezing construction method of the present invention includes an installation step of installing a freezing pipe in the ground, inserting a supply pipe, a recovery pipe, a fluid pipe, and a plurality of packers into the freezing pipe, and inserting the packer in the axial direction of the freezing pipe. an inflating step of inflating a plurality of packers so as to block the freezing tubes by introducing fluid into the packers through the fluid tubes; and a freeze formed by the inflation of the plurality of packers. A circulation freezing step of supplying the coolant through the supply pipe to the blocked section in the pipe and recovering the coolant from the blocked section through the recovery pipe to circulate the coolant and freeze the ground around the blocked section; A shrinking step of causing the fluid in the packer to flow out through the fluid tube to shrink the plurality of packers, and a moving step of moving the supply tube, the recovery tube, the fluid tube, and the plurality of contracted packers in the tube axis direction within the freezing tube. including.

Further, the freezing pipe unit of the present invention includes a freezing pipe installed in the ground, a supply pipe for supplying coolant into the freezing pipe, a recovery pipe for collecting the coolant in the freezing pipe, and a packer closing the freezing pipe. and a fluid tube through which fluid flows into the packer. With the frozen pipe closed by a packer, the coolant is supplied into the frozen pipe through the supply pipe, and the coolant is recovered from the frozen pipe through the recovery pipe, thereby circulating the coolant and removing the ground around the frozen pipe. Freeze. In the freezing tube unit of the present invention, the packer is composed of a plurality of packers, expands to block the freezing tube when fluid flows in through the fluid tube, and contracts when fluid flows out through the fluid tube. A supply tube, a recovery tube, a fluid tube, and a plurality of packers are inserted into the freezing tube and arranged at predetermined positions in the axial direction of the freezing tube. The supply pipe communicates with the blocked section in the vicinity of one packer in the blocked section in the freezing tube blocked by a plurality of packers, and the recovery pipe communicates with the blocked section in the vicinity of the other packer in the blocked section. are in communication. With the packer contracted, the supply tube, recovery tube, fluid tube, and packer can move in the tube axis direction within the freezing tube.

According to the ground freezing construction method and frozen pipe unit of the present invention as described above, a plurality of packers are arranged in the frozen pipe at predetermined intervals in the axial direction of the pipe, fluid is caused to flow into each packer through the fluid pipe, and each packer is The expansion creates a closed section of predetermined length within the cryo-tube. By circulating the coolant through the supply pipe and the recovery pipe in this blocked section , the coolant spreads throughout the blocked section , and the ground in the predetermined section around the blocked section is reliably frozen. be able to. Further, when the freezing of the ground in the predetermined section is completed, the fluid in the packer is discharged through the fluid pipe to contract the packer. Then, the supply pipe, the recovery pipe, the fluid pipe, and the packer are moved to a predetermined position in the frozen pipe surrounded by the unfrozen ground adjacent to the frozen ground in the predetermined section, and then the expansion process and circulation described above. A freezing process, a shrinking process, and a moving process are repeated in order. As a result, even if the freezing pipe is installed over a long distance, it is possible to uniformly and efficiently freeze the ground around the freezing pipe over a wide range for each predetermined section. In addition, depending on the geology, changes in the surrounding environment, and other circumstances, the number of times the expansion process, the circulation freezing process, the shrinking process, and the moving process described above are repeated in order, or the supply pipe and recovery pipe in the freezing pipe can be set. , fluid tube, and packer can be changed, and the position at which the packer is placed can be changed. Therefore, even after the freezing pipe is installed in the ground, it is possible to freeze only a predetermined location in the ground, and it is possible to easily change the frozen location and the frozen area in the ground. becomes.

As described above, according to the ground freezing method and the freezing pipe unit of the present invention, the ground can be frozen evenly and efficiently, and the freezing point and the freezing range of the ground can be easily changed. Moreover, even when it is necessary to continue circulating the coolant in the frozen pipe for a long period of time, it is possible to restrictly cool a part of the frozen pipe in the longitudinal direction, thereby suppressing excessive frozen soil growth.

It is a figure showing an example of construction of an underground structure with a large cross section. It is a figure showing an example of construction of an underground structure with a large cross section. 1 is a facility configuration diagram of a ground freezing construction method of a brine circulation system; FIG. 1 shows a cryo-tube unit according to a first embodiment of the present invention; FIG. Figure 5 is a transverse cross-sectional view of the freeze tube unit of Figure 4; 6 is an enlarged view of the vicinity of the packer of FIG. 5; FIG. Figure 6 is a cross-sectional view of the tip of the freeze tube of Figure 5; FIG. 6 is a cross-sectional view near the holding carriage in FIG. 5 ; FIG. 4 shows a cryo-tube unit according to a second embodiment of the present invention; FIG. 10 is a cross-sectional view of the freeze tube unit of FIG. 9; FIG. 11 shows a cryo-tube unit according to a third embodiment of the present invention; FIG. 11 shows a cryo-tube unit according to a fourth embodiment of the present invention; Figure 13 is a cross-sectional view of the freeze tube unit of Figure 12; FIG. 10 is a diagram showing another construction example of an underground structure; FIG. 10 is a diagram showing another construction example of an underground structure; FIG. 11 shows a cryo-tube unit according to a fifth embodiment of the present invention; It is the figure which showed 1 process of the freezing construction method using the freezing pipe unit of FIG. FIG. 11 shows a cryo-tube unit according to a sixth embodiment of the present invention; FIG. 19 is a view showing one step of a freezing construction method using the freezing tube unit of FIG. 18;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each figure, the same reference numerals are given to the same or corresponding parts.

First, application examples of the ground freezing construction method and the frozen pipe unit of the embodiment will be described.

1 and 2 are diagrams showing construction examples of an underground structure 1 with a large cross section. 1 shows a horizontal section of the underground structure 1, and FIG. 2 shows a vertical section of the underground structure 1. As shown in FIG. In this example, the underground structure 1 is a tunnel with a large cross-section that is constructed in the deep ground G before carrying out construction work to connect the ramp tunnel 3 to the main tunnel 2 in which the vehicle travels.

First, as shown in FIG. 1( a ), a starting base 4 is constructed around a predetermined location of the main tunnel 2 . Also, an arrival station 5 is constructed around another predetermined location of the main line tunnel 2, and a ramp tunnel 3 is connected to the arrival station 5. - 特許庁The distance from the departure base 4 to the arrival base 5 is, for example, several hundred meters or more.

Then, a plurality of shield tubes 7 and 8 are annularly installed from the departure base 4 toward the arrival base 5 by a known shield construction method (see FIG. 2). At this time, after a plurality of leading shield tubes 7 are installed, the trailing shield tubes 8 are excavated while scraping the wall of a part of the leading shield tubes 7, and the trailing shield tubes 7 are formed between the leading shield tubes 7. 8 is installed. As a result, as shown in FIG. 2(a), the leading shield pipe 7 and the trailing shield pipe 8 are alternately buried in the ground G around the tunnels 2 and 3, forming a tunnel-shaped outer shell shield 1. ' is formed. Also, a portion of the trailing shield tube 8 is bitten into the leading shield tube 7 .

Next, a freezing method of freezing the ground G around the shield tubes 7 and 8 is performed. The details of this freezing method will be described later. By performing the freezing method, as shown in FIGS. 1(b) and 2(b), a frozen soil wall 6 having high strength and water stopping performance is formed around the outer shell shield 1'.

Next, after excavating the inside of the shield tubes 7 and 8 to connect the adjacent shield tubes 7 and 8, the shield tubes 7 and 8 are crossed as shown in FIGS. A cylindrical lining body 9 is constructed as follows. This completes the construction of the underground structure 1 . After that, predetermined construction work is carried out in the underground structure 1, and a ramp tunnel 3 is connected to the main tunnel 2 as shown in FIG. 1(c).

Next, the equipment configuration for executing the ground freezing method of the embodiment will be described.

FIG. 3 is a facility configuration diagram of the ground freezing method of the brine circulation system. An appropriate number of cryo-tube units 10 are provided and installed in the shield tubes 7 and 8 as shown in FIG. Details of the structure and function of the cryo-tube unit 10 will be described later. The refrigerator 40 and the machine room are provided, for example, at the departure base 4 or the arrival base 5 described above. The refrigerator 40 has a condenser 41 , a cooler 42 and a compressor 43 .

Cooling water is circulated between the cooling tower 44 and the condenser 41 through the pipes 51 to 53 by the pumping force of the circulation pump 45 provided in the machine room. Refrigerant is circulated between the condenser 41 and the cooler 42 through the pipes 54 to 56 by the pumping force of the compressor 43 of the refrigerator 40 . Due to the pumping force of the circulation pump 46, the coolant ( brine) is circulated. As the coolant, for example, an aqueous solution of calcium chloride is used.

The condenser 41 cools the coolant with cooling water cooled by the cooling tower 44 . The cooler 42 cools the coolant with the refrigerant cooled by the condenser 41 . The freezing tube unit 10 freezes the ground G around the shield tubes 7 and 8 with the coolant cooled by the cooler 42 .

A fluid pipe 14b provided in the cryo-tube unit 10 is connected to a fluid supply source 47 such as a compressor. The wire rods 16a and 16b provided in the freezing tube unit 10 are made of wires or the like and connected to a pulling machine 48 such as a winch.

Next, the structure of the freezing tube unit 10 of the first embodiment will be described with reference to FIGS. 4 to 8. FIG.

FIG. 4 is a diagram showing an installed state of the freezing tube unit 10 of the first embodiment. 4(a) is a cross-sectional view perpendicular to the axial direction of the shield tubes 7 and 8, FIG. 4(b) is a perspective cross-sectional view of the tip side of the shield tubes 7 and 8, and FIG. , a perspective sectional view of the rear end side of the shield tubes 7, 8. FIG. A plurality of freezing tubes 11 provided in the freezing tube unit 10 are installed on the inner peripheral surfaces of the shield tubes 7 and 8 buried in the ground G as described above. The diameter of each shield tube 7, 8 is, for example, approximately 4 meters. The diameter of freezing tube 11 is, for example, about 160 mm. The shield tubes 7 and 8 are examples of "large-diameter tubes" of the present invention.

FIG. 5 is a cross-sectional view of the freezing tube unit 10. As shown in FIG. 5(a) and 5(b) have cross sections that are different from each other by 90 degrees around the tube axis of the freezing tube 11. FIG. Supply pipes 12a and 12b, recovery pipe 13, fluid pipes 14a and 14b, packers 15a and 15b, wires 16a and 16b, and holding truck 17 are inserted into freezing pipe 11. FIG. The packers 15a and 15b are arranged in the freezing tube 11 at predetermined intervals in the tube axial direction.

FIG. 6 is an enlarged view of the vicinity of the packer 15a in FIG. 5(b). FIG. 7 is a cross-sectional view of the tip of the freezing tube 11 and the vicinity of the packers 15a and 15b. As shown in FIGS. 5 to 7, packers 15a and 15b have cylindrical frames 18a and 18b, respectively.

The tip of the frame 18a of the packer 15a arranged on the tip side of the freezing tube 11 (left side in FIGS. 5 to 7) is closed. The frame 18a is formed with a supply channel 18i (FIG. 5(a)), a fluid channel 18k (FIGS. 5(b) and 6), and insertion holes 18g and 18h (FIG. 7).

The front end of the supply pipe 12a is connected to the rear end of the frame 18a (right end in FIGS. 5 to 7) so as to communicate with the supply path 18i (FIG. 5(a)). One end of the supply path 18i of the frame 18a is open, and the supply pipe 12a communicates with the space (closed section X described later) between the packers 15a and 15b in the freezing tube 11 via this supply path 18i. ing. A gap between the supply path 18i and the supply pipe 12a is airtightly sealed by a sealing member (not shown).

Further, the front end of the fluid tube 14a is connected to the rear end of the frame 18a so as to communicate with the fluid passage 18k (FIG. 5(b)). A gap between the fluid path 18k of the frame 18a and the fluid pipe 14a is hermetically sealed by a sealing member (not shown).

As shown in FIGS. 5 and 7, a frame 18b of the packer 15b arranged on the rear end side of the freezing tube 11 is formed with a supply channel 18i, a recovery channel 18j, a fluid channel 18k, and insertion holes 18g and 18h. ing. The rear end of the supply pipe 12a is connected to the front end of the frame 18b so as to communicate with the supply path 18i (FIG. 5(a)). The front end of the supply pipe 12b is connected to the rear end of the frame 18b so as to communicate with the supply path 18i. The supply pipe 12b and the supply pipe 12a communicate with each other through the supply path 18i of the packer 15b. The gaps between the supply path 18i of the frame 18b and the supply pipes 12a and 12b are hermetically sealed by sealing members (not shown).

A front end portion of the recovery pipe 13 is connected to the rear end portion of the frame 18b so as to communicate with the recovery path 18j. One end of the recovery path 18j of the frame 18b is open, and the recovery tube 13 communicates with the space (closed section X) between the packers 15a and 15b in the freezing tube 11 via this recovery path 18j. . A gap between the recovery path 18j and the recovery pipe 13 is airtightly sealed by a sealing member (not shown).

A rear end portion of the fluid tube 14a is connected to the front end portion of the frame 18b so as to communicate with the fluid passage 18k (FIG. 5(b)). A distal end portion of the fluid pipe 14b is connected to the rear end portion of the frame 18b so as to communicate with the fluid passage 18k. The gaps between the fluid passage 18k of the frame 18b and the fluid pipes 14a and 14b are hermetically sealed by sealing members (not shown).

As shown in FIG. 3, the other end of the supply tube 12b, the other end of the recovery tube 13, and the other end of the fluid tube 14b are pulled out from the rear end of the freezing tube 11, respectively. The supply pipe 12 b is connected to the relay branch pipe 60 , the recovery pipe 13 is connected to the relay branch pipe 61 , and the fluid pipe 14 b is connected to the fluid supply source 47 .

As shown in FIG. 7, insertion holes 18g and 18h are formed in parallel with the tube axis direction of the freezing tube 11 in the frames 18a and 18b of the respective packers 15a and 15b. Wire rods 16a and 16b are inserted through the insertion holes 18g and 18h, respectively. As a result, the wires 16a and 16b pass through the packers 15a and 15b in the tube axis direction of the freezing tube 11 .

The wire 16b is connected (fixed) to the frames 18a and 18b. The wire rod 16a is movable in the axial direction of the freezing tube 11 within the insertion holes 18g of the frames 18a and 18b. The gaps between the insertion holes 18g and 18h and the wire rods 16a and 16b are substantially airtightly sealed by sealing members (not shown). The rear ends of the wires 16a and 16b are led out from the rear end side of the freezing tube 11 and connected to the traction machine 48, as shown in FIG.

As shown in FIGS. 5 to 7, a tubular rubber 19 is provided on the peripheral surface of each frame 18a, 18b. A rubber 19 covers the peripheral surface of each frame 18a, 18b. Both ends of each rubber 19 are held by holding members 20a, 20b, 21a and 21b.

Specifically, as shown in FIG. 6, one end (right side) of the rubber 19 of the packer 15a is held between a sleeve 20a attached to the peripheral surface of the frame 18a and a retaining ring 21a attached to the sleeve 20a. ing. The sleeve 20a is secured to the frame 18a with screws 22. As shown in FIG. The other end (left side) of the rubber 19 is sandwiched between a cylindrical slider 20b attached to the peripheral surface of the frame 18a and a retaining ring 21b attached to the slider 20b. The slider 20b is not fixed to the frame 18a and is slidable along the frame 18a in the direction of the tube axis for a predetermined length. A flange portion 18y is formed at the tip of the frame 18a to prevent the slider 20a from falling off. That is, one end of the rubber 19 is a fixed end and the other end is a free end. Each end of the rubber 19 of the packer 15b is similarly held by holding members 20a, 20b, 21a, 21b and the peripheral surface of the frame 18b.

Inflow/outflow holes 18p communicating with the fluid passage 18k are formed in the peripheral surfaces of the frames 18a and 18b (FIGS. 5B and 6). The inflow/outflow hole 18p is covered with a rubber 19. As shown in FIG. An elastic member 23 is provided between the rubber 19 and the frames 18a and 18b. The elastic member 23 consists of a coil spring, and pulls the other end (the left end in FIG. 6) of the rubber 19 in the axial direction of the freezing tube 11 by urging the slider 20b toward the flange portion 18y. to pull the central portion of the rubber 19 toward the peripheral surfaces of the frames 18a and 18b.

As shown in FIG. 7, the tip of the freezing tube 11 is closed with a cover 24 . A turn box 25 is attached to the cover 24 . A reel group 26 and a pulley 27 are provided in the turn box 25 . The wire rod 16a protruding to the tip side of the frame 18a through the insertion hole 18g of the frame 18a of the packer 15a passes through the through hole 24a of the cover 24, passes through the reel group 26 in the turn box 25, and moves to the pulley 27. is hung on After the wire rod 16a is turned by the pulley 27, it passes through the through hole 24b of the cover 24 via the reel group 26 and is connected to the tip of the frame 18a. The gaps between the through holes 24a and 24b and the wire rod 16a are hermetically sealed by a sealing member (not shown).

As shown in FIG. 5, a holding carriage 17 is inserted in the freezing tube 11 on the rear end side of the packer 15b. FIG. 8 is a cross-sectional view of the vicinity of the holding carriage 17. As shown in FIG.

The holding carriage 17 has a plurality of holding portions 17a, 17b, 17c, 17d, and 17e and a plurality of wheels 17t. Holding portions 17a, 17b, 17c, 17d, and 17e individually hold supply pipe 12b, recovery pipe 13, fluid pipe 14b, wire 16a, and wire 16b, respectively. At least one of the supply pipe 12b, the recovery pipe 13, the fluid pipe 14b, and the wires 16a, 16b is fixed to the corresponding holding portion 17a-17e. Each wheel 17t rolls on the inner peripheral surface of the freezing tube 11 in the tube axial direction. A suitable number of holding carts 17 are arranged in the freezing tube 11 .

Next, a ground freezing method using the frozen pipe unit 10 of the first embodiment will be described.

First, as described above, before or after burying the shield tubes 7 and 8 in the ground G, a plurality of freezing tubes 11 are installed in each of the shield tubes 7 and 8 as shown in FIG. . More specifically, in this installation process, the freezing point is placed at the positions of the inner peripheral surfaces of the shield tubes 7 and 8 corresponding to the outer peripheral side and the inner peripheral side of the outer shell shield 1' (FIG. 2) of the underground structure 1 described above. The pipes 11 are arranged parallel to the axial direction of the shield pipes 7 and 8 and at predetermined intervals in the circumferential direction of the pipes. As a result, the frozen pipe 11 is installed in the ground G through the shield pipes 7 and 8 .

Next, as shown in FIGS. 5 to 8, packers 15a and 15b, wire rods 16a and 16b, supply pipes 12a and 12b, recovery pipe 13, fluid pipes 14a and 14b, and holding carriage 17 are provided in freezing pipe 11. (interpolation step).

Specifically, in the insertion step, first, packers 15a and 15b, wire rod 16b, supply pipes 12a and 12b, recovery pipe 13, and fluid pipes 14a and 14b are connected outside freezing pipe 11 . Also, one end of the wire rod 16a is connected to the frame 18a of the packer 15a. Next, the end of the wire rod 16a not connected to the packer 15a is inserted into the tube from the rear end of the freezing tube 11 (right side in FIG. 7), and the tip of the freezing tube 11 (left side in FIG. 7) is inserted into the tube. ). Then, the drawn wire 16a is passed through the insertion holes 24a and 24b of the cover 24 and the reels 26 and the pulley 27 of the turn box 25 shown in FIG. Next, the end of the wire rod 16 a is inserted into the freezing tube 11 from the front end and pulled out from the rear end of the freezing tube 11 . Then, the drawn wire 16a is inserted through the insertion holes 18g of the packers 15a and 15b. Also, a cover 24 and a turn box 25 are attached to the tip of the freezing tube 11 .

After the rear end of the wire rod 16a passed through the packers 15a and 15b is connected to the traction machine 48 (FIG. 3), the wire rod 16a is pulled by the traction machine 48, thereby pulling the wire rod 16a as shown in FIGS. , the packers 15a and 15b, wire rods 16a and 16b, supply pipes 12a and 12b, recovery pipe 13, and fluid pipes 14a and 14b are drawn into the freezing pipe 11, and the packers 15a and 15b are arranged at predetermined positions at predetermined intervals. do.

At the time of drawing, the supply pipe 12b, the recovery pipe 13, the fluid pipe 14b, and the wires 16a and 16b on the rear side of the packer 15b are held by an appropriate number of holding trucks 17, and the holding trucks 17 also hold the freezing pipes 11. insert inside.

As another example, an appropriate number of holding carriages 17 may be inserted between the packers 15a and 15b, and the holding carriages 17 may hold the supply pipe 12a, the fluid pipe 14a, and the wires 16a and 16b. good.

Next, the shield tubes 7 and 8 are filled with a filler (filling step). The filling material used in this filling step consists of, for example, mortar earth.

Next, the freezing tube 11 is filled with an antifreeze material (filling step). The antifreeze used in this filling process consists, for example, of the same aqueous calcium chloride solution as the coolant (brine).

Next, the fluid supplied from the fluid supply source 47 is caused to flow into the respective packers 15a and 15b through the fluid pipes 14a and 14b, and the packers 15a and 15b as shown in FIGS. 5(a) and 6(b). is expanded (expansion step). Specifically, in this expansion step, a fluid such as an antifreeze liquid or compressed air is caused to flow from the fluid supply source 47 into the fluid pipe 14b. Then, as indicated by arrows in FIG. 5(b), the fluid flows from the fluid tube 14b through the fluid passage 18k of the packer 15b and the inflow/outflow hole 18p, and the rubber 19 covering the peripheral surface of the frame 18b and the peripheral surface of the frame 18b. flows between Also, this fluid flows from the fluid passage 18k of the frame 18b through the fluid pipe 14a, the fluid passage 18k and the inlet/outlet hole 18p of the packer 15a, and flows between the peripheral surface of the frame 18a and the rubber 19 covering the peripheral surface. It flows in between (FIG. 6(a)).

The fluid inflates the rubbers 19 of the packers 15a and 15b away from the peripheral surfaces of the frames 18a and 18b and presses them against the inner peripheral surface of the freezing tube 11, thereby expanding the packers 15a and 15b and freezing them. The tube 11 is closed (FIGS. 5(a) and 6(b)).

When the rubber 19 of each packer 15a, 15b is pushed toward the inner peripheral surface of the freezing tube 11 by the fluid as described above, one end of the rubber 19 held by the sleeve 20a and the retaining ring 21a of each packer 15a, 15b is Since it is a fixed end, it does not move. On the other hand, since the other end of the rubber 19 sandwiched between the slider 20b and the retaining ring 21b is a free end, it moves in the axial direction of the freezing tube 11 together with the slider 20b (see FIG. 6(b)).

As a result of the expansion process described above, a blocked section X blocked by the packers 15a and 15b is formed in the freezing tube 11, as shown in FIG. 5(a). The supply pipes 12a, 12b communicate with the closed section X in the vicinity of the packer 15a. The recovery pipe 13 communicates with the closed section X in the vicinity of the packer 15b.

Next, the coolant cooled by the cooler 42 (FIG. 3) of the refrigerator 40 is supplied from the supply pipe 12b to the closed section X in the freezing pipe 11 through the supply pipe 12a. Then, the coolant in the blocked section X is circulated so as to be recovered to the cooler 42 through the recovery pipe 13, and the ground G around the blocked section X of the freezing pipe 11 is frozen (circulation freezing process).

Specifically, in the circulation freezing process, first, the on-off valve 62 shown in FIG. Through the valve 62, it is supplied to the supply pipe 12b. Then, the coolant passes through the supply pipe 12b, the supply channel 18i of the packer 15b, the supply pipe 12a, and the supply channel 18i of the packer 15a, as indicated by arrows in FIG. Interval X is supplied. Then, the cold heat of the coolant in the closed section X passes through the freezing tube 11 and the shield tubes 7 and 8 in which the freezing tube 11 is installed, and the filling material in the sealing tubes 7 and 8 and the closed section X is transmitted to the surrounding ground, cooling the filler and ground.

The coolant deprived of cold heat in the closed section X passes through the recovery path 18j of the packer 15b and the recovery pipe 13 as indicated by the arrow in FIG. It is collected in the cooler 42 through the relay branch pipe 61 and the pipes 58 and 59 and the like. After being cooled by the cooler 42 , the collected coolant is again supplied to the closed section X in the freezing pipe 11 , where it is deprived of cold heat and then recovered to the cooler 42 . By continuing the circulation of the coolant between the cooler 42 and the blocked section X in the freezing pipe 11 for a predetermined period of time in this way, the filling material and the ground around the blocked section X are frozen.

After freezing the ground around the closed section X, the circulation of the coolant is stopped, the fluid in the packers 15a and 15b is discharged through the fluid pipes 14a and 14b, and the packers 15a and 15b are contracted ( shrinkage process). More specifically, in this shrinking process, the fluid between the peripheral surfaces of the frames 18a and 18b of the packers 15a and 15b and the rubber 19 is forced through the inflow and outflow holes 18p of the frames 18a and 18b, the fluid passages 18k and the fluid pipes 14a and 14b. , is collected in the fluid supply source 47, and exhausted to the outside (see the arrow in FIG. 6(c)). As a result, the rubbers 19 of the packers 15a and 15b are separated from the inner peripheral surface of the freezing tube 11, and the elastic force of the elastic member 23 causes the slider 20b to slide toward the flange portion 18y. The packers 15a and 15b are contracted by being pulled toward the peripheral surfaces of 18a and 18b.

Even when the rubbers 19 of the packers 15a, 15b are drawn toward the peripheral surfaces of the frames 18a, 18b as described above, one end of the rubbers 19 of the packers 15a, 15b is fixed and does not move. On the other hand, since the other end of the rubber 19 is a free end, it moves in the axial direction of the freezing tube 11 (see FIG. 6(c)). By contracting the packers 15a and 15b as described above, the blocked state inside the freezing tube 11 is released.

Next, the wire rod 16b is pulled by the traction machine 48 (FIG. 3), and the supply pipes 12a, 12b, the recovery pipe 13, the fluid pipes 14a, 14b, and the packers 15a, 15b are pulled in the freezing pipe 11 in the pipe axial direction. Move a distance (moving step). Specifically, in this moving step, the supply pipes 12a and 12b, the recovery pipe 13, the fluid pipes 14a and 14b, and the packers 15a and 15b are moved to the freezing pipe by a distance equivalent to the length of the blocked section X in the freezing pipe 11 described above. 11 to the rear end side (rightward in FIG. 5). As a result, the packer 15a at the position shown in FIG. 5, for example, moves almost to the position of the packer 15b shown in the same figure. As a result, the supply pipes 12a and 12b, the recovery pipe 13, the fluid pipes 14a and 14b, and the packers 15a and 15b after the movement are surrounded by the unfrozen ground adjacent to the frozen ground. In this state, the unfrozen ground is frozen by executing the expansion step and the circulation freezing step. When the freezing is completed, the shrinking process and the moving process are executed to further move the packers 15a, 15b, etc. to the rear end side of the freezing tube 11 again to freeze the next unfrozen ground.

Likewise, by repeatedly executing the expansion process, the circulation freezing process, the shrinking process, and the moving process described above in order, the ground G surrounding the freezing pipe 11 installed over a long distance is While the packers 15a, 15b, etc. are sequentially moved, each predetermined section is frozen.

The above processing is performed for each freezing tube 11 installed in each shield tube 7, 8, and as shown in FIGS. Freeze G. As a result, a frozen earth wall 6 having a predetermined strength and water stopping performance is formed around the outer shell shield 1 ′ of the underground structure 1 .

According to the above-described first embodiment, a plurality of packers 15a and 15b are arranged in the freezing tube 11 at predetermined intervals in the axial direction of the tube, and the respective packers 15a and 15b are inflated, so that the predetermined A closed section X having a length is formed. The coolant is circulated through the supply pipes 12 a and 12 b and the recovery pipe 13 to the closed section X and the cooler 42 of the refrigerator 40 . Therefore, the coolant can be spread all over the blocked section X, and the ground in the predetermined section around the blocked section X can be reliably frozen.

Further, when the freezing of the ground in the predetermined section is completed, the fluid in the packers 15a and 15b is discharged through the fluid pipes 14a and 14b to contract the packers 15a and 15b. Then, the supply pipes 12a, 12b, the recovery pipe 13, the fluid pipes 14a, 14b, and the packers 15a, 15b are moved in the pipe axial direction within the frozen pipe 11, and the unfrozen ground adjacent to the ground of the frozen predetermined section is It is arranged at a predetermined position inside the freezing pipe 11 surrounded by the ground. Then, the expansion process, the circulation freezing process, the shrinking process, and the moving process described above are repeated in order. As a result, even if the freezing pipe 11 is installed over a long distance, it is possible to uniformly and efficiently freeze the ground around the freezing pipe 11 in a wide range for each predetermined section.

Further, a plurality of freezing tubes 11 are installed in a plurality of shield tubes 7 and 8 buried in the ground, and after filling each shield tube 7 and 8 with a filler, each freezing tube 11 is subjected to the above-described The expanded step, the circulating freezing step, the shrinking step, and the moving step are repeated in order. As a result, the cold heat of the coolant circulated in the blocked section X in each freezing pipe 11 is transferred to the ground around the shielding pipes 7 and 8 via the freezing pipe 11, the shield pipes 7 and 8, or the filling material. It is possible to freeze the ground evenly and efficiently in each predetermined section.

Furthermore, for each of the plurality of shield pipes 7 and 8, freezing of the surrounding ground, excavation of the inside, and construction of the lining 9 can be performed in parallel for each predetermined section. , the construction period required for construction of the underground structure 1 can be shortened.

Further, in the above-described first embodiment, the wire 16a is inserted into the freezing tube 11, and after the wire 16a is hooked on the pulley 27 in the turn box 25 attached to the tip of the freezing tube 11 to change the direction, The wire rod 16 a is led out from the rear end of the freezing tube 11 . One end of the wire rod 16a is connected to the packer 15a, and the packers 15a and 15b are connected to each other by the pipes 12a and 14a and the wire rod 16b. Then, by pulling the other end of the wire rod 16a led out from the freezing tube 11 by the traction machine 48, the supply tubes 12a and 12b, the recovery tube 13, the fluid tubes 14a and 14b, and the packers 15a and 15b are placed in the freezing tube 11. It can be easily and reliably inserted to any position. In addition, during this insertion, the stress and stress applied to the supply pipes 12a, 12b, the recovery pipe 13, the fluid pipes 14a, 14b, and the connecting portions between these pipes and the packers 15a, 15b are reduced. Damage to the connecting portion can be prevented.

Further, in the first embodiment described above, the wire rod 16b is inserted into the freezing tube 11 while being connected to the packers 15a and 15b, and one end of the wire rod 16b is led out from the rear end of the freezing tube 11. One end of the wire rod 16b is pulled by the pulling machine 48 to move the supply pipes 12a and 12b, the recovery pipe 13, the fluid pipes 14a and 14b, and the packers 15a and 15b inside the freezing pipe 11 to the rear end of the freezing pipe 11. It can be easily and reliably moved to the side. Also, during this movement, the stress and stress applied to the supply pipes 12a and 12b, the recovery pipe 13, the fluid pipes 14a and 14b, and the connecting portions between these pipes and the packers 15a and 15b can be reduced. Damage to pipes and joints can be prevented. Furthermore, by adjusting the drawing length of the wire rods 16a and 16b from the freezing tube 11, the supply tubes 12a and 12b, the recovery tube 13, the fluid tubes 14a and 14b, and the packers 15a and 15b can be arbitrarily moved inside the freezing tube 11. Can be easily placed in position.

Further, in the above-described first embodiment, the freezing tube 11 is filled with the antifreeze material before the expansion process of the packers 15a and 15b. Therefore, during circulation of the coolant, it is possible to prevent formation of aqueous foreign substances such as frost columns and ice on the surfaces of the supply pipes 12a and 12b, the recovery pipe 13, the fluid pipes 14a and 14b, or the packers 15a and 15b. can be done. In addition, when the packers 15a and 15b contract, the coolant leaks from the closed section X, preventing condensation from occurring on the inner peripheral surface of the freezing tube 11, and further suppressing the formation of aqueous foreign matter in the freezing tube 11. can be prevented. Since the movement of the supply pipes 12a and 12b, the recovery pipe 13, the fluid pipes 14a and 14b, or the packers 15a and 15b in the freezing pipe 11 is no longer hindered by the aqueous foreign matter, these are reliably moved to predetermined positions. be able to.

Further, in the above-described first embodiment, the holding carriage 17 that rolls on the inner peripheral surface of the freezing tube 11 in the tube axial direction while individually holding the supply tube 12b, the recovery tube 13, and the fluid tube 14b is It is inserted into the freezing tube 11 (Fig. 8). Therefore, when the supply pipes 12a, 12b, the recovery pipe 13, the fluid pipes 14a, 14b, and the packers 15a, 15b are inserted into or moved into the freezing pipe 11, these pipes 12a, 12b, 13, 14a, 14b are twisted or twisted. By preventing slack, each tube and packers 15a and 15b can be moved smoothly in the tube axial direction.

Further, in the above-described first embodiment, the packers 15a and 15b are provided with the elastic members 23, and the elastic members 23 bias the rubbers 19 of the packers 15a and 15b in the contraction direction. Therefore, when the fluid in the packers 15a, 15b is allowed to flow out through the fluid pipes 14a, 14b, the contraction of the packers 15a, 15b is facilitated by the elastic member 23, so that the packers 15a, 15b can be rapidly and reliably contracted. can be done. Therefore, when the supply pipes 12a and 12b, the recovery pipe 13, the fluid pipes 14a and 14b, and the packers 15a and 15b move thereafter, the smooth movement of the packers 15a and 15b is prevented from being hindered within the freezing pipe 11. can do.

In the above-described first embodiment, one end of the rubber 19 of the packers 15a and 15b that expands and contracts is a fixed end fixed to the frames 18a and 18b, and the other end extends in the tube axial direction. It has a movable free end. Therefore, when the fluid is caused to flow into the inside of the rubber 19 of the packers 15a and 15b through the fluid pipes 14a and 14b, the rubber 19 is expanded in the pipe radial direction of the freezing pipe 11 without difficulty, and the inside of the freezing pipe 11 is ensured. can be occluded. Further, when the fluid inside the rubber 19 is caused to flow out through the fluid pipes 14 a and 14 b, the rubber 19 can be naturally contracted and separated from the freezing pipe 11 .

Furthermore, in the freezing tube unit 10 of the first embodiment described above, the number of times the expansion process, the circulation freezing process, the contraction process, and the movement process described above are repeated in order, for example, according to changes in the geological features, the surrounding environment, and other circumstances. , change the length of movement of the supply pipes 12a and 12b, the recovery pipe 13, the fluid pipes 14a and 14b, and the packers 15a and 15b within the freezing pipe 11, and change the positions of the packers 15a and 15b. can be Therefore, even after the freezing pipe 11 is installed in the ground G, it is possible to freeze only a predetermined location in the ground G, and it is possible to easily change the frozen location and the frozen range in the ground G. It becomes possible to In addition, even when it is necessary to continue circulating the coolant in the freezing pipe 11 for a long period of time, it is possible to limitly cool a part of the freezing pipe 11 in the longitudinal direction, thereby suppressing excessive frozen soil growth. can be done.

In the first embodiment described above, only the straight freezing tubes 11 are installed inside the shield tubes 7 and 8, but as in the following second to fourth embodiments, bent branch freezing tubes are installed inside the shield tubes 7 and 8. It can be placed inside.

FIG. 9 is a diagram showing an installation state of the freezing tube unit 10a of the second embodiment. 9(a) shows the front end sides of the shield tubes 7 and 8, and FIG. 9(b) shows the rear end sides of the shield tubes 7 and 8. As shown in FIG. In the second embodiment, one freezing tube 11 is placed on each of the inner peripheral surfaces of the shield tubes 7 and 8 corresponding to the outer peripheral side and the inner peripheral side of the outer shell shield 1' (FIG. 2) of the underground structure 1. Placed one by one. A plurality of branch freezing tubes 31 are connected to each freezing tube 11 at predetermined intervals in the axial direction of the shield tubes 7 and 8 . In FIG. 9, some branch freezing tubes 31 are illustrated.

The branch freezing tube 31 branches from a predetermined position of the freezing tube 11 and extends along the inner peripheral surfaces of the shield tubes 7 and 8 in a direction perpendicular to the axial direction of the shield tubes 7 and 8; It extends in a direction parallel to the tube axis direction. Moreover, the branch freezing pipes 31 extend to both sides of the freezing pipe 11 in the pipe radial direction. The branch freezing pipe 31 is connected to the freezing pipe 11 at a position different from the branch position so as to merge with the freezing pipe 11 . The freezing tube 11 and branch freezing tube 31 are fixed to the inner peripheral surfaces of the shield tubes 7 and 8 .

FIG. 10 is a cross-sectional view of a freezing tube unit 10a of the second embodiment. 10(a) and 10(b) have cross sections that differ by 90° around the tube axis of the freezing tube 11. FIG. Into the freezing tube 11 are inserted supply tubes 12a, 12b, 12c, recovery tube 13, fluid tubes 14a, 14b, 14c, packers 15a, 15b, 15c, and wires 16a, 16b. Also, although not shown in FIG. 10, the aforementioned holding carriage 17 (FIG. 8) is also inserted.

As shown in FIGS. 10 and 9 , a packer 15a is arranged on the front side of one section Xa in the freezing tube 11 including the branching point between the freezing tube 11 and the branch freezing tube 31 . In addition, a packer 15 c is arranged on the rear side of one section Xa and on the front side of another section Xb in the freezing tube 11 including the connection point between the freezing tube 11 and the branch freezing tube 31 . Furthermore, a packer 15b is arranged on the rear side of the other section Xb.

The structure of the packer 15a and the connection structure of the supply pipe 12a, the fluid pipe 14a, and the wires 16a and 16b for the packer 15a are the same as those of the first embodiment shown in FIGS. The structure of the packer 15b and the connection structure of the supply pipe 12b, the recovery pipe 13, the fluid pipe 14b, and the wires 16a and 16b with respect to the packer 15b are also the same as in the first embodiment.

As shown in FIG. 10, a cylindrical frame 18c provided in the packer 15c is formed with a supply channel 18i, a fluid channel 18k and an insertion hole 18h. The rear end of the supply pipe 12a is connected to the front end of the frame 18c so as to communicate with the supply path 18i. A rear end portion of the fluid pipe 14a is connected to the front end portion of the frame 18c so as to communicate with the fluid passage 18k. The front end of the supply pipe 12c is connected to the rear end of the frame 18c so as to communicate with the supply path 18i. A front end portion of the fluid pipe 14c is connected to the rear end portion of the frame 18c so as to communicate with the fluid passage 18k. A gap between the supply channel 18i of the frame 18c and the supply pipes 12a and 12c and a gap between the fluid channel 18k and the fluid pipes 14a and 14c are hermetically sealed by sealing members (not shown).

The rear end of the supply pipe 12c is connected to the front end of the frame 18b of the packer 15b so as to communicate with the supply path 18i of the frame 18b. A rear end portion of a fluid pipe 14c is connected to the front end portion of the frame 18b so as to communicate with the fluid passage 18k of the frame 18b. A gap between the supply path 18i of the frame 18b and the supply pipe 12c and a gap between the fluid path 18k and the fluid pipe 14c are hermetically sealed by sealing members (not shown).

A frame 18c of the packer 15c is formed with an insertion hole 18h through which the wire rod 16b is inserted. Further, although not shown, the frame 18c is formed with an insertion hole through which the wire rod 16a is inserted, similar to the insertion holes 18g (FIG. 7) of the frames 18a and 18b. The gaps between the insertion holes of the frame 18c and the wires 16a and 16b are airtightly sealed by sealing members (not shown).

A peripheral surface of the frame 18 c is covered with a rubber 19 . The holding structure of this rubber 19 is similar to the frames 18a, 18b of the packers 15a, 15b. Inflow/outflow holes 18p are formed in the peripheral surfaces of the frames 18a, 18b, and 18c. An elastic member 23 is provided between the rubber 19 and the frames 18a and 18b.

In the same procedure as in the above-described first embodiment (see FIG. 7), by pulling the lead-out portion of the wire rod 16a from the freezing tube 11 with the traction machine 48, the supply tubes 12a, 12b, 12c and the recovery pipes 12a, 12b, 12c are inserted into the freezing tube 11. Tube 13, fluid tubes 14a, 14b, 14c, packers 15a, 15b, 15c and wires 16a, 16b are inserted and positioned within the tube as shown in FIGS. Then, after performing a filling step of filling the filling material into the shield tubes 7 and 8 and a filling step of filling the freezing tube 11 with the antifreeze material, the packers are expanded in order of the packers 15b→15c→15a. perform an expansion step that allows

Specifically, in the expansion step, fluid is caused to flow from the fluid supply source 47 into the fluid tube 14b. Then, as indicated by arrows in FIG. 10(b), the fluid flows from the fluid tube 14b through the fluid passage 18k of the packer 15b and the inflow/outflow hole 18p, and then onto the peripheral surface of the frame 18b and the rubber covering the peripheral surface. It flows between 19 and Also, the fluid flows from the fluid path 18k of the packer 15b through the fluid tube 14c, the fluid path 18k of the packer 15c, and the inflow/outflow hole 18p, and flows between the peripheral surface of the frame 18c and the rubber 19 covering this peripheral surface. flow into Further, the fluid flows from the fluid path 18k of the packer 15c through the fluid tube 14a, the fluid path 18k of the packer 15a, and the inlet/outlet holes 18p, and flows between the peripheral surface of the frame 18a and the rubber 19 covering this peripheral surface. flow into

Then, the fluid expands the rubber 19 of each packer 15a, 15b, 15c away from the peripheral surface of the frame 18a, 18b, 18c and presses it against the inner peripheral surface of the freezing tube 11, whereby the packers 15a, 15b, 15c It expands and the inside of the freezing tube 11 is closed. That is, one section Xa in the freezing tube 11 is blocked by the packers 15a and 15c, and the other section Xb is blocked by the packers 15b and 15c. The supply pipes 12a, 12b, 12c communicate with the blocked section Xa, and the recovery pipe 13 communicates with the blocked section Xb.

In the next circulation freezing process, the coolant cooled by the cooler 42 is supplied to the supply pipe 12b. Then, as shown by arrows in FIG. 10(a), the coolant flows from the supply pipe 12b to the supply passage 18i of the packer 15b, the supply pipe 12c, the supply passage 18i of the packer 15c, the supply pipe 12a, and the supply passage of the packer 15a. 18 i to the closed section Xa in the freezing tube 11 . Also, the coolant flows from the blocked section Xa through the branch freezing pipe 31 into the blocked section Xb inside the freezing pipe 11 . The cold heat of the coolant in the closed sections Xa and Xb and the branch freezing pipe 31 is transmitted to the filling material in the sealing pipes 7 and 8 and the surrounding ground via the freezing pipe 11 and the shield pipes 7 and 8. This cools the infill and the ground.

The coolant deprived of cold heat in the closed sections Xa and Xb and the branch freezing pipe 31 is recovered by the cooler 42 through the recovery passage 18j of the packer 15b and the recovery pipe 13 . After being cooled by the cooler 42 , the coolant is again supplied to the closed sections Xa and Xb in the freezing pipe 11 and the branch freezing pipe 31 , where it is deprived of cold heat, and then sent to the cooler 42 . be recovered. In this way, by continuing the circulation of the coolant between the cooler 42, the blocked sections Xa and Xb in the freezing pipe 11, and the branch freezing pipe 31 for a predetermined period of time, the blocked sections Xa and Xb and the branch freezing pipe The filler and ground around 31 are frozen.

In the next shrinking process, the fluid inside each rubber 19 of the packers 15a, 15b, 15c is forced through the inflow and outflow holes 18p of the frames 18a, 18b, 18c, the fluid passages 18k, and the fluid tubes 14a, 14b, 14c to the outside. Each packer is shrunk in the order of packer 15a→15c→15b.

In the next moving step, the rear end of the wire rod 16b drawn out from the freezing tube 11 is pulled by the pulling machine 48, thereby moving the supply tubes 12a, 12b, 12c, the recovery tube 13, the fluid tubes 14a, 14b, 14c, and the packer. 15a, 15b, and 15c are moved within the freezing tube 11 in the axial direction (to the right in FIG. 10) by a predetermined distance. Then, the packer 15a is placed on the front side of one section Xa in the freezing tube 11 including the branch point between the adjacent branch freezing tube 31 and the freezing tube 11 . In addition, the packer 15c is arranged on the rear side of the one section Xa and on the front side of the other section Xb in the freezing tube 11 including the connection point between the branch freezing tube 31 and the freezing tube 11 . Furthermore, the packer 15b is arranged on the rear side of the other section Xb.

After that, the expansion process, the circulation freezing process, the contraction process, and the movement process are sequentially and repeatedly executed as described above, thereby freezing the ground around the freezing pipe 11 and the branch freezing pipe 31 for each predetermined section. . Further, in each freezing tube 11 installed in each shielding tube 7, 8, the above-described steps are similarly executed to freeze the ground G around each shielding tube 7, 8, and freeze the frozen soil wall 6. form (FIGS. 1 and 2).

According to the above-described second embodiment, by circulating the coolant in the one section Xa and the other section Xb blocked by the packers 15a, 15b, and 15c in the freezing pipe 11 and the branch freezing pipe 31 communicating with them, You can expand the freezing range of the ground that is frozen by cooling with coolant. In addition, since both ends of the branch freezing pipe 31 are connected to the same freezing pipe 11, the freezing range of the ground to be frozen by the coolant supplied to the single freezing pipe 11 can be expanded. Therefore, the ground surrounding the shield tubes 7 and 8 can be evenly and efficiently frozen for each predetermined section. In addition, by reducing the number of freezing pipes 11 installed in the large-diameter shield pipes 7 and 8, the number of executions of each process can be reduced, and the work load can be reduced.

FIG. 11 is a diagram showing an installed state of the freezing tube unit 10b of the third embodiment. 11(a) shows the front end sides of the shield tubes 7 and 8, and FIG. 11(b) shows the rear end sides of the shield tubes 7 and 8. As shown in FIG. In the third embodiment, as in the second embodiment, the freezing tubes 11 are installed on the inner peripheral surfaces of the shield tubes 7 and 8, and a plurality of branch freezing tubes 32 are connected to each freezing tube 11. The shape of 32 is different from the branch freezing tube 31 (FIG. 9) of the second embodiment. In FIG. 11, some branch freezing tubes 32 are illustrated.

The branch freezing tube 32 branches from a predetermined position of the freezing tube 11 and extends along the inner peripheral surfaces of the shield tubes 7 and 8 in a direction perpendicular to the axial direction of the shield tubes 7 and 8; It extends in a direction parallel to the tube axis direction. The branch freezing pipe 32 is connected to the freezing pipe 11 at a position different from the branch position so as to merge with the freezing pipe 11 . The freezing tube 11 and branch freezing tube 32 are fixed to the inner peripheral surfaces of the shield tubes 7 and 8 . The above points are the same as the branch freezing tube 31 of the second embodiment, but the branch freezing tube 32 of the third embodiment extends only on one side of the freezing tube 11 in the tube radial direction. In addition, the distance between the branch point and connection point (merge point) of the branch freezing tube 32 in the freezing tube 11 is shorter than the length of the portion of the branch freezing tube 32 parallel to the tube axis of the freezing tube 11 .

Inside the freezing tube 11 , a packer 15 a is arranged on the front side of one section Xa including the branch point between the freezing tube 11 and the branch freezing tube 32 . A packer 15c is arranged between the branch point and the connection point (joint point) of the freezing tube 11 and the branch freezing tube 32 . Furthermore, a packer 15b is arranged behind the other section Xb in the freezing tube 11 . The distance between the packer 15c and the packer 15b is approximately the same as the length of the portion of the branch freezing tube 32 parallel to the tube axis of the freezing tube 11 .

Supply pipes 12a, 12b, 12c, recovery pipe 13, fluid pipes 14a, 14b, 14c, wire rods 16a, 16b, etc. are inserted into freezing pipe 11 in the same manner as in the second embodiment shown in FIG. (illustration omitted). The connection state between these and the packers 15a, 15b, and 15c is also the same as in the second embodiment.

In the third embodiment as described above, by circulating the coolant in the one section Xa and the other section Xb blocked by the packers 15a, 15b, and 15c in the freezing tube 11 and the branch freezing tube 32, Can increase the area of ground that can be cooled and frozen. In addition, since both ends of the branch freezing pipe 32 are connected to the same freezing pipe 11, the range of the ground to be cooled and frozen by the coolant supplied to the single freezing pipe 11 can be expanded. Therefore, the ground surrounding the shield tubes 7 and 8 can be evenly and efficiently frozen for each predetermined section. In addition, the number of freezing pipes 11 installed in the shield pipes 7 and 8 can be reduced, and the number of executions of each process can be reduced, making it possible to reduce the construction burden.

FIG. 12 is a diagram showing an installed state of the freezing tube unit 10c of the fourth embodiment. 12(a) shows the rear end sides of the shield tubes 7 and 8, and FIG. 12(b) shows the front end sides of the shield tubes 7 and 8. As shown in FIG. In the fourth embodiment, one of the positions of the inner peripheral surfaces of the shield tubes 7 and 8 corresponding to the outer peripheral side and the inner peripheral side of the outer shell shield 1' (FIG. 2) of the underground structure 1 is frozen. A tube 11a is installed, and a freezing tube 11b is installed at the other position. A plurality of branch freezing tubes 33a and 33b are connected to the freezing tubes 11a and 11b at predetermined intervals in the axial direction of the shield tubes 7 and 8, respectively. FIG. 12 shows some branch freezing tubes 33a and 33b.

Each branch freezing tube 33a, 33b is branched from a predetermined position of each freezing tube 11a, 11b, and is perpendicular to the axial direction of the shield tubes 7, 8 along the inner peripheral surface of the shield tubes 7, 8. and in a direction parallel to the tube axis direction. A branch freezing pipe 33a and a branch freezing pipe 33b facing each other in the pipe radial direction of the shield pipes 7 and 8 are connected to each other by a relay pipe 34 provided so as to cross the shield pipes 7 and 8. As shown in FIG. The branch freezing pipes 33a, 33b and the relay pipe 34 communicate with each other. That is, the branch freezing pipes 33a and 33b connected by the relay pipe 34 are branched from one of the freezing pipes 11a and 11b and connected to the other. The freezing tubes 11a and 11b and the branch freezing tubes 33a and 33b are fixed to the inner peripheral surfaces of the shield tubes 7 and 8, respectively. An outer peripheral surface of the relay pipe 34 is covered with a heat insulating material 35 .

FIG. 13 is a cross-sectional view of the freezing tube unit 10c of the fourth embodiment. In FIG. 13, (a) shows the vicinity of the branch point between the freezing tube 11a and the branch freezing tube 33a, and (b) shows the vicinity of the branch point between the freezing tube 11b and the branch freezing tube 33b.

As shown in FIGS. 13(a) and 12, a packer 15d is arranged on the forward side of one section Xc in the freezing tube 11a including the branching point between the freezing tube 11a and the branch freezing tube 33a. A packer 15c is arranged on the rear side of the one section Xc.

As shown in FIG. 13(a), the tip of a cylindrical frame 18d provided in the packer 15d is closed. A fluid path 18k is formed in the frame 18d. The front end of the fluid pipe 14a is connected to the rear end of the frame 18d so as to communicate with the fluid passage 18k. A gap between the fluid path 18k of the frame 18d and the fluid pipe 14a is hermetically sealed by a sealing member (not shown).

A supply channel 18i and a fluid channel 18k are formed in the frame 18c of the packer 15c. A rear end portion of the fluid pipe 14a is connected to the front end portion of the frame 18c so as to communicate with the fluid passage 18k. The tip of the supply path 18i of the frame 18c is open. The front end of the supply pipe 12b is connected to the rear end of the frame 18c so as to communicate with the supply path 18i. That is, the supply pipe 12b communicates with one section Xc in the freezing pipe 11a via the supply path 18i of the frame 18c. A front end portion of the fluid pipe 14b is connected to the rear end portion of the frame 18c so as to communicate with the fluid passage 18k. A gap between the supply channel 18i of the frame 18c and the supply pipe 12b and a gap between the fluid channel 18k and the fluid pipes 14a and 14b are hermetically sealed by sealing members (not shown).

As shown in FIGS. 13(b) and 12, a packer 15d is arranged on the other side of the other section Xd in the freezing tube 11b including the branch point between the freezing tube 11b and the branch freezing tube 33b. A packer 15e is arranged on the rear side of the other section Xd.

As shown in FIG. 13, the structure of the packer 15d inside the freezing tube 11b is the same as the structure of the packer 15 inside the freezing tube 11a. The tip of the fluid tube 14a is connected to the rear end of the packer 15d inside the freezing tube 11b.

As shown in FIG. 13(b), a recovery path 18j and a fluid path 18k are formed in a cylindrical frame 18e provided in the packer 15e. A rear end portion of the fluid pipe 14a is connected to the front end portion of the frame 18e so as to communicate with the fluid passage 18k. The tip of the recovery path 18j of the frame 18e is open. A distal end portion of the recovery pipe 13 is connected to the rear end portion of the frame 18e so as to communicate with the recovery path 18j. That is, the recovery pipe 13 communicates with another section Xd in the freezing pipe 11b via the recovery path 18j of the frame 18e. A front end portion of the fluid pipe 14b is connected to the rear end portion of the frame 18e so as to communicate with the fluid passage 18k. A gap between the recovery path 18j of the frame 18e and the recovery tube 13 and a gap between the fluid path 18k and the fluid tubes 14a and 14b are hermetically sealed by sealing members (not shown).

Although not shown, wires 16a and 16b shown in FIG. 7 and the like are inserted into the freezing tubes 11a and 11b. Each packer 15c, 15d, 15e is formed with an insertion hole through which the wires 16a, 16b are inserted, similar to the insertion holes 18g, 18h shown in FIG. 7 and the like. The connection state and penetration state of the wires 16a and 16b and the packer 15d are the same as those of the packer 15a described above. The connection state and penetration state of the wire rods 16a, 16b and the packers 15c, 15e are the same as those of the packer 15b described above.

A rubber 19 is held on the peripheral surfaces of the frames 18c, 18d and 18e of the packers 15c, 15d and 15e. The holding structure of this rubber 19 is the same as that of the packers 15a, 15b, 15c of the first to third embodiments. As in the first to third embodiments, an elastic member 23 is provided between the rubber 19 and the frames 18c, 18d, and 18e. An inflow/outflow hole 18p is formed.

In the same procedure as in the first embodiment described above (see FIG. 7), the lead-out portion of the wire rod 16a from the freezing tube 11a is pulled by the pulling machine 48, thereby inserting the supply tube 12b and the fluid tubes 14a, 14b into the freezing tube 11a. , packers 15c, 15d, and wires 16a, 16b (not shown) are inserted and placed in the tube as shown in FIG. 13(a). Also, by pulling the lead-out portion of the wire 16a from the freezing tube 11b, the recovery tube 13, the fluid tubes 14a and 14b, the packers 15d and 15e, and the wires 16a and 16b (not shown) are inserted into the freezing tube 11b, These are placed in the tube as shown in FIG. 13(b). Then, after performing a filling process of filling the filling material into the shield tubes 7 and 8 and a filling process of filling the freezing tubes 11a and 11b with the antifreeze material, the packers 15c, 15d and 15e are expanded. Execute the process. Since this expansion process is basically the same as in the first embodiment and the second embodiment, detailed description thereof will be omitted.

By executing the expansion step, the packers 15c, 15d, and 15e expand, one section Xc in the freezing tube 11a is closed by the packers 15d and 15c, and the other section Xd in the freezing tube 11b is closed by the packers 15d and 15e. be. The supply pipe 12b communicates with the closed section Xc, and the recovery pipe 13 communicates with the closed section Xd.

In the next circulation freezing process, the coolant cooled by the cooler 42 is supplied to the supply pipe 12b. Then, the coolant is supplied from the supply pipe 12b through the supply path 18i of the packer 15c to the closed section Xc as indicated by the arrow in FIG. 13(a). Furthermore, the coolant flows from the blocked section Xc through the branch freezing pipe 33a, the relay pipe 34 (FIG. 12), and the branch freezing pipe 33b into the blocked section Xd in the freezing pipe 11b. The cold heat of the coolant in the closed sections Xc, Xd and the branch freezing pipes 33a, 33b is transmitted to the filler in the seal pipes 7, 8 and the surrounding ground, thereby cooling the filler and the ground.

The coolant deprived of cold heat in the closed sections Xc and Xd and the branch freezing pipes 33a and 33b is recovered by the cooler 42 through the recovery passage 18j of the packer 15e and the recovery pipe 13. After being cooled by the cooler 42, the coolant is again supplied to the closed sections Xc and Xd in the freezing pipes 11a and 11b and the branch freezing pipes 33a and 33b, and is deprived of cold heat there. It is recovered to cooler 42 . In this way, by continuing the circulation of the coolant between the cooler 42, the blocked sections Xc and Xd in the freezing pipes 11a and 11b, and the branch freezing pipes 33a and 33b for a predetermined time, the blocked section The filling material and the ground around Xc, Xd and branch freezing pipes 33a, 33b are frozen.

In the next shrinking step, the packers 15c, 15d, and 15e are shrunk by exhausting the fluid inside the rubber 19 of each packer to the outside through the inflow/outlet hole 18p, the fluid passage 18k, and the fluid pipe 14b. .

In the next moving step, the rear ends of the wire rods 16b (not shown) drawn out from the freezing pipes 11a and 11b are pulled by the pulling machine 48 in the same manner as described above, thereby moving the supply pipe 12b, the recovery pipe 13, and the fluid pipe 14b. , and packers 15c, 15d, and 15e are moved in the axial direction of the freezing tubes 11a and 11b (to the right in FIG. 13) by a predetermined distance. Then, the packer 15d is arranged on the front side of one section Xc in the freezing tube 11a including the branching point of the adjacent branch freezing tube 33a and the freezing tube 11a, and the packer 15c is arranged on the rear side of the one section Xc. do. In addition, the packer 15d is arranged on the front side of the other section Xd in the freezing tube 11b including the branch point of the adjacent branch freezing tube 33b and the freezing tube 11b, and the packer 15e is arranged on the rear side of the other section Xd. do.

After that, the expansion process, the circulation freezing process, the contraction process, and the movement process are sequentially and repeatedly executed as described above, thereby the ground surrounding the freezing pipes 11a and 11b and the branch freezing pipes 33a and 33b is divided into predetermined sections. let it freeze. Further, in each of the freezing tubes 11a and 11b installed in each of the shield tubes 7 and 8, the steps described above are similarly executed to freeze the ground G around each of the shield tubes 7 and 8, thereby forming frozen soil walls. 6 (FIGS. 1 and 2).

According to the fourth embodiment described above, a plurality of branch freezing pipes 33a and 33b are connected to the freezing pipes 11a and 11b installed in the shield pipes 7 and 8, respectively, and the opposing branch freezing pipes 33a and 33b are connected by the relay pipe 34. Connected. A supply pipe 12b, fluid pipes 14a, 14b, and packers 15d, 15c are inserted into one freezing pipe 11a, and a recovery pipe 13, fluid pipes 14a, 14b, and packers 15d, 15e are inserted into the other freezing pipe 11b. is inserted. The coolant is circulated through the blocked section Xc of one freezing pipe 11a, the branch freezing pipes 33a and 33b, and the blocked section Xd of the other freezing pipe 11b.

Therefore, the coolant is circulated in the one section Xc and the other section Xd blocked by the packers 15c, 15d, and 15e in the freezing pipes 11a and 11b and the branch freezing pipes 33a and 33b, and the ground to be frozen with this coolant is It can extend the freezing range. In addition, since the number of tubes to be inserted into each freezing tube 11a, 11b can be reduced, it is possible to easily insert and move tubes and packers into each freezing tube 11a, 11b.

In the above-described embodiment, the freezing pipes 11, 11a, 11b are installed in the shield pipes 7, 8 buried in the ground. may be set.

14 and 15 are diagrams showing other construction examples of the underground structure 71. FIG. 14 shows a horizontal section of the underground structure 71, and FIG. 15 shows a vertical section of the underground structure 71. As shown in FIG. The underground structure 71 is a tunnel constructed in the ground G.

To construct the underground structure 71, first, as shown in FIG. 14(a), a plurality of vertical shafts 72, 73 are constructed in the ground G at a predetermined depth. Next, using the frozen pipe 11c that also functions as a horizontal boring pipe, for example, the ground G is excavated horizontally from one vertical shaft 72 toward the other vertical shaft 73, and the frozen pipe 11c is inserted into the ground G. Install. At this time, as shown in FIG. 15(a), a plurality of freezing pipes 11c are annularly installed at predetermined intervals on the ground G between the plurality of shafts 72 and 73. As shown in FIG.

Then, a freezing method is performed to freeze the ground G around each freezing pipe 11c. This freezing method uses the freezing tube unit 10 (the freezing tube 11 is replaced by the freezing tube 11c) of the first embodiment shown in FIGS. 5 to 8 and the equipment shown in FIG. do in As a result, in the ground G between the vertical shafts 72 and 73, a ring-shaped frozen earth wall 76 having high strength and water stopping performance is formed for each predetermined section.

After that, as shown in FIGS. 14(b) and 15(b), the unfrozen ground G inside the frozen soil wall 76 is excavated, and the lining body 79 is assembled into a cylindrical shape. At this time, since the ground G outside the frozen soil wall 76 does not collapse and groundwater does not enter the inside of the frozen soil wall 76, excavation and assembling of the lining body 79 can be safely performed. Thereby, the underground structure 71 communicating with the plurality of shafts 72 and 73 can be reliably constructed.

FIG. 16 is a cross-sectional view of a freezing tube unit 10d according to the fifth embodiment. 16(a) and 16(b) have cross sections that are different by 90° around the tube axis of the freezing tube 11d provided in the freezing tube unit 10d.

The freezing pipe 11d is installed in the ground G in the vertical direction. The tip of the freezing tube 11d (lower end in FIG. 16) is closed in advance. A supply pipe 12b, a fluid pipe 14b, a wire rod 16b, and a packer 15a are inserted into the freezing pipe 11d. The rear end of the freezing tube 11d (upper end in FIG. 16) is exposed above the ground and closed with a closing member 29. As shown in FIG.

The closing member 29 is formed with a plurality of through holes 29h, 29i, 29j, and 29k. As shown in FIG. 16(a), the distal end of the recovery tube 13 is connected to the closing member 29 so as to communicate with the through hole 29h. In other words, the collection tube 13 communicates with the inside of the freezing tube 11d near the rear end of the freezing tube 11d. A rear end portion of the recovery pipe 13 is connected to a relay branch pipe 61 (FIG. 3). In the example of FIG. 16, the recovery tube 13 is not inserted into the freezing tube 11d. may be inserted.

As shown in FIGS. 16(a) and 16(b), the supply pipe 12b, the fluid pipe 14b, and the wire rod 16b are inserted through the through holes 29i, 29j, and 29k. The gaps between the through holes 29i, 29j, 29k and the supply pipe 12b, the fluid pipe 14b, and the wire rod 16b are airtightly sealed by sealing members (not shown).

A frame 18a of the packer 15a is formed with a supply channel 18i (FIG. 16(a)), a fluid channel 18k (FIG. 16(b)), and an insertion hole 18h (FIG. 16(b)). As shown in FIG. 16(a), the front end of the supply pipe 12b is connected to the rear end of the frame 18a so as to communicate with the supply path 18i. One end of the supply path 18i is open so as to look inside the freezing tube 11d. The rear end of the supply pipe 12b is connected to a relay branch pipe 60 (FIG. 3) outside the freezing pipe 11d.

Further, as shown in FIG. 16(b), the rear end portion of the frame 18a is connected to the front end portion of the fluid pipe 14b so as to communicate with the fluid passage 18k. The fluid path 18k is closed on the distal end side of the frame 18a. The rear end of fluid tube 14b is connected to a fluid supply 47 (FIG. 3) external to freeze tube 11d.

Further, as shown in FIG. 16(b), the tip of the wire rod 16b is inserted through the insertion hole 18h of the frame 18a. The tip of the wire 16b is connected (fixed) to the frame 18a. The insertion hole 18h is closed on the distal end side of the frame 18a. The rear end of the wire rod 16b is connected to a traction machine 48 (FIG. 3) outside the freezing tube 11d.

A rubber 19 is held on the peripheral surface of the frame 18a by holding members 20a, 20b, 21a, and 21b. In addition, an inlet/outlet hole 18p communicating with the fluid path 18k is formed in the peripheral surface of the frame 18a. The inflow/outflow hole 18p is covered with a rubber 19. As shown in FIG. Between the rubber 19 and the frame 18a, an elastic member is provided for contracting the packer 15a by pulling the rubber 19 toward the peripheral surface of the frame 18a by sliding the slider 20b toward the flange portion 18y of the frame 18a. A member 23 is provided.

FIG. 17 is a diagram showing one step of the freezing method using the freezing pipe unit 10d. FIG. 17 shows a cross-sectional view of the same plane as FIG. 16(b).

In the freezing method using the frozen pipe unit 10d, first, as shown in FIGS. 16 and 17, the frozen pipe 11d is installed in the ground G (installation step). Next, the packer 15a, the wire rod 16b, the supply pipe 12b, and the fluid pipe 14b are inserted into the freezing pipe 11d (insertion step). At this time, as shown in FIG. 17, each member is once inserted so that the packer 15a is positioned near the tip of the freezing tube 11d. Then, by pulling the wire rod 16 with the traction machine 48 (FIG. 3), as shown in FIG. Each member is moved in the axial direction of the freezing tube 11d (moving step). At this time, the supply pipe 12b and the fluid pipe 14b are also pulled so that the supply pipe 12b and the fluid pipe 14b do not loosen in the freezing pipe 11d. Also, the recovery tube 13 is connected to the rear end of the freezing tube 11d.

Next, the fluid supplied from the fluid supply source 47 (FIG. 3) is caused to flow into the inside of the packer 15a (the fluid path 18k, the inflow/outflow hole 18p, and between the frame 18a and the rubber 19) through the fluid pipe 14b, The rubber 19 of the packer 15a is expanded so as to block the inside of the freezing tube 11d (expansion step). As a result, as shown in FIG. 16(a), a closed section Xs is formed above the packer 15a in the freezing tube 11d. Next, the coolant cooled by the cooler 42 (FIG. 3) is blocked from the vicinity of the packer 15a in the freezing pipe 11d through the pipe 57 and the relay branch pipe 60 in FIG. 3 and the supply pipe 12b in FIG. Supply to section Xs. Then, the coolant in the closed section Xs is circulated so as to be recovered from the vicinity of the rear end of the frozen pipe 11d to the cooler 42 through the recovery pipe 13, the relay branch pipe 61 and the pipe 59 in FIG. to freeze the ground G around the closed section Xs (circulation freezing step). In FIG. 16(a), the frozen portion of the ground G is indicated by cross hatching.

After freezing the ground G around the closed section Xs, the circulation of the coolant is stopped, and the fluid inside the packer 15a (between the frame 18a and the rubber 19) is allowed to flow out through the fluid pipe 14b. , contract the rubber 19 of the packer 15a (contraction step). Then, by removing the closing member 29 from the rear end portion of the freezing tube 11d and pulling the wire 16b, the supply tube 12b, the fluid tube 14b, the wire 16b, and the packer 15a are extracted from the inside of the freezing tube 11d and collected. do. In addition, the recovery tube 13 is also recovered.

FIG. 18 is a cross-sectional view of a freezing tube unit 10e according to the sixth embodiment. Figs. 18(a) and 18(b) have cross sections that differ by 90° around the tube axis of the freezing tube 11d provided in the freezing tube unit 10e.

The freezing pipe 11d is installed in the ground G in the vertical direction. The tip of the freezing tube 11d is closed in advance. Supply pipes 12a and 12b, a recovery pipe 13, a fluid pipe 14b, a wire rod 16b, and a packer 15b are inserted into the freezing pipe 11d. A rear end portion of the freezing tube 11 d is exposed above the ground and closed by a closing member 29 . Through holes 29h, 29i, 29j, and 29k formed in the closing member 29, the recovery pipe 13, the supply pipe 12b, the fluid pipe 14b, and the wire rod 16b are inserted, respectively.

The frame 18b of the packer 15b includes a supply channel 18i (FIG. 18(a)), a recovery channel 18j (FIG. 18(a)), a fluid channel 18k (FIG. 18(b)), and an insertion hole 18h (FIG. 18(b). )) are formed. As shown in FIG. 18A, the rear end of the supply pipe 12a is connected to the front end of the frame 18b (the lower end in FIG. 18) so as to communicate with the supply path 18i. The supply pipe 12a has a predetermined length and an open end. The front end of the supply pipe 12b is connected to the rear end of the frame 18b (upper end in FIG. 18) so as to communicate with the supply path 18i. The rear end of the supply pipe 12b is connected to a relay branch pipe 60 (FIG. 3) outside the freezing pipe 11d.

Further, as shown in FIG. 18(a), the front end of the recovery tube 13 is connected to the rear end of the frame 18b so as to communicate with the recovery path 18j. The recovery path 18j is opened at the tip of the frame 18b so as to face the inside of the freezing tube 11d. The rear end of the recovery pipe 13 is connected to a relay branch pipe 61 (FIG. 3) outside the freezing pipe 11d.

Further, as shown in FIG. 18(b), the front end of the fluid pipe 14b is connected to the rear end of the frame 18b so as to communicate with the fluid passage 18k. The fluid path 18k is closed on the distal end side of the frame 18b. The rear end of fluid tube 14b is connected to a fluid supply 47 (FIG. 3) external to freeze tube 11d.

Further, as shown in FIG. 18(b), the tip portion of the wire rod 16b is inserted through the insertion hole 18h of the frame 18a. The tip of the wire rod 16b is connected (fixed) to the frame 18b. The insertion hole 18h is closed on the distal end side of the frame 18b. The rear end of the wire rod 16b is connected to a traction machine 48 (FIG. 3) outside the freezing tube 11d.

A rubber 19 is held by holding members 20a, 20b, 21a, and 21b on the peripheral surface of the frame 18b. In addition, an inlet/outlet hole 18p communicating with the fluid path 18k is formed in the peripheral surface of the frame 18b. The inflow/outflow hole 18p is covered with a rubber 19. As shown in FIG. An elastic member 23 is provided between the rubber 19 and the frame 18b to pull the rubber 19 toward the peripheral surface of the frame 18b via the slider 20b to contract the packer 15b.

FIG. 19 is a diagram showing one step of the freezing method using the freezing pipe unit 10e. FIG. 19 shows a cross-sectional view of the same plane as FIG. 18(b).

In the freezing construction method using the frozen pipe unit 10e, first, as shown in FIGS. 18 and 19, the frozen pipe 11d is installed in the ground G (installation step). Next, the packer 15b, the wire 16b, the supply tubes 12a and 12b, the recovery tube 13, and the fluid tube 14b are inserted into the freezing tube 11d (insertion step). At this time, as shown in FIG. 19, for example, each member is once inserted so that the tip of the supply pipe 12a is positioned near the tip of the freezing pipe 11d. Then, by pulling the wire rod 16b with the traction machine 48 (Fig. 3), each packer 15b is positioned near the top of a predetermined range in the ground G to be frozen, as shown in Fig. 18(b). The member is moved in the axial direction of the freezing tube 11d (moving step). At this time, the supply pipes 12a and 12b, the recovery pipe 13, and the fluid pipe 14b are also pulled so that they do not loosen in the freezing pipe 11d.

Next, the fluid supplied from the fluid supply source 47 (FIG. 3) is caused to flow into the inside of the packer 15b (the fluid path 18k, the inlet/outlet hole 18p, and between the frame 18b and the rubber 19) through the fluid pipe 14b, The rubber 19 of the packer 15b is expanded so as to block the inside of the freezing tube 11d (expansion step). As a result, as shown in FIG. 18(a), a closed section Xt is formed below the packer 15b in the freezing tube 11d. Next, the coolant cooled by the cooler 42 (FIG. 3) is passed through the pipe 57 and relay branch pipe 60 in FIG. 3 and the supply pipes 12a and 12b in FIG. Supply to the closed section Xt. Then, the coolant in the closed section Xt is circulated so as to be recovered from the vicinity of the packer 15b in the freezing pipe 11d to the cooler 42 through the recovery pipe 13, the relay branch pipe 61 and the pipe 59 in FIG. to freeze the ground G around the closed section Xt (circulation freezing step). In FIG. 18(a), the frozen portion of the ground G is indicated by cross hatching.

After freezing the ground G around the closed section Xt, the circulation of the coolant is stopped, and the fluid in the packer 15b is discharged through the fluid pipe 14b to contract the packer 15b (contraction step). By removing the closing member 29 from the rear end of the freezing tube 11d and pulling the wire 16b, the supply tubes 12a and 12b, the recovery tube 13, the fluid tube 14b, the wire 16b, and the packer 15b are removed from the inside of the freezing tube 11d. Pull them out and collect them.

According to the above-described fifth and sixth embodiments, the packers 15a and 15b inserted into predetermined positions in the freezing tube 11d are made to flow into the packers 15a and 15b through the fluid tube 14b to expand the packers 15a and 15b. One side of the tube 11d in the tube axis direction is blocked by packers 15a and 15b. Further, since the other side of the freezing tube 11d in the axial direction is closed in advance, closed sections Xs and Xt having a predetermined length are formed in the freezing tube 11d. Then, the coolant is circulated so that the coolant is supplied from one end side of the blocked sections Xs and Xt through the supply pipes 12a and 12b and recovered from the other end side of the blocked sections Xs and Xt through the recovery pipe 13. I am letting Therefore, the coolant can be spread all over the blocked sections Xs and Xt, and the ground G in a predetermined range around the blocked sections Xs and Xt can be evenly and efficiently frozen.

In addition, even after the frozen pipe 11d is installed in the ground G, the packers 15a and 15b inside the frozen pipe 11d can be pulled by pulling the wire rod 16b or the like depending on changes in geological features, surrounding environment, and other circumstances. can be changed to easily change the size and position of the closed sections Xs and Xt. Therefore, it is possible to freeze only a predetermined portion in the ground G, and it is possible to easily change the frozen portion and the frozen range in the ground G.

Various embodiments other than those described above can be employed in the present invention.

For example, in the above-described first to fourth embodiments, one circulation system for circulating the coolant in the frozen pipe is provided, and the surrounding ground is frozen for each span in the axial direction of the frozen pipe. Although shown, the invention is not so limited. For example, by inserting a supply pipe and a recovery pipe that constitute a circulation system into a plurality of freezing pipes so as to line up in the pipe radial direction of the freezing pipes, a plurality of circulation systems that circulate the coolant in the freezing pipes may be provided. . Then, the closed section in the freezing pipe that supplies the coolant in each circulation system may be shifted in the direction of the pipe axis, and the coolant may be circulated simultaneously in a plurality of circulation systems to simultaneously freeze the ground around a plurality of spans. . In this case, three or more packers may be arranged in the freezing tube at predetermined intervals in the pipe axis direction, and an appropriate number of supply pipes and recovery pipes may be connected to each packer.

In addition, in the above-described first to fourth embodiments, after the step of installing the freezing tube in the shield tube and the step of inserting the supply tube, recovery tube, fluid tube, packer, etc. into the freezing tube, Although an example in which the filler material filling process is executed has been shown, the filling process may be executed after the installation process and before the insertion process.

Further, in the above embodiments, an example was shown in which the packer was moved in the tube axis direction within the freezing tube by pulling the wire connected to the packer, but the present invention is not limited to this. For example, the wires may be omitted and the packer may be moved by pulling the supply, collection, or fluid tubes.

Further, in the first embodiment, after the wire 16a connected to the packer arranged at the most distal end of the freezing tube is changed in direction through a pulley 27 (FIG. 7) provided at the distal end of the freezing tube, An example is shown in which the supply tube, recovery tube, fluid tube, and packer are inserted into the freezing tube by leading out from the end and pulling the rear end of the wire 16a, but the present invention is not limited to this. do not have. For example, without providing the pulley 27, a wire rod connected to the packer arranged on the most distal side of the freezing pipe is inserted from the rear end of the freezing pipe, passed through the freezing pipe and led out from the distal end of the freezing pipe, and this wire rod The supply tube, collection tube, fluid tube, and packer may be inserted or moved within the cryo tube by pulling on the exit portion of the tube.

Further, in the above embodiment, an example was shown in which the rubber is easily contracted by the elastic force of the elastic member provided inside the rubber of the packer, but the present invention is not limited to this. For example, the packer may be forced to contract by sucking the fluid inside the rubber of the packer through a fluid tube or the like with a suction machine.

Further, in the above embodiments, an example in which the supply pipe, recovery pipe, or fluid pipe is fixed to the packer has been shown, but the present invention is not limited to this. For example, the frame of the packer is provided with a mechanism for slidably holding an inner tube such as a supply tube, a recovery tube, or a fluid tube in the axial direction of the freezing tube, so that the protrusion length of the inner tube from the packer can be varied. may

Further, in the above embodiments, the supply pipe and the coolant are supplied from the front end side of the freezing pipe to the closed section formed in the freezing pipe, and the coolant is recovered from the rear end side of the freezing pipe. Although an example of arranging the collection tube has been shown, the present invention is not limited to this. Conversely, the supply pipe and the recovery pipe are arranged so that the coolant is supplied from the rear end side of the freezing pipe to the closed section formed in the freezing pipe and the coolant is recovered from the front end side of the freezing pipe. may

Furthermore, in the above embodiments, the ground freezing construction method and frozen pipe unit of the present invention were applied to form a frozen soil wall in the surrounding ground when constructing a large-section underground structure at a great depth. Although examples have been given, the ground freezing construction method and frozen pipe unit of the present invention can also be applied to the formation of frozen soil walls for other uses.

7, 8 Shield tube (large diameter tube)
10, 10a, 10b, 10c, 10d, 10e freezing tube unit 11, 11a, 11b, 11c, 11d freezing tube 12a, 12b, 12c supply tube 13 recovery tube 14a, 14b, 14c fluid tube 15a, 15b, 15c, 15d, 15e packer 16a, 16b wire rod 17 holding truck 17a, 17b, 17c, 17d, 17e holding part 17t wheel 18a, 18b, 18c, 18d, 18e frame 19 rubber 20a sleeve (holding member)
20b slider (holding member)
21a, 21b retaining ring (retaining member)
23 Elastic member 27 Pulley 31, 32, 33a, 33b Branch freezing pipe 40 Refrigerator 47 Fluid supply source G Ground X, Xs, Xt Closed section Xa, Xc One section (closed section)
Xb, Xd other section (blocked section)

Claims (16)

An installation process of installing a frozen pipe in the ground;
an insertion step of inserting a supply tube, a recovery tube, a fluid tube, and a plurality of packers into the freezing tube and arranging the packers at predetermined positions in the axial direction of the freezing tube;
an expansion step of introducing fluid into the packers through the fluid tubes to expand the plurality of packers so as to occlude the freeze tubes;
The coolant is supplied through the supply pipe to the closed section in the freezing pipe formed by the expansion of the plurality of packers, and the coolant is recovered from the closed section through the recovery pipe, thereby removing the coolant. a circulation freezing step of freezing the ground around the closed section by circulating;
a contracting step of causing the fluid in the packer to flow out through the fluid tube to contract the plurality of packers;
a moving step of moving the supply pipe, the collection pipe, the fluid pipe, and the plurality of contracted packers in the pipe axis direction within the freezing pipe. In the ground freezing method according to claim 1,
After sequentially executing the installation step, the insertion step, the expansion step, the circulation freezing step, the shrinking step, and the moving step, the expansion step, the circulation freezing step, the shrinking step, and the moving step are performed. A ground freezing construction method characterized in that it is repeatedly executed in order. In the ground freezing method according to claim 1 or claim 2,
In the inserting step, the wire connected to the plurality of packers is inserted into the freezing tube, and at least one end of the wire is led out from the freezing tube,
In the inserting step or the moving step, by pulling the lead-out end of the wire, the supply pipe, the recovery pipe, the fluid pipe, and the plurality of packers are moved in the freezing pipe in the pipe axial direction. A ground freezing method characterized by moving to. In the ground freezing method according to any one of claims 1 to 3,
A ground freezing construction method characterized by performing a filling step of filling an antifreeze material into the frozen pipe at least before the expansion step. In the ground freezing method according to any one of claims 1 to 4,
In the installation step, one or more of the frozen pipes are installed in the large-diameter pipe buried in the ground in parallel with the axial direction of the large-diameter pipe,
After that, a filling step of filling a filling material into the large-diameter pipe is executed at least before the circulation freezing step. In the ground freezing method according to claim 5,
In the installing step, a branch freezing pipe branched from the freezing pipe, extending in a direction crossing or parallel to the pipe axis direction of the large diameter pipe, and connected to the freezing pipe, is connected to the large diameter pipe. Multiple units are installed at predetermined intervals in the pipe,
The packers are arranged on both sides of one section in the freezing pipe including the branching point of the freezing tube and the branch freezing tube, and another section in the freezing tube including the connection point of the freezing tube and the branch freezing tube. Place the packers on both sides of the
Next, in the expansion step, each packer is expanded to close the one section and the other section in the freezing tube,
After that, in the circulation freezing step, the coolant is circulated through the one section, the other section, and the branch freezing pipe within the freezing pipe. a freezing pipe installed in the ground;
a supply pipe for supplying coolant into the freezing pipe;
a recovery pipe for recovering the coolant in the freezing pipe;
a packer that closes the freezing tube;
a fluid pipe for flowing fluid into the packer,
With the freezing pipe closed by the packer, the coolant is supplied into the freezing pipe through the supply pipe, and the coolant is recovered from the freezing pipe through the recovery pipe, thereby circulating the coolant. In a freezing tube unit that freezes the ground around the freezing tube by causing
The packer is composed of a plurality of packers, expands when the fluid flows in through the fluid pipe to block the freezing pipe, and contracts when the fluid flows out through the fluid pipe,
The supply pipe, the recovery pipe, the fluid pipe, and the plurality of packers are inserted into the freezing pipe and arranged at predetermined positions in the axial direction of the freezing pipe,
The supply pipe communicates with the closed section in the vicinity of one of the packers in the closed section inside the freezing tube blocked by the plurality of packers,
the recovery pipe communicates with the closed section in the vicinity of the other packer in the closed section;
A freezing tube unit, wherein the supply tube, the recovery tube, the fluid tube, and the packer are movable in the tube axis direction in the freezing tube when the packer is contracted. In the cryo-tube unit of claim 7,
further comprising a holding carriage inserted into the freezing tube;
The holding carriage has a plurality of holding portions that individually hold the supply pipe, the recovery pipe, or the fluid pipe, and wheels that roll on the inner peripheral surface of the frozen pipe in the pipe axial direction. A cryo-tube unit characterized by: In the freezing tube unit according to claim 7 or claim 8,
A freezing tube unit, further comprising a wire connected to the packer, inserted into the freezing tube in the tube axial direction, and having at least one end led out from the freezing tube. In the cryo-tube unit of claim 9,
further comprising a pulley installed on the tip side of the freezing tube and on which the wire rod is hung,
One end of the wire rod whose direction is changed by the pulley is connected to the packer arranged on the most distal side of the freezing tube, and the other end is led out from the rear end side of the freezing tube. A freezing tube unit characterized by: In the freezing tube unit according to any one of claims 7 to 10,
A freezing tube unit, further comprising an elastic member provided in the packer and biasing the packer in a contraction direction. In the freezing tube unit according to any one of claims 7 to 11,
The packer is
a frame to which the supply pipe, the collection pipe, or the fluid pipe is connected;
a tubular rubber covering the peripheral surface of the frame;
a plurality of holding members each holding both ends of the rubber on the peripheral surface of the frame,
A freezing tube unit, wherein at least one of the plurality of holding members is movable in the axial direction of the frame. In the freezing tube unit according to any one of claims 7 to 12,
The frozen pipe is installed in a large-diameter pipe buried in the ground parallel to the axial direction of the large-diameter pipe,
a plurality of branch freezing tubes installed at predetermined intervals in the large-diameter tube, branching from the freezing tube, extending in a direction crossing or parallel to the axial direction of the tube, and connected to the freezing tube; further prepared,
The packers are arranged on both sides of a section in the freezing tube including the branch point of the freezing tube and the branch freezing tube, and are arranged in the freezing tube including the connection point of the branch freezing tube and the branch freezing tube. are arranged on both sides of the other section and close the one section and the other section by respectively expanding,
The supply pipe communicates with the one section,
The recovery pipe communicates with the other section,
A freezing pipe unit, wherein the coolant is circulated through the one section, the other section, and the branch freezing pipe through the supply pipe and the recovery pipe. A cryo-tube unit according to claim 13, wherein
A plurality of the freezing pipes are installed in the large diameter pipe,
The branch freezing tube is branched from one of the freezing tubes and connected to the other freezing tube,
the supply tube, the fluid tube, and the plurality of packers are inserted into the one freezing tube;
A freezing tube unit, wherein the recovery tube, the fluid tube, and the plurality of packers are inserted into the other freezing tube. An installation process of installing a frozen pipe in the ground;
an insertion step of inserting a supply tube, a fluid tube, and a packer into the freezing tube and arranging the packer at a predetermined position in the axial direction of the freezing tube;
an expansion step of causing a fluid to flow into the packer through the fluid pipe to expand the packer so as to block the previously unblocked one side of the freezing pipe in the pipe axial direction;
A coolant is supplied through the supply pipe to the closed section in the freezing pipe formed by the expansion of the packer, and the coolant is recovered from the closed section, thereby circulating the coolant to the closed section. A circulation freezing process that freezes the ground around the
a contracting step of causing the fluid in the packer to flow out through the fluid tube to contract the packer;
and a moving step of moving the supply pipe, the fluid pipe, and the contracted packer in the pipe axis direction within the freezing pipe. a freezing pipe installed in the ground;
a supply pipe for supplying coolant into the freezing pipe;
a recovery pipe for recovering the coolant in the freezing pipe;
a packer that closes the freezing tube;
a fluid pipe for flowing fluid into the packer,
With the freezing pipe closed by the packer, the coolant is supplied into the freezing pipe through the supply pipe, and the coolant is recovered from the freezing pipe through the recovery pipe, thereby circulating the coolant. In a freezing tube unit that freezes the ground around the freezing tube by causing
the supply tube and the fluid tube are inserted into the freezing tube while being connected to the packer;
The packer closes one side of the freezing tube that is not closed in advance in the axial direction of the freezing tube by the fluid flowing in through the fluid tube and expanding, thereby forming a closed section in the freezing tube. contracting due to the outflow of the fluid through the fluid tube;
In the closed section, the supply pipe communicates with the closed section near one end in the pipe axial direction, and the recovery pipe communicates with the closed section near the other end in the pipe axial direction. ,
A freezing tube unit, wherein the supply tube, the fluid tube, and the packer are movable in the tube axis direction in the freezing tube when the packer is contracted.

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