JP2021161787A - Ground freezing method, and freezing pipe unit - Google Patents

Abstract

To provide a ground freezing method and a freezing pipe unit which efficiently freeze a ground without unevenness and can easily change a freezing part and a freezing range of the ground.SOLUTION: A freezing pipe 11 is installed in the ground, and a plurality of packers 15a and 15 are arranged at a predetermined interval in the freezing pipe 11 in a state of being connected to supply pipes 12a and 12b, a recovery pipe 13 and fluid pipes 14a and 14b. A fluid is flowed into the packers 15a and 15b and is expanded, and then a cooling material is circulated through a blocking section X blocked by the packers 15a and 15b through the supply pipes 12a and 12b and the recovery pipe 13, and the ground around the blocking section X is frozen. Then, the fluid in the packers 15a and 15b is flowed and contracted, and then the supply pipes 12a and 12b, the recovery pipe 13, the fluid pipes 14a and 14b and the packers 15a and 15b are moved in a pipe axis direction in the freezing pipe 11. Steps from the expansion to the movement are repeatedly executed, and the ground around the freezing pipe 11 is sequentially frozen for each predetermined section.SELECTED DRAWING: Figure 5

Description

The present invention relates to a ground freezing method and a freezing pipe unit that freezes the surrounding ground by circulating a coolant through a freezing pipe installed in the ground.

A brine circulation method is used to freeze the ground around the freezing pipe by circulating the cooling material (brine) cooled by the refrigerator to the freezing pipe installed in the ground. be. In recent years, this ground freezing method stabilizes and stops water in the surrounding ground when constructing an underground structure with a large cross section at a large depth, as disclosed in Patent Documents 1 and 2, for example. It has been adopted as a protective worker.

The freezing pipe unit used in the brine circulation type ground freezing method includes a freezing 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 freezing pipe. One side (tip side) of the freezing tube is closed with a filler, and the other side is closed with a single packer. The packer is inserted in the perforated steel pipe, not in the frozen pipe. The tip of the supply pipe is arranged near the filler in the freezing pipe, and the tip of the recovery pipe is arranged near the packer. The middle part between the supply pipe and the recovery pipe is held by the packer, and the rear end part is connected to the refrigerator. Then, the coolant cooled by the refrigerator is supplied to the predetermined section in the freezing pipe through the supply pipe, and the coolant is circulated so as to collect the coolant from the predetermined section through the recovery pipe to the refrigerator. Freeze the ground around the specified section. On the contrary, there is also a construction method in which the tip end side of the freezing tube is closed with a packer (for example, Patent Document 4).

On the other hand, Patent Document 5 discloses a ground freezing method of 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. The freezing pipe unit used in this ground freezing method includes a pipe material made 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 the packer. The two inner tubes are connected to the packer. The packer, pumping pipe, and inner pipe are movable in the pipe material in the pipe axial direction. After locating the double packer near the injection hole provided at the predetermined position of the pipe material, compressed air is supplied from the air supply source into the double packer through one inner pipe to expand the double packer. , Both sides in the pipe axial direction are closed with a double packer with respect to the injection hole in the pipe material (see FIG. 4 of Patent Document 5). Alternatively, one side in the pipe axial direction with respect to the injection hole in the pipe material is closed with a single packer (see FIG. 5). Then, the liquefied carbon dioxide gas is supplied into the packer or the pipe material through the pumping pipe. Then, the liquefied carbon dioxide gas pushes up the rubber sleeve from the injection hole and injects it into the surrounding ground. The heat of vaporization of the injected liquefied carbon dioxide gas freezes the ground around the pipe material. The compressed air in the packer is exhausted through the other inner tube.

Japanese Unexamined Patent Publication No. 2019-31810 Japanese Patent No. 6257814 Japanese Unexamined Patent Publication No. 2005-344460 Japanese Unexamined Patent Publication No. 2019-183441 Japanese Unexamined Patent Publication 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 in the long internal space inside the freezing pipe at one time, the temperature distribution may occur and the surrounding frozen state may become uneven, and more cold heat is required at one time. There is also the problem of becoming. In addition, by continuing to circulate the coolant in the freezing pipe for a long period of time, there is a concern that an excessive amount of frozen soil will be created with respect to the frozen soil required for strengthening the stability of the ground and stopping water.

Further, as in Patent Document 3, for example, only a predetermined part in the ground is frozen according to the geology, or the frozen part or the freezing range in the ground is changed according to a change in the surrounding environment or other circumstances. In such cases, it is difficult to change the freezing location and freezing range after installing the freezing pipe in the ground.

An object of the present invention is to provide a ground freezing method and a freezing pipe unit capable of freezing the ground evenly and efficiently, and easily changing the freezing location and freezing range of the ground.

In the ground freezing method of the present invention, a freezing pipe is installed in the ground, and a supply pipe, a recovery pipe, a fluid pipe, and a plurality of packers are inserted into the freezing pipe, and the packer is inserted in the pipe axial direction of the freezing pipe. An insertion step of placing the fluid in a predetermined position, an expansion step of inflowing a fluid into the packer through a fluid tube and expanding a plurality of packers so as to block the freezing tube, and a freezing formed by the expansion of the plurality of packers. A circulation freezing step in which the cooling material is supplied to the closed section in the pipe through a supply pipe and the cooling material is recovered from the closed section through a recovery pipe to circulate the cooling material and freeze the ground around the closed section. A contraction step in which the fluid in the packer is discharged through the fluid pipe to contract a plurality of packers, and a movement step in which the supply pipe, the recovery pipe, the fluid pipe, and the contracted packers are moved in the axial direction in the freezing pipe. And include.

Further, the freezing pipe unit of the present invention includes a freezing pipe installed in the ground, a supply pipe for supplying a cooling material into the freezing pipe, a recovery pipe for collecting the cooling material in the freezing pipe, and a packer for closing the freezing pipe. And a fluid pipe that allows fluid to flow into the packer. With the freezing pipe blocked by the packer, the coolant is supplied into the freezing pipe through the supply pipe, and the coolant is collected from the freezing pipe through the recovery pipe to circulate the coolant and create the ground around the freezing pipe. Freeze. In the freezing tube unit of the present invention, the packer is composed of a plurality of packers, and expands when the fluid flows in through the fluid tube to block the freezing tube, and contracts when the fluid flows out through the fluid tube. The supply pipe, recovery pipe, fluid pipe, and a plurality of packers are inserted into the freezing pipe and placed at predetermined positions in the pipe axial direction of the freezing pipe. The supply pipe communicates with the closed section in the vicinity of one packer in the closed section in the frozen pipe closed by a plurality of packers, and the recovery pipe communicates with the closed section in the vicinity of the other packer in the closed section. Communicating. With the packer contracted, the supply pipe, recovery pipe, fluid pipe, and packer can move in the freezing pipe in the direction of the pipe axis.

According to the ground freezing method and the freezing pipe unit of the present invention as described above, a plurality of packers are arranged in the freezing pipe at predetermined intervals in the pipe axis direction, and fluid is allowed to flow into each packer through a fluid pipe to allow each packer to flow. By expanding, a closed section having a predetermined length is formed in the freezing tube. Then, by circulating the coolant through the supply pipe and the recovery pipe in this closed space, the coolant is spread all over the closed space, and the ground in the predetermined section around the closed space is surely 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 freezing pipe surrounded by the ground of the frozen predetermined section and the adjacent unfrozen ground, and then the expansion step and circulation described above are performed. The freezing step, the shrinking step, and the moving step are repeatedly executed in this order. As a result, even if the freezing pipe is installed over a long distance, it is possible to efficiently freeze a wide range of ground around the freezing pipe evenly and efficiently at predetermined sections. In addition, depending on the geology, changes in the surrounding environment, and other circumstances, the number of times the expansion process, circulation freezing process, contraction process, and movement process described above are repeated in order can be set, and the supply pipe and recovery pipe can be set inside the freezing pipe. , The fluid tube, and the moving length to move the packer can be changed, and the position where 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 part in the ground, and it is possible to easily change the frozen part and the freezing range in the ground. It becomes.

As described above, according to the ground freezing method and the freezing tube unit of the present invention, the ground can be frozen evenly and efficiently, and the freezing location and freezing range of the ground can be easily changed. Further, even when it is necessary to keep circulating the coolant in the freezing pipe for a long period of time, a part of the freezing pipe in the longitudinal direction can be cooled in a limited manner, so that excess frozen soil growth can be suppressed.

It is a figure which showed the construction example of the underground structure of a large cross section. It is a figure which showed the construction example of the underground structure of a large cross section. It is a facility block diagram of the ground freezing method of the brine circulation system. It is a figure which showed the freezing tube unit by 1st Embodiment of this invention. It is a cross-sectional view of the freezing tube unit of FIG. It is an enlarged view of the vicinity of the packer of FIG. It is sectional drawing of the tip part of the freezing tube of FIG. It is sectional drawing of the vicinity of the holding carriage of FIG. It is a figure which showed the freezing tube unit by the 2nd Embodiment of this invention. It is a cross-sectional view of the freezing tube unit of FIG. It is a figure which showed the freezing tube unit by the 3rd Embodiment of this invention. It is a figure which showed the freezing tube unit by 4th Embodiment of this invention. It is a cross-sectional view of the freezing tube unit of FIG. It is a figure which showed the other construction example of the underground structure. It is a figure which showed the other construction example of the underground structure. It is a figure which showed the freezing tube unit by the 5th Embodiment of this invention. It is a figure which showed one step of the freezing method using the freezing tube unit of FIG. It is a figure which showed the freezing tube unit by the 6th Embodiment of this invention. It is a figure which showed one step of the freezing method using the freezing tube unit of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each figure, the same parts or corresponding parts are designated by the same reference numerals.

First, an application example of the ground freezing method and the freezing pipe unit of the embodiment will be described.

1 and 2 are views showing a construction example of an underground structure 1 having a large cross section. FIG. 1 shows a horizontal cross section of the underground structure 1, and FIG. 2 shows a vertical cross section of the underground structure 1. In the case of this example, the underground structure 1 is a tunnel having a large cross section constructed before the construction of connecting the ramp tunnel 3 to the main tunnel 2 in which the vehicle travels is performed in the deep ground G.

First, as shown in FIG. 1A, a starting base 4 is constructed around a predetermined portion of the main tunnel 2. Further, a reach base 5 is constructed around another predetermined location of the main tunnel 2, and the ramp tunnel 3 is connected to the reach base 5. The distance from the starting base 4 to the reaching base 5 is, for example, several hundred meters or more.

Then, a plurality of shield pipes 7 and 8 are installed in a ring shape from the starting base 4 to the reaching base 5 by a known shield method (see FIG. 2). At this time, after installing a plurality of leading shield pipes 7, the trailing shield pipe 8 is dug while scraping a part of the pipe wall of the leading shield pipe 7, and the trailing shield pipe 7 is sandwiched between the leading shield pipes 7. 8 is installed. As a result, as shown in FIG. 2A, the leading shield pipe 7 and the trailing shield pipe 8 are alternately buried in the ground G around the tunnels 2 and 3, and the tunnel-shaped outer shell shield 1 'Is formed. Further, a part of the trailing shield tube 8 is in a state of biting into the leading shield tube 7.

Next, a freezing method is performed in which the ground G around the shield pipes 7 and 8 is frozen. 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 blocking performance is formed around the outer shell shield 1'.

Next, after excavating the inside of the shield pipes 7 and 8 to communicate the adjacent shield pipes 7 and 8, the shield pipes 7 and 8 are crossed as shown in FIGS. 2 (c) and 1 (c). As described above, the tubular lining body 9 is constructed. This completes the construction of the underground structure 1. After that, a predetermined work is carried out in the underground structure 1, and the 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 an equipment configuration diagram of the ground freezing method of the brine circulation method. The freezing tube units 10 are provided in an appropriate number, and are installed in the shield tubes 7 and 8 as shown in FIG. Details of the structure and function of the freezing tube unit 10 will be described later. The refrigerator 40 and the machine room are provided, for example, at the above-mentioned starting base 4 or reaching base 5. The refrigerator 40 includes a condenser 41, a cooler 42, and a compressor 43.

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

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

The fluid pipe 14b provided in the freezing pipe unit 10 is connected to a fluid supply source 47 such as a compressor. Further, the wire rods 16a and 16b provided in the freezing tube unit 10 are made of wires or the like and are connected to a traction 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. 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 pipe axis 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. 4 (c) is. , The perspective sectional view of the rear end side of the shield pipes 7 and 8 is shown. A plurality of freezing pipes 11 provided in the freezing pipe unit 10 are installed on the inner peripheral surfaces of the shield pipes 7 and 8 buried in the ground G as described above. The diameter of each of the shield tubes 7 and 8 is, for example, about 4 meters. The diameter of the freezing tube 11 is, for example, about 160 mm. Shielded tubes 7 and 8 are examples of the "large diameter tube" of the present invention.

FIG. 5 is a cross-sectional view of the freezing tube unit 10. 5 (a) and 5 (b) have cross sections that differ by 90 ° around the tube axis of the freezing tube 11. The supply pipes 12a and 12b, the recovery pipes 13, the fluid pipes 14a and 14b, the packers 15a and 15b, the wire rods 16a and 16b, and the holding carriage 17 are inserted into the freezing pipe 11. 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 of 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, the packers 15a and 15b have columnar 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 path 18i (FIG. 5A), a fluid path 18k (FIGS. 5B, 6), and insertion holes 18g, 18h (FIG. 7).

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

Further, the tip end portion of the fluid pipe 14a is connected to the rear end portion of the frame 18a so as to communicate with the fluid passage 18k (FIG. 5B). The gap between the fluid passage 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, supply passages 18i, recovery passages 18j, fluid passages 18k, and insertion holes 18g and 18h are formed in the frame 18b of the packer 15b arranged on the rear end side of the freezing pipe 11. ing. The rear end of the supply pipe 12a is connected to the tip of the frame 18b so as to communicate with the supply path 18i (FIG. 5A). The tip 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 via the supply path 18i of the packer 15b. The gap between the supply path 18i of the frame 18b and the supply pipes 12a and 12b is hermetically sealed by a sealing member (not shown).

The tip of the recovery pipe 13 is connected to the rear end 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 space X) between the packers 15a and 15b in the freezing tube 11 via the recovery path 18j. .. The gap between the recovery path 18j and the recovery pipe 13 is hermetically sealed by a sealing member (not shown).

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

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

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

The wire rod 16b is connected (fixed) to the frames 18a and 18b. The wire rod 16a is movable in the tube 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 sealed in a substantially airtight state by a sealing member (not shown). As shown in FIG. 3, the rear end portions of the wire rods 16a and 16b are led out from the rear end side of the freezing pipe 11 and connected to the towing machine 48.

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

Specifically, as shown in FIG. 6, one end (right side) of the rubber 19 of the packer 15a is sandwiched between the sleeve 20a attached to the peripheral surface of the frame 18a and the holding ring 21a attached to the sleeve 20a. ing. The sleeve 20a is fixed to the frame 18a with screws 22. The other end (left side) of the rubber 19 is sandwiched between a cylindrical slider 20b mounted on the peripheral surface of the frame 18a and a holding ring 21b mounted on the slider 20b. The slider 20b is not fixed to the frame 18a and can slide along the frame 18a in the pipe axis direction for a predetermined length. A flange portion 18y is formed at the tip end portion 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. Similarly, each end of the rubber 19 of the packer 15b is also held by the peripheral surfaces of the holding members 20a, 20b, 21a, 21b and the frame 18b.

Further, inflow / out holes 18p communicating with the fluid passage 18k are formed on the peripheral surfaces of the frames 18a and 18b (FIGS. 5 (b) and 6). The inflow / outflow hole 18p is covered with a rubber 19. An elastic member 23 is provided between the rubber 19 and the frames 18a and 18b. The elastic member 23 is composed of a coil spring, and by urging the slider 20b toward the flange portion 18y, the other end portion (the left end portion in FIG. 6 or the like) of the rubber 19 is pulled in the tube axis direction of the freezing tube 11. Then, the central portion of the rubber 19 is pulled toward the peripheral surface side of the frames 18a and 18b.

As shown in FIG. 7, the tip of the freezing tube 11 is closed by the 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 toward the tip end side of the frame 18a through the insertion hole 18g of the frame 18a of the packer 15a penetrates the through hole 24a of the cover 24, passes through the reel group 26 in the turn box 25, and passes through the pulley 27. Is hung on. Then, after the wire rod 16a is turned by the pulley 27, the wire rod 16a penetrates the through hole 24b of the cover 24 via the reel group 26 and is connected to the tip end portion of the frame 18a. The gap between the through holes 24a and 24b and the wire rod 16a is hermetically sealed by a sealing member (not shown).

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

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

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

First, as described above, before or after burying the shield pipes 7 and 8 in the ground G, a plurality of freezing pipes 11 are installed in the shield pipes 7 and 8 as shown in FIG. 4 (installation step). .. Specifically, in this installation process, freezing is performed at the positions of the inner peripheral surfaces of the shield pipes 7 and 8 corresponding to the outer peripheral side and the inner peripheral side of the outer shell shield 1'(FIG. 2) of the above-mentioned underground structure 1. The pipes 11 are installed parallel to the pipe axis direction of the shield pipes 7 and 8 and at predetermined intervals in the circumferential direction of the pipes. As a result, the freezing pipe 11 is installed in the ground G via the shield pipes 7 and 8.

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

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

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

Further, at the time of this pulling in, the supply pipe 12b, the recovery pipe 13, the fluid pipe 14b, and the wire rods 16a and 16b on the rear side of the packer 15b are held by an appropriate number of holding carts 17, and the holding carts 17 are also held by the freezing pipe 11. Insert inside.

As another example, even if an appropriate number of holding carriages 17 are inserted between the packers 15a and the packers 15b, the holding carriages 17 hold the supply pipes 12a, the fluid pipes 14a, and the wire rods 16a and 16b. good.

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

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

Next, the fluid supplied from the fluid supply source 47 is allowed to flow into the packers 15a and 15b through the fluid pipes 14a and 14b, and as shown in FIGS. 5A and 6B, the packers 15a and 15b (Expansion step). Specifically, in this expansion step, antifreeze, compressed air, or the like is introduced into the fluid tube 14b as a fluid from the fluid supply source 47. Then, as shown by an arrow in FIG. 5B, the fluid passes from the fluid tube 14b through the fluid path 18k of the packer 15b and the inflow / outflow hole 18p, and the peripheral surface of the frame 18b and the rubber 19 covering the peripheral surface. Inflow between and. Further, this fluid passes from the fluid passage 18k of the frame 18b through the fluid pipe 14a, the fluid passage 18k of the packer 15a and the inflow / outflow hole 18p, and the peripheral surface of the frame 18a and the rubber 19 covering the peripheral surface. It flows in between (Fig. 6 (a)).

Then, the fluid inflates the rubber 19 of the packers 15a and 15b so as to be separated from the peripheral surfaces of the frames 18a and 18b, and presses the rubber 19 against the inner peripheral surface of the freezing tube 11, so that the packers 15a and 15b expand and freeze. The tube 11 is in a closed state (FIGS. 5 (a) and 6 (b)).

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

By the above expansion step, as shown in FIG. 5A, a closed section X closed by the packers 15a and 15b is formed in the freezing tube 11. The supply pipes 12a and 12b communicate with the closed space X in the vicinity of the packer 15a. The recovery pipe 13 communicates with the closed space 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 is circulated so as to collect the coolant in the closed space X to the cooler 42 through the recovery pipe 13 to freeze the ground G around the closed space X of the freezing pipe 11 (circulation freezing). Process).

Specifically, in the circulation freezing step, first, the on-off valve 62 shown in FIG. 3 is opened, and the cooling material cooled by the cooler 42 is opened and closed with the pipe 57 and the relay branch pipe 60 by the pumping force of the circulation pump 46. It is supplied to the supply pipe 12b through the valve 62. Then, as shown by an arrow in FIG. 5A, the coolant is blocked in the vicinity of the packer 15a through the supply pipe 12b, the supply path 18i of the packer 15b, the supply pipe 12a, and the supply path 18i of the packer 15a. It is supplied to the section X. Then, the cooling heat of the cooling material in the closed section X passes through the freezing pipe 11 and the shield pipes 7 and 8 in which the freezing pipe 11 is installed, and the filler and the closed section X in the sealing pipes 7 and 8. The filler and the ground are cooled by being transmitted to the ground around the.

As shown by the arrow in FIG. 5A, the coolant deprived of cold heat in the closed section X passes through the recovery path 18j and the recovery pipe 13 of the packer 15b, and further with the on-off valve 62 shown in FIG. It is collected by the coolant 42 through the relay branch pipe 61 and the pipes 58 and 59. Then, the recovered coolant is cooled by the cooler 42 and then supplied again to the closed section X in the freezing pipe 11, where the cold heat is taken away and then recovered to the cooler 42. By continuing to circulate the coolant between the cooler 42 and the closed section X in the freezing pipe 11 for a predetermined time, the filler and the ground around the closed space X are frozen.

After freezing the ground around the closed space X, the circulation of the coolant is stopped, and then the fluid in the packers 15a and 15b is allowed to flow out through the fluid pipes 14a and 14b to contract the packers 15a and 15b ( Shrinkage process). Specifically, in this contraction step, the fluid between the peripheral surfaces of the frames 18a and 18b of the packers 15a and 15b and the rubber 19 is introduced into the inflow and outflow holes 18p of the frames 18a and 18b, the fluid passage 18k and the fluid tubes 14a and 14b. And, it is collected in the fluid supply source 47 and exhausted to the outside (see the arrow in FIG. 6C). As a result, the rubber 19 of the packers 15a and 15b is separated from the inner peripheral surface of the freezing tube 11, and the slider 20b is slid toward the flange portion 18y by the elastic force of the elastic member 23, so that the central portion of the rubber 19 is framed. The packers 15a and 15b are attracted to the peripheral surface side of the 18a and 18b, and the packers 15a and 15b are in a contracted state.

Even when the rubber 19 of the packers 15a and 15b is attracted to the peripheral surface side of the frames 18a and 18b as described above, one end of the rubber 19 of the packers 15a and 15b does not move because it is a fixed end. On the other hand, since the other end of the rubber 19 is a free end, it moves in the direction of the freezing tube 11 (see FIG. 6C). By contracting the packers 15a and 15b as described above, the blocked state in 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 and 12b, the recovery pipes 13, the fluid pipes 14a and 14b, and the packers 15a and 15b are predetermined in the freezing pipe 11 in the pipe axial direction. Move a distance (movement process). 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 frozen pipes by a distance equivalent to the length of the blockage section X in the freezing pipe 11 described above. It is moved to the rear end side of 11 (to the right in FIG. 5). As a result, for example, the packer 15a at the position shown in FIG. 5 moves to the position of the packer 15b shown in FIG. As a result, the moved supply pipes 12a and 12b, recovery pipes 13, fluid pipes 14a and 14b, and packers 15a and 15b are surrounded by 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 step and the moving step are executed to move the packers 15a, 15b and the like further to the rear end side of the freezing pipe 11 to freeze the next unfrozen ground.

In the same manner thereafter, by repeatedly executing the above-mentioned expansion step, circulation freezing step, contraction step, and moving step in this order, a wide range of ground G around the freezing pipe 11 installed over a long distance can be obtained. While moving the packers 15a, 15b, etc. in sequence, the packers are frozen at predetermined sections.

The above processing is executed for each freezing pipe 11 installed in each of the shield pipes 7 and 8, and as shown in FIGS. 1 and 2, a wide range of ground around each of the shield pipes 7 and 8 is performed. Freeze G. As a result, a frozen soil wall 6 having a predetermined strength and water blocking performance is formed around the outer shell shield 1'of the underground structure 1.

According to the first embodiment described above, a plurality of packers 15a and 15b are arranged in the freezing tube 11 at predetermined intervals in the pipe axis direction, and the packers 15a and 15b are expanded to form a predetermined size in the freezing tube 11. It forms a closed section X having a length. Then, the coolant is circulated through the supply pipes 12a and 12b and the recovery pipe 13 with respect to the closed space X and the cooler 42 of the refrigerator 40. Therefore, the coolant can be spread all over the closed space X, and the ground in a predetermined section around the closed space 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, and the packers 15a and 15b are contracted. Then, the supply pipes 12a and 12b, the recovery pipe 13, the fluid pipes 14a and 14b, and the packers 15a and 15b are moved in the freezing pipe 11 in the direction of the pipe axis to be unfrozen adjacent to the ground of the frozen predetermined section. It is arranged at a predetermined position in the freezing pipe 11 surrounded by the ground. Then, the expansion step, the circulation freezing step, the contraction step, and the moving step described above are repeatedly executed in this order. As a result, even if the freezing pipe 11 is installed over a long distance, it is possible to efficiently freeze a wide range of ground around the freezing pipe 11 evenly and efficiently for each predetermined section.

Further, after installing a plurality of freezing pipes 11 in a plurality of shield pipes 7 and 8 buried in the ground and filling the shield pipes 7 and 8 with a filler, the above-mentioned is described for each of the freezing pipes 11. The expansion step, the circulation freezing step, the contraction step, and the moving step are repeatedly executed in this order. As a result, the cold heat of the cooling material circulated in the closed section X in each freezing pipe 11 is transferred to the ground around the shield pipes 7 and 8 via the freezing pipe 11, the shield pipes 7 and 8, or the filler. This makes it possible to freeze the ground evenly and efficiently for each predetermined section.

Further, for the plurality of shield pipes 7 and 8, the work of freezing the surrounding ground, the work of excavating the inside, and the work of constructing the lining body 9 can be performed in parallel for each predetermined section. , It is possible to shorten the construction period required for the construction of the underground structure 1.

Further, in the above-described first embodiment, the wire rod 16a is inserted into the freezing pipe 11, and the pulley 27 in the turn box 25 attached to the tip of the freezing pipe 11 is hung with the wire rod 16a to change the direction. The wire rod 16a is led out from the rear end of the freezing tube 11. Further, 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 pipe 11 with the traction machine 48, the supply pipes 12a and 12b, the recovery pipe 13, the fluid pipes 14a and 14b, and the packers 15a and 15b are placed in the freezing pipe 11. It can be easily and reliably inserted to any position. Further, at the time of this insertion, the stress and stress applied to the supply pipes 12a and 12b, the recovery pipes 13 and the fluid pipes 14a and 14b, and the connecting portions of each of these pipes and the packers 15a and 15b are reduced to reduce the stress and stress applied to each pipe and the packer 15a and 15b. It is possible to prevent damage to the connecting portion.

Further, in the above-described first embodiment, the wire rod 16b is inserted into the freezing pipe 11 in a state of being connected to the packers 15a and 15b, and one end of the wire rod 16b is led out from the rear end portion of the freezing pipe 11. Then, by pulling one end of the wire rod 16b with the traction machine 48, the supply pipes 12a and 12b, the recovery pipes 13, the fluid pipes 14a and 14b, and the packers 15a and 15b are brought into the freezing pipe 11 at the rear end of the freezing pipe 11. It can be easily and surely moved to the side. Further, during this movement, it is possible to reduce stress and stress applied to the supply pipes 12a and 12b, the recovery pipes 13, the fluid pipes 14a and 14b, and the connecting portions of these pipes and the packers 15a and 15b. It is possible to prevent damage to pipes and connecting parts. Further, by adjusting the pull-out length of the wire rods 16a and 16b from the freezing pipe 11, the supply pipes 12a and 12b, the recovery pipes 13 and the fluid pipes 14a and 14b, and the packers 15a and 15b can be attached to any of the packers 15a and 15b in the freezing pipe 11. It 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 steps of the packers 15a and 15b. Therefore, it is necessary to prevent water-based foreign substances such as frost columns and ice from being generated on the surfaces of the supply pipes 12a and 12b, the recovery pipes 13, the fluid pipes 14a and 14b, or the packers 15a and 15b when the coolant is circulated. Can be done. Further, when the packers 15a and 15b are contracted, the coolant leaks from the closed section X to prevent dew condensation from forming on the inner peripheral surface of the freezing pipe 11, further preventing the generation of aqueous foreign matter in the freezing pipe 11. Can be prevented. Then, 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 not hindered by the aqueous foreign matter, they are surely moved to a predetermined position. be able to.

Further, in the above-described first embodiment, the holding carriage 17 that rolls the inner peripheral surface of the freezing pipe 11 in the pipe axial direction while holding the supply pipe 12b, the recovery pipe 13, and the fluid pipe 14b individually is provided. 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 or moved with respect to the freezing pipe 11, the pipes 12a, 12b, 13, 14a, 14b are twisted. By preventing slack, each pipe and the packers 15a and 15b can be smoothly moved in the pipe axis direction.

Further, in the above-described first embodiment, the elastic members 23 are provided on the packers 15a and 15b, and the elastic members 23 urge the rubbers 19 of the packers 15a and 15b in the contraction direction. Therefore, when the fluid in the packers 15a and 15b is discharged through the fluid tubes 14a and 14b, the contraction of the packers 15a and 15b is promoted by the elastic member 23, and the packers 15a and 15b are contracted quickly and surely. 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 are subsequently moved, it is possible to prevent the smooth movement of the packers 15a and 15b from being hindered in the freezing pipe 11. can do.

Further, 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 is in the pipe axis direction. It is a movable free end. Therefore, when the fluid flows into the rubber 19 of the packers 15a and 15b through the fluid tubes 14a and 14b, the rubber 19 is reasonably expanded in the pipe radial direction of the freezing tube 11 to ensure the inside of the freezing tube 11. Can be blocked. Further, when the fluid inside the rubber 19 is allowed to flow out through the fluid pipes 14a and 14b, the rubber 19 can be reasonably contracted and separated from the freezing pipe 11.

Further, in the freezing tube unit 10 of the first embodiment described above, for example, the number of times the expansion step, the circulation freezing step, the contraction step, and the moving step are repeated in order according to changes in the geology and the surrounding environment and other circumstances. The moving length for moving the supply pipes 12a and 12b, the recovery pipes 13, the fluid pipes 14a and 14b, and the packers 15a and 15b in the freezing pipe 11 is changed, and the positions where the packers 15a and 15b are arranged are changed. Can be done. Therefore, even after the freezing pipe 11 is installed in the ground G, it is possible to freeze only a predetermined portion in the ground G, and the frozen portion and the freezing range in the ground G can be easily changed. It becomes possible to do. Further, even when it is necessary to keep circulating the coolant in the freezing pipe 11 for a long period of time, a part of the freezing pipe 11 in the longitudinal direction can be cooled in a limited manner, so that excess frozen soil growth can be suppressed. Can be done.

In the above-described first embodiment, only the straight freezing tube 11 is installed in the shield tubes 7 and 8, but as in the following second to fourth embodiments, the bent branch freezing tube is used as the shield tube 7 and 8. It may be installed inside.

FIG. 9 is a diagram showing an installed state of the freezing tube unit 10a of the second embodiment. FIG. 9A shows the front end side of the shield tubes 7 and 8, and FIG. 9B shows the rear end side of the shield tubes 7 and 8. In the second embodiment, the freezing pipes 11 are located at the positions of the inner peripheral surfaces of the shield pipes 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, respectively. Books are installed one by one. A plurality of branch freezing tubes 31 are connected to each freezing tube 11 at predetermined intervals in the tube axis direction of each of the shield tubes 7 and 8. In FIG. 9, a part of the branch freezing pipe 31 is shown.

The branch freezing pipe 31 branches from a predetermined position of the freezing pipe 11 and intersects the direction perpendicular to the pipe axis direction of the shield pipes 7 and 8 along the inner peripheral surface of the shield pipes 7 and 8. It extends in a direction parallel to the pipe axis direction. Further, the branch freezing pipe 31 extends on both sides of the freezing pipe 11 in the pipe radial direction. Then, the branch freezing tube 31 is connected to the freezing tube 11 at a position different from the branch position so as to join the freezing tube 11. The freezing pipe 11 and the branched freezing pipe 31 are fixed to the inner peripheral surfaces of the shield pipes 7 and 8.

FIG. 10 is a cross-sectional view of the 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. Supply pipes 12a, 12b, 12c, recovery pipes 13, fluid pipes 14a, 14b, 14c, packers 15a, 15b, 15c, and wire rods 16a, 16b are inserted into the freezing pipe 11. Further, although not shown in FIG. 10, the holding carriage 17 (FIG. 8) described above is also inserted.

As shown in FIGS. 10 and 9, the 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 branched freezing tube 31. Further, 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 connecting portion between the freezing tube 11 and the branched freezing tube 31. Further, a packer 15b is arranged on the rear side of the other section Xb.

The structure of the packer 15a and the connecting structure of the supply pipe 12a, the fluid pipe 14a, and the wire rods 16a and 16b to the packer 15a are the same as those of the first embodiment shown in FIGS. 5 to 7. Further, the structure of the packer 15b and the connecting structure of the supply pipe 12b, the recovery pipe 13, the fluid pipe 14b, and the wire rods 16a and 16b to the packer 15b are the same as those in the first embodiment.

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

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

Further, the 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, similarly 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 hermetically sealed by a sealing member (not shown).

The peripheral surface of the frame 18c is covered with a rubber 19. The holding structure of the rubber 19 is the same as the frames 18a and 18b of the packers 15a and 15b. Inflow / out holes 18p are formed on 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.

By pulling the lead-out portion of the wire rod 16a from the freezing pipe 11 with the traction machine 48 in the same procedure as in the first embodiment described above (see FIG. 7), the supply pipes 12a, 12b, 12c are recovered in the freezing pipe 11. The pipe 13, the fluid pipes 14a, 14b, 14c, the packers 15a, 15b, 15c, and the wires 16a, 16b are inserted and placed in the pipe as shown in FIGS. 9 and 10. Then, after executing the filling step of filling the shield tubes 7 and 8 with the filler and the filling step of filling the freezing tube 11 with the antifreeze, each packer is expanded in the order of packer 15b → 15c → 15a. Perform the expansion step to cause.

Specifically, in the expansion step, the fluid flows into the fluid pipe 14b from the fluid supply source 47. Then, as shown by an arrow in FIG. 10B, the fluid passes from the fluid tube 14b through the fluid passage 18k of the packer 15b and the inflow / outflow hole 18p, and the peripheral surface of the frame 18b and the rubber covering the peripheral surface. It flows in between 19 and 19. Further, 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 between the peripheral surface of the frame 18c and the rubber 19 covering the peripheral surface. Inflow to. 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 inflow / outflow hole 18p, and between the peripheral surface of the frame 18a and the rubber 19 covering the peripheral surface. Inflow to.

Then, the fluid inflates the rubber 19 of each packer 15a, 15b, 15c so as to be separated from the peripheral surfaces of the frames 18a, 18b, 18c, and presses the rubber 19 against the inner peripheral surface of the freezing tube 11, so that the packers 15a, 15b, 15c are released. 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, and 12c communicate with the closed space Xa, and the recovery pipe 13 communicates with the closed space Xb.

In the next circulation freezing step, the coolant cooled by the cooler 42 is supplied to the supply pipe 12b. Then, as shown by the arrow in FIG. 10A, the coolant is the supply path 18i of the packer 15b from the supply pipe 12b, the supply pipe 12c, the supply path 18i of the packer 15c, the supply pipe 12a, and the supply path of the packer 15a. It is supplied to the closed section Xa in the freezing tube 11 through 18i. Further, the coolant flows from the closed section Xa through the branched freezing pipe 31 into the closed section Xb in the freezing pipe 11. Then, the cold heat of the cooling material in the closed sections Xa and Xb and the branched freezing pipe 31 is transmitted to the filler in the sealing pipes 7 and 8 and the surrounding ground via the freezing pipe 11 and the shield pipes 7 and 8. The filler and ground are cooled.

The coolant deprived of cold heat in the closed sections Xa and Xb and the branched freezing pipe 31 is collected in the cooler 42 through the recovery path 18j and the recovery pipe 13 of the packer 15b. Then, after being cooled by the cooler 42, the coolant is supplied to the closed sections Xa and Xb in the freezing pipe 11 and the branched freezing pipe 31 again, and after being deprived of cold heat there, the coolant is sent to the cooler 42. It will be recovered. In this way, by continuing to circulate the cooling material between the cooler 42, the closed sections Xa and Xb in the freezing pipe 11, and the branched freezing pipe 31 for a predetermined time, the closed spaces Xa and Xb and the branched freezing pipe are kept. The filler and ground around 31 are frozen.

In the next shrinkage step, the fluid inside the rubber 19 of the packers 15a, 15b, 15c is externally passed through the inflow / outflow holes 18p of the frames 18a, 18b, 18c, the fluid passage 18k, and the fluid tubes 14a, 14b, 14c. By exhausting to, each packer is contracted in the order of packer 15a → 15c → 15b.

In the next moving step, the rear end of the wire rod 16b led out from the freezing pipe 11 is pulled by the traction machine 48 to pull the supply pipes 12a, 12b, 12c, the recovery pipe 13, the fluid pipes 14a, 14b, 14c, and the packer. The 15a, 15b, and 15c are moved in the freezing tube 11 in the tube axis direction (to the right in FIG. 10) by a predetermined distance. Then, the packer 15a is arranged on the front side of one section Xa in the freezing tube 11 including the branching point between the adjacent branch freezing tube 31 and the freezing tube 11. Further, the packer 15c is arranged on the rear side of one section Xa and on the front side of the other section Xb in the freezing tube 11 including the connecting portion between the branch freezing tube 31 and the freezing tube 11. Further, a packer 15b is arranged on the rear side of the other section Xb.

After that, by repeatedly executing the expansion step, the circulation freezing step, the contraction step, and the moving step in this order as described above, the ground around the freezing pipe 11 and the branch freezing pipe 31 is frozen at predetermined sections. .. Further, in each of the freezing pipes 11 installed in each of the shield pipes 7 and 8, the above-mentioned steps are similarly executed to freeze the ground G around the shield pipes 7 and 8 to form the frozen soil wall 6. Form (FIGS. 1 and 2).

According to the second embodiment described above, the coolant is circulated in the one section Xa and the other section Xb blocked by the packers 15a, 15b, 15c in the freezing tube 11 and the branched freezing tube 31 communicating with these sections. The freezing range of the ground that is cooled and frozen with a coolant can be expanded. Further, since both ends of the branched 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 one freezing pipe 11 can be expanded. Therefore, the ground around the shield pipes 7 and 8 can be frozen evenly and more efficiently at predetermined sections. Further, the number of freezing tubes 11 installed in the shield tubes 7 and 8 having a large diameter can be reduced, the number of executions of each process can be reduced, and the construction load can be reduced.

FIG. 11 is a diagram showing an installed state of the freezing tube unit 10b of the third embodiment. FIG. 11A shows the front end side of the shield tubes 7 and 8, and FIG. 11B shows the rear end side of the shield tubes 7 and 8. 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 of the freezing tubes 11, but the branched freezing tubes are connected. The shape of 32 is different from that of the branch freezing tube 31 (FIG. 9) of the second embodiment. In FIG. 11, a part of the branch freezing pipe 32 is shown.

The branch freezing pipe 32 branches from a predetermined position of the freezing pipe 11 and intersects the direction perpendicular to the pipe axis direction of the shield pipes 7 and 8 along the inner peripheral surface of the shield pipes 7 and 8. It extends in a direction parallel to the pipe axis direction. The branch freezing tube 32 is connected to the freezing tube 11 at a position different from the branch position so as to merge with the freezing tube 11. The freezing pipe 11 and the branch freezing pipe 32 are fixed to the inner peripheral surfaces of the shield pipes 7 and 8. The above points are the same as those of the branch freezing tube 31 of the second embodiment, but the branch freezing tube 32 of the third embodiment extends only to one side of the freezing tube 11 in the pipe radial direction. Further, the distance between the branching portion and the connecting portion (merging portion) of the branched freezing tube 32 in the freezing tube 11 is shorter than the length of the portion parallel to the tube axis of the freezing tube 11 in the branched freezing tube 32.

In the freezing tube 11, the packer 15a is arranged on the front side of one section Xa including the branching point between the freezing tube 11 and the branched freezing tube 32. Further, a packer 15c is arranged between the branching portion and the connecting portion (merging portion) of the freezing pipe 11 and the branch freezing pipe 32. Further, a packer 15b is arranged on the rear side of the other section Xb in the freezing tube 11. The distance between the packer 15c and the packer 15b is about the same as the length of the portion of the branched freezing tube 32 parallel to the tube axis of the freezing tube 11.

The supply pipes 12a, 12b, 12c, the recovery pipe 13, the fluid pipes 14a, 14b, 14c, the wire rods 16a, 16b, etc. are inserted into the freezing pipe 11 as in the second embodiment shown in FIG. (Not shown). The connection state between these and the packers 15a, 15b, and 15c is also the same as in the second embodiment.

Also in such a third embodiment, the coolant is used by circulating the coolant in the one section Xa, the other section Xb, and the branched freezing tube 32 blocked by the packers 15a, 15b, and 15c in the freezing tube 11. The range of ground to be cooled and frozen can be expanded. Further, since both ends of the branched 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 one freezing pipe 11 can be expanded. Therefore, the ground around the shield pipes 7 and 8 can be frozen evenly and more efficiently at predetermined sections. Further, the number of freezing pipes 11 installed in the shield pipes 7 and 8 can be reduced, the number of executions of each process can be reduced, and the construction load can be reduced.

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

Each of the branched freezing tubes 33a and 33b branches from a predetermined position of each of the freezing tubes 11a and 11b and is perpendicular to the tube axial direction of the shielded tubes 7 and 8 so as to be along the inner peripheral surface of the shielded tubes 7 and 8. It extends in the direction intersecting with and in the direction parallel to the pipe axis direction. The branch freezing pipes 33a and the branch freezing pipes 33b facing each other in the 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. The branch freezing pipes 33a and 33b and the relay pipe 34 communicate with each other. That is, the branched 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 branched freezing tubes 33a and 33b are fixed to the inner peripheral surfaces of the shield tubes 7 and 8. The outer peripheral surface of the relay pipe 34 is covered with the 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 branched freezing tube 33a, and FIG. 13 (b) shows the vicinity of the branching point between the freezing tube 11b and the branched freezing tube 33b.

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

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

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

As shown in FIGS. 13B and 12, a packer 15d is arranged on the front side of the other section Xd in the freezing tube 11b including the branching point between the freezing tube 11b and the branch freezing tube 33b. Further, 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 in the freezing tube 11b is similar to the structure of the packer 15 in the freezing tube 11a. The tip of the fluid pipe 14a is connected to the rear end of the packer 15d in the freezing pipe 11b.

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

Although not shown, the wire rods 16a and 16b shown in FIG. 7 and the like are inserted into the freezing tubes 11a and 11b. Further, the packers 15c, 15d, and 15e are formed with insertion holes through which the wire rods 16a and 16b are inserted, similar to the insertion holes 18g and 18h shown in FIG. 7 and the like. The connected state and the penetrating state of the wire rods 16a and 16b and the packer 15d are the same as those of the above-mentioned packer 15a. The connected state and the penetrating state of the wire rods 16a and 16b and the packers 15c and 15e are the same as those of the above-mentioned packer 15b.

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 the rubber 19 is the same as that of the packers 15a, 15b, 15c of the first to third embodiments. Further, as in the first to third embodiments, elastic members 23 are provided between the rubber 19 and the frames 18c, 18d, 18e, and the peripheral surfaces of the frames 18c, 18d, 18e are formed on the peripheral surfaces of the frames 18c, 18d, 18e. The inflow / outflow hole 18p is formed.

By pulling the lead-out portion of the wire rod 16a from the freezing pipe 11a with the traction machine 48 in the same procedure as in the first embodiment described above (see FIG. 7), the supply pipes 12b and the fluid pipes 14a and 14b are inserted into the freezing pipe 11a. , Packers 15c, 15d, and wire rods 16a, 16b (not shown) are inserted and placed in the pipe as shown in FIG. 13 (a). Further, by pulling the lead-out portion of the wire rod 16a from the freezing pipe 11b, the recovery pipe 13, the fluid pipes 14a and 14b, the packers 15d and 15e, and the wire rods 16a and 16b (not shown) are inserted into the freezing pipe 11b. These are arranged in the pipe as shown in FIG. 13 (b). Then, after executing the filling step of filling the shield tubes 7 and 8 with the filler and the filling step of filling the freezing tubes 11a and 11b with the antifreeze material, expansion to expand the packers 15c, 15d and 15e. Perform the process. Since this expansion step is basically the same as in the case of the first embodiment and the second embodiment, detailed description thereof will be omitted.

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

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

The coolant deprived of cold heat in the closed sections Xc and Xd and the branched freezing pipes 33a and 33b is collected in the cooler 42 through the recovery path 18j and the recovery pipe 13 of the packer 15e. Then, after being cooled by the cooler 42, the cooling material is supplied again into the closed sections Xc and Xd in the freezing pipes 11a and 11b and in the branched freezing pipes 33a and 33b, and after being deprived of cold heat, the cooling material is then deprived. It is collected in the cooler 42. In this way, by continuing to circulate the cooling material between the cooler 42, the closed sections Xc and Xd in the freezing pipes 11a and 11b, and the branched freezing pipes 33a and 33b for a predetermined time, the closed space The filler and ground around Xc, Xd and the branched freezing tubes 33a, 33b are frozen.

In the next contraction step, the fluid inside the rubber 19 of each packer is exhausted to the outside through the inflow / outflow hole 18p, the fluid passage 18k, and the fluid pipe 14b, thereby contracting the packers 15c, 15d, and 15e. ..

In the next moving step, the supply pipe 12b, the recovery pipe 13, and the fluid pipe 14b are pulled by the traction machine 48 at the rear end of the wire rod 16b (not shown) derived from the freezing pipes 11a and 11b in the same manner as described above. , And the packers 15c, 15d, 15e are moved in the freezing tubes 11a, 11b in the tube axis direction (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 between 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. Further, the packer 15d is arranged on the front side of the other section Xd in the freezing pipe 11b including the branching point between the adjacent branch freezing pipe 33b and the freezing pipe 11b, and the packer 15e is arranged on the rear side of the other section Xd. do.

After that, by repeatedly executing the expansion step, the circulation freezing step, the contraction step, and the moving step in this order as described above, the ground around the freezing tubes 11a and 11b and the branched freezing tubes 33a and 33b is formed for each predetermined section. Let's freeze it. Further, in the freezing pipes 11a and 11b installed in the shield pipes 7 and 8, the above-mentioned steps are similarly executed to freeze the ground G around the shield pipes 7 and 8 and freeze the soil wall. 6 is formed (FIGS. 1 and 2).

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

Therefore, the coolant is circulated in the one section Xc, the other section Xd, and the branched freezing pipes 33a, 33b blocked by the packers 15c, 15d, 15e in the freezing pipes 11a, 11b, and the ground is frozen by the coolant. The freezing range can be expanded. Further, since the number of tubes to be inserted into the freezing tubes 11a and 11b can be reduced, the tubes and packers can be easily inserted and moved into the freezing tubes 11a and 11b.

In the above-described embodiment, an example in which the freezing pipes 11, 11a and 11b are installed in the shield pipes 7 and 8 buried in the ground has been shown, but as in the following embodiment, the freezing pipes are directly installed in the ground. May be installed.

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

In order to construct the underground structure 71, first, as shown in FIG. 14A, a plurality of shafts 72 and 73 are constructed in the ground G at a predetermined depth. Next, using a freezing pipe 11c that also functions as a horizontal boring pipe, for example, while excavating the ground G in the horizontal direction from one shaft 72 to the other shaft 73, the freezing pipe 11c is placed in the ground G. Install. At this time, as shown in FIG. 15A, a plurality of freezing pipes 11c are installed in an annular shape on the ground G between the plurality of shafts 72 and 73 at predetermined intervals.

Then, a freezing method is performed in which the ground G around each freezing pipe 11c is frozen. This freezing method uses, for example, the freezing tube unit 10 of the first embodiment shown in FIGS. 5 to 8 (the freezing tube 11 replaces the freezing tube 11c) and the equipment shown in FIG. Do it with. As a result, an annular frozen soil wall 76 having high strength and water blocking performance is formed at predetermined sections in the ground G between the shafts 72 and 73.

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 permafrost wall 76 does not collapse and groundwater does not infiltrate inside the permafrost wall 76, excavation and assembly 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 the freezing tube unit 10d according to the fifth embodiment. 16 (a) and 16 (b) have cross sections that differ 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 pre-closed. A supply pipe 12b, a fluid pipe 14b, a wire rod 16b, and a packer 15a are inserted in the freezing pipe 11d. The rear end portion (upper end portion in FIG. 16) of the freezing pipe 11d is exposed above the ground and is closed by the closing member 29.

A plurality of through holes 29h, 29i, 29j, and 29k are formed in the closing member 29. As shown in FIG. 16A, the tip end portion of the recovery pipe 13 is connected to the closing member 29 so as to communicate with the through hole 29h. That is, the recovery pipe 13 communicates with the inside of the freezing pipe 11d near the rear end of the freezing pipe 11d. The rear end of the recovery pipe 13 is connected to the relay branch pipe 61 (FIG. 3). In the example of FIG. 16, the recovery tube 13 is not inserted into the freezing tube 11d, but as another example, the recovery tube 13 is penetrated through the through hole 29h, and the tip of the recovery tube 13 is inserted into the freezing tube 11d. You may insert it.

As shown in FIGS. 16A and 16B, a supply pipe 12b, a fluid pipe 14b, and a wire rod 16b are inserted into 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 hermetically sealed by a sealing member (not shown).

A supply path 18i (FIG. 16 (a)), a fluid path 18k (FIG. 16 (b)), and an insertion hole 18h (FIG. 16 (b)) are formed in the frame 18a of the packer 15a. As shown in FIG. 16A, the tip end portion of the supply pipe 12b is connected to the rear end portion of the frame 18a so as to communicate with the supply path 18i. One end of the supply path 18i is opened as desired in 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. 16B, the tip end portion of the fluid pipe 14b is connected to the rear end portion of the frame 18a so as to communicate with the fluid passage 18k. The fluid passage 18k is blocked on the distal end side of the frame 18a. The rear end of the fluid tube 14b is connected to a fluid supply source 47 (FIG. 3) outside the freezing tube 11d.

Further, as shown in FIG. 16B, the tip end portion of the wire rod 16b is inserted into the insertion hole 18h of the frame 18a. The tip of the wire rod 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 towing machine 48 (FIG. 3) outside the freezing pipe 11d.

A rubber 19 is held by holding members 20a, 20b, 21a, and 21b on the peripheral surface of the frame 18a. Further, an inflow / outflow hole 18p communicating with the fluid passage 18k is formed on the peripheral surface of the frame 18a. The inflow / outflow hole 18p is covered with a rubber 19. Elasticity for pulling the rubber 19 toward the peripheral surface side of the frame 18a and contracting the packer 15a by sliding the slider 20b toward the flange portion 18y side of the frame 18a between the rubber 19 and the frame 18a. A member 23 is provided.

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

In the freezing method using the freezing pipe unit 10d, first, as shown in FIGS. 16 and 17, the freezing 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 (interpolation step). At this time, for example, as shown in FIG. 17, each member is once inserted so that the packer 15a is located 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. 16 (b), the packer 15a is located near the lowest position of the predetermined range in the ground G to be frozen. Each member is moved in the direction of the tube axis of the freezing tube 11d (movement 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. Further, the recovery pipe 13 is connected to the rear end of the freezing pipe 11d.

Next, the fluid supplied from the fluid supply source 47 (FIG. 3) is allowed to flow into the inside of the packer 15a (fluid path 18k, 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 close the inside of the freezing tube 11d (expansion step). As a result, as shown in FIG. 16A, the closed space Xs is formed above the packer 15a in the freezing tube 11d. Next, the coolant cooled by the cooler 42 (FIG. 3) is closed from the vicinity of the packer 15a in the freezing pipe 11d through the pipe 57 of FIG. 3, the relay branch pipe 60, and the supply pipe 12b of FIG. 16A. Supply to section Xs. Then, the coolant is circulated so as to collect the coolant in the closed space Xs from the vicinity of the rear end of the freezing pipe 11d to the cooler 42 through the recovery pipe 13 and the relay branch pipe 61 and the pipe 59 of FIG. The ground G around the closed space Xs is frozen (circulation freezing step). In FIG. 16A, the frozen portion in the ground G is shown by cross-hatching.

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

FIG. 18 is a cross-sectional view of the freezing tube unit 10e according to the sixth embodiment. 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. A supply pipe 12a, 12b, a recovery pipe 13, a fluid pipe 14b, a wire rod 16b, and a packer 15b are inserted in the freezing pipe 11d. The rear end of the freezing pipe 11d is exposed above the ground and is closed by the closing member 29. A recovery pipe 13, a supply pipe 12b, a fluid pipe 14b, and a wire rod 16b are inserted into the through holes 29h, 29i, 29j, and 29k formed in the closing member 29, respectively.

The frame 18b of the packer 15b includes a supply path 18i (FIG. 18 (a)), a recovery path 18j (FIG. 18 (a)), a fluid path 18k (FIG. 18 (b)), and an insertion hole 18h (FIG. 18 (b)). )) Is formed. As shown in FIG. 18A, the rear end portion of the supply pipe 12a is connected to the tip end portion (lower end portion in FIG. 18) of the frame 18b so as to communicate with the supply path 18i. The supply pipe 12a has a predetermined length and has an open tip. The tip of the supply pipe 12b is connected to the rear end of the frame 18b (the upper end in FIG. 18) so as to communicate with the supply passage 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. 18A, the tip 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. The recovery path 18j is opened on the tip end side 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. 18B, the tip 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 fluid passage 18k is blocked on the distal end side of the frame 18b. The rear end of the fluid tube 14b is connected to a fluid supply source 47 (FIG. 3) outside the freezing tube 11d.

Further, as shown in FIG. 18B, the tip end portion of the wire rod 16b is inserted into 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 towing machine 48 (FIG. 3) outside the freezing pipe 11d.

A rubber 19 is held by holding members 20a, 20b, 21a, and 21b on the peripheral surface of the frame 18b. Further, an inflow / outflow hole 18p communicating with the fluid passage 18k is formed on the peripheral surface of the frame 18b. The inflow / outflow hole 18p is covered with a rubber 19. An elastic member 23 is provided between the rubber 19 and the frame 18b for pulling the rubber 19 toward the peripheral surface side of the frame 18b via the slider 20b and contracting the packer 15b.

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

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

Next, the fluid supplied from the fluid supply source 47 (FIG. 3) is allowed to flow into the inside of the packer 15b (the fluid path 18k, the inflow / outflow 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 close the inside of the freezing tube 11d (expansion step). As a result, as shown in FIG. 18A, the closed space 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 of FIG. 3, the relay branch pipe 60, and the supply pipes 12a and 12b of FIG. 18A from the vicinity of the tip of the freezing pipe 11d. It is supplied to the closed section Xt. Then, the coolant in the closed space 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. The ground G around the closed space Xt is frozen (circulation freezing step). In FIG. 18A, the frozen portion in the ground G is shown by cross-hatching.

After freezing the ground G around the closed space Xt, the circulation of the coolant is stopped, and then the fluid in the packer 15b is allowed to flow out through the fluid pipe 14b to contract the packer 15b (contraction step). Then, by removing the closing member 29 from the rear end of the freezing pipe 11d and pulling the wire rod 16b, the supply pipes 12a and 12b, the recovery pipe 13, the fluid pipe 14b, the wire rod 16b, and the packer 15b are removed from the inside of the freezing pipe 11d. Extract and collect these.

According to the fifth and sixth embodiments described above, the fluid is allowed to flow into the packers 15a and 15b inserted at predetermined positions in the freezing pipe 11d through the fluid pipe 14b, and the packers 15a and 15b are expanded to freeze. One side of the pipe 11d in the pipe axial direction is closed by the packers 15a and 15b. Further, since the other side of the freezing tube 11d in the tube axis 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 supplied from one end side of the closed spaces Xs and Xt through the supply pipes 12a and 12b, and the coolant is circulated so as to recover the coolant through the recovery pipe 13 from the other end side of the closed spaces Xs and Xt. I'm letting you. Therefore, the coolant can be spread all over the closed spaces Xs and Xt, and the ground G in a predetermined range around the closed spaces Xs and Xt can be frozen evenly and efficiently.

Further, even after the freezing pipe 11d is installed in the ground G, the packers 15a and 15b in the freezing pipe 11d can be pulled by pulling the wire rod 16b or the like according to changes in the geology or the surrounding environment or other circumstances. The size and position of the closed sections Xs and Xt can be easily changed by changing the arrangement position of. 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 freezing range in the ground G.

In the present invention, various embodiments other than those described above can be adopted.

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

Further, in the first to fourth embodiments described above, after the step of installing the freezing tube in the shielded tube and the step of inserting the supply tube, the recovery tube, the fluid tube, the packer, etc. into the frozen tube, the inside of the shielded tube is inserted. Although the example of executing the filling step of the filler of is shown, the filling step may be carried out after the installation step and before the interpolation step.

Further, in the above embodiment, an example is shown in which the packer is moved in the pipe axis direction in the freezing pipe by pulling the wire rod connected to the packer, but the present invention is not limited to this. For example, the packer may be moved by omitting the wire and pulling the supply pipe, recovery pipe, or fluid pipe.

Further, in the first embodiment, the wire rod 16a connected to the packer arranged on the most tip side of the freezing tube is turned around through a pulley 27 (FIG. 7) provided at the tip of the freezing tube, and then after the freezing tube. An example is shown in which a supply pipe, a recovery pipe, a fluid pipe, and a packer are inserted into a freezing pipe by deriving from the end and pulling the rear end of the wire rod 16a, but the present invention is not limited to this. No. For example, a wire rod connected to a packer arranged on the most tip side of the freezing pipe without providing a pulley 27 is inserted from the rear end portion of the freezing pipe, passed through the freezing pipe, and led out from the tip portion of the freezing pipe. The supply tube, recovery tube, fluid tube, and packer may be inserted or moved into the freezing tube by pulling the lead-out portion of the.

Further, in the above embodiment, an example in which the rubber is easily contracted by the elastic force of the elastic member provided inside the rubber of the packer is shown, but the present invention is not limited to this. For example, the packer may be forcibly contracted 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 embodiment, an example in which the supply pipe, the recovery pipe, or the fluid pipe is fixed to the packer has been shown, but the present invention is not limited to this. For example, a mechanism for slidably holding an inner pipe such as a supply pipe, a recovery pipe, or a fluid pipe in the direction of the freezing pipe axis is provided in the packer frame so that the protrusion length of the inner pipe from the packer can be changed. You may.

Further, in the above embodiment, the coolant is supplied from the front end side of the freezing pipe to the closed space formed in the freezing pipe, and the coolant is collected from the rear end side of the freezing pipe. Although an example in which the recovery tube is arranged is shown, the present invention is not limited to this. On the contrary, the supply pipe and the recovery pipe are arranged so that the coolant is supplied from the rear end side of the freezing pipe and the coolant is recovered from the tip side of the freezing pipe to the closed space formed in the freezing pipe. You may.

Further, in the above embodiment, the ground freezing method and the freezing pipe unit of the present invention are applied in order to form a frozen soil wall in the surrounding ground when constructing a ground structure having a large cross section at a large depth. Although examples have been given, the ground freezing method and the freezing tube unit of the present invention can also be applied when forming a frozen soil wall for other purposes.

7, 8 shielded pipe (large diameter pipe)
10, 10a, 10b, 10c, 10d, 10e Freezing pipe unit 11, 11a, 11b, 11c, 11d Freezing pipe 12a, 12b, 12c Supply pipe 13 Recovery pipe 14a, 14b, 14c Fluid pipe 15a, 15b, 15c, 15d, 15e packer 16a, 16b wire rod 17 holding trolley 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 (holding member)
23 Elastic member 27 Pulley 31, 32, 33a, 33b Branch freezing pipe 40 Refrigerator 47 Fluid supply source G Ground X, Xs, Xt Blocking section Xa, Xc One section (blocking section)
Xb, Xd Other section (closed section)

Claims (16)

The installation process of installing a freezing pipe in the ground and
An interpolation step of inserting a supply pipe, a recovery pipe, a fluid pipe, and a plurality of packers into the freezing pipe and arranging the packers at predetermined positions in the pipe axial direction of the freezing pipe.
An expansion step of allowing a fluid to flow into the packer through the fluid pipe and expanding the plurality of packers so as to close the freezing pipe.
The coolant is supplied to the closed section in the freezing pipe formed by the expansion of the plurality of packers through the supply pipe, and the coolant is recovered from the closed section through the recovery pipe. A circulation freezing step that circulates and freezes the ground around the blockage section,
A contraction step of causing the fluid in the packer to flow out through the fluid pipe and contracting the plurality of packers.
A ground freezing method comprising a moving step of moving the supply pipe, the recovery pipe, the fluid pipe, and the contracted plurality of packers in the pipe axial direction in the freezing pipe. In the ground freezing method according to claim 1,
After executing the installation step, the insertion step, the expansion step, the circulation freezing step, the shrinking step, and the moving step in this order, the expanding step, the circulating freezing step, the shrinking step, and the moving step are performed. A ground freezing method characterized by being repeatedly executed in order. In the ground freezing method according to claim 1 or 2.
In the insertion step, a wire rod connected to the plurality of packers is inserted into the freezing tube, and at least one end of the wire rod is led out from the freezing tube.
By pulling the derived end of the wire rod in the insertion step or the moving step, the supply pipe, the recovery pipe, the fluid pipe, and the plurality of packers are placed 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 method, characterized in that a filling step of filling the freezing pipe with an antifreeze material is executed 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 freezing pipes are installed in the large-diameter pipe embedded in the ground in parallel with the pipe axis direction of the large-diameter pipe.
After that, at least before the circulation freezing step, the ground freezing method is characterized in that the filling step of filling the large-diameter pipe with the filler is executed. In the ground freezing method according to claim 5,
In the installation step, the branched freezing tube that branches from the freezing tube, extends in a direction intersecting or parallel to the tube axis direction of the large-diameter tube, and is connected to the freezing tube, has the large diameter. Install multiple pipes at predetermined intervals
The packers are arranged on both sides of one section in the freezing tube including the branching point between the freezing tube and the branched freezing tube, and the other section in the freezing tube including the connecting point between the freezing tube and the branched 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.
Then, in the circulation freezing step, the ground freezing method is characterized in that the coolant is circulated in the one section, the other section, and the branched freezing pipe in the freezing pipe. Freezing pipes installed in the ground and
A supply pipe that supplies the coolant into the freezing pipe and
A recovery pipe for collecting the coolant in the freezing pipe and
With a packer that closes the freezing tube,
A fluid tube for allowing a fluid to flow into the packer is provided.
In a state where the freezing pipe is closed by the packer, the cooling material is circulated by supplying the cooling material into the freezing pipe through the supply pipe and collecting the cooling material from the freezing pipe through the recovery pipe. In the freezing tube unit that freezes the ground around the freezing tube.
The packer is composed of a plurality of packers, and 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 pipe axial direction of the freezing pipe.
The supply pipe communicates with the closed section in the vicinity of one packer in the closed section in the frozen pipe closed by the plurality of packers.
The recovery pipe communicates with the blockage section in the vicinity of the other packer in the blockage section.
A freezing pipe unit characterized in that, in a state where the packer is contracted, the supply pipe, the recovery pipe, the fluid pipe, and the packer can move in the pipe axial direction in the freezing pipe. In the freezing tube unit according to claim 7,
Further provided with a holding trolley to be inserted into the freezing tube,
The holding carriage has a plurality of holding portions for individually holding the supply pipe, the recovery pipe, or the fluid pipe, and wheels that roll the inner peripheral surface of the freezing pipe in the pipe axial direction. A freezing tube unit characterized by being. In the freezing tube unit according to claim 7 or 8.
A freezing tube unit which is connected to the packer, inserted into the freezing tube in the axial direction of the tube, and further provided with a wire rod having at least one end led out from the freezing tube. In the freezing tube unit according to claim 9,
A pulley installed on the tip side of the freezing pipe and on which the wire rod is hung is further provided.
One end of the wire rod whose direction is changed by the pulley is connected to the packer arranged at the most end side of the freezing pipe, and the other end is led out from the rear end side of the freezing pipe. A freezing tube unit characterized by that. In the freezing tube unit according to any one of claims 7 to 10.
A freezing tube unit provided in the packer and further provided with an elastic member that urges the packer in the contraction direction. In the freezing tube unit according to any one of claims 7 to 11.
The packer
With the frame to which the supply pipe, the recovery pipe, or the fluid pipe is connected,
A tubular rubber covering the peripheral surface of the frame and
It has a plurality of holding members that hold both ends of the rubber on the peripheral surface of the frame, respectively.
A freezing tube unit characterized in that 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 freezing pipe is installed in a large-diameter pipe buried in the ground in parallel with the pipe axis direction of the large-diameter pipe.
A plurality of branched freezing pipes are installed in the large-diameter pipe at predetermined intervals, branch from the freezing pipe, extend in a direction intersecting or parallel to the pipe axis direction, and are connected to the freezing pipe. Further prepare
The packers are arranged on both sides of a section in the freezing tube including a branching point between the freezing tube and the branched freezing tube, and in the freezing tube including a connecting point between the freezing tube and the branched freezing tube. It is arranged on both sides of the other section, and by expanding each, the one section and the other section are closed.
The supply pipe communicates with the one section and
The recovery pipe communicates with the other section,
A freezing pipe unit characterized in that the coolant is circulated in the one section, the other section, and the branched freezing pipe through the supply pipe and the recovery pipe. In the freezing tube unit according to claim 13,
A plurality of the freezing tubes are installed in the large diameter tube, and the freezing tubes are installed.
The branched freezing tube is branched from one of the freezing tubes and connected to the other freezing tube.
The supply pipe, the fluid pipe, and the plurality of packers are inserted into the one freezing pipe.
A freezing tube unit, wherein the recovery tube, the fluid tube, and the plurality of packers are inserted into the other freezing tube. The installation process of installing a freezing pipe in the ground and
An insertion step of inserting a supply pipe, a fluid pipe, and a packer into the freezing pipe and arranging the packer at a predetermined position in the tube axial direction of the freezing pipe.
An expansion step of allowing a fluid to flow into the packer through the fluid tube and expanding the packer so as to block one side of the freezing tube in the axial direction of the tube, which is not previously closed.
The coolant is supplied to the closed section in the freezing pipe formed by the expansion of the packer through the supply pipe, and the coolant is recovered from the closed section to circulate the coolant and cause the closed section. Circulation freezing process that freezes the ground around the
A contraction step of causing the fluid in the packer to flow out through the fluid tube and contracting the packer.
A ground freezing method comprising a moving step of moving the supply pipe, the fluid pipe, and the contracted packer in the pipe axis direction in the freezing pipe. Freezing pipes installed in the ground and
A supply pipe that supplies the coolant into the freezing pipe and
A recovery pipe for collecting the coolant in the freezing pipe and
With a packer that closes the freezing tube,
A fluid tube for allowing a fluid to flow into the packer is provided.
In a state where the freezing pipe is closed by the packer, the cooling material is circulated by supplying the cooling material into the freezing pipe through the supply pipe and collecting the cooling material from the freezing pipe through the recovery pipe. In the freezing tube unit that freezes the ground around the freezing tube.
The supply pipe and the fluid pipe are inserted into the freezing pipe in a state of being connected to the packer.
When the fluid flows in and expands through the fluid pipe, the packer closes one side of the freezing pipe in the axial direction that is not previously closed to form a closed space in the freezing pipe, and at the same time, the packer forms a closed space. When the fluid flows out through the fluid pipe, it contracts and
In the closed section, the supply pipe communicates with the closed section in the vicinity of one end in the pipe axial direction, and the recovery pipe communicates with the closed section in the vicinity of the other end in the pipe axial direction. ,
A freezing pipe unit characterized in that, in a state where the packer is contracted, the supply pipe, the fluid pipe, and the packer can move in the pipe axial direction in the freezing pipe.

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