JP7361668B2 - Segments for frozen construction method and frozen construction method - Google Patents

Description

The present invention relates to a segment for a frozen construction method and a frozen construction method.

Patent Document 1 describes a method for freezing the surrounding ground of a shield tunnel inside a shield tunnel lining constructed by assembling a plurality of segments along the circumferential and axial directions of an excavated tunnel. A tube arrangement is disclosed.

Japanese Patent Application Publication No. 2016-160717

In the invention described in Patent Document 1, a freezing tube is arranged on the inner circumferential surface of a concrete segment. Concrete segments generally have low heat conductivity, so it takes a relatively long time after the refrigerant flows through the frozen pipe until the temperature of the ground around the shield tunnel drops and frozen soil is created. becomes. For this reason, the start of the next process, which is to be carried out after sufficiently strong frozen soil has been created, is delayed, the construction period becomes longer, and there is a risk that construction costs will increase as a result.

An object of the present invention is to provide a segment that can efficiently create frozen soil around a shield tunnel.

The present invention relates to a segment for a frozen construction method that is assembled along the circumferential and axial directions of a tunnel constructed underground and serves as a lining, which is formed to include at least concrete, and has an outer circumferential surface facing a tunnel and a frozen construction segment. A main body having an inner circumferential surface to which a pipe is attached, and a heat conductive part provided in the main body and having a higher thermal conductivity than the main body, the heat conductive part having at least a freezing pipe on the inner circumferential side. , and extends from the position toward the outer circumferential surface.

According to the present invention, it is possible to provide a segment that can efficiently create frozen soil around a shield tunnel.

FIG. 3 is a plan view of a branching and merging section where a main line and a ramp branch and merge. 2 is a sectional view taken along line AA in FIG. 1. FIG. FIG. 2 is a schematic diagram showing a construction method of an underground structure in chronological order. FIG. 4 is a schematic diagram showing a construction method for an underground structure following FIG. 3 in chronological order. FIG. 2 is a diagram for explaining a configuration for creating frozen soil. 6 is a view seen in the direction indicated by arrow B in FIG. 5. FIG. 7 is a sectional view taken along line CC in FIG. 6. FIG. 8 is a view seen toward the direction indicated by arrow D in FIG. 7. FIG. 8 is a diagram showing a first modification, and is a sectional view showing a cross section corresponding to FIG. 7. FIG. 9 is a diagram illustrating a second modification, and is a diagram seen in the same direction as FIG. 8. FIG.

Hereinafter, with reference to the drawings, a freezing construction method segment 100 according to an embodiment of the present invention and a freezing construction method using the freezing construction method segment 100 will be described.

The frozen construction method segment 100 according to the embodiment of the present invention is provided along the wall of a pit such as a tunnel (excavation shaft) or a shaft constructed underground, thereby becoming a lining for the pit. For example, it is used as a segment piece that becomes the tunnel lining by fitting along the wall of an excavated tunnel (excavation shaft) at the rear of a shield excavator that excavates underground (grounds). be.

In the following, a case will be described in which the frozen construction segment 100 is used to construct a preceding outer shell 21A of a preceding shield tunnel 21 to be described later, which is formed in the process of constructing a large cross-section tunnel 10 underground. Note that the segment 100 for the freezing construction method according to the embodiment of the present invention is not limited to that used for constructing the preceding shell 21A.

As shown in FIGS. 1 and 2, the large-section tunnel 10 is an underground structure constructed to surround the branching and merging area of the main line shield tunnel 11 and the lamp shield tunnel 12, and serves as the outer shell of the underground cavity 14. It has a substantially arc-shaped outer frame 15. FIG. 1 is a plan view of a junction where a main line and a ramp diverge and merge, and FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. The main line shield tunnel 11 and the lamp shield tunnel 12 are shield tunnels each having a circular cross section and which are excavated underground in advance by a shield construction method.

The outer frame 15 is composed of a plurality of shield tunnels 20 built on top of each other so as to surround the main line shield tunnel 11 and the lamp shield tunnel 12, and a steel plate concrete structure 30 built within the plurality of shield tunnels 20. This is the main body of the building.

Next, with reference to FIGS. 3 and 4, a method for constructing the large cross-section tunnel 10 provided with the outer shell 15 will be briefly described. FIGS. 3A to 3C and FIGS. 4A to 4C are schematic diagrams showing a method for constructing the large cross-section tunnel 10 in chronological order.

First, with reference to FIG. 3(A), a process of forming the preceding shield tunnel 21, which is constructed in advance among the shield tunnels 20, will be described. In this process, a plurality of advance shield excavators (not shown) are launched from a starting base (not shown) constructed in advance at one end of the large-section tunnel 10 toward the other end of the large-section tunnel 10, thereby causing a plurality of A preceding shield tunnel 21 is constructed.

The plurality of preceding shield tunneling machines start at predetermined intervals in the circumferential direction so as to surround the main line shield tunnel 11 and the lamp shield tunnel 12. The inner circumferential surface of the preceding excavation shaft (tunnel, pit) 21B formed in the ground (ground) by the excavation of the preceding shield excavator is a predetermined width (e.g. 1 m) of segment rings are formed one after another. By connecting the plurality of segment rings in the tunnel axial direction, a leading outer shell 21A, which is a part of the outer shell 20A of the shield tunnel 20 and a part of the leading shield tunnel 21, is formed.

As a result, a plurality of preceding shield tunnels 21 are constructed at predetermined intervals in the circumferential direction so as to surround the main line shield tunnel 11 and the lamp shield tunnel 12.

Furthermore, in this step, frozen soil (frozen soil) 24 is created in preparation for the subsequent formation of the trailing shield tunnel 22. The frozen soil 24 is created by flowing a refrigerant through a freezing pipe (not shown) attached to the inner peripheral surface of the leading outer shell 21A. In this step, the frozen soil 24 is created not around the entire circumference of the leading outer shell 21A, but around the portion of the leading outer shell 21A that will be cut by the trailing shield excavator (not shown) that constructs the trailing shield tunnel 22. A refrigerant is flowed through a predetermined range of freezing tubes. Preferably, the predetermined range includes the boundary between the leading outer shell 21A and the trailing outer shell 22A. Note that the configuration of the preceding shield tunnel 21 when creating the frozen ground 24 will be described later.

Next, the process of forming the trailing shield tunnel 22 will be described with reference to FIG. 3(B). In this process, a trailing shield tunnel 22 is constructed between two adjacent leading shield tunnels 21 by starting a trailing shield tunnel machine (not shown) from a starting base along the leading shield tunnel 21 .

The trailing shield tunnel excavator excavates tunnels that are adjacent to each other at a predetermined interval, and in this embodiment excavates while cutting a part of the leading outer shell 21A of the two leading shield tunnels 21. The inner peripheral surface of the trailing excavation shaft (tunnel) 22B formed underground (ground mass) by the trailing shield excavation machine is coated with the outside of the shield tunnel 20 in the same manner as in the process of forming the leading shield tunnel 21. A trailing outer shell 22A, which is part of the shell 20A and part or all of the trailing shield tunnel 22, is formed.

As a result, the trailing shield tunnel 22 is constructed so as to partially overlap the adjacent leading shield tunnel 21 over the entire axial direction of the tunnel. The leading outer shell 21A of the leading shield tunnel 21 and the trailing outer shell 22A of the trailing shield tunnel 22 are arranged alternately in the circumferential direction to form an annular outer shell 20A surrounding the main shield tunnel 11 and the lamp shield tunnel 12. is formed.

As mentioned above, since frozen soil 24 is created around the preceding shield tunnel 21, even if a part of the preceding outer shell 21A of the preceding shield tunnel 21 is cut by the trailing shield excavator, the preceding shield Groundwater is prevented from flowing into the tunnel 21.

Next, the process of creating frozen soil 25 around the shield tunnel 20 will be described with reference to FIG. 3(C). In this step, frozen soil (frozen soil) 25 is created in preparation for the subsequent formation of the steel plate concrete structure 30 inside the outer shell 20A. The frozen soil 25 is created by flowing a refrigerant through freezing pipes (not shown) attached to the inner peripheral surfaces of the leading outer shell 21A and the trailing outer shell 22A. The creation of frozen soil 25 in this step is performed over the entire outside of the leading outer shell 21A and the trailing outer shell 22A, that is, the entire outside of the outer shell 20A of the shield tunnel 20. By creating the frozen soil 25 over the entire outside of the outer shell 20A in this way, it becomes possible to prevent groundwater from flowing into the shield tunnel 20 in the next step.

Next, with reference to FIG. 4(A), a process of forming the steel plate concrete structure 30 within the outer shell 20A will be described.

In this process, first, a part of the trailing outer shell 22A separating the leading shield tunnel 21 and the trailing shield tunnel 22 is removed, and the internal space of the leading shield tunnel 21 and the internal space of the trailing shield tunnel 22 are removed. A communication opening is formed to communicate with the As mentioned above, since frozen soil 25 is created around the shield tunnel 20, groundwater will not flow into the leading shield tunnel 21 and trailing shield tunnel 22 even if a communicating opening is formed. Prevented.

Then, a steel structure assembled with steel materials is placed in the space inside the shield tunnel 20, which has become an annular space due to the formation of the communication opening, and further, inside the shield tunnel 20 in which the steel structure is placed. By pouring concrete, an annular steel plate concrete structure 30 is constructed within the outer shell 20A.

When the concrete placed inside the shield tunnel 20 hardens and the steel plate concrete structure 30 and the shield tunnel 20 become an integrated skeleton, the outer skeleton 15 is constructed as shown in FIG. 4(B). Ru.

When the outer shell 15 is constructed, as shown in FIG. 4(B), the supply of refrigerant to the freezing tubes is sequentially stopped in the part where the outer shell 15 is constructed, and the cryogenic pipes formed on the outside of the outer shell 20A are stopped. The frozen soil 25 is gradually thawed.

When the thawing of the frozen soil 25 is completed, excavation within the outer shell 15 is performed as shown in FIG. 4(C). In this step, the underground cavity 14 is formed within the outer shell 15 by gradually excavating the interior of the outer shell 15 from above to below.

Through the above steps, as shown in FIG. 2, a large cross-section tunnel 10 including an outer shell 15 that forms the outer shell of the underground cavity 14 is constructed.

Next, with reference to FIGS. 5 and 6, the configuration of the preceding shield tunnel 21 when creating frozen soil 24, 25 around the preceding shield tunnel 21 in the step of constructing the large cross-section tunnel 10 described above will be described. FIG. 5 is a front view schematically showing an example of the segment ring 40 constituting the leading outer shell 21A of the leading shield tunnel 21, viewed from the tunnel axis direction, and FIG. 6 is a front view shown by arrow B in FIG. FIG. 4 is a developed view of the segment ring 40 viewed in the direction. In addition, in FIG. 5, the circle indicated by a broken line indicates the outer edge of the trailing shield tunnel 22 constructed adjacent to the preceding shield tunnel 21, and the portion of the preceding shield tunnel 21 displayed within this broken line circle is cut by the trailing shield excavator when the trailing shield tunnel 22 is constructed, and is discharged and removed from the trailing shield excavator along with the excavated soil.

As shown in FIGS. 5 and 6, the segment ring 40 constituting the preceding shield tunnel 21 is an annular body formed by assembling a plurality of segment pieces 41 and 42 in an annular shape along the circumferential direction of the tunnel, The plurality of segment rings 40 are connected in the axial direction of the tunnel to form a leading outer shell 21A which is a lining covering the inner circumferential surface of the leading excavation shaft (tunnel, pit) 21B.

In creating the frozen soil 24, 25, a freezing pipe 45 is attached to the inner peripheral surface 40A of the segment ring 40 along the axial direction of the tunnel. When a vaporized refrigerant such as liquefied carbon dioxide is flowed into the freezing pipe 45, the ground facing the outer peripheral surface 40B of the segment ring 40 is cooled via the segment ring 40, and a certain thickness of soil is frozen from the outer peripheral surface 40B. Frozen soil is created.

In addition, in the above-mentioned process, when creating frozen soil 24 on a part of the outer periphery of the leading outer shell 21A before the trailing shield tunnel 22 is constructed, the frozen soil 24 includes the part cut by the trailing shield excavator. Refrigerant is flowed into a freezing tube 45 attached to a range, for example, a range indicated as "refrigerant supply range 1" in FIG. In addition, the refrigerant is flowed into the freezing pipe 45 attached to the range indicated as "refrigerant supply range 2", which is indicated as the boundary between the area where the trailing shield tunnel 22 is planned to be constructed and the leading outer shell 21A. Frozen soil 24 is created around the boundary.

After that, when constructing the outer shell 15, the parts that were not cut by the trailing shield excavator, that is, the freezing pipe 45 attached outside the circle indicated by the broken line in FIG. 5, and the trailing shield A refrigerant is flowed through a freezing pipe (not shown) attached to the tunnel 22, and frozen soil 25 is created outside the outer shell 20A of the shield tunnel 20.

Here, among the segment pieces 41 and 42 constituting the segment ring 40 of the preceding shield tunnel 21, the segment piece 41 disposed at a position to be cut by the trailing shield excavator is formed of a material containing at least concrete. Made of machinable concrete. Note that the segment piece 41 may be made of reinforced concrete containing steel materials such as reinforcing bars, as long as it can be cut. Moreover, the segment piece 42 arranged at a position not cut by the trailing shield excavator can be made of highly rigid steel. Note that all the segment pieces constituting the segment ring of the trailing shield tunnel 22 that are not cut can be made of steel.

The segment piece 41 made of reinforced concrete has lower heat conductivity than the segment piece 42 made of steel because its main raw material is concrete made of aggregate or cement. For this reason, when a refrigerant is passed through the freezing tube 45 attached to the inner peripheral surface of the reinforced concrete segment piece 41 and the temperature of the surrounding ground is lowered to create frozen soil, the heat transfer efficiency is poor, for example. , it takes a relatively long time for frozen soil to develop.

Therefore, if it is necessary to create frozen soil outside the reinforced concrete segment piece 41, the start of the next process, which is to be carried out after sufficiently strong frozen soil has been created, will be delayed, the construction period will be longer, and as a result, the construction cost will be increased. may increase.

Therefore, in this embodiment, even if the segment piece 41 made of reinforced concrete is used, in order to efficiently create frozen soil on the outside thereof, the segment piece 41 made of reinforced concrete is constructed using a freezing construction method having the following configuration. segment 100 is adopted.

As shown in FIGS. 7 and 8, the segment 100 for freezing construction method (hereinafter referred to as "segment 100") includes a main body 50 formed of reinforced concrete, and a segment 100 that is provided inside the main body 50 and is larger than the main body 50. This is a segment piece that includes a heat conductive portion 52 having high thermal conductivity. FIG. 7 is a cross-sectional view taken along the line CC in FIG. 6, and is a cross-sectional view of the segment 100 in a plane orthogonal to the tunnel axis direction. Moreover, FIG. 8 is a view of the segment 100 viewed in the direction indicated by arrow D in FIG. 7, and is a view showing a curved surface along the circumferential direction of the tunnel developed into a planar shape.

The main body portion 50 has an outer circumferential surface 50A facing the inner circumferential surface of the preceding excavation shaft (tunnel, pit) 21B, and an inner circumferential surface 50B to which the freezing pipe 45 is attached. It is formed into a circular arc shape.

The heat conduction portion 52 includes an extension portion 53 that extends from a position facing the freezing tube 45 toward the outer circumferential surface 50A on the inner circumferential surface 50B side of the main body portion 50, and an extension portion 53 that covers the outer circumferential surface 50A of the main body portion 50. It is a metal member having a plate-shaped exposed portion 54 provided on the surface of the main body portion 50. The thermally conductive part 52 is embedded in the main body part 50 when the main body part 50 is formed, and is formed integrally with the main body part 50.

The material constituting the heat conductive part 52 may be any metal as long as it has a higher thermal conductivity than the main body part 50, and may be general steel. Note that, as described above, the segment 100 in which the thermally conductive part 52 is provided is a segment piece that is placed in the part to be cut, so the material constituting the thermally conductive part 52 may be, for example, copper or aluminum. Use metals with good machinability, their oxides (copper oxide, alumina), alloys containing these (brass, duralumin, etc.), and free-cutting steel such as SUM, which is a steel material with relatively excellent machinability. is preferred.

The extending portion 53 is exposed from the main body portion 50 on the inner circumferential surface 50B side of the main body portion 50, and a contact surface 53A as a contact portion with which the freezing tube 45 comes into contact is formed in the exposed portion. Further, as shown in FIG. 8, the extending portion 53 is formed to extend along the axial direction of the tunnel, that is, the direction in which the freezing tube 45 is attached. That is, the extending portion 53 is formed into a flat plate shape that extends along the radial direction of the tunnel and also extends along the axial direction of the tunnel. Further, the extending portion 53 is provided with a fastening portion (not shown) for fastening the extending portion 53 to the reinforcing bars that constitute the main body portion 50 . Note that, in order to improve the machinability of the segments 100, it is preferable to use a fiber-reinforced resin material such as fiber-reinforced plastic instead of reinforcing bars as the reinforcing bars provided in the main body portion 50.

The heat conduction part 52 provided in the segment 100 in this way has an exposed part 54 that faces the inner peripheral surface of the preceding excavation shaft (tunnel, pit) 21B by being arranged on the surface of the main body part 50, and one end. has an extension part 53 that is coupled to the exposed part 54 and whose other end is in contact with the freezing pipe 45. Therefore, the ground facing the exposed part 54 is connected to the ground through the exposed part 54 and the extension part 53, which have high thermal conductivity. The cold heat of the refrigerant passing through the freezing tube 45 is efficiently transferred. In other words, the heat of the ground facing the exposed portion 54 is absorbed by the exposed portion 54 and efficiently radiated to the refrigerant flowing in the freezing tube 45 via the extension portion 53. Therefore, the temperature of the ground outside the segment 100 is quickly reduced by flowing the refrigerant through the freezing pipe 45.

Further, while the exposed area of the exposed portion 54 exposed on the outer circumferential surface 50A side of the main body portion 50 is increased, the exposed area of the extension portion 53 exposed on the inner circumferential surface 50B side of the main body portion 50 is in contact with the freezing tube 45. By restricting the size to a size sufficient to allow the exposed portion 54 to contact almost only the frozen tube 45, the heat exchange efficiency between the ground facing the exposed portion 54 and the refrigerant in the frozen tube 45 that the extension portion 53 contacts is improved. By improving the ground temperature, it is possible to efficiently lower the temperature of the ground over a wider range.

Therefore, by using the segment 100 with the above configuration as the segment piece 41 that is placed in the position to be cut by the trailing shield excavator among the segment pieces 41 and 42 that constitute the segment ring 40 of the leading shield tunnel 21, Frozen soil can be efficiently created on the outside of the segment piece 41, and the leading outer shell 21A can be easily cut by the trailing shield excavator. Note that the thickness of the extension portion 53 provided within the segment 100 in the tunnel circumferential direction is preferably thick in order to improve the cooling performance of the ground, but it is better to be thin in order to improve the machinability of the segment 100. It's better to do so. Therefore, the thickness of the extending portion 53 is set in consideration of these balances.

Next, a freezing construction method using the segment 100 having the above configuration will be described, taking as an example the case where frozen soil 24 and 25 are created when constructing the large cross-section tunnel 10 described above.

As shown in FIG. 3(A), when partially creating frozen soil 24 around the preceding shield tunnel 21, first, the circumferential direction and Segment pieces 41 and 42 are assembled along the axial direction, as shown in FIGS. 5 and 6. In addition, as the segment piece 42 made of reinforced concrete, the segment 100 having the above structure, which is a segment for freezing construction method, is used.

Next, a tunnel is created on the inner circumferential surface of the segment 100 and the steel segment piece 41 located within an area where it is necessary to create frozen soil 24, for example, an area indicated as a "refrigerant supply area" in FIG. A freezing tube 45 is attached along the axial direction.

Subsequently, the refrigerant is flowed into the freezing tube 45 installed in the preceding shield tunnel 21. The cold heat of the refrigerant flowing within the freezing tube 45 is transmitted to the ground outside the segment 100 through the heat conduction portion 52 within the segment 100. Note that the cold heat of the refrigerant flowing in the freezing tube 45 attached to the steel segment piece 41 is transmitted to the ground through the segment piece 41.

As a result, frozen soil 24 is quickly created over a predetermined range outside the preceding shield tunnel 21 to which the segment 100 having the above configuration is partially applied.

On the other hand, as shown in FIG. 3(C), when creating frozen soil 25 around the leading shield tunnel 21 and the trailing shield tunnel 22, first, the leading excavation shaft (tunnel, pit) excavated by the leading shield tunneling machine is Segment pieces 41 and 42 are assembled along the circumferential and axial directions of 21B, as shown in FIGS. 5 and 6. In addition, as the segment piece 42 made of reinforced concrete, the segment 100 having the above structure, which is a segment for freezing construction method, is used.

Next, the trailing shield tunnel 22 is constructed by cutting the portion of the leading shield tunnel 21 assembled by the segments 100 having the above configuration using the trailing shield excavator.

Then, along the axial direction of the tunnel, the inner peripheral surface of the steel segment piece 41 of the leading shield tunnel 21 and the inner peripheral surface of the segment 100 that remained uncut when constructing the trailing shield tunnel 22 is cut. The freezing tube 45 is attached. Further, a freezing tube 45 is also attached to the inner peripheral surface of the constructed trailing shield tunnel 22 along the axial direction of the tunnel.

Subsequently, the refrigerant is flowed into the freezing tubes 45 installed in the leading shield tunnel 21 and the trailing shield tunnel 22. The cold heat of the refrigerant flowing within the freezing tube 45 is transmitted to the ground outside the segment 100 through the heat conduction portion 52 within the segment 100. Note that the cold heat of the refrigerant flowing in the freezing tube 45 attached to the steel segment piece 41 is transmitted to the ground through the segment piece 41. Further, the cold heat of the refrigerant flowing in the freezing pipe 45 attached to the trailing shield tunnel 22 is transmitted to the ground through the steel segment pieces that constitute the trailing outer shell 22A.

As a result, frozen soil 25 is quickly created on the outside of the preceding shield tunnel 21 and the outside of the trailing shield tunnel 22, to which the segment 100 having the above configuration is partially applied.

According to the above embodiment, the following effects are achieved.

The segment 100 described above includes a main body 50 formed of reinforced concrete, and a heat conductive part 52 that is at least partially provided inside the main body 50 and has a higher thermal conductivity than the main body 50. 52 extends from a position facing the freezing tube 45 on the inner circumferential surface 50B side of the main body portion 50 toward the outer circumferential surface 50A. By providing the heat conduction part 52 in the main body part 50 formed of reinforced concrete in this way, which can efficiently transmit the cold heat of the refrigerant flowing inside the freezing tube 45 toward the outer circumferential surface 50A of the main body part 50, It becomes possible to efficiently cool the ground outside the segment 100, and as a result, frozen ground can be efficiently created around the preceding shield tunnel 21.

In addition, by making it possible to efficiently and quickly create frozen soil around the preceding shield tunnel 21, it becomes possible to start the next process of work earlier, which is to be carried out after sufficiently strong frozen soil has been created. As a result, the construction period can be shortened and construction costs can be reduced.

Next, a modification of the above embodiment will be described. The following modified examples are also within the scope of the present invention, and it is also possible to combine the configuration shown in the modified example with the configuration described in the above embodiment, or to combine the configurations described in the following different modified examples. It is.

In the embodiment described above, the heat conductive part 52 is made of metal. Alternatively, the thermally conductive portion 52 may be a structure pre-formed from a material that has higher thermal conductivity than the main body portion 50 and has thermal conductivity equivalent to that of metal, for example, concrete containing carbon nanofibers. It's okay. In this way, by containing a material with high thermal conductivity, it becomes possible to efficiently transfer the cold heat of the refrigerant flowing inside the freezing tube 45 toward the outer circumferential surface 50A of the main body part 50, and the heat conductive part 52 By using concrete as the main material, it is possible to improve the machinability of the segment 100.

Further, in the embodiment described above, the heat conductive portion 52 is exposed on the outer circumferential surface 50A side of the main body portion 50 and the inner circumferential surface 50B side of the main body portion 50, and is disposed on the surface of the main body portion 50. Alternatively, the heat conduction part 52 may be a flat plate member 55 that is not exposed from the main body part 50, as in the first modification shown in FIG. It is sufficient that it extends from a position facing the freezing tube 45 toward the outer circumferential surface 50A. If it extends toward the outer circumferential surface 50A from the position facing the freezing pipe 45 in this way, similarly to the above embodiment, the cold heat of the refrigerant flowing inside the freezing pipe 45 can be efficiently transferred to the ground outside the segment 100. It is possible to communicate well. Note that the flat plate member 55 may be exposed on either the outer circumferential surface 50A side or the inner circumferential surface 50B side of the main body portion 50.

Further, in the above embodiment, the exposed portion 54 of the heat conductive portion 52 that is disposed on the surface of the main body 50 and exposed on the outer peripheral surface 50A side of the main body 50 is formed in a plate shape that covers the outer peripheral surface 50A of the main body 50. has been done. Instead, the exposed portion 54 is formed in a lattice shape having a portion 54A extending along the axial direction of the tunnel and a portion 54B extending along the circumferential direction of the tunnel, as in a second modification shown in FIG. may have been done. In this case as well, as in the above embodiment, the exposed area of the exposed portion 54 exposed on the outer circumferential surface 50A side of the main body portion 50 becomes large, so that the area inside the freezing tube 45 where the extension portion 53 contacts the ground facing the exposed portion 54 increases. The heat exchange efficiency with the refrigerant is improved, and as a result, the temperature of the ground over a wider range can be efficiently lowered. Furthermore, compared to the case where the outer circumferential surface 50A of the main body portion 50 is covered, the range in which the metal exposed portion 54 is provided is reduced, so that the machinability of the segment 100 can be improved.

Furthermore, in the above embodiment, since the freezing tube 45 is arranged along the axial direction of the tunnel, the extension part 53 of the heat conduction part 52 is provided along the axial direction of the tunnel. . The direction in which the freezing tube 45 is arranged is not limited to the axial direction of the tunnel, but may be the circumferential direction of the tunnel. When the freezing tube 45 is arranged along the circumferential direction of the tunnel, the direction in which the freezing tube 45 is arranged is The extending portion 53 is provided along the circumferential direction of the tunnel in accordance with this.

Furthermore, in the above embodiment, before constructing the trailing shield tunnel 22, the frozen soil 24 is created around the leading shield tunnel 21, but when the trailing shield tunnel 22 is constructed, the trailing shield tunnel 22 is If the preceding shield tunnel 21 is provided with a structure capable of preventing groundwater from flowing into the tunnel, it is not necessary to create the frozen soil 24.

Although the embodiments of the present invention have been described above, the above embodiments merely show a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments. do not have.

In the above embodiment, the frozen construction method segment 100 is used as the segment piece 41 that becomes the lining of the preceding excavation shaft (tunnel, pit) 21B. It is not limited. Freezing construction segments are installed in locations where it is necessary to freeze the ground in structures built underground, and create frozen soil on the outer circumferential surface by flowing refrigerant through freezing pipes attached to the inner circumferential surface. For example, it may be a segment used in a pneumatic caisson construction method or an underground continuous wall construction method, and used in a lining body constituting an underground wall surface of a shaft. Moreover, the segment 100 for freezing construction method is composed of a plurality of segment pieces 41 and 42, and the segment ring 40 is constituted by the plurality of segments 100 for freezing construction method, but one segment for freezing construction method forms the segment ring 40. You can leave it there. Further, on the underground wall surface of the shaft, a plurality of freezing segments may form a ring-shaped lining, or one freezing segment may form a ring-shaped lining.

100... Segment for frozen construction method, 10... Large cross-section tunnel (underground structure), 11... Main line shield tunnel, 12... Lamp shield tunnel, 14... Underground cavity, 15... Outer shell Frame, 20... Shield tunnel, 20A... Outer shell, 21... Preceding shield tunnel (shield tunnel), 21A... Preceding outer shell (outer shell, lining), 21B... Preliminary excavation Pit (tunnel, pit), 22... Trailing shield tunnel (shield tunnel), 22A... Trailing outer shell (outer shell), 22B... Trailing excavation shaft (tunnel), 24... Frozen ground (Frozen soil), 25... Frozen soil (frozen soil), 30... Steel plate concrete structure, 40... Segment ring, 41... Segment piece, 42... Segment piece, 45... Frozen Pipe, 50... Body part, 50A... Outer peripheral surface, 50B... Inner circumferential surface, 52... Heat conduction part, 53... Extension part, 53A... Contact surface (contact part) , 54... exposed portion, 55... flat plate member

Claims (6)

A frozen construction method segment that is assembled along the circumferential and axial directions of a mine constructed underground and serves as a lining body,
a main body formed of at least concrete and having an outer circumferential surface facing the pit and an inner circumferential surface to which a freezing pipe is attached;
a heat conductive part provided in the main body and having a higher thermal conductivity than the main body,
The heat conduction part is arranged at least at a position facing the freezing tube on the inner peripheral surface side, and extends from the position toward the outer peripheral surface.
Segment for freezing method. The tunnel constructed underground is a shield tunnel.
The segment for freezing construction method according to claim 1. The thermally conductive part is formed of metal or concrete containing a material with higher thermal conductivity than the main body part.
The segment for freezing construction method according to claim 1 or 2. The thermally conductive portion is disposed on the surface of the main body portion on at least one of the inner circumferential surface side and the outer circumferential surface side.
The segment for freezing construction method according to any one of claims 1 to 3. A freezing construction method using the freezing construction method segment according to any one of claims 1 to 4,
assembling the frozen construction method segments along the circumferential and axial directions of the pit constructed underground;
a step of attaching the freezing pipe to the inner circumferential surface of the freezing construction method segment along the circumferential direction or axial direction of the pit;
flowing a refrigerant through the freezing tube;
Freezing method. The pit in which the frozen construction method segments are assembled is a leading shield tunnel, and the method further includes the step of constructing a trailing shield tunnel while cutting a part of the leading shield tunnel.
The freezing method according to claim 5.