Methods for freezing the ground

Abstract

To achieve good adhesion between frozen soil and a shield tunnel.SOLUTION: A method of freezing the ground includes, when constructing a shield tunnel 10 with a shield machine 1, filling between tail brushes 21 of the shield machine 1 with a filling material (e.g., tail grease 22) and filling tail void 31 behind the tail brush 21 with backfill material 35 (step S1), cleaning at least the area between an outer peripheral surface 33 of the shield tunnel 10 and the backfill material 35 in the tail void 31 (step S2), and, after this cleaning, freezing the ground around the shield tunnel 10 together with the backfill material 35 in the tail void 31 (step S3).SELECTED DRAWING: Figure 3

Description

[[Technical Field]]

[0001] The present invention relates to a method for freezing the ground around a shield tunnel. [[Background Art]]

[0002] The shield method can be cited as an example of construction methods used when constructing a tunnel in the ground. In the shield method, for example, a starting shaft and an arrival shaft are constructed in the natural ground, and while excavating the natural ground from the starting shaft toward the arrival shaft with a shield machine (shield tunneling machine), segments are successively assembled in the circumferential direction of the tunnel at the rear of the shield machine to construct a segment ring, and adjacent segment rings are connected to each other in the axial direction of the tunnel to construct a cylindrical lining body (shield tunnel). In this construction method, the shield machine presses the existing segment ring behind it backward with a propulsion jack, and advances while excavating the natural ground by the thrust generated as a reaction force. In addition, in the rear part of a general shield machine, tail grease is filled between tail brushes, and by applying this tail grease to the outer peripheral surface of the shield tunnel with the tail brushes, the water stopping performance against groundwater at the rear of the shield machine is ensured. Furthermore, the tail void behind the tail brushes is filled with backfill material.

[0003] Patent Document 1 discloses a method for freezing the ground around a shield tunnel as an example of a ground freezing method. In Patent Document 1, the ground and backfill material around the shield tunnel are frozen by circulating a coolant through freezing pipes provided in segments constituting the shield tunnel (see paragraph 0052 and the like of Patent Document 1). [[Prior Art Documents]] [[Patent Documents]]

[0004] [[Patent Document 1]] Japanese Unexamined Patent Publication No. 2008-069246 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0005] However, the aforementioned applied tail grease may remain on the outer surface of the shield tunnel (in other words, the outer surface of the segments and the outer surface of the segment rings) even after the shield machine has passed through.

[0006] In this regard, for example, when widening an underground shield tunnel, if the ground freezing method is adopted as an auxiliary construction method, the freeze-setting strength (e.g., freeze-setting shear strength) at the interface between the frozen soil (the aforementioned frozen ground and backfill material) and the shield tunnel is relied upon. However, if tail grease is present at this interface, there is a risk that the freeze-setting strength at that interface will decrease accordingly.

[0007] In view of these circumstances, the present invention aims to achieve good freezing between frozen soil and shield tunnels. [Means for solving the problem]

[0008] Therefore, in the first embodiment of the present invention, the method for freezing the ground is When constructing a shield tunnel with a shield machine, filler material is filled between the tail brushes of the shield machine, and backfill material is filled into the tail void behind the tail brushes. At a minimum, the area between the outer surface of the shield tunnel and the backfill material in the tail void shall be cleaned, and After the cleaning is performed, the ground surrounding the shield tunnel is frozen together with the backfill material in the tail void. Includes fruit, The cleaning process includes injecting a cleaning solution containing a surfactant between the outer surface of the shield tunnel and the backfill material in the tail void. .

[0009] In a second embodiment of the present invention, the method for freezing the ground is: When constructing a shield tunnel with a shield machine, filler material is filled between the tail brushes of the shield machine, and backfill material is filled into the tail void behind the tail brushes. At a minimum, the area between the outer surface of the shield tunnel and the backfill material in the tail void shall be cleaned, and Prior to the aforementioned cleaning, the ground surrounding the shield tunnel is frozen together with the backfill material in the tail void. Includes fruit, The cleaning process includes injecting a cleaning solution containing a surfactant between the outer surface of the shield tunnel and the backfill material in the tail void. . [Effects of the Invention]

[0010] According to the present invention, the packing material such as tail grease remaining between the outer surface of the shield tunnel and the backfill material in the tail void can be reduced or removed by the aforementioned cleaning, thereby enabling good freezing between the frozen soil and the shield tunnel. [Brief explanation of the drawing]

[0011] [Figure 1] Schematic diagram of the shield machine in the first embodiment of the present invention [Figure 2] A diagram showing the application status of tail grease in the first embodiment. [Figure 3] Flowchart showing the ground freezing method in the first embodiment described above. [Figure 4] A diagram showing the schematic configuration of the cleaning system in the first embodiment. [Figure 5] A diagram showing an example of the cleaning method in the first embodiment. [Figure 6] A diagram showing an example of the cleaning method in the first embodiment. [Figure 7] Flowchart showing a ground freezing method in a second embodiment of the present invention [Figure 8] This figure shows the schematic configuration of the gap-filling material filling system in the second embodiment. [Figure 9] A diagram showing an example of the cleaning and gap-filling method in the second embodiment. [Figure 10] A diagram showing an example of the cleaning and gap-filling method in the second embodiment. [Figure 11]Flow chart showing the ground freezing method according to the third embodiment of the present invention [Figure 12] Flow chart showing the ground freezing method according to the fourth embodiment of the present invention Mode for Carrying Out the Invention

[0012] Embodiments of the present invention will be described below based on the drawings.

[0013] Figure 1 is a diagram showing a schematic configuration of a shield machine (shield tunneling machine) 1 according to the first embodiment of the present invention. In the present embodiment, for convenience, front, rear, left and right are defined with the tunnel tunneling direction as the forward direction. In the present embodiment, the configuration of the shield machine will be described by taking a so-called mud pressure type shield machine as an example, but the type of shield machine is not limited to this.

[0014] The shield machine 1 used for constructing a shield tunnel 10 comprises a cylindrical (for example, cylindrical) skin plate 2 forming the main body thereof, an excavation cutter head 3 provided at the front end of the skin plate 2, and a shield bulkhead 4 spaced apart behind the cutter head 3 and disposed on the skin plate 2.

[0015] The cutter head 3 is rotatably supported by the shield bulkhead 4. The cutter head 3 excavates the natural ground while rotating, using a drive motor 5 installed on the rear surface of the shield bulkhead 4 as a drive source. Between the cutter head 3 and the shield bulkhead 4, a cutter chamber 6 is defined and formed by these components and the skin plate 2. Excavated sediment generated by excavation with the cutter head 3 stays in the cutter chamber 6. The excavated sediment in the cutter chamber 6 is carried out to the rear of the shield bulkhead 4 by sediment conveying means such as a screw conveyor 7.

[0016] The shield machine 1 is equipped with an erector device 8 within the skin plate 2 behind the cutter head 3 and shield bulkhead 4. The erector device 8 is equipped with a gripping part 9. The erector device 8 can grip a segment S having an arc-shaped cross-section (e.g., a circular arc-shaped cross-section) with the gripping part 9 and move the segment S as appropriate in the tunnel inward / outward direction (e.g., tunnel radial direction), tunnel circumferential direction, and tunnel axial direction. Within the skin plate 2, the erector device 8 constructs a segment ring SR by connecting a plurality of segments S along its circumferential direction. Then, by sequentially constructing this segment ring SR in the tunnel axial direction, a shield tunnel 10 consisting of a cylindrical (e.g., cylindrical) lining body is constructed. The segment S may be made of, for example, steel or concrete. In other words, the segment S may be, for example, a steel segment, an RC segment, or a composite segment.

[0017] Inside the skin plate 2 of the shield machine 1, multiple propulsion jacks 11 are arranged circumferentially along the inner surface of the skin plate 2, spaced apart from each other. Each propulsion jack 11 is a hydraulic jack consisting of a cylinder 12 and a rod 13. One end of the cylinder 12 is fixed to the skin plate 2, and the other end allows the rod 13 to extend and retract. By extending the propulsion jack 11 with the tip of the rod 13 of the propulsion jack 11 in contact with the existing segment S, the shield machine 1 can obtain thrust. In this way, the propulsion jack 11 takes a reaction force from the existing segment S to propel the shield machine 1.

[0018] The tail portion (rear end) 2a of the skin plate 2 is provided with multiple rows (three rows in Figure 1) of tail brushes 21 along its outer edge. The arrangement of the tail brushes 21 is not limited to three rows as shown in Figure 1; any number of rows (two or more) can be arranged. Each row of tail brushes 21 is ring-shaped and follows the inner circumferential surface of the tail portion 2a of the skin plate 2. The ring-shaped tail brushes 21 in each row are spaced apart from one another in the front-to-back direction. The tail brushes 21 are, for example, metal brushes (wire brushes). However, the tail brushes 21 are not limited to metal; they may be made of resin such as urethane.

[0019] Tail grease 22 is filled between the ring-shaped tail brushes 21, which are arranged at intervals in the front-to-back direction. Here, tail grease 22 is an example of the "filler material filled between tail brushes" of the present invention. Tail grease 22 contains oil and grease.

[0020] As the shield machine 1 excavates (advances), the tail brush 21 moves along the outer surface of the shield tunnel 10 (in other words, the outer surface of the segment S and the outer surface of the segment ring SR) while in contact with it. During this movement, the tail brush 21 can apply tail grease 22 to the outer surface of the shield tunnel 10.

[0021] The shield machine 1 has a tail seal portion 23 at the tail portion 2a of the skin plate 2, which includes a tail brush 21 and tail grease 22. This prevents soil, water, and other debris from the surrounding ground from flowing into the shield machine 1 from between the inner surface of the skin plate 2 and the outer surface of the shield tunnel 10.

[0022] Figure 2 shows the application status of the tail grease 22 and corresponds to part P in Figure 1.

[0023] When constructing a shield tunnel 10 using a shield machine 1, a tail void 31 is formed due to the difference between the outer diameter of the shield tunnel 10 (in other words, the outer diameter of the segment ring SR) and the outer diameter of the excavation by the shield machine 1. Here, the tail void 31 is, for example, a void that occurs between the excavation surface (the tunnel wall surface which is the exposed surface of the surrounding ground G) 32 formed by the excavation of the shield machine 1 and the outer circumferential surface 33 of the shield tunnel 10. Backfill material 35 is filled into the tail void 31. The backfill material 35 is, for example, a cement-based filler. Alternatively, the backfill material 35 may be, for example, a fluid solidifying agent containing cement and water glass. It is preferable that the equipment for injecting the backfill material 35 (backfill material injection equipment) is equipped on the shield machine 1.

[0024] The tail grease 22 applied to the outer surface 33 of the shield tunnel 10 by the tail brush 21 may remain on the outer surface 33 of the shield tunnel 10 even after passing through the shield machine 1. In this regard, Figure 2 illustrates this remaining tail grease 22a. The thickness of this remaining tail grease 22a is, for example, about 1 mm. In this embodiment, in order to reduce or remove this remaining tail grease 22a, at least the area between the outer surface 33 of the shield tunnel 10 and the backfill material 35 in the tail void 31 (boundary C) is cleaned. A cleaning system 40 (see Figure 4), which will be described later, may be used for this cleaning.

[0025] Next, the ground freezing method in this embodiment, which includes this cleaning step, will be explained using Figures 3 to 6, in addition to Figures 1 and 2 mentioned above. Figure 3 is a flowchart showing the ground freezing method in this embodiment. Figure 4 is a diagram showing the schematic configuration of the cleaning system 40. Figures 5(a) to 6(d) show examples of the cleaning method in this embodiment. Furthermore, this ground freezing method can be used as an auxiliary construction method, for example, when widening the underground section of a shield tunnel 10.

[0026] First, in relation to step S1 of the ground freezing method shown in Figure 3, when constructing the shield tunnel 10 with the shield machine 1, tail grease 22 is filled between the tail brushes 21 of the shield machine 1. In addition, backfill material 35 is filled into the tail void 31 formed behind the tail brushes 21 as the shield machine 1 excavates, using the backfill material injection equipment mentioned above. Tail grease 22a remains between the backfill material 35 filled in the tail void 31 and the outer surface 33 of the shield tunnel 10 (boundary C) (see Figure 2).

[0027] Next, in step S2 of the ground freezing method shown in Figure 3, the area between the backfill material 35 filled in the tail void 31 and the outer surface 33 of the shield tunnel 10 (boundary C) is cleaned using the cleaning system 40.

[0028] As shown in Figure 4, the cleaning system 40 comprises a cleaning fluid injection system 41 and a waste liquid recovery system 42. The cleaning fluid injection system 41 is configured to eject cleaning fluid from an injection nozzle 45 located at the tip of an injection pipe 44 by the operation of a high-pressure ejector 43. The waste liquid recovery system 42 is configured to collect waste liquid in a waste liquid tank 49 by sucking it from the tip 48 of a discharge pipe 47 by the operation of a vacuum pump 46. Here, the cleaning fluid includes, for example, water and a surfactant.

[0029] The shield tunnel 10 is provided with a first through-hole 51 and a second through-hole 52. The first through-hole 51 and the second through-hole 52 each penetrate the shield tunnel 10 from the inside to the outside. An injection pipe 44 is inserted into the first through-hole 51 from inside the shield tunnel 10. A discharge pipe 47 is inserted into the second through-hole 52 from inside the shield tunnel 10. At least one of the first through-hole 51 and the second through-hole 52 may be provided in the segment S prior to the assembly of the segment S by the erector device 8, or it may be provided after the assembly of the segment S (after the construction of the shield tunnel 10 consisting of the lining).

[0030] Furthermore, the first through-hole 51 and the second through-hole 52 are each provided with a water-stopping means (not shown), such as a water-stopping valve. Therefore, even when the injection pipe 44 is inserted into the first through-hole 51, water-stopping can be ensured by the water-stopping means, and even when the discharge pipe 47 is inserted into the second through-hole 52, water-stopping can be ensured by the water-stopping means.

[0031] The injection nozzle 45 is oriented perpendicular to the direction of extension of the injection pipe 44. Furthermore, the injection nozzle 45 is rotatably mounted on the injection pipe 44, with the injection pipe 44's central axis as its pivot point. The arrow indicated by the symbol R in Figure 4 indicates that the injection nozzle 45 is rotatable. The injection pipe 44 is inserted into the first through-hole 51 from inside the shield tunnel 10 such that the injection nozzle 45 at its tip faces the aforementioned boundary C. The aforementioned high-pressure injection machine 43 is located inside the shield tunnel 10.

[0032] The discharge pipe 47 is inserted into the second through-hole 52 from inside the shield tunnel 10 such that its tip 48 faces the aforementioned boundary C. The vacuum pump 46 and waste liquid tank 49 are located inside the shield tunnel 10.

[0033] In step S2 described above, in the cleaning fluid injection system 41, while operating the high-pressure sprayer 43, the spray nozzle 45 is rotated relative to the injection pipe 44 and the cleaning fluid is sprayed toward the boundary C described above, thereby flushing away the tail grease 22a remaining at the boundary C (i.e., reducing or removing the tail grease 22a). Here, since the cleaning fluid contains a surfactant, it can emulsify the tail grease 22a and increase its fluidity, and as a result, the removal of the tail grease 22a can be promoted.

[0034] The waste liquid containing tail grease 22a that is pushed away along with the cleaning liquid by the spray nozzle 45 is collected in the waste liquid tank 49 by operating the vacuum pump 46 of the waste liquid collection system 42, which sucks the waste liquid from the aforementioned boundary C through the tip 48 of the discharge pipe 47. As this waste liquid is collected, the cleaning liquid gradually permeates into the boundary C. At this point, the operation of the cleaning system 40 may be stopped when the content of tail grease 22a in the waste liquid collected in the waste liquid tank 49 falls below a predetermined value.

[0035] Figure 4 shows an arrangement in which the injection pipes 44 (first through-hole 51) and discharge pipes 47 (second through-hole 52) are arranged alternately and spaced apart along the tunnel axis. However, the injection pipes 44 (first through-hole 51) and discharge pipes 47 (second through-hole 52) may also be arranged alternately and spaced apart along the tunnel circumferential direction. Furthermore, in the unfolded view of the shield tunnel 10, the injection pipes 44 (first through-hole 51) and discharge pipes 47 (second through-hole 52) may be arranged alternately and spaced apart in a matrix or staggered pattern. In any case, the injection pipes 44 (first through-hole 51) and discharge pipes 47 (second through-hole 52) can be appropriately arranged so that the wastewater generated by the operation of the cleaning fluid injection system 41 can be efficiently recovered by the wastewater recovery system 42.

[0036] Regarding the cleaning in step S2 described above, it is preferable to divide the tunnel circumferentially into several regions and proceed with cleaning sequentially from the lower region (high-pressure side region) to the upper region (low-pressure side region). In this regard, Figures 5(a) to 6(d) show an example of this cleaning method.

[0037] First, as shown in Figures 5(a) and (b), the region A1 at the aforementioned boundary C is cleaned by cleaning with the cleaning system 40 using the first through-hole 51a at the lowest end.

[0038] Next, as shown in Figure 6(c), the areas A2 and A3 at the aforementioned boundary C are cleaned by cleaning using the cleaning system 40, which utilizes the first through-hole 51b in the lower left and the first through-hole 51c in the lower right. Note that the cleaning in these areas A2 and A3 may reach the upper part of the aforementioned area A1.

[0039] Next, as shown in Figure 6(E), the area A4 at the aforementioned boundary C is cleaned by cleaning with the cleaning system 40, using the first through-hole 51d in the upper left, the first through-hole 51e in the upper right, and the first through-hole 51f at the top end. Note that this cleaning in area A4 may reach the upper part of the aforementioned areas A2 and A3.

[0040] As described above, the cleaning in step S2 can be carried out.

[0041] Next, in step S3, the surrounding ground G is frozen together with the backfill material 35 in the tail void 31, including the boundary C where the aforementioned cleaning was performed. Thus, good freezing can be achieved between the frozen soil, consisting of the surrounding ground G and backfill material 35, and the shield tunnel 10. A well-known freezing method can be used to form the frozen soil. That is, for example, a freezing pipe may be inserted from the ground or inside the shield tunnel 10 toward the surrounding ground G, and a refrigerant may be circulated through the freezing pipe to freeze the surrounding ground G and the backfill material 35. Alternatively, the surrounding ground G and backfill material 35 may be frozen by circulating a refrigerant through a freezing pipe provided in a segment S that constitutes the shield tunnel 10.

[0042] According to this embodiment, the method for freezing the ground includes, when constructing the shield tunnel 10 with the shield machine 1, filling the space between the tail brushes 21 of the shield machine 1 with a filler material (e.g., tail grease 22) and filling the tail void 31 behind the tail brushes 21 with backfill material 35 (step S1), cleaning the space between the outer surface 33 of the shield tunnel 10 and the backfill material 35 in the tail void 31 (boundary C) (step S2), and, after this cleaning is performed, freezing the ground surrounding the shield tunnel 10 (surrounding ground G) together with the backfill material 35 in the tail void 31 (step S3). Therefore, good freezing can be achieved between the frozen soil consisting of the surrounding ground G and backfill material 35 and the shield tunnel 10.

[0043] Furthermore, according to this embodiment, cleaning the aforementioned boundary C involves injecting a cleaning solution into the space between the outer surface 33 of the shield tunnel 10 and the backfill material 35 in the tail void 31 (the boundary C). The filler material (e.g., tail grease 22, 22a) contains oil and fat, and the cleaning solution contains a surfactant. Therefore, the emulsifying action of the surfactant in the cleaning solution can emulsify the tail grease 22a and increase its fluidity, thereby promoting the removal of the tail grease 22a from the boundary C.

[0044] Furthermore, according to this embodiment, the cleaning fluid is injected through a first through-hole 51 that penetrates the inside and outside of the shield tunnel 10 into the space between the outer circumferential surface 33 of the shield tunnel 10 and the backfill material 35 in the tail void 31 (boundary C). This allows the cleaning fluid to be easily injected into the boundary C from inside the shield tunnel 10.

[0045] Furthermore, according to this embodiment, the cleaning liquid (the waste liquid mentioned above) used to clean the boundary C is recovered into the shield tunnel 10 through the second through-hole 52 that penetrates the shield tunnel 10 to the inside and outside. This makes it possible to easily recover the tail grease 22a from the boundary C.

[0046] Next, a second embodiment of the present invention will be described with reference to Figures 7 to 10. Figure 7 is a flowchart showing the ground freezing method in this embodiment. Figure 8 is a diagram showing the schematic configuration of the gap-filling material filling system 60. Figures 9(a) to 10(d) show an example of the cleaning and gap-filling material filling method in this embodiment. The differences from the first embodiment described above will now be explained.

[0047] In this embodiment, in step S2' of the ground freezing method shown in Figure 7, the area between the backfill material 35 filled in the tail void 31 and the outer surface 33 of the shield tunnel 10 (boundary C) is cleaned using the cleaning system 40. Subsequently, the gap-filling material 70 (see Figures 9(a) to 10(d)) is filled into the cleaned area using the gap-filling material filling system 60.

[0048] As shown in Figure 8, the gap-filling material filling system 60 is placed in the location where the aforementioned cleaning liquid injection system 41 was removed. The gap-filling material filling system 60 is configured to inject the gap-filling material 70 into the aforementioned boundary C (which has been cleaned) from the tip 63 of the injection pipe 62 by the operation of a pressure pump 61. Here, the gap-filling material 70 may be, for example, a suspension-type settlement prevention filler used to prevent ground subsidence.

[0049] The injection pipe 62 is inserted into the first through-hole 51 from inside the shield tunnel 10 so that its tip 63 faces the aforementioned boundary C (which has been cleaned). The aforementioned pressure pump 61 is located inside the shield tunnel 10.

[0050] In step S2' of this embodiment, in the gap-filling material filling system 60, while operating the pressure pump 61, the gap-filling material 70 is injected under pressure into the aforementioned boundary C (which has been cleaned) from the tip 63 of the injection pipe 62, thereby replacing the cleaning liquid in the boundary C with the gap-filling material 70.

[0051] The waste liquid generated by this substitution is collected in the waste liquid tank 49 by operating the vacuum pump 46 of the waste liquid recovery system 42, which sucks the waste liquid from the aforementioned boundary C through the tip 48 of the discharge pipe 47. At this point, when the waste liquid collected in the waste liquid tank 49 becomes the gap-filling material 70 itself, the filling of the gap-filling material 70 is considered complete, and the operation of the gap-filling material filling system 60 and the waste liquid recovery system 42 may be stopped.

[0052] Figure 8 shows an arrangement in which the injection pipes 62 (first through-hole 51) and discharge pipes 47 (second through-hole 52) are arranged alternately and at intervals along the tunnel axis. However, the injection pipes 62 (first through-hole 51) and discharge pipes 47 (second through-hole 52) may also be arranged alternately and at intervals along the tunnel circumferential direction. Furthermore, in the unfolded view of the shield tunnel 10, the injection pipes 62 (first through-hole 51) and discharge pipes 47 (second through-hole 52) may be arranged alternately and at intervals in a matrix or staggered pattern. In any case, the injection pipes 62 (first through-hole 51) and discharge pipes 47 (second through-hole 52) can be appropriately arranged so that the waste liquid generated by the operation of the gap-filling material filling system 60 can be efficiently recovered by the waste liquid recovery system 42.

[0053] In this embodiment, for cleaning with a cleaning solution and filling with gap-filling material 70 in step S2', it is preferable to divide the tunnel circumferentially into several regions and proceed with cleaning sequentially from the lower region (high-pressure side region) to the upper region (low-pressure side region). In this regard, Figures 9(a) to 10(d) show an example of this cleaning and gap-filling method.

[0054] First, as shown in Figures 9(a) and (b), the region A1 at the boundary C is cleaned by cleaning with the cleaning system 40 using the first through-hole 51a at the lowest end. Following this cleaning, the region A1 is filled with gap-filling material 70 by the gap-filling material filling system 60.

[0055] Next, as shown in Figure 10(c), the areas A2 and A3 at the aforementioned boundary C are cleaned by cleaning using the cleaning system 40, which utilizes the first through-hole 51b in the lower left and the first through-hole 51c in the lower right. Following this cleaning, the gap-filling material 70 is filled into the areas A2 and A3 using the gap-filling material filling system 60.

[0056] Next, as shown in Figure 10(E), the area A4 at the aforementioned boundary C is cleaned by cleaning with the cleaning system 40, using the first through-hole 51d in the upper left, the first through-hole 51e in the upper right, and the first through-hole 51f at the top end. Following this cleaning, the area A4 is filled with gap-filling material 70 by the gap-filling material filling system 60.

[0057] As described above, the cleaning with the cleaning solution and filling of the gap-filling material 70 in step S2' of this embodiment can be carried out.

[0058] In step S3 of this embodiment, the surrounding ground G is frozen together with the backfill material 35 in the tail void 31, including the boundary C where the cleaning with the aforementioned cleaning solution and filling with the gap-filling material 70 have been carried out. Preferably, the gap-filling material 70 is composed of components that promote the freezing of the frozen soil, consisting of the surrounding ground G and backfill material 35, with the shield tunnel 10 (in other words, components that do not inhibit such freezing).

[0059] In particular, according to this embodiment, the method for freezing the ground includes cleaning the boundary C between the outer surface 33 of the shield tunnel 10 and the backfill material 35 in the tail void 31, and then filling the boundary C with gap-filling material 70 (step S2'). This makes it possible to efficiently implement measures to prevent ground subsidence immediately following the cleaning.

[0060] Next, a third embodiment of the present invention will be described with reference to Figure 11. Figure 11 is a flowchart showing the ground freezing method in this embodiment. The differences from the first embodiment described above will now be explained.

[0061] In this embodiment, the order of steps S2 and S3 described above is reversed compared to the first embodiment. That is, in this embodiment, prior to cleaning the boundary C between the outer surface 33 of the shield tunnel 10 and the backfill material 35 in the tail void 31, the surrounding ground G is frozen together with the backfill material 35 in the tail void 31. Furthermore, the boundary C is cleaned in at least this frozen area.

[0062] In particular, according to this embodiment, the method for freezing the ground includes filling the space between the tail brushes 21 of the shield machine 1 and filling the tail void 31 behind the tail brushes 21 with backfill material 35 when constructing the shield tunnel 10 with the shield machine 1 (step S1), cleaning the space between the outer surface 33 of the shield tunnel 10 and the backfill material 35 in the tail void 31 (boundary C) (step S2), and prior to this cleaning, freezing the ground surrounding the shield tunnel 10 (surrounding ground G) together with the backfill material 35 in the tail void 31 (step S3). Even in this frozen state, the cleaning liquid can flow through the boundary C, so cleaning with the cleaning liquid can be achieved.

[0063] Next, a fourth embodiment of the present invention will be described with reference to Figure 12. Figure 12 is a flowchart showing the ground freezing method in this embodiment. The differences from the second embodiment described above will now be explained.

[0064] In this embodiment, the order of steps S2' and S3 described above is reversed compared to the second embodiment described above. That is, in this embodiment, prior to cleaning the boundary C between the outer surface 33 of the shield tunnel 10 and the backfill material 35 in the tail void 31 and filling the gap-filling material 70, the surrounding ground G is frozen together with the backfill material 35 in the tail void 31. Furthermore, the cleaning of the boundary C and filling of the gap-filling material 70 are performed in at least this frozen area.

[0065] In particular, according to this embodiment, the method for freezing the ground includes filling the space between the tail brushes 21 of the shield machine 1 and filling the tail void 31 behind the tail brushes 21 with backfill material 35 when constructing the shield tunnel 10 with the shield machine 1 (step S1), cleaning the space between the outer surface 33 of the shield tunnel 10 and the backfill material 35 in the tail void 31 (boundary C), and after this cleaning, filling the boundary C with gap-filling material 70 (step S2'), and prior to this cleaning and filling of gap-filling material 70, freezing the ground surrounding the shield tunnel 10 (surrounding ground G) together with the backfill material 35 in the tail void 31 (step S3). Even in this frozen state, the cleaning liquid can flow through the boundary C, so cleaning with the cleaning liquid can be achieved. Also, even in this frozen state, the gap-filling material 70 can flow through the boundary C, so filling with the gap-filling material 70 can be achieved.

[0066] The illustrated embodiments are merely illustrative of the present invention, and it goes without saying that the present invention includes not only those directly shown by the described embodiments, but also various improvements and modifications made by those skilled in the art within the scope of the claims. [Explanation of Symbols]

[0067] 1...Shield machine, 2...Skin plate, 2a...Tail section, 3...Cutter head, 4...Shield bulkhead, 5...Drive motor, 6...Cutter chamber, 7...Screw conveyor, 8...Erector device, 9...Gripping section, 10...Shield tunnel, 11...Propulsion jack, 12...Cylinder, 13...Rod, 21...Tail brush, 22,22a...Tail grease, 23...Tail seal section, 31...Tail void, 32...Excavation surface, 33...Outer surface, 35...Backfill material, 40...Cleaning System, 41...Cleaning fluid injection system, 42...Waste liquid recovery system, 43...High-pressure sprayer, 44...Injection pipe, 45...Injection nozzle, 46...Vacuum pump, 47...Discharge pipe, 48...Tip section, 49...Waste liquid tank, 51, 51a~51f...First through hole, 52...Second through hole, 60...Gap filling material filling system, 61...Pressure pump, 62...Injection pipe, 63...Tip section, 70...Gap filling material, A1~A4...Area, C...Boundary, G...Surrounding ground, S...Segment, SR...Segment ring

Claims

1. When constructing a shield tunnel with a shield machine, filler material is filled between the tail brushes of the shield machine, and backfill material is filled into the tail void behind the tail brushes. At a minimum, the area between the outer surface of the shield tunnel and the backfill material in the tail void shall be cleaned, and After the cleaning is performed, the ground surrounding the shield tunnel is frozen together with the backfill material in the tail void. Includes, The cleaning process includes injecting a cleaning solution containing a surfactant between the outer surface of the shield tunnel and the backfill material in the tail void. Methods for freezing the ground.

2. When constructing a shield tunnel with a shield machine, filler material is filled between the tail brushes of the shield machine, and backfill material is filled into the tail void behind the tail brushes. At a minimum, the area between the outer surface of the shield tunnel and the backfill material in the tail void shall be cleaned, and Prior to the aforementioned cleaning, the ground surrounding the shield tunnel is frozen together with the backfill material in the tail void. Includes, The cleaning process includes injecting a cleaning solution containing a surfactant between the outer surface of the shield tunnel and the backfill material in the tail void. Methods for freezing the ground.

3. The method for freezing ground according to claim 1 or claim 2, wherein the filler material contains oil or fat.

4. The method for freezing ground according to claim 1 or 2, wherein the cleaning liquid is injected between the outer surface of the shield tunnel and the backfill material in the tail void through a first through-hole that penetrates the shield tunnel to the inside and outside.

5. The method for freezing ground according to claim 4, wherein the cleaning liquid used for the cleaning is recovered into the shield tunnel through a second through-hole that penetrates the shield tunnel to the inside and outside.

6. The method for freezing ground according to claim 1 or claim 2, further comprising filling the space between the outer surface of the shield tunnel and the backfill material in the tail void after the cleaning has been performed.

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