Construction equipment and construction method for observation holes for checking linear accuracy in tunnel excavation

Abstract

To ensure watertightness at the connection between the penetration pipe and the tunnel lining during the construction of a penetration pipe used as an observation hole for checking linear accuracy, to prevent water leakage for a long period at the connection between the penetration pipe and the tunnel lining during the installation of the observation hole for checking linear accuracy and after it is closed, to shorten the construction period of the observation hole for checking linear accuracy, and to minimize the construction load associated with the watertight construction. [Solution] The system comprises a drilling device that drills, from above ground, a through hole to be used as an observation hole in the tunnel lining installed inside the tunnel being excavated, a through pipe that is inserted into the through hole from above ground, a side wall member that covers the area around the position where the through pipe penetrates the tunnel lining on the air side of the tunnel being drilled, a blocking cover that is installed on the open face of the side wall member at the position where the through pipe penetrates the tunnel lining to form a blocking box, and a freezing pipe that is inserted into the through pipe to create frozen soil around the connection between the tunnel lining and the through pipe.

Description

[Technical Field]

[0001] The present invention relates to a construction device for an observation hole for confirming linear accuracy in tunnel excavation and a construction method using the construction device, for example, a construction device for an observation hole for confirming linear accuracy in a shield tunnel constructed at great depth and a construction method using the construction device. [Background technology]

[0002] When excavating a long-distance tunnel, it is necessary to ensure alignment accuracy by aligning the surveying standards between the surface and the tunnel shaft along the route. For this reason, an observation hole for checking alignment accuracy (a small vertical hole connecting the surface and the tunnel shaft) is installed from the surface to the tunnel shaft along the route. When installing an observation hole for checking alignment accuracy, the tunnel lining is penetrated underground (below the groundwater level), so highly reliable watertight measures are essential, especially when the groundwater pressure is high. Various technologies have been proposed for watertight measures when installing an observation hole for checking alignment accuracy (see, for example, Patent Document 1).

[0003] The technology described in Patent Document 1 relates to RC segments that are intended to enable check boring and core boring in shield tunnels using RC segments without causing water intrusion or leakage.

[0004] This RC segment is equipped with a steel pipe with an observation hole that communicates with a check borehole casing (third casing) buried to connect the inside and outside of the RC segment. It also includes an injection fitting with an injection hole detachably installed in the observation hole of the steel pipe, an injection fitting plug detachably installed in the injection hole of the injection fitting, and reinforcing steel bars arranged around the steel pipe. The tip of the casing that penetrates from the ground is inserted into the outer surface of the RC segment, and injection material is injected into the bottom end of the casing. After that, a hole is drilled from inside the tunnel tunnel for the observation hole, connecting the observation hole to the casing, and then measurement is performed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2006-57277 A (Patent No. 4448405 A) Summary of the Invention [Problem to be solved by the invention]

[0006] Conventional water-stopping methods for installing observation holes for checking linear accuracy, including the technology described in Patent Document 1, can be broadly divided into chemical injection and freezing methods. These conventional methods have various issues that need to be resolved, such as poor water-stopping effectiveness, a high risk of water leakage, and long construction times.

[0007] In particular, shield tunnel construction, which involves construction conditions of great depth and high water pressure, poses the following challenges. First, due to the great depth and high water pressure, it is necessary to ensure watertightness (ensuring safety during construction) when installing observation holes for linear accuracy confirmation (when penetrating the lining). To achieve this, it is necessary to create an improved structure with reliable watertightness and eliminate the risk of water leakage when penetrating the lining. Second, after the installation and closing of the observation holes for linear accuracy confirmation, it is necessary to prevent water leakage from the lining penetration points under high water pressure for a long period of time (e.g., a service life of approximately 100 years). Third, if the construction period needs to be shortened, the installation period of the observation holes for linear accuracy confirmation must also be shortened. Fourth, from the perspective of streamlining the tunnel lining structure and ensuring long-term quality, it is necessary to minimize the load during construction associated with watertight construction.

[0008] The present invention has been proposed in consideration of the above-mentioned circumstances, and aims to provide a construction device and construction method for an observation hole for confirming linear accuracy in tunnel excavation, which ensures watertightness at the connection between the penetration pipe and the tunnel lining when constructing the penetration pipe used as an observation hole for confirming linear accuracy, prevents water leakage at the connection between the penetration pipe and the tunnel lining for a long period of time when the observation hole for confirming linear accuracy is installed and after it is closed, shortens the construction period of the observation hole for confirming linear accuracy, and minimizes the construction load associated with watertight construction. [Means for solving the problem]

[0009] The construction device and construction method for observation holes for checking linear accuracy in tunnel excavation according to the present invention have been proposed in view of the above-mentioned circumstances, and have the following features: The construction device and construction method for observation holes for checking linear accuracy in tunnel excavation according to the present invention are devices and methods that are particularly suitable for use in the construction of shield tunnels at great depths and with high water pressure.

[0010] The construction device for observation holes for confirming linear accuracy in tunnel excavation according to the present invention is a device for constructing observation holes for confirming linear accuracy in tunnel excavation, and is equipped with a drilling device that drills a through hole to be used as an observation hole from above ground in a tunnel lining installed inside the tunnel being excavated, a penetration pipe that is inserted into the through hole from above ground, a side wall member that is a component of a blocking box that covers the area around the penetration position of the penetration pipe on the air surface side of the tunnel during drilling, a blocking cover that is installed on the open surface of the side wall member that constitutes the blocking box and blocks the side wall member to form the blocking box, and a freezing pipe that is inserted into the penetration pipe to create frozen soil around the connection between the tunnel lining and the penetration pipe.

[0011] In the construction device for the observation hole for confirming linear accuracy in the above-mentioned tunnel excavation, it is possible to configure it to be equipped with, in addition to the freezing pipe, an adhesive freezing pipe that is attached to the inner surface of the tunnel lining, around the connection between the tunnel lining and the penetration pipe.

[0012] In the construction device for the observation hole for confirming linear accuracy in the above-mentioned tunnel excavation, in order to install the freezing pipe after connecting the penetration pipe to the tunnel lining, it is possible to configure the device to include at least a freezing pipe insertion guide tube that is installed in the blocking cover, a packer attached to the end of the freezing pipe insertion guide tube on the inner surface side of the tunnel lining, a freezing pipe installation device, and its accessory parts.

[0013] The construction device for the observation hole for checking linear accuracy in the tunnel excavation described above can be configured to include heat insulating material installed around the closure box and on the inner surface of the tunnel lining.

[0014] The method for constructing an observation hole for confirming linear accuracy in tunnel excavation according to the present invention is a method for constructing an observation hole for confirming linear accuracy in tunnel excavation, and includes the steps of filling a filler material via a penetration pipe into a block box provided on the interior surface side of a tunnel lining installed in the tunnel being excavated, at a position where the tip of the penetration pipe, which has been inserted into the ground from above ground toward the tunnel lining, penetrates the tunnel lining; inserting a freezing pipe into the penetration pipe installed in the block box; filling a filler material into the penetration pipe with the frozen pipe inserted into it and using the frozen pipe to create frozen soil around the connection between the tunnel lining and the penetration pipe; opening the interior surface side of the block box to remove the filler material filled in the block box and welding the connection between the tunnel lining and the penetration pipe; and removing the freezing pipe from the penetration pipe and the block box. [Effects of the Invention]

[0015] The construction device and construction method for observation holes for confirming linear accuracy in tunnel excavation according to the present invention are designed to connect the tunnel lining and the penetration pipe while reliably preventing water leakage by performing a freezing treatment of the ground at the connection between the tunnel lining and the penetration pipe when connecting the tunnel lining and the penetration pipe.

[0016] Therefore, according to the construction device and construction method for observation holes for confirming linear accuracy in tunnel excavation of the present invention, it is possible to ensure watertightness at the connection point between the penetration pipe and the tunnel lining when constructing the penetration pipe to be used as an observation hole for confirming linear accuracy, prevent water leakage at the connection point between the penetration pipe and the tunnel lining for a long period of time when the observation hole for confirming linear accuracy is installed and after it is closed, shorten the construction period for constructing the observation hole for confirming linear accuracy, and minimize the construction load associated with watertight construction. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is an explanatory diagram (1) of a method for constructing an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention. [Figure 2] FIG. 2 is an explanatory diagram (2) of a method for constructing an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention. [Figure 3] FIG. 3 is an explanatory diagram (3) of a method for constructing an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention. [Figure 4] FIG. 4 is an explanatory diagram (4) of a method for constructing an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention. [Figure 5] An explanatory diagram (5) of a method for constructing an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention. [Figure 6] An explanatory diagram (6) of a method for constructing an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention. [Figure 7] An explanatory diagram (7) of a method for constructing an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention. [Figure 8] An explanatory diagram (8) of a method for constructing an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention. [Figure 9] An explanatory diagram (9) of a method for constructing an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention. [Figure 10] An explanatory diagram (10) of a method for constructing an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention. [Figure 11] An explanatory diagram (11) of a method for constructing an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention. [Figure 12] An explanatory diagram (12) of a method for constructing an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention. [Figure 13] An explanatory diagram (13) of a method for constructing an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention. [Figure 14] An explanatory diagram (14) of a method for constructing an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention. [Figure 15] An explanatory diagram (15) of a method for constructing an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention. [Figure 16] An explanatory diagram (16) of a method for constructing an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention. [Figure 17] An explanatory diagram (17) of a method for constructing an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention. [Figure 18] An explanatory diagram (18) of a method for constructing an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention. [Figure 19] FIG. 2 is an explanatory diagram of a steel segment used in an embodiment of the present invention. [Figure 20] FIG. 1 is an explanatory diagram comparing the effects of a construction method for an observation hole for checking linear accuracy in tunnel excavation according to an embodiment of the present invention with those of the prior art. DETAILED DESCRIPTION OF THE INVENTION

[0018] Below, with reference to the drawings, we will explain the construction device and construction method for observation holes for confirming linear accuracy in tunnel excavation (hereinafter sometimes abbreviated as construction device for observation holes for confirming linear accuracy and construction method for observation holes for confirming linear accuracy) according to an embodiment of the present invention.

[0019] Figures 1 to 19 explain the construction method of an observation hole for checking linear accuracy according to an embodiment of the present invention and the construction equipment used for this, with Figures 1 to 18 being cross-sectional schematic diagrams of a shield segment showing the construction method of an observation hole for checking linear accuracy in sequence, and Figure 19 being an explanatory diagram of a steel segment used in an embodiment of the present invention. Also, Figure 20 is an explanatory diagram comparing the effects of the construction method of an observation hole for checking linear accuracy according to an embodiment of the present invention with those of the prior art.

[0020] <Features of the construction method for observation holes to confirm linear accuracy> The construction method of an observation hole for checking linear accuracy according to an embodiment of the present invention is particularly suitable for use in checking linear accuracy in shield tunnels constructed at great depths. This construction method of an observation hole for checking linear accuracy includes, as its main steps, a step of drilling a through hole in the tunnel lining (hole drilling step), a step of inserting a through pipe into the through hole (through pipe installation step), a step of installing a side wall member, which is a component of a blocking box, so as to cover the periphery of the penetration position of the through pipe (side wall member installation step), a step of attaching a construction member to the blocking cover that will be required after connecting the through pipe (construction member installation step), a step of attaching a blocking cover to the open surface of the side wall member to close the blocking box (block box closing step), and a step of installing a closed blocking box. The process includes a process of filling the box with filler (block box filling process), a process of penetrating the tunnel lining and installing the tip of the penetration pipe inside the block box (penetration pipe installation process), a process of inserting a freezing pipe into the penetration pipe (freezing pipe insertion process), a process of filling the penetration pipe with filler (filler filling process), a process of creating frozen soil around the connection between the tunnel lining and the penetration pipe (frozen soil creation process), a process of welding the connection between the tunnel lining and the penetration pipe (welding process), and a process of removing the frozen pipe from the penetration pipe and the block box (frozen pipe removal process).

[0021] Furthermore, additional processes to each of the above-mentioned processes can include a process of identifying the penetration position of the penetration pipe relative to the tunnel lining (penetration position identification process), a process of removing a component of the tunnel lining if that component interferes with the penetration position of the penetration pipe (interfering component removal process), a process of marking the penetration position of the penetration pipe on a blocking lid, which is a component of the blocking box (blocking lid marking process), a process of removing the filler material filled in the penetration pipe (filler removal process), a process of installing an adhesive freezing tube on the inner surface of the tunnel lining around the penetration pipe (adhesive freezing tube installation process), a process of installing heat insulation material around the blocking box and on the inner surface of the tunnel lining (heat insulation installation process), and a process of using the penetration pipe as an observation hole for confirming linear accuracy, and then closing the side wall member that constitutes the blocking box with a permanent blocking lid and filling the penetration pipe and the blocking box with filler, thereby closing the observation hole for confirming linear accuracy (linear accuracy confirmation observation hole closing process).

[0022] Each step will be described in detail below with reference to the drawings. The construction equipment used in each step will also be explained. The following example shows the application of the present invention to a shield tunnel using steel segments, but the present invention can also be applied to other types of tunnels using a similar lining.

[0023] <Drilling process> As shown in FIG. 1, the drilling process is a process of drilling through holes from above ground into the tunnel lining (skin plate 10) being excavated. Conventionally known techniques can be applied to the process of drilling through holes. In this embodiment, a boring machine is used to drill for installing a guide pipe 20, and a penetration pipe 30 is inserted into the guide pipe 20. That is, in this embodiment, the inside of the penetration pipe 30 becomes the through hole. Note that the guide pipe 20 is installed in advance up to the vicinity of the outer circumferential surface of the tunnel lining (skin plate 10).

[0024] <Penetration pipe construction process> 1 and 2, the penetration pipe installation process is a process in which a penetration pipe 30 is inserted into a guide pipe 20. A boring bit is provided at the tip of the penetration pipe 30, and by rotating the penetration pipe 30 and advancing downward, the penetration pipe 30 protruding downward from the guide pipe 20 drills a hole, penetrates the tunnel lining (skin plate 10), and installs the penetration pipe 30 on the empty surface side of the tunnel interior.

[0025] <Penetration position identification process> As shown in Figure 2, the penetration position identification process is a process in which drilling is temporarily stopped when the tip of the penetration pipe 30 abuts against the tunnel lining (skin plate 10), and the penetration position of the penetration pipe 30 relative to the tunnel lining (skin plate 10) is identified by rotating the penetration pipe 30 while the tip of the penetration pipe 30 is abutting against the tunnel lining (skin plate 10).

[0026] When the penetration pipe 30 is rotated and pushed downward, the tip of the penetration pipe 30 comes into contact with the outer peripheral surface of the skin plate 10. If the penetration pipe 30 is then pushed downward while being rotated, the penetration pipe 30 will penetrate into the tunnel interior surface, which is not yet cured. Therefore, when the penetration pipe 30 penetrates the skin plate 10, a blocking box 40 must be installed on the tunnel interior surface side. As will be described in detail later, the side wall member 41 constituting the blocking box 40 in this embodiment is a member formed from the main girders and longitudinal ribs of the steel segments when the tunnel lining (steel segments) is manufactured. Therefore, when the penetration pipe 30 penetrates the skin plate 10, the side wall member 41 is already installed.

[0027] When the tip of the penetration pipe 30 is kept in contact with the outer peripheral surface of the skin plate 10 and rotation is maintained, the contact point of the penetration pipe 30 on the skin plate 10 becomes hot. Therefore, by obtaining heat distribution data around the contact point of the penetration pipe 30 from the tunnel interior surface using thermography or the like, the penetration position of the penetration pipe 30 in the skin plate 10 can be identified.

[0028] <Interfering component removal process> In the above-mentioned penetration position specifying step, when the penetration position of the skin plate 10 by the penetration pipe 30 is specified, there may be a case where a reinforcing rib 50, which is a component of the tunnel lining, is present at the penetration position, as shown in Fig. 2. In this case, if the penetration work of the penetration pipe 30 is continued through the skin plate 10, the reinforcing rib 50, etc. will interfere with the penetration pipe 30, causing an obstacle to the installation of the penetration pipe 30.

[0029] 3, in this embodiment, when the penetration position of the penetration pipe 30 relative to the tunnel lining (skin plate 10) is identified, if a component of the tunnel lining (reinforcing rib 50, etc.) interferes with the penetration position of the penetration pipe 30, a process of removing the component of the tunnel lining (reinforcing rib 50, etc.) is carried out. To remove the reinforcing rib 50, etc., it is sufficient to cut the reinforcing rib 50, etc. from the tunnel interior surface side.

[0030] <Side wall component installation process> 4 and 5, the side wall member installation process is a process of installing a side wall member 41, which is a component of a blocking box 40, on the tunnel interior surface side so as to cover the periphery of the penetration position of the penetration pipe 30. The blocking box 40 is a member for blocking the periphery of the penetration position of the penetration pipe 30, and includes a side wall member 41 attached to the skin plate 10, and a blocking lid 42 for closing the open surface (opening) of the side wall member 41 located on the tunnel interior surface side.

[0031] In this embodiment, steel segments are used, and as shown in FIGS. 19(a) and 19(b), when the steel segments are manufactured, sidewall members 41 are created using the main girders 12 and longitudinal ribs 13 of the steel segments. Therefore, when the tunnel lining (steel segments) is installed, the sidewall members 41 that surround the penetration position of the penetration pipe 30 are installed. In addition, a blocking cover base 43 for attaching a blocking cover 42 is provided on the sidewall member 41. Then, the blocking cover 42 is attached to the open surface of the sidewall member 41 (the opening on the tunnel interior surface side), forming a blocking box 40, which can block the periphery of the penetration position of the penetration pipe 30. The blocking cover 42 can be attached to the blocking cover base 43 provided on the open surface of the sidewall member 41 by, for example, bolting.

[0032] The sidewall member 41 in this embodiment will be described in more detail with reference to Figure 19. Figure 19(a) is a cross-sectional view of a steel segment, and Figure 19(b) is a plan view of the steel segment. As shown in Figures 19(a) and 19(b), the sidewall member 41 is a rectangular tubular member whose sidewall portion is formed by the main girders 12 and longitudinal ribs 13. The longitudinal ribs 13 include longitudinal rib webs 13a protruding from the skin plate 10 and longitudinal rib flanges 13b provided at the tips of the longitudinal rib webs 13a. In addition, a block cover base 43 is attached to the inside of each opposing main girder 12 so that it is flush with the vertical rib flanges 13b.

[0033] The vertical rib flange 13b and the block lid base 43 each have a plurality of bolt holes (not numbered). Therefore, the block lid 42 can be bolted to the underside of the side wall member 41 formed by the main girder 12 and the vertical rib web 13a to form the block box 40. In this embodiment, the shaded area in Figure 19(b) is the area that becomes the block box 40.

[0034] It should be noted that instead of creating the side wall member 41 using the main girders 12 and vertical ribs 13 of the steel segments, the side wall member 41 may be attached to the tunnel lining after the penetration position of the penetration pipe 30 has been identified. In this case, the side wall member 41 is attached to the skin plate 10, and a blocking lid 42 is attached to the open face of the side wall member 41 (the opening on the tunnel interior surface side), thereby forming a blocking box 40, which can block the area around the penetration position of the penetration pipe 30.

[0035] <Closure lid marking process> As shown in FIG. 4 , the block lid marking process is a process for marking the identified penetration position of the penetration pipe 30 on the block lid 42 installed on the tunnel interior surface side of the block box 40. The penetration position of the penetration pipe 30 relative to the tunnel lining (skin plate 10) can be identified by the above-described penetration position identification process. Furthermore, the position where the block lid 42 is attached to the side wall member 41 constituting the block box 40 is known in advance. Therefore, when the block lid 42 is attached to the side wall member 41, a position facing the penetration position of the penetration pipe 30 relative to the tunnel lining (skin plate 10) is marked on the block lid 42. This allows preparations to be made for attaching a construction member to the insertion position of the freezing pipe 60 in the subsequent freezing pipe insertion process. To mark the penetration position of the penetration pipe 30, for example, the block lid 42 may be marked with paint or other paint.

[0036] <Installation process for construction components> As shown in FIG. 5, the construction member attachment process is a process of attaching construction members required after connecting the penetration pipe 30 to the tunnel lining to the positions marked on the blocking cover 42. The construction members required after connecting the penetration pipe 30 to the tunnel lining include at least a freezing pipe insertion guide pipe 71 for inserting the freezing pipe 60 into the penetration pipe 30, a packer 72, and an installation device for the freezing pipe 60 (e.g., a boring machine 73) and its associated components. The associated components include an injection pipe 74 and an air vent pipe 75 for filling the filler material, and an opening / closing member 76 and an opening / closing operating member 77 for opening and closing the freezing pipe insertion guide pipe 71. By attaching the construction members and their associated components to the blocking cover 42, subsequent processes such as the blocking box filling process and the freezing pipe insertion process can be performed.

[0037] <Occupation box closure process> As shown in FIGS. 5 to 9 , the blocking box blocking step is a step of placing a blocking lid 42 on the open surface of the sidewall member 41 (the opening on the tunnel interior surface side) to block the blocking box 40. The blocking box 40 is composed of the sidewall member 41 attached to the skin plate 10 and the blocking lid 42 attached to the open surface of the sidewall member 41 (the opening on the tunnel interior surface side). The sidewall member 41 is attached so as to surround the penetration position of the through-pipe 30 in the skin plate 10, and the blocking lid 42 is attached to the open surface of the sidewall member 41 (the opening on the tunnel interior surface side). By attaching the sidewall member 41 to the skin plate 10 so as to surround the penetration position of the through-pipe 30, and attaching the blocking lid 42 to the open surface of the sidewall member 41 (the opening on the tunnel interior surface side), a closed space can be formed surrounding the penetration position when the through-pipe 30 is attached through the skin plate 10. The blocking lid 42 is attached to a blocking lid base 43 provided on the sidewall member 41. Furthermore, in this embodiment, a filler 44 is filled inside the blocking lid 42. Therefore, water leakage from the penetration position of the skin plate 10 can be prevented from occurring after the penetration pipe 30 is attached by penetrating the skin plate 10 until the skin plate 10 and the penetration pipe 30 are welded together.

[0038] In the above description, the closing box closing process is carried out after the installation member attaching process. Both processes are a series of processes for attaching the installation member to the closure lid 42 and closing the closure box 40 by attaching the closure lid 42 to the opening of the side wall member 41. Therefore, in consideration of the efficiency of the work, the closing box closing process may be carried out first and then the installation member attaching process may be carried out, or both processes may be carried out in parallel.

[0039] <Closed box filling process> As shown in Fig. 6, the blocking box filling process is a process of filling a filler 44 into a blocked blocking box 40. The filler 44 is, for example, cement bentonite. To fill the blocking box 40 with the filler 44, an injection pipe 74 and an air vent pipe 75 attached to the blocking lid 42 are used. That is, the filler 44 can be filled into the blocking box 40 by pressurizing the filler 44 through the injection pipe 74 and venting air from inside the blocking box 40 through the air vent pipe 75.

[0040] <Penetration pipe installation process> 7 and 8, the penetration pipe installation process is a process in which the tip of the penetration pipe 30 penetrates the tunnel lining (skin plate 10) and installs inside the blocking box 40. When the penetration pipe 30 is in contact with the outer peripheral surface of the tunnel lining (skin plate 10), the penetration pipe 30 is pushed down toward the skin plate 10 while rotating, and the penetration pipe 30 can be installed by penetrating the skin plate 10. Then, the penetration pipe 30 is further pushed down (inserted into the tunnel interior surface), and when the tip of the penetration pipe 30 reaches near the inner surface of the blocking lid 42, the pushing down of the penetration pipe 30 (insertion into the tunnel interior surface) is stopped.

[0041] <Freezing tube insertion process> 9 and 10, the freezing pipe insertion process is a process of inserting the freezing pipe 60 into the penetration pipe 30 using construction members. The construction members used in the freezing pipe insertion process are a guide pipe (freezing pipe insertion guide pipe 71) for inserting the freezing pipe 60 into the penetration pipe 30, a packer 72, a boring machine 73, and its associated members.

[0042] To insert the freezing pipe 60 into the penetration pipe 30, the freezing pipe 60 is inserted into the penetration pipe 30 from an opening provided in the blocking lid 42 via a freezing pipe insertion guide pipe 71 and a packer 72. At this time, the freezing pipe 60 is inserted up to the position where frozen soil will be formed while the tip of the freezing pipe 60 pushes up the cored skin plate 11. A check valve 49 is installed at the tip of the water supply pipe installed together with the freezing pipe 60.

[0043] The freezing pipe 60 is a device for circulating a refrigerant to form frozen soil 100. It includes a heat exchanger and a circulation pump for cooling and circulating the refrigerant. This freezing pipe 60 can be a well-known device used in ground freezing techniques. Although not shown, in this embodiment, a double-pipe structure is used as the freezing pipe 60. Specifically, the outer pipe of the freezing pipe 60 contains a water supply pipe for transporting drilling water and an inner circulation pipe for injecting brine, a refrigerant. The brine is delivered from the refrigerator, passes through the inner circulation pipe, and is then pumped into the outer pipe before being circulated to the refrigerator. The water supply pipe is used to transport drilling water during drilling, but also functions as a filler injection pipe when filling the hole.

[0044] 13 and 14, in this embodiment, an adhesive freezing pipe 80 is attached to the inner surface of the tunnel lining (skin plate 10) and the outer periphery of the penetration pipe 30. This adhesive freezing pipe 80 is a type of freezing pipe 60, and although its shape is different from that of the freezing pipe 60, the cooling principle and device configuration are almost the same.

[0045] <Filler filling process> 11, the filler filling step is a step of filling a filler 45 into the penetration pipe 30 into which the freezing pipe 60 has been inserted. Cement bentonite, for example, can be used as the filler 45. The filler 45 is filled into the penetration pipe 30 in order to efficiently conduct heat from the freezing pipe 60 to the soil present on the outer periphery of the penetration pipe 30, and to prevent water leakage at the penetration portion of the penetration pipe 30 until welding of the skin plate 10 and the penetration pipe 30 is completed.

[0046] <Heat insulation material installation process> As shown in Fig. 12, the heat insulation material installation process is a process of installing heat insulation material 90 around the blocked box 40 prior to the frozen soil creation process. The heat insulation material 90 can be, for example, a glass wool sheet. In the heat insulation material installation process, the glass wool sheet is installed around the blocked box 40 (on the surface of the blocked box 40 and the skin plate 10). This improves the heat insulation effect when creating frozen soil using the freezing pipes 60, making it possible to create frozen soil 100 more efficiently and quickly and slowing down the melting rate of the frozen soil 100.

[0047] <Frozen soil creation process> As shown in Figure 12, the frozen soil creation process is a process of creating frozen soil 100 around the connection between the tunnel lining (skin plate 10) and the penetration pipe 30 using a freezing pipe 60. Water-stopping methods using a freezing pipe 60 are well-known techniques, but in the present invention, the freezing pipe 60 is inserted into the penetration pipe 30 from the inner surface side of the tunnel, and frozen soil 100 is created around the penetration part of the penetration pipe 30. Therefore, compared to conventional construction methods, the present invention can achieve excellent effects that are unique to the present invention. A comparison of the effects of the conventional construction method and the present invention will be described in detail later.

[0048] <Welding process> 13 and 14, the welding process is a process in which the blocking lid 42 attached to the blocking box 40 is removed, the filler material 44 filled in the blocking box 40 is removed, and the connection part between the tunnel lining (skin plate 10) and the penetration pipe 30 is welded. In the welding process, frozen soil 100 is formed around the penetration part of the penetration pipe 30, so a high water-stopping effect can be obtained, and water leakage at the connection part between the tunnel lining (skin plate 10) and the penetration pipe 30 can be almost certainly prevented.

[0049] <Installation process of adhesive freezing pipes> 13 and 14, in this embodiment, after removing the filler material 44 packed in the blocking box 40, a freezing stick pipe 80 is installed on the inner surface side of the tunnel lining (skin plate 10) before welding the connection between the tunnel lining (skin plate 10) and the penetration pipe 30. This ensures the creation of frozen soil 100 at the penetration portion of the penetration pipe 30, and more reliably prevents water leakage at the penetration portion of the penetration pipe 30. Furthermore, in the freezing stick pipe installation process, a heat insulating material 90 is installed on the tunnel interior surface side of the freezing stick pipe 80.

[0050] <Frozen tube removal process> 15, the freezing pipe removal process is a process of removing the freezing pipe 60 from the penetration pipe 30 and the blocking box 40. In this freezing pipe removal process, the attached freezing pipe 80 is also removed. When removing the freezing pipe 60, the ancillary equipment for the freezing pipe 60 is also removed, and when removing the attached freezing pipe 80, the ancillary equipment for the attached freezing pipe 80 is also removed. In this state, the side wall member 41 with the blocking lid 42 removed remains, and the filler material 45 remains inside the penetration pipe 30.

[0051] <Filler removal process> As shown in Figure 16, the filler removal process involves cutting off the tip of the penetration pipe 30 inserted into the blocking box 40 and removing the filler 45 that has been filled in the penetration pipe 30. To remove the filler 45, the filler 45 can be scraped out using a scraping rod or the like, or washed away with high-pressure water. At this time, the cored skin plate 11 is also removed at the same time. By performing this process, an observation hole for checking linear accuracy can be formed, penetrating from the ground to the interior surface of the tunnel.

[0052] In this embodiment, the purpose is to confirm the linear accuracy of tunnel excavation using the formed observation hole for checking linear accuracy, as shown in Figure 17. Note that the observation hole for checking linear accuracy according to this embodiment can also be used to check the ground conditions (geology, ground behavior, etc.) in the same way as a general observation hole.

[0053] <Observation hole closure process for checking linear accuracy> As shown in Figure 18, the linear accuracy confirmation observation hole closing process involves using the penetration pipe 30, from which the filler 45 has been removed, as an observation hole for linear accuracy confirmation. Then, the closing box 40 is closed with a permanent closing cover 47, and the penetration pipe 30 and the closing box 40 are filled with a filler 46, thereby closing the observation hole for linear accuracy confirmation. In the linear accuracy confirmation observation hole closing process, a penetration pipe closing cover 31 is attached to the tip of the penetration pipe 30, and the filler 46 is filled from above ground. A mortar injection port 48 is provided in the permanent closing cover 47, and the filler 46 is filled into the closing box 40. For example, cement bentonite can be used as the filler 46 filled into the penetration pipe 30, and mortar can be used as the filler 46 filled into the closing box 40. By performing this linear accuracy confirmation observation hole closing process, water leakage from the lining penetration point can be prevented for a long period of time (for example, a service life of approximately 100 years) under high water pressure.

[0054] <Comparison of the construction method of the observation hole for checking linear accuracy according to the present invention with the prior art> We will compare the construction method of the observation hole for checking linear accuracy according to the present invention described above with the conventional chemical injection method, freezing method (1), and freezing method (2) as water-stopping methods at the connection between the tunnel lining (skin plate 10) and the penetration pipe 30, and explain how the construction method of the observation hole for checking linear accuracy according to the present invention has advantageous effects in all of the problems. In this explanation, the first problem described in the "Problem to be solved by the invention" section will be referred to as problem (1), the second problem as problem (2), the third problem as problem (3), and the fourth problem as problem (4).

[0055] <Method for forming observation holes for checking linear accuracy using conventional chemical grouting methods> In a conventional method for forming an observation hole for checking linear accuracy using chemical grouting, a penetration pipe is used to drill a hole from above ground to near the tunnel lining, and chemicals are then injected into the ground from the tunnel's interior surface through an injection hole in the tunnel lining. Then, drilling continues with the penetration pipe, and the penetration pipe penetrates the tunnel lining to form an observation hole for checking linear accuracy. This conventional method for forming an observation hole for checking linear accuracy using chemical grouting has the following drawbacks:

[0056] <Regarding assignment (1)> The conventional method of forming observation holes for checking linear accuracy using chemical grouting involves infiltration injection in gravel ground, which can be expected to have a certain degree of water-stopping effect, but in clay ground, it involves fracturing injection, which often leaves water paths. For this reason, the water-stopping effect of chemical grouting is generally inferior to that of freezing methods. Furthermore, when drilling lining holes after creating a chemical grouting improvement body, the casing is rotated, which increases the possibility of new water paths being created and increases the risk of water leaking from the existing water paths.

[0057] <Regarding assignment (2)> The conventional method of forming observation holes for checking linear accuracy using chemical grouting requires the construction of chemical grouting improvement bodies measuring several meters in length, width, and height to form a watertight zone, and more than 20 grouting holes (penetration holes) are required to stop water from entering the observation holes for checking linear accuracy. This leaves more than 20 penetration holes in the tunnel lining, which increases the risk of water leakage from these holes in the future. Furthermore, if there is water leakage when welding the outer periphery of the penetration pipe to the lining penetration, sufficient watertight welding cannot be performed, increasing the risk of water leakage from the penetration pipe penetration in the future.

[0058] <Regarding assignment (3)> As mentioned above, the conventional method of forming observation holes for checking linear accuracy using chemical grouting requires the creation of chemical grouting improvement bodies several meters in length, width, and height to form a watertight zone, and more than 20 grouting holes (through holes) are required to perform watertight construction for the installation of the observation holes for checking linear accuracy.As a result, more than 20 grouting holes (through holes) are required for the tunnel lining, and the construction cycle of installing and replacing boring machines, drilling, and grouting is required at each location, which means that watertight construction takes a long time.

[0059] <Regarding assignment (4)> The conventional method of forming observation holes for checking linear accuracy using chemical grouting requires the application of high injection pressure (for example, water pressure +0.3 Pa or more) to the area of ​​the improved structure being constructed, necessitating the application of this injection pressure as a design load, and therefore requires a highly rigid and strong tunnel lining. Furthermore, there is a risk that the chemical solution will seep into unexpected locations via water paths in the ground, adversely affecting the tunnel lining for which the injection pressure has not been taken into consideration. Furthermore, because it is uncertain which parts of the tunnel lining will be subjected to which amount of injection pressure, there is a high risk of damage to the tunnel lining due to the load during construction.

[0060] <Method of forming observation holes for checking linear accuracy using conventional freezing method (1)> In the conventional method of forming an observation hole for checking linear accuracy using freezing method (1), a penetration pipe is used to drill a hole from above ground to near the tunnel lining, a vertical freezing pipe is inserted into the ground from the tunnel surface side through an insertion hole in the tunnel lining, and an adhesive freezing pipe is installed on the inner surface of the tunnel lining, and frozen soil is formed around the penetration point of the penetration pipe by performing a freezing operation.The method then continues drilling with the penetration pipe, and penetrates the penetration pipe into the tunnel lining to form an observation hole for checking linear accuracy.This conventional method of forming an observation hole for checking linear accuracy using freezing method (1) has the following disadvantages.

[0061] <Regarding assignment (1)> The conventional freezing method (1) for forming observation holes for checking linear accuracy involves installing multiple vertical freezing pipes around the through-hole and freezing the area from the tunnel surface side using attached freezing pipes, which allows for the formation of a highly reliable water-stop zone (frozen soil). However, when drilling the lining after creating the frozen soil, the casing is rotated, which increases the possibility of new water paths being created, and there is a high risk of water leaking from these water paths.

[0062] <Regarding assignment (2)> The conventional freezing method (1) for forming observation holes for checking linear accuracy requires the installation of multiple (approximately 5 to 10) vertical freezing pipes that penetrate the tunnel lining to form a watertight zone. This leaves multiple penetration holes in the tunnel lining, increasing the risk of water leakage from the penetration holes in the future. Furthermore, if there is water leakage when welding the outer periphery of the penetration pipe to the lining penetration, sufficient watertight welding cannot be performed, increasing the risk of water leakage from the lining penetration in the future.

[0063] <Regarding assignment (3)> The conventional freezing method (1) for forming observation holes for checking linear accuracy requires the installation of multiple vertical freezing pipes, which requires a construction cycle of installing a boring machine at each location, replacing the pipes, drilling holes, and injecting water. Furthermore, it takes time to create a certain amount of frozen soil, which means that the water-stopping construction takes a long time.

[0064] <Regarding assignment (4)> The conventional freezing method (1) for forming observation holes for checking linear accuracy requires a high-rigidity and high-strength tunnel lining that takes into account the load during construction, since the freezing expansion pressure of the ground acts on the area of ​​the improvement body being constructed.

[0065] <Method of forming observation holes for checking linear accuracy using conventional freezing method (2)> In the conventional method of forming an observation hole for checking linear accuracy using freezing method (2), a penetration pipe is used to drill a hole from above ground to near the tunnel lining, a affixed freezing pipe is installed on the inner surface of the tunnel lining, and freezing operation is initiated to form frozen soil around the penetration point of the penetration pipe.The method then continues drilling with the penetration pipe, penetrating the penetration pipe into the tunnel lining to form an observation hole for checking linear accuracy.This conventional method of forming an observation hole for checking linear accuracy using freezing method (2) has the following drawbacks.

[0066] <Regarding assignment (1)> The conventional freezing method (2) for forming observation holes for checking linear accuracy involves forming a watertight zone in the ground using only a frozen pipe attached to the tunnel lining. Therefore, a certain degree of watertightness can be expected, but the watertightness is inferior to that of conventional freezing method (1) because the thickness of the frozen improvement body in the vertical direction is small. Furthermore, when drilling holes in the lining after the frozen soil has been created, the casing is rotated, which increases the possibility of new water paths being created, and there is a high risk of water leaking from these water paths.

[0067] <Regarding assignment (2)> The conventional freezing method (2) for forming observation holes for checking linear accuracy does not require any penetrations in the tunnel lining other than the observation holes for checking linear accuracy, so there is no risk of future water leakage from these. However, if there is water leakage when welding the outer periphery of the penetration pipe to the lining penetration, sufficient watertight welding cannot be performed, and the risk of water leakage from the lining penetration in the future increases.

[0068] <Regarding assignment (3)> The conventional freezing method (2) for forming observation holes for checking linear accuracy involves creating frozen soil using only attached freezing pipes, so the construction period is short.

[0069] <Regarding assignment (4)> In the conventional freezing method (2), the frozen soil area is small, so the impact of the freezing expansion pressure of the ground on the segments is small.

[0070] <Construction method of observation hole for checking linear accuracy according to the present invention> The method for constructing an observation hole for confirming linear accuracy according to the present invention is as described above.

[0071] <Regarding assignment (1)> The construction method for an observation hole for verifying linear accuracy according to the present invention exhibits high watertightness in the natural ground under high water pressure, ensuring safety during construction. In other words, a highly reliable freezing method is used for watertightness. Furthermore, the freezing pipe 60 is inserted directly into the penetration pipe 30 and filled with filler materials 44, 45 (cement bentonite, etc.), and frozen soil 100 is created by using the attached freezing pipe 80 in combination, so that water paths on the outer periphery of the penetration pipe 30 can be pinpointed for watertightness. This results in extremely high watertightness reliability.

[0072] Furthermore, by installing a waterstop box (blocking box 40) filled with filler materials 44, 45 (cement bentonite, etc.) on the inside of the tunnel lining, the procedures for "waterstop construction (freezing)" and "lining penetration" are reversed compared to conventional construction methods. This eliminates the need for casing rotation work after forming the waterstop zone, preventing the creation of new water paths. Also, by installing the waterstop box (blocking box 40), tunnel lining penetration work can be carried out without the risk of water leaking, at a stage before chemical injection or freezing methods are carried out.

[0073] <Regarding assignment (2)> The construction method for the observation hole for verifying linear accuracy according to the present invention does not require any penetrations of injection pipes or the like in the tunnel lining other than the observation hole for verifying linear accuracy (penetration), so there is no risk of future water leakage. Furthermore, when welding the outer periphery of the penetration pipe 30 to the lining penetration, there is no water leakage from the lining penetration, making high-quality watertight welding possible. Therefore, the risk of future water leakage from the outer periphery of the penetration pipe 30 is extremely low. Finally, a blocking box 40 consisting of a side wall member 41 and a blocking cover 42 is installed, mortar is filled into the blocking box 40, and the outer periphery of the penetration pipe 30 is welded, creating a triple watertight structure, so there is no risk of future water leakage.

[0074] <Regarding assignment (3)> The construction method of the observation hole for confirming linear accuracy according to the present invention requires only a very limited amount of frozen soil creation by inserting a freezing pipe 60 into the observation hole for confirming linear accuracy (penetration pipe 30) and installing an attached freezing pipe 80, so the time required for frozen soil creation is short.

[0075] <Regarding assignment (4)> In the construction method of the observation hole for checking linear accuracy according to the present invention, the frozen soil creation is limited to only the outer periphery of the observation hole for checking linear accuracy (penetration pipe 30), so excessive frozen soil expansion pressure does not act on the tunnel lining. This means that there is no need to upgrade the tunnel lining specifications due to the load effect during construction, resulting in a rational lining structure.

[0076] <Comparison results> The comparison results explained above are shown in Figure 20. As is clear from Figure 20, the construction method for observation holes for confirming linear accuracy according to the present invention is a rational construction method that can solve all of problems (1), (2), (3), and (4). In Figure 20, "x" indicates that no effect is obtained, "△" indicates that some effect is obtained, and "◯" indicates that a good effect is obtained. [Explanation of symbols]

[0077] 10 Skin Plate 11 Cored skin plate 12 Main digit 13a Vertical Rib Web 13b Vertical rib flange 20 Guide tube 30 Penetration pipe 31 Penetration pipe closure cover 40 Occlusion box 41 Side wall member 42 Occlusion lid 43 Occlusion lid pedestal 44, 45, 46 Filler 47 Closure lid for permanent installation 48 Mortar injection port 49 Check valve 50 Reinforcing rib 60 Cryotube 71 Freezing tube insertion guide tube 72 Packer 73 Boring Machine 74 Injection piping 75 Air vent pipe 76 Opening and closing member 77 Opening and closing operation member 80 Adhesive Freezing Tube 90 Heat insulation material 100 Frozen soil

Claims

1. A device for constructing observation holes to check the linear accuracy of tunnel excavation, a drilling device that drills a through-hole to be used as the observation hole from above ground in a tunnel lining installed in the tunnel being excavated; a penetration pipe inserted into the through hole from above ground; A side wall member that is a component of a blocking box that covers the periphery of the penetration position of the penetration pipe on the inner surface side of the tunnel during the boring; a blocking lid that is placed on an open surface of the side wall member that constitutes the blocking box and closes the side wall member to form the blocking box; a freezing pipe that is inserted into the penetration pipe to create frozen soil around a connection between the tunnel lining and the penetration pipe; A construction device for an observation hole for checking linear accuracy in tunnel excavation, comprising:

2. A sticking freezing pipe is provided together with the freezing pipe and is attached to the inner surface of the tunnel lining and the periphery of the connection portion between the tunnel lining and the penetration pipe in the penetration pipe, 2. A construction device for an observation hole for checking linear accuracy in tunnel excavation according to claim 1.

3. In order to install the freezing pipe after connecting the penetration pipe to the tunnel lining, at least a freezing pipe insertion guide pipe to be installed in the blocking cover, a packer attached to the end of the freezing pipe insertion guide pipe on the inner surface side of the tunnel lining, an installation device for the freezing pipe, and its accessory parts.

3. A construction device for an observation hole for checking linear accuracy in tunnel excavation according to claim 1 or 2.

4. A heat insulating material is provided around the block box and on the inner surface of the tunnel lining.

4. A construction device for an observation hole for checking linear accuracy in tunnel excavation according to claim 1.

5. A method for constructing an observation hole to confirm linear accuracy in tunnel excavation, comprising: a step of filling a filler material through a penetration pipe inserted into the ground from above ground toward the tunnel lining at the tunnel surface side of the tunnel lining installed in the tunnel being excavated, into a blocking box provided at a position where the tip of the penetration pipe penetrates the tunnel lining; inserting a freezing pipe into the penetration pipe installed in the blocking box; a step of filling a filler material into the penetration pipe into which the freezing pipe has been inserted, and creating frozen soil around a connection portion between the tunnel lining and the penetration pipe using the freezing pipe; a step of removing the filler filled in the block box by opening the tunnel interior surface side of the block box and welding the connection portion between the tunnel lining and the penetration pipe; removing the frozen pipe from the penetration pipe and the blocking box; A construction method for an observation hole for checking linear accuracy in tunnel excavation, comprising:

Images