Existing tunnel renewal method and renewal structure

Abstract

To provide an existing tunnel renewal method and renewal structure, which can perform renewal work under high safety without the need for large-scale earth retaining when renewing an existing RC tunnel that forms the existing tunnel.SOLUTION: An existing tunnel renewal method for renewing an existing RC tunnel 20A formed by an existing RC lining body 25 of an existing tunnel 20 includes a chipping step in which a tunnel interior side of the existing RC lining body 25 is chipped away, leaving a tunnel natural ground side and exposing a chipped surface 27 to the tunnel interior side, thereby forming a chipped space 28; a renewal segment installation step in which a plurality of steel renewal segments 30 are installed in the chipped space 28; and a backfill material filling step in which backfill material 39 is filled between the chipped surface 27 and the renewal segments 30.SELECTED DRAWING: Figure 7B

Description

[Technical Field]

[0001] The present invention relates to a method and structure for updating an existing tunnel. [Background technology]

[0002] Tunnels include steel tunnels, whose entire section is made up of steel segments (steel lining), RC tunnels, whose entire section is made up of RC (Rainforced Concrete) segments (RC lining), and tunnels that combine sections made up of steel tunnels and sections made up of RC tunnels (referred to in this specification as "heterogeneous tunnels").

[0003] In cases where all or part of the above types of tunnels are made of reinforced concrete (existing reinforced concrete) tunnels, and the existing reinforced concrete tunnel is damaged by concrete crushing or joint fractures due to various factors such as a vehicle collision or fire, restoration of the damaged areas is required. In addition, if a long time has passed since the construction of an existing RC tunnel and it has deteriorated over time, the deteriorated areas will need to be reinforced or renewed (renewed). In the following, in this specification, restoration, reinforcement, and renewal (renewal) of existing RC tunnels will be collectively referred to as "renewal," and therefore "renewal" will include all of these.

[0004] Here, Patent Document 1 proposes a method for updating an existing pipeline. This method is a method for updating an existing pipeline in which secondary lining concrete is provided on the inner peripheral surface of a primary lining segment. A secondary lining concrete crusher with a cutter head attached to the front end of a cylindrical body and a tunnel boring machine with a cylindrical body at the front end from which a cutter bit protrudes for excavating the ground around the outer periphery of the primary lining segment are used, and the cylindrical body of the secondary lining concrete crusher is advanced while supporting a thrust reaction force on the inner surface of the primary lining segment that has already been crushed and removed by the cutter head, thereby rotating the cutter head and crushing the secondary lining concrete forward. The secondary lining concrete is removed by transporting the crushed debris forward through the existing pipeline, and then a cylindrical body attached to the front end of the tunnel boring machine is placed over the rear end of the primary lining segment and the tunnel boring machine is moved forward while rotating, using a cutter bit protruding from the front end of the cylindrical body to excavate the ground around the primary lining segment, and the primary lining segment is dismantled inside the cylindrical body and transported forward through the primary lining segment, while a new pipeline is formed within the rear end of the tunnel boring machine as it continues to excavate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-188804 Summary of the Invention [Problem to be solved by the invention]

[0006] The method for updating existing pipelines described in Patent Document 1 is said to enable efficient dismantling and removal of existing pipelines, such as aging sewer pipes, in which secondary lining concrete is provided on the inner circumferential surface of the primary lining segments. However, this method of completely removing the entire existing pipeline poses issues regarding construction safety from the time the existing pipeline is removed until a new pipeline is constructed in the space left by the demolition, and this may result in the need for large-scale earth retaining measures.

[0007] The present invention aims to provide an existing tunnel renewal method and renewal structure that, when renewing an existing RC tunnel that forms an existing tunnel, eliminates the need for large-scale earth retaining and enables renewal construction to be carried out with high safety. [Means for solving the problem]

[0008] In order to achieve the above object, one aspect of the method for updating an existing tunnel according to the present invention is to: A method for updating an existing RC tunnel formed by an existing RC lining body among existing tunnels, A chipping process in which the tunnel interior side of the existing RC lining body is chipped off, leaving the tunnel natural ground side and exposing the chipped surface to the tunnel interior side to form a chipped space; A renewal segment installation process for installing a plurality of steel renewal segments in the chipping space; The method is characterized by having a backfilling material filling process in which backfilling material is filled between the chipped surface and the renewal segment.

[0009] According to this method, the existing RC lining body is chipped away on the tunnel interior side to form a chipped space, and steel renewal segments are installed in the chipped space to perform the renewal work.This leaves a portion of the ground side of the existing RC lining body remaining during the renewal work process, and the remaining area functions as a retaining wall, making it possible to carry out the renewal work with high safety, without the need for large-scale retaining walls. For example, if the existing RC lining has two levels of rebar, one on the ground side and one on the tunnel interior side, the area on the ground side where the rebar is buried can be left, and the area inside can be used as a chipped space. The depth to which the existing RC lining should be chipped to create the chipped space is determined based on various requirements, such as the area that needs to be updated and the extent to which the area that remains unchipped can be guaranteed to function as an earth retaining wall.

[0010] Here, "existing tunnels" include both tunnels in which the entire section is made of reinforced concrete and mixed tunnels that combine reinforced concrete and steel tunnels, and also tunnels in which the entire reinforced concrete tunnel is subject to renewal and tunnels in which only a portion of the reinforced concrete tunnel is subject to renewal. Furthermore, as explained below, there are two types of renewal areas in RC tunnels: an area extending from the middle of the existing RC lining to the end, i.e., the area on the tunnel entrance side, and an area partway along the axial direction of the RC tunnel (the area towards the center).In the former, renewal work is carried out in one direction, while in the latter, renewal work is carried out in two directions, from the left and right sides of the renewal area towards the center, so the specific content of the renewal work differs between the two.

[0011] Another aspect of the method for updating an existing tunnel according to the present invention is to The method further includes a protective work construction process in which protective work, such as chemical injection work or freezing work, is carried out from inside the existing RC tunnel on the ground behind the existing RC tunnel to be updated, and is characterized in that the protective work construction process is carried out prior to the chipping process.

[0012] According to this aspect, by carrying out protective work such as chemical injection work and freezing work on the ground behind the existing RC tunnel to be renovated, when the renewal area is at great depth or the groundwater level is high and the acting earth pressure water is high, the earth pressure water acting on the chipped area where a chipped space is formed can be reduced and watertightness can be improved, thereby further improving construction safety.

[0013] Another aspect of the method for updating an existing tunnel according to the present invention is to The method is characterized by further comprising a support step of installing internal supports to support the existing RC lining body from the air side inside the tunnel.

[0014] According to this aspect, by installing internal shoring that supports the existing RC lining body from the air inside the tunnel, it is possible to carry out renewal work while stably supporting the chipping area where the chipping space is formed from the air inside the tunnel. For example, if the renewal work area is divided into multiple parts and renewal work is carried out sequentially, the installed internal shoring is removed in each divided area, and the chipping process, renewal segment installation process, and backfill material filling process are carried out, and by carrying out these processes sequentially for each divided area, stable support by the internal shoring and efficient renewal work can be achieved.

[0015] Another aspect of the method for updating an existing tunnel according to the present invention is to The method is characterized by further comprising a secondary lining construction process of constructing a secondary concrete lining on the inside of the renewal segment.

[0016] According to this aspect, by constructing a secondary concrete lining on the inside of the steel renewal segments, a renewal tunnel with a smooth interior surface can be constructed.

[0017] Another aspect of the method for updating an existing tunnel according to the present invention is to When updating the existing RC tunnel in the area from the middle position to the end of the existing tunnel, and when an existing RC tunnel that is not updated is adjacent to the existing RC tunnel to be updated, A post-installed anchor hole construction process in which a radially chipped surface extending in the radial direction of the tunnel in the existing RC tunnel that is not updated is exposed by the chipping process, and holes for post-installed anchors are drilled in the radially chipped surface; and a post-installed anchor installation step of installing a post-installed anchor into the post-installed anchor hole, In the renewal segment installation step, The bolt holes in the ring joints of the renewal segments are inserted into the post-installed anchors, and the renewal segments are connected to the existing RC tunnel that is not being renewed; or The renewal segment is installed so that the bolt holes in the ring joints of the renewal segment are aligned with the post-installed anchor holes, and post-installed anchors are inserted into the interconnected post-installed anchor holes and bolt holes and driven into the post-installed anchor holes, thereby connecting the renewal segment to the existing RC tunnel that will not be renewed.

[0018] According to this aspect, when updating an existing RC tunnel located in an area extending from the middle to the end of the existing tunnel, i.e., when updating an existing tunnel located on the tunnel entrance side, and the adjacent existing tunnel that is not to be updated is also an RC tunnel, holes for post-installed anchors are drilled into the exposed radial cut surface, post-installed anchors are driven into the post-installed anchor holes, and the existing RC tunnel that will not be updated is connected to the updated segment with the post-installed anchors, thereby enabling efficient and reliable connection construction between the existing RC tunnel and the updated segment. In this case, the order in which the renewal segment is installed in the chipped space and the post-installed anchors are driven into the holes for the post-installed anchors can be either by driving the post-installed anchors first and then inserting them into the bolt holes of the ring joint of the renewal segment, or by installing the renewal segment in the chipped space and aligning the holes for the post-installed anchors with the bolt holes of the ring joint, and then inserting and driving the post-installed anchors into both connecting holes. Furthermore, when multiple renewal segments are connected to an existing RC tunnel that will not be renewed to form a renewal segment ring, and then a separate renewal segment is connected to this renewal segment ring to construct the separate renewal segment ring, the renewal segments that are consecutive in the axial direction of the tunnel will be bolted together via ring joints.

[0019] Another aspect of the method for updating an existing tunnel according to the present invention is to In the renewal segment installation step, Install multiple renewal A segments, A pair of updated B segments are installed above the updated A segment with a space for the updated K segment, and then the pair of updated B segments are lifted upward; After aligning the update K segment in the space for the update K segment, the pair of update B segments are lowered and connected to the update K segment, thereby forming an update segment ring consisting of a plurality of the update segments.

[0020] According to this aspect, when multiple renewal segments are installed circumferentially to form a renewal segment ring, if the pair of segment joints (joint plates) of the renewal K segment that is installed last at or near the top of the renewal segment ring are inclined so as to expand radially outward, i.e., so-called radial K segments, a pair of renewal B segments are lifted upward, and then the renewal K segment is installed in a predetermined installation position (space for renewal K segments), and finally the pair of renewal B segments are lowered downward to connect to the renewal K segment, thereby achieving a smooth connection between the renewal K segment and the pair of renewal B segments on the left and right.

[0021] Another aspect of the method for updating an existing tunnel according to the present invention is to Among the above-mentioned existing tunnels, when updating the existing RC tunnel to be updated from both sides of the axial direction toward the center, The chipping process, the renewal segment installation process, and the backfilling material filling process are set as setting processes, and the setting processes are performed from both sides of the axial direction toward the center, The method further comprises a field-assembled renewal segment installation step of installing a field-assembled renewal segment formed by field assembly in the remaining renewal area in the center.

[0022] According to this aspect, when renewal work is carried out in two parallel directions from both sides of the axial direction of an existing RC tunnel to be renewed toward the center, in the last remaining renewal area in the center, instead of factory-fabricated renewal segments with a fixed width, on-site assembled renewal segments formed by on-site assembly are installed, so that the last renewal segment can be installed accurately according to the width of the remaining renewal area.

[0023] In addition, one aspect of the renewal structure of an existing tunnel according to the present invention is: Among existing tunnels, this is a renewal structure for existing RC tunnels formed by existing RC lining bodies, The existing RC lining body is installed in a chipped space with a chipped surface formed by chipping the inside of the tunnel, and has a plurality of steel renewal segments connected to each other in a ring direction, A feature of this method is that backfill material is filled between the chipped surface and the renewal segment.

[0024] According to this embodiment, a plurality of steel renewal segments connected to each other in a ring direction are installed in the chiseled space formed by chiseling out the empty side of the tunnel of the existing RC lining body, and backfill material such as mortar is filled between the chiseled surface and the renewal segments.As a result, the remaining area of ​​the existing RC lining body on the ground side that has not been chiseled out functions as a retaining wall during the renewal work, eliminating the need for large-scale retaining walls and resulting in a renewal structure that can be constructed with high safety. In addition, since the existing RC lining will not be completely removed and only the part of the ground side that can be left in place will be used as a component of the renewal structure, the height of the steel renewal segments (height of the main girders) can be made as small as possible, which will lead to reduced construction costs during the renewal work.

[0025] Another aspect of the renewal structure of an existing tunnel according to the present invention is: It is characterized by further having a secondary concrete lining provided inside the steel renewal segment.

[0026] According to this aspect, a secondary concrete lining is provided inside the steel renewal segment, thereby forming a renewal tunnel with a smooth interior surface.

[0027] In another aspect of the renewal structure of an existing tunnel according to the present invention, The renewed segment includes a pair of first main girders forming a ring joint, a first skin plate connecting the pair of first main girders, and a pair of first joint plates connected to ends of the first main girders and the first skin plate to form a segment joint, a field-assembled renewal segment ring consisting of field-assembled renewal segments is interposed between a pair of renewal segment rings formed by a plurality of the renewal segments; The on-site assembled renewal segment comprises a pair of split units each having a second main girder bolted to the first main girder on the left and right, a second skin plate connected to the second main girder, and a second vertical rib connected to the second main girder and the second skin plate, and is characterized in that the second main girder of the corresponding split unit is bolted to the first main girder on the left and right, the second skin plates of each split unit are connected to each other by a third skin plate, and the second vertical ribs of each split unit are connected to each other by the third vertical rib.

[0028] According to this aspect, the field-assembled renewal segment that forms the field-assembled renewal segment ring interposed between a pair of renewal segment rings has one second main girder, a second skin plate, and two split units each equipped with a second longitudinal rib. A separate third skin plate is welded to the second skin plates of the two split units. By adjusting the overlap between the third skin plate and the second skin plates on the left and right sides according to the width between the pair of renewal segment rings on the left and right (which can vary as it is the final width remaining after renewal work is performed in two directions from the left and right), a smooth connection between the pair of renewal segment rings on the left and right and the field-assembled renewal segment ring between them is possible. Here, the connection between each field-assembled renewal segment arranged circumferentially that constitutes the field-assembled renewal segment ring can be made, for example, by providing a groove at the end of the second main girder and butt welding, thereby enabling a high-strength connection between the field-assembled renewal segments. [Effects of the Invention]

[0029] According to the existing tunnel renewal method and renewal structure of the present invention, when renewing an existing RC tunnel that forms an existing tunnel, large-scale earth retaining structures are not required and renewal work can be carried out with high safety. [Brief explanation of the drawings]

[0030] [Figure 1A] This is a process diagram of an example of a method for updating the portal side of an existing tunnel in the first embodiment, and is a plan view of the portal side of the vertical shaft and the existing tunnel. [Figure 1B] FIG. 1B is a view taken along the arrow BB in FIG. 1A. [Figure 1C] FIG. 1B is a view taken along the arrow CC in FIG. 1A. [Figure 2A] Following Figure 1, this is a process diagram of an example of a method for updating the portal side, and is a plan view of the portal side of the vertical shaft and existing tunnel. [Figure 2B] FIG. 2B is a view taken along the arrow BB in FIG. 2A. [Figure 2C] FIG. 2B is a view taken along the arrow CC in FIG. 2A. [Figure 3A]Following Figure 2, this is a process diagram of an example of a method for updating the tunnel entrance side, and is a vertical cross-sectional view of the vertical shaft and the entrance side of the existing tunnel. [Figure 3B] FIG. 3B is a view taken along the arrow BB in FIG. 3A. [Figure 3C] FIG. 3B is an enlarged view of part C in FIG. 3A. [Figure 4A] Following Figure 3, this is a process diagram of an example of a method for updating the tunnel entrance side, and is a vertical cross-sectional view of the vertical shaft and the entrance side of the existing tunnel. [Figure 4B] FIG. 4B is a view taken along the arrow BB in FIG. 4A. [Figure 4C] FIG. 4B is an enlarged view of part C in FIG. 4A. [Figure 5A] Following Figure 4, this is a process diagram of an example of a method for updating the tunnel entrance side, and is a vertical cross-sectional view of the vertical shaft and the entrance side of the existing tunnel. [Figure 5B] FIG. 5B is a view taken along the arrow BB in FIG. 5A. [Figure 5C] FIG. 5B is an enlarged view of part C in FIG. 5A. [Figure 6A] FIG. 10 is a plan view of an example of an update segment. [Figure 6B] FIG. 6B is a view taken in the direction of the arrow B in FIG. 6A. [Figure 6C] FIG. 6B is a view taken in the direction of the arrow C in FIG. 6A. [Figure 7A] Following Figure 5, this is a process diagram of an example of a method for renovating the wellhead side, and is a vertical cross-sectional view cut in the middle of the renovated segment ring. [Figure 7B] This is a vertical cross-sectional view of the replacement segment ring, cut in the axial direction of the existing tunnel midway around its circumference. [Figure 8A] Following Figure 7, this is a process diagram of an example of a method for renovating the wellhead side, and is a vertical cross-sectional view cut in the middle of the renovated segment ring. [Figure 8B] This is a vertical cross-sectional view of the replacement segment ring, cut in the axial direction of the existing tunnel midway around its circumference. [Figure 9A] This is a process diagram of an example of a method for updating the tunnel entrance side, following Figure 8, and is a vertical cross-sectional view of the vertical shaft and the tunnel entrance side of the existing tunnel. [Figure 9B] FIG. 9B is an enlarged view of part B in FIG. 9A. [Figure 10A]Following Figure 9, this is a process diagram of an example of a method for updating the tunnel entrance side, and is a vertical cross-sectional view of the vertical shaft and the entrance side of the existing tunnel, as well as a vertical cross-sectional view of an example of an updated structure related to the first embodiment. [Figure 10B] FIG. 9B is an enlarged view of part B in FIG. 9A. [Figure 11] This is a process diagram of an example of a method for updating the center side of an existing tunnel, among the methods for updating an existing tunnel related to the second embodiment, and is a vertical cross-sectional view of the existing tunnel cut along the axial direction. [Figure 12] This is a process diagram of an example of a method for updating the center side, following Figure 11, and is a vertical cross-sectional view of the existing tunnel cut along the axial direction. [Figure 13] This is a process diagram of an example of a method for updating the center side, following Figure 12, and is a vertical cross-sectional view of the existing tunnel cut along the axial direction. [Figure 14] This is a process diagram of an example of a method for updating the center side, following Figure 13, and is a vertical cross-sectional view of the existing tunnel cut along the axial direction. [Figure 15] This is a process diagram of an example of a method for updating the center side, following Figure 14, and is a vertical cross-sectional view of the existing tunnel cut along the axial direction. [Figure 16] Following Figure 15, this is a process diagram of an example of a method for updating the central side, a longitudinal cross-sectional view of an existing tunnel cut along the axial direction, and a longitudinal cross-sectional view of another example of an updated structure related to the second embodiment. [Figure 17A] FIG. 1 is a plan view of an example of a field-assembled renewal segment. [Figure 17B] FIG. 17B is a view seen in the direction of the arrow B in FIG. 17A. [Figure 18] This is a process diagram explaining how to assemble on-site renewal segments in the order of (a), (b), and (c). DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention relates to a method and structure for updating an existing tunnel, and is described below with reference to the accompanying drawings. In this specification and drawings, substantially identical components are designated by the same reference numerals, and redundant description may be omitted.

[0032] [Method and structure for updating existing tunnels according to the first embodiment] First, an example of an existing tunnel renewal method and renewal structure according to the first embodiment will be described with reference to Figures 1 to 10. Here, Figures 1 to 5 and Figures 7 to 10 are, respectively, process diagrams of an example of a portal-side renewal method among the existing tunnel renewal methods according to the first embodiment. Also, Figure 6 is a diagram explaining an example of a renewal segment. Note that Figure 10 is a process diagram of an example of a portal-side renewal method, as well as a longitudinal cross-sectional view of an example of a renewal structure according to the first embodiment.

[0033] The example shown in Figure 1 is an existing RC tunnel 20A that extends from a vertical shaft 10 into the ground G, and at the tunnel entrance side connected to the vertical shaft 10, multiple existing segment rings 24 formed from at least an existing RC lining body 25 are connected.Since two of the existing segment rings 24 connected to the vertical shaft 10 are damaged, these existing segment rings 24 are used as the renewal area for renewal work.

[0034] The existing segment ring 24 that forms the existing RC tunnel 20A in the illustrated example is formed by multiple (three in the illustrated example) existing A segments 25A located below, a pair of existing B segments 25B on the left and right, and an existing K segment 25C that is finally fitted into the pair of existing B segments 25B.

[0035] In the renewal work, first, protective work such as chemical grouting is carried out on the surrounding ground G of the renewal work area from inside the existing RC tunnel 20A, and a ground improvement body G1 is constructed around the renewal work area, as shown in Figure 2. Here, the protective work includes freezing work in addition to chemical grouting work.

[0036] By carrying out protective work, when the renewal area is at great depth or the groundwater level is high and the acting earth pressure water is high, as explained below, the earth pressure water acting on the area of ​​the existing RC covering body 25 that remains uncut and functions as an earth retaining wall can be reduced, thereby improving watertightness and further improving construction safety.

[0037] Furthermore, if the surrounding ground G is hard and the groundwater level is lower than the renewal construction area, and therefore no protective work is required, then no protective work is required (above: protective work construction process).

[0038] Next, as shown in Figure 3, of the two existing segment rings 24 in the renewal area, renewal work is carried out in the X1 direction from the existing segment ring 24 side adjacent to the non-renewal area toward the shaft 10. Here, in the example shown in Figure 3, due to damage to the renewal area, the ring joint bolts 26D connecting the existing RC lining bodies 25 in both the non-renewal area and the renewal area have fractured, and both existing RC lining bodies 25 are misaligned from each other at this ring joint surface.

[0039] In the renewal work, as shown in Figure 3, the tunnel interior space side of the boundary area with the non-renewal area is chipped away using water jet chipping or hand chipping, etc., leaving the tunnel natural ground side exposed with the chipped surface 27 on the tunnel interior space side, thereby forming a chipped space 28.

[0040] Here, the chipped surface 27 has an axial chipped surface 27a (a chipped surface facing the tunnel interior) and a radial chipped surface 27b (a chipped surface extending radially), and the width dimension of the axial chipped surface 27a is set to a dimension sufficient to install the renewal segment 30 in the chipped space 28. On the other hand, the height dimension of the radial chipped surface 27b is set to a dimension that allows the remaining area of ​​the existing RC lining body 25 on the tunnel natural ground side to function as a retaining wall and can accommodate the renewal segment 30.

[0041] In the illustrated example, the existing RC lining body 25 is equipped with inner main reinforcement 26A extending in the circumferential direction, outer main reinforcement 26B also extending in the circumferential direction, and further with distribution reinforcement 26C surrounding these inner main reinforcement 26A and outer main reinforcement 26B, but by leaving the outer main reinforcement 26B, the area that remains uncut is maintained as a structure that can function as an earth retaining wall.

[0042] As shown in FIG. 3, when chipping the existing segment ring 24 in the circumferential direction, the existing segment ring 24 is divided into two halves, an upper half and a lower half, of the spring line SL, and the lower half is chipped first (this is the chipping process).

[0043] As shown in Figure 4, the inner main reinforcement 26A and other components that were in the chipped space 28 are completely cut and removed, and holes 29A for post-installed anchors are drilled at predetermined intervals in the circumferential direction on the ring joint surface 25a that is in the non-renewal area and exposed to the chipped space 28 (post-installed anchor hole construction process).

[0044] Next, post-installed anchors 29B (Chemical Anchor (registered trademark)) are driven into each post-installed anchor hole 29A (post-installed anchor installation step).

[0045] Next, as shown in Figure 5, the bolt hole 31a (see Figure 6) in the main girder 31 (ring joint) of the steel renewal segment 30 is inserted into the installed post-installed anchor 29B, and brought into contact with the ring joint surface 25a of the existing RC lining body 25 in the non-renewal area, and the post-installed anchor 29B is protruded inside the main girder 31 of the renewal segment 30 and tightened with a nut 29C, thereby connecting the existing RC lining body 25 in the non-renewal area and the renewal segment 30 via the ring joint.

[0046] Here, as shown in Figure 6, the steel renewal segment 30 has a pair of main girders 31, curved skin plates 32 connected to them, a pair of joint plates 33 (segment joints) connected to the ends of the pair of main girders 31 and skin plates 32, and vertical ribs 34 connected to the pair of main girders 31 and skin plates 32.

[0047] The main girder 31 forming the ring joint has bolt holes 31a, and the joint plate 33 forming the segment joint also has bolt holes 33a. Furthermore, the skin plate 32 has a backfilling material filling port 37 on its back surface for filling with backfilling material 39.

[0048] Multiple renewal segments 30 are installed sequentially in the circumferential direction, and adjacent renewal segments 30 are connected by inserting segment joint bolts (not shown) into the bolt holes 33a in both joint plates 33 and tightening the nuts.

[0049] Furthermore, there are multiple update A segments, a pair of update B segments, and one update K segment, and the update A segments are installed in the lower half, the remaining pair of update B segments are installed in the upper half, and finally the update K segment is installed so that it is fitted between the pair of update B segments (this is the update segment installation process).

[0050] Although the illustrated example shows a flow in which construction is performed in the order of post-installed anchor hole construction step, post-installed anchor construction step, and renewal segment installation step, construction may also be performed in the order of post-installed anchor hole construction step, renewal segment installation step, and post-installed anchor construction step. That is, in this construction method, renewal segment 30 is installed so that bolt hole 31a in main girder 31 provided on renewal segment 30 is aligned with post-installed anchor hole 29A, and post-installed anchor 29B is inserted through post-installed anchor hole 29A and bolt hole 31a, which are connected to each other, and driven into post-installed anchor hole 29A.

[0051] In this way, after installing multiple renewal segments 30 in the chipped space 28 in the lower half, the gable formwork K is installed as shown in Figure 7, and the ends are filled with filler material 38 (filler mortar).After that, a filling hose H is connected to the backfill material filling port 37 of the renewal segment 30, and backfill material 39 (backfill mortar such as non-shrink mortar) is filled between the back of the skin plate 32 and the axial chipped surface 27a (this is the backfill material filling process).

[0052] Next, as shown in Figure 8, scaffolding F is installed inside the existing RC tunnel 20A, and in the upper half above the spring line SL, a chipping space 28 is constructed using the same procedure as in the lower half (chipping process), multiple holes 29A for post-installed anchors are constructed (post-installed anchor hole construction process), post-installed anchors 29B are driven into each post-installed anchor hole 29A (post-installed anchor construction process), multiple renewal segments 30 are installed in sequence in the circumferential direction (renewal segment installation process), and backfill material 39 is filled behind each renewal segment 30 (backfill material filling process), thereby constructing a circumferentially continuous renewal segment ring 40.

[0053] Here, when installing the replacement segments in the upper half, a pair of replacement B segments is installed, and the replacement K segment is installed by fitting it between them. If the pair of segment joints (joint plates) of the replacement K segment are inclined so that they expand radially outward, so-called radial K segments, it is preferable to lift the pair of replacement B segments upward, then install the replacement K segment in the specified installation position (replacement K segment space), and finally lower the pair of replacement B segments downward to connect them to the replacement K segment, thereby achieving a smooth connection between the replacement K segment and the pair of replacement B segments on the left and right.

[0054] Through the series of construction steps described above, the existing segment ring 24 in the non-renewal area and the renewal segment ring 40 in the adjacent renewal area are connected by multiple post-installed anchors 29B.

[0055] Next, as shown in Figure 9, a new renewal segment ring 40 is constructed in the area adjacent to the already constructed renewal segment ring 40 using a set process of chipping, renewal segment installation, and backfill material filling, and the preceding renewal segment ring 40 and both main girders 31 are connected with ring joint bolts 36 to form a structure in which multiple renewal segment rings 40 (eight in the illustrated example) are connected in the renewal area.

[0056] Next, as shown in FIG. 10, a secondary concrete lining 50 is constructed inside the renewed segment ring 40 to form a renewed structure 100 (secondary lining construction process).

[0057] According to the illustrated method of updating an existing tunnel, the empty side of the existing RC lining 25 is chipped away to form a chipped space 28, and steel renewal segments 30 are installed in the chipped space 28 to perform the update.This leaves a portion of the ground side of the existing RC lining 25 remaining during the update work process and functions as an earth retaining wall, making it possible to carry out the update work with high safety and eliminating the need for large-scale earth retaining walls.

[0058] [Second embodiment of the existing tunnel renewal method and renewal structure] Next, an example of an existing tunnel renewal method and renewal structure according to the second embodiment will be described with reference to Figures 11 to 18. Here, Figures 11 to 16 are, in order, process diagrams of an example of a method for renewing the center side of the existing tunnel renewal method according to the second embodiment. Also, Figure 17 is a diagram explaining an example of a field-assembled renewal segment, and Figure 18 is a process diagram explaining, in the order of (a), (b), and (c), a method for assembling the field-assembled renewal segment. Note that Figure 16 is not only a process diagram of an example of a central renewal method, but also a longitudinal cross-sectional view of an example of a renewal structure according to the second embodiment.

[0059] The example shown in Figure 11 is a heterogeneous tunnel that contains a section formed by an existing steel tunnel 20B and a section formed by an existing RC tunnel 20A.Due to damage to some of the existing RC tunnel 20A, multiple (three in the illustrated example) existing segment rings 24 that form this existing RC tunnel 20A are used as the renewal area for renewal work.

[0060] As shown in Figure 12, prior to the construction of the protective work during the renewal work, in addition to the existing segment rings 24 that make up the existing RC tunnel 20A in the renewal area, internal support structures N made of H-shaped steel are installed to support the existing segment rings that make up the existing steel tunnel 20B on the left and right of it from the air side of the tunnel (support process).

[0061] In this way, by supporting the existing segment rings in the area where the protective work is to be carried out from the air side inside the tunnel, the chipping area where the chipping space 28 is formed can be stably supported from the air side inside the tunnel while the renewal work is carried out.

[0062] Following the support process, protective work such as chemical injection work is carried out on the surrounding ground G of the renewal construction area from inside the existing RC tunnel 20A, and a ground improvement body G1 is constructed around the renewal construction area (protective work construction process).

[0063] As shown in FIG. 13, the renewal work in the illustrated example is carried out in a manner that renewal is carried out in the X2 direction in parallel from both sides of the axial direction of the existing RC tunnel 20A in the renewal area toward its center.

[0064] The existing segment ring 40 is constructed by carrying out a chipping process in which the tunnel interior side of the existing RC lining body 25 that constitutes the existing segment ring 24 is chipped to form a chipped space 28, a chipped segment installation process in which the updated segments 30 are installed in the chipped space 28, and a backfill filling process in which backfill material 39 is filled behind the updated segments 30. During the chipping process, the internal support N that obstructs the chipping work is removed before the chipping work is carried out.

[0065] As shown in Figures 14 and 15, the set processes are the removal of the obstructing internal support work N, the chipping process, the renewal segment installation process, and the backfill material filling process, and the renewal segment rings 40 are constructed sequentially in the X2 direction from both sides of the renewal area toward the center, and the renewal segment rings 40 are connected to each other via ring joints.

[0066] As shown in Figure 16, in the last remaining renewal area in the center, a plurality of field-assembled renewal segments 60 formed by field assembly are installed circumferentially, and a field-assembled renewal segment ring 70 consisting of the plurality of field-assembled renewal segments 60 is constructed to form a renewal structure 100A (field-assembled renewal segment installation process). Note that, although not shown in the figure, like the renewal structure 100, the renewal structure 100A may also have a secondary lining installed by a secondary lining process.

[0067] As shown in Figures 17A and 17B, the field-assembled renewal segment 60 has a pair of split units 65, and a third skin plate 66 and a third longitudinal rib 67 that connect the pair of split units 65.

[0068] The split unit 65 comprises one second main girder 61, a second skin plate 62 connected to the second main girder 61, and a second longitudinal rib 63 connected to the second main girder 61 and the second skin plate 62.

[0069] As shown in Figure 18(a), by bolting the second main girder 61 of each of the two split units 65 to the first main girder 31 of the renewal segment 30 that forms the renewal segment ring 40 on the left and right sides that has already been constructed using ring joint bolts 36, a space S is created between the second skin plates 62 of the two split units 65.

[0070] Since multiple renewal segment rings 40 have been installed sequentially in two directions from the left and right, the width of this space S can vary depending on manufacturing errors in the renewal segments 30 and construction errors when installing the renewal segment rings 40.

[0071] As shown in Figure 18(b), by overlapping the left and right ends of the third skin plate 66 with the left and right second skin plates 62 and welding the overlap, a field-assembled renewal segment 60 can be manufactured on site according to the space S, which can have a variety of widths, and the left and right renewal segments 30 can be connected via the field-assembled renewal segment 60.

[0072] As shown in Figure 18(c), the on-site assembled renewal segment 60 is manufactured (constructed) by overlapping the left and right ends of the third vertical rib 67 with the second vertical rib 63 of the left and right renewal segments 30 and welding the overlapping portions together.

[0073] The connection between multiple field-assembled renewal segments 60 lined up circumferentially can be achieved, for example, by creating a groove at the end of the second main girder 61 and butt-welding two circumferentially adjacent second main girders 61 together, thereby manufacturing (constructing) the field-assembled renewal segment ring 70 while ensuring high-strength connections between the field-assembled renewal segments.

[0074] Even with the method of updating an existing tunnel shown in the illustration, the air side of the existing RC lining 25 is chipped away to form a chipped space 28, and steel renewal segments 30 are installed in the chipped space 28 to perform the update.This leaves a portion of the ground side of the existing RC lining 25 remaining during the update work process and functions as an earth retaining wall, making it possible to carry out the update work with high safety, without the need for large-scale earth retaining walls.

[0075] It should be noted that the present invention is not limited to the configurations shown here, and other embodiments may be possible in which other components are combined with the configurations described in the above embodiments. In this regard, the present invention can be modified within the scope of the present invention, and can be appropriately determined depending on the application form. [Explanation of symbols]

[0076] 10: Shaft 20: Existing tunnel 20A: Existing RC tunnel 20B: Existing steel tunnel 21: Mine mouth side area 22: Central area 24: Existing segment ring 25: Existing RC lining (existing RC segment) 25A: Existing A segment 25B: Existing B segment 25C: Existing K segment 25a: Ring joint surface 26A: Medial main reinforcement 26B: Lateral main reinforcement 26C: Distribution reinforcement 26D: Ring joint bolt 27: Chipped surface 27a: Axial cutting surface 27b: Radial cutting surface 28: Chipping space 29A: Post-installed anchor hole 29B: Post-installed anchor 29C: Nut 30: Update segment 31: First main girder (main girder, ring joint) 31a: Ring joint bolt hole (bolt hole) 32: First Skin Plate (Skin Plate) 33: First joint plate (joint plate, segment joint) 33a: Segment joint bolt hole (bolt hole) 34: Vertical rib 36: Ring joint bolt 37: Backfilling material filling port 38: Filling material 39: Backfill material 40: Update segment ring 50: Secondary lining 60: On-site assembly renewal segment 61: Second main girder 62: Second skin plate 63: Second vertical rib 65: Split unit 66: 3rd Skin Plate 67: Third vertical rib 70: On-site assembly renewal segment ring 100, 100A: Updated structure G: Ground G1: Ground improvement body SL: Spring Line K: Gable formwork H: Filling hose F: Scaffolding N: Internal shoring S: Space

Claims

1. A method for updating an existing tunnel, which updates an existing RC tunnel formed by an existing RC lining, a chipping process in which the tunnel interior side of the existing RC lining body is chipped away, leaving the tunnel natural ground side and exposing the chipped surface to the tunnel interior side, thereby forming a chipped space; A renewal segment installation process for installing a plurality of steel renewal segments in the chipping space; A method for renewing an existing tunnel, characterized by including a backfill filling process in which backfill material is filled between the chipped surface and the renewal segment.

2. A method for updating an existing tunnel as described in claim 1, further comprising a protective work construction process in which protective work, such as chemical injection work or freezing work, is carried out from inside the existing RC tunnel on the ground behind the existing RC tunnel to be updated, and the protective work construction process is carried out prior to the chipping process.

3. 3. A method for updating an existing tunnel as described in claim 1 or 2, further comprising a support step of installing internal support that supports the existing RC lining body from the air side inside the tunnel.

4. 2. A method for updating an existing tunnel as described in claim 1, further comprising a secondary lining construction process for constructing a secondary concrete lining on the inside of the renewal segment.

5. When updating the existing RC tunnel in an area extending from the middle position to the end of the existing tunnel, and when an existing RC tunnel that will not be updated is adjacent to the existing RC tunnel to be updated, a post-installed anchor hole construction process in which a radially chipped surface extending in the radial direction of the tunnel in the existing RC tunnel that is not to be renewed is exposed by the chipping process, and holes for post-installed anchors are drilled into the radially chipped surface; and a post-installed anchor installation step of installing a post-installed anchor into the post-installed anchor hole, In the renewal segment installation step, The renewal segment is connected to the existing RC tunnel that is not being renewed while inserting the installed post-installed anchor into the bolt hole in the ring joint provided in the renewal segment, or A method for updating an existing tunnel as described in claim 1, characterized in that the update segment is installed so that the bolt holes in the ring joints provided on the update segment are aligned with the post-installed anchor holes, and post-installed anchors are inserted into the interconnected post-installed anchor holes and bolt holes and driven into the post-installed anchor holes, thereby connecting the update segment to the existing RC tunnel that will not be updated.

6. In the renewal segment installation step, Install multiple renewal A segments, A pair of updated B segments are installed above the updated A segment with a space for the updated K segment, and then the pair of updated B segments are lifted upward; 2. A method for updating an existing tunnel as described in claim 1, characterized in that after aligning the updated K-segment in the space for the updated K-segment, the pair of updated B-segments are lowered and connected to the updated K-segment to form an updated segment ring consisting of a plurality of the updated segments.

7. In the case of updating the existing RC tunnel from both sides of the axial direction toward the center of the existing tunnel, The chipping process, the renewal segment installation process, and the backfilling material filling process are set as setting processes, and the setting processes are performed from both sides of the axial direction toward the center, 2. The method for renovating an existing tunnel as described in claim 1, further comprising a step of installing field-assembled renovation segments formed by field assembly in the remaining renovation area in the center.

8. Among existing tunnels, this is a renewal structure for an existing RC tunnel formed by an existing RC lining body, The existing RC lining body is installed in a chipped space having a chipped surface formed by chipping the tunnel interior side, and has a plurality of steel renewal segments connected to each other in a ring direction, A renewal structure for an existing tunnel, characterized in that backfill material is filled between the chipped surface and the renewal segment.

9. The renewal structure for an existing tunnel as described in claim 8, further comprising a secondary concrete lining provided inside the steel renewal segment.

10. The renewed segment comprises a pair of first main girders forming a ring joint, a first skin plate connecting the pair of first main girders, and a pair of first joint plates connected to ends of the first main girders and the first skin plate to form a segment joint, a field-assembled renewal segment ring consisting of field-assembled renewal segments is interposed between a pair of renewal segment rings formed by a plurality of the renewal segments; The on-site assembled renewal segment comprises a pair of split units each having a second main girder bolted to the first main girders on the left and right, a second skin plate connected to the second main girder, and a second longitudinal rib connected to the second main girder and the second skin plate, wherein the second main girder of the corresponding split unit is bolted to the first main girders on the left and right, the second skin plates of each split unit are connected to each other by a third skin plate, and the second longitudinal ribs of each split unit are connected to each other by the third longitudinal rib. A renewal structure for an existing tunnel as described in claim 8 or 9, characterized in that

Images