Construction method for invert structure

Abstract

To provide a construction method for an invert structure capable of effectively preventing deformation of an existing tunnel lining in a stable state.SOLUTION: When forming one-side block group 20X by arranging multiple PCa concrete blocks 20 vertically and horizontally in a row in one side region 55X in the transverse direction of a tunnel 30 prior to the other side region 55Y, a present invention comprises a step of filling a filling solidification material 22 to solidify at least one row of blocks 20Z arranged in a row in the transverse direction of the tunnel 30 into gaps 21a between the row of blocks and adjacent receiving base portions 31c, gaps 21b between the row of blocks and adjacent PCa concrete blocks 20, and interval portions 63 between the row of blocks and end face portions 61a of a foundation base plate 61 of the other side region 55Y, thereby forming a first closing portion covering body 65 that is continuous in a ring shape as a single unit in the circumferential direction in a portion of the row of blocks 20Z.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a construction method for an invert structure, and more particularly to a construction method for an invert structure using PCa concrete blocks in a mountain tunnel. [Background technology]

[0002] A mountain tunnel is a tunnel formed by excavating a self-supporting and relatively stable ground such as a rock mass, and the excavated inner wall surface is covered with a primary lining and a secondary lining made of concrete or mortar. That is, the inner wall surface of a mountain tunnel is excavated, for example, while performing blasting, etc., and then a protective layer is formed by spraying mortar or concrete to form a primary lining, and then, for example, a known tunnel lining formwork is installed inside the protective layer formed by the primary lining, and a lining body made of concrete of a predetermined thickness is formed as a secondary lining from the side wall part to the upper arch-shaped part of the tunnel. Furthermore, in the lining body formed previously from the both side walls of the tunnel to the upper arch-shaped part, a lining body of the bottom invert part is integrally formed with concrete to a predetermined thickness in the transverse direction of the tunnel between the receiving parts at the lower ends of the pair of side walls, so that the entire circumference of the inner wall surface of the mountain tunnel is continuously covered with the secondary lining.

[0003] In addition, since mountain tunnels are formed by excavating relatively stable ground, some tunnels constructed several decades ago, for example, omit the invert lining and form a secondary lining only in the area from the side wall of the tunnel to the upper arch-shaped part. For such mountain tunnels that omit the invert lining, it is being considered to form a new invert lining to prevent future effects such as swelling of the base.

[0004] As a method for forming the invert lining at the bottom of the tunnel, continuing from the lining installed earlier from the side wall to the upper arch-shaped part of the tunnel, cast-in-place concrete has been used in the past (see, for example, Patent Document 1), but finishing the upper surface of the invert lining to give it a curved shape requires a high level of skill. Furthermore, when cast-in-place concrete is used, it takes a considerable amount of time for the poured concrete to harden and undergo a prescribed curing period, and therefore, particularly when a new invert lining is formed on the lining from the side wall to the upper arch-shaped part, where the invert lining is omitted, traffic through the tunnel will be blocked for a long period of time, so it is desirable to be able to complete the construction as quickly as possible.

[0005] For this reason, it has been considered to shorten the construction period by forming the lining of the invert section using concrete members made of precast concrete that have been manufactured in advance in a factory or the like (see, for example, Patent Document 2 and Patent Document 3).In addition, when forming a new lining of the invert section using concrete members (blocks) made of precast concrete for an existing mountain tunnel that was constructed several decades ago, for example, it is desirable to be able to carry out construction work while ensuring passage on the passageway without completely blocking traffic through the tunnel, and therefore a technology has been developed that allows the lining of the invert section of a mountain tunnel to be constructed for each side area in the transverse direction of the tunnel (see, for example, Patent Document 4). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2020-159060 A [Patent Document 2] JP 2013-28898 A [Patent Document 3] JP 2018-123528 A [Patent Document 4] JP 2000-145390 A Summary of the Invention [Problem to be solved by the invention]

[0007] In the method of forming an invert described in Patent Document 4, while ensuring passage on the passage in the other side area in the transverse direction of the tunnel, the passage in one side area and the foundation base below it are excavated to form an excavation trench, and then a number of blocks that make up the invert section are arranged side by side at the bottom of the excavation trench that has been formed. Furthermore, the side of the foundation base below the passage in the other side area where passage is ensured is retained by the rising parts of the blocks that are arranged adjacent to that other side area.

[0008] In addition, the applicants of the present application have proposed, for example, in Patent Application No. 2023-058346, a construction method for an invert structure using PCa concrete blocks, which constitutes the covering body of the invert section, in each side region in the transverse direction of the tunnel, which makes it possible to form the passageway and the foundation base below it in one side region while maintaining the passageway and the foundation base below it in a stable state in the other side region with a simple configuration.

[0009] However, in these conventional invert construction methods using concrete blocks, when forming an invert structure in one side region prior to the other side region in the transverse direction of the tunnel, for example, when the foundation base of the invert part of the one side region is excavated, the annular support structure, which is formed integrally with the existing tunnel lining body of the arch-shaped part from the side wall of the tunnel to the upper part and the foundation base of the invert part, and which is continuous in a curved ring shape in the cross section, becomes discontinuous at the excavated foundation base. If such a state in which the annular support structure of the existing tunnel lining body and the foundation base is discontinuous continues for a long period of time, for example, until the invert structure of one side region and the invert structure of the other side region are integrated and the lining is closed, depending on the geology of the surrounding ground, it is considered that the existing tunnel lining body will deform and affect the surrounding ground.

[0010] For this reason, there is a need to develop a construction method that can stably prevent the existing tunnel lining from becoming easily deformed from the time when the foundation base is excavated in one or the other side area of ​​a mountain tunnel, until the invert structure in one side area and the invert structure in the other side area are integrated and the lining is closed.

[0011] The present invention aims to provide a construction method for an invert structure that can effectively prevent the existing tunnel lining from becoming easily deformed in a stable manner, from the time when the foundation base is excavated in one or the other side region of a mountain tunnel, until the invert structure in one side region and the invert structure in the other side region are integrated and the lining is closed. [Means for solving the problem]

[0012] The present invention relates to a construction method for an invert structure using PCa concrete blocks, which constitutes an invert lining provided in an invert section of a mountain tunnel, and the PCa concrete blocks are formed as hexahedral blocks having curved upper and lower surfaces so as to have a curved shape along the cross-sectional shape of the invert lining. In each of one side region and the other side region in the cross direction of the tunnel, a plurality of the PCa concrete blocks are arranged in series in the cross direction of the tunnel and installed in the invert section, with gaps maintained between the receiving base portion of the lower end of the adjacent side wall lining body and between the adjacent PCa concrete blocks, and are also arranged in series in the axial direction of the tunnel and installed in the invert section, with gaps maintained between the adjacent PCa concrete blocks. Thus, one side block group and another side block group are formed, and the plurality of PCa concrete blocks arranged in series vertically and horizontally in each of the one side block group and the other side block group are arranged in series with each of the adjacent receiving base portions. The invert section lining is formed by filling and solidifying a filling solidification material into gaps between adjacent receiving base portions, gaps between adjacent PCa concrete blocks, intervals between the one-side block group and the other-side block group, and gaps below the hexahedral underside portion communicating with these gaps and intervals, thereby forming an integrated state via the filling solidification material. When forming the one-side block group by arranging a plurality of the PCa concrete blocks vertically and horizontally in one side region in the transverse direction of the tunnel prior to the other side region, at least one row of blocks arranged in the transverse direction of the tunnel is filled with filling solidification material in the gaps between adjacent receiving base portions, gaps between adjacent PCa concrete blocks, and intervals between the end face portion of the foundation base plate of the other side region, thereby forming a first closing section lining that is continuous in a ring shape as a single unit in the circumferential direction in the at least one row of block rows. This object has been achieved by providing a construction method for an invert section structure that includes a step of forming a first closing section lining that is continuous in a ring shape as a single unit in the circumferential direction in the at least one row of block rows.

[0013] The present invention also relates to a construction method for an invert structure using PCa concrete blocks that constitute an invert lining provided in an invert section of a mountain tunnel, the PCa concrete blocks being formed as hexahedral blocks having curved upper and lower surfaces so as to have a curved shape that follows the cross-sectional shape of the invert lining, and in each of one side region and the other side region in the transverse direction of the tunnel, a plurality of the PCa concrete blocks are arranged in series in the transverse direction of the tunnel and installed in the invert section, with gaps maintained between the support portions of the lower ends of the adjacent side wall lining bodies and between the adjacent PCa concrete blocks, and are also arranged in series in the axial direction of the tunnel and installed in the invert section, with gaps maintained between the adjacent PCa concrete blocks, thereby forming a one-side block group and an other-side block group, and the plurality of the PCa concrete blocks arranged in series vertically and horizontally in each of the one-side block group and the other-side block group are arranged in series to form a one-side block group and an other-side block group, with gaps maintained between the adjacent support portions and between the adjacent PCa concrete blocks, and filling and solidifying a filling solidification material into gaps between the PCa concrete blocks, intervals between the one-side block group and the other-side block group, and gaps below the bottom surface of the hexahedron communicating with these gaps and intervals, thereby forming the invert section lining, and when forming the other-side block group by arranging a plurality of the PCa concrete blocks vertically and horizontally in a row adjacent to one side region in the other side region in the transverse direction of the tunnel, filling and solidifying a filling solidification material into gaps between the adjacent receiving base portions, gaps between the adjacent PCa concrete blocks, and intervals between the end face portions of the one-side structure of the one-side block group formed prior to the one side region in the one side region in the transverse direction of the tunnel, in at least one row of blocks arranged in a row, forming a second closing section lining that is continuous in a ring shape as a whole in the circumferential direction in the at least one row of blocks.The above objective has been achieved.

[0014] In the construction method of the invert structure of the present invention, it is preferable that displacement measuring devices are attached to multiple predetermined positions of an existing tunnel lining, and in the process of forming the first closing portion lining or the process of forming the second closing portion lining, the first closing portion lining or the second closing portion lining is formed so as to be continuous in a ring shape as a single unit in the circumferential direction in at least one row of blocks connected in the transverse direction of the tunnel, adjacent to the position where the displacement measuring device where the displacement is measured is attached. Effect of the Invention

[0015] According to the construction method of the invert structure of the present invention, it is possible to effectively prevent the existing tunnel lining from becoming easily deformed in a stable manner from the time when the foundation base is excavated in one or the other side region of the mountain tunnel until the invert structure in one side region and the invert structure in the other side region are integrated and the lining is closed. [Brief description of the drawings]

[0016] [Figure 1] This is a simplified cross-sectional view illustrating a mountain tunnel in which an invert lining is formed using a construction method for an invert structure according to a preferred embodiment of the present invention. [Diagram 2] This is a schematic top view of Figure 1 viewed from the AA direction, explaining an invert section lining in which one side invert section structure and the other side invert section structure are integrated. [Diagram 3] This is a simplified cross-sectional view illustrating the situation in which one side invert structure is engaged in one side area of ​​the tunnel in the transverse direction while ensuring passage in the other side area. [Figure 4] FIG. 13 is a schematic top view of a one-side block group provided in one side region. [Diagram 5]5 is a schematic top view taken along line BB in FIG. 4 for explaining a one-side block group provided in one of the half-side regions. FIG. [Figure 6] FIG. 11 is a schematic top view illustrating a process for forming a first closing portion covering body. [Figure 7] This is a simplified top view illustrating the process of forming a second closing portion covering body, showing the soil backfilled in one side area without showing it. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] A construction method for an invert structure in a mountain tunnel according to a preferred embodiment of the present invention is adopted as a construction method for forming the invert structure 32 on both left and right sides, which are components of the invert structure 32, on each side of the transverse center line C of the tunnel, when forming a new invert structure 32 on the bottom portion 30a of the mountain tunnel 30 in continuity with the existing tunnel lining 31 in the area from both side wall portions 31a to the upper arch-shaped portion 31b, which has been formed in advance to cover the inner wall surface of the tunnel, in an existing mountain tunnel 30 shown in Figure 1.

[0018] In this embodiment, the mountain tunnel 30 is a tunnel that was constructed, for example, several decades ago, and the ground to be excavated was stable, so at the time of construction, the lining 31 covering the inner wall surface of the tunnel was formed only from the side wall portions 31a on both sides to the upper arch-shaped portion 31b. However, as time passed, concerns arose about the effects of ground swelling of the base portion 30a, etc., so a new invert lining 32 is formed using invert structural members 10X and 10Y on both the left and right sides, as shown in Figure 2.

[0019] In addition, when a new invert lining 32 is formed in an existing mountain tunnel 30, it is desirable to be able to carry out the work while securing the passageway without completely blocking traffic through the tunnel, so in this embodiment, as shown in Fig. 3, each step of forming a one-side invert structure 10X is carried out in one side region 55X while securing the passageway 60 in the other side region 55Y in the transverse direction of the tunnel. The construction method of the invert structure in a mountain tunnel in this embodiment is intended to effectively prevent the existing tunnel lining 31 in the region from the side wall portions 31a on both sides to the upper arch-shaped portion 31b from being easily deformed when constructing the invert structures 10X, 10Y for each side region 55X, 55Y in the transverse direction of the tunnel 30 (see Figs. 1 and 2), and to effectively prevent the influence on the surrounding ground.

[0020] The construction method of the invert structure of this embodiment is a construction method in which the invert structures 10X, 10Y using PCa concrete blocks 20 that constitute the invert lining 32 to be provided in the invert 33 of the mountain tunnel 30 are divided into one-side regions 55X, 55Y on both sides of the central portion in the transverse direction, and as shown in Figures 1 and 2, each PCa concrete block 20 is formed as a hexahedral block having curved upper surface portion 20a and lower surface portion 20b so as to have a curved shape that follows the cross-sectional shape of the invert lining 32 (see Figure 5). In each of one side region 55X and the other side region 55Y in the transverse direction of the tunnel 30, a plurality of PCa concrete blocks 20 are arranged in series in the transverse direction of the tunnel 30 and installed in the invert section 33, with gaps 21a, 21b maintained between the receiving base portion 31c at the lower end of the adjacent side wall covering body 31a and between adjacent PCa concrete blocks 20, and are also arranged in series in the axial direction of the tunnel 30 and installed in the invert section 33, with gaps 21b maintained between adjacent PCa concrete blocks 20, thereby forming a one side block group 20X and the other side block group 20Y. In each of these one-side block group 20X and other-side block group 20Y, the multiple PCa concrete blocks 20 are arranged vertically and horizontally in succession, and the gaps 21a between each adjacent receiving base portion 31c, the gaps 21b between adjacent PCa concrete blocks 20, the spacing portion 51 between the one-side block group 20X and the other-side block group 20Y, and the gaps 21c below the hexahedral underside portion communicating with these gaps 21a, 21b and the spacing portion 51 are filled with filling solidification material 22 and solidified, thereby forming the invert portion covering body 32.The construction method of the invert structure of this embodiment includes a step of forming a one-side block group 20X by arranging a plurality of PCa concrete blocks 20 vertically and horizontally in a row in one side region 55X of the transverse direction of the tunnel 30, prior to the other side region 55Y (see Figures 4 and 5), and then, as shown in Figure 6, filling and solidifying filling solidification material 22 in the gaps 21a between adjacent receiving base portions 31c of at least one row of blocks 20Z arranged in a row in the transverse direction of the tunnel 30, the gaps 21b between adjacent PCa concrete blocks 20, and the interval portions 63 between the end face portions 61a of the foundation base plate 61 of the other side region 55Y, thereby forming a first closing portion covering body 65 that is continuous in a ring shape as a single unit in the circumferential direction in the at least one row of block rows 20Z.

[0021] In addition, in the construction method of the invert structure of this embodiment, after the step of forming the above-mentioned first closing portion lining body 65, or separately from the step of forming the above-mentioned first closing portion lining body 65, as shown in FIG. 7, when forming the other side block group 20Y by arranging a plurality of PCa concrete blocks 20 vertically and horizontally in series following the one side block group 20X of one side region 55X in the other side region 55Y in the transverse direction of the tunnel 30, at least one row of blocks 20Z arranged in series in the transverse direction of the tunnel 30 is arranged in series. The method includes a step of filling and solidifying filling solidification material 22 into gaps 21a between adjacent receiving base portions 31, gaps 21b between adjacent PCa concrete blocks 20, and interval portions 64 between end face portions 10Xa on the other side region 55Y side of one-side structure 10X made of one-side block group 20X formed prior to one side region 55X, thereby forming a second closing portion covering body 66 that is continuous in a ring shape as a single unit in the circumferential direction in at least one block row 20Z'.

[0022] Furthermore, in the construction method of the invert structure of this embodiment, displacement measuring devices 67 (see Figures 6 and 7) are attached at multiple predetermined positions of the existing tunnel lining 31, preferably in the area extending from both side wall portions 31a to the upper arch-shaped portion 31b, for example at predetermined intervals in the axial direction of the tunnel 30, and in the process of forming the above-mentioned first closing portion lining 65 or the process of forming the above-mentioned second closing portion lining 66, the first closing portion lining 65 or the second closing portion lining 66 is formed in a circumferentially integral and annular manner in at least one row of block rows 20Z, 20Z' arranged adjacent to the position where the displacement measuring device 67 where the displacement is measured is attached, in the portion of at least one row of block rows 20Z, 20Z' arranged adjacent to the transverse direction of the tunnel,

[0023] In this embodiment, the invert structure 10X, 10Y constituting the invert lining 32 is constructed by dividing it into one side region 55X, 55Y on both sides of the central part of the tunnel 30 in the transverse direction in the invert 33 of the mountain tunnel 30 as shown in Figures 1 and 2, and is a structure of the invert 33 using PCa concrete blocks 20 that are integrally constructed to constitute the invert lining 32. The PCa concrete blocks 20 are formed as hexahedral blocks having curved upper surface portion 20a and lower surface portion 20b so as to have a curved shape along the cross-sectional shape of the invert lining 32, similar to the PCa concrete blocks used in the construction method of the invert structure of Japanese Patent Application No. 2023-058346 (see Figure 5).

[0024] That is, the PCa concrete block 20 is a precast concrete block of moderate weight and size that is easy to handle and manufactured in a factory or the like in advance. This makes it possible to lay the blocks in each of the one-side regions 55X and 55Y in a state of being arranged vertically and horizontally without much effort. These PCa concrete blocks 20 can be formed to have a hexahedral shape with a width of about 1385 to 1435 mm in the transverse direction of the tunnel 30, a vertical width of about 730 mm in the axial direction, and a height of about 500 mm, similar to the PCa concrete block used in the construction method of the invert structure of Japanese Patent Application No. 2023-058346, and a weight of about 1000 to 1500 kg. In addition, similar to the PCa concrete blocks used in the construction method of the invert structure of Patent Application No. 2023-058346, the PCa concrete blocks 20 have bolt boxes 23 and female thread anchors 24, etc., embedded and fixed in predetermined positions for connecting adjacent PCa concrete blocks 20 with bolt members (see Figure 4), and bolt insertion and screw holes, filler injection holes, spacer jigs, hanging jigs, etc. are provided in appropriate positions.

[0025] In addition, the PCa concrete blocks 20 arranged in a row in each of the one-side regions 55X and 55Y are arranged in a row ... The gap 51 between the one-side block group 20X in one side region 55X and the other-side block group 20Y in the other side region 55Y may preferably have a gap width of 100 to 130 mm.

[0026] In this embodiment, similar to the construction method of the invert structure of Patent Application No. 2023-058346, for example, in each one-side region 55X, 55Y, a one-side block group 20X and an other-side block group 20Y made of a plurality of PCa concrete blocks 20 arranged vertically and horizontally in a row are integrated using a filling solidification material 22 to form a one-side invert section structure 10X and an other-side invert section structure 10Y according to the following steps, and by further integrating these one-side invert section structure 10X and other-side invert section structure 10Y, it is possible to form an invert section covering body 32 installed across the entire width of the invert section 33 in the transverse direction.

[0027] That is, as shown in Figs. 4 and 5, for example, in one side region 55X in the transverse direction of the tunnel 30, a plurality of PCa concrete blocks 20A, 20B, 20C are arranged in series in the transverse direction of the tunnel and installed in the invert section 33 while maintaining gaps 21a, 21b between the receiving base portion 31c at the lower end of the adjacent side wall lining body 31a and between the adjacent PCa concrete blocks 20A, 20B, 20C, and also maintaining gaps 21b between the adjacent PCa concrete blocks 20A, 20B, 20C in the axial direction of the tunnel. A process is carried out in which the PCa concrete blocks 20A, 20B, 20C of the one-side block group 20X are arranged in a row and installed in the invert portion 33 while held in that state, thereby forming the one-side block group 20X, and a process is carried out in which the filling solidification material 22 is filled and solidified in the gaps 21a between adjacent receiving base portions 31c of the multiple PCa concrete blocks 20A, 20B, 20C of the one-side block group 20X arranged in a row vertically and horizontally, the gaps 21b between adjacent PCa concrete blocks 20A, 20B, 20C, and the gaps 20c below the hexahedral underside portions communicating with these, thereby forming the one-side invert portion structure 10X.

[0028] Thereafter, in the other side region 55Y in the transverse direction of the tunnel, a plurality of PCa concrete blocks 20A, 20B, 20C are arranged in series in the transverse direction of the tunnel, with gaps 21a, 21b maintained between the receiving base 31c at the lower end of the adjacent side wall lining body 31a and between the adjacent PCa concrete blocks 20A, 20B, 20C, and are installed in the invert section 33. Also, in the axial direction of the tunnel, the adjacent PCa concrete blocks 20A, 20B, 20C are arranged in series, with gaps 21b maintained between the adjacent PCa concrete blocks 20A, 20B, 20C, and are installed in the invert section 33. 33 to form the other-side block group 20Y, and filling and solidifying the filling solidification material 22 into the gaps 21a between the adjacent receiving bases 31c of the multiple PCa concrete blocks 20A, 20B, 20C of the other-side block group 20Y arranged vertically and horizontally, the gaps between the adjacent PCa concrete blocks 20A, 20B, 20C, and the gaps 21c below the hexahedral undersides communicating with these, as well as into the gaps 51 between the one-side block group 20X and the other-side block group 20Y, to form the other-side invert structure 10Y.

[0029] As a result, the one side invert structure 10X and the other side invert structure 10Y can be integrated to form an invert lining body 32 that is installed over the entire transverse area of ​​the tunnel in the invert section 33, and the formed invert lining body 32 can be further integrated with the existing tunnel lining body 31 in the area from the side wall portion 31a to the upper arch-shaped portion 31b, making it possible to form a strong lining body that is continuously closed in a curved ring shape as an annular support structure.

[0030] In addition, in this embodiment, similar to the construction method of the invert structure of Patent Application No. 2023-058346, the invert structure 10X, 10Y using PCa concrete blocks 20 that constitute the invert covering body 32 is constructed separately for each of the one-side regions 55X, 55Y on both sides of the center in the transverse direction, so that each is formed on one side in each one-side region while ensuring passage in the other one-side region of each.

[0031] That is, as shown in Fig. 1 to Fig. 3, in the center of the transverse direction of the tunnel 30 in the invert section 33, a plurality of H-shaped steels 35 supporting an earth retaining plate member 57 are installed by driving them into the ground of the invert section 33 with a predetermined interval in the axial direction of the tunnel 30 and with the flange portion 35a arranged along the axial direction of the tunnel. By supporting the earth retaining plate member 57 on the flange portion 35a on one side region 55X side or the flange portion 35a on the other side region 55Y side of the erected H-shaped steel 35, the foundation base plate 61 (see Fig. 3) in the other side region 55Y is retained, and in a state where the passageway 60 in the other side region 55Y is secured, the foundation base plate 61 in one side region 55X is excavated, and the one-side invert section structure 10X can be formed in the one side region 55X using PCa concrete blocks 20 and filled solidification material 22.

[0032] In addition, after forming the one-side invert structure 10X in one side region 55X, the ground to be backfilled as a roadbed in the upper part of the formed one-side invert structure 10X is retained by supporting the H-shaped steel 35 with the retaining plate member 57, and the passageway in one side region 55X is restored.In the other side region 55Y, the foundation base 61 of the other side region 55Y is excavated, whereby the remaining other-side invert structure 10Y can be formed using PCa concrete blocks 20 and filling solidification material 22, and this makes it possible to form an invert lining body 32 spanning the entire transverse width of the tunnel 30.

[0033] In this embodiment, as described above, when forming one-side block group 20X by arranging multiple PCa concrete blocks 20 vertically and horizontally in a row in one transverse side region 55X of tunnel 30 prior to the other transverse side region 55Y (see Figures 4 and 5), as shown in Figure 6, at least one row of block rows 20Z arranged in a row in the transverse direction of tunnel 30 is formed by filling and solidifying filling solidification material 22 in the gaps 21a between adjacent receiving base portions 31c of one row of block rows 20Z, the gaps 21b between adjacent PCa concrete blocks 20, and the interval portions 63 between the end face portions 61a of the foundation base plate 61 of the other side region 55Y, thereby forming a first closing portion covering body 65 that is continuous in a ring shape as a single unit in the circumferential direction in the at least one row of block rows 20Z.

[0034] As a result, after excavating the foundation base 61 in one side region 55X, it is possible to quickly obtain the first closed portion lining 65, which is continuously closed in a ring shape as a whole in the circumferential direction, by a structure made of a row of blocks 20Z formed in advance, without waiting for the one side structure 10X and the other side structure 10Y to be integrated to form the invert portion lining 32.This makes it possible to effectively prevent the existing tunnel lining 31 in the area from both side wall portions 31a to the upper arch-shaped portion 31b from becoming easily deformed until the one side structure 10X and the other side structure 10Y are integrated.

[0035] In this embodiment, as described above, for example, after the step of forming the first closing portion covering body 65, when forming the other side block group 20Y by arranging a plurality of PCa concrete blocks 20 vertically and horizontally in series in the other side region 55Y in the transverse direction of the tunnel 30 following the one side block group 20X of one side region 55X (see Figures 1 and 2), as shown in Figure 7, as at least one row of block rows 20Z' arranged in series in the transverse direction of the tunnel 30, one row of block rows 20Z' is arranged adjacent to the adjacent block rows 20Z'. By filling and solidifying the filling solidification material 22 into the gap 21a between the receiving base portion 31c and the adjacent PCa concrete block 20, the gap 21b between the adjacent PCa concrete block 20, and the gap portion 64 between the end face portion 10Xa on the other side region 55Y side of the one-side structure 10X made of the one-side block group 20X formed prior to one of the one-side regions 55X, a second closing portion covering body 66 that is continuous in a ring shape as a single unit in the circumferential direction is formed in at least one block row 20Z'.

[0036] As a result, after excavating the foundation base 61 in the other side region 55Y, it is possible to quickly obtain the second closing portion lining 66, which is continuous in a ring shape and integrated in the circumferential direction, by a structure made of a row of blocks 20Z' formed in advance, without waiting for the one side structure 10X and the other side structure 10Y to be integrated to form the invert portion lining 32.This makes it possible to effectively prevent the existing tunnel lining 31 in the region from both side wall portions 31a to the upper arch-shaped portion 31b from becoming easily deformed until the one side structure 10X and the other side structure 10Y are integrated.

[0037] Therefore, according to the construction method of the invert structure of this embodiment, from the time when the foundation base 61 is excavated in one side region 55X or the other side region 55Y of the mountain tunnel, until the one side invert structure 10X of one side region 55X and the other side invert structure 10Y of the other side region 55Y are integrated and the lining is closed, it is possible to effectively prevent the existing tunnel lining 31 from becoming prone to deformation in a stable state, and it is also possible to effectively prevent the resulting impact on the surrounding ground.

[0038] Furthermore, according to the construction method of the invert structure of this embodiment, as described above, displacement measuring devices 67 (see Figures 6 and 7) are attached, for example at predetermined intervals in the axial direction of the tunnel 30, to a plurality of predetermined positions of the existing tunnel lining 31, preferably in the area extending from both side wall portions 31a to the upper arch-shaped portion 31b, and in the process of forming the above-mentioned first closing portion lining 65 or the process of forming the above-mentioned second closing portion lining 66, the first closing portion lining 65 or the second closing portion lining 66, which is continuous in a ring shape as a single unit in the circumferential direction, is formed in at least one row of block rows 20Z, 20Z' arranged adjacent to the position where the displacement measuring device 67 where the displacement is measured is attached, in the portion of at least one row of block rows 20Z, 20Z' arranged adjacent to the transverse direction of the tunnel.

[0039] This allows the parts of the existing tunnel lining 31 that are prone to deformation due to the influence of the geology of the surrounding ground, etc. to be detected in real time, and the first closing portion lining 65 and the second closing portion lining 66 are formed preferentially in those parts, making it possible to more quickly prevent the existing tunnel lining 31 from becoming prone to deformation, and

[0040] The present invention is not limited to the above embodiment and can be modified in various ways. For example, the first closing part lining body and the second closing part lining body do not necessarily have to be formed only in one block row as at least one block row connected in the transverse direction of the tunnel, but may be formed across two or more block rows. [Explanation of symbols]

[0041] 10X One side inverter structure 10Xa end face part 10Y Other side inverter structure 20 PCa concrete blocks 20a Top part 20b Bottom part 20A Receiving block 20B Center side block 20C Middle block 20X One-sided block group 20Y Other side block group 20Z,20Z' Block row 21a Gap between the support and the base 21b Gaps between adjacent PCa concrete blocks 21c Lower gap of the bottom surface 22 Filling and solidification materials 23 Bolt Box 24 Female thread anchor 30 Mountain Tunnel 30a Bottom panel part 31 Existing tunnel lining 31a Side wall (side wall lining) 31b Arch-shaped part 31c pedestal part 32 Invert section lining 33 Inverter 35 H type steel 35a Flange part 51 Interval between one side block group and the other side block group 55X One side area 55Y Other unilateral area 57 Earth retaining plate material 60 Passage route 61 Foundation bottom plate 61a End section 63,64 Interval part 65 First closing part lining 66 Second closing part lining 67 Displacement Measuring Instruments C Transverse centre line of the tunnel

Claims

1. A construction method for an invert structure using PCa concrete blocks, which constitutes an invert lining provided in an invert section of a mountain tunnel, The PCa concrete block is formed as a hexahedral block having curved upper and lower surfaces so as to have a curved shape along the cross-sectional shape of the invert section covering body, In each of one side region and the other side region in the transverse direction of the tunnel, the multiple PCa concrete blocks are arranged in a row in the transverse direction of the tunnel and installed in the invert portion, with gaps maintained between the support portions of the lower ends of the adjacent side wall lining bodies and between the adjacent PCa concrete blocks, and also in the axial direction of the tunnel, with gaps maintained between the adjacent PCa concrete blocks, thereby forming a one-side block group and an other-side block group. In each of the one-side block group and the other-side block group, the multiple PCa concrete blocks arranged in a row in the vertical and horizontal directions are integrated through the filled solidification material by filling and solidifying the gaps between the adjacent support portions, the gaps between the adjacent PCa concrete blocks, the intervals between the one-side block group and the other-side block group, and the gaps below the lower surface of the hexahedron communicating with these gaps and intervals, thereby forming the invert portion lining. A construction method for an invert section structure, comprising: forming the one-side block group by arranging a plurality of the PCa concrete blocks vertically and horizontally in a row in one transverse side region of the tunnel prior to the other transverse side region; filling and solidifying a filling solidification material in the gaps between adjacent support portions, the gaps between adjacent PCa concrete blocks, and the gaps between the end face portion of the foundation base plate of the other side region of at least one row of blocks arranged in a row in the transverse direction of the tunnel, thereby forming a first closing portion covering body that is continuous in a ring shape as a single unit in the circumferential direction in the at least one row of block rows.

2. A construction method for an invert structure using PCa concrete blocks, which constitutes an invert lining provided in an invert section of a mountain tunnel, The PCa concrete block is formed as a hexahedral block having curved upper and lower surfaces so as to have a curved shape along the cross-sectional shape of the invert section covering body, In each of one side region and the other side region in the transverse direction of the tunnel, the multiple PCa concrete blocks are arranged in a row in the transverse direction of the tunnel and installed in the invert portion, with gaps maintained between the support portions of the lower ends of the adjacent side wall lining bodies and between the adjacent PCa concrete blocks, and also in the axial direction of the tunnel, with gaps maintained between the adjacent PCa concrete blocks, thereby forming a one-side block group and an other-side block group. In each of the one-side block group and the other-side block group, the multiple PCa concrete blocks arranged in a row in the vertical and horizontal directions are integrated through the filled solidification material by filling and solidifying the gaps between the adjacent support portions, the gaps between the adjacent PCa concrete blocks, the intervals between the one-side block group and the other-side block group, and the gaps below the lower surface of the hexahedron communicating with these gaps and intervals, thereby forming the invert portion lining. a second closing portion covering body that is continuous in a ring shape in the circumferential direction of the at least one block row by filling and solidifying a filling solidification material in the gaps between adjacent support portions, the gaps between adjacent PCa concrete blocks, and the gaps between the end face portions of the one-side structure formed prior to the one-side region in the one-side region in the other transverse direction of the tunnel, in order to form the other-side block group by arranging a plurality of the PCa concrete blocks vertically and horizontally in a row in the other transverse direction of the tunnel following the one-side region, thereby forming a second closing portion covering body that is continuous in a ring shape as a single unit in the circumferential direction in the at least one block row portion.

3. A construction method for an invert structure as described in claim 1 or 2, wherein displacement measuring devices are attached to multiple predetermined positions of an existing tunnel lining, and in the process of forming the first closing portion lining or the process of forming the second closing portion lining, the first closing portion lining or the second closing portion lining is formed in a circumferentially integral, annular manner in at least one row of blocks connected in the transverse direction of the tunnel, adjacent to the position where the displacement measuring device where the displacement is measured is attached.

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