Construction method for invert section structure

Abstract

To provide a construction method for an invert section structure, capable of efficiently excavating the ground of an invert section using few heavy machines and laying a large number of PCa concrete blocks in a row vertically and horizontally.SOLUTION: The invert section structure is configured including an excavation and laying step of excavating the ground 61 of an invert section 33 and laying PCa concrete blocks 20. In an excavation step, the ground 61 of the invert section 33 is excavated with an excavation width W in which two rows of block rows 20D can be installed by a back-forger 76 arranged on the ground 61 on the front side in a laying direction X. In a laying step, the PCa concrete blocks 20 transported by passing over the PCa concrete blocks 20 installed in advance are lifted by the back-forger 76 facing in the same direction as in the excavation step, and are laid on an excavated base plate section 61b.SELECTED DRAWING: Figure 7

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 inner wall surface of the excavated tunnel is covered with a primary lining and a secondary lining made of concrete or mortar. That is, after the inner wall surface of the mountain tunnel is excavated while performing, for example, blasting, etc., a protective layer is formed on the inner wall surface of the mountain tunnel by spraying mortar or concrete, and then, for example, a known tunnel lining formwork is installed inside the protective layer formed by the primary lining, and a main body lining body made of concrete with a predetermined thickness is formed as a secondary lining from the side wall portion to the upper arch-shaped portion of the tunnel. Furthermore, the ground is excavated in the portion between the support portions at the lower ends of the pair of side walls of the main body lining body extending from the side walls on both sides of the tunnel formed previously to the upper arch-shaped portion, and a lining body of the bottom invert part is formed integrally with concrete with a predetermined thickness in the transverse direction of the tunnel on the excavated base plate part, so that the entire circumference of the inner wall surface of the mountain tunnel is continuously covered in a ring shape by the secondary lining.

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

[0004] Conventionally, the use of cast-in-place concrete has been considered as a method for forming an invert lining at the bottom of a tunnel, continuous with the main body lining that is installed prior to the tunnel from the side wall to the upper arch-shaped portion (see, for example, Patent Document 1). However, when cast-in-place concrete is used, it takes a considerable amount of time for the poured concrete to harden and undergo the specified curing period. Therefore, particularly when a new invert lining is formed on the main body lining from the side wall to the upper arch-shaped portion, omitting the invert lining, this will result in traffic inside the tunnel being blocked for a long period of time, so it is desirable to complete the construction work in a shorter period of time.

[0005] For this reason, the applicant of the present application has disclosed, for example, in Patent Application No. 2023-58334, an invert section structure that enables an invert section covering body to be formed efficiently and easily by using a PCa concrete block made of a hexahedral block having curved upper and lower surfaces, which have a curved shape that follows the cross-sectional shape of the invert section covering body.

[0006] In the invert section structure described in Patent Application No. 2023-58334, multiple hexahedral PCa concrete blocks are arranged vertically and horizontally in the transverse and axial directions of the tunnel, with gaps maintained between adjacent support bases and between adjacent PCa concrete blocks, and are installed in the invert section.These vertically and horizontally arranged PCa concrete blocks are integrated together via a filling solidification material that is filled in the gaps between adjacent support bases, the gaps between adjacent PCa concrete blocks, and the gaps below their undersides, to form the invert section covering body 32. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2020-159060 A Summary of the Invention [Problem to be solved by the invention]

[0008] On the other hand, in the invert structure described in Patent Application No. 2023-58334, prior to filling with the filling solidification material, the ground of the invert section is excavated, and after excavation, a large number of PCa concrete blocks are laid in a predetermined position on the leveled base, arranged vertically and horizontally. However, since the work of laying and installing such a large number of PCa concrete blocks in a row and vertically is carried out in a narrow space inside the main body covering body, from the side walls on both sides of the tunnel to the arch-shaped part at the top, it is desirable to use as few heavy machinery as possible to efficiently lay the blocks while avoiding tangling of the heavy machinery with each other.

[0009] In addition, when the ground of the invert is excavated in the region between the lower ends of both sides of the main body lining that is provided in advance of the arch-shaped portion from the side wall of the tunnel to the upper part, the annular support structure that is curved in a cross section and continuous in a ring shape, which was formed integrally with the existing main body lining of the arch-shaped portion from the side wall of the tunnel to the upper part and the ground of the invert, becomes discontinuous in the ground of the excavated invert part, and if this state in which the annular support structure of the existing main body lining and the ground of the invert part are discontinuous continues for a considerable period of time, depending on the geology of the surrounding ground, for example, the existing main body lining may deform and affect the surrounding ground. For this reason, it is desired to develop a construction method that eliminates the state in which the annular support structure including the main body lining is discontinuous in the excavated invert part and enables the annular support structure to be closed early.

[0010] The present invention aims to provide a construction method for an invert structure that can efficiently excavate the ground in the invert section using as few heavy machinery as possible in the inner area of ​​the main body covering body extending from the side walls on both sides of the tunnel to the upper arch-shaped portion, and can lay a large number of PCa concrete blocks in predetermined positions by connecting them vertically and horizontally.

[0011] In addition, the present invention aims to provide a construction method for an invert structure that can quickly close the state in which the annular support structure including the main body covering body is discontinuous in the excavated invert section, thereby effectively avoiding the impact on the ground around the existing main body covering body. [Means for solving the problem]

[0012] The present invention is 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 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. The invert structure is configured such that 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 parts of the lower ends of adjacent main body linings and between adjacent PCa concrete blocks, and are also arranged in series vertically and horizontally and installed in the invert section, with gaps maintained between adjacent PCa concrete blocks in the axial direction of the tunnel, and the plurality of PCa concrete blocks arranged in series vertically and horizontally are integrated via a filling solidification material that is filled and solidified in the gaps between adjacent support parts, the gaps between adjacent PCa concrete blocks, and the gaps below the lower surface of the hexahedron that communicate with these gaps. The invert section lining is constructed by the above-mentioned construction, and the invert section structure is constructed by excavating the ground of the invert section in the region between the lower ends of both sides of the main section lining, which is provided preceding the arch-shaped portion at the top from the side wall of the tunnel, and laying a plurality of the PCa concrete blocks in a row vertically and horizontally on the leveled base plate. In the excavation and laying process, the PCa concrete blocks are laid on the ground of the invert section on the front side of the laying direction in the axial direction of the tunnel, facing the rear side of the laying direction. an excavation process in which the excavation and lifting heavy machinery is used to excavate the ground of the invert section with a predetermined excavation width in the axial direction of the tunnel in which one or more rows of blocks formed by consecutively laying the PCa concrete blocks in the transverse direction of the tunnel can be installed, while moving the excavation and lifting heavy machinery to the front side in the laying direction using the excavation and lifting heavy machinery that has been arranged in advance; and a newly installed PCa concrete block that has been transported from the rear side to the front side in the laying direction in the axial direction of the tunnel by passing over the PCa concrete blocks that have been laid and installed in advance.The above object has been achieved by providing a construction method for an invert section structure in which the invert section is hoisted by the excavation and lifting heavy machine arranged on the ground of the front side of the invert section, and then hoisted into a predetermined position on the base plate section that has been leveled to a predetermined excavation width after being excavated in the excavation process, and then laid out and installed.

[0013] Furthermore, in the construction method of the invert section structure of the present invention, it is preferable that the specified excavation width for excavating the ground of the invert section using the excavation and lifting heavy equipment is the axial width of a tunnel in which one or two rows of blocks can be installed.

[0014] Furthermore, in the construction method of the invert structure of the present invention, a tunnel is excavated in the axial direction of the tunnel to the specified excavation width, which allows the installation of one or two rows of blocks, and a plurality of the PCa concrete blocks are laid out in one or two rows in a continuous arrangement on the leveled base plate. It is also preferable that the PCa concrete blocks of the one or two rows of blocks are integrated by filling and solidifying a filling solidification material into the gaps between adjacent support parts, the gaps between adjacent PCa concrete blocks, and the gaps below the hexahedral underside part that communicates with these gaps, for each of the laid out rows of blocks.

[0015] Furthermore, in the construction method of the invert structure of the present invention, it is preferable that the excavation and lifting heavy machinery is a backhoe.

[0016] Furthermore, in the construction method of the invert section structure of the present invention, it is preferable that, in the laying step of the excavation and laying process, the newly installed PCa concrete block is placed on a guide rail laid on top of the row of blocks that have been laid in advance, and is transported from the rear to the front in the laying direction.

[0017] In addition, in the construction method of the invert section structure of the present invention, it is preferable that, in the laying step of the excavation and laying process, the newly installed PCa concrete block is placed on a transport cart that can run over the row of blocks that have been laid and installed previously, and is transported from the rear to the front in the laying direction.

[0018] Furthermore, in the construction method of the invert section structure of the present invention, it is preferable that, in the laying step of the excavation and laying step, the newly installed PCa concrete blocks are supplied onto the block row from the rear side in the laying direction in the axial direction of the tunnel using a block lifting lifting machine positioned on the ground of the invert section rear of the block row made of the PCa concrete blocks previously laid and installed.

[0019] Furthermore, in the construction method of the invert structure of the present invention, it is preferable that the multiple PCa concrete blocks arranged vertically and horizontally are installed in the invert section in a potato-like arrangement in which the gaps between adjacent PCa concrete blocks in the transverse direction of the tunnel and the gaps between adjacent PCa concrete blocks in the axial direction of the tunnel are all continuous in a straight line. Effect of the Invention

[0020] According to the construction method of the invert structure of the present invention, in the inner area of ​​the main body covering body extending from the side walls on both sides of the tunnel to the upper arch-shaped portion, the ground of the invert section can be excavated efficiently using as little heavy machinery as possible, and a large number of PCa concrete blocks can be arranged vertically and horizontally in a row and laid in predetermined positions.

[0021] In addition, for one or two rows of blocks that are excavated at a specified excavation width in the axial direction of the tunnel and laid on the leveled base, the gaps between adjacent support sections, the gaps between adjacent PCa concrete blocks, and the gaps below the underside are filled with filling solidification material and solidified, thereby integrating the PCa concrete blocks of these one or two rows of blocks.This makes it possible to quickly close the state in which the annular support structure including the main body lining is discontinuous in the excavated invert section, and effectively avoids the ground around the existing main body lining from being affected. [Brief description of the drawings]

[0022] [Figure 1] 1A and 1B are schematic cross-sectional views and a schematic plan view illustrating a temporary installation for installing invert blocks in which a construction method for an invert structure according to a preferred embodiment of the present invention is carried out. [Diagram 2] This is a simplified cross-sectional view illustrating a mountain tunnel in which invert structures are formed on both sides of the invert in the transverse direction of the tunnel. [Diagram 3] This is a schematic top view seen from the AA direction in Figure 2, illustrating the state in which the invert section structure is formed on both sides over the entire area of ​​the invert section in the transverse direction of the tunnel. [Figure 4] This is a schematic cross-sectional view of a mountain tunnel that illustrates the state in which PCa concrete blocks are laid in one side area while allowing vehicles to pass in the other side area. [Diagram 5] FIG. 13 is a plan view of a main portion illustrating temporary equipment when installing inverter blocks. [Figure 6] FIG. 11 is a longitudinal cross-sectional view of a main portion illustrating a temporary facility when an inverter block is installed. [Figure 7] 1(a) to 1(e) are schematic vertical cross-sectional views illustrating a method for constructing an invert structure according to a preferred embodiment of the present invention. [Figure 8] This is a schematic top view of an invert structure provided in one side region in the transverse direction of the tunnel. [Figure 9] 9 is a schematic cross-sectional view taken along the line CC in FIG. 8 before the filling solidification material is filled. [Figure 10] This is an oblique view of the PCa concrete block that constitutes the invert structure. [Figure 11] (a) is a top view of the PCa concrete block that constitutes the invert structure, (b) is a transverse side view of (a) seen from the right side, and (c) is an axial side view of (a) seen from the front. [Figure 12] 2 is a schematic cross-sectional view illustrating a PCa concrete block along a portion in which a bolt insertion hole is formed, illustrating the bolt insertion hole. FIG. [Figure 13] This is a simplified cross-sectional view illustrating the state in which filling solidification material has been filled into the gaps between the receiving base, the gaps between adjacent PCa concrete blocks, and the gaps below the bottom surface of the hexahedral shape. [Figure 14] 2 is a schematic cross-sectional view in the transverse direction of a PCa concrete block along a portion where a filler injection hole is formed, illustrating a filler injection hole and an opening and closing valve. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] A construction method for an invert structure according to a preferred embodiment of the present invention is used as a method for forming an invert lining 32 on the bottom portion 30a of a mountain tunnel 30, for example, in an existing mountain tunnel 30 shown in FIG. 2, in such a manner that the invert lining 32 is continuous with the main body lining 31 in the region 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, and preferably when forming the invert structures 10 on both left and right sides, which are components of the invert lining 32, on either side of the center line C in the transverse direction of the tunnel, the invert structures 10 are efficiently laid vertically and horizontally, i.e., PCa concrete blocks 20, which are hexahedral invert blocks that form the invert structure 10, in the inner region of the main body lining 31 that has been formed in advance, and preferably the annular support structure including the main body lining 31, can be closed early.

[0024] 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 covering the inner wall surface of the tunnel was only the main body lining 31 extending 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, so a new invert lining 32 is formed using invert structures 10 on both the left and right sides, as shown in Figure 3.

[0025] Furthermore, 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 passage on the passageway, without completely blocking traffic through the tunnel. In this embodiment, as shown in Fig. 4, each step of forming the invert structure 10 is carried out in one side region 55A while securing passage on the passageway 60 in the other side region 55B in the transverse direction of the tunnel. In addition, in the construction method of the invert structure of this embodiment, a temporary facility 70 (see Figure 1) for installing the invert blocks, which will be described later, is preferably provided in one of the transverse side regions 55A of the multi-lane road tunnel 30, so that when the invert structure 10 that constitutes the invert lining body 32 is formed by integrating a plurality of hexahedral PCa concrete blocks 20, these plurality of hexahedral PCa concrete blocks 20 can be efficiently installed in a row and connected vertically and horizontally in the inner region of the main body lining body 31, which is a narrow space, while excavating the ground 61 of the invert 33, using as little heavy machinery as possible.

[0026] Furthermore, in this embodiment, in the temporary installation equipment 70 provided in one side area 55A, a large number (multiple) PCa concrete blocks 20 can be efficiently installed in a row and columns without affecting vehicle traffic in the other side area 55B.

[0027] Furthermore, when the ground 61 (see Figure 4) of the invert section 33 is excavated in the region between the lower end portions on both sides of the previously installed main body covering body 31, the annular support structure which was formed integrally with the main body covering body 31 and the ground 61 of the invert section 33 and which is continuous in a circular shape in cross section becomes discontinuous in the excavated part of the ground 61 of the invert section 33. However, in this embodiment, it is preferable to eliminate this discontinuous state in the excavated part of the invert section 33, so that the annular support structure including the main body covering body 31 can be closed early.

[0028] The construction method of the invert structure of this embodiment is a construction method for forming an invert structure using a PCa concrete block 20 that constitutes the invert lining 32 to be provided in the invert 33 of a mountain tunnel 30, and the PCa concrete block 20 is formed as a hexahedral block having curved upper surface 20a and lower surface 20b so as to have a curved shape that follows the cross-sectional shape of the invert lining 32, as shown in Figures 8 to 11(a) to (c). As shown in FIG. 2 and FIG. 3, the invert structure 10 is arranged in a row in the transverse direction of the tunnel 30 and installed in the invert section 33, with gaps 21a and 21b maintained between the receiving base 31c at the lower end of the adjacent main body covering body 31 and between the adjacent PCa concrete blocks 20, and is also arranged in a row vertically and horizontally in the axial direction of the tunnel and installed in the invert section 33, with gaps 21b maintained between the adjacent PCa concrete blocks 20. The multiple PCa concrete blocks 20 arranged in a row vertically and horizontally are filled and solidified in the gaps 21a between the adjacent receiving bases 31c, the gaps 21b between the adjacent PCa concrete blocks 20, and the gaps 21c below the hexahedral lower surface 20b communicating with these gaps 21a and 21b, and are integrated through the filling solidification material 22 (see FIG. 13) to form the invert covering body 32. The invert structure 10 is constructed by excavating the ground 61 (see Figure 4) of the invert section 33 in the region between the lower ends of both sides of the main body covering body 31, which is installed preceding the side wall portion 31a of the tunnel 30 to the upper arch-shaped portion 31b, and laying a plurality of PCa concrete blocks 20 in a vertical and horizontal order in a row on the leveled base portion 61a (see Figures 7(a) to (e)).

[0029] In the excavation and laying process, as shown in Figs. 7(a) to (e), a heavy excavation and lifting machine 76 is placed on the ground 61 of the invert section 33 on the front side of the laying direction X in the axial direction of the tunnel 30, facing the rear side of the laying direction X. While moving the heavy excavation and lifting machine 76 forward in the laying direction X, the ground 61 of the invert section 33 is excavated by the heavy excavation and lifting machine 76 with a predetermined excavation width W (see Fig. 7(c)) in the axial direction of the tunnel in which one or more block rows 20D formed by consecutively laying PCa concrete blocks 20 in the transverse direction Y of the tunnel 30 can be installed. An excavation process (see Figures 7(a) to (c)) and a laying process (see Figures 7(c) and (d)) are carried out in which the newly installed PCa concrete blocks 20, which have been transported from the rear side to the front side in the laying direction X in the axial direction of the tunnel, are passed over the PCa concrete blocks 20 that have been laid and installed previously, and are then lifted by an excavation and hoisting heavy machine 76 positioned on the ground 61 of the forward invert section 33, and hoisted into a predetermined position on the base plate section 61b that has been leveled to a predetermined excavation width W after being excavated in the excavation process, thereby laying and installing the newly installed PCa concrete blocks 20 side by side.

[0030] In addition, in this embodiment, the specified excavation width W used to excavate the ground 61 of the invert section 33 by the excavation and hoisting heavy equipment 76 is preferably the axial width of the tunnel in which one or two rows of blocks 20D can be installed. The ground 61 of the invert section 33 is excavated for each predetermined excavation width W in the axial direction of the tunnel, preferably so that one or two rows of block rows 20D can be installed, and a plurality of PCa concrete blocks 20 are laid out in one or two rows in a continuous arrangement on the leveled base section 61b. For each of the laid out rows of block rows 20D, the gaps 21a between adjacent receiving sections 31c, the gaps 21b between adjacent PCa concrete blocks 20, and the gaps 21c below the hexahedral lower surface section 20b that communicate with these gaps are filled with filling solidification material 22 and solidified, so that the PCa concrete blocks 20 of the one or two rows of block rows 20D are integrated together (see Figure 7(e)).

[0031] Furthermore, in this embodiment, in the laying step of the excavation and laying process, the newly installed PCa concrete block 20 is preferably placed on a guide rail 77 laid on top of the block row 20D that has been laid and installed previously, as shown in Figures 5 and 6, and is transported from the rear to the front in the laying direction X.

[0032] Furthermore, in this embodiment, in the laying step of the excavation and laying process, the newly installed PCa concrete blocks 20 are preferably supplied onto the block row 20D made of the PCa concrete blocks 20 laid and installed previously from the rear side in the laying direction X in the axial direction of the tunnel using a block lifting lifting machine 74 arranged on the ground 61 of the invert section 33 on the rear side in the laying direction X of the block row 20D, as shown in Figures 1(a) and (b).

[0033] In this embodiment, as described above, while ensuring passage on the passageway 60 of the other side area 55B in the transverse direction Y of the tunnel, each process of forming the invert section structure 10 is carried out in the temporary facility 70 for arranging the invert block provided in one side area 55A as shown in Figures 1 (a) and (b). The temporary facility 70 for arranging the invert block preferably has a configuration similar to that of the temporary facility for arranging described in Japanese Patent Application No. 2023-58440, and as shown in Figures 5 and 6, in the work yard 71 of one side area 55A, in the ground 61 of the invert section 33 in the laying area 72 where the PCa concrete blocks 20 are laid, a backhoe is preferably movably installed as an excavation lifting heavy machine 76 in a space 75 on the side of the laying end portion 72c forward of the laying start end portion 72b in the laying direction X.

[0034] In addition, in this embodiment, a block lifting lifting machine 74, preferably consisting of a crawler crane, is movably installed in a space 73 in the ground 61 of the invert section 33 of the work yard 71 in one side area 55A, rearward of the laying starting end 72b of the laying area 72 in the laying direction X.

[0035] Furthermore, in this embodiment, a block transport conveyor device 77 is provided as a guide rail on the upper surface of the block row 20D of the PCa concrete blocks 20 that are sequentially installed in the laying area 72 from the laying start end 72b toward the front laying end 72c, and extends from the laying start end 72b to an area within the working radius of the excavation and lifting heavy machine 76. The block transport conveyor device 77 is preferably provided so as to be able to be added in the laying direction X as the PCa concrete blocks 20 are sequentially installed in the laying direction X from the laying start end 72b toward the laying end 72c.

[0036] Furthermore, in this embodiment, preferably in the work yard 71 of the one-side region 55A, in the space 73 on the rear side of the laying start end 72b of the laying region 72 in the laying direction X, an auxiliary block lifting lifting machine 78 is movably installed at a distance further rearward from the block lifting lifting machine 74, and an auxiliary block transport conveyor device 79 is disposed extending from the area within the working radius of the auxiliary block lifting lifting machine 78 to the area within the working radius of the block lifting lifting machine 74. Also, preferably in the work yard 71 of the one-side region 55A, in the space on the rear side of the auxiliary block lifting lifting machine 78 in the laying direction X, a truck, which is a transport vehicle 80 loaded with PCa concrete blocks 20, moves in the laying direction X with its loading platform facing forward in the laying direction X.

[0037] In this embodiment, the invert structure 10 formed in one side region 55A and the other side region 55B is formed by arranging a plurality of PCa concrete blocks 20 in series in the transverse direction of the tunnel and installing them in the invert section 33 while maintaining gaps 21a, 21b between the receiving base portions 31c at the lower ends of adjacent side wall portions 31a and between adjacent PCa concrete blocks 20, as shown in Figures 8 and 9, and by arranging a plurality of PCa concrete blocks 20 in series in the transverse direction of the tunnel and installing them in the invert section 33 while maintaining gaps 21b between adjacent PCa concrete blocks 20 in the axial direction of the tunnel as well. The blocks 20X, 20Y are integrated together via the solidified filling solidification material 22 by filling the gaps 21a between adjacent receiving base portions 31c and the gaps 21b between adjacent PCa concrete blocks 21b with filling solidification material 22 (see Figure 13).

[0038] That is, in this embodiment, the invert structure 10 is provided in at least one side region in the cross-sectional direction of the invert 33 of the mountain tunnel 30, and is a structure of the invert 33 using PCa concrete blocks 20 that constitute the invert lining body 32. As shown in FIG. 10 and FIG. 11(a) to (c), the PCa concrete blocks 20 are formed as hexahedral blocks having curved upper surface portions 20a and lower surface portions 20b so as to have a curved shape along the cross-sectional shape of the invert lining body 32. These multiple PCa concrete blocks 20 are arranged in series in the cross-sectional direction of the tunnel and installed in the invert 33 with 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 20, and are also arranged in series in the axial direction of the tunnel with gaps 21b between the adjacent PCa concrete blocks. These multiple PCa concrete blocks 20 arranged vertically and horizontally in succession are integrated through filling solidification material 22 that has been filled and solidified in the gaps 21a between adjacent receiving base portions 31c, the gaps 21b between adjacent PCa concrete blocks 20, and the gaps 21c below the hexahedral underside portion connecting to these gaps 21a, 21b, as shown in Figures 2, 3, and 13, and constitute one side portion of the invert covering body 32 as at least a part of the invert covering body 32.

[0039] In this embodiment, the PCa concrete blocks 20 are preferably formed to have a similar hexahedral shape with the same width x in the transverse direction of the tunnel, the same vertical width y in the axial direction of the tunnel, and the same height z (see FIG. 10 and FIG. 11(a) to (c)). The PCa concrete blocks 20 arranged in a row are arranged in a row and horizontally, and the gaps 21b extending in the axial direction between the PCa concrete blocks 20 adjacent to each other in the transverse direction of the tunnel, filled with the filling solidification material 22, and the gaps 21b extending in the transverse direction between the PCa concrete blocks 20 adjacent to each other in the axial direction of the tunnel, are preferably arranged in a potato shape that is linearly continuous, and are installed in the invert part 33 (see FIG. 3 and FIG. 8). The gaps 21a between the adjacent receiving base parts 31c filled with the filling solidification material 22 and the gaps 21b between the adjacent PC concrete blocks are preferably gaps with an interval width of about 15 to 30 mm.

[0040] Furthermore, in this embodiment, the PCa concrete blocks 20 are embedded and fixed to the four sides of the upper surface portion of each hexahedron shape with bolt boxes 23 or female screw anchors 24 for connecting adjacent PCa concrete blocks 20 using bolt members (not shown). The bolt boxes 23 open on the upper surface portion 20a of the PCa concrete block 20, and the female screw anchors 24 open on the upper end portions of the axially facing surface 20c and the transversely facing surface 20d of the side portion. As shown in FIG. 12, the PCa concrete block 20 has three bolt insertion screw holes 25 that penetrate the hexahedron shape in the vertical direction and are arranged at each corner of the isosceles triangle (see FIG. 11(a)). A female screw member 25a into which a height adjustment bolt 26 is screwed is fixed to each bolt insertion screw hole 25 at a portion lower than the vertical middle portion. A large trumpet-shaped recess 25b is formed from the portion where the female screw member 25a of each bolt insertion screw hole 25 is fixed, expanding in diameter upward and opening on the upper surface 20a of the PCa concrete block 20, and a small trumpet-shaped recess 25c is formed from the portion where the female screw member 25a is fixed, expanding in diameter downward and opening on the lower surface 20b of the PCa concrete block 20. A height adjustment bolt 26 is inserted into each of these bolt insertion screw holes 25 and screwed into the female screw member 25a, so that the height adjustment bolt 26 is attached with its lower end portion 26a protruding movably from the lower surface 20b of the PCa concrete block 20.

[0041] Furthermore, in this embodiment, as shown in Fig. 13 and Fig. 14, a filler injection hole 27 is formed in some of the PCa concrete blocks 20' (see Fig. 8) of the PCa concrete blocks 20, penetrating the hexahedral shape in the vertical direction. A female screw member 27a to which a male screw portion of an opening / closing valve member 28 is screwed is fixed to the middle portion in the vertical direction of each filler injection hole 27. An upper trumpet-shaped recess 27b is formed from the portion where the female screw member 27a of each filler injection hole 27 is fixed, expanding in diameter upward and opening on the upper surface portion 20a of the PCa concrete block 20', and a lower trumpet-shaped recess 27c is formed from the portion where the female screw member 27a is fixed, expanding in diameter downward and opening on the lower surface portion 20b of the PCa concrete block 20'. In these filler injection holes 27, the male threaded portion of the opening / closing valve member 28 is screwed into the female threaded member 27a, and the handle portion 28a is positioned above the upper surface 20a of the PCa concrete block 20', so that the opening / closing valve member 28 is removably attached to the PCa concrete block 20' in a state where the handle portion 28a can be opened and closed by working on the upper surface 20a of the PCa concrete block 20'.

[0042] In this embodiment, the PCa concrete blocks 20 (20') are preferably provided with a pair of flat axially opposed faces 20c in the front and rear direction and a pair of flat transversely opposed faces 20d in the left and right direction, each of which is hexahedral in shape, and spacer jigs 29a, 29b can be attached to each of the pair of flat axially opposed faces 20c, 20d in the left and right direction (see Figs. 10, 11(b), and (c)). A plurality of lifting jigs 29c used for lifting each PCa concrete block 20 are embedded and fixed in the upper surface 20a, preferably of hexahedral shape (see Figs. 10, 11(a)).

[0043] In this embodiment, the PCa concrete blocks 20 are formed to have a hexahedral shape with a curved upper surface 20a and lower surface 20b, preferably with a width x of about 1385 to 1435 mm, a vertical width y of about 730 mm, and a height z of about 500 mm, by pouring and hardening concrete into the box-shaped formwork assembled in a shape according to the above-mentioned predetermined hexahedral shape at a manufacturing factory, for example, and then demolded after a predetermined curing period. The PCa concrete blocks 20 are formed to have a width x of about 1385 to 1435 mm, a vertical width y of about 730 mm, and a height z of about 500 mm, and have a weight of about 1300 kg. For example, a preparation reinforcement is arranged inside the box-shaped formwork, and the above-mentioned bolt box 23, female thread anchor 24, and box punching members for the bolt insertion screw hole 25 and filler injection hole 27 are attached to the preparation reinforcement. These can be embedded and fixed in the PCa concrete block 20 or temporarily fixed. In this embodiment, the size, shape, weight, etc. of the PCa concrete block 20 used as the invert block can be appropriately designed according to the capacity of a lifting machine or the like that can be used in the work yard 71 of one side area 55A without affecting the traffic of vehicles in the other side area 55B. For example, the weight of the PCa concrete block 20 can be preferably set to 1000 to 1500 kg.

[0044] In addition, in this embodiment, the multiple PCa concrete blocks 20 are formed to have the same hexahedral shape, so it is possible to efficiently manufacture them by limiting the type of box-shaped formwork used, and since the blocks are of similar weight, the workability during lifting and transportation is improved, and since they can be handled in the same way when lifting and installing in the work yard 71 of one side area 55A, it is possible to easily perform the work of precisely installing each PCa concrete block 20 in a predetermined position, for example, so that they are arranged in a potato-like shape. It is also possible to reduce the manufacturing cost.

[0045] In this embodiment, the invert structure 10 is constructed in each of the one-side regions 55A, 55B, with the two regions sandwiching the center in the transverse direction of the tunnel as a pair of one-side regions, as described above (see Figs. 2 and 3). In the center of the transverse direction of the tunnel in the invert 33, as described above, a plurality of H-shaped steels 35 supporting retaining plate members 57 for preventing the passageway 60 in the other one-side region 55B from being affected when constructing the invert structure 10 in each one-side region 55A, 55B can be erected at a predetermined interval in the axial direction of the tunnel by driving the H-shaped steels 35 into the ground of the invert 33 with the flange portions 35a aligned in the axial direction of the tunnel. For this reason, at the position where these H-shaped steels 35 are erected, at the center side ends of a pair of PCa concrete blocks (center side blocks) 20B adjacent in the axial direction of the tunnel at the center side in the cross direction of the tunnel, cutout recesses 20e having a rectangular cross section can be formed in the corners on both sides sandwiching the gap 21b between them (see FIG. 8). By using the cutout recesses 20e in the corners on both sides, a flange arrangement recess 10a for arranging one flange of the H-shaped steel 35 can be provided in the end face portion (center side end face portion) 10B on the center side in the cross direction of the tunnel of each invert section structure 10, at the portion where the H-shaped steel 35 is erected.

[0046] In this embodiment, as shown in Figures 8 and 9, the multiple PCa concrete blocks 20 constituting the invert section structure 10 have multiple transverse block rows 20D including a receiving side block 20A arranged adjacent to the receiving portion 31c at the lower end of the side wall covering body 31a, a central side block 20B arranged on the transverse central side of the invert section, and one or more intermediate blocks 20C (in this embodiment, one intermediate block 20C) arranged between them, and these PCa concrete blocks 20A, 20B, 20C are arranged in a row in the transverse direction of the tunnel with gaps 21a, 21b maintained between adjacent receiving portions 31c and between adjacent PCa concrete blocks 20A, 20B, 20C, and are also arranged in a row in the axial direction of the tunnel with gaps 21b maintained between adjacent PCa concrete blocks 20A, 20B, 20C (transverse block rows 20D), and are arranged vertically and horizontally in the invert section 33.

[0047] For example, the receiving base side block 20A is installed adjacent to the receiving base portion 31c and temporarily fixed by the temporary fixing means 36, then the intermediate block 20C is installed adjacent to the temporarily fixed receiving base side block 20A, and at the adjacent location between the installed intermediate block 20C and the receiving base side block 20A, they are temporarily fixed by bolt members (not shown) via a bolt box 23 arranged on the upper surface 20a of at least one of the PCa concrete blocks 20A, 20C that is adjacent to the transverse opposing surface 20d.The height and position of each PCa concrete block 20A, 20C are then adjusted, and the bolt members are then fully tightened. Next, the central block 20B is installed adjacent to the intermediate block 20C, and at the adjacent location between the installed central block 20B and the intermediate block 20C, they are temporarily fixed with bolt members via a bolt box 23 arranged on the upper surface 20a of at least one of the PCa concrete blocks 20C, 20B that is adjacent to the transverse opposing surface 20d.After that, the height and position of the central block 20B is adjusted, and the bolt members are finally tightened, thereby installing the multiple PCa concrete blocks 20A, 20B, 20C of each transverse block row 20D that are connected in the transverse direction of the tunnel in the invert portion 33.

[0048] Here, in this embodiment, the temporary fixing means 36 for temporarily fixing the receiving pedestal side block 20A adjacent to the receiving pedestal 31c can be preferably a wire, chain or other such rope 36b whose both ends are locked to a locking member attached to a hole-in anchor 36a buried in the receiving pedestal 31c and a locking member attached to a bolt box 23 or a hanging jig 29c provided on the receiving pedestal side block 20A. The wire, chain or other such rope 36b can be provided with an expansion and contraction adjustment means 36c, for example a turnbuckle, capable of adjusting the length between the both locked ends. This makes it possible to adjust the width of the gap 21a maintained between the receiving pedestal 31c and the adjacent receiving pedestal side block 20A.

[0049] In this embodiment, the height of each of the PCa concrete blocks 20A, 20B, and 20C can be adjusted by using three height adjustment bolts 26 screwed into the bolt insertion screw holes 25 formed in the above-mentioned three locations, as shown in Fig. 12. That is, each of the PCa concrete blocks 20A, 20B, and 20C has three bolt insertion screw holes 25 formed in the vertical direction, and the height adjustment bolts 26 are attached to each of the bolt insertion screw holes 25 in a state in which the lower end portions 26a can be protruded downward from the lower surface portions 20b of the PCa concrete blocks 20A, 20B, and 20C. Prior to the process of filling the gaps 21a between adjacent receiving portions 31c of a plurality of PCa concrete blocks 20A, 20B, 20C arranged vertically and horizontally with the filling solidification material 22, the gaps 21b between adjacent PCa concrete blocks 20A, 20B, 20C, and the gaps 21c below the hexahedral lower surface portions 20b communicating with these gaps 21a, 21b (see FIG. 13), a process of adjusting the height and inclination of each of the PCa concrete blocks 20A, 20B, 20C is performed by rotating the PCa concrete blocks 20A, 20B, 20C from above to change the protruding lengths of the three height adjustment bolts 26 in each of the PCa concrete blocks 20A, 20B, 20C from the lower surface portions 20b of the PCa concrete blocks 20A, 20B, 20C.

[0050] As described above, in this embodiment, a nut member is preferably fixed as a female screw member 25a to the lower part of each bolt insertion screw hole 25 from the vertical middle part, and the height adjustment bolt 26 is screwed to this nut member 25a, so that the height adjustment bolt 26 is attached in a state in which the lower end 26a can be protruded downward from the lower surface part 20b of the PCa concrete block 20A, 20B, 20C. In addition, a tiltable ground adjuster 26b can be attached to the lower end 26a of the height adjustment bolt 26. This allows the lower end 26a of the height adjustment bolt 26 to be grounded in a stable state on, for example, the ground surface that becomes the filling bottom surface part 26c below the lower surface part 20b. The grounding adjuster 26b can also be shaped so that when the height adjustment bolt 26 is retracted upward, the opening peripheral portion of the bolt insertion hole 25 can be tapered so that it can be accommodated in the above-mentioned small trumpet-shaped recess 25c, which expands downward and is formed in the underside 20b of the PCa concrete blocks 20A, 20B, 20C.

[0051] In this embodiment, the upper end 26d of the height adjustment bolt 26 is preferably formed to have a square cross section, and by engaging an insert extension bar as a rotation operation tool with the upper end 26d and rotating the height adjustment bolt 26, the protruding length of the lower end 26a of the height adjustment bolt 26 from the lower surface 20b of the PCa concrete block 20A, 20B, 20C can be easily changed by working above the upper surface 20a of the PCa concrete block 20A, 20B, 20C. As described above, the bolt insertion screw hole 25 has a large trumpet-shaped recess 25b that expands upward from the portion where the nut member 25a, which is a female screw member, is fixed and opens to the upper surface 20a of the PCa concrete block 20A, 20B, 20C. If the upper end 26d of the height adjustment bolt 26 after the lower end 26a is adjusted to be in contact with the filling bottom surface 26c protrudes from or is close to the upper surface 20a of the PCa concrete block 20A, 20B, 20C, and a sufficient covering thickness cannot be secured above the upper end 26d when the large trumpet-shaped recess 25b is filled with a finishing filler, the upper end 26d of the height adjustment bolt 26 can be appropriately cut to a required length in the large trumpet-shaped recess 25b. This makes it possible to secure a desired covering thickness by the finishing filler such as mortar filled in the bolt insertion screw hole 25, and to prevent the height adjustment bolt 26 from corroding. The work of cutting the upper end 26d of the height adjustment bolt 26 can be performed smoothly because a sufficient working space can be secured in the large trumpet-shaped recess 25b whose diameter expands upward.

[0052] Furthermore, in this embodiment, in the invert structure 10 using the above-mentioned PCa concrete blocks 20A, 20B, 20C, a connecting structure 37 of the PCa blocks in the invert structure can be adopted as the connecting structure for connecting and arranging the multiple PCa concrete blocks 20A, 20B, 20C vertically and horizontally while maintaining gaps 21b of a predetermined spacing width between adjacent PCa concrete blocks 20A, 20B, 20C and installing them as a single unit in the invert structure 33.

[0053] That is, in this embodiment, as shown in Figures 8, 9, and 11(a) to (c), the PCa block connection structure 37 is configured such that, between each pair of transverse opposing surfaces 20d of the PCa concrete blocks 20A, 20B, and 20C adjacent to each other in the transverse direction of the tunnel, transverse spacer jigs 29a (see Figure 11(b)) fixed to one of the opposing surfaces are interposed, preferably in at least three locations, and each pair of PCa concrete blocks 20A, 20B, and 20C adjacent to each other in the transverse direction of the tunnel are connected to each other in a state in which a gap 21b of a predetermined interval width is maintained between the transverse opposing surfaces 20d by the fastening force of bolt members (not shown) fastened by bolt boxes 23 arranged on the upper surface 20a of at least one of the PCa concrete blocks 20A, 20B, and 20C adjacent to the transverse opposing surfaces 20d. In addition, between each pair of axially opposing surfaces 20c of the PCa concrete blocks 20A, 20B, 20C adjacent in the axial direction of the tunnel, axial spacer jigs 29b (see FIG. 11(c)) fixed to one of the axially opposing surfaces 20c are arranged at preferably at least three locations, and each pair of PCa concrete blocks 20A, 20B, 20C adjacent in the axial direction of the tunnel is connected in a state in which a gap 21b of a predetermined interval width is maintained between the axially opposing surfaces 20c by the fastening force of a bolt member (not shown) fastened by a bolt box 23 arranged on the upper surface 20a of at least one of the PCa concrete blocks 20A, 20B, 20C adjacent to the axially opposing surfaces 20c. The transverse spacer jigs 29a and the axial spacer jigs 29b can also be attached to the transversely opposing surfaces 20d and the axially opposing surfaces 20c at the position where the bolt box 23 is provided.

[0054] In this embodiment, the transverse spacer jig 29a and / or the axial spacer jig 29b may be made of mortar blocks, preferably attached and fixed to one of the opposing surfaces 20c, 20d. The mortar block spacer jigs 29a, 29b may be removably attached to the opposing surfaces 20c, 20d, and may be removed after the PCa concrete blocks 20A, 20B, 20C are fully tightened and connected. The transverse spacer jig 29a and / or the axial spacer jig 29b may be made of male thread members, preferably screwed into female thread inserts embedded in one of the opposing surfaces 10c, 10d, so that the protruding length can be adjusted.

[0055] In this embodiment, the multiple PCa concrete blocks 20A, 20B, and 20C arranged in a row and column are integrated through the filling solidification material 22 filled and solidified in the gaps 21a between the adjacent receiving bases 31c, the gaps 21b between the adjacent PCa concrete blocks 20A, 20B, and 20C, and the gaps 21c below the hexagonal lower surface portion communicating with these gaps, as shown in Fig. 13, to form at least a part of the invert section covering body 32. In this embodiment, the filling solidification material 22 can be filled in the gaps 21a between the adjacent receiving bases 31c, the gaps 21b between the adjacent PCa concrete blocks 20A, 20B, and 20C, and the gaps 21c below the hexagonal lower surface portion communicating with these gaps, preferably by a construction method similar to that described in Patent Application No. 2023-58334 and Patent Application No. 2023-58440.

[0056] In this embodiment, the temporary equipment 70 for installing the invert blocks is used when constructing the invert structure 10 as described above in each of the transverse side regions 55A, 55B of the tunnel, as shown in Figures 1(a), (b) and 4, for example, when installing multiple invert blocks made of PCa concrete blocks 20 constituting the invert covering body 32 in one side region 55A by laying them vertically and horizontally on the invert section 33 while ensuring passage on the passageway 60 in the other side region 55B, and is an equipment that allows multiple hexahedral-shaped PCa concrete blocks to be efficiently installed in a row vertically and horizontally without affecting the passage of vehicles in the other side region 55B.

[0057] That is, as shown in Figures 5 and 6, in the work yard 71 of the one-side area 55A, a block lifting lifting machine 74 is movably installed in a space 73 on the rear side of the laying start end 72b of the laying area 72 in the laying direction X, and a digging and lifting heavy machine 76 is movably installed in a space 75 on the front laying end 72c side in the laying direction X from the laying start end 72b in the laying area 72. In addition, a block transport conveyor device 77 is provided as a guide rail on the upper surface of the PCa concrete blocks 20 sequentially installed from the laying start end 72b to the front laying end 72c in the laying area 72, and extends from the laying start end 72b to an area within the working radius of the digging and lifting heavy machine 76. This block transport conveyor device 77 is designed to be able to add to the PCa concrete blocks 20 in the laying direction X as needed as the PCa concrete blocks 20 are sequentially placed in the laying direction X from the laying start end 72b to the laying end end 72c.

[0058] Here, the lifting machine 74 for lifting the block is preferably a crawler crane, and the heavy machine 76 for excavation and lifting is preferably a backhoe. A roller conveyor can be preferably used as the block transport conveyor device (guide rail) 77. In the space 73 behind the starting end 72b of laying in the laying direction X of the laying area 72, the PCa concrete block 20 lifted by the lifting machine 74 for lifting the block can be placed on the roller conveyor 77, preferably with the curved lower surface 20b as the placement surface and with a pair of flat axially opposing surfaces 20c aligned along the extension direction of the roller conveyor 77. As a result, each PCa concrete block 20 moves while rotating the multiple rollers of the roller conveyor 77, and is transported smoothly and stably to a portion adjacent to the heavy machine 76 for excavation and lifting in the space 75 on the side of the end 72c of laying in the laying direction X.

[0059] In addition, the truck, which is the vehicle 80 (see FIG. 1) for transporting the PCa concrete blocks 20, can move from the rear to the work yard 71, preferably on the lane of one side area 55A, without being pulled in sideways from the other side area 55B to the work yard 71 so as not to affect the traffic in the other side area 55B. The PCa concrete blocks 20 loaded on the moving truck 80 can be unloaded into the work yard 71 by a block lifting lifting machine 74. The unloaded PCa concrete blocks 20 can be lifted up appropriately by the block lifting lifting machine 74, for example, and sequentially lowered and placed on the end of the roller conveyor 77 installed on the upper surface of the laid PCa concrete blocks 20 on the side of the laying start end 72b in the laying direction X. The PCa concrete block 20 placed on the starting end 72b of the roller conveyor 77 can be pushed out, for example by a worker, and moved smoothly along the roller conveyor 77 to an area within the working radius of the excavation and lifting heavy equipment 76 installed in the space 75 on the terminal end 72c side of the laying direction X, in front of the block lifting lifting machine 74 on the starting end 72b side.

[0060] In the space 75 on the side of the laying end 72c of the laying area 72 in the work yard 71 where the excavation and lifting heavy equipment 76 is installed, the excavation and lifting heavy equipment 76, which is arranged with the block lifting lifting machine 74 and the driver's cab facing each other, can lift up the PCa concrete blocks 20 that have been transported to the adjacent area along the roller conveyor 77, and sequentially install the lifted PCa concrete blocks 20 at designated positions in the laying area 72 without rotating 180 degrees, preferably with a rotation angle of less than 60 degrees to the left or right, while keeping the driver's cab facing each other so as not to affect the passage of vehicles in the other side area.

[0061] 1(a) and 1(b), in the work yard 71 of the one side area 55A, in the space 73 on the rear side of the laying start end 92b of the laying area 72 in the laying direction X, an auxiliary block lifting lifting machine 78, preferably a crawler crane, is movably installed further rearward of the block lifting lifting machine 74, and an auxiliary block transport conveyor device 79, preferably a roller conveyor, is disposed extending from the area within the working radius of the auxiliary block lifting lifting machine 78 to the area within the working radius of the block lifting lifting machine 74. In the work yard 71 of the one side area 55A, the block lifting lifting machine 74 and the auxiliary block lifting lifting machine 78 are preferably disposed so as to rotate only within the angle range in which the driver's seat is turned away. This makes it possible, preferably by using an auxiliary block lifting lifting machine 78, to unload the PCa concrete blocks 20 loaded onto a truck without increasing the turning width, or to lift them up as appropriate and place them on the end of the auxiliary block transporting conveyor device 79 on the side of the laying starting end 72b.

[0062] Furthermore, in this embodiment, in the work yard 71 of one side region 55A, a transport vehicle 80 loaded with PCa concrete blocks 20, for example a truck, moves in the laying direction X with its loading platform facing forward in the laying direction X, preferably in a space rearward in the laying direction X from the auxiliary block hoisting lifting machine 78. Using the auxiliary block hoisting lifting machine 78, the PCa concrete blocks 20 loaded on the truck 80 can be unloaded without increasing the turning width, or lifted appropriately and placed on the end of the auxiliary block transport conveyor device 79 on the laying start end 72b side.

[0063] In this embodiment, the temporary equipment 70 for installing the invert blocks can also be used in a work yard set up in the other side area 55B that has become the new one-side area, when the other side area 55B of a multiple-lane road tunnel made up of a mountain tunnel 30 is designated as the new one-side area, and the one-side area 55A where construction of the invert structure 10 has been completed is designated as the other side area, while ensuring vehicle passage in the one-side area 55A where construction has been completed, and the invert structure 10 is constructed in the other side area 55B that has become the new one-side area. In other words, when the area above the invert structure 10 formed in one side area 55A is backfilled to restore the passageway and ensure vehicle passage, and then the invert structure 10 is constructed in the other side area 55B as a new side area, a temporary equipment 70 can be used for installing the invert blocks as equipment to enable the efficient installation of multiple PCa concrete blocks 20 laid vertically and horizontally without affecting vehicle passage in the other side area.

[0064] In this embodiment, the inverter structures 10 formed in one side region 55A and the other side region 55B are configured to form an inverter structure 50 extending across the entire transverse area, which together constitute the inverter covering body 32, as shown in Figures 2 and 3.

[0065] That is, the invert section structure 50 covering the entire transverse area is a structure using PCa concrete blocks 20A, 20B, 20C that are provided throughout the entire transverse area of ​​the tunnel in the invert section 33 of the mountain tunnel and constitute the invert section lining body 32, and each of the PCa concrete blocks 20A, 20B, 20C 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 section lining body 32, as described above. As shown in Figures 2 and 3, in each of one side region 55A and the other side region 55B 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 and installed in the invert section 33 with gaps 21a, 21b between the receiving base 31c at the lower end of the adjacent side wall lining body 31a and between the adjacent PCa concrete blocks, and are also arranged in series in the axial direction of the tunnel with gaps 21b between the adjacent PCa concrete blocks 20A, 20B, 20C, thereby forming a one-side block group 20X and an other-side block group 20Y. In addition, a space portion 51 is maintained between the one-side block group 20X and the other-side block group 20Y in the central portion of the transverse direction of the tunnel. The multiple PCa concrete blocks 20A, 20B, 20C arranged vertically and horizontally in the one side block group 20X and the other side block group 20Y are integrated together via the filled solidification material 22 that has been filled and solidified in the gaps 21a between each adjacent receiving portion 31c, the gaps 21b between adjacent PCa concrete blocks 20A, 20B, 20C, 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 that communicates with these gaps 21a, 21b and the spacing portion 51, to form the invert portion covering body 32.

[0066] In addition, in this embodiment, the gaps 21a between adjacent receiving base portions 31c filled with filling solidification material 22, and the gaps 21b between adjacent PCa concrete blocks 20A, 20B, 20C, preferably have a spacing width of 15 to 30 mm, and the spacing portion 51 between one side block group 20X and the other side block group 20Y preferably has a spacing width of 100 to 130 mm.

[0067] Furthermore, in this embodiment, the multiple PCa concrete blocks 20A, 20B, 20C arranged vertically and horizontally in the one side block group 20X and the other side block group 20Y, respectively, are installed in the invert section 33, with the gaps 21b extending in the axial direction between adjacent PCa concrete blocks in the transverse direction of the tunnel, filled with filling solidification material 22, and the gaps extending in the transverse direction between adjacent PCa concrete blocks in the axial direction of the tunnel being preferably all arranged in a potato shape that is continuous in a straight line.

[0068] The invert structure 10 having the above-mentioned configuration is constructed by the construction method of the invert structure of this embodiment, which includes a digging and laying process of excavating the ground 61 (see Figure 4) of the invert section 33 in the area between the lower end portions on both sides of the main body covering body 31, which is provided in advance from the side wall portion 31a of the tunnel 30 to the upper arch-shaped portion 31b, as shown in Figures 7(a) to (e), and laying a plurality of PCa concrete blocks 20 in a row and aligned vertically and horizontally on the leveled base portion 61a.

[0069] That is, in the construction method of the invert section structure of this embodiment, in the excavation and laying process, an excavation process (see Figures 7(a) to (c)) in which the ground 61 of the invert section 33 is excavated by an excavation and lifting heavy equipment 76, and a laying process (see Figures 7(c) and (d)) in which the newly installed PCa concrete blocks 20 are lifted by the excavation and lifting heavy equipment 76 and hung in a predetermined position and laid out are repeatedly performed for a predetermined excavation width W (see Figure 7(c)) in the axial direction of the tunnel in which one or more block rows 20D can be installed, preferably for each width in the axial direction X of the tunnel in which one or two block rows (transverse block rows) 20D can be installed.

[0070] In addition, in this embodiment, for each of one or two rows of blocks 20D laid in the laying process of the excavation and laying process, a process is carried out to integrate the PCa concrete blocks 20 in one or two rows of block rows 20D by filling and solidifying filling solidification material 22 into the gaps 21a between adjacent receiving base portions 31c, the gaps 21b between adjacent PCa concrete blocks 20, and the gaps 21c below the hexahedral lower surface portion 20b that communicates with these gaps 21a, 21b (see Figure 7(e)).

[0071] In the excavation step of the excavation and laying step, as shown in Figures 7(a) to (c), a heavy excavation and lifting machine 76, preferably a backhoe, is arranged facing the rear side of the laying direction X on the ground 61 of the invert part 33 on the front side of the laying direction X in the axial direction of the tunnel 30, and while moving (retreating) the backhoe 76 to the front side in the laying direction X, the ground 61 of the invert part 33 is excavated by the bucket of the backhoe 76 with a predetermined excavation width W (see Figure 7(c)) that allows installation of preferably one or two block rows 20D made of PCa concrete blocks 20. The bottom plate part 61a of the ground 61 of the excavated invert part 33 can be appropriately leveled, for example, by manual labor.

[0072] In addition, in the laying process of the excavation and laying process, as shown in Figures 7(c) and (d), the newly installed PCa concrete blocks 20, which have been transported from the rear side to the front side in the laying direction X in the axial direction of the tunnel via a roller conveyor 77 and supplied from the rear space 73 by a block lifting lifting machine 74, preferably a crawler crane, are lifted by the backhoe 76 placed on the ground 61 of the forward invert section 33, for example, using a lifting wire (not shown) engaged with a lifting hook provided on the bucket of the backhoe 76, and then hoisted into a predetermined position on the base plate section 61b that has been leveled to a predetermined excavation width W after being excavated in the excavation process, so that they can be laid out and installed.

[0073] The multiple PCa concrete blocks 20 that make up the installed block rows 20D, preferably one or two rows, are each stably positioned at a predetermined position via the above-mentioned temporary fixing means 36 and PCa block connecting structure 37 (see Figure 9), and if necessary, a process can be carried out to integrate the PCa concrete blocks 20 in one or two block rows 20D (see Figure 7(e)) by filling and solidifying filling solidification material 22 into the gaps 21a between adjacent receiving base portions 31c, the gaps 21b between adjacent PCa concrete blocks 20, and the gaps 21c below the hexahedral lower surface portion that communicates with these gaps, preferably for each block row 20D (see Figure 13). In addition, for example, the gap between the integrated one or two block rows 20D and the end face portion of the ground 61 (see Figure 4) of the invert portion 33 of the other side region 55Y can also be filled with and solidified using filling solidification material 22, or filled with crushed stone or the like and compacted, thereby making it possible to form an annular support structure in which the integrated one or two block rows 20D, the main body covering body 31, and the ground 61 of the invert portion 33 of the other side region 55Y are connected in a ring shape as a single unit in the circumferential direction in each of the one or two block rows 20D.

[0074] As a result, according to this embodiment, even if the annular support structure, which is continuous in a circular shape in cross section and is formed integrally with the main body covering body 31 and the ground 61 of the invert section 33 by excavating the ground 61 of the invert section 33 in the area between the lower end portions on both sides of the main body covering body 31 installed earlier, becomes discontinuous in the excavated part of the ground 61 of the invert section 33, it is possible to eliminate this state of discontinuity in the excavated part of the invert section 33 and to enable the annular support structure including the main body covering body 31 to be closed early in the part of each of the one or two rows of block rows 20D, thereby effectively avoiding any impact on the ground around the main body covering body 31.

[0075] After the PCa concrete blocks 20 of preferably one or two block rows 20D are integrated via the filling solidification material 22, the roller conveyor 77 is extended up to the top of the newly integrated one or two block rows 20D (see FIG. 7(e)). In addition, the backhoe 76 is then moved (retreated) forward in the laying direction X by the excavation width W of the one or two block rows 20D, and the excavation and laying steps of the excavation and laying step are repeated in the same manner as described above, and a step of integrating a plurality of PCa concrete blocks 20, preferably for each one or two block rows 20D, via the filling solidification material 22 is carried out as necessary, so that the plurality (many) PCa concrete blocks 20 constituting the invert section covering body 32 and the invert section structure 10 can be efficiently laid over the entire laying area 72.

[0076] Furthermore, the work of integrating multiple PCa concrete blocks 20 that have been laid out side by side using the filling solidification material 22 does not necessarily have to be carried out for each one or two block rows 20D. For example, multiple PCa concrete blocks 20 can be integrated by filling the filling solidification material 22 after installing multiple PCa concrete blocks 20 over the entire laying area 72, or for each specified construction span in the laying area 72.

[0077] Furthermore, according to the construction method of the invert structure of this embodiment having the above-mentioned configuration, in the inner area of ​​the main body covering body 31 extending from the side wall portions 31a on both sides of the tunnel 30 to the upper arch-shaped portion 31b, it is possible to efficiently excavate the ground 61 of the invert portion 33 using as few heavy machinery as possible, and to lay a large number of PCa concrete blocks 20 in a row vertically and horizontally in predetermined positions.

[0078] That is, in the construction method of the invert section structure of this embodiment, the construction is performed including an excavation and laying process in which the ground 61 of the invert section 33 is excavated and a plurality of PCa concrete blocks 20 are laid in a line. In the excavation and laying process, the ground 61 of the invert section 33 is excavated with a predetermined excavation width W in the axial direction of the tunnel in which one or more rows of blocks 20D can be installed, while preferably the backhoe 76 arranged on the ground 61 of the invert section 33 on the front side of the laying direction X is moved forward (retreated). In the laying process, the newly installed PCa concrete block 20 that has been transported to the front side in the laying direction X by passing over the PCa concrete block 20 previously installed is lifted by the backhoe 76 facing in the same direction as the direction in the excavation process, and is hung on the base plate portion 61b that has been leveled with the predetermined excavation width W after excavation, so that each is laid in a line and installed.

[0079] As a result, according to this embodiment, the excavation and lifting heavy machine, preferably the back-forged machine 76, can move forward (backward) without making a large turn while facing the rear side in the laying direction X, and can carry out the excavation process, the subsequent laying process, and the next excavation process. In addition, the newly installed PCa concrete block 20 is transported from the rear side opposite the back-forged machine 76, sandwiched between the block row 20D of the previously installed PCa concrete blocks 20, to the front side in the laying direction X, and is lifted up by the back-forged machine 76. Therefore, even when working in a narrow space such as the inner area of ​​the main body lining 31 extending from the side wall portions 31a on both sides of the tunnel 30 to the upper arch-shaped portion 31b, it is possible to efficiently lay these PCa concrete blocks 20 using as few heavy machines as possible while avoiding entanglement between the heavy machines.

[0080] The present invention is not limited to the above embodiment and can be modified in various ways. For example, in the laying step of the excavation and laying process, the newly installed PCa concrete blocks may be placed on a preferably electric transport vehicle that can run on the rows of blocks that have been laid and installed in advance, and transported from the rear to the front in the laying direction. The predetermined excavation width by which the ground of the invert part is excavated by the excavation and lifting heavy machine may be the axial width of the tunnel in which three or more rows of blocks can be installed.

[0081] The construction method of the invert structure of the present invention is not limited to the case where the invert structure is formed on each side of the center line of the tunnel in the transverse direction, but can also be adopted when, for example, the invert structure is formed at once on both sides of the center line of the tunnel in the transverse direction while completely blocking traffic through the tunnel. Even in this case, for each of the one or two rows of blocks laid in the laying process of the preferred excavation laying process, a filling solidification material is filled and solidified in, for example, the gaps between the adjacent support parts on both sides, the gaps between the adjacent PCa concrete blocks, and the gaps below the lower surface part of the hexahedron shape that communicates with these gaps, to integrate the PCa concrete blocks of the one or two rows of blocks. This makes it possible to effectively avoid the influence of the annular support structure that is closed early on by forming an annular support structure that is continuous in a ring shape as an integral part of the integrated one or two rows of block rows 20D and the main body lining body in the circumferential direction.

[0082] In addition, the construction method of the invert structure of the present invention can be used not only when forming a new invert lining in an existing mountain tunnel where no invert lining has been formed, but also when forming an invert structure by excavating the ground of the invert in the area between the lower ends on both sides of the main body lining that has been formed in advance in the area from the side wall to the upper arch-shaped portion in construction of a new mountain tunnel. [Explanation of symbols]

[0083] 10 Inverter structure 20,20' PCa concrete block 20D Block Row 21a Gap between the support and the base 21b Gaps between adjacent PCa concrete blocks 21c Lower gap of the bottom surface 21d Gap between existing invert structure 22 Filling and solidification materials 23 Bolt Box 24 Female thread anchor 25 Bolt insertion hole 26 Height adjustment bolt 27 Filler injection hole 28 Opening and closing valve parts 30 Mountain Tunnel 30a Bottom panel part 31 Main body lining 31a Side wall part 31b Arch-shaped part 31c pedestal part 32 Invert section lining 33 Inverter 35 H type steel 36 Temporary fixing means 37 PCa block joint structure 42 Air bleed hose 50 Invert structure of the entire cross section of the tunnel 51 Interval between one side block group and the other side block group 55A One side area 55B Other side area 60 Passage route 61 Inverted Ground 61a Bottom panel 70 Temporary equipment for installing invert blocks 71 Working Yard 72 Laying area 72b Beginning of laying 72c Laid-out termination 73 Space behind the start of laying in the laying area 74 Block lifting machine (crawler crane) 75 Space on the side of the end of the laying in the laying area 76 Excavation and lifting heavy equipment (backhoe) 77 Block transport conveyor device (guide rail) 78 Lifting machine for auxiliary blocks 79 Auxiliary block transport conveyor device 80 Transport vehicles (trucks) W the desired excavation width X Laying direction (tunnel axis direction) Y Tunnel Transverse Direction

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, The invert section structure is arranged in such a manner that the multiple PCa concrete blocks are arranged in a row in the transverse direction of the tunnel and installed in the invert section, with gaps maintained between the receiving base portions of the lower ends of adjacent main body covering bodies and between adjacent PCa concrete blocks, and are also arranged in a row vertically and horizontally and installed in the invert section, with gaps maintained between adjacent PCa concrete blocks in the axial direction of the tunnel, and the multiple PCa concrete blocks arranged in a row vertically and horizontally are integrated via a filling solidification material that is filled and solidified in the gaps between adjacent receiving base portions, the gaps between adjacent PCa concrete blocks, and the gaps below the hexahedral lower surface portion that communicate with these gaps, thereby forming the invert section covering body. The invert structure is constructed by excavating the ground of the invert in the region between the lower ends of both sides of the main body covering body provided in advance of the arch-shaped portion at the upper part from the side wall of the tunnel, and laying a plurality of the PCa concrete blocks in a row vertically and horizontally on the leveled base plate. In the excavation and laying process, a heavy machine for excavating and lifting is placed on the ground of the invert part on the front side of the laying direction in the axial direction of the tunnel, facing the rear side in the laying direction, and the heavy machine for excavating and lifting is moved forward in the laying direction to excavate the ground of the invert part with the heavy machine for excavating and lifting, and one or more rows of blocks formed by connecting the PCa concrete blocks in the transverse direction of the tunnel can be installed in a predetermined excavation width in the axial direction of the tunnel; and a method of laying and installing the newly installed PCa concrete block that has been transported from the rear side in the laying direction in the axial direction of the tunnel to the front side by passing over the PCa concrete blocks that have been laid and installed previously, is carried out by the heavy machine for excavating and lifting placed on the ground of the invert part on the front side, and is lifted by the heavy machine for excavating and lifting placed on a predetermined position of the base plate that has been leveled with the predetermined excavation width after being excavated in the excavation process, thereby laying and installing each of the newly installed PCa concrete blocks.

2. A construction method for an invert structure as described in claim 1, wherein the specified excavation width for excavating the ground of the invert section using the excavation and lifting heavy equipment is the axial width of a tunnel in which one or two rows of blocks can be installed.

3. A construction method for an invert structure as described in claim 2, wherein a base plate portion is excavated to the specified excavation width in the axial direction of the tunnel, so that one or two rows of blocks can be installed, and a plurality of the PCa concrete blocks are laid out in a single or two rows in a continuous arrangement on the leveled base plate portion, and the gaps between adjacent support portions, the gaps between adjacent PCa concrete blocks, and the gaps below the hexahedral lower surface portion communicating with these gaps are filled with a filling solidification material for each of the one or two rows of blocks laid out, and solidified, thereby integrating the PCa concrete blocks of the one or two rows of block rows.

4. 3. A method for constructing an invert structure according to claim 1 or 2, wherein the excavation and lifting heavy machinery is a backhoe.

5. 3. A construction method for an invert structure as described in claim 1 or 2, wherein, in the laying process of the excavation and laying process, the newly installed PCa concrete block is placed on a guide rail laid on top of the row of blocks that have been laid and installed previously, and is transported from the rear to the front in the laying direction.

6. 3. A construction method for an invert structure as described in claim 1 or 2, wherein, in the laying process of the excavation and laying process, the newly installed PCa concrete block is placed on a transport cart that can run over the row of blocks that have been laid and installed previously, and is transported from rear to front in the laying direction.

7. 3. A construction method for an invert section structure as described in claim 1 or 2, wherein, in the laying process of the excavation and laying process, the newly installed PCa concrete block is supplied onto the block row from the rear side in the laying direction in the axial direction of the tunnel using a block lifting lifting machine arranged on the ground of the invert section rear of the block row made of the PCa concrete blocks previously laid and installed.

8. 3. A construction method for an invert section structure as described in claim 1 or 2, wherein the multiple PCa concrete blocks arranged in a row vertically and horizontally are arranged in a potato-like shape in which the gaps between the PCa concrete blocks adjacent in the transverse direction of the tunnel and the gaps between the PCa concrete blocks adjacent in the axial direction of the tunnel are both continuous in a straight line, and the PCa concrete blocks are installed in the invert section.

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