Block connection structure in the invert structure

Abstract

To provide a block connection part structure enabling an invert part structure to be easily formed so as to correspond to a tunnel alignment curving in a vertical direction using PCa concrete blocks.SOLUTION: Spacer jigs 29b at least at three locations are interposed between axial direction facing surfaces 20c facing in an axial direction of a tunnel at a connection part 20g in an axial direction of the tunnel between transverse direction block rows 20D consisting of PCa concrete blocks connected in the axial direction of the tunnel. The spacer jig is fastened to the axial direction facing surfaces 20c in a state where an interposed width is adjusted so that a spacing width of the upper gap 21b held by the axial direction spacer jig 29b disposed on an upper stage is different from a spacing width of the lower gap 21b held by the axial direction spacer jig 29b disposed on a lower stage.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a block connection structure in an invert structure, and in particular to a block connection structure in an invert structure using PCa concrete blocks, which are installed in the invert of a mountain tunnel and form an invert lining. [Background technology]

[0002] A mountain tunnel is a tunnel formed by excavating a self-supporting and relatively stable foundation 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 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 lining body of a predetermined thickness made of concrete 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 a predetermined thickness using concrete in the transverse direction of the tunnel in the part between the receiving parts at the lower ends of the pair of side walls. Thus, 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 in a shorter period of time.

[0005] For these reasons, consideration has been given to shortening the construction period by forming the invert section covering body using precast concrete components manufactured in advance in a factory or the like (see, for example, Patent Document 2 and Patent Document 3). [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 Summary of the Invention [Problem to be solved by the invention]

[0007] However, according to the conventional construction method of the invert section in a mountain tunnel using concrete members made of precast concrete, these concrete members formed in advance in a factory or the like are formed to a length covering the entire width of the invert section in the transverse direction, or to a length dividing the invert section in two or three parts in the transverse direction, so that they are heavy and have a large shape, and it takes a lot of effort to assemble the formwork in a factory or the like and to form the joint section with high accuracy. Furthermore, it requires a lot of effort to transport and assemble at the construction site, and especially in a multi-lane road tunnel, for example, when construction is carried out for each lane while maintaining traffic in the other lane, it is difficult work because bulky concrete members are used. In addition, since a road tunnel may include a portion where the tunnel line is curved in the vertical direction, it is desirable to be able to accommodate such a curved line.

[0008] The present invention aims to provide a block connection structure in an invert structure, which is a constituent part of an invert lining body that is installed continuously from the side wall of a tunnel to the lining body of the upper arch-shaped part, without requiring much effort, by using precast concrete blocks (PCa concrete blocks) of appropriate weight and size that can be easily manufactured in a factory, etc., to easily form the invert structure in accordance with the tunnel linear shape that curves vertically. [Means for solving the problem]

[0009] The present invention relates to an invert structure using PCa concrete blocks that constitutes an invert lining formed in an invert section of a mountain tunnel, and relates to a block connection structure in the invert structure for connecting a plurality of PCa concrete blocks vertically and horizontally along a tunnel linear line curved in the vertical direction to be integrally installed in the invert section, while maintaining a gap of a predetermined interval between the adjacent PCa concrete blocks. Each of the PCa concrete blocks 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 lining body, and between each pair of transverse opposing surfaces of the PCa concrete blocks adjacent in the transverse direction of the tunnel that face each other in the transverse direction, transverse spacer jigs fixed to one of the transverse opposing surfaces are disposed at at least three locations and interposed, and each pair of the PCa concrete blocks adjacent in the transverse direction of the tunnel are connected by the fastening force of the bolt members while maintaining a gap of a predetermined interval between the transverse opposing surfaces. a transverse block row is formed by a plurality of the PCa concrete blocks, and between each pair of axially opposing faces of the PCa concrete blocks adjacent in the axial direction of the tunnel that face each other in the axial direction, axial spacer jigs fixed to one of the axially opposing faces are arranged and interposed at at least three locations, and each pair of the PCa concrete blocks adjacent in the axial direction of the tunnel are connected by the fastening force of bolt members while maintaining a gap of a predetermined interval between the axially opposing faces, and in one or more tunnel axial connection portions between the transverse block rows that are consecutively arranged in the axial direction of the tunnel, the at least three axial spacer jigs interposed between each of the axially opposing faces that face each other in the axial direction of the tunnel are fixed to the axially opposing faces with their interposition widths adjusted so that the interval width of the upper gap held by the axial spacer jig arranged in the upper tier and the interval width of the lower gap held by the axial spacer jig arranged in the lower tier are different widths, thereby providing a block connection structure in an invert structureThe above objective has been achieved.

[0010] Furthermore, it is preferable that the block connection structure in the inverter structure of the present invention has an intervening width adjusted so that the spacing width of the upper gap held by the axial spacer jig arranged in the upper tier is larger than the spacing width of the lower gap held by the axial spacer jig arranged in the lower tier, thereby making it possible to arrange multiple adjacent widthwise block rows along the tunnel linear shape that curves downward in the vertical direction.

[0011] In addition, it is preferable that the block connection structure in the inverter structure of the present invention has an intervening width adjusted so that the spacing width of the upper gap held by the axial spacer jig arranged in the upper tier is smaller than the spacing width of the lower gap held by the axial spacer jig arranged in the lower tier, thereby making it possible to arrange multiple adjacent transverse block rows along the tunnel linear shape that curves upward in the vertical direction.

[0012] Furthermore, the connection structure of the blocks in the inverter structure of the present invention is made of mortar blocks in which the axial spacer jig is attached and fixed to one of the axial opposing surfaces, and it is preferable that by fixing mortar blocks of different sizes to the upper and lower rows, the spacing width can be adjusted so that the spacing width of the gap held at the upper part and the spacing width of the gap held at the lower part are different widths.

[0013] Furthermore, the connection structure of the blocks in the inverter structure of the present invention is formed by a male threaded member fixed so that the protruding length can be adjusted by screwing the axial spacer jig into a female threaded insert embedded in one of the axial opposing surfaces, and it is preferable that the male threaded members are screwed and fixed with different threading amounts in the upper and lower stages, making it possible to adjust the interval width so that the spacing width of the gap held in the upper part and the spacing width of the gap held in the lower part are different widths. Effect of the Invention

[0014] According to the block connection structure in the invert structure of the present invention, by using precast concrete blocks (PCa concrete blocks) of appropriate weight and size that can be easily manufactured in a factory, etc., the invert structure, which is a constituent part of the invert lining and is installed continuously from the side wall of the tunnel to the lining of the upper arch-shaped part, can be easily formed to correspond to the tunnel linear shape that curves vertically, without requiring much effort. [Brief description of the drawings]

[0015] [Figure 1] This is a schematic cross-sectional view illustrating a mountain tunnel in which an invert structure using a block connection structure according to a preferred embodiment of the present invention is formed on both sides of the invert in the transverse direction of the tunnel. [Diagram 2] This is a schematic top view of Figure 1 viewed from the AA direction, illustrating the state in which an invert structure using a block connection structure according to a preferred embodiment of the invention is formed on both sides over the entire area of ​​the invert in the transverse direction of the tunnel. [Diagram 3] This is a schematic top view of an invert section structure according to a preferred embodiment of the present invention, provided in one side region of the invert section in the transverse direction of the tunnel. [Figure 4] 4 is a schematic cross-sectional view taken along line BB in FIG. 3 before the filling solidification material is filled. [Diagram 5] This is an oblique view of the PCa concrete block that constitutes the invert structure. [Figure 6] (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 7]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 8] 1A is a perspective view illustrating a ground adjuster attached to a lower end of a height adjustment bolt, and FIG. 1B is a schematic cross-sectional view illustrating another preferred embodiment of a small trumpet-shaped recess. [Figure 9] FIG. 1(a) is a conceptual diagram illustrating the situation in which PCa concrete blocks are connected and installed in a state aligned with the tunnel line curved in the horizontal direction, and FIG. 1(b) is a conceptual diagram illustrating the situation in which PCa concrete blocks are connected and installed in a state aligned with the tunnel line curved in the vertical direction, using a block connection structure according to a preferred embodiment of the present invention. [Figure 10] 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 11] 2 is a schematic cross-sectional view in the transverse direction of a PCa concrete block along a portion in which a filler injection hole is formed, illustrating a filler injection hole and an opening / closing valve member. FIG. [Figure 12] 1 is a schematic top view of an invert structure illustrating the injection status of filling solidification material. FIG. [Figure 13] This is an explanatory diagram of an upper surface band plate-shaped formwork that closes gaps on the upper surface of a PCa concrete block. [Figure 14] An explanatory diagram of a gable band plate-shaped formwork that closes the gap at the gable end surface. [Figure 15] FIG. 2 is an explanatory diagram of the unevenness formed on the surface of the central portion of a PCa concrete block. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The invert structure 10 using a block connection structure 70 (see Figure 9 (b)) according to a preferred embodiment of the present invention is continuous with the lining 31 in the area from both side wall portions 31a to the upper arch-shaped portion 31b, which was previously formed to cover the inner wall surface of the mountain tunnel 30 shown in Figure 1, and is constructed on each side of the transverse center line C of the tunnel, as shown in Figures 2 and 3, and integrated to form a structure that becomes a constituent part of the invert lining 32 when a new invert lining 32 is formed on the base portion 30a of the mountain tunnel 30.

[0017] 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 in the area 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.

[0018] In addition, when a new invert lining 32 is formed in an existing mountain tunnel 30, it is necessary to block traffic through the tunnel, so it is desirable to complete the construction in as short a period as possible. In this embodiment, the invert structure 10 uses a plurality of precast concrete blocks (PCa concrete blocks) of an appropriate weight and size that are easy to handle and are manufactured in advance in a factory or the like, so that it can be easily formed one side at a time without much effort, and the invert lining 32 that is continuous with the lining 31 in the region from the side wall 31a of the tunnel to the upper arch-shaped portion 31b can be installed in a shorter period of time, and the invert structure 10 can be formed in accordance with the tunnel linear shape S2 that curves in the vertical direction (perpendicular direction) by using the block connection structure 70 of this embodiment.

[0019] The block connection structure 70 (see FIG. 9(b)) in the invert structure of this embodiment is a structure of the connection of the PCa concrete blocks 20 in the invert structure 10 using the PCa concrete blocks 20 constituting the invert lining 32 formed in the invert 33 of the mountain tunnel 30, in which a gap 21b of a predetermined interval is maintained between adjacent PCa concrete blocks 20, and the PCa concrete blocks 20 are connected vertically and horizontally in a state along the tunnel linear shape S2 curved in the vertical direction (vertical direction) to be installed as a single unit in the invert 33. As shown in FIGS. 1 to 6 and 9(a), each PCa concrete block 20 is formed as a hexahedral block having a curved upper surface portion 20a and a curved lower surface portion 20b so as to have a curved shape along the cross-sectional shape of the invert lining 32 (see FIGS. 5 and 6(a) to (c)). Between each pair of transverse opposing surfaces 20d of adjacent PCa concrete blocks 20 facing in the transverse direction of the tunnel, transverse spacer jigs 29a fixed to one of the transverse opposing surfaces 20d are positioned at at least three locations, and each pair of PCa concrete blocks 20 adjacent in the transverse direction of the tunnel are connected by the fastening force of bolt members (not shown) while maintaining a gap 21b of a predetermined spacing width between the transverse opposing surfaces 20d, forming a transverse block row 20D made up of a plurality of PCa concrete blocks 20 (see Figure 3).

[0020] Between each pair of axially opposing surfaces 20c of adjacent PCa concrete blocks 20 facing in the axial direction of the tunnel, axial spacer jigs 29b fixed to one of the axially opposing surfaces 20c are arranged in at least three locations, and each pair of PCa concrete blocks 20 adjacent in the axial direction of the tunnel is connected by the fastening force of bolt members (not shown) while maintaining a gap 21b of a predetermined spacing width between the axially opposing surfaces 20c. Furthermore, in one or more axial connection portions 20g of the tunnel between multiple transverse block rows 20D arranged in the axial direction of the tunnel (see Figure 9 (b)), at least three axial spacer jigs 29b interposed between each axial opposing surface 20c facing in the axial direction of the tunnel are fixed to the axial opposing surfaces 20c with their interposition widths adjusted so that the gap width of the upper gap 21b held by the axial spacer jig 29b arranged in the upper stage and the gap width of the lower gap 21b held by the axial spacer jig 29b arranged in the lower stage are different widths.

[0021] In this embodiment, the invert structure 10 is a structure of the invert section 33 using PCa concrete blocks 20 that is provided in at least one side region of the invert section 33 of a mountain tunnel 30 in the transverse direction of the tunnel, as shown in Figures 1 to 4, and constitutes the invert section lining body 32, and the PCa concrete blocks 20 are formed as hexahedral blocks having curved upper surface portions 20a and lower surface portions 20b so that they each have a curved shape that follows the cross-sectional shape of the invert section lining body 32, as shown in Figures 5 and 6(a) to (c). These PCa concrete blocks 20 are arranged in a row in the transverse direction of the tunnel and installed in the invert section 33 with gaps 21a and 21b between the support 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 a row in the axial direction of the tunnel with gaps 21b between the adjacent PCa concrete blocks and installed in the invert section 33 (see Figs. 1 to 4). As shown in Fig. 10, the PCa concrete blocks 20 arranged in a row in the vertical and horizontal directions constitute one side of the invert lining body 32 as at least a part of the invert lining body 32 in a state of being integrated through the filling solidification material 22 filled and hardened in the gaps 21a between the adjacent support 31c, the gaps 21b between the adjacent PCa concrete blocks 20, and the gaps 21c below the hexahedral lower surface communicating with these gaps 21a and 21b.

[0022] In this embodiment, the multiple 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. 5, FIG. 6(a) to (c)). The multiple 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 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. 2 and FIG. 3). The gaps 21a between the adjacent receiving base parts 31c filled with the filling solidification material 22 and the gaps 21b between the adjacent PCa concrete blocks are preferably gaps with an interval width of about 15 to 30 mm.

[0023] In this embodiment, the PCa concrete blocks 20 constituting the invert structure 10 are arranged in series in the transverse direction of the tunnel with the 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 20, and are arranged in series in the axial direction of the tunnel with the gaps 21b between the adjacent PCa concrete blocks and the filling solidification material 22, and are arranged vertically and horizontally in the invert section 33. As shown in Figs. 5 and 6(a) to (c), the PCa concrete block 20 has a curved upper surface 20a and a lower surface 20b that are curved along the cross-sectional shape of the invert lining body 32, and is formed as a hexahedral block having a pair of flat axially opposing surfaces 20c in the front and rear and a pair of flat transversely opposing surfaces 20d in the left and right. The upper surface portion 20a and the lower surface portion 20b in cross section can be gently curved with a radius of curvature of, for example, about 14000 mm to 14500 mm.

[0024] Furthermore, in each of these PCa concrete blocks 20, a bolt box 23 or a female screw anchor 24 is embedded and fixed to the four sides of the upper surface portion of the hexahedron shape to connect adjacent PCa concrete blocks 20 using a bolt member (not shown). The bolt box 23 opens on the upper surface portion 20a of the PCa concrete block 20, and the female screw anchor 24 opens on the upper end of the axially facing surface 20c or the transversely facing surface 20d of the side portion. As shown in FIG. 7, 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. 6(a)). A female screw member 25a to which a height adjustment bolt 26 is screwed is fixed to each bolt insertion screw hole 25 at a portion lower than the middle portion in the vertical direction. 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 26a protruding movably from the lower surface 20b of the PCa concrete block 20. In addition, since the large trumpet-shaped recess 25b and the small trumpet-shaped recess 25c have a trumpet shape that tapers toward the upper and lower openings, a box punching member attached to a box-shaped formwork for pouring concrete to form the trumpet-shaped recesses 25b and 25c can be smoothly removed after the concrete hardens. From this viewpoint, it is preferable that the taper gradient of the large trumpet-shaped recess 25b and the small trumpet-shaped recess 25c, which have a tapered trumpet shape that tapers toward the upper and lower openings, is 10% or more inclined with respect to the central axis of the bolt insertion screw hole 25.

[0025] As shown in Figure 6(a), the three bolt insertion screw holes 25 are formed on the upper surface 20a of the PCa concrete block 20, preferably at each corner of an imaginary isosceles triangle (see dotted line) with the base positioned parallel to one axial opposing surface 20c and the apex positioned on the other axial opposing surface 20c (see Figure 6(a)).

[0026] In this embodiment, it is preferable that the center of gravity of the PCa concrete block 20 is located inside the imaginary isosceles triangle when viewed from the top side of the PCa concrete block 20, and it is particularly preferable that the center of gravity of the PCa concrete block 20 is located at the position of the centroid of the imaginary isosceles triangle. This makes it possible to adjust the height and inclination of the PCa concrete block 20 with the three height adjustment bolts 26 in a more stable and accurate state, and also makes it possible to support the PCa concrete block 20, whose height and inclination have been accurately adjusted, in a more stable state by the three height adjustment bolts 26.

[0027] Furthermore, as shown in Fig. 10 and Fig. 11, a filler injection hole 27 is formed in some of the PCa concrete blocks 20' (see Fig. 3) that penetrates the hexahedron shape in the vertical direction. A female screw member 27a is fixed to the vertical middle portion of each filler injection hole 27, to which the male screw portion of the opening and closing valve member 28 is screwed. 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 screw part of the opening / closing valve member 28 is screwed into the female screw member 27a, and the handle part 28a is disposed above the upper surface part 20a of the PCa concrete block 20', so that the opening / closing valve member 28 is detachably attached to the PCa concrete block 20' in a state in which the handle part 28a can be opened and closed by working on the upper surface part 20a of the PCa concrete block 20'. In addition, since the upper side trumpet-shaped recess 27b and the lower side trumpet-shaped recess 27c have a trumpet shape that tapers toward the upper and lower openings, it is possible to smoothly remove the box punching member attached to the box-shaped formwork for pouring concrete to form these trumpet-shaped recesses 27b and 27c after the concrete has hardened. From this point of view, it is preferable that the taper gradient of these trumpet-shaped recesses 27b and 27c is also inclined by 10% or more with respect to the central axis of the filler injection hole 27.

[0028] In this embodiment, the filler injection hole 27 penetrating the hexahedral PCa concrete block 20' in the vertical direction can be preferably formed in the center of the upper surface 20a of the PCa concrete block 20' (see FIG. 6(a)). In particular, it is preferable that the filler injection hole 27 is formed in the center of the center-side block 20B that is located at the lowest position.

[0029] 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 can be fitted with spacer jigs 29a, 29b at at least one location for maintaining a predetermined gap width 21b between the other opposed faces 20c, 20d (see Figs. 5, 6(b), and (c)). A plurality of lifting jigs 29c used for lifting each PCa concrete block 20 are embedded and fixed in the upper face 20a of the hexahedron (see Fig. 6(a)).

[0030] 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.

[0031] 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 they can be handled in the same way when lifting and installing, so it is easy to accurately install 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 manufacturing costs.

[0032] In this embodiment, the invert structure 10 is constructed in each of the pair of one-side regions, with the regions on both sides sandwiching the center in the transverse direction of the tunnel being regarded as a pair of one-side regions (see Figs. 1 and 2). In the center of the transverse direction of the tunnel in the invert section 33, a plurality of H-shaped steels 35 supporting earth retaining plate members and protective fences, etc., for preventing the other one-side region from being affected when constructing the invert structure 10 in each one-side region 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 section 33 with the flanges aligned in the axial direction of the tunnel. For this reason, at the center side of the transverse direction of the tunnel at the position where the H-shaped steels 35 are erected, a pair of PCa concrete blocks (center side blocks) 20B adjacent in the axial direction of the tunnel can have notched recesses 20e having a rectangular cross-sectional shape formed at the corners on both sides sandwiching the gap 21b between them at the end portions on the center side (see Fig. 3). By using the notched recesses 20e at the corner portions on both sides, a flange arrangement recess 10a for arranging one of the flange portions of the H-shaped steel 35 can be provided in the portion where the H-shaped steel 35 is erected, at the end face portion (central end face portion) 10B on the central side in the transverse direction of the tunnel of each invert structure 10.

[0033] That is, in the block group 20X, 20Y (see FIG. 1) consisting of a plurality of PCa concrete blocks 20 constituting the invert structure 10 of each one side region, the PCa concrete block 20 (central side block 20B) arranged in the portion where the H-shaped steel 35 is erected has a curved upper surface portion 20a and a lower surface portion 20b having a curved shape that follows the cross-sectional shape of the invert covering body 32, and is formed as a hexahedral block having a pair of flat axial opposing surfaces 20c at the front and rear and a pair of flat transverse opposing surfaces 20d at the left and right (see FIGS. 6(a) to (c)). At the corner portion between the axial opposing surfaces 20c and the transverse opposing surfaces 20d at any one location, as shown in FIG. 3, a notched recess 20e having a rectangular cross-sectional shape is cut out so as to have a side portion with a width of at least 1 / 2 the width of the flange portion of the H-shaped steel 35, and is continuously provided from the upper surface portion 20a to the lower surface portion 20b (see FIG. 15). As a result, at the central ends of a pair of central side blocks 20B that are adjacent in the axial direction of the tunnel at the portion where the H-shaped steel 35 is erected, these notched recesses 20e form flange arrangement recesses 10a that can accommodate the flange portions of the H-shaped steel 35.

[0034] In this embodiment, as shown in Figures 3 and 4, 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 the adjacent receiving portions 31c and between the 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 the adjacent PCa concrete blocks 20A, 20B, 20C (transverse block rows 20D), and are arranged vertically and horizontally in the invert section 33. The multiple PCa concrete blocks 20A, 20B, 20C used when constructing the invert structure 10 can be constructed by the following method of installing PCa blocks in the invert.

[0035] That is, in the method of installing PCa blocks in the invert section according to this embodiment, the multiple PCa concrete blocks 20A, 20B, 20C of each transverse block row 20D arranged in the transverse direction of the tunnel are installed in the invert section 33 by installing the receiving base side block 20A adjacent to the receiving base section 31c and temporarily fixing it by temporary fixing means 36, as shown in Figure 4, and then installing the intermediate block 20C and the central side block 20B adjacent to the temporarily fixed receiving base side block 20A.

[0036] 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, and then the intermediate block 20C and the central block 20B are installed adjacent to the temporarily fixed receiving base side block 20A, and the adjacent locations of each of these installed blocks 20A, 20B, 20C are temporarily fixed by bolt members (not shown) via bolt boxes 23 arranged on the upper surface 20a of at least one of the PCa concrete blocks 20A, 20B, 20C close to the transverse opposing surface 20d.Then, the height and position of each PCa concrete block 20A, 20B, 20C are adjusted, and the bolt members are finally tightened, thereby installing the multiple PCa concrete blocks 20A, 20B, 20C of each transverse block row 20D arranged in series in the transverse direction of the tunnel in the invert portion 33.

[0037] Also, 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, and 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, and the height and position of each PCa concrete block 20A, 20C are adjusted, and the bolt members are then finally tightened. Next, a central side block 20B is installed adjacent to the intermediate block 20C, and at the adjacent location between the installed central side 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 adjusting the height and position of the central side block 20B, the bolt members are finally tightened, whereby the multiple PCa concrete blocks 20A, 20B, 20C of each transverse block row 20D that are connected in the transverse direction of the tunnel can be installed in the invert portion 33.

[0038] 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.

[0039] 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 Figures 6(a) and 7. 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 that communicate with these gaps 21a, 21b (see FIG. 10), 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.

[0040] As described above, in this embodiment, a nut member is preferably fixed as a female screw member 25a to a portion lower than the vertical middle portion of each bolt insertion screw hole 25, and the height adjustment bolt 26 is screwed into 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 portion 20b of the PCa concrete block 20A, 20B, 20C. A tiltable ground adjuster 26b can be attached to the lower end 26a of the height adjustment bolt 26 (see FIG. 8(a)). The ground adjuster 26b tilts relative to the lower end 26a of the height adjustment bolt 26, so that the adjuster 26b can be tilted along the filling bottom surface portion 26c, for example, the ground surface. This allows the lower end 26a of the height adjustment bolt 26 to be grounded on the filling bottom surface portion 26c below the lower surface portion 20b in a stable state.

[0041] It is preferable that the ground adjuster 26b can be accommodated in the small trumpet-shaped recess 25c, which expands downward when the height adjustment bolt 26 is retracted upward. For example, as shown in FIG. 8(b), by making the small trumpet-shaped recess 25c a trumpet-shaped recess that expands downward and conforms to the outer circumferential shape of the ground adjuster 26b and is slightly larger than the small trumpet-shaped recess, the ground adjuster 26b having a shape similar to that of the small trumpet-shaped recess 25c can be easily accommodated inside the small trumpet-shaped recess 25c without protruding downward from the lower surface portion 20b of the PCa concrete block 20. This makes it possible to make the adjuster 26b ground on the filled bottom surface portion 26c and finely adjust the height of the PCa concrete block 20, even if the gap 21c between the lower surface portion 20b of the PCa concrete block 20 and the filled bottom surface portion 26c is not sufficient to meet the height of the ground adjuster 26b. Furthermore, since the height position of the filled bottom portion 26c after leveling is the same height as the designed position of the lower surface portion 20b of the PCa concrete block 20, even if there is no room for maneuver, the entire ground contact adjuster 26b can be accommodated in the small trumpet-shaped recess 25c and each PCa concrete block 20 can be installed in a predetermined position with the lower surface portions 20b abutting against the filled bottom portion 26c.

[0042] The small trumpet-shaped recess 25c preferably has a height from the opening in the lower surface 20b of the PCa concrete block 20 to the lower end of the female screw member 25a of about 60 to 80 mm, and an opening diameter in the lower surface 20b of about 65 to 70 mm. The taper gradient of the small trumpet-shaped recess 25c is preferably inclined by 10% or more with respect to the central axis of the bolt insertion screw hole 25 from the viewpoint of facilitating removal of the box punch member after the concrete has hardened.

[0043] 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.

[0044] It is preferable that the large trumpet-shaped recess 25b has a height from the opening in the upper surface 20a of the PCa concrete block 20 to the upper end of the female screw member 25a of about 360 to 380 mm, and an opening diameter in the upper surface 20a of about 106 to 110 mm. The taper gradient of the large trumpet-shaped recess 25b is preferably inclined by 10% or more with respect to the central axis of the bolt insertion screw hole 25 from the viewpoint of facilitating removal of the box punch member after the concrete has hardened.

[0045] In this embodiment, as described above, each of the PCa concrete blocks 20A, 20B, 20C has three bolt insertion holes 25 formed vertically, and a height adjustment bolt 26 is attached to each of the bolt insertion holes 25 in a state in which the protruding length of the lower end 26a protruding downward from the lower surface 20b of the PCa concrete blocks 20A, 20B, 20C can be adjusted. As a result, prior to the process of filling the filling solidification material 22 into the gaps 21a between the adjacent receiving base parts 31c of the multiple PCa concrete blocks 20A, 20B, 20C arranged vertically and horizontally, the gaps 21b between the adjacent PCa concrete blocks 20A, 20B, 20C, and the gaps 21c below the hexahedral lower surface parts 20b communicating with these gaps 21a and 21b, the gaps 21a between the adjacent receiving base parts 31c of the multiple PCa concrete blocks 20A, 20B, 20C arranged vertically and horizontally, and the gaps 21c below the hexahedral lower surface parts 20b communicating with these gaps 21a and 21b, the gaps 21b between the adjacent receiving base parts 31c of the multiple PCa concrete blocks 20A, 20B, 20C arranged vertically and horizontally, The gap width b (see Figs. 7 and 10) of the gap 21c below the hexahedral bottom surface 20b of the PCa concrete blocks 20A, 20B, and 20C is measured from the protruding length of the lower end 26a of the height adjustment bolt 26 protruding from the bottom surface 20b of the PCa concrete blocks 20A, 20B, and 20C, and the planned amount of filling solidification material 22 to be filled in the gap 21c below the hexahedral bottom surface 20b can be calculated in advance based on this and the area of ​​the bottom surface 20b of the PCa concrete blocks 20A, 20B, and 20C. In the process of filling the filling solidification material 22, a predetermined amount of the filling solidification material 22 is injected into the gap 21c below the hexahedral bottom surface 20b in consideration of the calculated planned filling amount, and is filled and hardened.

[0046] That is, in this embodiment, the nut member 25a is fixed as a female screw member to a portion lower than the vertical middle portion of each bolt insertion screw hole 25, and the height adjustment bolt 26 is screwed into the nut member 25a, so that the protruding length of the lower end 26a of the height adjustment bolt 26 from the lower surface portion 20b of the PCa concrete block 20A, 20B, 20C can be adjusted by the height adjustment bolt 26 being attached in such a manner that the protruding length of the lower end 26a from the lower surface portion 20b of the PCa concrete block 20A, 20B, 20C can be adjusted. Therefore, for example, when the lower end 26a of the height adjustment bolt 26 is grounded to the filling bottom surface portion 26c below the hexahedral lower surface portion 20b, the gap width b of the gap 21c below the hexahedral lower surface portion 20b can be easily measured from the length of the height adjustment bolt 26 above the nut member 25a.

[0047] Furthermore, in this embodiment, a tiltable ground adjuster 26b is preferably attached to the lower end 26a of the height adjustment bolt 26, so that when the ground adjuster 26b is grounded to the filled bottom surface portion 26c below the hexahedral lower surface portion 20b, the gap width b of the gap 21c below the hexahedral lower surface portion 20b can be easily measured in a more stable state from the length of the height adjustment bolt 26 above the nut member 25a.

[0048] The planned amount of filling solidification material 22 can be calculated in advance by calculating the amount of filling material to be filled in the gaps 21c below the hexahedral underside 20b of each of the PCa concrete blocks 20A, 20B, and 20C based on the average of the gap width b of the gaps 21c below the hexahedral underside 20b measured by three height adjustment bolts 26 attached to the three bolt insertion screw holes 25 of each of the PCa concrete blocks 20A, 20B, and 20C.

[0049] In addition, the planned amount of filling solidification material 22 can also be calculated in advance by calculating the amount of filling to be filled in the gaps below the hexahedral underside portions 20b of the PCa concrete blocks 20A, 20B, and 20C throughout the entire invert structure 10 based on the overall average of the gap width b of the gaps 21c below the hexahedral underside portions 20b, each measured by three height adjustment bolts 26 attached to three bolt insertion screw holes 25 of each of the PCa concrete blocks 20A, 20B, and 20C that constitute the invert structure 10.

[0050] Furthermore, in this embodiment, in the invert structure 10 using the above-mentioned PCa concrete blocks 20A, 20B, 20C, the following construction method can be adopted as a method for connecting the multiple PCa concrete blocks 20A, 20B, 20C vertically and horizontally and installing them as a single unit in the invert section 33 while maintaining gaps 21b of a predetermined spacing width between adjacent PCa concrete blocks 20A, 20B, 20C.

[0051] That is, in this embodiment, as shown in Figures 3, 4, and 6(a) to (c), the construction method for connecting and installing the PCa concrete blocks 20A, 20B, and 20C in the invert section structure 10 is 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 6(b)) fixed to one of the opposing surfaces are disposed, preferably at least in three places, and the pair of PCa concrete blocks 20A, 20B, and 20C adjacent to each other in the transverse direction of the tunnel are connected with a gap 21b of a predetermined interval between the transverse opposing surfaces 20d by the fastening force of bolt members (not shown) fastened by bolt boxes 23 disposed 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. 6(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.

[0052] 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.

[0053] The transverse spacer jigs 29a and the axial spacer jigs 29b, which are preferably arranged at at least three places and fixed to either one of the transverse facing surfaces 20d or the axial facing surfaces 20c, are preferably fixed to at least two places in the region below the center of gravity of the PCa concrete blocks 20A, 20B, and 20C. This makes it possible to form the gaps 21a and 21b of a predetermined interval width in a stable and accurate manner in the region below the center of gravity, where it is difficult to confirm that the gaps 21a and 21b have been formed accurately, without using any special device, when installing the PCa concrete blocks 20A, 20B, and 20C.

[0054] The bolt member fastened in the bolt box 23 arranged on the upper surface 20a of at least one of the PCa concrete blocks 20A, 20B, 20C adjacent to the transverse opposing surface 20d, or the bolt member fastened in the bolt box 23 arranged on the upper surface 20a of at least one of the PCa concrete blocks 20A, 20B, 20C adjacent to the axial opposing surface 20c, may preferably be fastened across the bolt box 23 arranged on the upper surface 20a adjacent to the axial opposing surface 20c or the transverse opposing surface 20d of one of the PCa concrete blocks 20A, 20B, 20C and the female thread anchor 24 embedded in the axial opposing surface 20c or the transverse opposing surface 20d of the other PCa concrete block 20A, 20B, 20C. Preferably, the bolt box 23 may be fastened across and between the bolt box 23 arranged on the upper surface 20a adjacent to the axial opposing surface 20c or the transverse opposing surface 20d of one PCa concrete block 20A, 20B, 20C and the bolt box 23 arranged on the upper surface 20a adjacent to the axial opposing surface 20c or the transverse opposing surface 20d of the other PCa concrete block 20A, 20B, 20C.

[0055] In this embodiment, as shown in Figure 9(a), when a mountain tunnel includes a portion with a tunnel line shape that curves horizontally, multiple PCa concrete blocks 20A, 20B, 20C can be connected vertically and horizontally and installed as a single unit in the inverter section 33, while maintaining gaps 21b of a predetermined spacing width between adjacent PCa concrete blocks 20A, 20B, 20C and aligning them along the tunnel line shape S1 that curves horizontally.

[0056] That is, in this embodiment, between each pair of transverse opposing surfaces 20d of the PCa concrete blocks 20A, 20B, 20C adjacent in the transverse direction of the tunnel, transverse spacer jigs 29a (see Figure 6(b)) fixed to one of the transverse opposing surfaces 20d are arranged in at least three locations and interposed, and each pair of PCa concrete blocks 20A, 20B, 20C adjacent in the transverse direction of the tunnel are connected by the fastening force of bolt members (not shown) while maintaining a gap 21b of a predetermined spacing width between the transverse opposing surfaces 20d, thereby forming a transverse block row 20D made up of a plurality of PCa concrete blocks 20A, 20B, 20C (see Figure 3). Between each pair of axially opposing surfaces 20c of the PCa concrete blocks 20A, 20B, 20C adjacent to each other in the axial direction of the tunnel, axial spacer jigs 29b (see Figure 6(c)) fixed to one of the axially opposing surfaces 20c are arranged in at least three locations, and each pair of PCa concrete blocks 20A, 20B, 20C adjacent to each other in the axial direction of the tunnel are connected by the fastening force of bolt members (not shown) while maintaining a gap 21b of a predetermined spacing width between the axially opposing surfaces 20c (see Figure 3). 9(a), in one or more axial connection parts 20f between the transverse block rows 20D arranged in a row in the axial direction of the tunnel, the axial spacer jigs 29b interposed between a pair of axially opposed surfaces 20c in the axial direction of the tunnel are fixed to the axially opposed surfaces 20c in a state in which the intervening width is adjusted so that the width of the outer gap 21b held by the axial spacer jigs 29b fixed to the outer PCa concrete block 20E located outside the tunnel linear shape S1 curved in the horizontal direction in the transverse direction of the tunnel is larger than the width of the inner gap 21b held by the axial spacer jigs 29b fixed to the inner PCa concrete block 20F located inside the tunnel linear shape S1 curved in the horizontal direction. This makes it possible to install the multiple PCa concrete blocks 20A, 20B, 20C in the invert section 33 by connecting them vertically and horizontally along the tunnel linear shape S1 curved in the horizontal direction.This also makes it possible to use rectangular PCa concrete blocks 20A, 20B, 20C to accommodate a tunnel linear shape that curves in the horizontal direction, without using tapered blocks.

[0057] Here, in this embodiment, as described later, the invert structure 10 is constructed in each of the regions on either side of the transverse center line C of the mountain tunnel 30 (see FIG. 1). In FIG. 9(a), the block row 20D is illustrated as a block row 20D that is continuous with one another in the invert lining body 32, in which the transverse block row 20D of the one-side block group 20X in the invert structure 10 in one side region and the transverse block row 20D of the other-side block group 20Y in the invert structure 10 in the other side region are integrated together. However, in this embodiment, the block groups 20X, 20Y in each of the one side region and the other side region are arranged in a plurality of consecutive rows in the axial direction of the tunnel. In one or more axial connecting portions 20f of the tunnel between the transverse block rows 20D, the size and protruding length of the axial spacer jig 29b interposed between a pair of axial opposing surfaces 20c in the axial direction of the tunnel is adjusted so that the spacing width of the outer gap 21b maintained by the axial spacer jig 29b fixed to the outer PCa concrete block 20E located on the outside of the horizontally curved tunnel linear shape S1 in the transverse direction of the tunnel is larger than the spacing width of the inner gap 21b maintained by the axial spacer jig 29b fixed to the inner PCa concrete block 20F located on the inside of the horizontally curved tunnel linear shape S1.

[0058] In addition, in relation to this, it is preferable to adjust the size and protruding length of the multiple axial spacer jigs 29b interposed between each pair of axially opposing surfaces 20c of each PCa concrete block 20A, 20B, 20C that constitute a pair of transverse block rows 20D connected at the connecting portion 20f, so that the spacing width of the outer portion of the horizontally curved tunnel linear shape S1 in the gap 21b between each pair of adjacent PCa concrete blocks 20A, 20B, 20C is larger than the spacing width of the inner portion.

[0059] In addition, when the axial spacer jig 29b is made of a mortar block that is attached and fixed to one of the axial opposing surfaces 20c, the spacing width can be adjusted so that the gap width of the outer gap 21b is larger than the gap width of the inner gap 21b by fixing mortar blocks of different sizes to the outer PCa concrete block 20E and the inner PCa concrete block 20F at the connecting portion 20f where the spacing width is different.

[0060] Furthermore, when the axial spacer jig 29b is made of a male threaded member fixed so that the protruding length can be adjusted by being screwed into a female threaded insert embedded in one of the axial opposing surfaces 20c, the male threaded member can be screwed and fixed with different screwing amounts in the outer PCa concrete block 20E and the inner PCa concrete block 20F at the connecting portion 20f, which has a different spacing width, so that the spacing width of the outer gap 21b is larger than the spacing width of the inner gap 21b.

[0061] On the other hand, in this embodiment, when the mountain tunnel includes a portion with a tunnel linear shape that curves in the vertical direction, the block connection structure 70 in the invert section structure of this embodiment enables multiple PCa concrete blocks 20A, 20B, 20C to be connected vertically and horizontally and installed as a single unit in the invert section 33, while maintaining gaps 21b of a predetermined spacing width between adjacent PCa concrete blocks 20A, 20B, 20C, and aligning them along the tunnel linear shape that curves in the vertical direction (vertical direction).

[0062] That is, in this embodiment, as described above, between each pair of transverse opposing surfaces 20d of the PCa concrete blocks 20A, 20B, 20C adjacent in the transverse direction of the tunnel, transverse spacer jigs 29a (see Figure 6(b)) fixed to one of the transverse opposing surfaces 20d are arranged in at least three locations and interposed, and each pair of PCa concrete blocks 20A, 20B, 20C adjacent in the transverse direction of the tunnel are connected by the fastening force of bolt members (not shown) while maintaining a gap 21b of a predetermined spacing width between the transverse opposing surfaces 20d, thereby forming a transverse block row 20D made up of a plurality of PCa concrete blocks 20A, 20B, 20C (see Figure 3). Between each pair of axially opposing surfaces 20c of adjacent PCa concrete blocks 20A, 20B, 20C facing in the axial direction of the tunnel, axial spacer jigs 29b (see Figure 6(c)) fixed to one of the axially opposing surfaces 20c are arranged in at least three locations, and each pair of PCa concrete blocks 20A, 20B, 20C adjacent in the axial direction of the tunnel are connected by the fastening force of bolt members (not shown) while maintaining a gap 21b of a predetermined spacing width between the axially opposing surfaces 20c. 9(b), in one or more axial connection parts 20g between the transverse block rows 20D arranged in the axial direction of the tunnel, at least three axial spacer jigs 29b interposed between each pair of axially opposed surfaces 20c facing each other in the axial direction of the tunnel are fixed to the axially opposed surfaces 20c in a state in which the intervening width is adjusted so that the gap width of the upper gap 21b held by the axial spacer jigs 29b arranged in the upper stage and the gap width of the lower gap 21b held by the axial spacer jigs 29b arranged in the lower stage are different. This makes it possible to install the multiple PCa concrete blocks 20A, 20B, 20C in the invert section 33 as a whole by connecting them vertically and horizontally along the tunnel linear curve.This also makes it possible to use rectangular PCa concrete blocks 20A, 20B, 20C to accommodate a tunnel linear shape that curves in the vertical direction, without using tapered blocks.

[0063] For example, by adjusting the spacing widths in connecting portions 20g having different spacing widths so that the spacing width of the upper gap 21b held by the axial spacer jig 29b arranged in the upper tier is larger than the spacing width of the lower gap 21b held by the axial spacer jig 29b arranged in the lower tier, it becomes possible to arrange multiple adjacent transverse block rows 20D along the tunnel linear shape that curves downward in the vertical direction.

[0064] Furthermore, by adjusting the spacing widths at connecting portions 20g having different spacing widths so that the spacing width of the upper gap 21b held by the axial spacer jig 29b arranged in the upper tier is smaller than the spacing width of the lower gap 21b held by the axial spacer jig 29b arranged in the lower tier, it is possible to arrange multiple adjacent transverse block rows 20D along a tunnel linear shape that curves upward in the vertical direction.

[0065] Here, when the axial spacer jig 29b is made of mortar blocks attached and fixed to one of the axial opposing surfaces 20c, the spacing width can be adjusted so that the spacing width of the gap 21b held at the upper part and the spacing width of the gap 21b held at the lower part are different widths by fixing mortar blocks of different sizes to the upper and lower rows at the connecting portion 20g where the spacing width is different.

[0066] Furthermore, when the axial spacer jig 29b is made of a male screw member fixed so that the protruding length can be adjusted by being screwed into a female screw insert embedded in one of the axial opposing surfaces 20c, the male screw member can be screwed and fixed with different screwing amounts in the upper and lower stages at the connecting portion 20g having different spacing widths, thereby making it possible to adjust the spacing width so that the spacing width of the gap 21b held at the upper part and the spacing width of the gap 21b held at the lower part are different widths.

[0067] In this embodiment, the PCa concrete blocks 20A, 20B, and 20C arranged in a row and column are integrated through the filling solidification material 22 filled and hardened 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 bottom surface portion communicating with these gaps, as shown in Fig. 10, to form at least a part of the invert section covering body 32. In this embodiment, the filling solidification material 22 is 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 bottom surface portion communicating with these gaps, by the following construction method.

[0068] That is, in this embodiment, in the process of filling the filling solidification material 22 into the gaps 21a between adjacent receiving portions 31c of multiple PCa concrete blocks 20A, 20B, 20C arranged in a row and column, the gaps 21b between adjacent PCa concrete blocks 20A, 20B, 20C, and the gaps 21c below the hexahedral lower surface portions communicating with these gaps 21a, 21b, the opening portions of the gaps 21a, 21b opening in the upper surface portions 20a, gable end surface portions 10A (see Figures 3 and 12), and center end surface portions 10B (see Figures 3 and 12) of the multiple PCa concrete blocks 20A, 20B, 20C arranged in a row and column are kept in a blocked state. Thereafter, as shown in Fig. 10 to Fig. 12, the filling solidification material 22 is sequentially injected from the filling material injection hole 27d on the center side, which is provided to penetrate vertically into one or more of the multiple central side blocks 20B arranged in series in the axial direction of the tunnel, and from the filling material injection hole 27e on the receiving side, which is provided to penetrate vertically into one or more of the multiple receiving base side blocks 20A arranged in series in the axial direction of the tunnel. Preferably, as shown in Fig. 12, the injection of the filling solidification material 22 is started from the filling material injection hole 27d on the center side, and then the filling material injection hole 27e on the receiving base 31c side is switched to inject the filling solidification material 22 further, and then the filling of the filling solidification material 22 is completed when it is confirmed that the filling solidification material 22 flows out from the opening of the gap 21a between the receiving base 31c held on the upper surface 20a of the receiving base side block 20A. It is also possible to inject the filling solidification material 22 using only the filler injection hole 27d of the center side block 20B without using the filler injection hole 27e of the receiving base side block 20A, and to finish filling the filling solidification material 22 when it is confirmed that the filling solidification material 22 flows out from the opening of the gap 21a between the receiving base 31c held on the upper surface 20a of the receiving base side block 20A.

[0069] In this embodiment, the multiple PCa concrete blocks 20A, 20B, 20C arranged in a row are preferably adjacent to the axial direction of the tunnel of the existing invert structure 40 (see Figs. 3 and 12) formed in advance. In a state where the opening portion of the gap 21d between the upper surface 20a of the multiple PCa concrete blocks 20A, 20B, 20C arranged in a row and the existing invert structure 40, which opens at the center end surface 10B, is blocked, the filling solidification material 22 is injected while switching from the filling material injection hole 27d on the center side located on the existing invert structure 40 side to the filling material injection hole 27d on the center side located on the gable side, as shown in Fig. 12, and the filling solidification material 22 is injected while switching from the filling material injection hole 27e on the receiving base side located on the existing invert structure 50 side to the filling material injection hole 27e on the receiving base side located on the gable side. It is also possible to switch from the filler injection hole 27d of the central side block 20B on the existing invert section structure 50 side to the filler injection hole 27d of the central side block 20B on the gable side and halfway inject the filling solidification material 22, and then switch again from the filler injection hole 27e of the receiving base side block 20A on the existing invert section structure 50 side to the filler injection hole 27e of the receiving base side block 20A on the gable side to inject the filling solidification material 22.

[0070] Furthermore, in this embodiment, the upper surface band plate-shaped formwork 41a is attached to the upper surface 20a of the multiple PCa concrete blocks 20A, 20B, 20C arranged vertically and horizontally so as to cover the openings of the gaps 21b in the upper surface 20a, thereby blocking the openings of the upper surface 20a (see Figs. 10 and 13). In the end surface 10A, the end band plate-shaped formwork 41b is attached to the end surface 10A so as to cover the openings of the gaps 21a, 21b, 21c, thereby blocking the openings of the end surface 10A (see Fig. 14). As with the gable side end surface portion 10A, the central side band plate-shaped formwork 41c is overlapped and fixed to the central side end surface portion 10B, preferably so as to cover the openings of the gaps 21b, 21c, and 21d, thereby blocking the openings of the central side end surface portion 10B (see Figure 10).

[0071] In addition, the upper surface band plate formwork 41a, the gable portion band plate formwork 41b, and the center side band plate formwork 41c are preferably formed using transparent plate members, so that the filling status of the filling solidification material 22 in each of the gaps 21a, 21b, 21c, and 21d can be visually confirmed through these transparent band plate formworks.

[0072] Furthermore, it is preferable to attach an air vent hose 42 (see FIG. 10) extending from an appropriate position to the upper surface band plate formwork 41a attached so as to cover the openings of the gaps 21a, 21b, 21d in the upper surface 20a of the multiple PCa concrete blocks 20A, 20B, 20C arranged vertically and horizontally. This makes it possible to effectively vent air from the gaps 21a, 21b, 21d via the air vent hose 42 when the filling solidification material 22 is filled, and it is also possible to confirm that the filling solidification material 22 has been filled by flowing out of the air vent hose 42.

[0073] In this embodiment, in the process of filling the gaps 21a between the adjacent receiving base portions 31c of the multiple PCa concrete blocks 20A, 20B, 20C arranged in a row vertically and horizontally, the gaps 21b between the adjacent PCa concrete blocks 20A, 20B, 20C, and the gaps 21c below the hexahedral bottom surfaces communicating with the gaps 21a and 21b, as described above, the upper surfaces 20a and With the openings of the gaps 21a, 21b, 21c at the end face 10A and the center face 10B closed, the filling solidification material 22 is sequentially injected from the center-side filler injection hole 27d provided vertically penetrating one or more of the center-side blocks 20B arranged adjacent to each other in the axial direction of the tunnel, and from the receiving-side filler injection hole 27e provided vertically penetrating one or more of the receiving-side blocks 20A arranged adjacent to each other in the axial direction of the tunnel. An open / close valve member 28 that can be opened and closed is attached to the center-side filler injection hole 27d and the receiving-side filler injection hole 27e, respectively. When filling solidification material 22 is filled by sequentially connecting an injection hose to the opening and closing valve member 28 of the selected filling material injection hole 27d on the center side or the filling material injection hole 27e on the pedestal side, the opening and closing valve member 28 of the filling material injection hole 27d on the center side or the filling material injection hole 27e on the pedestal side is closed after filling is completed. The opening and closing valve member 28 of the unused filling material injection hole 27d on the center side or the filling material injection hole 27e on the pedestal side is left open and can be used as an air bleeding member. As described above, in the process of filling the filling solidification material 22, the filling solidification material 22 can be injected using only the filling material injection hole 27d of the center side block 20B, without using the filling material injection hole 27e of the receiving base side block 20A, and the filling of the filling solidification material 22 can be completed when it is confirmed that the filling solidification material 22 flows out from the opening of the gap 21a between the receiving base 31c held on the upper surface 20a of the receiving base side block 20A.By filling the filling solidification material 22 through the filling material injection hole 27d on the central side, air can be smoothly removed from the gap 21a between the receiving base 31c held on the upper surface 20a of the receiving base side block 20A, making it possible to effectively prevent air from collecting in the filled filling solidification material 22.

[0074] In addition, in this embodiment, the multiple PCa concrete blocks 20A, 20B, 20C arranged in a row vertically and horizontally are preferably arranged adjacent to each other in the axial direction of the tunnel of the existing invert structure 40 formed in advance, as described above, and in a state where the opening portion of the gap 21d between the existing invert structure 40 and the upper surface portion 20a and the central end surface portion 10B of the multiple PCa concrete blocks 20A, 20B, 20C arranged in a row vertically and horizontally is closed, The filling solidification material 22 is injected by switching from the opening / closing valve member 28 of the filling material injection hole 27d on the central side located on the existing invert section structure 40 side to the opening / closing valve member 28 of the filling material injection hole 27d on the central side located on the gable side, and the filling solidification material 22 is injected by switching from the opening / closing valve member 28 of the filling material injection hole 27e on the receiving base side located on the existing invert section structure 40 side to the opening / closing valve member 28 of the filling material injection hole 27e on the receiving base side located on the gable side. As described above, it is also possible to switch from the filler injection hole 27d of the central side block 20B on the existing invert section structure 50 side to the filler injection hole 27d of the central side block 20B on the gable side to halfway inject the filling solidification material 22, and then switch further from the filler injection hole 27e of the receiving base side block 20A on the existing invert section structure 50 side to the filler injection hole 27e of the receiving base side block 20A on the gable side to inject the filling solidification material 22.

[0075] In each of the central filler injection holes 27d and the pedestal filler injection holes 27e, the open / close valve members 28 can be attached in a state of protruding upward from the upper surface of the multiple PCa concrete blocks 20A, 20B arranged vertically and horizontally by screwing the male screw portion 28b into the female screw member 27a fixed to the middle portion in the penetration direction of the central filler injection holes 27d or the pedestal filler injection holes 27e, as described above. This makes it possible to easily perform the operation of detachably connecting the injection hose by working on the upper surface 20a of the PCa concrete blocks 20A, 20B, 20C.

[0076] In this embodiment, the invert structure 10 having the above-mentioned configuration is constructed in each of a pair of side regions, each of which is formed by sandwiching the center of the tunnel in the transverse direction, as shown in Figures 1 and 2, so that together they can form the invert structure 50 covering the entire transverse area, which constitutes the invert covering body 32.

[0077] 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 Fig. 1 and Fig. 2, in each of one side region and the other side region 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 section 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 filling solidification material 22 that has been filled and hardened 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.

[0078] 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.

[0079] 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.

[0080] Furthermore, in this embodiment, it is preferable that the central side surface of the PCa concrete block (central side block) 20B located most centrally of the one side block group 20X, which faces the gap portion 51, and the central side surface of the PCa concrete block (central side block) 20B located most centrally of the other side block group, are provided with irregularities 52 for improving adhesion with the filling solidification material 22, as shown in Figure 15, for example.

[0081] The unevenness 52 for improving the adhesion with the filling solidification material 22 can also be formed on the transverse facing surfaces 20d facing each other across the held gaps 21a, 21b of each PCa concrete block 20 arranged in series in the transverse direction of the tunnel and installed in the invert section 33, preferably with the gaps 21a, 21b held between the receiving base 31c at the lower end of the adjacent side wall lining body 31a and between the adjacent PCa concrete blocks 20. The unevenness 52 for improving the adhesion with the filling solidification material 22 can also be formed on the axial facing surfaces 20c facing each other across the held gaps 21b of each PCa concrete block 20 arranged in series in the axial direction of the tunnel and installed in the invert section 33, preferably with the gaps 21b held between the adjacent PCa concrete blocks 20.

[0082] In this embodiment, the PCa concrete block (center-side block) 20B located at the most central side of the one-side block group 20X and the PCa concrete block (center-side block) 20B located at the most central side of the other-side block group 20Y are preferably connected via long bolt members (not shown). This makes it possible to ensure the installation accuracy of the one-side block group 20X and the other-side block group 20Y, and also to ensure the shear strength of the portion between these block groups 20X and 20Y.

[0083] In this embodiment, the invert structure 50 over the entire transverse area of ​​the above-mentioned tunnel can be formed by the following construction method. That is, in this embodiment, the construction method of the invert structure 50 includes a step of arranging a plurality of PCa concrete blocks 20A, 20B, 20C in a row in the transverse direction of the tunnel and installing them in the invert portion 33 in a state in which gaps 21a, 21b are maintained between the adjacent PCa concrete blocks 20A, 20B, 20C and the receiving base portions 31c at the lower ends of the adjacent side wall lining bodies 31a and between the adjacent PCa concrete blocks 20A, 20B, 20C in one side region in the transverse direction of the tunnel, and arranging the plurality of PCa concrete blocks 20A, 20B, 20C in a row in the transverse direction of the tunnel and installing them in the invert portion 33 in a state in which gaps 21a, 21b are maintained between the adjacent PCa concrete blocks 20A, 20B, 20C in the axial direction of the tunnel, thereby forming one side block group 20X; and a process of filling and hardening a filling solidification material 22 into a gap 21c below the lower surface of the hexahedron shaped block 31a and communicating with the blocks 31a and 31b, and arranging a plurality of PCa concrete blocks 20A, 20B, and 20C in a row in the transverse direction of the tunnel and installing them in an invert section 33 in a state in which gaps 21a and 21b are maintained between the receiving base section 31c at the lower end of the adjacent side wall lining body 31a and between the adjacent PCa concrete blocks 20A, 20B, and 20C in the other side region in the transverse direction of the tunnel. and a step of forming the other side block group 20Y by arranging the PCa concrete blocks 20A, 20B, 20C in series and installing them on the invert portion 33 while maintaining gaps 21b between the adjacent PCa concrete blocks 20A, 20B, 20C in the axial direction of the tunnel as well.The process includes filling and hardening the filling solidification material 22 in the gap 51 between the block group 20X on one side and the block group 20Y on the other side, in addition to the gap 21b between the block group 20X on one side and the gap 21c below the bottom surface of the hexahedron that communicates with these, and thereby makes it possible to easily form the invert structure 50 that is provided across the entire transverse area of ​​the tunnel and that constitutes the invert covering body 32.

[0084] The invert structure 50 over the entire transverse area can be formed by constructing both sides simultaneously, rather than constructing each side area at a time, for example, when construction can be carried out by blocking traffic through the mountain tunnel 30 for an extended period of time.

[0085] Furthermore, according to the invert structure 10 using the PCa block connecting structure of this embodiment having the above-mentioned configuration, by using PCa concrete blocks 20 (20A, 20B, 20C) of appropriate weight and size that can be easily manufactured in a factory, etc., the blocks can be easily formed without much effort, and can be more quickly installed as a component part of the invert lining body 32 that is provided in continuity with the lining body 31 of the upper arch-shaped portion 31b from the tunnel side wall portion 31a.

[0086] That is, according to this embodiment, the invert structure 10 is formed such that the PCa concrete block 20 constituting the invert structure has a hexahedral shape with a curved upper surface portion 20a and a curved lower surface portion 20b, for example, 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, and has a weight of about 1300 kg. Compared to conventional concrete members for inverts made of precast concrete, which are heavy and complex in shape, the PCa concrete block 20 has a moderate weight, size, and shape, which allows for efficient manufacturing, improves workability during lifting and transportation, and By improving ease of handling when lifting and installing, it becomes possible to precisely install each PCa concrete block 20 at a specified interval in a predetermined position. Furthermore, by the simple task of injecting a filling material into the gaps and spaces between the PCa concrete blocks 20 installed adjacent to each other vertically and horizontally and allowing it to harden, these PCa concrete blocks 20 can be firmly integrated together, making it easy to form the structure. This makes it possible to install the PCa concrete blocks 20 more quickly and easily as part of the invert lining 32 that is provided in continuity with the lining 31 from the tunnel side wall 31a to the upper arch-shaped portion 31b.

[0087] In addition, according to the block connection structure 70 of this embodiment, in the axial connection portions 20g of one or more tunnels between a plurality of transverse block rows 20D arranged in the axial direction of the tunnel, at least three axial spacer jigs 29b interposed between each axial opposing surface 20c facing the tunnel axial direction are fixed to the axial opposing surfaces 20c with the interposition width adjusted so that the spacing width of the upper gap 21b held by the axial spacer jig 29b arranged in the upper stage and the spacing width of the lower gap 21b held by the axial spacer jig 29b arranged in the lower stage are different widths. Therefore, it becomes possible to easily form the invert section structure 11, which is a component part of the above-mentioned invert section covering body 32, in accordance with the tunnel linear shape S2 curved in the vertical direction.

[0088] The present invention is not limited to the above embodiment and can be modified in various ways. For example, the invert structure is not limited to construction work for extending the lining to the invert of a mountain tunnel in which the lining covering the inner wall surface of the tunnel is formed only in the region from the side walls on both sides to the upper arch-shaped portion and is not formed in the invert, but can also be used in construction work for providing a lining around the entire circumference of the inner wall surface of the tunnel, including the invert, when forming a new mountain tunnel, or in construction work for repairing the lining of the invert already provided in the mountain tunnel and re-installing a new lining of the invert. [Explanation of symbols]

[0089] 10 Inverter structure 10a Flange mounting recess 10A End face on the side 10B Center side end section 20,20' PCa concrete block 20a Top part 20b Bottom part 20c Axial opposing surface 20d Transverse facing surface 20e Notch recess 20f, 20g Axial connection part 20A Receiving block side 20B Center side block 20C Middle block 20D Transverse Block Row 20E External PCa concrete block 20F Inner PCa concrete block 20X One-sided block group 20Y Other side block group 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 25a Female screw member (nut member) 25b Large trumpet-shaped recess 25c Small trumpet-shaped recess 26 Height adjustment bolt 26a Lower end 26b Grounding adjuster 26c Filled bottom part 26d Upper end 27 Filler injection hole 27a Female thread member 27b Upper trumpet-shaped recess 27c Lower trumpet-shaped recess 27d Filler injection hole on the center side 27e Filler injection hole on the support side 28 Opening and closing valve parts 28a Handle 29a Transverse spacer fixture 29b Axial spacer jig 29c Hanging jig 30 Mountain Tunnel 30a Bottom panel part 31 Lining body 31a Side wall (side wall lining) 31b Arch-shaped part 31c pedestal part 32 Invert section lining 33 Inverter 35 H type steel 36 Temporary fixing means 36a Hole in Anchor 36b striae 36c Telescopic adjustment means 37 PCa block joint structure 40 Existing invert structure 41a Upper surface band plate formwork 41b Gable section strip formwork 41c Central side strip plate formwork 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 70 Block connection structure S1 Tunnel alignment curved in horizontal direction S2 Vertically curved tunnel alignment

Claims

1. In an invert section structure using PCa concrete blocks that constitutes an invert section lining formed in the invert section of a mountain tunnel, a plurality of PCa concrete blocks are connected vertically and horizontally while maintaining a predetermined gap width between adjacent PCa concrete blocks and aligning them with the tunnel linear shape that curves in the vertical direction, and the structure is for connecting the blocks in the invert section structure to be installed integrally in the invert section, Each of the PCa concrete blocks 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, Between each pair of transverse opposing faces of the PCa concrete blocks adjacent in the transverse direction of the tunnel, transverse spacer jigs fixed to one of the transverse opposing faces are arranged in at least three locations, and each pair of the PCa concrete blocks adjacent in the transverse direction of the tunnel are connected by the fastening force of bolt members while maintaining a gap of a predetermined interval width between the transverse opposing faces, thereby forming a transverse block row made of a plurality of the PCa concrete blocks, Between each pair of axially opposing faces of the PCa concrete blocks adjacent in the axial direction of the tunnel, axial spacer jigs fixed to one of the axially opposing faces are arranged in at least three locations, and each pair of PCa concrete blocks adjacent in the axial direction of the tunnel is connected by the fastening force of bolt members while maintaining a gap of a predetermined interval width between the axially opposing faces. In addition, in the axial connection portion of one or more tunnels between a plurality of transverse block rows arranged in the axial direction of the tunnel, the at least three axial spacer jigs interposed between each of the axial opposing surfaces facing each other in the axial direction of the tunnel are fixed to the axial opposing surfaces with the interposition width adjusted so that the spacing width of the upper gap held by the axial spacer jig arranged in the upper row and the spacing width of the lower gap held by the axial spacer jig arranged in the lower row are different widths.

2. 2. A block connection structure in an inverter structure as described in claim 1, wherein the spacing width is adjusted so that the spacing width of the upper gap held by the axial spacer jig arranged in the upper tier is larger than the spacing width of the lower gap held by the axial spacer jig arranged in the lower tier, thereby making it possible to arrange multiple adjacent widthwise block rows along the tunnel linear shape that curves downward in the vertical direction.

3. The intervening widths are adjusted so that the spacing width of the upper gap held by the axial spacer jig arranged in the upper tier is smaller than the spacing width of the lower gap held by the axial spacer jig arranged in the lower tier, thereby making it possible to arrange the multiple adjacent transverse block rows along the tunnel linear shape that curves upward in the vertical direction. This is a block connection structure in an inverter structure as described in claim 1.

4. The axial spacer jig is made of a mortar block attached and fixed to one of the axial opposing surfaces, and by fixing mortar blocks of different sizes to the upper and lower rows, the spacing width can be adjusted so that the spacing width of the gap held at the upper part and the spacing width of the gap held at the lower part are different widths.This is a block connection structure in an inverter structure described in any one of claims 1 to 3.

5. The axial spacer jig is made of a male threaded member fixed so that the protruding length can be adjusted by screwing it into a female threaded insert embedded in one of the axial opposing surfaces, and the male threaded member is screwed and fixed with different screwing amounts in the upper and lower stages, so that the spacing width can be adjusted so that the spacing width of the gap held in the upper part and the spacing width of the gap held in the lower part are different widths.This is a block connection structure in an inverter structure described in any one of claims 1 to 3.

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