PCa concrete block for inverter unit structure

Abstract

To provide a PCa concrete block for an invert part structure, which enables an invert part to be highly precisely and easily formed so that an upper face is convex downward and flush curved surface.SOLUTION: On a hexahedron-shaped PCa concrete block 20 for an invert part structure, a bolt insertion screwing hole 25 vertically penetrating the hexahedron shape is disposed at corner parts of an isosceles triangle shape and formed at three locations. On the bolt insertion screwing hole 25, a female screw member 25a to which a height adjustment bolt is screwed is fastened to a part lower than an intermediate part in a vertical direction, and a large trumpet-shaped concavity 25b, which opens on an upper surface part 20a so that a diameter thereof is enlarged upward from a part to which the female screw member 25a is fastened, is formed, and a small trumpet-shaped concavity 25c, which opens on a lower surface part 20b so that a diameter thereof is enlarged downward from the part to which the female screw member 25a is fastened, is formed.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to an invert part structure, and particularly to a PCa concrete block for an invert part structure that is provided in the invert part of a mountain tunnel and constitutes an invert part lining body.

Background Art

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

[0003] In addition, since a mountain tunnel is formed by excavating a relatively stable ground, for example, some tunnels constructed decades or more ago omit the lining body of the invert part and only form a lining body in the area from the side wall part of the tunnel to the upper arch-shaped part for secondary lining. For such a mountain tunnel that omits the lining body of the invert part, for example, in the future, it is considered to newly form a lining body of the invert part so as not to be affected by, for example, swelling of the bottom ground.

[0004] As a method of forming the invert lining by connecting it continuously to the lining provided in advance from the side wall portion of the tunnel to the upper arch-shaped portion at the bottom of the tunnel, conventionally, the one using in-situ concrete has been common (for example, see Patent Document 1). However, for the invert lining, a high level of skill is required to finish the upper surface so as to have a curved shape. Furthermore, when in-situ concrete is used, the placed concrete requires a considerable amount of time until a predetermined curing period elapses after hardening. Therefore, especially when newly forming the invert lining from the side wall portion where the invert lining is omitted to the upper arch-shaped portion lining, the passage in the tunnel will be blocked for a long time. Thus, it is desirable to complete the construction in a shorter period of time.

[0005] For this reason, shortening the construction period by forming the invert lining using a precast concrete member manufactured in advance at a factory or the like has also been considered (for example, see Patent Document 2 and Patent Document 3).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, according to the conventional method for constructing the invert part in a mountain tunnel using precast concrete concrete members, these concrete members pre-formed in a factory or the like are formed with a length spanning the entire width in the transverse direction of the invert part, or are formed with a length obtained by dividing the invert part into two to three parts in the transverse direction. Therefore, as the weight and shape become large, it takes a lot of labor to assemble a formwork in a factory or the like and accurately form joint parts and the like. Furthermore, a lot of labor is required for loading and assembling at the construction site. In particular, for example, in a multi-lane road tunnel, when construction is carried out for each lane while maintaining traffic in the other lane, large-sized concrete members that are bulky are used, which involves difficult work.

[0008] In response to the above problems, constructing the invert part using precast concrete blocks (PCa concrete blocks) of appropriate weight and size that are easy to manufacture in a factory or the like is excellent in workability and can be easily formed. Also, as a component of the invert part lining provided continuously with the lining of the upper arch-shaped part from the side wall part of the tunnel, it is preferable in that it can be installed more quickly.

[0009] On the other hand, when constructing the invert part using PCa concrete blocks, it is required to accurately and easily adjust the height of the PCa concrete blocks so that the upper surface (road surface) of the invert part is convex downward and forms a flat curved surface.

[0010] An object of the present invention is to provide a PCa concrete block for an invert part structure that can easily adjust the height and accurately and easily form the invert part so that the upper surface is convex downward and forms a flat curved surface.

Means for Solving the Problems

[0011] The present invention relates to a PCa concrete block used for forming an invert portion structure, which is provided in at least one side region in the transverse direction of a tunnel in the invert portion of a mountain tunnel and constitutes an invert portion covering structure. While maintaining a gap filled with a filling and solidifying material between the receiving base portion at the lower end of the adjacent side wall portion covering structure and between adjacent PCa concrete blocks, it is arranged continuously in the transverse direction of the tunnel. Also, in the axial direction of the tunnel, it is arranged continuously while maintaining a gap filled with a filling and solidifying material between adjacent PCa concrete blocks, and is installed in the invert portion by arranging them side by side vertically and horizontally. It is formed as a hexahedron-shaped block having a curved upper surface portion and a curved lower surface portion along the cross-sectional shape of the invert portion covering structure, and having a pair of flat axial-direction opposing surfaces in the front and rear and a pair of flat transverse-direction opposing surfaces on the left and right. Bolt boxes or female screw anchors for connecting adjacent PCa concrete blocks using bolt members are embedded and fixed at the four-side portions of the upper surface portion of the hexahedron shape. Bolt insertion and screwing holes penetrating the hexahedron shape in the vertical direction are formed at three locations arranged at each corner portion of an isosceles triangle shape. In each bolt insertion and screwing hole, a female screw member for screwing a height adjustment bolt is fixed to a lower portion than the intermediate portion in the vertical direction. A large trumpet-shaped recess is formed that expands in diameter upward from the portion where the female screw member is fixed and opens to the upper surface portion of the PCa concrete block. A small trumpet-shaped recess is formed that expands in diameter downward from the portion where the female screw member is fixed and opens to the lower surface portion of the PCa concrete block. By providing a PCa concrete block for an invert portion structure, the above object is achieved.

[0012] And it is preferable that the three bolt insertion and screwing holes are arranged at each corner portion of the isosceles triangle shape, with the bottom side portion parallel to one of the axial-direction opposing surfaces on the upper surface portion of the PCa concrete block and the top portion arranged on the other axial-direction opposing surface side.

[0013] Further, in the PCa concrete block for the invert portion structure of the present invention, it is preferable that the center of gravity of the PCa concrete block is arranged inside the isosceles triangle shape as viewed from the upper surface side of the PCa concrete block.

[0014] Furthermore, in the PCa concrete block for the invert portion structure of the present invention, it is preferable that the center of gravity of the PCa concrete block is arranged at the centroid position of the isosceles triangle shape as viewed from the upper surface side of the PCa concrete block.

[0015] Moreover, in the PCa concrete block for the invert portion structure of the present invention, it is preferable that a filler injection hole penetrating the hexahedron shape in the vertical direction is formed by being disposed at the central portion of the upper surface portion.

[0016] Also, in the PCa concrete block for the invert portion structure of the present invention, a spacer jig that holds a gap with a predetermined interval width between each of the pair of flat axial direction opposing surfaces and the pair of flat transverse direction opposing surfaces of the hexahedron shape and the other opposing surface facing it is preferably attached.

[0017] Furthermore, in the PCa concrete block for the invert portion structure of the present invention, it is preferable that a plurality of lifting jigs used when lifting each of the PCa concrete blocks are embedded and fixed on the upper surface portion of the hexahedron shape.

Effects of the Invention

[0018] According to the PCa concrete block for the invert portion structure of the present invention, height adjustment can be facilitated so that the upper surface is convex downward and becomes a flush curved surface, and the invert portion can be formed with high precision and easily.

Brief Description of the Drawings

[0019]

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Figure 15

Mode for Carrying Out the Invention

[0020] The invert part structure 10 according to a preferred embodiment of the present invention is, in the mountain tunnel 30 shown in FIG. 1, formed in advance so as to cover the inner wall surface of the tunnel, and is continuous with the lining 31 in the region from the side wall parts 31a on both sides to the upper arch-shaped part 31b. When newly forming an invert part lining 32 on the bottom part 30a of the mountain tunnel 30, as shown in FIGS. 2 and 3, it is constructed one side at a time with the center line C in the transverse direction of the tunnel in between, and is integrated, so that it is provided as a structure that becomes a constituent part of the invert part lining 32.

[0021] In this embodiment, the mountain tunnel 30 is, for example, a tunnel constructed several decades ago, and since the ground to be excavated was stable during construction, the lining 31 covering the inner wall surface of the tunnel was formed only on the side wall parts 31a on both sides and the upper arch-shaped part 31b. However, over time, concerns about the influence of ground swelling, etc. in the bottom part 30a have arisen, so new invert part linings 32 are formed by the invert part structures 10 on both the left and right sides.

[0022] In addition, when newly forming the invert covering structure 32 in the existing mountain tunnel 30, since it is necessary to cut off the passage of the tunnel, it is desirable to complete the construction in as short a construction period as possible. The invert structure 10 of the present embodiment uses a plurality of precast concrete blocks (PCa concrete blocks) that are manufactured in advance at a factory or the like and have an appropriate weight and size that are easy to handle. By doing so, the invert covering structure 32 that is continuous with the lining structure 31 from the side wall portion 31a to the upper arch-shaped portion 31b of the tunnel can be easily formed one side at a time without much effort, and can be installed in a shorter construction period.

[0023] In the present embodiment, as shown in FIGS. 1 to 4, the invert structure 10 is provided in at least one side region in the transverse direction of the tunnel in the invert portion 33 of the mountain tunnel 30, and is a structure of the invert portion 33 using the PCa concrete block 20 that constitutes the invert covering structure 32. As shown in FIGS. 5 and 6(a) to (c), the PCa concrete block 20 is formed as a hexahedron 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 covering structure 32. More specifically, in a cross-sectional view of the PCa concrete block 20, the upper surface portion 20a and the lower surface portion 20b have a downwardly convex curved shape. The upper surface portion 20a and the lower surface portion 20b in the cross-sectional view can be gently curved with a radius of curvature of, for example, about 14000 mm to 14500 mm.

[0024] These multiple PCa concrete blocks 20 are arranged in series in the transverse direction of the tunnel while maintaining gaps 21a and 21b between the lower receiving portions 31c of the adjacent side wall covering members 31a and between the adjacent PCa concrete blocks 20, and are installed in the invert portion 33. Also, in the axial direction of the tunnel, they are arranged in series while maintaining a gap 21b between the adjacent PCa concrete blocks and are installed in the invert portion 33 (see FIGS. 1 to 4). These multiple PCa concrete blocks 20 arranged in series vertically and horizontally are integrated through a filled and solidified material 22 that is filled and cured in the gap 21a between the adjacent receiving portions 31c, the gap 21b between the adjacent PCa concrete blocks 20, and the gap 21c below the hexahedral lower surface portion communicating with these gaps 21a and 21b, and constitute at least a part of the invert portion covering member 32 and one side portion of the invert portion covering member 32.

[0025] Also, in this embodiment, the multiple PCa concrete blocks 20 are preferably formed to have the same hexahedral shape with the transverse width x, the axial length y, and the height z of the tunnel being equal (see FIGS. 5, 6(a) to (c)). The multiple PCa concrete blocks 20 arranged in series vertically and horizontally have a gap 21b extending in the axial direction between the PCa concrete blocks 20 adjacent in the transverse direction of the tunnel filled with the filled and solidified material 22, and a gap 21b extending in the transverse direction between the PCa concrete blocks adjacent in the axial direction of the tunnel, and are preferably arranged in a straight and continuous manner and installed in the invert portion 33 (see FIGS. 2 and 3). The gap 21a between the adjacent receiving portions 31c filled with the filled and solidified material 22 and the gap 21b between the adjacent PCa concrete blocks preferably have a gap width of about 15 to 30 mm.

[0026] In this embodiment, as described above, the plurality of PCa concrete blocks 20 that constitute the invert portion structure 10 are arranged in series in the transverse direction of the tunnel while maintaining the gaps 21a and 21b filled with the filling and solidifying material 22 between the receiving portions 31c at the lower ends of the adjacent side wall covering members 31a and between the adjacent PCa concrete blocks 20. Also, in the axial direction of the tunnel, they are arranged in series while maintaining the gap 21b filled with the filling and solidifying material 22 between the adjacent PCa concrete blocks, and are installed in the invert portion 33 side by side vertically and horizontally. Further, as shown in FIGS. 5 and 6(a) to (c), the PCa concrete block 20 has a curved upper surface portion 20a and a curved lower surface portion 20b having a curved shape along the cross-sectional shape of the invert covering member 32, and is formed as a hexahedron-shaped block having a pair of front and rear flat axial-direction facing surfaces 20c and a pair of left and right flat transverse-direction facing surfaces 20d.

[0027] Furthermore, in each of these PCa concrete blocks 20, a bolt box 23 or a female screw anchor 24 for connecting the adjacent PCa concrete blocks 20 using a bolt member (not shown) is embedded and fixed at the four-side portions in the upper surface portion of the hexahedron shape. The four-side portions are the peripheral edges of the upper surface portion 20a of the PCa concrete block 20 and are constituted by the facing surfaces 20c and 20d that face the adjacent PCa concrete blocks 20 in the axial direction or the transverse direction.

[0028] The bolt box 23 is provided at the upper end portions of one of the transverse-direction facing surfaces 20d and one of the axial-direction facing surfaces 20c in the PCa concrete block 20 and opens to the upper surface portion 20a. The bolt box 23 has an opening (bolt hole) into which a bolt member is inserted in these facing surfaces 20d and 20c, and the opening faces the transverse-direction facing surface 20d or the axial-direction facing surface 20c of another PCa concrete block 20.

[0029] The female screw anchor 24 is provided at the upper ends of the other transverse opposing surface 20d in the transverse direction and the other axial opposing surface 20c in the axial direction in the PCa concrete block 20, and has openings (anchor holes) into which bolt members are inserted in these opposing surfaces 20d, 20c.

[0030] When arranging the PCa concrete block 20 adjacent to another PCa concrete block 20 in the transverse direction or the axial direction with the transverse opposing surfaces 20d facing each other or the axial opposing surfaces 20c facing each other, the positions of the bolt boxes 23 on the opposing surfaces facing each other between the adjacent blocks 20 and the position of the female screw anchor 24 are made to substantially coincide in the transverse direction or the axial direction. In the PCa concrete block 20 of the present embodiment, a bolt box 23 is provided at the center in the width direction (axial direction) of one transverse opposing surface 20d, and a female screw anchor 24 is provided at the center in the width direction (axial direction) of the other transverse opposing surface 20d. Further, bolt boxes 23 are provided at two positions on one axial opposing surface 20c, and female screw anchors 24 are provided at two positions on the other axial opposing surface 20c. On the axial opposing surface 20c, the two bolt boxes 23 or the two female screw anchors 24 are provided at intervals in the transverse direction.

[0031] When viewed in plan from the upper surface portion 20a, of the two transverse opposing surfaces 20d of the central portion side block 20B and the intermediate portion block 20C, the opposing surfaces 20d on which the bolt box 23 is provided are the opposing surfaces 20d on the same side among the plurality of PCa concrete blocks 20B and 20C. On the other hand, the opposing surfaces 20d on which the female screw anchor 24 is provided are the opposing surfaces 20d on the side opposite to the bolt box 23 among the plurality of PCa concrete blocks 20B and 20C. Similarly, of the two axial opposing surfaces 20c, the opposing surfaces 20c on which the bolt box 23 is provided are the opposing surfaces 20c on the same side among the plurality of PCa concrete blocks 20B and 20C. On the other hand, the opposing surfaces 20c on which the female screw anchor 24 is provided are the opposing surfaces 20c on the side opposite to the bolt box 23 among the plurality of PCa concrete blocks 20B and 20C. Thereby, the advancing direction of the connection in the transverse direction or the advancing direction of the connection in the axial direction when connecting the central portion side block 20B or the intermediate portion block 20C becomes a predetermined direction. In the central portion side block 20B and the intermediate portion block 20C in one side region of the present embodiment, the female screw anchor 24 is provided on the transverse opposing surface 20d on the side of the receiving base portion 31c in the transverse direction of the tunnel, and the bolt box 23 is provided on the transverse opposing surface 20d on the central side in the transverse direction.

[0032] The receiving base portion side block 20A has the bolt box 23 and the female screw anchor 24 provided on the axial opposing surface 20c in the same manner as the central portion side block 20B and the intermediate portion block 20C, except that the bolt box 23 is provided on each of the two transverse opposing surfaces 20d.

[0033] Also, as shown in Fig. 7, in the PCa concrete block 20, bolt insertion and screwing holes 25 penetrating the hexahedron shape in the vertical direction are formed at three locations, each disposed at a corner portion of a virtual isosceles triangle shape (see Fig. 6(a)). That is, in a plan view of the block 20 as viewed from the upper surface portion 20a, each of the three bolt insertion and screwing holes 25 is formed so as to be located at the vertex of a virtual isosceles triangle. Thereby, the PCa concrete block 20 can be stably supported by the height adjustment bolts 26 inserted into the bolt insertion and screwing holes 25.

[0034] As shown in Fig. 6(a), the three bolt insertion and screwing holes 25 are preferably arranged in the upper surface portion 20a of the PCa concrete block 20 such that the bottom side is parallel to and disposed on one axial direction facing surface 20c side, and the top is disposed on the other axial direction facing surface 20c side, and are formed at each corner portion of a virtual isosceles triangle shape (see the dashed line) (see Fig. 6(a)). The isosceles triangle formed by the three bolt insertion and screwing holes 25 preferably has an angle between the two equal sides of 80° to 90°. Also, the two bolt insertion and screwing holes 25 located at both ends of the bottom side of the isosceles triangle are formed such that their positions in the transverse direction are substantially the same as that of the bolt box 23 in a plan view (see Fig. 6(a)).

[0035] In the present embodiment, when viewed from the upper surface side of the PCa concrete block 20, it is preferable that the center of gravity of the PCa concrete block 20 is disposed inside the area surrounded by the virtual isosceles triangle shape, and it is particularly preferable that the center of gravity of the PCa concrete block 20 is disposed at the centroid position of the virtual isosceles triangle shape. By these arrangements, it becomes possible to accurately adjust the height and inclination of the PCa concrete block 20 by the three height adjustment bolts 26 in a more stable state, and it also becomes possible to support the PCa concrete block 20 with its height and inclination accurately adjusted by the three height adjustment bolts 26 in a more stable state.

[0036] In each bolt insertion and fastening hole 25, a female screw member 25a to which a height adjustment bolt 26 is screwed is fixed to a portion below the middle part in the vertical direction (see Fig. 7). When the total height of the PCa concrete block 20 is taken as 100%, the position of the lower surface portion 20b of the block 20 in the vertical direction is taken as 0%, and the position of the upper surface portion 20a is taken as 100%, it is preferable that the upper edge of the female screw member 25a is located within the range of 24 to 28% in the vertical direction of the block.

[0037] In addition, a large trumpet-shaped recess 25b that expands in diameter upward and opens to the upper surface portion 20a of the PCa concrete block 20 and a small trumpet-shaped recess 25c that expands in diameter downward and opens to the lower surface portion 20b of the PCa concrete block 20 are formed from the portion where the female screw member 25a of each bolt insertion and fastening hole 25 is fixed. The height adjustment bolt 26 is inserted into these bolt insertion and fastening holes 25 and screwed to the female screw member 25a, so that the height adjustment bolt 26 is attached in a state where the lower end portion 26a protrudes from the lower surface portion 20b of the PCa concrete block 20 so as to be able to advance and retreat. Further, since the large trumpet-shaped recess 25b and the small trumpet-shaped recess 25c have a trumpet shape that expands in a tapered manner toward the upper and lower openings, it is possible to smoothly remove the core removal member attached to the box-shaped formwork for concrete placement after the concrete has hardened in order to form these trumpet-shaped recesses 25b, 25c. From such a viewpoint, it is preferable that the taper gradient of the large trumpet-shaped recess 25b and the small trumpet-shaped recess 25c having a trumpet shape that expands in a tapered manner is inclined by 10% or more with respect to the central axis of the bolt insertion and fastening hole 25.

[0038] In addition, in the present embodiment, some of these PCa concrete blocks 20, i.e., PCa concrete blocks 20' (see FIG. 3), are formed with filler injection holes 27 that penetrate the hexahedral shape in the vertical direction, as shown in FIGS. 10 and 11. In each filler injection hole 27, a female screw member 27a to which the male screw portion of the opening / closing valve 28 is screwed is fixed at an intermediate portion in the vertical direction. From the portion where the female screw member 27a of each filler injection hole 27 is fixed, an upper-side trumpet-shaped recess 27b that expands in diameter upward and opens to the upper surface portion 20a of the PCa concrete block 20' is formed, and from the portion where the female screw member 27a is fixed, a lower-side trumpet-shaped recess 27c that expands in diameter downward and opens to the lower surface portion 20b of the PCa concrete block 20' is formed. In these filler injection holes 27, the male screw portion of the opening / closing valve 28 is screwed to the female screw member 27a, and by arranging the handle portion 28a above the upper surface portion 20a of the PCa concrete block 20', the opening / closing valve 28 is detachably attached to the PCa concrete block 20' in a state where the opening / closing operation of the handle portion 28a can be performed by the operation on the upper surface portion 20a of the PCa concrete block 20'. Further, since the upper-side trumpet-shaped recess 27b and the lower-side trumpet-shaped recess 27c have a trumpet shape that expands in a tapered manner toward the upper and lower openings, the knockout members attached to the box-shaped formwork for concrete placement to form these trumpet-shaped recesses 27b, 27c can be smoothly removed after the concrete has hardened. From this perspective, it is preferable that the taper gradient of these trumpet-shaped recesses 27b, 27c is also inclined by 10% or more with respect to the central axis of the filler injection hole 27.

[0039] Since some of the PCa concrete blocks 20' have the filler injection holes 27, it becomes possible to easily fill the gap 21c between the lower surface portion 20b of each block 20 and the filling bottom surface portion 26c from the upper surface portion 20a of the PCa concrete block 20'. The gap 21c is the gap between the lower surface portion 20b of the PCa concrete block 20 and the filling bottom surface portion 26c that serves as the bottom plate portion (ground).

[0040] In addition, since filling can be performed while fixing the on-off valve 28 to the female screw member 27a of the filler injection hole 27, it is possible to prevent the injection hose for injecting the filled solidifying material 22 from being pushed upward by the filling pressure. The injection hose is connected to the on-off valve 28 and used.

[0041] In each of the upper-side trumpet-shaped recess 27b and the lower-side trumpet-shaped recess 27c in the filler injection hole 27, the height from the opening in the upper surface portion 20a or the lower surface portion 20b of these trumpet-shaped recesses 27b, 27c to the end of the female screw member 27a is preferably about 210 to 230 mm, and the opening diameter of these trumpet-shaped recesses 27b, 27c in the upper surface portion 20a or the lower surface portion 20b is preferably about 118 to 123 mm.

[0042] In the present embodiment, the filler injection hole 27 penetrating the hexahedron-shaped PCa concrete block 20' in the vertical direction can be preferably formed by disposing it at the central portion of the upper surface portion 20a of the PCa concrete block 20' (see Fig. 6(a)). The filler injection hole 27 is particularly preferably formed by disposing it at the central portion of the central block 20B located at the lowest position.

[0043] In addition, in the present embodiment, in each of these PCa concrete blocks 20 (20'), spacer jigs 29a, 29b for holding a gap 21b having a predetermined interval width between the opposing other opposing surfaces 20c, 20d can be attached to each of the pair of flat axial-direction opposing surfaces 20c and the pair of flat transverse-direction opposing surfaces 20d having a hexahedron shape (see Figs. 5, 6(b), and 6(c)). A plurality of lifting jigs 29c used when lifting each PCa concrete block 20 are preferably embedded and fixed to the upper surface portion 20a having a hexahedron shape (see Fig. 6(a)).

[0044] And in this embodiment, these PCa concrete blocks 20 are, for example, in a manufacturing factory, after placing and curing concrete inside a box-shaped formwork assembled into a shape along the above-described predetermined hexahedron shape, and after passing through a predetermined curing period, demolding is performed. Preferably, the upper surface portion 20a and the lower surface portion 20b are formed to have a hexahedron shape that is curved, with a width x of about 1385 to 1435 mm, a length y of about 730 mm, and a height z of about 500 mm, and it will have a weight of about 1300 kg. For example, arranging formwork bars inside the box-shaped formwork and supporting them, and attaching box-out members for the above-described bolt box 23, female screw anchor 24, bolt insertion and screwing holes 25, and filler injection holes 27, etc., enables these to be embedded and fixed or temporarily fixed to the PCa concrete block 20. As described above, the bolt insertion and screwing holes 25 and the filler injection holes 27 have two trumpet-shaped recesses that expand in diameter outward in the vertical direction, so the box-out members of the trumpet-shaped recesses can be easily removed from the mold. In this embodiment, by attaching the box-out members or varying their attachment positions, each of the pedestal-side block 20A, the central-side block 20B, and the intermediate block 20C can be manufactured. In this embodiment, the size, shape, weight, etc. of the PCa concrete block 20 used as an invert block can be appropriately designed according to the capabilities of a crane, etc., so that it can be used in the work yard 71 of one side region 55A without affecting vehicle passage or the like in the other side region 55B. For example, the weight of the PCa concrete block 20 can preferably be 1000 to 1500 kg.

[0045] In addition, in this embodiment, since the plurality of PCa concrete blocks 20 are formed to have the same hexahedral shape, it is possible to limit the types of box-shaped formworks to be used and manufacture them efficiently. Since the blocks have the same weight, the workability during lifting and transportation is improved, and they can be handled in the same way when lifting or installing them. For example, it becomes possible to easily perform the work of accurately installing each PCa concrete block 20 at a predetermined position so as to be arranged in a potato shape. It is also possible to reduce the cost during manufacturing.

[0046] In this embodiment, the invert portion structure 10 is constructed in each of the pair of one-side regions sandwiching the center in the transverse direction of the tunnel (see FIGS. 1 and 2). At the center in the transverse direction of the tunnel in the invert portion 33, in order to prevent the other one-side region from being affected when constructing the invert portion structure 10 in each one-side region, H-shaped steels 35 that support a mountain retaining plate member, a protective fence, etc. can be driven into the ground of the invert portion 33 at predetermined intervals in the axial direction of the tunnel with the flange portions along the axial direction of the tunnel, and a plurality of them can be erected. Therefore, at the central-side end portions of a pair of PCa concrete blocks (central portion-side blocks) 20B adjacent in the axial direction of the tunnel on the central side in the transverse direction of the tunnel at the positions where these H-shaped steels 35 are erected, notch recesses 20e having a rectangular cross-sectional shape can be formed at both corner portions sandwiching the gap 21b therebetween (see FIG. 3). By these notch recesses 20e at both corner portions, a flange arrangement recess 10a for arranging one flange portion of the H-shaped steel 35 can be provided at the portion where the H-shaped steel 35 is erected on the central-side end surface portion (central-side end surface portion) 10B of each invert portion structure 10 on the central side in the transverse direction of the tunnel.

[0047] That is, in the block groups 20X and 20Y (see FIG. 1) composed of a plurality of PCa concrete blocks 20 that constitute the invert part structure 10 of each one-sided region, the PCa concrete block 20 (central part side block 20B) disposed at the portion where the H-shaped steel 35 stands upright is formed as a hexahedral block having a curved upper surface portion 20a and a lower surface portion 20b with a curved shape along the cross-sectional shape of the invert part covering member 32, and having a pair of flat axial direction opposing surfaces 20c in the front and rear and a pair of flat transverse direction opposing surfaces 20d in the left and right (see FIGS. 6(a) to (c)). As shown in FIG. 3, at the corner portion of any one of the axial direction opposing surface 20c and the transverse direction opposing surface 20d, a notch recess 20e having a rectangular cross-sectional shape and being notched so as to have a side portion with a width of at least 1 / 2 of the lateral width of the flange portion of the H-shaped steel 35 is continuously provided from the upper surface portion 20a to the lower surface portion 20b. As a result, at the central side end portions of the pair of central part side blocks 20B adjacent in the axial direction of the tunnel at the portion where the H-shaped steel 35 stands upright, flange arrangement recesses 10a capable of bypassing the flange portions of the H-shaped steel 35 are formed by these notch recesses 20e.

[0048] And in the present embodiment, these plurality of PCa concrete blocks 20 that constitute the invert portion structure 10 are, as shown in FIGS. 3 and 4, a pedestal side block 20A arranged adjacent to the pedestal portion 31c at the lower end of the side wall covering member 31a, a central portion side block 20B arranged on the central portion side in the transverse direction of the invert portion, and one or a plurality of intermediate blocks 20C (in this embodiment, one intermediate block 20C) arranged therebetween, and have a plurality of transverse direction block rows 20D. These PCa concrete blocks 20A, 20B, 20C are arranged continuously in the transverse direction of the tunnel while maintaining gaps 21a, 21b between adjacent pedestal portions 31c and between adjacent PCa concrete blocks 20A, 20B, 20C, and are also arranged continuously in the axial direction of the tunnel while maintaining a gap 21b between adjacent PCa concrete blocks 20A, 20B, 20C (transverse direction block rows 20D), and are installed in the invert portion 33 by arranging them side by side vertically and horizontally. These plurality of PCa concrete blocks 20A, 20B, 20C used when constructing the invert portion structure 10 can be constructed by the following method for installing PCa blocks in the invert portion.

[0049] That is, in the method for installing PCa blocks in the invert portion according to the present embodiment, for the plurality of PCa concrete blocks 20A, 20B, 20C of each transverse direction block row 20D arranged continuously in the transverse direction of the tunnel, as shown in FIG. 4, after installing the pedestal side block 20A adjacent to the pedestal portion 31c and temporarily fixing it with the temporary fixing means 36, the intermediate block 20C and the central portion side block 20B are sequentially installed adjacent to the temporarily fixed pedestal side block 20A, so that the plurality of PCa concrete blocks 20A, 20B, 20C of each row (transverse direction block row) 20D arranged continuously in the transverse direction of the tunnel are installed in the invert portion 33.

[0050] For example, after installing the pedestal-side block 20A adjacent to the pedestal 31c and temporarily fixing it with the temporary fixing means 36, the intermediate block 20C and the central-side block 20B are sequentially installed adjacent to the temporarily fixed pedestal-side block 20A. At each adjacent location of these installed blocks 20A, 20B, 20C, through the bolt box 23 disposed on the upper surface portion 20a of at least one of the PCa concrete blocks 20A, 20B, 20C close to the transverse opposing surface 20d, after temporarily fixing with a bolt member (not shown), the height and position of each of the PCa concrete blocks 20A, 20B, 20C are adjusted, and then the bolt member is tightened. By doing so, a plurality of PCa concrete blocks 20A, 20B, 20C of each transverse block row 20D continuously arranged in the transverse direction of the tunnel can be installed on the invert portion 33.

[0051] Also, for example, after installing the pedestal-side block 20A adjacent to the pedestal 31c and temporarily fixing it with the temporary fixing means 36, the intermediate block 20C is installed adjacent to the temporarily fixed pedestal-side block 20A. At the adjacent location of the installed intermediate block 20C and the pedestal-side block 20A, through the bolt box 23 disposed on the upper surface portion 20a of at least one of the PCa concrete blocks 20A, 20C close to the transverse opposing surface 20d, it is temporarily fixed with a bolt member (not shown). Then, after adjusting the height and position of each of the PCa concrete blocks 20A, 20C, the bolt member is tightened. Subsequently, the central-side block 20B is installed adjacent to the intermediate block 20C. At the adjacent location of the installed central-side block 20B and the intermediate block 20C, through the bolt box 23 disposed on the upper surface portion 20a of at least one of the PCa concrete blocks 20C, 20B close to the transverse opposing surface 20d, after temporarily fixing with a bolt member, after adjusting the height and position of the central-side block 20B, by tightening the bolt member, a plurality of PCa concrete blocks 20A, 20B, 20C of each transverse block row 20D continuously arranged in the transverse direction of the tunnel can also be installed on the invert portion 33.

[0052] Here, in the present embodiment, the temporary fixing means 36 for temporarily fixing the pedestal-side block 20A adjacent to the pedestal 31c can preferably be constituted by a cord body 36b such as a wire or a chain, with both ends locked to a locking member attached to a hole-in anchor 36a embedded in the pedestal 31c and a locking member attached to a bolt box 23 or a suspension jig 29c provided on the pedestal-side block 20A. The cord body 36b such as a wire or a chain can be provided with a stretching adjustment means 36c such as a turnbuckle or the like that can adjust the length between both ends to be locked. Thereby, the interval width of the gap 21a held between the pedestal 31c and the adjacent pedestal-side block 20A can be made adjustable.

[0053] Also, in the present embodiment, the height adjustment of each of the PCa concrete blocks 20A, 20B, and 20C can be carried out using three height adjustment bolts 26 screwed into the bolt insertion and screwing holes 25 formed at the above-described three locations, as shown in FIGS. 6(a) and 7. That is, in each of the PCa concrete blocks 20A, 20B, and 20C, the bolt insertion and screwing holes 25 are formed at three locations penetrating in the vertical direction, and in each of the bolt insertion and screwing holes 25, the height adjustment bolts 26 are attached in a state where the lower end portions 26a can protrude downward from the lower surface portions 20b of the PCa concrete blocks 20A, 20B, and 20C. Prior to the step of filling the gaps 21a between the adjacent receiving base portions 31c of the plurality of PCa concrete blocks 20A, 20B, and 20C arranged continuously in the vertical and horizontal directions, the gap 21b between the adjacent PCa concrete blocks 20A, 20B, and 20C, and the gap 21c below the hexahedral lower surface portion 20b communicating with these gaps 21a and 21b with the filling and solidifying material 22 (see FIG. 10), by a rotation operation from above the PCa concrete blocks 20A, 20B, and 20C, the protruding lengths of the three height adjustment bolts 26 from the lower surface portions 20b of the PCa concrete blocks 20A, 20B, and 20C in each of the PCa concrete blocks 20A, 20B, and 20C are changed, and a step of adjusting the height and inclination of each of the PCa concrete blocks 20A, 20B, and 20C is performed.

[0054] As described above, in the present embodiment, a nut member is preferably fixed as a female screw member 25a to a portion below the middle portion in the vertical direction of each bolt insertion and screwing hole 25. By screwing the height adjustment bolt 26 to the nut member 25a, the height adjustment bolt 26 is attached in a state where the lower end portion 26a can protrude downward from the lower surface portion 20b of the PCa concrete blocks 20A, 20B, and 20C. Further, a tiltable ground contact adjuster 26b can be attached to the lower end portion 26a of the height adjustment bolt 26 (see Fig. 8(a)). By tilting the ground contact adjuster 26b with respect to the lower end portion 26a of the height adjustment bolt 26, the adjuster 26b can be tilted along, for example, the ground surface serving as the filling bottom surface portion 26c. As a result, the lower end portion 26a of the height adjustment bolt 26 can be grounded to the filling bottom surface portion 26c below the lower surface portion 20b in a stable state.

[0055] When the height adjustment bolt 26 is retracted upward, the ground adjusting member 26b is preferably configured to be accommodated in the above-described small trumpet-shaped concave portion 25c that expands in diameter downward. For example, as shown in FIG. 8(b), by forming the small trumpet-shaped concave portion 25c into a trumpet-shaped concave portion that expands in diameter downward and is slightly larger than the outer peripheral shape of the ground adjusting member 26b, the ground adjusting member 26b having the same shape as the small trumpet-shaped concave portion 25c can be easily accommodated inside the small trumpet-shaped concave portion 25c without protruding downward from the lower surface portion 20b of the PCa concrete block 20. As a result, even when the gap 21c between the lower surface portion 20b of the PCa concrete block 20 and the filling bottom surface portion 26c is less than the height of the ground adjusting member 26b, the adjusting member 26b can be grounded to the filling bottom surface portion 26c, enabling fine adjustment of the height of the PCa concrete block 20. Further, even when the height position of the filling bottom surface portion 26c after leveling is the same as the design position of the lower surface portion 20b of the PCa concrete block 20 and there is no margin, the entire ground adjusting member 26b can be accommodated in the small trumpet-shaped concave portion 25c, and each PCa concrete block 20 can be installed at a predetermined position with these lower surface portions 20b being in contact with the filling bottom surface portion 26c.

[0056] Preferably, the height from the opening in the lower surface portion 20b of the PCa concrete block 20 to the lower end of the female screw member 25a in the small trumpet-shaped concave portion 25c is about 60 to 80 mm, and the opening diameter in the lower surface portion 20b is about 65 to 70 mm. From the viewpoint of facilitating removal of the knockout member after the concrete has hardened, the taper gradient of the small trumpet-shaped concave portion 25c is preferably inclined by 10% or more with respect to the central axis of the bolt insertion and screwing hole 25.

[0057] In addition, in the present embodiment, the upper end portion 26d of the height adjustment bolt 26 is preferably formed to have a rectangular cross section. For example, an insert extension bar is locked to the upper end portion 26d as a rotation operation jig, and by rotating the height adjustment bolt 26, the protruding length of the lower end portion 26a of the height adjustment bolt 26 from the lower surface portion 20b of the PCa concrete blocks 20A, 20B, and 20C can be easily changed by working above the upper surface portion 20a of the PCa concrete blocks 20A, 20B, and 20C. As described above, the bolt insertion and screwing 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 portion 20a of the PCa concrete blocks 20A, 20B, and 20C. When the upper end portion 26d of the height adjustment bolt 26 protrudes from the upper surface portion 20a of the PCa concrete blocks 20A, 20B, and 20C or is close to the upper surface portion 20a, and when a sufficient covering thickness cannot be ensured above the upper end portion 26d when the large trumpet-shaped recess 25b is filled with a finishing filler, the upper end portion 26d of the height adjustment bolt 26 can be appropriately cut to a required length in the large trumpet-shaped recess 25b. Thereby, it becomes possible to ensure a desired covering thickness with a finishing filler such as mortar filled in the bolt insertion and screwing hole 25 and prevent the height adjustment bolt 26 from corroding. The operation of cutting the upper end portion 26d of the height adjustment bolt 26 can be performed smoothly because a sufficient working space can be ensured in the large trumpet-shaped recess 25b that expands upward.

[0058] It is preferable that the large trumpet-shaped recess 25b has a height of about 360 to 380 mm from the opening in the upper surface portion 20a of the PCa concrete block 20 to the upper end of the female screw member 25a and an opening diameter in the upper surface portion 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 and screwing hole 25 from the viewpoint of facilitating removal of the knockout member after the concrete has hardened.

[0059] And in this embodiment, as described above, in each of the PCa concrete blocks 20A, 20B, and 20C, bolt insertion and screwing holes 25 are formed at three locations penetrating in the vertical direction. A height adjustment bolt 26 is attached to each bolt insertion and screwing hole 25 in a state where the protruding length of the lower end portion 26a protruding downward from the lower surface portion 20b of the PCa concrete blocks 20A, 20B, and 20C can be adjusted. As a result, the gap 21a between the adjacent receiving base portions 31c of the plurality of PCa concrete blocks 20A, 20B, and 20C arranged continuously in the vertical and horizontal directions, the gap 21b between the adjacent PCa concrete blocks 20A, 20B, and 20C, and the gap 21c below the hexahedral lower surface portion 20b communicating with these gaps 21a and 21b. Prior to the step of filling the filling and solidifying material 22, the interval width b (see FIGS. 7 and 10) of the gap 21c below the hexahedral lower surface portion 20b is measured from the protruding length of the lower end portion 26a of the height adjustment bolt 26 protruding from the lower surface portion 20b of each of the PCa concrete blocks 20A, 20B, and 20C. Based on this and the area of the lower surface portion 20b of the PCa concrete blocks 20A, 20B, and 20C, the estimated filling amount of the filling and solidifying material 22 to be filled in the gap 21c below the hexahedral lower surface portion 20b can be calculated in advance. In the step of filling the filling and solidifying material 22, a predetermined amount of the filling and solidifying material 22 is injected into the gap 21c below the hexahedral lower surface portion 20b and filled and hardened in consideration of the calculated estimated filling amount.

[0060] That is, in the present embodiment, a nut member 25a is fixed as a female screw member to a portion below the middle in the vertical direction of each bolt insertion and screwing hole 25. By screwing a height adjustment bolt 26 to the nut member 25a, the height adjustment bolt 26 is attached in a state where the protruding length of the lower end portion 26a from the lower surface portion 20b of the PCa concrete blocks 20A, 20B, and 20C can be adjusted. For example, when the lower end portion 26a of the height adjustment bolt 26 is grounded to the filling bottom surface portion 26c below the hexahedral lower surface portion 20b, the interval 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 in the portion above the nut member 25a.

[0061] Also, in the present embodiment, preferably, a tiltable grounding adjuster 26b is attached to the lower end portion 26a of the height adjustment bolt 26. When the grounding adjuster 26b is grounded to the filling bottom surface portion 26c below the hexahedral lower surface portion 20b, the interval 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 in the portion above the nut member 25a.

[0062] The planned filling amount of the filling and solidifying material 22 can be calculated in advance by calculating the filling amount to be filled in the gap 21c below the hexahedral lower surface portion 20b of each of the PCa concrete blocks 20A, 20B, and 20C based on the average of the interval widths b of the gaps 21c below the hexahedral lower surface portion 20b measured by the three height adjustment bolts 26 attached to the three bolt insertion and screwing holes 25 of each of the PCa concrete blocks 20A, 20B, and 20C.

[0063] Further, the planned filling amount of the filling and solidifying material 22 can also be calculated in advance by calculating the filling amount filled in the gaps below the hexahedral lower surface portions 20b of the PCa concrete blocks 20A, 20B, and 20C that make up the invert portion structure 10, based on the overall average of the interval width b of the gaps 21c below the hexahedral lower surface portions 20b, which are respectively measured by three height adjustment bolts 26 attached to three bolt insertion and screwing holes 25 in each of the PCa concrete blocks 20A, 20B, and 20C that make up the invert portion structure 10.

[0064] Furthermore, in the present embodiment, in the invert portion structure 10 using the above-described PCa concrete blocks 20A, 20B, and 20C, as a structure of a connecting portion for connecting and arranging the plurality of PCa concrete blocks 20A, 20B, and 20C vertically and horizontally in a state where a gap 21b with a predetermined interval width is maintained between adjacent PCa concrete blocks 20A, 20B, and 20C and installing them integrally in the invert portion 33, the following connecting portion structure 37 of the PCa concrete block in the invert portion structure can be adopted.

[0065] That is, in the present embodiment, as shown in FIGS. 3, 4, and 6(a) to (c), the connecting portion structure 37 of the PCa concrete blocks in the inverter portion structure is provided with a transverse direction spacer jig 29a (see FIG. 6(b)) fixed to one of the pair of transverse direction opposing surfaces 20d facing each other in the transverse direction of the PCa concrete blocks 20A, 20B, and 20C adjacent in the transverse direction of the tunnel, preferably arranged and interposed at least at three locations. Further, in the bolt box 23 disposed on the upper surface portion 20a of at least one of the PCa concrete blocks 20A, 20B, and 20C close to these transverse direction opposing surfaces 20d, a bolt member (not shown) is fastened, and by the fastening force of the bolt member, each pair of PCa concrete blocks 20A, 20B, and 20C adjacent in the transverse direction of the tunnel are connected while maintaining a gap 21b with a predetermined interval width between the transverse direction opposing surfaces 20d. Also, between each pair of axial direction opposing surfaces 20c facing each other in the axial direction of the PCa concrete blocks 20A, 20B, and 20C adjacent in the axial direction of the tunnel, an axial direction spacer jig 29b (see FIG. 6(c)) fixed to one of the pair of axial direction opposing surfaces 20c is preferably arranged and interposed at least at three locations. Further, in the bolt box 23 disposed on the upper surface portion 20a of at least one of the PCa concrete blocks 20A, 20B, and 20C close to these axial direction opposing surfaces 20c, a bolt member (not shown) is fastened, and by the fastening force of the bolt member, each pair of PCa concrete blocks 20A, 20B, and 20C adjacent in the axial direction of the tunnel are connected while maintaining a gap 21b with a predetermined interval width between the axial direction opposing surfaces 20c. The transverse direction spacer jig 29a and the axial direction spacer jig 29b can also be attached to the transverse direction opposing surfaces 20d and the axial direction opposing surfaces 20c at the positions where the bolt box 23 is provided.

[0066] In this embodiment, the transverse direction spacer jig 29a and / or the axial direction spacer jig 29b can preferably be made of a mortar block that is attached and fixed to one of the opposing surfaces 20c and 20d. The spacer jigs 29a and 29b made of mortar blocks can be detachably attached from the opposing surfaces 20c and 20d, and can also be removed after the PCa concrete blocks 20A, 20B, and 20C are tightly fastened and connected. The transverse direction spacer jig 29a and / or the axial direction spacer jig 29b can preferably be made of a male screw member that is fixed in an adjustable protruding length by being screwed into a female screw insert embedded in one of the opposing surfaces 10c and 10d.

[0067] The transverse direction spacer jig 29a or the axial direction spacer jig 29b, which is fixed to one of the transverse direction opposing surfaces 20d or the axial direction opposing surface 20c and is preferably arranged at at least three positions, is preferably fixed at at least two positions in a region below the center of gravity position of the PCa concrete blocks 20A, 20B, and 20C. As a result, when installing the PCa concrete blocks 20A, 20B, and 20C, it is possible to accurately and appropriately form the gaps 21a and 21b at a predetermined interval in a stable state in a region below the center of gravity position where it is difficult to confirm that the gaps 21a and 21b are accurately provided without using a special device.

[0068] In the bolt box 23 disposed on the upper surface portion 20a of at least one of the PCa concrete blocks 20A, 20B, 20C close to the transverse direction facing surface 20d, the bolt member fastened in the bolt box 23, and in the bolt box 23 disposed on the upper surface portion 20a of at least one of the PCa concrete blocks 20A, 20B, 20C close to the axial direction facing surface 20c, the bolt member fastened in the bolt box 23 may preferably be fastened across the bolt box 23 disposed on the upper surface portion 20a close to the axial direction facing surface 20c or the transverse direction facing surface 20d of one of the PCa concrete blocks 20A, 20B, 20C and the female screw anchor 24 embedded in the axial direction facing surface 20c or the transverse direction facing surface 20d of the other PCa concrete block 20A, 20B, 20C. Preferably, it may be fastened across the bolt box 23 disposed on the upper surface portion 20a close to the axial direction facing surface 20c or the transverse direction facing surface 20d of one of the PCa concrete blocks 20A, 20B, 20C and the bolt box 23 disposed on the upper surface portion 20a close to the axial direction facing surface 20c or the transverse direction facing surface 20d of the other PCa concrete block 20A, 20B, 20C.

[0069] And in this embodiment, when the mountain tunnel includes a portion having a tunnel alignment that curves in the horizontal direction, the plurality of PCa concrete blocks 20A, 20B, 20C are arranged longitudinally and transversely in a state where a gap 21b having a predetermined interval width is held between the adjacent PCa concrete blocks 20A, 20B, 20C and along the tunnel alignment that curves in the horizontal direction, and can be integrally installed in the invert portion 33.

[0070] That is, in the present embodiment, between each pair of transverse direction facing surfaces 20d of the PCa concrete blocks 20A, 20B, 20C adjacent in the transverse direction of the tunnel and facing each other in the transverse direction, a transverse direction spacer jig 29a (see Fig. 6(b)) fixed to one of the transverse direction facing surfaces 20d is disposed and interposed at at least three locations. And by the tightening force of a bolt member (not shown), each pair of PCa concrete blocks 20A, 20B, 20C adjacent in the transverse direction of the tunnel are connected in a state of holding a gap 21b with a predetermined gap width between the transverse direction facing surfaces 20d, forming a transverse direction block row 20D by a plurality of PCa concrete blocks 20A, 20B, 20C (see Fig. 3). Between each pair of axial direction facing surfaces 20c of the PCa concrete blocks 20A, 20B, 20C adjacent in the axial direction of the tunnel and facing each other in the axial direction, an axial direction spacer jig 29b (see Fig. 6(c)) fixed to one of the axial direction facing surfaces 20c is disposed and interposed at at least three locations. And by the tightening force of a bolt member (not shown), each pair of PCa concrete blocks 20A, 20B, 20C adjacent in the axial direction of the tunnel are connected in a state of holding a gap 21b with a predetermined gap width between the axial direction facing surfaces 20c (see Fig. 3). And as shown in Fig. 9(a), in one or two or more connecting portions 20f in the axial direction of the tunnel between the transverse direction block rows 20D arranged in series in the axial direction of the tunnel, the axial direction spacer jig 29b interposed between a pair of axial direction facing surfaces 20c in the axial direction of the tunnel is fixed to the outer PCa concrete block 20E located outside the tunnel linear shape that curves in the horizontal direction in the transverse direction of the tunnel. The width of the outer gap 21b held by the axial direction spacer jig 29b is larger than the width of the inner gap 21b held by the axial direction spacer jig 29b and fixed to the inner PCa concrete block 20F located inside the tunnel linear shape that curves in the horizontal direction. The intervening width is adjusted and fixed to the axial direction facing surface 20c. As a result, it becomes possible to integrally install a plurality of PCa concrete blocks 20A, 20B, 20C in a state of being arranged longitudinally and transversely along the tunnel linear shape that curves in the horizontal direction and install them integrally in the invert portion 33.Accordingly, even without using tapered blocks, it becomes possible to use rectangular parallelepiped-shaped PCa concrete blocks 20A, 20B, and 20C to correspond to a tunnel alignment that curves horizontally.

[0071] Here, when the axial spacer jig 29b is made of a mortar block attached and fixed to one of the axial opposing surfaces 20c, in the connecting portion 20f with different intervening widths, by fixing mortar blocks of different sizes to the outer PCa concrete block 20E and the inner PCa concrete block 20F, the intervening width can be adjusted so that the interval width of the outer gap 21b becomes larger than the interval width of the inner gap 21b.

[0072] Also, when the axial spacer jig 29b is made of a male screw member that is fixed in a manner that allows adjustment of the protruding length by being screwed into a female screw insert embedded in one of the axial opposing surfaces 20c, in the connecting portion 20f with different intervening widths, by screwing and fixing the male screw member with different screwing amounts to the outer PCa concrete block 20E and the inner PCa concrete block 20F, the intervening width can be adjusted so that the interval width of the outer gap 21b becomes larger than the interval width of the inner gap 21b.

[0073] On the other hand, in this embodiment, when the mountain tunnel includes a portion having a tunnel alignment that curves in the vertical direction, a plurality of PCa concrete blocks 20A, 20B, and 20C are arranged vertically and horizontally in a state where a gap 21b with a predetermined interval width is maintained between adjacent PCa concrete blocks 20A, 20B, and 20C and along the tunnel alignment that curves in the vertical direction, and can be installed integrally with the invert portion 33.

[0074] That is, in the present embodiment, between each pair of transverse direction facing surfaces 20d of the PCa concrete blocks 20A, 20B, 20C adjacent in the transverse direction of the tunnel and facing each other in the transverse direction, a transverse direction spacer jig 29a (see Fig. 6(b)) fixed to one of the transverse direction facing surfaces 20d is disposed and interposed at at least three locations. And by the tightening force of a bolt member (not shown), each pair of PCa concrete blocks 20A, 20B, 20C adjacent in the transverse direction of the tunnel are connected in a state of holding a gap 21b with a predetermined interval width between the transverse direction facing surfaces 20d, forming a transverse direction block row 20D by a plurality of PCa concrete blocks 20A, 20B, 20C (see Fig. 3). Between each pair of axial direction facing surfaces 20c of the PCa concrete blocks 20A, 20B, 20C adjacent in the axial direction of the tunnel and facing each other in the axial direction, an axial direction spacer jig 29b (see Fig. 6(c)) fixed to one of the axial direction facing surfaces 20c is disposed and interposed at at least three locations. And by the tightening force of a bolt member (not shown), each pair of PCa concrete blocks 20A, 20B, 20C adjacent in the axial direction of the tunnel are connected in a state of holding a gap 21b with a predetermined interval width between the axial direction facing surfaces 20c. And as shown in Fig. 9(b), in one or two or more axial direction connection portions 20g of the tunnel in the axial direction between the transverse direction block rows 20D arranged in series in the axial direction of the tunnel, at least three axial direction spacer jigs 29b interposed between each pair of axial direction facing surfaces 20c facing each other in the axial direction of the tunnel are fixed to the axial direction facing surfaces 20c in a state where the intervening width is adjusted so that the interval width of the upper gap 21b held by the axial direction spacer jig 29b disposed in the upper stage and the interval width of the lower gap 21b held by the axial direction spacer jig 29b disposed in the lower stage are different widths. Thereby, it becomes possible to vertically and horizontally connect and arrange a plurality of PCa concrete blocks 20A, 20B, 20C along a tunnel linear shape that curves in the vertical direction and install them integrally in the invert portion 33.Also, by this method, even without using tapered blocks, it becomes possible to use rectangular parallelepiped-shaped PCa concrete blocks 20A, 20B, and 20C to correspond to a tunnel linear shape that curves in the vertical direction.

[0075] For example, in the connecting portion 20g with different intervening widths, by adjusting these intervening widths so that the interval width of the upper gap 21b held by the axial spacer jig 29b arranged in the upper stage is larger than the interval width of the lower gap 21b held by the axial spacer jig 29b arranged in the lower stage, it becomes possible to arrange a plurality of horizontally connected block rows 20D along a tunnel linear shape that curves downward in the vertical direction.

[0076] Also, in the connecting portion 20g with different intervening widths, by adjusting these intervening widths so that the interval width of the upper gap 21b held by the axial spacer jig 29b arranged in the upper stage is smaller than the interval width of the lower gap 21b held by the axial spacer jig 29b arranged in the lower stage, it becomes possible to arrange a plurality of horizontally connected block rows 20D along a tunnel linear shape that curves upward in the vertical direction.

[0077] Here, when the axial spacer jig 29b is made of a mortar block attached and fixed to any one of the axial opposing surfaces 20c, in the connecting portion 20g with different intervening widths, by fixing mortar blocks of different sizes in the upper and lower stages, the intervening width can be adjusted so that the interval width of the gap 21b held in the upper part and the interval width of the gap 21b held in the lower part are different widths.

[0078] Also, when the axial spacer jig 29b is screwed into a female screw insert embedded in one of the axially facing surfaces 20c and is fixed in an adjustable protruding length by a male screw member, in the connecting portion 20g with different intervening widths, the male screw member is screwed and fixed with different screwing amounts in the upper and lower stages, so that the intervening width can be adjusted so that the interval width of the gap 21b held in the upper part and the interval width of the gap 21b held in the lower part are different widths.

[0079] And in this embodiment, the plurality of PCa concrete blocks 20A, 20B, 20C arranged longitudinally and transversely in series are, as shown in FIG. 10, the gap 21a between adjacent receiving base portions 31c, the gap 21b between adjacent PCa concrete blocks 20A, 20B, 20C, and the gap 21c below the hexahedral lower surface portion communicating with these gaps are filled and cured, and are integrated via the filling and solidifying material 22 so as to constitute at least a part of the invert portion covering work body 32. In this embodiment, by the following construction method, the gap 21a between adjacent receiving base portions 31c, the gap 21b between adjacent PCa concrete blocks 20A, 20B, 20C, and the gap 21c below the hexahedral lower surface portion communicating with these gaps 21a, 21b are filled with the filling and solidifying material 22.

[0080] That is, in the present embodiment, in the step of filling the gap 21a between adjacent receiving base portions 31c of a plurality of PCa concrete blocks 20A, 20B, 20C arranged longitudinally and transversely, the gap 21b between adjacent PCa concrete blocks 20A, 20B, 20C, and the gap 21c below the hexahedral lower surface portion communicating with these gaps 21a, 21b with the filling and solidifying material 22, the opening portions of the gaps 21a, 21b opening in the upper surface portion 20a, the wife-side end surface portion 10A (see FIGS. 3 and 12), and the central-side end surface portion 10B (see FIGS. 3 and 12) of the plurality of PCa concrete blocks 20A, 20B, 20C arranged longitudinally and transversely are closed. Thereafter, as shown in FIGS. 10 to 12, from the central portion-side filling material injection holes 27d provided penetrating in the vertical direction in one or two or more of the plurality of central portion-side blocks 20B arranged in the axial direction of the tunnel, and from the receiving base portion-side filling material injection holes 27e provided penetrating in the vertical direction in one or two or more of the plurality of receiving base portion-side blocks 20A arranged in the axial direction of the tunnel, the filling and solidifying material 22 is sequentially injected. Preferably, as shown in FIG. 12, after starting the injection of the filling and solidifying material 22 from the central portion-side filling material injection holes 27d, switching to the filling material injection holes 27e on the receiving base portion 31c side and further injecting the filling and solidifying material 22, it is confirmed that the filling and solidifying material 22 flows out from the opening portion of the gap 21a between the receiving base portion 31c held on the upper surface portion 20a of the receiving base portion-side block 20A, and the filling of the filling and solidifying material 22 is terminated. It is also possible to inject the filling and solidifying material 22 using only the filling material injection holes 27d of the central portion-side blocks 20B without using the filling material injection holes 27e of the receiving base portion-side blocks 20A, and confirm that the filling and solidifying material 22 flows out from the opening portion of the gap 21a between the receiving base portion 31c held on the upper surface portion 20a of the receiving base portion-side block 20A, and terminate the filling of the filling and solidifying material 22.

[0081] In addition, in the present embodiment, the plurality of PCa concrete blocks 20A, 20B, 20C arranged longitudinally and transversely are preferably provided adjacent to each other in the axial direction of the tunnel of the existing invert structure 40 (see FIGS. 3 and 12) formed previously. With the opening portion of the gap 21d between the existing invert structure 40 and the upper surface portions 20a and the central side end surface portions 10B of the plurality of PCa concrete blocks 20A, 20B, 20C arranged longitudinally and transversely closed, preferably as shown in FIG. 12, while switching from the central portion side filling material injection hole 27d located on the existing invert structure 40 side to the central portion side filling material injection hole 27d located on the wife side, the filling and solidifying material 22 is injected, and while switching from the filling material injection hole 27e on the pedestal side located on the existing invert structure 50 side to the filling material injection hole 27e on the pedestal side located on the wife side, the filling and solidifying material 22 is injected. After switching from the filling material injection hole 27d of the central portion side block 20B on the existing invert structure 50 side to the filling material injection hole 27d of the central portion side block 20B on the wife side and injecting the filling and solidifying material 22 halfway, it is also possible to further switch from the filling material injection hole 27e of the pedestal side block 20A on the existing invert structure 50 side to the filling material injection hole 27e of the pedestal side block 20A on the wife side and inject the filling and solidifying material 22.

[0082] Furthermore, in this embodiment, preferably, the upper surface strip-shaped formwork 41a is overlapped and fixedly attached to the upper surface portion 20a so as to cover the opening portions of the gaps 21b in the upper surface portions 20a of the plurality of PCa concrete blocks 20A, 20B, 20C arranged in series vertically and horizontally, whereby the opening portions of the upper surface portion 20a are closed (see FIGS. 10 and 13). Also in the wife-side end surface portion 10A, preferably, the wife-side strip-shaped formwork 41b is overlapped and fixedly attached to the wife-side end surface portion 10A so as to cover the opening portions of the gaps 21a, 21b, 21c, whereby the opening portions of the wife-side end surface portion 10A are closed (see FIG. 14). Also in the central-side end surface portion 10B, similarly to the wife-side end surface portion 10A, preferably, the central-side strip-shaped formwork 41c is overlapped and fixedly attached to the central-side end surface portion 10B so as to cover the opening portions of the gaps 21b, 21c, 21d, whereby the opening portions of the central-side end surface portion 10B are closed (see FIG. 10).

[0083] Also, the upper surface strip-shaped formwork 41a, the wife-side strip-shaped formwork 41b, and the central-side strip-shaped formwork 41c are preferably formed using a transparent plate-like member. Thereby, it becomes possible to visually recognize the filling state of the filling and solidifying material 22 into the respective gaps 21a, 21b, 21c, 21d through these transparent strip-shaped formworks.

[0084] Furthermore, the upper surface strip-shaped formwork 41a, which is attached so as to cover the opening portions of the gaps 21a, 21b, 21d in the upper surface portion 20a of the plurality of PCa concrete blocks 20A, 20B, 20C arranged in series vertically and horizontally, is preferably provided with an air vent hose 42 (see FIG. 10) extending from an appropriate position and communicating with the gaps 21a, 21b, 21d in the upper surface portion 20a. Thereby, when the filling and solidifying material 22 is filled, it becomes possible to effectively vent air from the gaps 21a, 21b, 21d through the air vent hose 42, and it also becomes possible to confirm that the filling and solidifying material 22 has been filled by the outflow of the filling and solidifying material 22 from these air vent hoses 42.

[0085] In this embodiment, in the step of filling the gap 21a between adjacent receiving base portions 31c of a plurality of PCa concrete blocks 20A, 20B, 20C arranged longitudinally and transversely, the gap 21b between adjacent PCa concrete blocks 20A, 20B, 20C, and the gap 21c below the hexahedral lower surface portion communicating with these gaps 21a, 21b with the filling and solidifying material 22, as described above, with the opening portions of the gaps 21a, 21b, 21c that open in the upper surface portion 20a of the plurality of PCa concrete blocks 20A, 20B, 20C arranged longitudinally and transversely, the wife-side end surface portion 10A, and the center-side end surface portion 10B closed, the filling and solidifying material 22 is sequentially injected from the center-side filling material injection holes 27d provided to penetrate vertically through one or more of the plurality of center-side blocks 20B arranged longitudinally in the tunnel axis direction, and from the receiving base-side filling material injection holes 27e provided to penetrate vertically through one or more of the plurality of receiving base-side blocks 20A arranged longitudinally in the tunnel axis direction. Opening and closing valves 28 that can be opened and closed are respectively attached to the center-side filling material injection holes 27d and the receiving base-side filling material injection holes 27e. When sequentially connecting an injection hose to the opening and closing valve 28 of the selected center-side filling material injection hole 27d or the receiving base-side filling material injection hole 27e to fill the filling and solidifying material 22, the opening and closing valve 28 of the center-side filling material injection hole 27d or the receiving base-side filling material injection hole 27e after the filling is completed is closed. The opening and closing valves 28 of the unused center-side filling material injection holes 27d or the receiving base-side filling material injection holes 27e can be left open and used as air venting members. As described above, in the step of filling the filling and solidifying material 22, without using the filling material injection hole 27e of the receiving base-side block 20A, the filling and solidifying material 22 is injected using only the filling material injection hole 27d of the center-side block 20B, and it is also possible to confirm that the filling and solidifying material 22 flows out from the opening portion of the gap 21a between the receiving base portion 31c held on the upper surface portion 20a of the receiving base-side block 20A, and then finish the filling of the filling and solidifying material 22.By filling the filling and solidifying material 22 from the filling material injection hole 27d on the central part side, it becomes possible to smoothly vent air from the gap 21a between the receiving base part 31c held on the upper surface part 20a of the receiving base part side block 20A, and it becomes possible to effectively avoid the occurrence of air pockets in the filled filling and solidifying material 22.

[0086] Also, in this embodiment, the plurality of PCa concrete blocks 20A, 20B, 20C arranged continuously in the vertical and horizontal directions are preferably provided adjacent to each other in the axial direction of the tunnel of the existing invert structure 40 formed in advance as described above. While switching from the on-off valve 28 of the filling material injection hole 27d on the central part side located on the existing invert structure 40 side to the on-off valve 28 of the filling material injection hole 27d on the central part side located on the wife side, the filling and solidifying material 22 is injected, and while switching from the on-off valve 28 of the filling material injection hole 27e on the receiving base part side located on the existing invert structure 40 side to the on-off valve 28 of the filling material injection hole 27e on the receiving base part side located on the wife side, the filling and solidifying material 22 is injected. As described above, after switching from the filling material injection hole 27d of the central part side block 20B on the existing invert structure 50 side to the filling material injection hole 27d of the central part side block 20B on the wife side and injecting the filling and solidifying material 22 halfway, it is also possible to further switch from the filling material injection hole 27e of the receiving base part side block 20A on the existing invert structure 50 side to the filling material injection hole 27e of the receiving base part side block 20A on the wife side and inject the filling and solidifying material 22.

[0087] In each of the filling material injection holes 27d on the central part side and the filling material injection holes 27e on the pedestal part side, as described above, the on-off valve 28 can be attached in a state of protruding upward from the upper surface parts of a plurality of PCa concrete blocks 20A and 20B arranged longitudinally and horizontally connected by screwing the male screw part 28b to the female screw member 27a fixed to the intermediate part in the penetrating direction of the filling material injection hole 27d on the central part side or the filling material injection hole 27e on the pedestal part side. Thereby, the operation of detachably connecting the injection hose can be easily performed by the work on the upper surface parts 20a of the PCa concrete blocks 20A, 20B, and 20C.

[0088] And in the present embodiment, as shown in FIGS. 1 and 2, the invert part structure body 10 having the above-described configuration can form an invert part structure body 50 over the entire transverse direction that constitutes the invert part covering work body 32 integrally by being 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 as the one-side regions.

[0089] That is, the invert part structure 50 across the entire width is provided across the entire width in the tunnel's transverse direction in the invert part 33 of the mountain tunnel, and is a structure using PCa concrete blocks 20A, 20B, and 20C that constitutes the invert part covering structure 32. Each of the PCa concrete blocks 20A, 20B, and 20C is formed as a hexahedral block having a curved upper surface part 20a and a curved lower surface part 20b so as to have a curved shape along the cross-sectional shape of the invert part covering structure 32, as described above. As shown in FIGS. 1 and 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, and 20C are arranged continuously in the transverse direction of the tunnel while maintaining gaps 21a and 21b between the lower end receiving parts 31c of the adjacent side wall part covering structures 31a and between the adjacent PCa concrete blocks, and are installed in the invert part 33. Also in the axial direction of the tunnel, they are arranged continuously while maintaining a gap 21b between the adjacent PCa concrete blocks 20A, 20B, and 20C and are installed in the invert part 33, whereby one side block group 20X and the other side block group 20Y are formed. And in the central part in the transverse direction of the tunnel, a space part 51 is maintained between the one side block group 20X and the other side block group 20Y. The plurality of PCa concrete blocks 20A, 20B, and 20C arranged continuously vertically and horizontally in the one side block group 20X and the other side block group 20Y are integrated through a filling and solidifying material 22 filled and hardened in the gap 21a between the adjacent receiving parts 31c, the gap 21b between the adjacent PCa concrete blocks 20A, 20B, and 20C, the space part 51 between the one side block group 20X and the other side block group 20Y, and the gap 21c below the hexahedral lower surface part communicating with these gaps 21a, 21b, and the space part 51, so as to constitute the invert part covering structure 32.

[0090] In addition, in the present embodiment, the gap 21a between the adjacent receiving base portions 31c filled with the filled solidifying material 22 and the gap 21b between the adjacent PCa concrete blocks 20A, 20B, 20C preferably have a gap width of 15 to 30 mm, and the interval portion 51 between the one-side block group 20X and the other-side block group 20Y preferably has an interval width of 100 to 130 mm.

[0091] Furthermore, in the present embodiment, the plurality of PCa concrete blocks 20A, 20B, 20C arranged longitudinally and horizontally in the one-side block group 20X and the other-side block group 20Y respectively are arranged in an inverted U shape such that the gap 21b between the PCa concrete blocks adjacent in the transverse direction of the tunnel and the gap between the PCa concrete blocks adjacent in the axial direction of the tunnel, both filled with the filled solidifying material 22, are preferably linearly continuous, and are installed in the invert portion 33.

[0092] Furthermore, in the present embodiment, on the central-side surface of the PCa concrete block (central-side block) 20B located on the most central side of the one-side block group 20X facing the interval portion 51 and on the central-side surface of the PCa concrete block (central-side block) 20B located on the most central side of the other-side block group, as shown in FIG. 15 for example, unevenness 52 for improving the adhesion to the filled solidifying material 22 is preferably formed.

[0093] The unevenness 52 for improving the adhesion to the filling and solidifying material 22 is preferably formed on the transverse direction opposing surfaces 20d facing each other across the held gaps 21a and 21b in each PCa concrete block 20 arranged in a continuous manner in the transverse direction of the tunnel while holding the gaps 21a and 21b between the receiving base portion 31c at the lower end of the adjacent side wall covering member 31a and between the adjacent PCa concrete blocks 20, and installed in the invert portion 33. The unevenness 52 for improving the adhesion to the filling and solidifying material 22 can also be formed on the axial direction opposing surfaces 20c facing each other across the held gap 21b in each PCa concrete block 20 arranged in a continuous manner in the axial direction of the tunnel while holding the gap 21b between the adjacent PCa concrete blocks 20, and installed in the invert portion 33.

[0094] Also, in the present embodiment, it is preferable that the PCa concrete block (central portion side block) 20B located on the most central portion side of the one-side block group 20X and the PCa concrete block (central portion side block) 20B located on the most central portion side of the other-side block group 20Y are connected via a long bolt member (not shown). Thereby, it becomes possible to ensure the installation accuracy of the one-side block group 20X and the other-side block group 20Y, and it also becomes possible to ensure the shear strength of the portion between these block groups 20X and 20Y.

[0095] In this embodiment, the invert part structure 50 across the entire width of the tunnel described above can be formed by the following construction method. That is, in this embodiment, the construction method of the invert part structure 50 is such that in one 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 while maintaining gaps 21a, 21b between the lower end receiving part 31c of the adjacent side wall covering member 31a and between the adjacent PCa concrete blocks 20A, 20B, 20C, and are installed in the invert part 33. Also, in the axial direction of the tunnel, they are arranged in series while maintaining a gap 21b between the adjacent PCa concrete blocks 20A, 20B, 20C and installed in the invert part 33, thereby forming one-side block group 20X; a step of filling and curing the solidifying material 22 in the gap 21a between the plurality of PCa concrete blocks 20A, 20B, 20C of the one-side block group 20X arranged in series vertically and horizontally and the adjacent receiving part 31c, the gap 21b between the adjacent PCa concrete blocks 20A, 20B, 20C, and the gap 21c below the hexahedral lower surface part communicating therewith; in 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 while maintaining gaps 21a, 21b between the lower end receiving part 31c of the adjacent side wall covering member 31a and between the adjacent PCa concrete blocks 20A, 20B, 20C, and are installed in the invert part 33. Also, in the axial direction of the tunnel, they are arranged in series while maintaining a gap 21b between the adjacent PCa concrete blocks 20A, 20B, 20C and installed in the invert part 33, thereby forming the other-side block group 20Y; a step of the plurality of PCa concrete blocks 20A, 20B, 20C of the other-side block group 20Y arranged in series vertically and horizontally, the gap 21a between the adjacent receiving part 31c, the adjacent PCa concrete blocks 20A, 20B,In addition to the gap 21b between the 20C and the gap 21c below the hexahedral lower surface portion communicating therewith, a step of filling and curing the filling and curing material 22 is also included in the spaced portion 51 between the one-side block group 20X and the other-side block group 20Y. Thus, the invert portion structure 50 that is provided over the entire cross-sectional direction of the tunnel and constitutes the invert portion covering structure 32 can be easily formed.

[0096] For the invert portion structure 50 over the entire cross-sectional direction, for example, when it is possible to perform construction by blocking the passage of the mountain tunnel 30 for a long period of time, it can also be formed by simultaneously constructing the areas on both sides without constructing one area at a time.

[0097] According to the invert portion structure 10 of the present embodiment having the above-described configuration, by using the PCa concrete blocks 20 (20A, 20B, 20C) having an appropriate weight and size that can be easily manufactured in a factory or the like, it can be easily formed without much labor and can be installed more quickly as a component of the invert portion covering structure 32 that is continuously provided with the covering structure 31 of the upper arch-shaped portion 31b from the side wall portion 31a of the tunnel.

[0098] That is, according to the present embodiment, in the invert part structure 10, the PCa concrete block 20 constituting the invert part structure has, for example, a hexahedral shape with a curved upper surface part 20a and a curved lower surface part 20b, where the horizontal width x is about 1385 to 1435 mm, the vertical width y is about 730 mm, and the height z is about 500 mm, and has a weight of about 1300 kg. Compared with the conventional precast concrete invert concrete member with a large and complex weight and shape, it has an appropriate weight, size, and shape, so that it can be efficiently manufactured. In addition, the workability during lifting and transportation is improved, and the ease of handling during lifting and installation is also improved, so that each PCa concrete block 20 can be accurately installed at a predetermined position with an interval. Further, since the bolt insertion and screwing hole 25 having the large trumpet-shaped recess 25b and the small trumpet-shaped recess 25c is formed, it is possible to accurately and easily adjust the height of each PCa concrete block 20 by the height adjustment bolt 26. Thereby, the invert part 33 can be formed with high precision and easily so that the upper surface of the invert part 33 is convex downward and becomes a flat curved surface. Furthermore, it is possible to easily fill the filling and solidifying material 22 from the upper surface part 20a side of the block 20 through the filling material injection hole 27 having the upper side trumpet-shaped recess 27b and the lower side trumpet-shaped recess 27c.

[0099] Furthermore, by simply injecting and curing the filling and solidifying agent into the gaps and intervals between the PCa concrete blocks 20 installed adjacent to each other vertically and horizontally, these PCa concrete blocks 20 can be firmly integrated, so that it can be easily formed. Therefore, as a component of the invert part lining 32 provided continuously with the lining 31 of the upper arch-shaped part 31b from the side wall part 31a of the tunnel, it can be installed more quickly and easily.

[0100] Note that the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the invert portion structure of the present invention is not limited to the construction of adding a lining to the invert portion in a mountain tunnel where the lining covering the inner wall surface of the tunnel is formed only in the region from the side wall portions on both sides to the upper arch-shaped portion and is not formed in the invert portion. When newly forming a mountain tunnel, it can be adopted in the construction of providing a lining over the entire circumference including the invert portion on the inner wall surface of the tunnel, or in the construction of remodeling the lining of the invert portion already provided in a mountain tunnel and reinstalling a new lining for the invert portion.

Explanation of Reference Numerals

[0101] 10 Invert portion structure 10a Flange arrangement recess 10A Spouse-side end face portion 10B Center-side end face portion 20, 20’ PCa concrete block 20a Upper face portion 20b Lower face portion 20c Axial direction opposing face 20d Transverse direction opposing face 20e Notch recess 20f, 20g Axial direction connection portion 20A Pedestal portion side block 20B Center portion side block 20C Intermediate portion block 20D Transverse direction block row 20E Outer PCa concrete block 20F Inner PCa concrete block 20X One-side block group 20Y Other-side block group 21a Gap between the pedestal portion 21b Gap between adjacent PCa concrete blocks 21c Gap below the lower face portion 21d Gap with the existing invert portion structure 22 Filling and solidifying material 23 Bolt box 24 female screw anchor 25 bolt insertion and fastening hole 25a female screw member (nut member) 25b large trumpet-shaped recess 25c small trumpet-shaped recess 26 height adjustment bolt 26a lower end portion 26b ground adjuster 26c filling bottom surface portion 26d upper end portion 27 filling material injection hole 27a female screw member 27b upper side trumpet-shaped recess 27c lower side trumpet-shaped recess 27d filling material injection hole on the central side 27e filling material injection hole on the pedestal side 28 on-off valve 28a handle portion 29a transverse direction spacer jig 29b axial direction spacer jig 29c hanging jig 30 mountain tunnel 30a chassis portion 31 lining work 31a side wall portion (side wall lining work) 31b arch-shaped portion 31c pedestal portion 32 invert portion lining work 33 invert portion 35 H-shaped steel 36 temporary fixing means 36a hole-in anchor 36b cable body 36c expansion and contraction adjustment means 37 connecting portion structure of PCa concrete block 40 existing invert portion structure 41a upper surface belt plate-shaped formwork 41b side portion belt plate-shaped formwork 41c central side belt plate-shaped formwork 42 air vent hose 50 invert portion structure of the entire cross-sectional direction of the tunnel The interval part between the one-side block group and the other-side block group b The gap below the lower surface part

Claims

1. A PCa concrete block used for forming an invert structure body that is provided in at least one side region in the transverse direction of a tunnel in the invert part of a mountain tunnel and constitutes an invert covering structure body, while maintaining a gap filled with a filling and solidifying material between the pedestal part at the lower end of the adjacent side wall covering structure body and between the adjacent PCa concrete blocks, it is arranged continuously in the transverse direction of the tunnel, and also in the axial direction of the tunnel, while maintaining a gap filled with a filling and solidifying material between the adjacent PCa concrete blocks, and is arranged continuously and vertically and horizontally to be installed in the invert part, it is formed as a hexahedron block having a curved upper surface part and a curved lower surface part with a curved shape along the cross-sectional shape of the invert covering structure body, and having a pair of flat axial direction opposing surfaces in the front and rear and a pair of flat transverse direction opposing surfaces on the left and right, on the four side parts of the upper surface part of the hexahedron shape, a bolt box or a female screw anchor for connecting the adjacent PCa concrete blocks using a bolt member is embedded and fixed, and bolt insertion and screwing holes penetrating the hexahedron shape in the vertical direction are arranged at each corner part of an isosceles triangle shape and formed at three locations, in each bolt insertion and screwing hole, a female screw member for screwing a height adjustment bolt is fixed to a lower part than the intermediate part in the vertical direction, and a large trumpet-shaped recess that expands in diameter upward from the part where the female screw member is fixed and opens to the upper surface part of the PCa concrete block is formed, and a small trumpet-shaped recess that expands in diameter downward from the part where the female screw member is fixed and opens to the lower surface part of the PCa concrete block is formed, a PCa concrete block for an invert structure body.

2. The PCa concrete block for an invert structure body according to Claim 1, wherein the three bolt insertion and screwing holes are arranged at each corner part of the isosceles triangle shape with the bottom side part parallel to and on one side of the axial direction opposing surface and the top part on the other side of the axial direction opposing surface on the upper surface part of the PCa concrete block.

3. The PCa concrete block for an invert portion structure according to claim 1 or 2, wherein the center of gravity of the PCa concrete block is arranged inside the isosceles triangle shape when viewed from the upper surface portion side of the PCa concrete block.

4. The PCa concrete block for an invert portion structure according to claim 3, wherein the center of gravity of the PCa concrete block is arranged at the centroid position of the isosceles triangle shape when viewed from the upper surface portion side of the PCa concrete block.

5. The PCa concrete block for an invert portion structure according to claim 1 or 2, wherein a filler injection hole penetrating the hexahedron shape in the vertical direction is formed by being disposed at the central portion of the upper surface portion.

6. The PCa concrete block for an invert portion structure according to claim 1 or 2, wherein a spacer jig for maintaining a gap with a predetermined interval width between each of the pair of flat axial direction opposing surfaces and the pair of flat transverse direction opposing surfaces of the hexahedron shape and the other opposing surfaces facing each other is attached.

7. The PCa concrete block for an invert portion structure according to claim 1 or 2, wherein a plurality of lifting jigs used when lifting each of the PCa concrete blocks are embedded and fixed on the upper surface portion of the hexahedron shape.

Images