JP7764049B2 - Arch-shaped precast concrete slab connection structure - Google Patents

Description

The present invention relates to a connecting structure for arch-shaped precast concrete slabs.

Conventional examples of this type of arch-shaped precast slab connection structure include a snow shelter, an arch-shaped hollow structure constructed by connecting and fastening the tops of left and right unit panels of arch-shaped precast slabs with top connectors (e.g., Patent Document 1); an arch-shaped culvert, an arch-shaped hollow structure constructed by fastening the tops of left and right arch-shaped unit slabs of arch-shaped precast slabs with PC steel rods (e.g., Patent Document 2); an arch-shaped hollow structure constructed by using curved concrete arch-shaped precast slabs divided into two halves circumferentially around an arch-shaped tunnel, with interlocking steps formed at the top ends of the left and right arch-shaped precast slabs and fastened with bolts inserted through the steps (e.g., Patent Document 3); and an arch-shaped hollow structure constructed by fastening the top ends of left and right arch-shaped precast slabs with steps consisting of convex and concave portions that fit alternately and are fastened with bolts inserted through the convex and concave portions (e.g., Patent Document 4).

In Patent Document 1, the tops of the left and right unit panels are fastened with top connectors in the left-right direction (circumferential direction of the unit panels); in Patent Document 2, the tops of the left and right arch-shaped unit panels are fastened with PC steel rods in the left-right direction; in Patent Document 3, the tops of the left and right arch-shaped precast panels are fastened with double-threaded bolts in the front-to-back direction; and in Patent Document 4, the tops of the left and right arch-shaped precast panels are fastened and connected with bolts in the front-to-back direction. In all of these cases, if the left and right tops become misaligned, the misalignment cannot be corrected with connectors or the like.

For example, in Patent Document 3, the stepped holes through which the two threaded bolts are inserted are formed sufficiently larger than the threaded bolts themselves to allow for smooth insertion. Therefore, when a force is applied that presses down on the top of one of the left and right arch-shaped precast slabs, the gap between the stepped hole and the two threaded bolts causes the top of one of the left and right arch-shaped precast slabs to lower than the top of the other arch-shaped precast slab, potentially creating a step at the tops of the left and right arch-shaped precast slabs.

In addition, to insert both threaded bolts in the forward and backward directions into the stepped holes in the stepped sections of the left and right arch-shaped precast slabs, it was necessary to slide both threaded bolts lengthwise to insert them into the stepped holes, which was a time-consuming task when done close to the inner surface of the tunnel.

Furthermore, with a connection structure using double-threaded bolts, it was necessary to create unevenness at the ends of the arch-shaped precast slabs, and only the circumferential divisions could be connected.

Furthermore, in conventional connecting structures using double-ended threaded bolts, while the double-ended threaded bolts could be pulled out and removed from the longitudinal ends of arch-shaped precast slabs arranged side by side in the longitudinal direction, they could not be pulled out from intermediate arch-shaped precast slabs, making it difficult to easily replace only intermediate arch-shaped precast slabs for repairs, etc.

Japanese Unexamined Patent Publication No. 2-157307 Japanese Patent Application Laid-Open No. 2000-337092 Japanese Patent Application Publication No. 5-295992 Japanese Patent Application Laid-Open No. 2005-315029

The present invention aims to solve the above problems by providing a connecting structure for arch-shaped precast slabs that allows the height of the ends of the arch-shaped precast slabs to be matched, and also aims to provide a connecting structure for arch-shaped precast slabs that is highly versatile and allows for easy connecting work.

The invention of claim 1 is characterized in that, in a connection structure for arch-shaped precast slabs in which the abutting surfaces of adjacent ends are butted together to form an arch shape, attachment members are provided that are attached to the arch-shaped precast slabs from the inner surface side to prevent misalignment of the adjacent ends.

The invention of claim 1 is characterized in that the arch-shaped precast plate is divided circumferentially, and the ends of one and the other adjacent arch-shaped precast plates are fitted together using convex and concave portions, and through holes are formed in the width direction of the arch-shaped precast plate that are continuous with the convex portions of the ends of the one and the other arch-shaped precast plates, bolt members are inserted into the continuous through holes in the width direction of the one and the other arch-shaped precast plates, and the ends are connected by this bolt member, the bolt members are loosely inserted into the through holes from the inner side to the outer side of the arch-shaped precast plate, and abutment portions are provided on the outer surface side of the arch-shaped precast plate that abut against the outer surface side of the continuous through holes of the arch-shaped precast plate, and a pressing member is provided as the mounting member that presses the bolt member toward the outer surface of the arch-shaped precast plate.

The invention of claim 2 is characterized in that the bolt member comprises a main body on which the abutment portion is provided and male screw portions provided on both ends of the main body, a recess communicating with the through hole is formed on the inner surface of the end, and a nut is screwed onto the male screw portion protruding into this recess.

The invention of claim 3 is characterized in that the bolt member comprises a main body having the abutment portion and male screw portions provided on both ends of the main body, a female screw hole is provided between the inner surface of the arch-shaped precast plate and the through hole, and the pressing member is a bolt that is screwed into the female screw hole and whose tip side abuts against the inner surface side of the arch-shaped precast plate of the main body.

According to the configuration of claim 1, by attaching the mounting members from the inner surface of the arch-shaped precast slab, it is possible to prevent misalignment of adjacent ends.

According to the configuration of claim 1 , when the pressing member presses the bolt member toward the outer surface of the arch-shaped precast slab, the abutment portion of the bolt member abuts against the outer surface sides of the through holes connected to the convex portions of both arch-shaped precast slabs, and the outer surfaces of the through holes in both convex portions are pressed by the bolt member, thereby aligning the convex portions in the inner and outer directions of the arch-shaped precast slab. This prevents the occurrence of a step between the ends of one and the other circumferentially adjacent arch-shaped precast slabs.

According to the configuration of claim 2 , the abutment portion provided on the main body of the bolt member presses the outer side of the through holes of both convex portions, thereby aligning both convex portions in the inner and outer surface directions of the arch-shaped precast plate, preventing the occurrence of steps between the ends of one and the other adjacent arch-shaped precast plates in the circumferential direction, and in this state, a nut can be screwed onto the male thread portion to connect the ends of the arch-shaped precast plates.

According to the third aspect of the present invention, when the bolt is screwed in, the tip of the bolt presses the body, and the body presses the outer surface of the arch-shaped precast slab in the through-hole.

1 is a cross-sectional view of an arch-shaped hollow structure showing a first embodiment of the present invention. FIG. 10 is a bottom view of the top of the arch-shaped precast slab in the joined state. FIG. 10 is a perspective view of the top of the arch-shaped precast slab. FIG. 10 is a perspective view of the top of the arch-shaped precast slab in the joined state. FIG. FIG. FIG. 10 is a cross-sectional view of the top portion of the same as above, with the bolt member inserted therethrough. This is a cross-sectional view of the top of the same structure, in which the abutment portion of the bolt member is abutted against the outer surface of the arch-shaped precast slab of the through hole by the pressing means. FIG. 10 is a cross-sectional view of the top of a modified through-hole according to the first embodiment. This is a bottom view of the top of an arch-shaped precast slab in a joined state, showing Reference Example 1 of the present invention. FIG. 10 is a bottom view of the top of the arch-shaped precast slab. 12A and 12B are cross-sectional views of the top portion of the same, where FIG. 12A shows the state before connection and FIG. 12B shows the state after connection. FIG. FIG. FIG. FIG. 6 is a cross-sectional view of an arched tunnel showing a second embodiment of the present invention.

Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the embodiments described below do not limit the scope of the present invention as defined in the claims. Furthermore, not all of the configurations described below are necessarily essential requirements for the present invention.

Embodiments of the present invention will now be described with reference to the accompanying drawings. Figures 1 to 9 show embodiment 1 of the present invention. Figure 1 shows a cross section of an arch-shaped hollow structure 1, with concrete foundations 3, 3 provided on both sides of the road surface 2, and a pair of left and right arch-shaped precast slabs 11, 21 made of precast concrete assembled into an arch shape and installed.

Specifically, bearing surfaces 4 are provided on the concrete foundations 3, 3, and mounting portions 5 protrude from the outside of these bearing surfaces 4. The lower ends 11K, 21K of the arch-shaped precast slabs 11, 21 are placed on the bearing surfaces 4, 4. The lower parts of the arch-shaped precast slabs 11, 21 are fixed to the mounting portions 5, 5 by fixing means 6, and the upper ends of each arch-shaped precast slab 11, 21 abut against each other. The fixing means 6 includes two threaded bolts 6A extending in the width direction of the road surface that are inserted through the lower parts of the arch-shaped precast slabs 11, 21 and the mounting portions 5, 5, and nuts 6B, 6B that thread onto both ends of the two threaded bolts 6A.

The arch-shaped precast slabs 11, 21 on one side and the other (right and left) are arranged in parallel along the length of the road surface 2, with the length of the road surface 2 aligned along the width, and the end faces 12, 12, 22, 22 at both ends in the width direction are butted together. The arch-shaped precast slabs 11, 21 are formed to have the same width along the length of the road surface.

As shown in the bottom view of Figure 2, the top 13 located at the top center of the hollow structure of the right arch-shaped precast slab 11 (one of the left and right) has a roughly square convex portion 61 on the other side in the width direction, and a roughly square concave portion 62 on one side in the width direction corresponding to this convex portion 61, and a step surface 63 is formed between the convex portion 61 and the concave portion 62 in the direction perpendicular to the width direction of the arch-shaped precast slab 11.

The width of the convex portion 61 and the width of the concave portion 62 are approximately the same, with the tip surface of the convex portion 61 being the tip abutment surface 64 and the bottom surface of the concave portion 62 being the base abutment surface 65.

The top 23, located at the top center of the hollow structure of the left arch-shaped precast slab 21, has a convex portion 61A on one side in the width direction and a concave portion 62A on one side in the width direction corresponding to this convex portion 61A. A step surface 63 is formed between the convex portion 61A and the concave portion 62A in a direction approximately intersecting the width direction of the arch-shaped precast slab 21.

The width of the convex portion 61A and the width of the concave portion 62A are approximately the same, with the tip surface of the convex portion 61A being the tip abutment surface 64A and the bottom surface of the concave portion 62A being the base abutment surface 65A.

Then, the tip abutment surface 64 of one arch-shaped precast slab 11 is abutted against the base abutment surface 65A of the other arch-shaped precast slab 21, and the base abutment surface 65 of one arch-shaped precast slab 11 is abutted against the tip abutment surface 64A of the other arch-shaped precast slab 21. The step surfaces 63, 63 of the tops 13, 23 are also abutted against each other.

In addition, adjacent arch-shaped precast slabs 11, 21 along the length of the walkway road surface 2 are installed with their end faces 12, 22 aligned.

Next, we will explain the connecting structure 70 for the apexes 13, 23, which are the ends of the pair of left and right arch-shaped precast slabs 11, 21. Through holes 71, 71 are formed in the convex portions 61, 61A of the left and right arch-shaped precast slabs 11, 21 in the width direction of the arch-shaped precast slabs 11, 21. Then, with the apexes 13, 23 in a concave-convex fit, the through holes 71, 71 of the convex portions 61, 61A are connected.

As shown in Figure 6 and other figures, the through hole 71 has inner surfaces 72, 72 that taper from the inner surfaces 11U, 21U of the arch-shaped precast slabs 11, 21 toward the outer surfaces 11G, 21G, an upper surface portion 73 connecting the upper parts of these inner surfaces 72, 72, and a lower surface portion 74 connecting the lower parts of these inner surfaces 72, 72, and has a cross section that is a symmetrical isosceles trapezoid.

The inner surface of the through hole 71 can be constructed by forming a concrete surface using a die, or by insert molding an isosceles trapezoidal pipe material, as described below.

Recesses 76, 76 opening onto inner surfaces 11U, 21U are provided in the widthwise center of protrusions 61, 61A. These recesses 76, 76 divide the through hole 71 into a through hole end surface side 171 on the end surfaces 12, 22 side and a through hole step surface side 171A on the step surfaces 63, 63 side. These through hole end surface side 171 and through hole step surface side 171A open onto the fixing surfaces 77, 77 of recess 76, with the through hole end surface sides 171, 171 opening onto end surfaces 12, 22 and the through hole step surface side 171A opening onto step surfaces 63, 63. The through hole end surface side 171 is one through hole dividing portion, and the through hole step surface side 171A is the other through hole dividing portion.

The recess 76 is roughly box-shaped, with anchoring surfaces 77, 77 provided on both sides of the width of the arched precast slabs 11, 21 of the recess 76. The anchoring surfaces 77, 77 on both sides are parallel, and as shown in Figure 6, the distance between the side surfaces on both sides tapers toward the outer surface.

The recess 76 opens onto the inner surfaces 11U and 21U and is provided with a lid 78 (Figure 2) that closes this opening. The lid 78 is removably attached to the inner surfaces 11U and 21U by means of screws 79, which serve as attachment and detachment means.

A bolt member 80 (Figure 5) is provided that is inserted into the through-hole 71 to connect the ends of the left and right arch-shaped precast slabs 11, 21. This bolt member 80 is made of a hard material such as metal and integrally comprises a main body 81 that engages with the through-hole 71 and male screw portions 81N, 81N that serve as threaded rods on both ends of the main body 81.

The main body 81 has side portions 82, 82 that taper upward to correspond to the through hole 71, an upper surface portion 83 that serves as an abutment connecting the upper parts of the side portions 82, 82, and a lower surface portion 84 that connects the lower parts of the side portions 82, 82. It has an isosceles trapezoidal cross section, the upper surface portion 83 has the same width as the upper surface portion 73 of the through hole 71, the included angle between the side portions 82, 82 is equal to the included angle between the inner surfaces 72, 72 of the through hole 71, the side portions 82 are shorter than the inner surfaces 72 of the through hole 71, and the height of the main body 81 is smaller than the height of the through hole 71.

The outer surface of the arch-shaped precast plates 11, 21 of the main body 81 is the upper surface portion 83, and the inner surface of the arch-shaped precast plates 11, 21 of the main body 81 is the lower surface portion 84.

As a result, the bolt member 80 can be loosely inserted into the through-hole 71, which has a smaller cross-section than the main body 81, making the insertion of the bolt member 80 easy.

The system also includes a pressing means 85 (Figure 8) that presses the bolt member 80 loosely inserted into the through-hole 71 toward the outer surfaces 11G, 21G of the arch-shaped precast slabs 11, 21.

The pressing means 85 has female threaded holes 86 formed in multiple locations (two locations) on the inner surfaces 11U and 21U (Figure 2), which communicate with the through-hole end surface side 171, which is one side of the through-hole, and the underside 74 of the through-hole stepped surface side 171A, which is the other side of the through-hole, and bolts 88 are threaded into the female threaded holes 86 from the inner surfaces 11U and 21U side.

By screwing in the bolt 88, the tip of the bolt 88 presses against the underside 84 of the main body 81, causing the main body 81 to fit into the upper part of the through-hole 71.

The bolt 88 is a pressing member that presses the bolt member 80 toward the outer surfaces 11G, 21G of the arch-shaped precast slabs 11, 21, and is also an attachment member that attaches the bolt member 80 to the arch-shaped precast slabs 11, 21 from the inner surfaces 11U, 21U of the arch-shaped precast slabs 11, 21.

The female screw hole 86 can be formed by insert molding a female cylindrical portion 87 into the arch-shaped precast slabs 11 and 21, with the female screw hole 86 provided within this female cylindrical portion 87. The female cylindrical portion 87 is made of a hard material such as metal.

When connecting the bolts, the tops 13, 23 of the left and right arch-shaped precast slabs 11, 21 are butted together, and the bolt members 80 are loosely inserted into the through-holes 71 between the recesses 76, 76 (Figure 7). Then, the male threads 81N, 81N at both ends are positioned in the recesses 76, 76, and the male threads 81N are inserted through the through-holes 89T of the anchoring plate 89. The anchoring plate 89 is then abutted against the anchoring surface 77, and the nut 90, which serves as the fixing means, is screwed onto the male threads 81N. This screwing is a temporary tightening.

After this, when the bolts 88, 88 are screwed in, the tips of the bolts 88, 88 press against the underside 84 of the main body 81, causing the approximately trapezoidal main body 81 to move toward the outer surfaces 11G, 21G, and the main body 81 fits into the upper part of the through-hole 71, as shown in Figure 8.

In this fitted state, the upper surface 83 of the main body 81 presses against the upper surface 73 of the through-hole end surface side 171 and the through-hole step surface side 171A of the arch-shaped precast slabs 11 and 21, aligning the height positions of the peaks 13 and 23 of both arch-shaped precast slabs 11 and 21. In other words, the upper surface 83 of the main body 81 abuts against the upper surface 73 of both the through-hole end surface side 171 and the through-hole step surface side 171A. After aligning the height positions of the peaks 13 and 23 of both arch-shaped precast slabs 11 and 21 in this way, the nut 90 is fully tightened.

In addition, in the fitted state, the pair of left and right side surfaces 82, 82 of the main body 81 fit into the pair of left and right inner surfaces 72, 72 of the through-hole 71, thereby aligning the arch direction positions of the arch-shaped precast slabs 11, 21 of the tops 13, 23. In this way, the left and right side surfaces 82, 82 and the top surface 83 of the main body 81 form fitting portions that fit into the upper part of the through-hole 71.

Figure 9 shows a modified version of the through hole 71, in which the through hole 71 is formed from a pipe material 75 formed in an isosceles trapezoidal shape.

This allows the through hole 71 to be formed without using a punching die, and the inner surface of the metal pipe 75 is smoother than the concrete surface, allowing the main body 81 of the bolt member 80 to be inserted and fitted smoothly. The pipe 75 also has a through hole corresponding to the female threaded hole 86, through which the bolt 88 is inserted.

In this way, in this embodiment, the connecting structure of the arch-shaped precast slabs 11, 21, which are connected by butting the tip abutment surface 64 and the base abutment surface 65A, and the base abutment surface 65 and the tip abutment surface 64A, which are the abutment surfaces of the adjacent end portions (peaks 13, 23), is provided with bolts 88 as mounting members that are attached to the arch-shaped precast slabs 11, 21 from the inner surfaces 11U, 21U of the arch-shaped precast slabs 11, 21 to prevent misalignment of the adjacent peaks 13, 23. By attaching the bolts 88 from the inner surfaces 11U, 21U of the arch-shaped precast slabs 11, 21, misalignment of the adjacent peaks 13, 23 can be prevented.

In this embodiment, the arch-shaped precast slabs 11, 21 are divided in the circumferential direction, and the peaks 13, 23 of the circumferentially adjacent arch-shaped precast slabs 11, 21 are fitted together by the convex portions 61, 61A and the concave portions 62, 62A. Through holes 71 are formed in the width direction of the arch-shaped precast slabs, connecting to the convex portions 61, 61A of the peaks 13, 23 of the arch-shaped precast slabs 11, 21. Bolt members 80 are inserted through the through holes 71, which are connected in the width direction of the arch-shaped precast slabs 11, 21. The tops 13, 23 are connected to each other by the member 80, and the bolt member 80 is loosely inserted into the through hole 71 so as to be movable from the inner surface 11U, 21U side of the arch-shaped precast slabs 11, 21 to the outer surface 11G, 21G side. An upper surface portion 83 is provided on the outer surface 11G, 21G side of the arch-shaped precast slabs 11, 21 of the bolt member 80, which serves as an abutment portion that abuts against the upper surface portion 73 on the outer surface 11G, 21G side of the arch-shaped precast slabs 11, 21 of the continuous through hole 71, and a pressing means 85 is provided to press the bolt member 80 toward the outer surface 11G, 21G side of the arch-shaped precast slabs 11, 21.

With the above configuration, when the pressing means 85 presses the bolt member 80 toward the outer surfaces 11G, 21G of the arched precast slabs 11, 21, the upper surface 83 of the bolt member 80 abuts against the upper surface 73 of the through hole 71 continuing to the convex portions 61, 61A of both arched precast slabs 11, 21, and the through hole 71 spanning both convex portions 61 , 61A is pressed by the bolt member 80, thereby aligning both convex portions 61, 61A in the inner and outer surface directions (thickness direction) of the arched precast slabs. This prevents steps from occurring between the ends of one and the other circumferentially adjacent arched precast slabs 11, 21.

In this embodiment, the bolt member 80 comprises a main body 81 having an upper surface portion 83 as an abutment portion, and male screw portions 81N provided on both ends of the main body 81. A recess 76 communicating with the through hole 71 is formed on the inner surfaces 11U, 21U of the end apexes 13, 23, and a nut 90 is screwed onto the male screw portion 81N protruding into this recess 76. Therefore, the upper surface portion 73 as an abutment portion provided on the main body 81 of the bolt member 80 presses against the outer surfaces 11G, 21G of the through hole 71 of both convex portions 61, 61A, thereby aligning the both convex portions 61, 61A in the inner and outer surface directions of the arch-shaped precast slabs, and preventing the occurrence of steps between the ends of one and the other adjacent arch-shaped precast slabs 11, 21 in the circumferential direction. In this state, the nut 90 can be screwed onto the male screw portion 81N to connect the ends of the arch-shaped precast slabs 11, 21.

In this embodiment, the bolt member 80 comprises a main body 81 with an upper surface 83 that serves as an abutment portion, and male thread portions 81N provided on both ends of the main body 81. The pressing means 85 comprises a female threaded hole 86 provided between the inner surfaces 11U, 21U of the arch-shaped precast slabs 11, 21 and the through hole 71, and a bolt 88 that is threaded into the female threaded hole 86 and whose tip abuts against the lower surface 84 of the main body 81 on the inner surface side of the arch-shaped precast slab. Therefore, when the bolt 88 is screwed in, the tip of the bolt 88 presses against the main body 81, and the main body 81 presses against the upper surface 73 on the outer surface side of the arch-shaped precast slab of the through hole 71.

As an effect of the embodiment described below, the through hole 71 narrows from the inner surface side of the arch-shaped precast slab to the outer surface side, and the bolt member 80 is provided with a main body 81 as a narrowing portion corresponding to the cross-sectional shape of the through hole 71. On the outer surface side of the arch-shaped precast slab, this main body 81 is provided with an upper surface portion 83 as an abutment portion that abuts against the upper surface portion 73 on the outer surface side of the arch-shaped precast slab of the through hole 71, and a pressing means 85 is provided to press the main body 81 toward the outer surfaces 11G, 21G, so that the main body 81 fits smoothly into the upper part of the through hole 71, and the two apexes 13, 23 are aligned.

In addition, the through hole 71 has inner surfaces 72, 72 that taper apart from each other from the inner surface 11U, 21U of the arch-shaped precast plate 11, 21 toward the outer surface 11G, 21G, and the main body 81 has side portions 82, 82 that taper apart toward the upper side, with the upper surface portion 83 abutting against the upper surface portion 73 and both side portions 82, 82 abutting against both inner surfaces 72, 72, so that the main body 81 fits into the upper part of the through hole 71, and therefore the convex portions 61, 61A are positioned in the thickness direction of the arch-shaped precast plate, and the tops 13, 23 are positioned circumferentially by this fitting.

In addition, multiple pressing means 85 are provided on the through hole end face side portion 171 and the through hole step face side portion 171A, which divide the through hole 71, so that the main body 81 can be pressed evenly to align the through hole end face side portion 171 and the through hole step face side portion 171A in the thickness direction of the arch-shaped precast plate.
[Reference example 1]

10 to 15 show Example 1 of the present invention, in which the same parts as in Example 1 are designated by the same reference numerals and their explanations are omitted. This example relates to a connecting structure 70A that can connect the ends of adjacent arch-shaped precast slabs 11, 21 in the circumferential direction or the end faces 12, 22 of adjacent arch-shaped precast slabs 11, 21 in the width direction.

Figures 10 and 11 show an example in which the butt surfaces of the apexes 13, 23, which are the ends of circumferentially adjacent arch-shaped precast slabs 11, 21, are butted together and connected.

Figure 10 also shows an example in which the end faces 12, 12, 22, 22 of adjacent arch-shaped precast slabs 11, 11, 21, 21 in the width direction are butted together and connected. When the end faces 12, 12, 22, 22 of adjacent arch-shaped precast slabs 11, 11, 21, 21 are butted together, a connecting groove 110 is formed between the adjacent arch-shaped precast slabs 11, 11, 21, 21.

As shown in Figure 14, the connecting member 111 is an attachment member that is inserted into the connecting groove 110 to connect adjacent arch-shaped precast slabs 11, 21. This connecting member 111 has a central connecting portion 112 that is a vertical plate of a uniform thickness, and approximately cylindrical spacing portions 113, 113 are integrally formed on both sides of this central connecting portion 112, and is made of a hard material such as metal.

The diameter, which is the thickness of the spacing portion 113, is larger than the thickness T of the longitudinal end portion 112T of the central connecting portion 112. The end portion 112T is the connection point between the central connecting portion 112 and the spacing portion 113. If the spacing portion 113 is not cylindrical, the thickness of the spacing portion 113 is the maximum dimension in the thickness direction of the central connecting portion 112.

The upper part of the connecting member 111 has a shape that tapers upward, and the upper part of the central connecting part 112 has sloped parts 114, 114 formed on both sides in the width direction, while the upper part of the spacing part 113 has a truncated cone shape and is formed with a tapered surface 115 that tapers upward.

Furthermore, a central upper surface portion 116A is formed on both sloped surfaces 114, 114, and a circular end upper surface portion 116B is provided above the tapered surface 115. The central upper surface portion 116A and end upper surface portions 116B, 116B form the upper surface portion 116 of the connecting member 111, and the central upper surface portion 116A and end upper surface portion 116B are located on the same plane. Furthermore, the upper surface portion 116 of the connecting member 111 and the lower surface portion 117 of the connecting member 111 are parallel to each other.

As shown in Figure 15, the embedded member 121 has a divided connecting groove 120, which divides the connecting groove 110 at the abutment surface. This embedded member 121 is roughly rectangular and made of a hard material such as metal. It is embedded and fixed in the arch-shaped precast slabs 11, 21 to correspond to the abutment surface.

The split connecting groove 120 comprises a central groove 122, which has a shape that roughly divides the central connecting portion 112 in two, and a spacing groove 123, into which the spacing portion 113 is inserted, which are connected to each other. By bringing a pair of embedding members 121, 121 together at their butt surfaces, the split connecting grooves 120, 120 are connected to form the connecting groove 110, into which the connecting member 111 is inserted.

The central groove 122 has a butt surface side opening 128 that opens to the butt surface and an inner surface side opening 129 that opens to the inner surfaces 11U and 21U, and has a substantially constant width corresponding to the thickness of the central connecting portion 112. The butt surface side opening 128 opens to the central surface 121S of the embedded member 121, and the inner surface side opening 129 opens to the lower surface 121K of the embedded member 121.

The spacing groove 123 is cylindrical, corresponding to the spacing portion 113. The upper portion of the central groove 122 is closed by the upper surface portion 126. The height of the connecting member 111 is equal to or greater than the depth of the connecting groove 110, and in this example, they are equal.

When a joint is provided between the butting surfaces, as shown in Figure 13, a joint (gap) is provided between the central surfaces 121S, 121S, so the length of the central connecting portion 112 is twice the length of the central groove portion 122 plus the dimensions of the joint.

In this example, between adjacent arch-shaped precast slabs 11, 21 in the circumferential direction, from the top of Figure 11, two embedded members 121, 121 are fixed to the abutting surfaces 65, 64A, two embedded members 121, 121 are fixed to the abutting surfaces 64, 65A, and two embedded members 121, 121 are fixed to the abutting surfaces 65, 64A.

As shown in Figure 11, embedded members 121 are fixed to the end faces 12, 12 that serve as abutting surfaces at the ends of adjacent arch-shaped precast slabs 11, 11 in the width direction, connecting the adjacent arch-shaped precast slabs 11, 11 at the end faces 12, 12. Embedded members 121 are fixed to the end faces 22, 22 that serve as abutting surfaces at the ends of adjacent arch-shaped precast slabs 21, 21 in the width direction, connecting the adjacent arch-shaped precast slabs 21, 21 at the end faces 22, 22.

As shown in Figures 10 and 13, the embedded member 121 has protruding insert bars 130 that serve as fixing protrusions. In this example, insert bars 130, 130 protrude outward from the left and right outer surfaces of the embedded member 121. The male threads of these insert bars 130 are threadedly engaged with female threads 130N formed on the outer surface of the embedded member 121 to secure it in place.

As shown in Figure 13 and elsewhere, the embedded members 121 are provided with a retaining structure 131 that prevents the connecting member 111 from slipping out of the connecting groove 110. This retaining structure 131 has through-holes 133, 133 drilled on both sides of a plate-shaped pressing member 132 that presses against the underside 117 of the connecting member 111. Bolts 134, 134 serving as fixing means are inserted through these through-holes 133, 133, and female threads 135 into which the bolts 134, 134 thread are formed on the underside 121K of the embedded members 121, 121.

Furthermore, as a modified example, as shown in Figure 12 , female screw holes 137, 137 serving as extraction member connecting portions are formed in the center of the spacing retaining portions 113, 113 on the underside portion 117 of the connecting member 111, and a bolt (not shown) serving as an extraction member with a male screw portion is screwed into this female screw hole 137, and the bolt can be pulled to extract the connecting member 111 from the connecting groove 110.

During the connecting operation, a connecting groove 110 is formed by embedded members 121, 121 located at the abutting surfaces of adjacent arch-shaped precast slabs 11, 21. The connecting member 111 is inserted into this connecting groove 110, and the inclined surfaces 114, 114 and tapered surface 115 allow for smooth insertion.

In addition, since this work can be done from the inner surfaces 11U, 21U of the arch-shaped precast slabs 11, 21, the insertion work can be carried out easily, and connecting members 111, which serve as mounting members, are attached to the arch-shaped precast slabs 11, 21 to prevent misalignment of the adjacent end portions, or apexes 13, 23.

In addition, a secure connection can be achieved by inserting the connecting member 111 into the connecting groove 110 until the lower surface 117 of the connecting member 111 is positioned at the lower surface 121K of the embedded member 121. Furthermore, after connection, the anti-slip structure 131 prevents the connecting member 111 from falling off.

In addition, partial repairs to the arch-shaped precast slabs 11, 21 may become necessary over time. For example, if one arch-shaped precast slab 11 needs to be replaced, the retaining members 132 on the top 13 and both end faces 12, 12 can be removed, and a bolt (not shown) acting as an extraction member can be threaded into the female threaded hole 137 on the exposed underside 117. The bolt can then be pulled to remove the connecting member 111 from the connecting groove 110, thereby releasing the connection. Furthermore, the lower ends 11K, 21K of the arch-shaped precast slabs 11, 21 are released from their fixing means 6, and the connection to the concrete foundation 3 is released.

In this way, one arch-shaped precast slab 11 can be removed from between multiple adjacent arch-shaped precast slabs 11, 11... After removal, a new arch-shaped precast slab 11 equipped with an embedded member 121 can be placed in the same location, and the top 13 and both end faces 12, 12 can be connected to the adjacent arch-shaped precast slabs 21, 11, 11 using connecting members 111, just as in the case of new installation.

In this embodiment , when the abutment surfaces 64, 65A, the abutment surfaces 65, 64, the end faces 12, 12 as abutment surfaces, and the end faces 22, 22 as abutment surfaces of the adjacent arch-shaped precast slabs 11, 21 are abutted against each other, the adjacent arch-shaped precast slabs 11, 21 are provided with divided connecting grooves 120, 120 that form connecting grooves 110 spanning between the adjacent arch-shaped precast slabs 11, 21, and the divided connecting grooves 120 have central grooves 122 that open to the abutment surfaces and the inner surfaces 11U, 21U of the arch-shaped precast slabs 11, 21, and The connecting member 111 has a spacing groove 123 that connects adjacent arch-shaped precast slabs 11, 21, and is provided with a connecting member 111 that is inserted into the connecting groove 120 to connect adjacent arch-shaped precast slabs 11, 21. This connecting member 111 integrally has a central connecting portion 112 that is inserted into the central groove 122 of adjacent arch-shaped precast slabs 11, 21 or adjacent arch-shaped precast slabs 11, 11, 21, 21 that are connected across the abutting surface, and spacing retaining portions 113, 113 that are provided on both sides of the central connecting portion 112 and are inserted into the spacing retaining grooves 123 of the arch-shaped precast slabs 11, 21 to maintain the spacing between the spacing retaining grooves 123, 123.

By adopting the above configuration, adjacent arch-shaped precast slabs 11, 21 or adjacent arch-shaped precast slabs 11, 11 or adjacent arch-shaped precast slabs 21, 21 can be connected by inserting a connecting member 111 into the connecting groove 110 spanning between the adjacent arch-shaped precast slabs 11, 21 while the abutting surfaces of the adjacent arch-shaped precast slabs 11, 21 are abutted together. This simplifies the connecting work and can be used to connect the ends of adjacent arch-shaped precast slabs 11, 21 in the circumferential direction, as well as to connect adjacent arch-shaped precast slabs 11, 11, 21, 21 in the width direction, making it highly versatile.

In this way, in this reference example, an embedded member 121 having a dividing connecting groove 120 and a spacing maintaining groove portion 123 is provided, and the embedded member 121 is embedded and fixed in the arch-shaped precast slabs 11, 21.Therefore, by embedding and fixing the embedded member 121 in the arch-shaped precast slabs 11, 21, the arch-shaped precast slabs 11, 21 having the dividing connecting groove 120 and the spacing maintaining groove portion 123 can be easily obtained.

In this way, this reference example is provided with a pressure member 132 that is placed on the inner surface 11U, 21U side of the arch-shaped precast slabs 11, 21 of the connecting member 111, and a bolt 134 that serves as a fixing means for fixing this pressure member 132 to the arch-shaped precast slabs 11, 21, so that the pressure member 132 can prevent the connecting member 111 from coming out after connection.

As an effect of the reference example, the upper part of the connecting member 111 has a shape that tapers from the inner surface 11U side toward the outer surface 11G side, and the shape tapers upward, so that it can be smoothly press-fitted into the connecting groove 110. Furthermore, if the height of the connecting member 111 is equal to the depth of the connecting groove 110, and the connecting member 111 is press-fitted until the lower surface portion 117 of the connecting member 111 is positioned on the lower surface 121K of the embedding member 121, it can be confirmed that the upper surface portion 116 of the connecting member 111 has reached the upper surface portion 126 of the connecting groove 110.

In addition, the embedded member 121 is provided with a protruding insert 130, which serves as a protrusion for protruding, allowing the embedded member 121 to be integrally fixed to the concrete arch-shaped precast slabs 11 and 21.

Furthermore, a detachable pressing member 132 that presses the underside 117 of the connecting member 111 prevents the connecting member 111 from slipping out. The pressing member 132 can be removed to pull out the connecting member 111. At this time, the connecting member 111 can be easily pulled out using the female screw hole 137, which serves as the pull-out member connection portion.

In addition, the connecting member 111 has a shape that is symmetrical with respect to the central plane in the thickness direction and the central plane in the length direction, so when inserting the connecting member 111 into the connecting groove 110, the insertion operation can be easily performed without having to worry about the orientation of the connecting member 111.

Figure 16 shows a cross section of an arched tunnel 31 according to a second embodiment of the present invention. This arched tunnel 31 has an existing arched structure 32 assembled in an arch shape, and the inner surface of this arched structure 32 is the inner surface 33 of the existing tunnel 31.

Side walls 35, 35 made of, for example, cast-in-place concrete are constructed at the bottom of the left and right inner surfaces 33 of the tunnel 31 that rise above the road surface 34. In addition, a pair of left and right arch-shaped precast slabs 11, 21 made of precast concrete are assembled into an arch shape and installed on the inner surface 33 of the arch-shaped tunnel 31 as decorative slabs having a shape that divides the tunnel 31 into two circumferentially, and the lower ends 11K, 21K of each arch-shaped precast slab 11, 21 are supported by the side walls 35, 35, respectively, and the upper ends of each arch-shaped precast slab 11, 21 abut against each other. The space between the lower ends 11K, 21K of the precast slabs 11, 21 and the upper surfaces 53J of the side walls 35 is filled with a hardening agent 43 such as concrete or mortar. As the hardening agent 43 hardens, the lower ends of the precast slabs 11, 21 are rigidly connected to the side walls 35, forming an arched hollow structure 36 comprising the left and right arched precast slabs 11, 21 and the side walls 35. The side walls 35 are mounting portions for attaching the lower portions of the arched precast slabs 11, 21. 35U denotes the inner surface of the side wall 35, and 35J denotes the upper surface of the side wall 35.

The arch-shaped precast slabs 11, 21 are arranged in parallel along the tunnel length, with the tunnel length aligned with the width, and the end faces 12, 22 at both ends in the width direction are butted together. The arch-shaped precast slabs 11, 21 are formed to have the same width along the tunnel length. The arch-shaped precast slabs 11, 21 are connected by connecting structures 70, 70A, as in Example 1 and Reference Example 1 .

In this way, in this embodiment, the connection structure of arch-shaped precast slabs 11, 21, which are connected by butting the tip abutment surface 64 and the base abutment surface 65A of the adjacent end portions (peaks 13, 23), the base abutment surface 65 and the tip abutment surface 64A together, the end surfaces 12, 12 together, and the end surfaces 22, 22 together, is provided with connecting members 111 as attachment members that are attached to the precast slabs 11, 21 from the inner surfaces 11U, 21U of the precast slabs 11, 21 to prevent misalignment of the adjacent peaks 13, 23. By attaching the connecting members 111 from the inner surfaces 11U, 21U of the precast slabs 11, 21, misalignment of the adjacent peaks 13, 23 can be prevented.

In this embodiment, the arched precast slabs for the tunnel are installed on the inner surface 33 of the arched tunnel 31 and connected by butting together the tip abutment surface 64 and the base abutment surface 65A, and the base abutment surface 65 and the tip abutment surface 64A, which are the abutment surfaces of the adjacent end portions of the apexes 13 and 23. To prevent misalignment of the adjacent apexes 13 and 23, bolts 88 are provided as mounting members that attach to the arched precast slabs 11 and 21 from the inner surface 11U and 21U sides of the arched precast slabs 11 and 21. By attaching the bolts 88 from the inner surface 11U and 21U sides of the arched precast slabs 11 and 21, misalignment of the adjacent apexes 13 and 23 can be prevented.

In this embodiment, in the connection structure of the arch-shaped precast slabs for the tunnel, which are installed on the inner surface 33 of the arch-shaped tunnel 31 and are connected by butting together the tip abutting surface 64 and the base abutting surface 65A, which are the abutting surfaces of the apexes 13 and 23 that are adjacent ends, and the base abutting surface 65 and the tip abutting surface 64A, which are the abutting surfaces of the apexes 13 and 23 that are adjacent ends, the arch-shaped precast slabs 11 and 21 are divided in the circumferential direction of the tunnel 31, and the ends of one and the other arch-shaped precast slabs 11 and 21 that are adjacent in the circumferential direction are fitted together by the convex portions 61 and 61A and the concave portions 62 and 62A, and the arch-shaped precast slabs that are continuous with the convex portions 61 and 61A of the apexes 13 and 23 of the one and the other arch-shaped precast slabs 11 and 21 are connected together by the convex portions 61 and 61A and the concave portions 62 and 62A . A through hole 71 is formed in the width direction of the cast slab 11, and a bolt member 80 is inserted into the through hole 71 that is continuous in the width direction of one of the arch-shaped precast slabs 11, 21, and the tops 13, 23 are connected to each other by this bolt member 80. The bolt member 80 is loosely inserted into the through hole 71 and can be moved from the inner surface 11U, 21U side of the arch-shaped precast slabs 11, 21 to the outer surface 11G, 21G side. An upper surface portion 83 is provided on the outer surface 11G, 21G side of the arch-shaped precast slabs 11, 21 as an abutment portion that abuts against the upper surface portion 73 that is on the outer surface 11G, 21G side of the arch-shaped precast slabs 11, 21 of the continuous through hole 71, and a pressing means 85 is provided for pressing the bolt member 80 toward the outer surface 11G, 21G of the arch-shaped precast slabs 11, 21.

With the above configuration, when the pressing means 85 presses the bolt member 80 toward the outer surfaces 11G, 21G of the arched precast slabs 11, 21, the upper surface 83 of the bolt member 80 abuts against the upper surface 73 of the through hole 71 continuing to the convex portions 61 , 61A of both arched precast slabs 11, 21, and the through hole 71 spanning both convex portions 61, 61A is pressed by the bolt member 80, thereby aligning the convex portions 61, 61A along the inner and outer surfaces (thickness direction) of the arched precast slabs. This prevents steps from occurring between the ends of one and the other circumferentially adjacent arched precast slabs 11, 21.

In this way, in this embodiment, in the connection structure of the arch-shaped precast slabs 11, 21 for a tunnel which are installed on the inner surface 33 of the arch-shaped tunnel 31 and connected by butting together the tip abutting surface 64 and the base abutting surface 65A , and the base abutting surface 65 and the tip abutting surface 64A, which are the abutting surfaces of the tops 13, 23 which are adjacent ends, or in the connection structure of the precast slabs for a tunnel which are installed on the inner surface 33 of the arch-shaped tunnel 31 and connected by butting together the end faces 12, 12, 22, 22 which are the abutting surfaces of the adjacent ends, dividing connecting grooves 120, 120 which form a connecting groove 110 spanning between the adjacent precast slabs 11, 21 when the abutting surfaces of the adjacent precast slabs 11, 21 are abutted together are provided in the adjacent precast slabs 11, 21, and the dividing connecting groove 120 The connecting member 111 has a central groove 122 opening on the inner surfaces 11U, 21U of the precast slabs 11, 21, and a spacing groove 123 opening on the inner surfaces 11U, 21U of the precast slabs 11, 21, and is provided with a connecting member 111 that is inserted into the connecting groove 120 to connect adjacent precast slabs 11, 21, and this connecting member 111 integrally has a central connecting portion 112 that is inserted into the central groove 122 of adjacent precast slabs 11, 21 or adjacent precast slabs 11, 11, 21, 21 that are connected across the butt surface, and spacing retaining portions 113, 113 that are provided on both sides of the central connecting portion 112 and inserted into the spacing retaining groove portions 123 of the precast slabs 11, 21 to maintain the spacing between the spacing retaining groove portions 123, 123.

By adopting the above configuration, adjacent precast slabs 11, 21 or adjacent precast slabs 11, 11 or adjacent precast slabs 21, 21 can be connected by inserting a connecting member 111 into the connecting groove 110 spanning between the adjacent precast slabs 11, 21 while the abutting surfaces of the adjacent precast slabs 11, 21 are butted together. This simplifies the connecting work and can be used to connect the ends of adjacent precast slabs 11, 21 in the circumferential direction, as well as to connect adjacent precast slabs 11, 11, 21, 21 in the width direction, making the device highly versatile.

As described above, this embodiment corresponds to claims 1 to 3 and provides the same functions and effects as those of the first embodiment and the first reference example .

The present invention is not limited to this embodiment, and various modifications are possible within the scope of the present invention. For example, while the embodiments and reference examples illustrate two-piece arch-shaped precast slabs, three or more pieces may also be used. Furthermore, a connecting structure 70A may be provided between the stepped surfaces where adjacent arch-shaped precast slabs butt together. Furthermore, the shape of the connecting member can be appropriately selected, such as by making the spacing portion a plate-like shape intersecting the central connecting portion and having a generally H-shaped cross section, and the connecting groove may also be shaped to correspond to the connecting member. Furthermore, while Example 2 illustrates an example in which an arch-shaped precast slab is installed on the inner surface of an existing tunnel, the inner surface of the existing tunnel may be partially or entirely chipped before the installation of the arch-shaped precast slab, or the existing tunnel may be widened before the installation of the arch-shaped precast slab. Furthermore, the shapes of the convex and concave portions at the top may be appropriately selected as long as they fit together.

11 Arch-shaped precast plate (one side)
12 End face (butting surface of end)
13 Top (end )
2 1 Arch-shaped precast plate (left and right)
22 End face (butting surface of end)
23 Top (end )
6 1 Convex portion 61A Convex portion 62 Concave portion 62A Concave portion 64 Tip abutting surface (abutting surface)
64A Tip butt surface (butt surface)
65 Base end butt surface (butt surface)
65A Base end butt surface (butt surface)
70, 70A Connecting structure 73 Upper surface portion (outer surface side of arch-shaped precast plate of through hole)
80 Bolt member 81 Main body 81N Male screw portion 83 Upper surface portion (contact portion, outer surface side of arch-shaped precast plate of main body)
84 Underside (inner surface of arched precast plate of main body)
85 Pressing means 88 Bolt (mounting member)
90 Nut (fixing means)
110: connecting groove 111: connecting member (mounting member)
112 Central connecting portion 113 Spacing portion 120 Dividing connecting groove 121 Embedded member 122 Central groove 123 Spacing groove 128 Butt surface side opening 129 Inner surface side opening 131 Pull-out prevention structure 134 Bolt (fixing means)

Claims (3)

In a connecting structure of arch-shaped precast slabs, the butt surfaces of adjacent ends are butted together to form an arch shape.
and a mounting member attached to the arch-shaped precast plate from the inner surface side of the arch-shaped precast plate to prevent the adjacent ends from shifting .
The arch-shaped precast plates are divided in the circumferential direction, and the ends of one and the other adjacent arch-shaped precast plates in the circumferential direction are fitted together by a convex portion and a concave portion, and through holes are formed in the width direction of the arch-shaped precast plates that are continuous with the convex portions of the ends of the one and the other arch-shaped precast plates, and bolt members are inserted into the through holes that are continuous with the width direction of the one and the other arch-shaped precast plates, and the ends are connected to each other by the bolt members,
A connecting structure for arch-shaped precast slabs, characterized in that the bolt member is loosely inserted into the through hole so as to be able to move from the inner side to the outer side of the arch-shaped precast slab, and the outer side of the arch-shaped precast slab is provided with an abutment portion that abuts against the outer side of the arch-shaped precast slab of the continuous through hole, and a pressing member is provided as the mounting member that presses the bolt member toward the outer side of the arch-shaped precast slab . The bolt member includes a main body provided with the abutment portion and male screw portions provided on both ends of the main body,
The connecting structure of arch-shaped precast slabs as described in claim 1 , characterized in that a recess communicating with the through hole is formed on the inner surface of the end, and a nut is screwed onto the male thread portion protruding into this recess. The bolt member includes a main body provided with the abutment portion and male screw portions provided on both ends of the main body,
a female screw hole is provided between the inner surface of the arch-shaped precast plate and the through hole;
2. The connecting structure of arch-shaped precast slabs according to claim 1 , wherein the pressing member is a bolt that is threaded into the female screw hole and whose tip side abuts against the inner surface of the arch-shaped precast slab of the main body.