Invert block and method for pouring concrete into invert block

Abstract

To provide an invert-block capable of easily carrying out construction to prevent plate swelling in tunnels in a short construction period and at a low cost.SOLUTION: An invert-block 10 that is buried in the pavement at the bottom of a tunnel is constituted of multiple steel elements 10e having a long shape, which is arranged long in a circumferential direction of the tunnel being connected to each other on the long side in the axial direction. These elements 10e are integrated to form a box-shaped hollow structure consisting of an upper plate 10ts, a lower plate 10us and a side plate 10sf. In the connection opening 10ea formed on the longitudinal side of the element 10e, a support member 11 for connecting the internal spaces of both elements 10e and supporting the load from above is placed. In the upper plate 10ts, a concrete pouring hole H1 and a concrete blowing hole H2 are formed, and a connecting pipe P is attached facing upward. The tip of the connecting pipe P is located at the boundary between a roadbed layer and an asphalt layer of a pavement layer L.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a construction technique for preventing ground swelling inside a tunnel. [Background technology]

[0002] Depending on the stress conditions around the tunnel, upward pressure from the bottom of the tunnel may cause the road surface to bulge or deform, resulting in a deterioration in the integrity of the tunnel structure.

[0003] To this end, construction work is carried out to install an inverted arch in the ground at the bottom of the tunnel so that it can withstand the pressure pushing up from the bottom.

[0004] Regarding the technology for constructing inverts in tunnels, for example, the technology described in Patent Document 1 (JP 2020-041381 A) is known. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-041381 Summary of the Invention [Problem to be solved by the invention]

[0006] The construction of inverts in tunnels is generally done using cast-in-place concrete. However, with cast-in-place concrete, the construction period is lengthened due to the time required for setting up formwork for pouring the concrete and curing the concrete. In particular, applying this construction method to tunnels on expressways currently in service would have a significant impact, as it would result in longer lane restrictions.

[0007] Another construction method involves manufacturing a precast invert, transporting it into the tunnel, and then installing it. However, this is not only expensive, but also makes installation difficult, as the construction work is done inside the tunnel, which limits the size of the heavy machinery that can be used. Furthermore, it is difficult to rotate the crane used to lift and install the invert.

[0008] The present invention has been made in light of the above-mentioned technical background, and aims to provide a technology that enables construction work to prevent ground swelling in tunnels to be carried out easily, at low cost, and within a short construction period. [Means for solving the problem]

[0009] In order to solve the above problems, the invert block of the present invention described in claim 1 is an invert block that is installed at the bottom ground of a tunnel and forms an inverted arch shape along the circumferential direction of the tunnel, and is composed of a plurality of steel elements that have a long shape and are connected to each other in the axial direction on their longitudinal sides and arranged long in the circumferential direction of the tunnel, and these elements are integrated to form a box-shaped hollow structure consisting of an upper plate, a lower plate, and side plates, and connection openings formed on the longitudinal sides of the elements are provided with support members that connect the internal spaces of both elements and support loads from above, and the upper plate is formed with concrete pouring holes for pouring concrete into the hollow structure and concrete outlet holes from which the poured concrete is blown out, and connecting pipes connected to the concrete pouring holes and the concrete outlet holes are attached facing upward to the concrete pouring holes and the concrete outlet holes, respectively, and the tips of the connecting pipes are located under the asphalt layer of the pavement layer consisting of a roadbed layer and an asphalt layer laminated on the roadbed layer.

[0010] The invert block of the present invention described in claim 2 is characterized in that, in the invention described in claim 1, the tip of the connecting pipe is located at the boundary between the asphalt layer and the roadbed layer.

[0011] The invert block of the present invention described in claim 3 is characterized in that, in the invention described in claim 1, a lid is removably attached to the tip of the connecting pipe, which is removed when pouring concrete.

[0012] In order to solve the above problem, the method of pouring concrete into an invert block of the present invention described in claim 4 is a method of pouring concrete into an invert block described in any one of claims 1 to 3, characterized in that the entire pavement layer in the area where the invert block is buried is peeled off up to a position where the tip of the connecting pipe is exposed, a pressure pipe for pressure-feeding the concrete is connected to the connecting pipe, and concrete is poured into the invert block through the pressure pipe.

[0013] In order to solve the above problem, the method of pouring concrete into an invert block of the present invention described in claim 5 is a method of pouring concrete into an invert block described in any one of claims 1 to 3, characterized in that the pavement layer in the portion of the connecting pipe connected to the concrete pouring hole and the concrete blow-out hole of the invert block is peeled off to a position where the tip of the connecting pipe is exposed, a pressure pipe for pressure-feeding concrete is connected to the connecting pipe, and concrete is poured into the invert block through the pressure pipe. [Effects of the Invention]

[0014] According to the present invention, an invert block is constructed by simply installing and interconnecting a number of steel elements on-site and then burying it in the pavement of a tunnel. Connecting pipes are attached facing upward to the concrete pouring holes and concrete blow-out holes formed in the top plate of the invert block, with the ends of the connecting pipes positioned below the asphalt layer of the pavement layer, which is made up of a roadbed layer and an asphalt layer laminated on the roadbed layer.

[0015] This makes it easy to pour concrete into the invert block, since the pavement layer only needs to be peeled off up to the position where the tip of the connecting pipe is exposed.

[0016] Therefore, by using the invert blocks of the present invention, construction to prevent ground swelling in tunnels can be carried out easily, at low cost, and in a short construction period. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a plan view showing two invert blocks, one embodiment of the present invention, connected together along the circumferential direction of a tunnel through which vehicles and the like pass and installed on the ground at the bottom of the tunnel. [Figure 2] 2 is a cross-sectional view showing the invert block of FIG. 1 buried in the ground at the bottom of the tunnel and the lower half of the tunnel, viewed from the circumferential direction of the tunnel. [Figure 3] This is a cross-sectional view along the short side of an element other than the tip end in the installation direction and both end portions that constitute an inverter block according to one embodiment of the present invention. [Figure 4] 1 is a cross-sectional view taken along the short side of an element at the rear end in the installation direction of one of both end portions constituting an inverter block according to an embodiment of the present invention. [Figure 5] FIG. 10 is an explanatory diagram showing the short-side side plates of adjacent elements. [Figure 6] (a) is an explanatory diagram showing the relationship between the short-side side plates and the closure plate before adjacent elements are connected, and (b) is an explanatory diagram showing the relationship between the short-side side plates and the closure plate after adjacent elements are connected. [Figure 7] FIG. 2 is a plan view showing the flow direction of concrete poured into the invert block of FIG. 1. [Figure 8] FIG. 8 is a cross-sectional view of FIG. [Figure 9] 1 is an explanatory diagram showing an example of the extent to which temporary paving peels off when concrete is poured into buried invert blocks. FIG. [Figure 10] FIG. 10 is an explanatory diagram showing another example of the extent to which temporary paving peels off when concrete is poured into buried invert blocks. [Figure 11] 2A and 2B are diagrams showing the excavation machine delivery process, which is one step in continuously installing the invert blocks shown in FIG. 1 along the axial direction of the tunnel, where (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from a cross section along the axial direction of the tunnel. [Figure 12] 12A and 12B are diagrams showing the initial excavation process following FIG. 11, where (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. [Figure 13] 13 is a diagram showing the process of bringing in the flooring machine following FIG. 12, where (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. [Figure 14] 14A and 14B are diagrams showing the excavation and bedding process following FIG. 13, in which (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. [Figure 15] 14A and 14B are diagrams showing the unloading and transport machinery installation process, in which (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. [Figure 16] 16A and 16B are diagrams showing the entry and retreat processes of the component transport vehicle following FIG. 15, in which (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from a cross section in the axial direction of the tunnel. [Figure 17] 17A and 17B are diagrams showing the member unloading process following FIG. 16, in which (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from a cross section in the axial direction of the tunnel. [Figure 18] 18A and 18B are diagrams showing the temporary member placement step following FIG. 17, in which (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from a cross section in the axial direction of the tunnel. [Figure 19] 19A and 19B are diagrams showing the member installation process following FIG. 18, where (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. [Figure 20] 20A and 20B are diagrams showing the backfill injection process following FIG. 19, where (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. [Figure 21] 21A and 21B are diagrams showing the backfilling machine delivery process following FIG. 20, where (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. [Figure 22] 22A and 22B are diagrams showing the backfilling process following FIG. 21, in which (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. [Figure 23] 23A and 23B are diagrams showing the rolling compaction process following FIG. 22, in which (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. [Figure 24] 24A and 24B are diagrams showing the process of carrying out heavy machinery and carrying in paving machinery following FIG. 23, in which (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from a cross section in the axial direction of the tunnel. [Figure 25] 25A and 25B are diagrams showing the temporary paving process following FIG. 24, in which (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. [Figure 26] 26A and 26B are diagrams showing the temporary pavement removal and excavation process following FIG. 25, in which (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. [Figure 27] These are drawings showing the temporary pavement removal process, which is one step in pouring concrete into buried invert blocks. (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. [Figure 28] 28A and 28B are diagrams showing the concrete pouring start process following FIG. 27, where (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. [Figure 29] 29 is a diagram showing the concrete pouring execution process following FIG. 28, where (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. [Figure 30] 29A and 29B are diagrams showing the temporary re-paving process following FIG. 29, in which (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings for explaining the embodiment, the same components are generally designated by the same reference numerals, and repeated description thereof will be omitted.

[0019] Figure 1 is a plan view showing two invert blocks, which are one embodiment of the present invention, connected along the circumferential direction of a tunnel through which vehicles and the like pass and installed in the bottom ground of the tunnel; Figure 2 is a cross-sectional view showing the invert block of Figure 1 buried in the bottom ground of the tunnel and the lower half of the tunnel from the circumferential direction of the tunnel; Figure 3 is a cross-sectional view along the short direction of the elements other than the front end in the installation direction and the rear end in the installation direction of one of the two end portions that make up the invert block, which is one embodiment of the present invention; and Figure 4 is a cross-sectional view along the short direction of the element at the rear end in the installation direction of one of the two end portions that make up the invert block, which is one embodiment of the present invention.

[0020] As shown in Figures 1 and 2, the invert blocks 10 of this embodiment are installed and buried in the ground at the bottom of tunnel T, with two blocks connected together in the circumferential direction of tunnel T to form an inverted arch. In this embodiment, the width of one invert block 10 corresponds to the width of one lane. Therefore, the invert blocks 10 of this embodiment are laid in the ground at the bottom of tunnel T, which has two lanes (two lanes on each side for one-way traffic or one lane on each side for bidirectional traffic).

[0021] In the actual installation process, after the invert blocks 10 are installed across the entire length of one lane, the invert blocks 10 are installed across the entire length of the other lane while connecting with the existing invert blocks 10. Depending on the tunnel, three or more invert blocks may be connected in the circumferential direction of the tunnel T to form an inverted arch shape.

[0022] As shown in FIG. 1, the invert block 10 has an elongated shape that is long in the circumferential direction of the tunnel T in which it is installed, and is composed of four steel elements 10e that are connected to each other in the axial direction on their longitudinal sides. These elongated elements 10e are installed long in the circumferential direction of the tunnel T. That is, elements 10e-1 and 10e-4 located at both ends and two elements 10e-2 and 10e-3 located between these elements 10e-1 and 10e-4 are installed long in the circumferential direction of the tunnel T and are connected in parallel to each other in the axial direction of the tunnel T (installation direction). The number of elements 10e does not have to be four; it can be two or more, that is, multiple.

[0023] The inverter block 10 includes an upper plate 10ts, a lower plate 10us, and a side plate 10sf, which are separated into each element 10e. The inverter block 10 is a box-shaped hollow structure consisting of the upper plate 10ts, the lower plate 10us, and the side plate 10sf, which are formed by integrating these elements 10e. The side plate 10sf is made up of a longitudinal side plate 10sf-1, which is a side plate 10sf along the longitudinal direction (a side plate 10sf located in the axial direction of the tunnel), and a transverse side plate 10sf-2, which is a side plate 10sf along the transverse direction (a side plate 10sf located in the circumferential direction of the tunnel). The elements 10e-1 and 10e-4 at both ends include an upper plate 10ts, a lower plate 10us, a longitudinal side plate 10sf-1, and a transverse side plate 10sf-2. The elements 10e-2 and 10e-3 each include an upper plate 10ts, a lower plate 10us, and a short-side side plate 10sf-2, which are welded to each other for each element 10e.

[0024] 2 and 8 (described later) show the invert blocks 10 buried in temporary pavement. Details leading up to the temporary pavement will be described later, but the temporary pavement in this embodiment is formed by forming a roadbed RB on the invert blocks 10, and then forming a pavement road layer L (a layer in which a lower roadbed L1 (crushed stone (crusher run)), an upper roadbed L2 (adjusted-grained crushed stone), a base layer L3 (coarse-grained asphalt concrete), and a surface layer L4 (dense-grained asphalt concrete) are laminated in this order) on the roadbed RB.

[0025] As shown in Figures 3 and 4, ribs 10eb, perpendicular to the upper and lower plates 10ts and 10us, are welded to the inside of connection openings 10ea formed on the longitudinal sides of the elements 10e where the elements 10e are connected, so that they face each other and extend along the longitudinal direction. Support members 11 are attached to these ribs 10eb to support loads from above. As shown in Figure 2, the support members 11 are truss-shaped, so that they are subject to compressive forces due to loads from above but are less susceptible to bending moments. Furthermore, the truss shape creates gaps between the support members 11, allowing the internal spaces of the elements 10e that make up the hollow inverter block 10 to communicate with each other.

[0026] The support member 11 does not need to be truss-shaped, but may be, for example, a vertical lattice-shaped structure that can support loads from above and form spaces that allow the interiors of the elements 10e to communicate with each other (more specifically, spaces large enough to allow concrete poured in a later process to flow from one element 10e to the other element 10e).

[0027] In addition, connecting plates 10ed and 10ef are provided at the locations where the elements 10e are connected to each other, so as to straddle both elements 10e. More specifically, a connecting plate 10ed, which has a slot (through hole, not shown) formed in the axial direction (installation direction) of the tunnel, is attached to the underside of the upper plate 10ts of one of the elements 10e, over the entire length of the upper plate 10ts so as to protrude from the upper plate 10ts. In addition, a connecting plate 10ef, which has a sponge-based sealing material 10ee attached to its upper surface, is attached to the underside of the lower plate 10us of one of the elements 10e, over the entire length of the lower plate 10us so as to protrude from the lower plate 10us. Therefore, the protruding portions of the connecting plates 10ed and 10ef overlap the upper plate 10ts and lower plate 10us of the other element 10e, so that the connecting plates 10ed and 10ef are arranged to straddle both elements 10e. Furthermore, a connecting bolt 10eg is attached to the upper plate 10ts of the other element 10e so as to be able to be tightened from above. The connecting bolt 10eg passes through the aforementioned long hole formed in the connecting plate 10ed and is screwed into the nut 10ec.

[0028] Thus, the connection bolt 10eg passes through a slot formed in the connection plate 10ed and extending in the axial direction (installation direction) of the tunnel. The slot serves as an adjustment margin, allowing the connection bolt 10eg to be threaded onto the nut 10ec without being affected by misalignment of the installation direction when the elements 10e are connected to each other. In other words, because the fastening positions of the connection bolt 10eg and the nut 10ec relative to the slot can be adjusted, when the elements 10e can be installed in close contact with each other depending on the condition of the ground, the connection bolt 10eg and the nut 10ec can be threaded onto each other at the position of the slot when the elements are in close contact with each other. When the elements 10e are not in close contact with each other and are misaligned in the installation direction, the connection bolt 10eg and the nut 10ec can be threaded onto each other at the position of the slot when the elements are misaligned. However, if misalignment of the installation direction when the elements 10e are connected to each other does not need to be considered, the through-hole formed in the connection plate 10ed may be a round hole with a diameter large enough to allow the connection bolt 10eg to pass through, rather than a slot.

[0029] When the elements 10e are installed in close contact with each other, only small gaps are formed between the upper plates 10ts, between the lower plates 10us, and between the short-side side plates 10sf-2 of the elements 10e, but when the elements 10e are installed with a misalignment in the installation direction, gaps equal to the size of the misalignment are formed between the upper plates 10ts, between the lower plates 10us, and between the short-side side plates 10sf-2. These gaps (the small gaps formed when the elements 10e are installed in close contact with each other and the gaps corresponding to the misalignment formed when the elements 10e are installed with a misalignment in the installation direction) are blocked between the upper plates 10ts by connecting plates 10ed, between the lower plates 10us by connecting plates 10ef, and between the short-side side plates 10sf-2 by blocking plates 10eh (described later).

[0030] When the elements 10e are connected to each other, the sealing material 10ee is pressed down from above by the lower plate 10us of the other element 10e and is crushed (for example, crushed to 1 mm or less), thereby forming a seal.

[0031] Therefore, by screwing the connecting bolt 10eg into the nut 10ec, two adjacent elements 10e are connected to each other via the upper connecting plate 10ed, and the sealing material 10ee of the lower connecting plate 10ef is crushed and sealed, making it difficult for soil and sand to enter the hollow inverter block 10 from the outside.

[0032] The sealing material 10ee may also be provided over the entire length of the upper surface of the connecting plate 10ed provided on the top plate 10ts.

[0033] Support bolts 15 are attached to the lower plate 10us of the element 10e, protruding downward. When the element 10e is installed on the ground, the support bolts 15 are provided at both longitudinal ends of the element 10e, and serve to adjust the height of the element 10e by sandwiching a base 16 between the lower end of the support bolt 15 and the ground.

[0034] Additionally, nuts 17 that screw onto the support bolts 15 are fixed by welding to the positions of the holes through which the support bolts 15 pass in the lower plate 10us of the element 10e.

[0035] Element 10e-1 (starting element), which is located at the end of inverter block 10 and is installed first when inverter block 10 is formed, is provided with two support bolts 15 at each of its longitudinal ends, for a total of four support bolts 15, while the other elements 10e-2, 10e-3, and 10e-4 are provided with one support bolt 15 at each of their longitudinal ends, for a total of two support bolts 15. This is because element 10e-1, which is installed first, needs to be stabilized with four support bolts 15, whereas elements 10e-2, 10e-3, and 10e-4 are connected successively to existing elements 10e-1, 10e-2, and 10e-3, respectively, and therefore can be stabilized with two support bolts 15. However, the number of support bolts 15 is not limited to four or two as described above, and may be any number greater than or equal to the number shown in this embodiment. In the illustrated example, the support bolts 15 provided on elements 10e-2, 10e-3, and 10e-4 are positioned on the element installation direction side at both ends in the longitudinal direction, but they do not have to be positioned in this way, and may be, for example, on the opposite side of the element installation direction.

[0036] As shown in Figure 3, the support bolt 15 on the side opposite the element installation direction of the first-installed element 10e-1 (the support bolt 15 shown on the left side of element 10e-1 in Figure 3) is located deep inside, making it difficult for an operator to reach through the connection opening 10ea. Therefore, the support bolt 15 in this position is housed in a bolt hole H4 that passes through the element 10e in the vertical direction, and has a wrench hole (such as a hexagonal wrench hole) formed in its head. A long wrench (such as a hexagonal wrench) is inserted from the top of bolt hole H4 to turn the support bolt 15 and adjust the height of element 10e-1.

[0037] Also, as shown in Figure 3, the support bolt 15 located on the element installation direction side of element 10e-1 (support bolt 15 shown to the right of element 10e-1 in Figure 3), and the support bolts 15 of elements 10e-2 and 10e-3 located between element 10e-1 and element 10e-4 (the element located at the end of the invert block 10 and installed last when forming the invert block 10: the terminal element) (support bolt 15 shown for elements 10e-2 and 10e-3 in Figure 3) are located in positions that can be reached by an operator inserting their hand through the connection opening 10ea, and are therefore located in positions that can be rotated from the connection opening 10ea.

[0038] 4, the support bolt 15 of the element 10e-4 is provided in a position where it can be rotated from the gap between the element 10e-4 and the ground, because when the element 10e-4 is connected to the adjacent element 10e-3, workers cannot reach through the connection opening 10ea. In this case, as shown in the figure, the support bolt 15 is screwed upward from below the lower plate 10us so that the head 15a of the support bolt 15 (i.e., the part that turns the support bolt) is between the element 10e-4 and the ground.

[0039] Here, the structure of the side plate 10sf of the inverter block 10 will be explained using Figures 5 and 6. Figure 5 is an explanatory diagram showing the short-side side plate of adjacent elements, and Figure 6 is an explanatory diagram showing the relationship between the short-side side plate of adjacent elements and the blocking plate, where (a) shows the adjacent elements before they are connected, and (b) shows the adjacent elements after they are connected.

[0040] The inverter block 10 has side plates 10sf (longitudinal side plates 10sf-1 and lateral side plates 10sf-2) for each element 10e. As described above, a gap is formed between the lateral side plates 10sf-2 of adjacent elements 10e according to the fastening positions of the connecting bolts 10eg and nuts 10ec relative to the elongated holes formed in the connecting plates 10ed (see FIG. 6(a)).

[0041] If this gap is left as it is, soil and sand will get into the hollow invert block 10, and when concrete is poured in a later process, the concrete will leak out through the gap. Therefore, as shown in Figures 5 and 6(a), a blocking plate 10eh is provided to block the gap that is formed between the two short-side side plates 10sf-2 when the elements 10e (here, elements 10e-1 and 10e-2) are connected to each other.

[0042] This closure plate 10eh is welded to the outer surface of the side end of the short-side plate 10sf-2 of one element 10e (element 10e-2 in the illustrated case), protruding in the tunnel axis direction so that a portion of it overlaps with the short-side plate 10sf of the adjacent element (element 10e-1 in the illustrated case). As a result, the closure plate 10eh closes the gap that is formed when the elements 10e (here, elements 10e-1 and 10e-2) are connected to each other. Note that once the elements 10e are connected to each other, it is desirable to either weld the gap between the other element 10e (here, element 10e-1) and the closure plate 10eh or seal it with a pre-installed sealant.

[0043] 1, a plurality of (here, two) H-shaped steel piles 12 are erected. These piles 12 serve both as guardrail supports for dividing two lanes and as support piles for horizontal sheet piles used during ground excavation (horizontal sheet piles used as retaining walls when excavating the ground to install invert blocks 10). Therefore, recesses are formed in elements 10e constituting invert blocks 10 to avoid interference with the piles 12.

[0044] As shown in FIG. 1 , elements 10e-1 and 10e-4, located at both ends of the invert block 10 in the installation direction (tunnel axis direction), have connecting holes 13 with nuts fixed inside formed in the upper plate 10ts. These connecting holes 13 are used to connect adjacent invert blocks 10 via connecting plates (not shown). That is, the connecting plates are fixed to the invert blocks 10 by threading bolts through through holes formed in the connecting plates and into nuts in the connecting holes 13. The same connecting plates are then bolted to adjacent invert blocks 10, thereby connecting the adjacent invert blocks 10 via the connecting plates. Note that the number of connecting holes 13 may be one, rather than multiple as in this embodiment.

[0045] As shown in Figure 2, each element 10e has two longitudinal positions on the upper plate 10ts thereof, each of which has a hanging fitting 14 that can engage with a hook attached to the end of a wire, so that the element 10e can be hung by the wire of a crane (such as a crawler crane) and installed on the ground at the bottom of the tunnel T.

[0046] 1, 3, and 4, each element 10e is provided with a grout injection hole H3 for injecting grout between the element 10e and the ground when the element 10e is installed in the ground at the bottom of the tunnel to fill any gaps between the element 10e and the ground. This grout injection hole H3 is cylindrical and penetrates the element 10e in the vertical direction (i.e., it is isolated from the hollow internal space). Therefore, grout injected from the upper grout injection hole H3 passes through the cylindrical grout injection hole H3 and fills the gap between the element 10e and the ground.

[0047] As shown in Figure 1, the upper plate 10ts of the invert block 10 is formed with a concrete pouring hole H1 for pouring concrete into the hollow interior in a later process, and a concrete blowout hole H2 from which the poured concrete is blown out.

[0048] As shown in the figure, the concrete pouring hole H1 is formed in one location at a low position (near the center on the side opposite the side wall of the tunnel T to be installed) of the upper plate 10ts of the invert block 10 when it is installed in the bottom ground of the tunnel T, and the concrete blowout holes H2 are formed in two locations at high positions (corners on the side wall side of the tunnel T to be installed) of the upper plate 10ts of the invert block 10 when it is installed in the bottom ground of the tunnel T. Note that the number and positions of the concrete pouring holes H1 and the concrete blowout holes H2 are not limited to the case shown in this embodiment. However, it is desirable that the concrete blowout holes H2 be formed in corners on the side wall side of the tunnel T to be installed so that internal air can be smoothly discharged during concrete pouring.

[0049] Here, in the invert block 10 of this embodiment, which is composed of four (an even number) elements 10e, the concrete pouring hole H1 is formed in element 10e-2 of the two elements 10e (10e-2, 10e-3) located in the center. However, if there is an even number of elements 10e and these elements 10e are installed with a gradient in the axial direction of the tunnel T, it is desirable to form the concrete pouring hole H1 in the element 10e located at the lower position of the two elements 10e located in the center. Note that, in an invert block 10 composed of an odd number of elements 10e, the concrete pouring hole H1 is formed in the element 10e located in the center.

[0050] In addition, the concrete pouring holes H1 may be formed in two or more locations (i.e., they must be formed in at least one location on the side opposite the side wall of the tunnel T to be installed), and the concrete blow-out holes H2 may be formed in three or more locations (i.e., they must be formed in at least two locations on both sides of the side wall of the tunnel T to be installed).

[0051] Furthermore, in a later process, concrete is poured while the invert block 10 is buried in the ground at the bottom of the tunnel T, and therefore, as shown in Figure 2, connecting pipes P are attached facing upward to the concrete pouring hole H1 and the concrete blowout hole H2. This makes it possible to pour concrete into the invert block 10 and blow concrete out of the invert block 10 simply by exposing the connecting pipe P from the ground in which the invert block 10 is buried. A detachable cover (not shown) is attached to the tip of the connecting pipe P to prevent soil and sand from getting inside the invert block 10 when not pouring concrete.

[0052] In this embodiment, the connecting pipe P is a steel pipe with a diameter of about 6 inches, which is the same diameter as the pressure pipe (a pipe attached to a pump truck to pressure-feed concrete) to which it is connected via a joint when pouring concrete in a subsequent process. However, the diameter of the connecting pipe P is determined according to the diameters of the concrete pouring hole H1 and the concrete blowout hole H2 and the diameter of the pressure pipe, and is not limited to 6 inches as in this embodiment.

[0053] Here, the flow of concrete when pouring concrete into the invert blocks 10 in a later process (a process after the invert blocks 10 are installed) will be explained using Figures 7 and 8. Figure 7 is a plan view showing the flow direction of concrete poured into the invert blocks of Figure 1, and Figure 8 is a cross-sectional view of Figure 7.

[0054] As mentioned above, the concrete pouring hole H1 is formed at a low position on the upper plate 10ts of the invert block 10 when it is installed on the bottom ground of the tunnel T, and the concrete blowout hole H2 is formed at a high position on the upper plate 10ts of the invert block 10 when it is installed on the bottom ground of the tunnel T.

[0055] 7 and 8, when concrete C is poured into the invert block 10 through the concrete pouring hole H1 formed in element 10e-2 (more specifically, the connecting pipe P attached to the concrete pouring hole H1), the concrete C flows from directly below the concrete pouring hole H1 through the gaps in the support member 11 into the other elements 10e-1, 10e-3, and 10e-4, and fills the hollow structure by forcing out the air inside through the concrete blowout hole H2. When the concrete C is blown out from the concrete blowout hole H2 formed at the highest position (more specifically, the connecting pipe P attached to the concrete blowout hole H2), it is assumed that the entire interior of the invert block 10 has been filled with concrete C.

[0056] As shown in FIG. 8, the tips of the connecting pipe P attached to the concrete pouring hole H1 and the connecting pipe P attached to the concrete blowout hole H2 are located at the boundary between the base layer L3 and upper subgrade L2 that make up the pavement road layer L (i.e., the boundary between the subgrade layer (lower subgrade L1, upper subgrade L2) and the asphalt layer (base layer L3, surface layer L4)). Therefore, when pouring concrete C into the buried invert block 10 in a later process, the two layers of the surface layer L4 and the base layer L3 (i.e., the asphalt layers) are peeled off to expose the tip of the connecting pipe P, and the lid is removed. The connecting pipe P attached to the concrete pouring hole H1 can then be connected to a pressure pipe from a pump truck via a joint (not shown).

[0057] In this way, by attaching the connecting pipe P to the concrete pouring hole H1 and the concrete blow-out hole H2, when pouring concrete into the invert block 10, it is sufficient to peel off the asphalt layers, base layer L3 and surface layer L4, to expose the tip of the connecting pipe P, and there is no need to remove the roadbed RB to expose the invert block 10 itself, making it easier to pour the concrete.

[0058] In this embodiment, the pavement road layer L is formed by sequentially stacking the lower roadbed L1, upper roadbed L2, base layer L3, and surface layer L4, and the tip of the connecting pipe P is located at the boundary between the base layer L3 and the upper roadbed L2. However, the configuration of the pavement road layer L and the tip position of the connecting pipe P are not limited to this. In other words, the pavement road layer L is formed of a roadbed layer and an asphalt layer stacked on the roadbed layer, and the tip position of the connecting pipe P may be located at the boundary between the roadbed layer and the asphalt layer or below the boundary (i.e., below the asphalt layer). If the tip position of the connecting pipe P is below the boundary between the roadbed layer and the asphalt layer, when pouring concrete C into the invert block 10, the two layers of the surface layer L4 and base layer L3 (i.e., the asphalt layers) and a portion of the roadbed layer are peeled off to expose the tip of the connecting pipe P.

[0059] However, as in this embodiment, if the tip of the connecting pipe P is located at the boundary between the roadbed layer and the asphalt layer (here, the boundary between the upper roadbed L2 and the base layer L3), the tip of the connecting pipe P can be easily exposed by simply peeling off the asphalt layer (here, the base layer L3 and the surface layer L4) without having to peel off the roadbed layer (here, the lower roadbed L1 and the upper roadbed L2).

[0060] The range of temporary pavement to be removed may be the entire area where the invert blocks 10 into which concrete will be poured are buried, as shown in Figure 9, or only the area around the connecting pipe P, as shown in Figure 10. However, when constructing an expressway, it is desirable to remove the temporary pavement from the entire area where the invert blocks 10 into which concrete will be poured are buried. Furthermore, when constructing an ordinary road, it is sufficient to only remove the temporary pavement around the connecting pipe P.

[0061] As explained above, the invert block 10 of this embodiment, which is buried in the pavement at the bottom of a tunnel, is composed of four elongated steel elements 10e connected to each other in the axial direction on their longitudinal sides, and has a hollow structure with an upper plate 10ts, a lower plate 10us, and a side plate 10sf. Inside the connection openings 10ea of ​​the elements 10e formed on the longitudinal sides where the elements 10e are connected, support members 11 are installed to connect the internal spaces of both elements 10e and to support loads from above.

[0062] Furthermore, the upper plate 10ts is formed with a concrete pouring hole H1 for pouring concrete into its hollow interior, and a concrete blowout hole H2 from which the poured concrete is blown out, and a connecting pipe P is attached to the concrete pouring hole H1 and the concrete blowout hole H2 facing upward. The tip of the connecting pipe P is located at the boundary between the base layer L3 and upper subgrade L2 that make up the pavement.

[0063] As a result, when pouring concrete into the invert block 10, it is only necessary to peel off the base layer L3 and surface layer L4 to expose the tip of the connecting pipe P, and there is no need to remove down to the roadbed RB to expose the invert block 10 itself, making it possible to pour the concrete easily.

[0064] Therefore, by using the invert block 10 of this embodiment, construction to prevent ground swelling in tunnels can be carried out easily, at low cost, and in a short construction period.

[0065] Next, the process of installing the invert block 10 described above in the tunnel T will be described with reference to Figs. 11 to 26. Here, as an example, a case will be described in which the invert block 10 is installed under one lane of a tunnel T that is one-way with two lanes on each side.

[0066] FIG. 11 is an explanatory diagram showing the excavation machine delivery process, which is one process for continuously installing the invert blocks of FIG. 1 along the axial direction of the tunnel; FIG. 12 is an explanatory diagram showing the initial excavation process following FIG. 11; FIG. 13 is an explanatory diagram showing the bedding machine delivery process following FIG. 12; FIG. 14 is an explanatory diagram showing the excavation and bedding process following FIG. 13; FIG. 15 is an explanatory diagram showing the unloading and transport machine delivery process following FIG. 14; FIG. 16 is an explanatory diagram showing the entry and retreat process of the component transport vehicle following FIG. 15; 8 is an explanatory diagram showing the temporary placement process of components following Fig. 17, Fig. 19 is an explanatory diagram showing the component installation process following Fig. 18, Fig. 20 is an explanatory diagram showing the backfill injection process following Fig. 19, Fig. 21 is an explanatory diagram showing the backfill machine delivery process following Fig. 20, Fig. 22 is an explanatory diagram showing the backfill process following Fig. 21, Fig. 23 is an explanatory diagram showing the compaction process following Fig. 22, Fig. 24 is an explanatory diagram showing the heavy equipment removal and paving machine delivery process following Fig. 23, Fig. 25 is an explanatory diagram showing the temporary paving process following Fig. 24, Fig. 26 is an explanatory diagram showing the temporary paving removal and excavation process following Fig. 25. In these drawings, (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel.

[0067] First, as shown in Figure 11, one lane is designated as a restricted zone where general vehicles are restricted from passing in order to lay invert blocks 10, and the other lane is designated as a traffic lane where general vehicles can pass. Then, a trailer 21 carrying a backhoe (e.g., a 0.45 class backhoe) 20 as an excavation machine is driven from the traffic lane into the restricted zone, where the backhoe 20 is unloaded and carried into the restricted zone (excavation machine carrying process). The trailer 21 exits the tunnel from the end of the restricted zone (the end opposite the entrance).

[0068] Here, in this embodiment, a backhoe is used as the heavy machine for excavating the ground, but a hydraulic excavator other than a backhoe may also be used.

[0069] Next, as shown in Figure 12, a dump truck (for example, a 10-ton dump truck) 22 is driven from the traffic lane into the restricted zone and backed up to a loading position for the excavated earth and sand. Then, a backhoe 20 is used to excavate earth and sand from the restricted zone and load it onto the dump truck 22 (initial excavation process). Once the dump truck 22 has loaded earth and sand up to the specified weight, it exits the tunnel from the end of the restricted zone.

[0070] Next, as shown in Figure 13, a trailer 21 carrying a small backhoe 23 (for example, a 0.1 class backhoe) as a laying machine is driven from the traffic lane into the restricted zone, and the backhoe 23 is lowered between the backhoe 20 and the excavated area S (the area excavated by the backhoe 20) (laying machine delivery process). Note that because the backhoe 20 is ahead of the trailer 21 and the trailer 21 cannot proceed through the restricted zone, safety is ensured by a speed limiter (not shown) that has been introduced into the traffic lane, which limits the speed of following general vehicles to the speed limiter, and the trailer 21 exits the restricted zone into the traffic lane when it is ahead of the speed limiter, and exits the tunnel.

[0071] Next, as shown in Figure 14, a backhoe 20 excavates the soil in the restriction zone and loads it onto a dump truck 22, and a small backhoe 23 flattens the bedding surface of the excavated area S (excavation and bedding process). Once the dump truck 22 has loaded soil up to the specified weight, it exits the tunnel from the end of the restriction zone.

[0072] Next, as shown in Figure 15, a trailer (not shown) carrying a crawler crane 24 (e.g., a 4.9-ton crawler crane) as an unloading and transporting machine is driven from the traffic lane into the restricted zone, and the crawler crane 24 is lowered just before the excavated area S (on the opposite side of the direction of excavation and bedding of the excavated area S) (unloading and transporting machine delivery process). Note that because the excavated area S is ahead and the trailer cannot proceed through the restricted zone, a speed limiter (not shown) is introduced into the traffic lane to limit the speed of following general vehicles, ensuring safety. Once the trailer is ahead of the speed limiter, it exits the restricted zone into the traffic lane and exits the tunnel. During this time, the excavation and bedding process (see Figure 14) continues.

[0073] Next, as shown in Figure 16, a dump truck (for example, a 4-ton dump truck) 25, which serves as a component transport vehicle and which is loaded with the element 10e, is driven from the traffic lane into the area between the excavated area S of the restricted zone and the crawler crane 24, and then driven back up to the vicinity of the crawler crane 24 (component transport vehicle entry and backing up process). During this time, the excavation and bed-laying process (see Figure 14) continues.

[0074] Next, as shown in Fig. 17, the elements 10e loaded onto the dump truck 25 are unloaded by the crawler crane 24 (member unloading process). During this time, the excavation and bed-laying process (see Fig. 14) continues.

[0075] Next, as shown in Figure 18, the unloaded element 10e is temporarily placed in front of the excavated area S (temporary member placement process). Note that the excavation and bedding process (see Figure 14) continues during this time. Also, since the dump truck 25 that has loaded the element 10e cannot proceed through the restricted zone due to the excavated area S ahead, safety is ensured by a speed limiter (not shown) that has been introduced into the traffic lane restricting the speed of following general vehicles to the speed limiter, and the dump truck exits the restricted zone into the traffic lane when it is ahead of the speed limiter, and exits the tunnel. Note that the excavation and bedding process (see Figure 14) continues during this time.

[0076] Next, as shown in Figure 19, the unloaded elements 10e are installed in the excavated area S by the crawler crane 24 (member installation process). That is, as shown in the figure, the longitudinal direction of the elements 10e is oriented in the circumferential direction of the tunnel, and the elements 10e are installed by the crawler crane 24 along the axial direction (installation direction) of the tunnel T. Then, the expansion and contraction amounts of the support bolts 15 are adjusted to align the heights of the four elements 10e, and the connecting bolts 10eg are screwed into the nuts 10ec to connect the elements 10e together, thereby forming an invert block 10 that integrates these elements 10e (see Figures 3 and 4).

[0077] As mentioned above, in this embodiment, four elements 10e are installed to form one invert block 10. The axial length of the tunnel T formed by these elements 10e is, for example, 3 m. However, this length varies depending on the number of elements 10e to be installed and the width of the elements 10e, and is not limited to 3 m. During this time, the excavation and bed-laying process (see FIG. 14) continues.

[0078] Here, the work of installing (mounting) the elements 10e, the work of aligning the heights of the installed elements 10e, and the work of connecting the elements 10e with aligned heights to form the inverter block 10 may be performed for each element 10e, or may be performed all at once for all the elements 10e that make up the inverter block 10.

[0079] Specifically, the inverter block 10 may be formed by repeatedly placing the elements 10e one by one, aligning the heights, and connecting them. Alternatively, the elements 10e that make up the inverter block 10 may be placed one by one, aligning the heights, and connecting all of the elements 10e together to form the inverter block. Alternatively, all of the elements 10e that make up the inverter block 10 may be placed together, aligning the heights of all of the elements 10e that make up the inverter block 10 together, and connecting all of the elements 10e that make up the inverter block 10 together to form the inverter block.

[0080] Next, once one invert block 10 has been formed, grout (backfilling material) G is injected between the invert block 10 and the installation ground as shown in Figure 20 (backfilling material injection process). In this embodiment, a high-early-strength type grout G is used, which has excellent early strength development properties and reaches high strength in a short period of time. However, grout other than the high-early-strength type may also be used.

[0081] In this process, concrete panels or other anti-flow walls W are erected on the sides of the invert blocks 10 (specifically, on the sides of the elements 10e-4 at the tunnel axial end and on the sides of the invert blocks 10 facing the tunnel sidewall) to prevent the injected grout G from flowing out. Sandbags D are placed on the outside of the anti-flow walls W to prevent them from collapsing. Then, a dump truck (e.g., a 2-ton dump truck) 26 carrying grout G and grout pumping equipment GE, such as a pump for pumping the grout G, enters the restricted zone, and grout G is injected between the bottom of the invert blocks 10 and the installation ground through grout injection holes H3 (see FIGS. 1, 3, and 4) provided in each element 10e. In this embodiment, the grout is injected after one day's worth of construction. However, the timing of the grout injection is not limited to one day's worth of construction and may be other injection timings. Furthermore, the member for preventing the spill prevention wall W from falling over may be other than the sandbag D.

[0082] Between the backfilling material injection process and the backfilling process described later, connecting pipes P (see FIGS. 2 and 8) are attached to the concrete pouring holes H1 and the concrete blowout holes H2 formed in each element 10e. A cap (not shown) is placed on the end of the connecting pipe P to prevent soil and sand from getting inside. However, the connecting pipe P is not shown in FIGS. 20 to 26. The excavation and bedding process (see FIG. 14) continues during this process.

[0083] Next, once the grout has hardened, the flow prevention wall W and sandbags D are removed, and as shown in Figure 21, a backhoe (e.g., a 0.45 class backhoe) 27 for backfilling with subgrade material and a compaction roller 28 for compacting the backfilled subgrade material are brought into the restriction zone (backfilling machine bringing-in process). During this time, the excavation and bedding process (see Figure 14) continues.

[0084] Next, as shown in FIG. 22, a dump truck (e.g., a 4-ton dump truck) 29 loaded with backfill soil (subgrade material) is driven from the traffic lane into the restricted zone and introduced between a backhoe 27 and a compaction roller 28. The backhoe 27 then transfers the subgrade material from the dump truck 29 onto the invert blocks 10 (i.e., the interconnected and integrated elements 10e) to backfill the area (backfilling process). In FIG. 22 and the following FIG. 23, the symbol ES indicates the subgrade material, which is backfill soil. After the subgrade material is transferred and the dump truck 29 is emptied, it moves from the restricted zone to the traffic lane and exits the tunnel. During this process, the excavation and bed-laying process (see FIG. 14) continues. Furthermore, in the illustrated example, the number of elements 10e required to form one invert block 10 is installed before backfilling. However, it is of course possible to install the number of elements 10e required to form multiple invert blocks 10 before backfilling.

[0085] Next, as shown in Figure 23, the roadbed material ES is compacted with a compaction roller 28 to form the roadbed RB (Figure 24) (compaction process). In this compaction process, the roadbed material ES is compacted, so the surface of the formed roadbed RB is lower than the surrounding road surface (see Figure 24). Note that the excavation and bedding process (see Figure 14) continues during this process.

[0086] For example, if Monday through Friday are considered one work unit so that the restricted zone is also open to general vehicles on Saturdays and Sundays, the above-described excavation and bed-laying process (Fig. 14) through compaction process (Fig. 23) are repeated sequentially from Monday to Thursday to form a continuous invert block structure in which invert blocks 10 are installed continuously along the axial direction of the tunnel, and these are then buried in the roadbed RB where the roadbed material ES has been compacted. Here, adjacent invert blocks 10 are connected by threading bolts through through-holes formed in the connecting plates with nuts in connecting holes 13, as described above, to ensure that they are all the same height.

[0087] It should be noted that the method for carrying out one task unit and the steps within one task unit are not limited to those described in this embodiment, and can of course be freely set.

[0088] After the final compaction process (Fig. 23) on Thursday is completed, all excavation machinery other than the compaction roller 28 is removed from the tunnel, and paving machinery such as the asphalt finisher 33 is brought in (excavation machinery removal and paving machinery introduction processes), as shown in Fig. 24. Depending on the progress of the work, as shown in Fig. 24, the excavated area S that has been backfilled may include areas where the invert blocks 10 have been buried and areas where they have not been buried.

[0089] Next (on Friday in this embodiment), temporary paving is applied to the area S excavated from Monday to Thursday, as shown in FIG. 25 (temporary paving process). As mentioned above, this is to minimize the impact on general vehicles of one-way traffic for construction work by opening the regulated zone to general vehicles on Saturdays and Sundays. In this embodiment, temporary paving is performed by forming a pavement road layer L, which is made by sequentially layering a lower roadbed L1, an upper roadbed L2, a base layer L3, and a surface layer L4 on the roadbed RB. After the temporary paving is completed, the paving equipment that was brought in is removed, and the regulated zone is opened.

[0090] Next (in this embodiment, on the following Monday), as shown in Figure 26, the temporary paving in the excavated area S where the invert blocks 10 are not buried is removed with a backhoe 20 (temporary paving removal process). Then, the above-mentioned excavation and bedding process (Figure 14) to the compaction process (Figure 23) are repeated in order from Monday to Thursday. Furthermore, after the final compaction process (Figure 23) on Thursday is completed, the excavation heavy equipment removal and paving heavy equipment delivery process (Figure 24) is carried out, and on Friday the temporary paving process (Figure 25) is carried out.

[0091] Once a plurality of continuous invert blocks 10 (continuous invert block structure) have been buried in part or all of one lane of tunnel T as described above, the next process is to pour concrete into the buried invert blocks 10. Next, the process of pouring concrete into the invert blocks 10 will be described with reference to Figures 27 to 30.

[0092] Figure 27 is an explanatory diagram showing the temporary pavement removal process, which is one step in pouring concrete into buried invert blocks, Figure 28 is an explanatory diagram showing the concrete pouring start process following Figure 27, Figure 29 is an explanatory diagram showing the concrete pouring execution process following Figure 28, and Figure 30 is an explanatory diagram showing the temporary pavement re-processing following Figure 29. In these drawings, (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel.

[0093] First, as shown in Figure 27, a backhoe (e.g., a 0.45-class backhoe) 30 serving as an excavation machine is used to remove the temporary pavement, exposing the tip of the connecting pipe P attached to the concrete pouring hole H1 and the concrete blowout hole H2 (temporary pavement removal process). As described above, in this embodiment, the tip of the connecting pipe P is located at the boundary between the base layer L3 and the upper roadbed L2 that make up the pavement road layer L. Therefore, the two layers (asphalt layers) of the surface layer L4 and the base layer L3 are removed, but the two layers (roadbed layers) of the upper roadbed L2 and the lower roadbed L1 are not removed. However, in Figures 27 to 29, the surface layer L4, base layer L3, upper roadbed L2, and lower roadbed L1 are not shown.

[0094] As mentioned above, the area of ​​the temporary paving to be removed to expose the tip of the connecting pipe P may be limited to the area around the connecting pipe P, or it may be the entire area where the invert block 10 into which concrete will be poured is buried, but here we will focus on the latter area of ​​removal.

[0095] In this embodiment, when pouring concrete into existing invert blocks 10, each of the steps from the excavation and flooring step (FIG. 14) to the compaction step (FIG. 23) is carried out in parallel in different areas, as shown in FIG. 27 and the following FIGS. 28 and 29. In this way, pouring concrete into the existing buried invert blocks 10 and installing and burying the invert blocks 10 in the unexcavated areas are carried out in parallel in different areas, making it possible to complete the series of work in a shorter construction period.

[0096] After the tip of the connecting pipe P is exposed during the temporary pavement removal process shown in FIG. 27, a mixer truck 31 transporting ready-mixed concrete and a concrete pump truck 32, which is docked with the mixer truck 31 to receive the ready-mixed concrete in its hopper and pumps the ready-mixed concrete through a pressure pipe 32a using an equipped pump (not shown), are introduced into the restricted area as shown in FIG. 28. The caps on the tips of the connecting pipes P attached to the concrete pouring hole H1 and the concrete blowout hole H2 are removed, and a joint is used to connect the pressure pipe 32a of the concrete pump truck 32 to the connecting pipe P attached to the concrete pouring hole H1 (here, the connecting pipe P of the invert block 10 buried closest to the concrete pump truck 32). Then, pouring of concrete into the invert block 10 begins (concrete pouring start process). After the mixer truck 31 has poured the required amount of ready-mixed concrete into the hopper of the concrete pump truck 32, it enters the traffic lane and exits the tunnel.

[0097] In this embodiment, high-fluidity concrete is used for the concrete to be poured. High-fluidity concrete uses less water than regular concrete and has high fluidity, so it can be reliably filled into every corner of the invert block 10 without the need for vibration or compaction. However, it goes without saying that concrete other than high-fluidity concrete, such as ordinary concrete or fluidized concrete, can also be used for the concrete to be poured.

[0098] Once concrete pouring has begun in the concrete pouring start process shown in Figure 28, the pressure pipe 32a of the concrete pump truck 32 is connected sequentially to the connecting pipes P attached to the concrete pouring holes H1 of each buried invert block 10, and the concrete is pressure-fed and poured.

[0099] When pouring concrete into each invert block 10, of the two connecting pipes P attached to the concrete blowout holes H2, the one from which concrete is blown out first is capped as soon as it starts to blow out to prevent leakage. The other connecting pipe P attached to the concrete blowout hole H2 is also capped as soon as concrete starts to blow out. Then, once the two connecting pipes P attached to the concrete blowout hole H2 are capped, the connecting pipe P attached to the concrete pouring hole H1 is also capped.

[0100] In this way, as shown in Figure 29, concrete is poured into the buried invert blocks 10 (concrete pouring execution process) to create the invert. Here, as described above, the installation and burying of the invert blocks 10 and the pouring of concrete into the existing buried invert blocks 10 are carried out in parallel. However, because the invert is created by pouring concrete into the invert blocks 10, in the final stage, these processes are not carried out in parallel, and only concrete is poured into the existing invert blocks 10.

[0101] Once concrete has been poured into all of the buried invert blocks 10 to create the invert, the peeled base layer L3 and surface layer L4 are layered in sequence on top of the upper roadbed L2, as shown in Figure 30, to perform re-temporary paving (re-temporary paving process). Here, if the temporary paving has only been removed from the area surrounding the connecting pipe P, the re-temporary paving may involve filling the peeled area with, for example, coarse-grained asphalt concrete, instead of layering the base layer L3 and surface layer L4 in sequence. Note that the connecting pipe P is not shown in Figure 30. Temporary paving is also performed on the excavated area S that was previously excavated to install the invert blocks 10 (see Figure 25).

[0102] In this way, concrete is poured into the invert blocks 10 buried in one lane of tunnel T, and an invert is created. After the invert is created by burying the invert blocks 10 (FIGS. 11 to 26) and pouring concrete (FIGS. 27 to 30) throughout one lane of tunnel T, the invert is then created for the other lane by similarly burying the invert blocks 10 and pouring concrete. Thus, a continuous invert block structure, consisting of multiple invert blocks 10 connected in series along the axial direction of the tunnel, is installed in multiple rows (two rows in this embodiment) along the axial direction of the tunnel. Two invert blocks 10 (two inverts) facing each other in the circumferential direction of tunnel T form an inverted arch shape along the circumferential direction of tunnel T (see FIG. 2). When the invert blocks 10 are installed in the other lane, they are fastened with bolts to the opposing invert blocks 10 in the one lane for which concrete has already been poured.

[0103] Finally, the entire area of ​​the tunnel T that has been temporarily repaved is stripped away, and the final finishing process of full paving (paving at the original thickness) is carried out, completing the series of processes.

[0104] The invention made by the inventor has been specifically described above based on the embodiments, but the embodiments disclosed in this specification are illustrative in all respects and are not limited to the disclosed technology. In other words, the technical scope of the present invention should not be interpreted restrictively based on the description of the above embodiments, but should be interpreted solely in accordance with the claims, and includes technologies equivalent to the technologies described in the claims and all modifications that do not deviate from the gist of the claims. [Industrial Applicability]

[0105] In the above explanation, the invert block of the present invention is described as being installed in a tunnel that is currently in use, but it can also be installed in a newly constructed tunnel. [Explanation of symbols]

[0106] 10 Inverter block 10e Element 10ea Connection opening 10eb Rib 10ec Nut 10ed connection plate 10ee sealing material 10ef connection board 10eg connection bolt 10eh occlusion plate 10sf side plate 10sf-1 Longitudinal side panel 10sf-2 Short side side plate 10ts upper plate 10us lower board 11 Support member 12 stakes 13 Connection hole 14 Hanging hardware 15 Support bolt 16 Pedestal 17 Nut 20 Backhoe 21 Trailer 22 Dump Truck 23 Backhoe 24 Crawler crane 25 Dump Truck 26 Dump Truck 27 Backhoe 28 Compaction roller 29 Dump Truck 30 Backhoe 31 Mixer truck 32 Concrete pump truck 32a Pressure pipe 33 Asphalt finisher C. Concrete D. Sandbags ES subgrade material G Grout (backfilling material) GE grout pumping equipment H1 Concrete pouring hole H2 Concrete blowout hole H3 Grout injection hole H4 bolt hole L Pavement layer L1 Subbase L2 Upper roadbed L3 base layer L4 surface layer P Connecting pipe RB roadbed S Excavated area T-Tunnel W Outflow prevention wall

Claims

1. An invert block that is installed in the bottom ground of a tunnel and forms an inverted arch shape along the circumferential direction of the tunnel, It is composed of a plurality of steel elements that are long and connected to each other along the axial direction on the longitudinal side and arranged long in the circumferential direction of the tunnel, and these elements are integrated to form a box-shaped hollow structure consisting of an upper plate, a lower plate, and side plates. A support member is installed in a connection opening formed on a longitudinal side of the element, the support member connecting the internal spaces of both elements and supporting a load from above, The upper plate is formed with a concrete pouring hole for pouring concrete into the hollow structure, and a concrete blowout hole for blowing out the poured concrete, Connection pipes connected to the concrete pouring hole and the concrete blowout hole, respectively, are attached to the concrete pouring hole and the concrete blowout hole so as to face upward; The tip of the connecting pipe is located below the asphalt layer of the pavement layer consisting of a roadbed layer and an asphalt layer laminated on the roadbed layer, An invert block characterized by:

2. The tip of the connecting pipe is located at the boundary between the asphalt layer and the roadbed layer.

2. The inverter block according to claim 1.

3. A lid that is removed when pouring concrete is removably attached to the tip of the connecting pipe.

2. The inverter block according to claim 1.

4. A method for pouring concrete into an invert block according to any one of claims 1 to 3, The entire pavement layer in the portion where the invert block is embedded is peeled off up to a position where the tip of the connecting pipe is exposed, A pressure pipe for pressure-feeding concrete is connected to the connecting pipe, Pour concrete into the invert block through the pressure pipe. A method for pouring concrete into an invert block.

5. A method for pouring concrete into an invert block according to any one of claims 1 to 3, The pavement layer of the connecting pipe connected to the concrete pouring hole and the concrete blowout hole of the invert block is peeled off to a position where the tip of the connecting pipe is exposed, A pressure pipe for pressure-feeding concrete is connected to the connecting pipe, Pour concrete into the invert block through the pressure pipe. A method for pouring concrete into an invert block.

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