JP7808565B2 - Invert block and method for pouring concrete into invert block - Google Patents

Description

This invention relates to construction technology to prevent ground swelling inside tunnels.

Depending on the stress conditions around the tunnel, upward pressure from the bottom may cause the road surface to bulge or deform, resulting in areas of bulging, which may reduce the integrity of the tunnel structure.

To do this, construction work will be carried out to install an inverted arch in the ground at the bottom of the tunnel to withstand the pressure pushing up from the bottom.

Note that technology for constructing inverts in tunnels is known, for example, from Patent Document 1 (JP 2020-041381 A).

Japanese Patent Application Laid-Open No. 2020-041381

Inverts in tunnels are typically installed using cast-in-place concrete. However, with cast-in-place concrete, it takes time to set up formwork for pouring the concrete and to allow the concrete to cure, lengthening the construction period. Applying this method to tunnels on expressways currently in service would have a particularly significant impact, as it would extend the lane restriction period.

Another construction method involves manufacturing a precast invert, transporting it into the tunnel, and then installing it. However, this method is not only expensive, but also difficult to install, as the construction 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 needed to lift and install the invert.

The present invention was developed in light of the above-mentioned technical background, and aims to provide technology that enables construction work to prevent ground heave in tunnels to be carried out easily, at low cost, and within a short construction period.

To solve the above problem, the invert block of the present invention described in claim 1 is an invert block that is installed at the bottom of a tunnel and forms an inverted arch shape along the circumferential direction of the tunnel. It is composed of multiple long steel elements that are connected to each other axially along their longitudinal sides and arranged longitudinally along the circumferential direction of the tunnel. These elements are integrated to form a box-shaped hollow structure consisting of upper, lower, and side plates. Support members that connect the internal spaces of both elements and support loads from above are installed in connection openings formed on the longitudinal sides of the elements. 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. Connecting pipes that connect to the concrete pouring holes and concrete outlet holes, respectively, are attached to the concrete pouring holes and concrete outlet holes facing upward, and the tips of the connecting pipes are located below the asphalt layer of a pavement layer consisting of a roadbed layer and an asphalt layer layered on the roadbed layer.

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

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

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 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, and concrete is poured into the invert block via the pressure pipe.

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 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, and concrete is poured into the invert block via the pressure pipe.

According to the present invention, an invert block is constructed and buried in the tunnel pavement simply by installing and interconnecting multiple steel elements on-site. 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 tips of the connecting pipes positioned below the asphalt layer of the pavement layer, which consists of a roadbed layer and an asphalt layer laminated on the roadbed layer.

This means that when pouring concrete into the invert block, the pavement layer only needs to be removed up to the point where the tip of the connecting pipe is exposed, making pouring the concrete easy.

Therefore, by using the invert blocks of the present invention, construction to prevent ground heave in tunnels can be carried out easily, at low cost, and within a short construction period.

This is a plan view showing two invert blocks, one embodiment of the present invention, connected along the circumferential direction of a tunnel through which vehicles and the like pass and installed on the bottom ground of the tunnel. 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. 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. 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. FIG. 10 is an explanatory diagram showing the short-side side plates of adjacent elements. (a) is an explanatory diagram showing the relationship between the short-side side plate and the closure plate before adjacent elements are connected, and (b) is an explanatory diagram showing the relationship between the short-side side plate and the closure plate after adjacent elements are connected. FIG. 2 is a plan view showing the flow direction of concrete poured into the invert block of FIG. 1. FIG. 8 is a cross-sectional view of FIG. 7. 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. 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. 2A and 2B are diagrams showing the excavation machine delivery process, which is one step for continuously installing the invert blocks of Figure 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 in the axial direction of the tunnel. 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. 13A and 13B are diagrams showing the flooring machine delivery process 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. 14A and 14B are diagrams showing the excavation and bedding process following FIG. 13, where (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. 15A and 15B are diagrams showing the unloading and transport machine installation process following FIG. 14, where (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. 16A and 16B are diagrams showing the entry and retreat processes of the component transport vehicle following FIG. 15, where (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. 17A and 17B are diagrams showing the member unloading process following FIG. 16, where (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. 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. 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. 20A and 20B are diagrams showing the backfill injection process following Figure 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. 21A and 21B are diagrams showing the backfilling machine delivery process following Figure 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. 22A and 22B are diagrams showing the backfilling process following FIG. 21, where (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. 23A and 23B are diagrams showing the rolling compaction process following FIG. 22, where (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. 24A and 24B are diagrams showing the process of removing heavy machinery and bringing in paving machinery following FIG. 23, where (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. 25A and 25B are diagrams showing the temporary paving process following FIG. 24, where (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. 26A and 26B are diagrams showing the temporary pavement removal and excavation process following FIG. 25, where (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel. This is a drawing showing the temporary pavement removal process, which is one step in pouring concrete into buried invert blocks, where (a) is an explanatory diagram viewed from above and (b) is an explanatory diagram viewed from the axial cross section of the tunnel. 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. 29 is a drawing 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. 30A and 30B are diagrams showing the re-paving process following Figure 29, where (a) is an explanatory diagram seen from above, and (b) is an explanatory diagram seen from the axial cross section of the tunnel.

An embodiment of the present invention will now be described in detail with reference to the drawings. In the drawings used to explain the embodiment, identical components will generally be designated by the same reference numerals, and repeated explanations will be omitted.

Figure 1 is a plan view showing two invert blocks according to one embodiment of the present invention, connected in the circumferential direction of a tunnel through which vehicles and other vehicles pass and installed in the ground at the bottom of the tunnel; Figure 2 is a cross-sectional view showing the invert blocks of Figure 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 is a cross-sectional view taken along the short side of the leading end of the installation direction and elements other than those at both ends that make up the invert block according to one embodiment of the present invention; and Figure 4 is a cross-sectional view taken along the short side of the rear end of the installation direction element of both ends that make up the invert block according to one embodiment of the present invention.

As shown in Figures 1 and 2, the invert blocks 10 of this embodiment are 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 (one-way traffic with two lanes on each side, or two-way traffic with one lane on each side).

In the actual installation process, after installing the invert blocks 10 across one lane, the invert blocks 10 are installed across the other lane, connecting with the existing invert blocks 10. Depending on the tunnel, three or more invert blocks may be connected circumferentially around the tunnel T to form an inverted arch shape.

As shown in Figure 1, the invert block 10 has an elongated shape that extends circumferentially around the tunnel T in which it is installed, and is composed of four steel elements 10e connected to each other in the axial direction on their longitudinal sides. These elongated elements 10e are installed 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 in the circumferential direction of the tunnel T and are connected in parallel to each other in the axial direction (installation direction) of the tunnel T. Note that the number of elements 10e does not have to be four; any number greater than two will suffice.

The inverter block 10 comprises an upper plate 10ts, a lower plate 10us, and a side plate 10sf, which are separated into each element 10e. In other words, the inverter block 10 has 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. Furthermore, the side plate 10sf comprises 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 lateral side plate 10sf-2, which is a side plate 10sf along the lateral direction (a side plate 10sf located in the circumferential direction of the tunnel). The elements 10e-1 and 10e-4 at both ends comprise an upper plate 10ts, a lower plate 10us, a longitudinal side plate 10sf-1, and a lateral side plate 10sf-2. Elements 10e-2 and 10e-3 each include an upper plate 10ts, a lower plate 10us, and a short-side side plate 10sf-2. These upper plate 10ts, lower plate 10us, and side plate 10sf are welded to each other for each element 10e.

Note that Figures 2 and 8 (described later) show the invert blocks 10 buried in temporary pavement. Details of the temporary pavement will be described later, but the temporary pavement in this embodiment is formed by forming the roadbed RB on the invert blocks 10, and then forming the pavement road layer L (layers in which the lower roadbed L1 (crushed stone (crusher run)), upper roadbed L2 (adjusted-graded crushed stone), base layer L3 (coarse-graded asphalt concrete), and surface layer L4 (dense-graded asphalt concrete) are layered in sequence) on top of the roadbed RB.

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 the connection openings 10ea of the elements 10e, which are formed on the longitudinal sides where the elements 10e are connected, and extend along the longitudinal direction facing each other. Support members 11 for supporting loads from above are installed on these ribs 10eb. As shown in Figure 2, the support members 11 are truss-shaped, and although compressive forces are generated in response to loads from above, they are less susceptible to bending moments. Furthermore, the truss shape creates gaps between the support members 11, allowing the internal spaces of each element 10e that make up the hollow inverter block 10 to communicate with each other.

The support member 11 does not need to be truss-shaped; it can be, for example, a vertical lattice-like structure that can support loads from above and create space that allows the interiors of the elements 10e to communicate with each other (more specifically, space large enough to allow concrete poured in a later process to flow from one element 10e to another).

In addition, connecting plates 10ed and 10ef are provided at the locations where the elements 10e are connected, straddling both elements 10e. Specifically, connecting plate 10ed, which has a long hole (through hole) (not shown) formed in it that is elongated 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, extending over the entire longitudinal length of the upper plate 10ts so as to protrude beyond the upper plate 10ts. Furthermore, connecting plate 10ef, which has a sponge-based sealant 10ee attached to its upper surface, is attached to the underside of the lower plate 10us of one of the elements 10e, extending over the entire longitudinal length of the lower plate 10us, so as to protrude beyond 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 positioned to straddle both elements 10e. Furthermore, a connecting bolt 10eg that passes through the aforementioned long hole formed in the connecting plate 10ed and threads into a nut 10ec is attached to the upper plate 10ts of the other element 10e so that it can be tightened from above.

In this way, the connection bolt 10eg passes through a slot formed in the connection plate 10ed that extends in the axial direction (installation direction) of the tunnel. The slot serves as an adjustment margin, allowing the connection bolt 10eg to thread onto the nut 10ec without being affected by misalignment in the installation direction when the elements 10e are connected. In other words, because the fastening positions of the connection bolt 10eg and 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 nut 10ec can be threaded onto each other at the position of the slot when the elements are in close contact. When the elements 10e are unable to be installed in close contact and are misaligned in the installation direction, the connection bolt 10eg and nut 10ec can be threaded onto each other at the position of the slot when the elements are misaligned. However, if misalignment in the installation direction when the elements 10e are connected 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.

When elements 10e are installed closely together, only small gaps are formed between the upper plates 10ts, lower plates 10us, and shorter side plates 10sf-2 of the elements 10e. However, when elements 10e are installed misaligned in the installation direction, gaps equal to the size of the misalignment are formed between the upper plates 10ts, lower plates 10us, and shorter side plates 10sf-2. These gaps (the small gaps formed when elements 10e are installed closely together, and the gaps corresponding to the misalignment formed when elements 10e are installed misaligned in the installation direction) are blocked between the upper plates 10ts by connecting plate 10ed, between the lower plates 10us by connecting plate 10ef, and between the shorter side plates 10sf-2 by blocking plate 10eh (described below).

In addition, when the elements 10e are connected, the sealing material 10ee is pressed down from above by the lower plate 10us of the other element 10e, causing it to be crushed (for example, crushed to less than 1 mm), thereby forming a seal.

Therefore, by threading 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 to form a seal, making it difficult for soil and sand to enter the hollow inverter block 10 from the outside.

The sealing material 10ee may also be provided on the upper surface of the connecting plate 10ed provided on the upper plate 10ts, over its entire length.

Support bolts 15 penetrate the lower plate 10us of the element 10e and are attached so as to protrude downward. When the element 10e is installed on the ground, a base 16 is sandwiched between the lower end of the support bolt 15 and the ground, allowing the height of the element 10e to be adjusted. The support bolts 15 are provided at both longitudinal ends of the element 10e.

In addition, nuts 17 that thread onto the support bolts 15 are fixed by welding to the holes through which each support bolt 15 passes in the lower plate 10us of the element 10e.

Element 10e-1 (starting element), which is located at the end of the inverter block 10 and is installed first when the inverter block 10 is formed, has two support bolts 15 at each of its longitudinal ends, for a total of four. The other elements 10e-2, 10e-3, and 10e-4 have one support bolt 15 at each of their longitudinal ends, for a total of two. This is because element 10e-1 is installed first and therefore needs to be stabilized with four support bolts 15, whereas elements 10e-2, 10e-3, and 10e-4 are connected sequentially following the 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 the four or two mentioned above, and may be any number greater than that shown in this embodiment. In the illustration, the support bolts 15 provided on elements 10e-2, 10e-3, and 10e-4 are located on the element installation direction side at both longitudinal ends, but they do not have to be located in this position; for example, they may be located on the opposite side of the element installation direction.

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 bolt hole H4, which passes vertically through element 10e, and has a wrench hole (such as a hexagonal wrench hole) formed in its head. A long wrench (such as a hexagonal wrench) is then inserted from the top of bolt hole H4 to turn the support bolt 15 and adjust the height of element 10e-1.

Also, as shown in Figure 3, the support bolt 15 located on the element installation 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 (support bolts 15 shown on elements 10e-2 and 10e-3 in Figure 3) located between element 10e-1 and element 10e-4 (the element located at the end of the inverter block 10 and installed last when forming the inverter block 10: terminal element) are located within reach of an operator through the connection opening 10ea, and are therefore positioned so that they can be rotated from the connection opening 10ea.

Furthermore, as shown in Figure 4, the support bolt 15 of element 10e-4 is positioned so that it can be rotated through the gap between element 10e-4 and the ground, since when 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 into 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 element 10e-4 and the ground.

The structure of the side plates 10sf of the inverter block 10 will now be explained using Figures 5 and 6. Figure 5 is an explanatory diagram showing the short-side side plates of adjacent elements, and Figure 6 is an explanatory diagram showing the relationship between the short-side side plates of adjacent elements and the closure plate, with (a) showing the adjacent elements before they are connected, and (b) showing them after they are connected.

The inverter block 10 has separate side plates 10sf (longitudinal side plates 10sf-1, lateral side plates 10sf-2) for each element 10e. As mentioned above, a gap is formed between the lateral side plates 10sf-2 of adjacent elements 10e, corresponding to the fastening position of the connecting bolt 10eg and nut 10ec relative to the elongated hole formed in the connecting plate 10ed (see Figure 6(a)).

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

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). This allows the closure plate 10eh to close the aforementioned gap that forms when elements 10e (here, elements 10e-1 and 10e-2) are connected. Furthermore, once elements 10e are connected, 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.

In Figure 1, multiple (two in this example) H-shaped steel piles 12 are erected. These piles 12 serve both as guardrail supports for separating two lanes and as support piles for cross piles used during ground excavation (cross piles used as retaining walls when excavating the ground to install invert blocks 10). Therefore, recesses are formed in the elements 10e that make up the invert blocks 10 to avoid interference with the piles 12.

As shown in Figure 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 a connecting plate (not shown). That is, the connecting plate is fixed to the invert block 10 by threading a bolt through a through hole formed in the connecting plate into the nut inside the connecting hole 13. The same connecting plate is then bolted to adjacent invert blocks 10, connecting the adjacent invert blocks 10 via the connecting plate. Note that there may be only one connecting hole 13, rather than multiple holes as in this embodiment.

In addition, as shown in Figure 2, at two longitudinal positions on the upper plate 10ts of each element 10e, hanging fittings 14 are provided that can engage with hooks attached to the ends of a wire, so that the element 10e can be hung by the wire of a crane (e.g., a crawler crane) and installed on the ground at the bottom of the tunnel T.

Furthermore, as shown in Figures 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 installed in the ground at the bottom of the tunnel, thereby filling 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 space between the element 10e and the ground.

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 will be blown out.

As shown in the figure, 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) on the upper plate 10ts of the invert block 10 when it is installed on the bottom ground of the tunnel T, and concrete blowout holes H2 are formed in two locations at high positions (corners on the side wall side of the tunnel T) on the upper plate 10ts of the invert block 10 when it is installed on the bottom ground of the tunnel T. Note that the number and positions of concrete pouring holes H1 and concrete blowout holes H2 are not limited to those shown in this embodiment. However, it is desirable that concrete blowout holes H2 be formed in corners on the side wall side of the tunnel T when it is installed so that internal air can be smoothly exhausted during concrete pouring.

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 central elements 10e (10e-2, 10e-3). However, if there is an even number of elements 10e and these elements 10e are installed at an incline in the axial direction of the tunnel T, it is desirable to form the concrete pouring hole H1 in the lower of the two central elements 10e. Note that in an invert block 10 composed of an odd number of elements 10e, the concrete pouring hole H1 is formed in the central element 10e.

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).

In addition, in a later process, concrete will be poured while the invert block 10 is buried in the ground at the bottom of the tunnel T. 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.

In this embodiment, the connecting pipe P is a steel pipe with a diameter of approximately 6 inches, 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 concrete blowout hole H2 and the diameter of the pressure pipe, and is not limited to 6 inches as in this embodiment.

Here, we will explain the flow of concrete when pouring it into the invert blocks 10 in a later process (a process after the invert blocks 10 are installed) 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.

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 in 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 in the bottom ground of the tunnel T.

As shown in Figures 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 the air inside out through the concrete blowout hole H2. When concrete C is blown out from the highest concrete blowout hole H2 (more specifically, the connecting pipe P attached to the concrete blowout hole H2), it can be assumed that the entire interior of the invert block 10 has been filled with concrete C.

As shown in Figure 8, the tips of the connecting pipes P attached to the concrete pouring hole H1 and the concrete blowout hole H2 are located at the boundary between the base layer L3 and upper subgrade L2 that make up the pavement 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 subsequent process, the two layers (i.e., the asphalt layers) of the surface layer L4 and base layer L3 are peeled away 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 the pressure pipe from the pump truck via a joint (not shown).

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; there is no need to remove the roadbed RB to expose the invert block 10 itself, making it easier to pour the concrete.

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 of the connecting pipe P needs to be located at the boundary between the roadbed layer and the asphalt layer or below that boundary (i.e., below the asphalt layer). If the tip of the connecting pipe P is located 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 part of the roadbed layer are peeled off to expose the tip of the connecting pipe P.

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 surface layer L4) without having to peel off the roadbed layer (here, the lower roadbed L1 and upper roadbed L2).

The area of temporary paving 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 a highway, it is desirable to remove the temporary paving from the entire area where the invert blocks 10 into which concrete will be poured are buried. Furthermore, when constructing a general road, it is sufficient to only remove the temporary paving around the connecting pipe P.

As explained above, the invert block 10 of this embodiment, which is embedded 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 along their longitudinal sides, and has a hollow structure with an upper plate 10ts, a lower plate 10us, and a side plate 10sf. Furthermore, a support member 11 is installed inside the connection opening 10ea of the elements 10e, formed on the longitudinal side where the elements 10e are connected, to connect the internal spaces of both elements 10e and support loads from above.

Furthermore, the upper plate 10ts has a concrete pouring hole H1 for pouring concrete into its hollow interior, and a concrete outlet hole H2 from which the poured concrete is ejected. Connecting pipes P are attached to the concrete pouring hole H1 and concrete outlet 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.

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; there is no need to remove the roadbed RB to expose the invert block 10 itself, making it easier to pour the concrete.

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

Next, the process for installing the invert block 10 described above in tunnel T will be explained using Figures 11 to 26. As an example, we will explain the case where the invert block 10 is installed under one of the lanes in tunnel T, which has two lanes on each side and is one-way traffic.

Figure 11 is an explanatory diagram showing the excavation machine delivery process, which is one process for continuously installing the invert blocks of Figure 1 along the axial direction of the tunnel; Figure 12 is an explanatory diagram showing the initial excavation process following Figure 11; Figure 13 is an explanatory diagram showing the bedding machine delivery process following Figure 12; Figure 14 is an explanatory diagram showing the excavation and bedding process following Figure 13; Figure 15 is an explanatory diagram showing the unloading and transport machine delivery process following Figure 14; Figure 16 is an explanatory diagram showing the entry and retreat process of the component transport vehicle following Figure 15; Figure 17 is an explanatory diagram showing the component unloading process following Figure 16; Figure 1 8 is an explanatory diagram showing the temporary member placement process following Figure 17, Figure 19 is an explanatory diagram showing the member installation process following Figure 18, Figure 20 is an explanatory diagram showing the backfill injection process following Figure 19, Figure 21 is an explanatory diagram showing the backfilling machine delivery process following Figure 20, Figure 22 is an explanatory diagram showing the backfilling process following Figure 21, Figure 23 is an explanatory diagram showing the compaction process following Figure 22, Figure 24 is an explanatory diagram showing the heavy equipment removal and paving machine delivery process following Figure 23, Figure 25 is an explanatory diagram showing the temporary paving process following Figure 24, and Figure 26 is an explanatory diagram showing the temporary paving removal and excavation process following Figure 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.

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 the invert blocks 10, while the other lane is designated as a traffic lane open to general vehicles. Then, a trailer 21 carrying a backhoe 20 (e.g., a 0.45-class backhoe) acting as an excavation machine is driven from the traffic lane into the restricted zone, where the backhoe 20 is unloaded and transported into the restricted zone (excavation machine transport process). The trailer 21 then exits the tunnel from the end of the restricted zone (the end opposite the entrance).

In this embodiment, a backhoe is used as the heavy machinery for excavating the ground, but a hydraulic excavator other than a backhoe may also be used.

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

Next, as shown in Figure 13, a trailer 21 carrying a small backhoe 23 (e.g., 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). 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) introduced in the traffic lane that limits the speed of following general vehicles to the speed limiter. Once the trailer 21 is ahead of the speed limiter, it exits the restricted zone into the traffic lane and exits the tunnel.

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

Next, as shown in Figure 15, a trailer (not shown) carrying a crawler crane 24 (e.g., a 4.9-ton crawler crane) serving as an unloading and transporting machine is driven from the traffic lane into the restricted zone, where the crawler crane 24 is lowered just before the excavated area S (on the opposite side from the direction of excavation and bedding of the excavated area S) (unloading and transporting machine delivery process). Because the excavated area S is ahead and the trailer cannot proceed through the restricted zone, safety is ensured by a speed limiter vehicle (not shown) introduced into the traffic lane that limits the speed of following general vehicles. Once the trailer is ahead of the speed limiter vehicle, 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.

Next, as shown in Figure 16, a dump truck (e.g., a 4-ton dump truck) 25, serving as a component transport vehicle, carrying 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). Note that the excavation and bed-laying process (see Figure 14) continues during this time.

Next, as shown in Figure 17, the element 10e loaded onto the dump truck 25 is unloaded by the crawler crane 24 (component unloading process). Note that during this time, the excavation and bed-laying process (see Figure 14) continues.

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. Furthermore, since the dump truck 25 carrying the element 10e is unable to proceed through the restricted zone due to the excavated area S ahead, safety is ensured by a speed limiter (not shown) introduced in the traffic lane that limits the speed of following general vehicles to this speed limiter. Once the dump truck 25 is ahead of the speed limiter, it exits the restricted zone into the traffic lane and exits the tunnel. Note that the excavation and bedding process (see Figure 14) continues during this time.

Next, as shown in Figure 19, the unloaded elements 10e are installed in the excavated area S using a crawler crane 24 (component installation process). That is, as shown, the longitudinal direction of the elements 10e is oriented circumferentially around the tunnel, and the crawler crane 24 installs the elements 10e along the axial direction (installation direction) of the tunnel T. Then, the extension and contraction amounts of the support bolts 15 are adjusted to align the relative heights of the four elements 10e, and the connecting bolts 10eg are threaded into the nuts 10ec to connect the elements 10e together, forming an inverter block 10 that integrates these elements 10e (see Figures 3 and 4).

As mentioned above, in this embodiment, four elements 10e are installed to form one invert block 10. The axial length of the tunnel T made up of these elements 10e is, for example, 3m. However, this length varies depending on the number of elements 10e installed and the width of the elements 10e, and is not limited to 3m. During this time, the excavation and bedding process (see Figure 14) continues.

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

In more detail, the inverter block 10 may be formed by repeatedly installing the elements 10e one by one, aligning their heights, and connecting them. Alternatively, the elements 10e that make up the inverter block 10 may be installed one by one, aligning their heights, and then 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 installed 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.

Next, once one invert block 10 has been formed, as shown in Figure 20, grout (backfilling material) G is injected between the invert block 10 and the installation ground (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.

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 spilling out. Sandbags D are placed on the outside of the anti-flow walls W to prevent them from collapsing. A dump truck (e.g., a 2-ton dump truck) 26 loaded with grout G and grout pumping equipment GE, such as a pump for pumping the grout G, then enters the restricted zone, and grout G is injected between the bottom of the invert blocks 10 and the installation ground through the grout injection holes H3 (see Figures 1, 3, and 4) provided in each element 10e. In this embodiment, grout is injected after one day's worth of construction. However, the timing of grout injection is not limited to one day's worth of construction and may be other injection timings. Furthermore, materials other than sandbags D may be used to prevent the spill prevention wall W from tipping over.

Note that between the backfill material injection process and the backfilling process described below, connecting pipes P (see Figures 2 and 8) are attached to the concrete pouring holes H1 and the concrete blowout holes H2 formed in each element 10e. Furthermore, 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 Figures 20 to 26. Furthermore, the excavation and bedding process (see Figure 14) continues during this time.

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 restricted zone (backfilling machine delivery process). Note that the excavation and bedding process (see Figure 14) continues during this time.

Next, as shown in Figure 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 the backhoe 27 and the 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, integrated elements 10e), backfilling the area (backfilling process). In Figures 22 and 23, the symbol ES indicates the subgrade material, which is backfill soil. Note that the dump truck 29, now empty of the subgrade material, moves from the restricted zone to the traffic lane and exits the tunnel. During this time, the excavation and bedding process (see Figure 14) continues. Furthermore, while the illustrated example shows the installation of the elements 10e required to form one invert block 10 before backfilling, it is of course also possible to install the elements 10e required to form multiple invert blocks 10 before backfilling.

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). During 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.

For example, if Monday through Friday were considered one work unit so that the restricted zone was also open to general traffic on Saturdays and Sundays, each of the above-described processes, from the excavation and bed-laying process (Figure 14) to the compaction process (Figure 23), would be 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 would then be buried in the roadbed RB, which is made by compacting the roadbed material ES. Adjacent invert blocks 10 are connected to each other by threading bolts through the through-holes formed in the connecting plates with nuts in the connecting holes 13, as described above, to ensure that they are all the same height.

Note that the method for progressing through each task unit and the steps within each task unit is not limited to that described in this embodiment, and can of course be freely set.

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

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

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, each of the processes from the excavation and laying process (Figure 14) to the compaction process (Figure 23) described above is repeated sequentially from Monday to Thursday. Furthermore, after the final compaction process (Figure 23) on Thursday is completed, the process of removing the excavation equipment and bringing in the paving equipment (Figure 24) is carried out, and on Friday the temporary paving process (Figure 25) is carried out.

Once multiple continuous invert blocks 10 (continuous invert block structure) have been buried in part or all of one lane of tunnel T in the manner described above, the next process involves pouring concrete into the buried invert blocks 10. Next, the process of pouring concrete into the invert blocks 10 will be explained using Figures 27 to 30.

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-paving process 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.

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 tips of the connecting pipes P attached to the concrete pouring holes H1 and concrete blowout holes H2 (temporary pavement removal process). As mentioned above, in this embodiment, the tips of the connecting pipes P are located at the boundary between the base layer L3 and upper subgrade L2 that make up the pavement road layer L. Therefore, the two layers (asphalt layers) of the surface layer L4 and base layer L3 are removed, but the two layers (subgrade layers) of the upper subgrade L2 and lower subgrade L1 are not removed. However, the surface layer L4, base layer L3, upper subgrade L2, and lower subgrade L1 are not shown in Figures 27 to 29.

As mentioned above, the area of temporary paving that is 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 blocks 10 into which concrete will be poured are buried; however, in this example, the latter area is considered to be removed.

In addition, in this embodiment, when pouring concrete into existing invert blocks 10, each of the processes from the excavation and flooring process (FIG. 14) to the compaction process (FIG. 23) described above 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 embedding the invert blocks 10 in the unexcavated areas are carried out in parallel in different areas, making it possible to complete the entire series of tasks in a shorter construction period.

Now, after the tip of the connecting pipe P is exposed during the temporary pavement removal process shown in Figure 27, a mixer truck 31 transporting ready-mixed concrete and a concrete pump truck 32, which docks with the mixer truck 31, receives the ready-mixed concrete in its hopper, and pressure-feeds the ready-mixed concrete through a pressure pipe 32a using an equipped pump (not shown), are introduced into the restricted zone, as shown in Figure 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.

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 regular concrete or fluidized concrete, can also be used for the concrete to be poured.

Once concrete pouring has begun during the concrete pouring start process shown in Figure 28, the pressure pipe 32a of the concrete pump truck 32 is connected in sequence 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.

When pouring concrete into each invert block 10, the connecting pipe P attached to the two concrete blowout holes H2 from which concrete is blown out first is capped as soon as it starts to flow 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 flow out. 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.

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 mentioned 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.

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-paving (re-paving process). If only the temporary paving around the connecting pipe P has been removed, the re-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, which was previously used to bury the invert blocks 10 (see Figure 25).

In this way, concrete is poured into the invert blocks 10 buried in one lane of tunnel T, creating an invert. Once the invert has been created by burying the invert blocks 10 (Figures 11-26) and pouring concrete (Figures 27-30) 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 tunnel axis, is installed in multiple rows (two rows in this embodiment) along the tunnel axis. Two invert blocks 10 (two inverts) facing each other circumferentially of tunnel T form an inverted arch shape along the circumferential direction of tunnel T (see Figure 2). When installing the invert blocks 10 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.

Finally, the entire area of the tunnel T that has been temporarily repaved is stripped away, and the final finishing process of permanent paving (paving at the original thickness) is carried out, completing the entire process.

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 spirit of the claims.

The above explanation has been about installing the invert blocks of the present invention in tunnels that are currently in use, but they can also be installed in newly constructed tunnels.

10 Inverter block 10e Element 10ea Connection opening 10eb Rib 10ec Nut 10ed Connection plate 10ee Sealing material 10ef Connection plate 10eg Connection bolt 10eh Blocking plate 10sf Side plate 10sf-1 Longitudinal side plate 10sf-2 Shortitudinal side plate 10ts Upper plate 10us Lower plate 11 Support member 12 Pile 13 Connecting hole 14 Lifting hardware 15 Support bolt 16 Base 17 Nut 20 Backhoe 21 Trailer 22 Dump truck 23 Backhoe 24 Crawler crane 25 Dump truck 26 Dump truck 27 Backhoe 28 Roller compaction roller 29 Dump truck 30 Backhoe 31 Mixer truck 32 Concrete pump truck 32a Pressure pipe 33 Asphalt finisher C Concrete D Sandbag ES Subgrade material G Grout (backfill material)
GE Grout pumping equipment H1 Concrete pouring hole H2 Concrete blowout hole H3 Grout injection hole H4 Bolt hole L Pavement road layer L1 Lower subgrade L2 Upper subgrade L3 Base layer L4 Surface layer P Connecting pipe RB Subgrade S Excavated area T Tunnel W Runoff prevention wall

Claims (5)

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: 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. 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. 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. 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.