Invert concrete hardening accelerator

Abstract

To accelerate the hardening of invert concrete. [Solution] A hardening accelerator for curing and accelerating the hardening of invert concrete 101 poured into the lower part of a tunnel 100, comprising curing means 20, 30, 40 attached to the lower surface of a structure 90 installed at intervals above the invert concrete 101, and for curing the invert concrete 101.

Description

Technical Field

[0001] The present invention relates to a device for accelerating the curing of invert concrete.

Background Art

[0002] In a tunnel, when the geology is weak, etc., by connecting the bases between the both side walls with invert concrete in an inverted arch shape, the bearing capacity of the tunnel is increased to prevent deformation and settlement. In the construction of this invert concrete, a temporary trestle is installed in the construction section, or construction is carried out on one side at a time in the tunnel width direction, so that passage of vehicles and people for material transportation, etc. is ensured. For example, Patent Document 1 below discloses a conventional trestle.

[0003] In the technique described in Patent Document 1, with a trestle installed on one side in the tunnel width direction, the ground is excavated on the other side in the tunnel width direction, and then the trestle is moved to the other side in the tunnel width direction, and the remaining ground is excavated on one side in the tunnel width direction. Then, a formwork is installed at the excavation location, and invert concrete is placed. By repeating this operation for each predetermined section in the tunnel extension direction, the invert concrete is constructed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the conventional construction of invert concrete using a trestle, since the upper part of the invert concrete is covered by the trestle, proper curing is not carried out, and it is difficult to accelerate the curing.

[0006] The present invention aims to accelerate the hardening of invert concrete. [Means for solving the problem]

[0007] (1) The present invention relates to a hardening accelerator for curing and accelerating the hardening of invert concrete poured into the lower part of a tunnel, It is attached to the underside of a structure installed at intervals above the invert concrete and is equipped with a curing means for curing the invert concrete.

[0008] With this configuration, even if the invert concrete is covered by a structure such as a pier, the invert concrete can be cured and hardened by the curing means provided on the underside of the structure. Therefore, the construction period for the invert concrete can be shortened and its quality can be improved.

[0009] (2) In (1) above, the curing means includes at least one of a water supply unit that supplies water to the surface of the invert concrete and a heating unit that heats the invert concrete. This configuration allows for wet curing to adjust the moisture level of the invert concrete, or temperature-controlled curing to adjust the temperature of the invert concrete.

[0010] (3) In (1) or (2) above, the curing means includes a covering portion having a sheet that covers the invert concrete from above. This configuration makes it possible to maintain the moisture level and temperature of the invert concrete.

[0011] (4) In any of (1) to (3) above, the structure is a pier that straddles the invert concrete in the direction of the tunnel extension. This configuration allows for optimal curing of the invert concrete beneath a pier that spans the invert concrete.

[0012] (5) In the above (4), other protective measures are provided attached to the left and right sides of the pier. Since the pier spanning the invert concrete is used to secure a vehicle path on one side in the tunnel width direction, invert concrete exists not only below the pier but also on the other side in the tunnel width direction. With the above configuration, the invert concrete located below the pier can be cured by the curing means attached to the underside of the pier, and the invert concrete located to the side of the pier can be cured by other curing means attached to the side of the pier. [Effects of the Invention]

[0013] According to the present invention, even if the upper part of the invert concrete is covered by a structure such as a pier, the invert concrete can be cured and hardened by a curing means provided on the underside of the structure. [Brief explanation of the drawing]

[0014] [Figure 1] This is a front view showing an invert concrete hardening acceleration device according to an embodiment of the present invention installed inside a tunnel. [Figure 2] This is a side view showing the hardening accelerator installed inside the tunnel. [Figure 3] This is a plan view showing the hardening accelerator installed inside the tunnel. [Figure 4] This is a front view of the curing accelerator. [Figure 5] This is a cross-sectional view taken along the arrow BB in Figure 4. [Figure 6A] This is a front view showing the contracted state of the expansion / contraction member of the lateral construction section in the hardening acceleration device. [Figure 6B] This is a front view showing the expansion member of the lateral construction section in an extended state. [Figure 7A] This is a plan view showing the expansion joint of the lateral construction section in a contracted state. [Figure 7B] This is a plan view showing the expansion member of the lateral construction section in an extended state. [Figure 8A] It is a bottom view showing a lower construction part in a hardening acceleration device. [Figure 8B] It is a sectional view taken along line A - A of FIG. 7. [Figure 9A] It is a front view showing a construction method of inverted concrete. [Figure 9B] It is a front view showing a construction method of inverted concrete. [Figure 9C] It is a front view showing a construction method of inverted concrete. [Figure 9D] It is a front view showing a construction method of inverted concrete. [Figure 9E] It is a front view showing a construction method of inverted concrete. [Figure 9F] It is a front view showing a construction method of inverted concrete. [Figure 9G] It is a front view showing a construction method of inverted concrete. [Figure 9H] It is a front view showing a construction method of inverted concrete.

Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view showing a state where a hardening acceleration device for inverted concrete according to an embodiment of the present invention is installed in a tunnel. FIG. 2 is a side view showing a state where the hardening acceleration device is installed in the tunnel. FIG. 3 is a plan view showing a state where the hardening acceleration device is installed in the tunnel. In this specification, the direction across the tunnel 100 (the left - right direction in FIG. 1) is referred to as the tunnel width direction (or the left - right direction), and the direction in which the tunnel 100 extends (the left - right direction in FIG. 2) is referred to as the tunnel extension direction.

[0016] The hardening accelerator 10 of this embodiment cures the invert concrete 101 poured into the tunnel 100 and accelerates its hardening. In this specification, "curing" refers to work to adjust or maintain the moisture state and temperature of the invert concrete 101, such as wet curing (spraying water, flooding, applying damp cloth, etc.) to control the moisture state of the invert concrete 101, and temperature-controlled curing (heat supply, insulation, etc.) to control the temperature.

[0017] The invert concrete 101 is constructed sequentially in predetermined sections S1 along the tunnel's lengthwise direction. The hardening accelerator 10 in this embodiment is attached to a pier 90 installed inside the tunnel 100. The pier 90 is installed to span the construction section (curing section) S1 along the tunnel's lengthwise direction during the construction of the invert concrete 101, allowing vehicle traffic in the construction section S1. The pier 90 is installed on one side in the tunnel's widthwise direction. The pier 90 has a running section 91 that extends in the tunnel's lengthwise direction and forms a road surface for vehicles, and side walls 92 provided on both sides of the running section 91 in the tunnel's widthwise direction. The pier 90 is movable between one side and the other in the tunnel's widthwise direction. The running section 91 has slopes 93 at both ends in the tunnel's lengthwise direction.

[0018] The hardening accelerator 10 of this embodiment is configured to cure the entire construction section S1 of the poured invert concrete 101. The hardening accelerator 10 of this embodiment has a lateral construction section (lateral curing section) 11 installed on both the left and right sides of the pier 90, and a lower construction section (lower curing section) 12 installed below the pier 90.

[0019] (Side construction part 11) Figure 4 is a front view of the curing accelerator. As shown in Figures 1 and 4, each lateral construction section 11 includes a covering section 20, a water supply section 30, a heating section 40, and a support section 14 that supports them. The covering section 20, the water supply section 30, and the heating section 40 constitute a curing means for adjusting and maintaining the wetness and temperature of the invert concrete 101.

[0020] The support portion 14 of the lateral construction portion 11 is attached to the outer surface in the tunnel width direction of the side wall 92 of the pier 90. The support portion 14 has a base portion 61 (see Figure 4) connected to the pier 90, and a plurality of expandable members 51 attached to the base portion 61 that expand and contract in the tunnel width direction. The base portion 61 is detachably attached to the pier 90. The plurality of expandable members 51 are arranged at intervals in the tunnel length direction, as shown in Figure 3. Although the expandable members 51 expand and contract horizontally in the tunnel width direction, they do not necessarily have to expand and contract strictly in the horizontal direction. They may expand and contract in a direction that includes a vertical component in addition to the horizontal component, for example, in a direction that is inclined up or down within a range of ±30° with respect to the strictly horizontal direction.

[0021] Figure 5 is a cross-sectional view taken along the BB arrow in Figure 4. Figure 6A is a front view showing the expansion / contraction member of the lateral construction section in the hardening accelerator in a contracted state. Figure 6B is a front view showing the expansion / contraction member of the lateral construction section in an extended state. The expandable member 51 of this embodiment has a pantograph structure in which a plurality of link members 52 are connected by shafts 53 and 54. Specifically, the expandable member 51 is formed by connecting two strip-shaped link members 52 at their central portions crossed at each end of a single shaft 53, with multiple such sets being arranged in the tunnel width direction, and the longitudinal ends of adjacent sets of link members 52 being rotatably connected by shafts 54. The lower end of the link member 52 located closest to the pier 90 is pivotably supported by the base 61 of the support 14 via a connecting member 58, and the upper end of the link member 52 located closest to the pier 90 is vertically movable supported by the base 61 of the support 14. Therefore, the expandable member 51 can expand and contract in the tunnel width direction while maintaining a horizontal position with respect to the base 61.

[0022] The retractable member 51 has an operating section 56 for extending and retracting. In this embodiment, the operating section 56 includes a lever that is operated manually. The operating section 56 amplifies the operating force of the lever using an actuator or a force-amplifying mechanism (not shown) to forcibly swing the link member 52, thereby extending and retracting the entire retractable member 51 in the tunnel width direction.

[0023] As shown in Figure 1, the maximum length of the expandable member 51 when extended is greater than the distance L1 from the other end of the pier 90 located on one side in the tunnel width direction to the inner surface of the tunnel on the other side in the tunnel width direction. The minimum length of the expandable member 51 when contracted is less than the distance L2 from the one end of the pier 90 located on one side in the tunnel width direction to the inner surface of the tunnel on that side in the tunnel width direction.

[0024] The covering portion 20 is intended to retain moisture and heat in the invert concrete 101. The covering portion 20 includes a sheet 21 that covers the invert concrete 101 from above, and a winding roll (winding member) 22 that winds up and retrieves the sheet 21.

[0025] Sheet 21 is formed from a material that restricts the permeability of air and water and maintains the temperature and humidity of the space covered by Sheet 21 (heat retention, water retention, etc.). For example, Sheet 21 is formed from a synthetic resin or rubber material that has no or low water permeability. In Figures 2 and 3, etc., Sheet 21 is hatched to make it easier to see. Sheet 21 has a length in the tunnel extension direction that can cover the invert concrete 101 in the construction section S1. Specifically, sheet 21 has a length in the tunnel extension direction that is the same as, slightly less than, or greater than the length in the tunnel extension direction of the construction section S1. In addition, sheet 21 has a length in the tunnel width direction that is greater than the distance L1 shown in Figures 1 and 3. Therefore, sheet 21 can cover the upper part of the invert concrete 101 in the tunnel width direction up to at least the distance L1.

[0026] As shown in Figures 6A and 6B, the sheet 21 is positioned on the upper part of the expandable member 51 in the support section 14 and is connected, for example, to the outer end of the expandable member 51 in the tunnel width direction. The winding roll 22 is rotatably supported on the base 61 of the support section 14 near the side wall 92 of the pier 90. The winding roll 22 is biased in the direction of winding up the sheet 21. When the expandable member 51 is retracted from an extended state, the sheet 21 moves together with the expandable member 51 and is wound up and collected on the winding roll 22. Conversely, when the expandable member 51 is extended from a retracted state, the sheet 21 moves together with the expandable member 51 and is pulled out from the winding roll 22. The outer end of the sheet 21 in the tunnel width direction hangs down beyond the expandable member 51. As shown in Figure 1, the upper surface of the sheet 21 is positioned, for example, within a height range H1 from the upper end (outer end in the tunnel width direction) of the invert concrete 101. This height H1 is set, for example, within a range of 2.0m or less. By setting it within such a range, wet curing and temperature-controlled curing can be properly implemented.

[0027] Since the lateral construction sections 11 are provided on both sides of the pier 90 in the tunnel width direction, the sheet 21 of the covering section 20 can cover the invert concrete 101 located on both sides of the pier 90 in the tunnel width direction. The winding roll 22 may be configured to automatically pull out and / or wind up the sheet 21 using a motor or the like. In this case, the winding roll 22 may be operated in conjunction with the extension and retraction operation of the telescopic member 51.

[0028] The water supply section 30 of the lateral construction section 11 includes a water supply nozzle 31, a water supply hose 32, and a winding roll (winding member) 33. The water supply hose 32 extends in the direction of the tunnel width. The water supply hose 32 is supported by the expandable member 51 of the support section 14. Multiple water supply hoses 32 are provided corresponding to multiple expandable members 51. Therefore, the multiple water supply hoses 32 are arranged at intervals in the direction of the tunnel extension. As shown in Figure 5, each water supply hose 32 is positioned above the shaft 53 in each expandable member 51 and is supported by the shaft 53. The water supply hose 32 is connected to the shaft 53, for example, at its outer end in the direction of the tunnel width.

[0029] Multiple water supply nozzles 31 are provided at various locations on each water supply hose 32. The multiple water supply nozzles 31 are spaced apart along the longitudinal direction of the water supply hose 32, i.e., in the tunnel width direction. Each water supply nozzle 31 sprays the water flowing through the water supply hose 32 onto the surface of the invert concrete 101. Specifically, the water supply nozzles 31 spray water in a shower-like or mist-like manner, diffusing it horizontally.

[0030] The water supply section 30 is equipped with multiple water supply hoses 32 spaced apart in the direction of the tunnel's extension and water supply nozzles 31 spaced apart in the direction of the tunnel's width, so that water can be sprayed over the entire surface of the invert concrete 101 on the side of the pier 90, making the surface of the invert concrete 101 wet.

[0031] The winding roll 33 is rotatably supported on the base 61 of the support section 14. Multiple winding rolls 33 are provided, one for each of the multiple water supply hoses 32. The end of the water supply hose 32 on the pier 90 side is wound onto the winding roll 33. The winding roll 33 is biased, for example, in the direction of winding the water supply hose 32. When the telescopic member 51 is retracted from an extended state, the water supply hose 32 moves together with the telescopic member 51 and is wound onto the winding roll 33 for retrieval. Conversely, when the telescopic member 51 is extended from a retracted state, the water supply hose 32 moves together with the telescopic member 51 and is pulled out from the winding roll 33.

[0032] Multiple water supply hoses 32 are connected to a water source 34 and a pump 35 (see Figure 8A). The water source 34 is, for example, a water storage tank. The water storage tank 34 can be installed on the pier 90 or the support structure 14. The pump 35 draws water from the water storage tank 34 and supplies it to each water supply hose 32.

[0033] As shown in Figures 4 and 5, the heating section 40 of the lateral construction section 11 has a heater 41. The heater 41 in this embodiment is an electric heater, and power is supplied from a power supply device 44 (see Figure 8A), such as a generator or battery. The heater 41 is connected to the power supply device 44 by an electric wire 43. The heater 41 is attached to and supported by an expandable member 51 in the support section 14. The heater 41 in this embodiment is formed in a rod shape, and its longitudinal direction is oriented in the direction of tunnel extension. As shown in Figure 5, the heater 41 is attached to an axis 53 in the expandable member 51.

[0034] Multiple heaters 41 are provided at intervals along the longitudinal direction of the expansion members 51. Each of the multiple heaters 41 is attached to one of the multiple shafts 53 in the expansion member 51. Multiple heaters 41 are provided on each of the multiple expansion members 51. Therefore, the multiple heaters 41 are arranged at intervals in the tunnel length direction and the tunnel width direction. As a result, the heaters 41 can heat the entire surface of the invert concrete 101 on the side of the pier 90 in the tunnel width direction. Also, since the heaters 41 are attached to the expansion members 51, they move in the tunnel width direction as the expansion members 51 expand and contract.

[0035] (Lower construction section 12) Figure 8A is a bottom view showing the lower construction section of the curing accelerator. Figure 8B is a cross-sectional view of AA in Figure 7. Note that sheet 21 is omitted in Figure 8B. As shown in Figure 4, the lower construction section 12 is located below the pier 90. The lower construction section 12 cures the invert concrete 101 poured below the pier 90 and promotes its hardening. Similar to the lateral construction section 11, the lower construction section 12 has a covering section 20, a water supply section 30, and a heating section 40.

[0036] The covering portion 20 has a sheet 21. It is attached to the bottom surface of the running portion 91 on the pier 90. The sheet 21 has a length in the tunnel extension direction that can cover the invert concrete 101 in the construction section S1. Specifically, the sheet 21 has a length in the tunnel extension direction that is the same as, slightly less than, or greater than the tunnel extension direction of the construction section S1.

[0037] Furthermore, the sheet 21 has a length in the tunnel width direction that is greater than the length of the running section 91 on the pier 90 in the tunnel width direction. Both ends of the sheet 21 in the tunnel width direction protrude outward from the pier 90 in the tunnel width direction and are attached to and supported on the lower surface of the support section 14 on the lateral construction section 11. Therefore, the sheet 21 can cover the entire invert concrete 101 from above in both the tunnel length direction and the tunnel width direction in the area below the pier 90 (downward projection area).

[0038] As indicated by the symbol L1 in Figure 6B, both ends of the sheet 21 in the tunnel width direction in the lower construction section 12 overlap vertically with the inner (pier 90 side) end of the sheet 21 in the tunnel width direction in the lateral construction section 11. Therefore, in a top view, the sheet 21 of the lateral construction section 11 and the lower construction section 12 can cover the entire invert concrete 101 in the tunnel width direction without any gaps.

[0039] As shown in Figures 8A and 8B, the water supply section 30 includes a water supply nozzle 31 and a water supply hose 32. The water supply hose 32 is attached to and supported on the bottom surface of the running section 91 of the pier 90. The water supply hose 32 extends in the direction of the tunnel's length. Multiple water supply hoses (two in this embodiment) are provided at intervals in the direction of the tunnel's width.

[0040] The water supply nozzles 31 are provided at multiple locations on each water supply hose 32. The multiple water supply nozzles 31 are spaced apart in the longitudinal direction of the water supply hose 32, that is, in the direction of tunnel extension. Each water supply nozzle 31 sprays the water flowing through the water supply hose 32 onto the surface of the invert concrete 101.

[0041] The water supply section 30 is equipped with multiple water supply hoses 32 spaced apart in the direction of the tunnel's extension and water supply nozzles 31 spaced apart in the direction of the tunnel's width, so that water can be sprayed over the entire surface of the invert concrete 101 below the pier 90, keeping the surface of the invert concrete 101 moist.

[0042] The heating section 40 in the lower construction section 12 has a heater 41. The heater 41 in this embodiment is an electric heater, and power is supplied from a power supply device 44 such as a generator or battery. The heater 41 is connected to the power supply device 44 by an electric wire 43. The heater 41 is formed in a rod shape, and its longitudinal direction is oriented in the direction of the tunnel width.

[0043] The heater 41 is attached to a support frame 42 provided on the bottom surface of the running section 91 on the pier 90. Specifically, the heater 41 is attached to a pair of support frames 42, the longitudinal ends of which are spaced apart in the tunnel width direction. The pair of support frames 42 are erected between a plurality of transverse girders 91A that constitute the running section 91 of the pier 90 and are spaced apart in the tunnel length direction.

[0044] Multiple heaters 41 are provided at intervals in the tunnel width direction and the tunnel length direction. Therefore, the heaters 41 can heat the entire surface of the invert concrete 101 below the pier 90.

[0045] In the lower construction section 12, the sheet 21 is positioned above the nozzle in the water supply section 30 and the heater 41 in the heating section 40. Alternatively, the sheet 21 is positioned at the same height as or below the water supply nozzle 31 and heater 41, with openings formed to expose them downwards, corresponding to the positions of the water supply nozzle 31 and heater 41. This allows the sheet 21 to maintain the wet state of the invert concrete 101 due to water sprayed from the water supply nozzle 31 and the temperature state of the invert concrete 101 heated by the heater 41.

[0046] (Tunnel construction methods) Figures 9A to 9H are front views illustrating the construction method of invert concrete. The following describes a method for constructing invert concrete 101 using the hardening accelerator 10 of this embodiment.

[0047] Figure 9A shows the tunnel before the invert concrete 101 is constructed. In Figure 9A, the invert concrete 101 to be constructed is indicated by a dashed line. As shown in Figure 9B, first, a pier 90 is installed on one side in the tunnel width direction to allow vehicles 102 to travel on it. In this state, the ground on the other side in the tunnel width direction is excavated by the excavation device 103 within the range of a predetermined construction section S1 (see Figure 2). In Figure 9B, the area to be excavated is indicated by hatching.

[0048] Next, as shown in Figure 9C, the pier 90 is moved to the other side in the tunnel width direction, and the ground on one side in the tunnel width direction is excavated by the excavation device 103 within the range of a predetermined construction section S1. Subsequently, as shown in Figure 9D, formwork 104 for the invert concrete 101 is installed at the excavated area. The hardening accelerator 10 of this embodiment is then attached to the pier 90. However, the hardening accelerator 10 may be attached to the pier 90 beforehand.

[0049] Subsequently, as shown in Figure 9E, invert concrete 101 is poured into the formwork 104. This pouring process includes pouring ready-mix concrete, compaction, and surface finishing with a trowel. When setting up the formwork 104 or pouring the invert concrete 101, the pier 90 is moved left or right as needed to facilitate the work. Then, as shown in Figure 9F, the expansion member 51 of one of the lateral construction sections 11 of the hardening accelerator 10 installed on the pier 90 is extended in the tunnel width direction. In the example shown in Figure 9F, since the pier 90 is located on one side in the tunnel width direction, the expansion member 51 of the lateral construction section 11 located on the other side of the tunnel width direction relative to the pier 90 is extended. Then, the sheet 21 of the covering section 20 supported by this expansion member 51 covers the top of the invert concrete 101, and the water supply section 30 and heating section 40 are activated. At the same time, the water supply section 30 and heating section 40 in the lower construction section 12 are also activated. This allows the moisture level and temperature of the invert concrete 101 to be adjusted and maintained, thereby accelerating the hardening of the invert concrete 101.

[0050] Furthermore, for the lateral construction section 11 located on one side in the tunnel width direction (the right side in Figure 9F), the sheet 21 attached to the upper part of the expansion member 51, with the expansion member 51 in a contracted state, covers the area above the invert concrete 101 located on one side in the tunnel width direction from the pier 90. For this lateral construction section 11, the water supply section 30 and heating section 40 may or may not be activated. This is because the area cured using this lateral construction section 11 is small, and the moisture level and temperature of this area can be adjusted by the water supply section 30 and heating section 40 in the lower construction section 12.

[0051] As shown in Figures 9G and 9H, once the invert concrete 101 has finished hardening, the pier 90 is moved in the tunnel width direction as needed, and the excavation device 103 is used to backfill the area above the invert concrete 101 with soil 106.

[0052] Once the construction of the invert concrete 101 is completed in one construction section S1, the ground is excavated in the next construction section S1 (excavation section), as shown in Figures 2 and 3, and the above process is repeated.

[0053] As described above, the hardening acceleration device 10 for invert concrete 101 allows for curing of the invert concrete 101 that has been poured over the entire width of the tunnel. Therefore, compared to, for example, constructing the invert concrete 101 one side at a time in the width of the tunnel, the quality of the invert concrete 101 can be improved and the construction period can be shortened.

[0054] The hardening accelerator 10 is equipped with an expandable member 51 that expands and contracts in the tunnel width direction, and this expandable member 51 is equipped with a covering section 20, a water supply section 30, and a heating section 40, which are curing means. Therefore, after the invert concrete 101 is poured, the curing means 20, 30, and 40 can be easily positioned above the invert concrete 101 by extending the expandable member 51 upwards.

[0055] Furthermore, the covering portion 20 of the curing accelerator 10 is equipped with a winding roll 22 for winding up the sheet 21, so the sheet 21 can be pulled out or wound up in accordance with the expansion and contraction of the expandable member 51.

[0056] The hardening accelerator 10 in the above embodiment is attached to a pier 90 (structure), which is a structure installed above the invert concrete 101. Therefore, there is no need to place the hardening accelerator 10 on the ground inside the tunnel or to support the curing device using the tunnel's side walls, etc. As a result, the hardening accelerator 10 can be installed without securing space for the hardening accelerator 10 inside the tunnel 100 or constructing support brackets, etc., on the tunnel's side walls.

[0057] The expansion member 51 of the lateral construction section 11 in the hardening accelerator 10 is attached to the pier 90 and expands and contracts in the tunnel width direction, so that the curing means, the covering section 20, the water supply section 30, and the heating section 40, can be easily positioned above the area of ​​the invert concrete 101 that is not covered by the pier 90. Furthermore, since the expansion member 51 is positioned on both sides of the pier 90 in the tunnel width direction, the curing means, the covering section 20, the water supply section 30, and the heating section 40, can be easily positioned above the invert concrete 101 regardless of whether the pier 90 is moved to one side or the other side in the tunnel width direction.

[0058] Since the lower construction section 12 of the hardening accelerator 10 is provided on the underside of the pier 90, the covering section 20, water supply section 30, and heating section 40, which are curing means, can be placed over the area of ​​invert concrete covered by the pier 90, and curing can be performed.

[0059] The present invention is not limited to the embodiments described above, and can be modified as appropriate within the scope of the invention as described in the claims.

[0060] For example, in the above embodiment, the expansion member 51 may be supported from below or above at its outer end in the tunnel width direction, or at multiple locations in the tunnel width direction including the outer end. For example, the expansion member 51 may be supported from below by providing a leg extending downward from the expansion member 51 and placing this leg on the upper surface of the invert concrete 101.

[0061] In the above embodiment, the expandable member 51 was configured to expand and contract in the tunnel width direction, but it may also be configured to expand and contract in the tunnel extension direction, or in an inclined direction having components in both the tunnel width direction and the tunnel extension direction. Furthermore, although the expandable member 51 had a pantograph structure in the above embodiment, it is not limited to this and may have other expandable structures such as a telescopic structure (slide structure).

[0062] The hardening accelerator 10 of the above embodiment included a covering section 20 (sheet 21), a water supply section 30 (water supply nozzle 31), and a heating section 40 (heater 41) as curing means, but it is sufficient to have at least one of these. In addition, other conventionally known configurations can be used as curing means. For example, means for supplying steam to the upper surface of the invert concrete 101, or means for directly contacting the water-retentive sheet 21 with the upper surface of the invert concrete 101 can be used.

[0063] In the above embodiment, the hardening accelerator 10 (lower construction section 12) was attached to the underside of the pier 90, but it may also be attached to a structure other than the pier 90, for example, to the underside of a work platform positioned above the invert concrete 101.

[0064] In the above embodiment, the sheet 21 used as a curing means had a length that extended over the entire construction section S1 in the direction of tunnel extension, but it may be divided into multiple sections in the direction of tunnel extension. [Explanation of Symbols]

[0065] 10: Hardening accelerator 20: Covering (protection method) 30: Water supply section (curing means) 40: Heating section (curing means) 90: Pier 100: Tunnel 101: Invert Concrete

Claims

1. A hardening accelerator for curing and accelerating the hardening of invert concrete poured into the lower part of a tunnel, An invert concrete hardening accelerator, which is attached to the underside of a structure installed at a distance above the invert concrete and is equipped with a curing means for curing the invert concrete.

2. The invert concrete hardening accelerator according to claim 1, wherein the curing means includes at least one of a water supply unit for supplying water to the surface of the invert concrete and a heating unit for heating the invert concrete.

3. The invert concrete hardening accelerator according to claim 1 or 2, wherein the curing means includes a covering portion having a sheet that covers the invert concrete from above.

4. The invert concrete hardening accelerator according to claim 1 or 2, wherein the structure is a pier that straddles the invert concrete in the direction of tunnel extension.

5. The invert concrete hardening accelerator according to claim 4, further comprising other curing means attached to the left and right sides of the pier.

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