JP7520346B2 - Manhole rehabilitation structure and construction method - Google Patents

Description

The present invention relates to a manhole rehabilitation structure and its construction method, and in particular to a manhole rehabilitation structure in which a cylindrical rehabilitation manhole is installed inside an existing buried manhole, and its construction method.

The average sewerage coverage rate in Japan is about 79%, and in urban areas it is close to 100%. Sewer pipes deteriorate with years of use, and their useful life is generally considered to be about 50 years. The total length of sewer pipes is over 470,000 km, and the number of manholes associated with it is about 8 to 10 million. In recent years, the number of manholes that have exceeded their useful life has been increasing, and repairs due to deterioration are urgently needed. Generally, manholes are installed in the ground as concrete cylinders of a certain thickness, with the top of the cylinder opening at the ground surface.

A method using backfill material is generally known as a method for rehabilitating such manholes. In this method, as described in Patent Document 1, a cylindrical repair material is assembled along the inner circumferential surface of an existing cylindrical manhole, and a spacer is placed between the outer circumferential surface of the repair material and the inner circumferential surface of the existing manhole to form a gap. A backfill material such as mortar is injected into this gap and hardened, thereby integrating the existing manhole with a rehabilitating manhole made of the backfill material and repair material. This method is a so-called composite manhole rehabilitation method in which the load-bearing capacity is ensured by integrating the rehabilitating manhole with the existing manhole.

Patent Document 2 also describes another construction method that uses a lining material in which a photocurable resin composition is impregnated into a glass fiber substrate without using a backfill material. In this construction method, a cylindrical uncured lining material with an opening sealed by a sealing device is first introduced in a folded state into the interior of an existing manhole. Air is then introduced into the interior of the lining material from the air inlet of the sealing device to expand it, and the lining material is compressed against the inner wall of the existing manhole by air pressure. In this state, light is irradiated from a light irradiation device that has been previously introduced into the interior of the bag-shaped lining material, and a photocured lining material, i.e., a manhole for rehabilitation, is formed on the inner surface of the existing manhole.

The advantage of manhole rehabilitation structures using lining materials is that, since the hardened lining material is generally stronger than the backfill material, when the strength of the existing manhole cannot be expected, the load-bearing capacity required of the manhole can be ensured using only the rehabilitation manhole. In other words, this method is a self-supporting manhole rehabilitation method.

JP 2001-090173 A JP 2014-076592 A

Vertical loads acting from above on the lid that covers the top opening of a manhole, such as vertical loads received from people or vehicles passing over the manhole, act on the top surface of the manhole via a lid support frame that is installed at the top of the manhole to secure the lid to the manhole, and an annular adjustment ring that is stacked on the top surface of the manhole to adjust the height of the manhole.

Generally, the inner diameter of the lid receiving frame and adjustment ring is set to the same size as the inner diameter of the standardized upper opening of an existing manhole, and when a new rehabilitation manhole is installed inside an existing manhole, the outer diameter of the rehabilitation manhole will be smaller than the inner diameter of the existing lid receiving frame and the inner diameter of the existing adjustment ring.

Therefore, if an existing lid receiving frame or adjustment ring is used, the vertical load acting on the lid is not transmitted to the rehabilitation manhole, and the load-bearing capacity of the newly constructed rehabilitation manhole cannot be fully utilized. In addition, if an attempt is made to solve this problem by excavating the road surface and removing the existing adjustment ring and lid receiving frame from the existing manhole, and then placing a new load transmitting body between the rehabilitation manhole and the adjustment ring, it will be necessary to return the adjustment ring and lid receiving frame, which will lengthen the construction period and increase construction costs.

The present invention was made in consideration of the above problems, and its purpose is to provide a manhole rehabilitation structure in which a rehabilitation manhole is installed inside an existing manhole, and a construction method thereof that can transmit the vertical load acting on the cover from above to the rehabilitation manhole while shortening the construction period.

In order to achieve the above object, the manhole rehabilitation structure according to the present invention comprises:
An existing adjustment ring for height adjustment placed on an existing manhole;
A manhole rehabilitation structure comprising: a rehabilitation manhole installed inside the existing manhole,
An annular cutout portion formed on the inner circumferential surface of the existing adjustment ring and/or the inner circumferential surface of the upper end portion of the existing manhole, the annular cutout portion extending around the entire circumference of the existing adjustment ring and/or the existing manhole;
and an annular load transfer structure that is fitted into the annular cutout and overlaps with an upper end surface of the rehabilitation manhole,
The load transfer structure is characterized in that it is composed of a plurality of load transfer pieces divided in the circumferential direction.

According to this configuration, when a load is applied to the cover by a person or vehicle passing over the cover, the load is transmitted from the cover through the existing adjustment ring to the load transmission structure, and then to the upper end face of the manhole to be rehabilitated, which is located below the load transmission structure. As a result, even if the existing manhole can no longer withstand the required vertical load due to deterioration, the load received by the cover can be transmitted to the newly constructed manhole to be rehabilitated, and the load-bearing capacity of the manhole to be rehabilitated can be fully utilized to maintain the performance of the manhole.
The load transfer structure is composed of a plurality of load transfer pieces divided in the circumferential direction, and each load transfer piece is inserted into the annular cutout of the existing adjustment ring, so that the annular load transfer structure can be fitted and installed in the annular cutout. Furthermore, the annular cutout of the existing adjustment ring can be formed, for example, by cutting a part of the existing adjustment ring, and there is no need to excavate the road surface to remove the existing adjustment ring or to backfill the existing adjustment ring and restore the road surface, so that the construction period can be shortened and the construction costs can be reduced.

The manhole rehabilitation structure according to claim 2 of the present invention is the manhole rehabilitation structure according to claim 1,
Each load transfer piece is
A plate-shaped main body portion overlapping the upper end surface of the rehabilitation manhole, and a lower protruding piece protruding from the lower surface of the main body portion and abutting against the inner circumferential surface of the rehabilitation manhole,
The manhole is further characterized by being provided with an annular member that presses the lower protruding pieces of each load transmission piece against the inner circumferential surface of the manhole from the inside of the manhole.

With this configuration, each load transmission piece is pressed and fixed to the inner circumferential surface of the rehabilitation manhole by the annular member, so that the installation state of each load transmission piece relative to the rehabilitation manhole can be stabilized. This allows the vertical load acting on the cover body to be properly transmitted to the upper end surface of the rehabilitation manhole via the existing adjustment ring and each load transmission piece.

The manhole rehabilitation structure according to claim 3 of the present invention is the manhole rehabilitation structure according to claim 1,
Each load transfer piece is
It is characterized by having a plate-shaped main body portion that overlaps the upper end surface of the rehabilitation manhole, and an upper protruding piece that protrudes from the upper surface of the main body portion and directly or indirectly abuts against the inner surface of the existing adjustment ring stacked on the main body portion.

With this configuration, if the existing manhole becomes unable to withstand the vertical load from above due to deterioration, the load transmission piece will be subjected to a force that causes it to warp towards the existing manhole due to the vertical load transmitted from the cover body via the load transmission piece to the existing manhole, but the upper protruding piece on the load transmission piece directly or indirectly abuts against the inner peripheral surface of the existing adjustment ring, preventing the load transmission piece from warping. This allows the vertical load from above acting on the cover body to be properly transmitted to the upper end surface of the undeteriorated rehabilitated manhole.

The manhole rehabilitation structure according to claim 4 of the present invention is the manhole rehabilitation structure according to claim 3,
The present invention is characterized in that it includes an annular body interposed between the upper protruding piece of each load transmission piece and the inner peripheral surface of the existing adjustment ring.

According to this configuration, when a force that causes the load transmission piece to warp toward the existing manhole is applied to the load transmission piece due to a vertical load transmitted from the cover body to the existing manhole via the load transmission piece, the upper protruding piece provided on the load transmission piece indirectly abuts against the inner peripheral surface of the existing adjustment ring via the annular body, thereby preventing the load transmission piece from warping. In addition, the force acting on the annular body from the upper protruding piece can be dispersed in the circumferential direction, improving the load transmission performance and improving the durability of the load transmission structure against vertical loads.

In addition, a manhole rehabilitation structure according to a fifth aspect of the present invention is a manhole rehabilitation structure according to any one of the second to fourth aspects,
The present invention is characterized in that a gap between the main body portions of adjacent load transfer pieces is filled with a filler material.

According to this configuration, by filling the gaps between the main body parts of adjacent load transfer pieces inserted into the annular cutouts with a filler, the installation state of each load transfer piece relative to the rehabilitation manhole can be stabilized, thereby improving the durability of the load transfer structure against vertical loads.

The present invention also provides a construction method for a manhole rehabilitation structure according to any one of claims 1 to 5,
A process of cutting the inner circumferential surface of the existing adjustment ring and/or the inner circumferential surface of the upper end portion of the existing manhole around the entire circumference to form the annular notch portion;
and a step of inserting the plurality of load transfer pieces into the annular cutout portion to install the load transfer structure.

According to this configuration, the inner peripheral surface of the existing adjustment ring is cut to form an annular cutout, and multiple load transfer pieces are inserted into the annular cutout, allowing the annular load transfer structure to be fitted and installed in the annular cutout. This eliminates the need to excavate the road surface to install the load transfer structure, and shortens the construction period.

According to the manhole rehabilitation structure and construction method of the present invention, the load acting on the cover can be transmitted to the rehabilitation manhole via the existing adjustment ring and the load transmission structure. The load transmission structure is composed of multiple load transmission pieces, and the annular load transmission structure can be installed by fitting each load transmission piece into the annular recess formed between the annular cutout of the existing adjustment ring and the upper end faces of both the existing and rehabilitation manholes. Since the load transmission structure can be installed without excavating the road surface, the construction period can be shortened and construction costs can be reduced.

1 is a cross-sectional view showing a schematic diagram of a manhole rehabilitation structure according to a first embodiment of the present invention. FIG. This is an enlarged cross-sectional view of a main part of a manhole rehabilitation structure. FIG. FIG. FIG. 2 is a cross-sectional view showing a schematic diagram of a manhole rehabilitation structure according to a second embodiment of the present invention. This is an enlarged cross-sectional view of a main part of a manhole rehabilitation structure. FIG. FIG. 4 is a plan view of the load transfer structure and the annular member. 9 is a cross-sectional view of the portion shown by line AA in FIG. 8, illustrating the state of opposing surfaces of adjacent load transmitting pieces. FIG. 11A and 11B are diagrams illustrating other examples of the annular member. FIG. 6 is a schematic cross-sectional view similar to FIG. 5, illustrating a construction method for a manhole rehabilitation structure. FIG. 7 is an explanatory diagram of a construction method for a manhole rehabilitation structure, and is an enlarged cross-sectional view of a main portion similar to FIG. 6. 13 is a diagram for explaining a construction method of a manhole rehabilitation structure, and is a cross-sectional view of the area indicated by line B-B in FIG. 12. FIG. 7 is an explanatory diagram of a construction method for a manhole rehabilitation structure, and is an enlarged cross-sectional view of a main portion similar to FIG. 6. FIG. 11 is an enlarged cross-sectional view of a main portion of a manhole rehabilitation structure according to a third embodiment of the present invention. FIG. 2 is a plan view of the load transfer structure and the annular body.

(First embodiment)
Fig. 1 is a cross-sectional view showing a manhole rehabilitation structure according to a first embodiment of the present invention, and Fig. 2 is an enlarged cross-sectional view showing a main part of the manhole rehabilitation structure shown in Fig. 1. Note that the drawings used to explain the present invention show the main parts with emphasis, and do not show the actual dimensional ratios.

The manhole rehabilitation structure 10 includes an existing manhole 20 buried in the ground, a rehabilitation lining material 12 that is a manhole for rehabilitating the existing manhole 20, an adjustment ring (existing adjustment ring) 14 and adjustment mortar 17 that are height adjustment members for adjusting the height of the manhole, a lid receiving frame 18 (hereinafter simply referred to as the "receiving frame 18"), and a lid 19. The manhole rehabilitation structure 10 also includes an annular load transfer structure 30 installed between the receiving frame 18 and the rehabilitation lining material 12. As shown in Figures 3 and 4, the load transfer structure 30 is composed of multiple load transfer pieces 40 divided in the circumferential direction, and is formed into a ring shape as a whole by connecting each load transfer piece 40. In this embodiment, three load transfer pieces 40A, 40B, and 40C constitute one annular load transfer structure 30.

The existing manhole 20 is a manhole to be rehabilitated, and is formed in a cylindrical shape with a bottom having a predetermined thickness. Such existing manholes 20 are arranged at a fixed interval with respect to the sewer pipes buried in the ground, and are attached with the ends of the sewer pipes 71, 72 inserted into the mounting holes 24, 25 formed in the lower wall surface of the existing manhole 20. The upper opening of the existing manhole 20 is usually set to a diameter of 600 mm so that a person can enter. The existing manhole 20 of this embodiment is made of concrete, for example, and has a base 21 that serves as a foundation, an invert part 22 that is installed on the base 21 and forms the bottom surface of the manhole and has a U-shaped groove, a straight wall part 23A that extends cylindrically upward (toward the ground) from the base 21, and an inclined wall part 23B that is located above the straight wall part 23A and has a wall surface that is inclined so that the inner diameter and outer diameter gradually become smaller toward the upper side.

The rehabilitation lining material 12 is installed inside the existing manhole 20, has a predetermined thickness, and is formed into a bottomed or bottomless cylindrical shape that conforms to the shape of the existing manhole 20. In this embodiment of the rehabilitation lining material 12, the rehabilitation lining material 12 is bottomless cylindrical and has a straight wall cylindrical portion 13A and a slant wall cylindrical portion 13B that are adapted to the straight wall portion 21 and the slant wall portion 22, respectively, of the existing manhole 20, and the straight wall cylindrical portion 13A has sewer pipe mounting holes 28, 29 formed therein that are adapted to the mounting holes 24, 25 of the existing manhole 20.

In this embodiment, the position of the upper end of the rehabilitation lining material 12 coincides with the position of the upper end of the existing manhole 20 in the vertical direction, and the upper end surface 12a of the rehabilitation lining material 12 and the upper end surface 20a of the existing manhole 20 are formed to be almost flush with each other. In addition, each upper end surface 12a, 20a is formed in a circular shape.

As the material for the rehabilitation lining material 12, for example, an impregnated base material made of fibers or the like (for example, a fiber base material such as glass fiber or polyester fiber, or a nonwoven fabric such as felt) impregnated with a photocurable resin composition and/or a thermosetting resin composition can be used. In this embodiment, an impregnated base material made of glass fiber is impregnated with a photocurable resin composition. The photocurable resin composition can contain, for example, a polymerizable resin, a polymerizable unsaturated monomer, and a photopolymerization initiator, and the polymerizable resin can be an unsaturated polyester, vinyl ester resin, or the like. As the photopolymerization initiator, for example, an ultraviolet polymerization initiator that promotes the polymerization of the resin by ultraviolet light can be used, but it is preferable to use one that can promote the polymerization of the resin by the action of both ultraviolet light and visible light. Such a rehabilitation lining material 12 has flexibility in an uncured state in which the hardening resin composition is not cured, and is formed into a bottomed or bottomless cylindrical shape that is adapted to the shape of the existing manhole 20 so that it has an outer diameter corresponding to the inner diameter of the existing manhole 20 after curing.

The rehabilitation lining material 12 can also be configured to include an inner film and an outer film that protect the inner and outer surfaces, respectively. The inner film is transparent to light from a light irradiation device that irradiates light onto the rehabilitation lining material 12, and it is preferable to use a light-shielding film for the outer film so that the light irradiated from the light irradiation device does not penetrate to the outside of the rehabilitation lining material 12 and is used for the photocuring reaction.

The rehabilitation lining material 12 of this embodiment has a free-standing manhole structure that has the load-bearing performance required of a manhole without relying on the existing manhole 20, and in this embodiment, it has a free-standing structure that can withstand a predetermined vertical load (e.g., a vertical load of 20 tons or more) by itself. The thickness of the rehabilitation lining material 12 can be 5 mm to 30 mm, and more preferably in the range of 10 mm to 20 mm. This thickness can be set appropriately depending on the inner diameter of the existing manhole 20 to be rehabilitated, etc.

The adjustment ring 14 and adjustment mortar 17 are interposed between the cover 19 that closes the upper opening of the existing manhole 20 and the existing manhole 20, and are components for adjusting the height of the existing manhole 20 relative to the ground G and the receiving frame 18. The adjustment ring 14 and adjustment mortar 17 are existing components that were installed on the existing manhole 20 before the rehabilitation lining material 12 was installed, and are placed on the upper end surface 20a of the existing manhole 20 in that order, with the adjustment ring 14 and adjustment mortar 17 forming a circular ring shape when viewed from above.

The adjustment ring 14 is made of concrete, for example, and is placed on the existing manhole 20. As described above, the adjustment mortar 17 is provided on the adjustment ring 14, and is formed by filling the gap between the adjustment ring 14 and the receiving frame 18 with mortar in a ring shape. In this embodiment, the thickness of the adjustment ring 14 (i.e., the height in the vertical direction when installed) is greater than the thickness of the adjustment mortar 17. Note that multiple adjustment rings 14 can be installed depending on the required height. The inner and outer diameters of the adjustment ring 14 and the adjustment mortar 17 are approximately the same as the inner and outer diameters of the upper end surface 20a of the existing manhole 20, respectively.

The adjustment ring 14 has an annular cutout 15 on its inner circumferential surface, which is cut out over the entire circumference. The annular cutout 15 is a portion where the inner circumferential surface 14a of the adjustment ring 14 is concave radially outward over the circumferential direction. The load transfer structure 30 is fitted into the annular cutout 15. As described below, in this embodiment, the load transfer structure 30 is fitted into an annular recess 15A formed by the annular cutout 15, the upper end surface 20a of the existing manhole 20, and the upper end surface 12a of the rehabilitation manhole 12.

The receiving frame 18 has a ring-shaped installation section 18A and a lid body accommodating section 18B formed at the upper opening edge of the installation section 18A and accommodating the lid body 19. The installation section 18A is a section that is placed on the upper end surface 20a of the existing manhole 20, and in this embodiment, is installed on the existing manhole 20 via the load transfer structure 30, the adjustment ring 14, and the adjustment mortar 17. The receiving frame 18, the adjustment mortar 17, and the adjustment ring 14 are fixed to the existing manhole 20 by a plurality of anchor bolts 11 that extend through them to the existing manhole 20.

The cover 19 is attached to the existing manhole 20 via the receiving frame 18 and closes the upper opening of the existing manhole 20. It is formed in a disk shape.

The load transfer structure 30 transfers an external force acting on the lid body 19, specifically, a vertical load F acting on the lid body 19 from above, to the rehabilitation lining material 12. The load transfer structure 30 transfers the vertical load transferred via the lid body 19 to the upper end surface 12a of the rehabilitation lining material 12.
The load transfer structure 30 is an annular member that is installed so as to overlap at least the upper end surface 12a of the rehabilitation lining material 12, among the upper end surface 20a of the existing manhole 20 and the upper end surface 12a of the rehabilitation lining material 12. In this embodiment, it overlaps both upper end surfaces 20a, 12a. In this embodiment, the load transfer structure 30 is formed in a circular ring shape, but the shape is not limited to this, and it may be any shape that matches the planar shape of the upper end 20a of the existing manhole 20. For example, if the planar shape of the upper end 20a is a square ring, the load transfer structure 30 can be a square ring. The load transfer structure 30 can be manufactured from, for example, concrete, iron such as cast iron or steel, other metals, resin such as fiber-reinforced resin, or a combination of these materials.

As shown in FIG. 3, the load transfer structure 30 has a structure body 32 formed in the shape of a circular ring plate, and an upper annular protrusion 38 protruding from the upper surface 32a of the structure body 32 (i.e., the surface facing upward when installed). The structure body 32 is the part that is inserted into the annular recess 15A, and the upper annular protrusion 38 is formed so as to protrude upward from the inner peripheral edge of the upper surface 32a of the structure body 32. The lower surface 32b of the structure body 32 is formed as a flat surface.

The thickness of the structure body 32 of the load transfer structure 30 is set to be smaller than the thickness of the adjustment ring 14, and can be, for example, 5 mm to 55 mm, preferably 5 mm to 35 mm, and more preferably 5 mm to 15 mm. The outer diameter D1 of the structure body 32 is set to be larger than the inner diameter of the upper end of the existing manhole 20 and smaller than the outer diameter of the adjustment ring 14 (which is approximately equal to the outer diameter of the upper end of the existing manhole 20). The inner diameter D2 of the structure body 32 is set to be smaller than the inner diameter of the upper end of the rehabilitation lining material 12. When installed, the load transfer structure 30 is arranged concentrically with the upper opening of the existing manhole 20 when viewed from above.

As shown in Figures 2 and 3, the load transfer structure 30 is composed of multiple load transfer pieces 40. In this embodiment, the load transfer structure 30 is composed of three load transfer pieces 40A, 40B, and 40C. It is preferable that the load transfer pieces 40A, 40B, and 40C are set so that their circumferential lengths are approximately equal. The number of load transfer pieces 40 is not limited to three, and may be two or more, but it is preferable to set it to three to five from the viewpoint of ease of installation, etc.

Each of the load transmission pieces 40A, 40B, and 40C has a main body portion 42 constituting the structure body 32 and an upper protruding piece 47 constituting the upper annular protruding portion 34. The main body portion 42 is formed in a substantially arc-shaped plate shape by dividing the structure body 32 in the circumferential direction. The upper protruding piece 47 is a portion that protrudes upward from the top surface of the main body portion 42 in the installed state, protrudes almost perpendicularly from the inner peripheral edge of the main body portion 42, and is formed in an arc shape along this inner peripheral edge. As shown in FIG. 2, each load transmission piece 40 is installed so that the upper protruding piece 47 directly abuts against the inner peripheral surface 14a of the adjustment ring 14.

As shown in FIG. 4, one of the three load transfer pieces 40A, 40B, and 40C is formed so that the side edges 41a and 41b at both ends of the circumferential direction of the main body 42 of the load transfer piece 40C extend parallel to each other. In addition, the side edges 41c and 41d at one end of the circumferential direction of the two adjacent load transfer pieces 40A and 40B are formed in a straight line along the side edges 41a and 41b in accordance with the side edges 41a and 41b of the load transfer piece 40C. In this way, when there are three or more load transfer pieces 40 constituting the load transfer structure 30, it is preferable that the side edges 41a and 41b of at least one load transfer piece 40C are formed parallel to each other, so that the load transfer pieces 40A, 40B, and 40C can be easily inserted sequentially from the radial inside into the annular cutout portion 15 of the adjustment ring 14, as described later.

The load transfer structure 30 is formed by assembling the load transfer pieces 40A, 40B, and 40C into a ring shape. Gaps may be formed between the load transfer pieces 40A, 40B, and 40C, and these gaps may be filled by injecting a filler material.

Also, as shown by the virtual lines in FIG. 3, adjacent load transmission pieces 40 may be connected by a connecting member 60. The connecting member 60 shown in FIG. 3 may be composed of an arc-shaped connecting piece 61 arranged across two adjacent load transmission pieces, and fixing members 62, 63 such as bolts that fix the connecting piece 61 to each load transmission piece. An adhesive may be applied to the surface of the connecting piece 61 facing the load transmission piece 40. In this way, by connecting adjacent load transmission pieces 40 to each other and maintaining the annular state, the installation state of each load transmission piece can be stabilized.

As shown in FIG. 1, in the above-mentioned manhole rehabilitation structure 10, when a load F is applied to the cover 19 by a person or vehicle passing over the cover 19, the load F is transmitted from the cover 19 to the load transmission structure 30 via the receiving frame 18, the adjustment mortar 17, and the adjustment ring 17, and is transmitted to the upper end surface 20a of the existing manhole 20 and the upper end surface 12a of the rehabilitation lining material 12 below the structure body 32 of the load transmission structure 30. In this way, by providing the load transmission structure 30 between the cover 19 and the rehabilitation lining material 12, the load received by the cover 19 can be transmitted to the new rehabilitation lining material 12. As a result, even if the existing manhole 20 cannot withstand the required vertical load F due to aging, the load received by the cover 19 can be transmitted to the new rehabilitation lining material 12, making full use of the load-bearing performance of the rehabilitation lining material 12, and maintaining the performance of the manhole.

The load transfer structure 30 is composed of multiple load transfer pieces 40A, 40B, 40C divided in the circumferential direction, and the ring-shaped load transfer structure 30 can be installed by inserting each of the load transfer pieces 40A, 40B, 40C into the ring-shaped cutout 15. The ring-shaped cutout 15 can be formed, for example, by cutting a part of the adjustment ring 14 from the inside, and there is no need to excavate the road surface of the ground where the existing manhole 20 is installed (i.e., ground G in FIG. 1) to remove the adjustment ring 14 or to backfill the adjustment ring 14 to restore the road surface, so the construction period can be shortened, and therefore the construction costs can be reduced.

In addition, by providing each load transmission piece 40 with an upper protruding piece 47, even if the existing manhole 20 becomes unable to withstand the vertical load F from above due to aging and a portion of the upper end surface 20a of the existing manhole 20 collapses, this upper protruding piece 47 abuts against the inner surface 14a of the adjustment ring 14, preventing the load transmission piece 40 from warping toward the existing manhole 20. This increases the durability of the load transmission structure 30 against the vertical load F.

Second Embodiment
Next, a second embodiment of the manhole rehabilitation structure 10 will be described with reference to Figures 5 to 8. Figure 5 is a cross-sectional view similar to Figure 1, which shows a schematic diagram of the second embodiment of the manhole rehabilitation structure 10, and the same reference numerals are used for parts corresponding to those in the first embodiment. In the second embodiment described below, detailed description of the same configuration as in the first embodiment will be omitted. The manhole rehabilitation structure 10 of this embodiment further includes an annular member 50 that fixes the load transfer structure 30 to the rehabilitation lining material 12.

In this embodiment, as shown in FIG. 7, the load transfer structure 30 has a structure body 32 formed in a circular plate shape and a lower annular protrusion 34 protruding from the lower surface 32b of the structure body 32. As shown in FIG. 6, the structure body 32 is a portion that is inserted into the annular cutout portion 15 formed in the adjustment ring 14. In this embodiment, the structure body 32 is inserted into the annular recess 15A formed between the existing manhole 20 and the rehabilitation manhole 12 and the adjustment ring 14. The lower annular protrusion 34 protrudes downward from the inner peripheral edge of the lower surface 32b of the structure body 32. The upper surface 32a of the structure body 32 is formed as a flat surface.

The lower annular protrusion 34, together with the annular member 50, is a portion for fixing the load transmission structure 30 to the rehabilitation lining material 12. The outer diameter φ of the lower annular protrusion 34 is preferably set to correspond to the inner diameter of the upper end of the rehabilitation lining material 12, and in the example shown in FIG. 2, the outer diameter φ of the lower annular protrusion 34 is set to be approximately the same as the inner diameter of the upper end of the rehabilitation lining material 12 so that the outer peripheral surface of the lower annular protrusion 34 abuts against the inner peripheral surface of the rehabilitation lining material 12 over the circumferential direction when installed.

Figure 8 is a plan view of the load transfer structure 30 and the annular member 50 installed on its inner periphery, viewed from above. As shown in Figures 7 and 8, the load transfer structure 30 is composed of multiple load transfer pieces 40A, 40B, and 40C that are divided in the circumferential direction.

Each of the load transmission pieces 40A, 40B, 40C has a main body portion 42 that constitutes the structure body 32, and a lower protruding piece 44 that constitutes the lower annular protruding portion 34. The main body portion 42 is formed in a generally arc-shaped plate shape by dividing the structure body 32 in the circumferential direction. The lower protruding piece 44 is a portion that protrudes downward from the underside of the main body portion 42 in the installed state, protrudes almost perpendicularly from the inner peripheral edge of the main body portion 42, and is formed in an arc shape that follows this inner peripheral edge.

As shown by the dashed lines in FIG. 8, the corners of the main body 42 of each of the load transfer pieces 40A, 40B, and 40C may be chamfered as necessary. In FIG. 8, as an example, the chamfered portion 46a of the first load transfer piece 40A, the chamfered portion 46b of the second load transfer piece 40B, and the two chamfered portions 46c and 46d of the third load transfer piece 40C are each shown by dashed lines. By chamfering the corners in this manner, it is possible to prevent the corners from hitting each other when inserting the load transfer piece 40 into the annular recess 15A, making it easier to insert. This chamfering structure can also be applied to each load transfer piece 40 of the first embodiment.

The load transfer structure 30 is formed by assembling the load transfer pieces 40A, 40B, and 40C into a ring shape. Gaps may be formed between the load transfer pieces 40A, 40B, and 40C, but as described below, these gaps may be filled by injecting a filler material 48 into them.

Figure 9 is a diagram illustrating the state of the opposing surfaces of the main body 42 of adjacent load transmission pieces 40A, 40B, and is a cross-sectional view of the area indicated by line A-A in Figure 8. Note that Figures 9(a) to (c) each show a different embodiment.

As shown in the example in FIG. 9(a), the opposing surfaces 43A, 43B of the load transfer pieces 40A, 40B can be planar along the axial direction of the load transfer structure 30. The gap S between the opposing surfaces 43A, 43B is filled with a filler 48. The filler 48 can be a material that is liquid when injected and hardens over time, such as mortar.

In another embodiment shown in FIG. 9(b), the opposing surfaces 43A, 43B of adjacent load transfer pieces 40A, 40B are inclined with respect to the axial direction of the load transfer structure 30. For example, when the load transfer structure 30 includes two load transfer pieces 40, the opposing surfaces of adjacent load transfer pieces 40 are inclined as in this embodiment, so that each load transfer piece 40 can be inserted into the annular recess 15A.

In yet another embodiment shown in FIG. 9(c), the opposing surfaces 43A, 43B of adjacent load transfer pieces 40A, 40B have a roughly triangular concave-convex cross section. One of the opposing surfaces 43A has a hole 45 extending in the radial direction of the load transfer structure 30. In the illustrated example, the hole 45 is formed at the apex of the triangular cross section of the opposing surface 43A that forms a concave triangular cross section. By forming the hole 45 in this way, the filler 48 can be easily injected from this hole 45 into the gap between each of the load transfer pieces 40A, 40B.

Although not shown, the opposing surfaces of the body parts 42 of adjacent load transfer pieces 40A, 40C and the opposing surfaces of the body parts 42 of adjacent load transfer pieces 40B, 40C can also be inclined or filled with filler 48 as in the example shown in Figures 9(a) to (c). Also, in the first embodiment, it is possible to inject filler 48 between adjacent load transfer pieces 40.

As shown in Figures 5 and 6, the annular member 50 presses the lower annular protrusion 34 of the load transfer structure 30 (i.e., the lower protrusion 42 of each load transfer piece 40A, 40B, 40C) against the inner peripheral surface of the rehabilitation lining material 12 to fix each load transfer piece 40 to the rehabilitation lining material 12, and is formed in a ring shape that follows the inner peripheral surface of the lower annular protrusion 34. The annular member 50 can be formed, for example, from a metal material, a resin material, etc.

The annular member 50 of this embodiment is formed so that the outer diameter gradually decreases from one end to the other end in the axial direction. Furthermore, in this embodiment, the inner diameter of the annular member 50 is formed constant in the axial direction, and as shown in FIG. 6, the annular member 50 has a wedge-shaped cross section in the axial direction (i.e., the vertical direction in the installed state). This annular member 50 is installed so that the side with the larger outer diameter is located at the top, and by pushing the annular member 50 into the load transfer structure 30 from above, it is fitted and fixed to the inner circumferential surface of the load transfer structure 30 by the wedge action. In addition, as a result, the lower annular protrusion 34 of the load transfer structure 30 is pressed against the inner circumferential surface of the rehabilitation lining material 12 over the entire circumferential area and fixed. The annular member 50 may be structured to be fixed to the load transfer structure 30 by applying an adhesive between the load transfer structure 30 and the annular member 50.

The annular member 50 is not limited to having a wedge-shaped cross section, and may be, for example, a member formed in an annular shape that can be expanded or contracted. FIG. 10 is a diagram showing another example of the annular member 50. As shown in FIG. 10(a), the annular member 50 has a band-shaped body 52 having a predetermined rigidity formed of a metal material or the like, and fixing members 53, 54 provided at both ends of the band-shaped body 52. The band-shaped body 52 is formed by bending a single plate material into an annular shape. The fixing members 53, 54 are substantially trapezoidal members, and as shown in FIG. 10(b), the respective inclined leg portions 53A, 54A are provided so as to contact and face each other when the annular member 50 is in an expanded state.

Next, the construction method of the manhole rehabilitation structure 10 of the second embodiment will be explained using Figures 11 to 14.

First, as shown in FIG. 11, a rehabilitation lining material 12 is installed inside the existing manhole 20 (rehabilitation manhole installation process).

The rehabilitation lining material 12 is installed in the following procedure. First, the cover 19 is removed from the existing manhole 20, and the invert portion 22 is removed. The receiving frame 18, adjustment mortar 17, and adjustment ring 14 can remain in place. After that, the unhardened cylindrical rehabilitation lining material 12 is introduced into the existing manhole 20. At this time, the upper and lower openings of the rehabilitation lining material 12 are blocked by upper and lower packers, and the rehabilitation lining material 12 is introduced into the existing manhole 20 using a crane while suspended by a wire rope attached to the upper packer.

Next, compressed air is supplied to the inside of the rehabilitation lining material 12 using a compressor. The compressed air is supplied to the inside of the rehabilitation lining material 12 through an air supply pipe that has one end connected to the compressor, passes through the upper packer, and has the other end extending into the rehabilitation lining material 12. After the rehabilitation lining material 12 expands and increases in diameter inside the existing manhole 20 due to the compressed air, a light irradiation device is introduced into the rehabilitation lining material 12 from the device introduction portion formed in the upper packer.

Then, compressed air is supplied into the lining material 12 by the compressor, and the outer peripheral surface of the lining material 12 is brought into close contact with the inner wall surface of the existing manhole 20. The light irradiation device is then removed, and the hardened lining material 12 is subjected to pipe opening treatment to form the sewer pipe mounting holes 28, 29, upper opening, and lower opening. In the hardened state of the lining material 12, the upper edge of the lining material 12 may extend to the height of the adjustment ring 14 or the adjustment mortar 17, and the height of the upper end surface 12a of the lining material 12 can be adjusted to fit the installation position of the load transfer structure 30 by pipe opening treatment of the upper opening. It is preferable to mark the location where the upper opening of the lining material 12 is to be pipe opening treatment in advance. After the rehabilitation lining material 12 is installed, a new invert section 22 is installed at the bottom of the rehabilitation lining material 12.

After the rehabilitation manhole installation process, as shown in FIG. 12, the inner surface 14a of the adjustment ring 14 is cut to form an annular notch 15 on the inner surface 14 (adjustment ring cutting process).

The adjustment ring 14 can be cut using a known cutting machine (not shown) equipped with a cutting blade. In this embodiment, when forming the annular cutout 15 in the cutting process, a part of the upper end surface 20a of the existing manhole 20 is exposed to form the annular recess 15A. This annular recess 15A is formed in an annular shape concentric with the upper opening of the rehabilitation lining material 12, and the outer diameter of the annular recess 15A is formed to be equal to the outer diameter of the structure body 32 of the load transfer structure 30. The annular cutout 15 is formed inside the multiple anchor bolts 11 that pass through the adjustment ring 14.

Next, the main body 42 of the multiple load transfer pieces 40A, 40B, and 40C is inserted into the annular cutout 15, and the annular load transfer structure 30 is fitted and installed into the annular cutout 15 (load transfer structure installation process).

Figure 13 is a cross-sectional view of the portion indicated by line B-B in Figure 12, and is a diagram illustrating the procedure for inserting multiple load transmission pieces 40A, 40B, and 40C into the annular cutout portion 15. In Figure 13, dots are added to the rehabilitation lining material 12 for easy understanding. As shown in the example, the multiple load transmission pieces 40A, 40B, and 40C are inserted into the annular cutout portion 15 sequentially from the inside of the adjustment ring 14 so that the main body portion 42 is placed overlapping both the upper end surface 20a of the existing manhole and the upper end surface 12a of the rehabilitation lining material 12. The load transmission piece 40C having parallel side edges 41a and 41b is inserted last. Also, as shown in Figure 14, the main body portion 42 of each of the load transmission pieces 40A, 40B, and 40C is fitted into the annular recess 15A so that the lower protruding piece 44 abuts against the inner peripheral surface of the rehabilitation lining material 12.

After the main body parts 42 of all the load transfer pieces 40A, 40B, 40C have been inserted into the annular cutouts 15, filler 48 is injected into the gaps formed between the main body parts 42 of adjacent load transfer structure pieces 40 as necessary (filler injection process). Then, an annular member 50 is installed inside the lower annular protrusion 34 of the load transfer structure 30, and the load transfer structure 30 is fixed to the rehabilitation lining material 12 (annular member installation process). This completes the manhole rehabilitation structure 10 shown in FIG. 5.

In the above-mentioned construction method, after the rehabilitation manhole installation process, the adjustment ring 14 is cut to form the annular cutout portion 15. Alternatively, the rehabilitation lining material 12 may be installed after the adjustment ring 14 is cut to form the annular cutout portion 15.

In the manhole rehabilitation structure 10 of this embodiment, when a load F is applied to the cover 19 by a person or vehicle passing over the cover 19, the load F is transmitted from the cover 19 to the load transmission structure 30 via the receiving frame 18, the adjustment mortar 17, and the adjustment ring 14, and is transmitted to the upper end surface 20a of the existing manhole 20 and the upper end surface 12a of the rehabilitation lining material 12 below the structure body 32 of the load transmission structure 30. As a result, even if the existing manhole 20 can no longer withstand the required vertical load F due to aging, the load received by the cover 19 can be transmitted to the new rehabilitation lining material 12, making full use of the load-bearing performance of the rehabilitation lining material 12 and maintaining the performance of the manhole.

The load transfer structure 30 is composed of multiple load transfer pieces 40A, 40B, and 40C that are divided in the circumferential direction, and the annular load transfer structure 30 can be installed by inserting each of the load transfer pieces 40A, 40B, and 40C into the annular cutout portion 15.

In addition, even if the existing manhole 20 collapses due to deterioration to the extent that it cannot withstand the vertical load F from above, the ring-shaped members 50 fix each load transmission piece 40 to the rehabilitation lining 12, so that the vertical load F can be appropriately transmitted to the new rehabilitation lining 12. Specifically, when the existing manhole 20 cannot withstand the vertical load F from above due to deterioration and the upper end surface 20a collapses, a force that bends the load transmission piece 40 toward the existing manhole 20 (i.e., a bending moment that moves the radially outer side of the body 42 of the load transmission piece 40 downward) acts on the load transmission piece 40 due to the vertical load F transmitted from the cover 19 to the existing manhole 20. In the manhole rehabilitation structure 10 of this embodiment, as shown in FIG. 6, the lower protruding piece 44 of the load transmission piece 40 is pressed against the inner peripheral surface of the rehabilitation lining material 12 by the annular member 50, and each load transmission piece 40 is fixed to the rehabilitation lining material 12. This stabilizes the installation state of each load transmission piece 40 and prevents the load transmission piece 40 from warping, thereby allowing the vertical load F to be properly transmitted to the upper end surface 12a of the rehabilitation lining material 12.

In the above-described embodiments, the rehabilitation lining material 12 containing a photocurable resin composition is used as a rehabilitation member (hereinafter also referred to as a "rehabilitation manhole") for rehabilitating the existing manhole 20. However, the rehabilitation manhole is not limited to this, and may be composed of, for example, a cylindrical repair material installed with a gap inside the existing manhole 20 and a backfill material filled in the gap between the repair material and the existing manhole 20. A rehabilitation manhole using a backfill material is generally not a freestanding structure that does not depend on the existing manhole 20, but has a composite structure that is integrated with the existing manhole 20 to stiffen the existing manhole 20. Even if the load transfer structure 30 is not arranged, it can indirectly support a vertical load through the existing manhole 20, but by interposing the load transfer structure 30, it becomes possible to apply a vertical load directly to the upper end surface of the rehabilitation manhole.

In this way, the manhole rehabilitation structure 10 of the present invention may use a backfill material as the manhole to be rehabilitated, but by using the rehabilitation lining material 12, it is possible to make the structure thinner than one that uses a backfill material, while still having high strength and able to withstand the required load. For example, if the thickness of the existing manhole 20 is 100 mm, the thickness of the rehabilitated manhole will be 70 to 80 mm if a backfill material is used, but if the rehabilitation lining material 12 is used, the thickness can be reduced to 10 to 17 mm, making it possible to make a self-supporting structure that can withstand the required load without relying on the existing manhole 20.

Third Embodiment
Next, a third embodiment of the manhole rehabilitation structure 10 will be described with reference to Figures 15 and 16. Figure 15 is an enlarged cross-sectional view similar to Figure 2, which shows a schematic diagram of the third embodiment of the manhole rehabilitation structure 10, and the same reference numerals are used to designate parts corresponding to those in the first embodiment. In the third embodiment described below, detailed description of the same configuration as in the first embodiment will be omitted.

As shown in FIG. 15, in this embodiment, the load transfer structure 30 has a structure body 32 formed in a circular plate shape, and an upper annular protrusion 38 protruding from the upper surface 32a of the structure body 32. As shown in FIG. 16, the load transfer structure 30 is composed of multiple load transfer pieces 40A, 40B, 40C. Each of the load transfer pieces 40A, 40B, 40C has a body portion 42 that forms the structure body 32, and an upper protrusion piece 47 that forms the upper annular protrusion 34.

In this embodiment, as shown in Figs. 15 and 16, an annular body 55 is interposed between each of the load transfer pieces 40A, 40B, and 40C and the inner peripheral surface 14a of the adjustment ring 14. The upper protruding pieces 47 of each of the load transfer pieces 40A, 40B, and 40C are indirectly in contact with the inner peripheral surface 14a of the adjustment ring 14 via the annular body 55. The annular body 55 may have a similar configuration to the annular member 50 shown in the second embodiment. The outer diameter and inner diameter of the annular body 55 are set so that the outer peripheral surface of the annular body 55 is in contact with the inner peripheral surface 14a of the adjustment ring 14 and the inner peripheral surface of the annular body 55 is in contact with the outer peripheral surface of the upper annular protruding portion 38 of the load transfer structure 30. An adhesive may be applied to the outer peripheral surface and/or inner peripheral surface of the annular body 55.

After the annular cutout 15 is formed in the adjustment ring 14, the annular body 50 is placed above the annular cutout 15 on the inner circumferential surface 14a of the adjustment ring 14 before inserting each load transmission piece 40A, 40B, 40C into the annular cutout 15.

In the manhole rehabilitation structure 10 of this embodiment, as shown in FIG. 15, the load transmission structure 30 allows the vertical load F acting on the cover 19 to act on the rehabilitation lining material 12. In addition, by providing the upper protruding piece 47 on each load transmission piece 40, even if the existing manhole 20 becomes unable to withstand the vertical load F from above due to aging and a part of the upper end surface 20a of the existing manhole 20 collapses, the upper protruding piece 47 abuts against the inner peripheral surface 14a of the adjustment ring 14, thereby preventing the load transmission piece 40 from warping toward the existing manhole 20. In addition, by providing the annular body 55, the force acting on the adjustment ring 14 from the upper protruding piece 47 of the load transmission piece 40 via the annular body 55 can be dispersed in the circumferential direction, improving the load transmission performance and improving the durability of the load transmission structure 30 against the vertical load F.

The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the invention.

For example, the load transfer structure 30 may have only the structure body 32 and may not have the upper annular protrusion 36 or the lower annular protrusion 38 (i.e., each load transfer piece 40 may consist only of the body portion 42). Even in such a case, it is possible to apply a vertical load from above to the rehabilitation lining material 12 via the load transfer structure 30.

In the above embodiment, the annular cutout 15 is formed at the lower end of the adjustment ring 14. Alternatively, the annular cutout 15 may be formed at the center or upper end of the adjustment ring 14 in the vertical direction. Alternatively, the inner circumferential surface of the upper end of the existing manhole 20 may be cut all around to form the annular cutout 15 on the inner circumferential surface of the upper end of the existing manhole 20. Alternatively, the inner circumferential surface of the adjustment ring 14 and the inner circumferential surface of the upper end of the existing manhole 20 may be cut all around to form one annular cutout 15. In either case, the load transfer structure 30 overlaps the upper end surface 12a of the rehabilitation lining material 12 and is fitted into the annular cutout 15 while abutting against the upper end surface 12a.

10 Manhole rehabilitation structure 11 Anchor bolt 12 Rehabilitation lining material (rehabilitation manhole)
12a Upper end surface of lining material for rehabilitation 14 Adjustment ring (existing adjustment ring)
Description of the Reference Numerals 14a Inner circumferential surface of adjustment ring 15 Annular cutout portion 15A Annular recess 17 Adjustment mortar 18 Receiving frame 19 Lid 20 Existing manhole 20a Upper end surface of existing manhole 30 Load transfer structure 32 Structure body 32a Upper surface of structure body 32b Lower surface of structure body 34 Upper annular protruding portion 38 Lower annular protruding portion 40A, 40B, 40C Load transfer piece 42 Main body portion 44 Lower protruding piece 47 Upper protruding piece 48 Filler material 50 Annular member 55 Annular body

Claims (6)

An existing adjustment ring for height adjustment placed on an existing manhole;
A manhole rehabilitation structure comprising: a rehabilitation manhole installed inside the existing manhole,
An annular cutout portion formed on the inner circumferential surface of the existing adjustment ring and/or the inner circumferential surface of the upper end portion of the existing manhole, the annular cutout portion extending around the entire circumference of the existing adjustment ring and/or the existing manhole;
and an annular load transfer structure that is fitted into the annular cutout and overlaps with an upper end surface of the rehabilitation manhole,
A manhole rehabilitation structure, characterized in that the load transfer structure is composed of a plurality of load transfer pieces divided in the circumferential direction. Each load transfer piece is
A plate-shaped main body portion overlapping the upper end surface of the rehabilitation manhole, and a lower protruding piece protruding from the lower surface of the main body portion and abutting against the inner circumferential surface of the rehabilitation manhole,
2. A manhole rehabilitation structure as described in claim 1, further comprising an annular member that presses the lower protruding pieces of each load transmission piece against the inner circumferential surface of the manhole from inside the manhole. Each load transfer piece is
A manhole rehabilitation structure as described in claim 1, characterized in that it has a plate-shaped main body portion overlapping the upper end surface of the rehabilitation manhole, and an upper protruding piece protruding from the upper surface of the main body portion and directly or indirectly abutting the inner surface of the existing adjustment ring stacked on the main body portion. A manhole rehabilitation structure as described in claim 3, characterized in that it is provided with an annular body interposed between the upper protruding piece of each load transmission piece and the inner surface of the existing adjustment ring. A manhole rehabilitation structure according to any one of claims 2 to 4, characterized in that a filler material is filled into the gap between the main body parts of adjacent load transmission pieces. A method for constructing a manhole rehabilitation structure according to any one of claims 1 to 5,
A process of cutting the inner circumferential surface of the existing adjustment ring and/or the inner circumferential surface of the upper end portion of the existing manhole around the entire circumference to form the annular notch portion;
and a step of inserting the plurality of load transfer pieces into the annular cutout portion to install the load transfer structure.

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