Rehabilitation method for existing sewer pipes

Abstract

The present invention provides a method for partially repairing and rehabilitating existing conduits consisting of manholes having a circular and / or irregular shape, and for providing an existing conduit rehabilitation method that is excellent in chemical resistance. [Solution] A method for repairing and rehabilitating a portion of an existing sewer pipe consisting of a manhole and a sewer pipe having a circular and / or irregular shape, wherein the method is: The process involves fixing a lattice-shaped reinforcing material made of inorganic fibers to the inner surface of the existing conduit, A step of fixing a sheet-like and / or panel-like structure made of synthetic resin to the back of the reinforcing material with fasteners, A step of allowing an injection material to flow into the space formed between the reinforcing material and the structure and curing and solidifying it, After the injection material has cured and solidified, the process involves welding the synthetic resin to the joints formed in the structure. This is a method for rehabilitating existing pipes, characterized by consisting of the following.

Description

[Technical Field]

[0001] The present invention relates to an existing pipeline rehabilitation method for repairing and rehabilitating a part of an existing pipeline formed of a manhole, and particularly relates to an existing pipeline rehabilitation method excellent in chemical resistance. [Background Art]

[0002] Manholes are provided at positions where the starting point, direction, gradient, pipe diameter and the like of a pipeline change, positions where steps occur, positions where pipelines meet, and positions required for maintenance and management. A manhole is a fundamental facility for maintaining and managing the entire pipeline facility including pipelines, rainwater discharge chambers, discharge outlets, catch basins, connecting pipes and the like, and performing inspection, diagnosis investigation, repair and reconstruction. Therefore, except for small manholes that cannot be accessed by people, it is important to keep manholes accessible to people at all times, and in particular, it is necessary to ensure safety for lifting and lowering.

[0003] Sewerage facilities including manholes need to maintain their service life as long as possible through proper maintenance. However, in recent years, deterioration and corrosion of sewer concrete structures caused by sulfuric acid resulting from the generation of hydrogen sulfide gas have attracted increasing attention. Similar to other civil engineering facilities, concrete structures of manholes may also deteriorate due to neutralization, alkali-aggregate reaction and the like. In particular, corrosion caused by sulfuric acid (hereinafter referred to as concrete corrosion), which is classified as biochemical erosion specific to sewerage structures, covers the widest range of objects and has a high deterioration rate, so urgent and appropriate countermeasures are required. In addition, corrosion of concrete by sulfuric acid is likely to occur in manholes at the discharge port of pressure feeding pipes, pipelines downstream thereof, and manhole parts with large steps or drops.

[0004] Various methods have been conventionally proposed as methods for repairing existing pipelines. Among these methods, the pipe-forming method is one of the representative methods. In this pipe-forming method, after a spacer is installed on the upper inner surface of an existing pipe, a long strip-shaped pipe component is spirally wound in the existing pipe, and adjacent winding side edges are joined to assemble a tubular body. It is known that performing this assembly process using pipe-making equipment can reduce the amount of manual labor required and increase the daily progress made in the process.

[0005] The above process involves passing a nozzle and hose for injecting backfill material between the existing pipe and a spacer installed on the upper inner surface of the pipe, and injecting backfill material through the nozzle to fill the space between the existing pipe and the tubular body. At this time, the spacer ensures space for inserting the nozzle and hose, space to facilitate the distribution of backfill material, and prevents the tubular body from floating up due to the buoyancy of the backfill material. Subsequently, as the backfill material hardens, the existing pipe and the tubular body become integrated, and the existing pipe is rehabilitated.

[0006] However, installing the above-mentioned spacers causes the internal cavity of the rehabilitated existing pipe to become significantly uneven, reducing the effective cross-section of the internal cavity. Therefore, in pipe rehabilitation methods, it is necessary to increase the effective cross-section of the rehabilitated existing pipe.

[0007] Furthermore, in manhole rehabilitation methods, it is sometimes necessary to increase the strength of the manhole after rehabilitation. Traditionally, this has been achieved by placing and reinforcing steel between the existing pipe and the pipe components. However, because reinforcing steel is prone to rusting, Patent Documents 1 and 2 disclose methods for reinforcing existing pipes and concrete structure walls using reinforced fiber lattice reinforcement, which is made by laminating carbon fibers or glass fibers in a lattice pattern, as an alternative to reinforcing steel.

[0008] Furthermore, Patent Document 3 discloses a corrosion-resistant sheet made of synthetic resin, a corrosion-resistant concrete structure, and a construction method applicable to corrosion protection of concrete structures such as manholes and pipelines in sewers. It discloses that the corrosion-resistant sheet is applied to the concrete surface by impregnating a fabric with a room-temperature curing adhesive and then adhering it to it.

[0009] However, each document highlighted various challenges, such as the increased number of work steps due to the large-scale installation of equipment into pipes and manholes, seismic resistance during natural disasters, and increased wear and tear due to aging, necessitating countermeasures.

[0010] Furthermore, manholes are constructed by embedding and connecting structural members such as vertical walls and sloping walls in the ground. Due to natural disasters as described above and deterioration over time, it may be necessary to repair or rehabilitate the entire manhole. On the other hand, depending on the installation location, a portion of the manhole may suffer significant damage. In this case as well, the entire manhole can be repaired or rehabilitated. However, depending on the cost of repair or rehabilitation and the extent of the damage, it may be desirable to repair only a portion of the manhole. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Patent No. 5774467 [Patent Document 2] Japanese Patent Publication No. 2010-189834 [Patent Document 3] Japanese Patent Publication No. 2001-32309 [Overview of the project] [Problems that the invention aims to solve]

[0012] This invention was made to solve the problems of the prior art described above, and provides a rehabilitation method for existing pipes consisting of manholes. [Means for solving the problem]

[0013] The invention according to claim 1 is, A method for repairing and rehabilitating a portion of an existing sewer pipe consisting of manholes and sewer pipes having a circular and / or irregular shape, wherein the method is: The process involves fixing a lattice-shaped reinforcing material made of inorganic fibers to the inner surface of the existing conduit, a step of fixing, with a fixture, a structure formed of a synthetic resin that has a sheet shape and / or a panel shape to a back surface of the reinforcing member; a step of causing a grouting material to flow into a space formed between the reinforcing member and the structure, and allowing the grouting material to cure and solidify; after the grouting material cures and solidifies, a step of welding the synthetic resin to joint portions formed in the structure; An existing pipe culvert rehabilitation method characterized by comprising the steps described above.

[0014] The invention according to claim 2 is the existing pipe culvert rehabilitation method according to claim 1, characterized in that the inorganic fibers are carbon fibers.

[0015] The invention according to claim 3 is the existing pipe culvert rehabilitation method according to claim 1 or 2, characterized in that the synthetic resin is a polyethylene-based resin.

[0016] The invention according to claim 4 is the existing pipe culvert rehabilitation method according to claim 3, characterized in that staggered protrusions are provided at regular intervals on a back surface of the structure.

[0017] The invention according to claim 5 is the existing pipe culvert rehabilitation method according to claim 3, characterized in that the synthetic resin is thermally fused to the joint portions.

[0018] The invention according to claim 6 is the existing pipe culvert rehabilitation method according to claim 1, characterized in that the grouting material is mortar that does not generate excess moisture after mixing. [Advantageous Effects of the Invention]

[0019] According to the existing pipe culvert rehabilitation method according to the invention of claim 1, which repairs and rehabilitates a part of an existing pipe culvert formed of a manhole and having a circular shape and / or an irregular shape, the method is excellent in chemical resistance and wear resistance even under a dangerous condition where sulfide gas is generated under sulfuric acid-based acidic drainage such as sewage, so that deterioration is small even after the rehabilitation work. Furthermore, since the number of work man-hours on site can be greatly reduced, the construction period can be shortened, and the effect of enabling rehabilitation construction to be performed easily and effectively is achieved. In particular, even when only a part of a manhole is repaired and rehabilitated, the above effect can be obtained.

[0020] In the invention according to claim 1, before the step of fixing the structure, a step of fixing a grid-like reinforcement made of inorganic fibers to the inner surface of the existing pipe culvert is performed. The manhole is provided in the vertical direction, the gravity applied in the vertical direction is small, and the cross-sectional area of the manhole is generally small. For this reason, reinforcement work is usually not required. However, manholes installed in large cities have a large cross-sectional area and may require reinforcement. In the present invention, prior to the above steps, a step of installing a reinforcement is provided in the manhole. This makes it possible to obtain a manhole with a reinforced wall surface.

[0021] According to the existing pipe culvert rehabilitation method according to claim 1, wherein the inorganic fiber of the invention according to claim 2 is made of carbon fiber, the method is not rusted like steel frames by acidic drainage such as sewage, has excellent chemical resistance, and also exhibits the effect of high mechanical strength such as tensile strength.

[0022] According to the existing pipe culvert rehabilitation method according to claim 1 or 2, wherein the synthetic resin of the invention according to claim 3 is made of polyethylene-based resin, the method has high airtightness and anticorrosion performance, is not easily broken, thus has excellent wear resistance, and further exhibits the effect of easy processability. Polyethylene-based resin has high extensibility, and even when a large force is applied to the existing pipe culvert such as during an earthquake, it has the effect of following the force and not breaking.

[0023] According to the existing pipe rehabilitation method described in claim 3, characterized in that staggered projections are provided at regular intervals on the back surface of the structure according to claim 4, after the injection material has cured and solidified, the staggered shape of the projections on the back surface of the structure provides excellent anchoring effect, preventing air from entering the space formed between the reinforcing material and the structure, and further preventing shifting or peeling after construction due to deterioration over time as the structure becomes heavier due to its own weight, thus providing the effect of stable maintenance.

[0024] The invention according to claim 5 is characterized by heat-sealing the joint portion with the synthetic resin. According to the existing pipe rehabilitation method described in claim 3, the joint portions, which are gaps, are firmly adhered to each other by the synthetic resin, so that the rehabilitation surface becomes seamless without gaps and can be formed into an integrated synthetic resin lining (tubular body).

[0025] The invention according to claim 6 is characterized in that the injection material is made of mortar that does not produce excess water after mixing. According to the existing pipe rehabilitation method described in claim 1, the water used when mixing the mortar can suppress the separation of sand, cement, aggregate, etc., after placement, thereby ensuring high strength and reducing the likelihood of cracking. [Brief explanation of the drawing]

[0026] [Figure 1A] This is a schematic diagram showing the first step of the existing pipe rehabilitation method according to the present invention. [Figure 1B] This is a schematic diagram showing the second step of the existing pipe rehabilitation method according to the present invention. [Figure 1C] This is a schematic diagram showing the third step of the existing pipe rehabilitation method according to the present invention. [Figure 1D] This is a schematic diagram showing the fourth step of the existing pipe rehabilitation method according to the present invention. [Figure 2A] This is a schematic diagram of the construction of the existing pipe rehabilitation method according to the present invention, and is a cross-sectional view of a circular pipe. [Figure 2B]This is a schematic diagram of the construction of the existing pipe rehabilitation method according to the present invention, and is a cross-sectional view of a rectangular pipe. [Figure 3] (a) A schematic diagram showing a reinforcing structure for the existing pipe rehabilitation method according to the present invention, a schematic diagram showing a front view. (b) A schematic diagram showing a reinforcing structure for the existing pipe rehabilitation method according to the present invention, a schematic diagram showing the intersection of the reinforcing bars of the reinforcing structure. [Figure 4] This is a schematic diagram showing the structure of the existing pipe rehabilitation method according to the present invention, where (1) is a front view and (2) is a cross-sectional view. [Figure 5] This is a schematic diagram showing the welding process to the joints of the existing pipe rehabilitation method according to the present invention. [Modes for carrying out the invention]

[0027] The following describes in detail, with reference to the drawings, a preferred embodiment of the existing pipe rehabilitation method according to the present invention.

[0028] As described above in the background art, the method for rehabilitating existing pipelines according to the present invention is suitably used, for example, in acidic corrosive environments such as sewers and drainage channels, when cracks such as damage or cracks occur in a part of the manhole wall. A manhole is a facility provided for inspection, cleaning, and ventilation of the inside of a pipeline. In sewer facilities, it serves both as a pipeline and as a facility for the maintenance and management of the pipeline. Manholes are generally small (inner diameter 220 mm) to large (inner diameter 600 mm). A manhole consists of a manhole frame, adjustment ring, slanted wall, straight wall, pipe mounting wall, and floor slab. It may also have a slanted wall with an internal slope. These components are constructed by assembling multiple components. The cross-sectional shape of the manhole may be circular and / or irregular. Irregular shapes include, for example, rectangles, horseshoes, and triangular portal shapes. These shapes may be combinations of multiple shapes. Furthermore, steps or landings for people to ascend and descend may be provided on the vertical walls inside the manhole.

[0029] As described above in the background art, the method for rehabilitating existing pipes according to the present invention is suitably used, for example, when damage occurs to the manhole itself or when cracks occur in a part of the wall surface, or in acidic corrosive environments such as sewers and drainage channels. Figure 1 shows an example in which a part of the straight wall 11 and the pipe attachment wall 12 have been rehabilitated.

[0030] In particular, the walls of manholes located above culverts such as sewers are exposed to a hydrogen sulfide atmosphere generated from sewage, and when hydrogen sulfide adheres to the walls of these existing culverts, it reacts with water to form sulfuric acid, which corrodes a portion of the manhole walls.

[0031] The rehabilitation method of the present invention is applied to manholes subjected to such acidic corrosive environments, particularly when corrosion, cracks, and damage to the manhole itself occur due to sulfuric acid or the like, making it difficult to maintain the structure and function. In this embodiment, the term "acidic corrosion environment" refers to an acidic atmosphere with a pH of 1 to 3.

[0032] The above rehabilitation method allows for the application of a primer or other coating with high adhesive properties to the wall surface as needed (see Figure 1A). This step is not always necessary. The application method involves evenly coating the wall surface using a brush or sprayer, but it is advisable to first ascertain the condition of the wall surface inside the pipe using a television camera or visual inspection before starting the application work.

[0033] In the circumstances described above, if any part of the wall surface to be repaired or rehabilitated is damaged or experiencing water infiltration, it is advisable to address these issues as appropriate. Furthermore, to enhance the adhesive effect after coating, it is preferable to perform surface preparation such as scraping or cleaning, or to perform high-pressure water washing on the wall surface.

[0034] Next, the reinforcing members 2 shown in Figures 3(a) and 3(b) may be fixed to the wall surface using fasteners after the coating process (not shown). This step is not mandatory. In the case of large manholes installed in large cities, etc., the strength of the manhole wall surface is required. In such cases, this step is performed to increase the strength of the manhole wall surface. Reinforcement 2 is composed of a grid of high-tensile carbon fibers integrally laminated together, as shown in Figures 3(a) and 3(b).

[0035] Reinforcement 2 has a very low specific gravity, and because the intersections of the grid are flush, it is thinner than reinforcing bars. Furthermore, because reinforcement 2 has high-strength and high-elasticity continuous reinforcing fibers arranged in both vertical and horizontal directions, it has the same reinforcing effect as reinforcing bars. Furthermore, since structure 2 does not rust and has excellent corrosion resistance, deterioration due to corrosion can be avoided.

[0036] Here, we will explain reinforcement 2 in detail with reference to Figure 3(b). The reinforcing element 2 typically comprises multiple reinforcing bars arranged in a grid pattern at right angles to each other, namely, longitudinal reinforcing bars 21 and transverse reinforcing bars 22. In this embodiment, each reinforcing bar 21, 22 is formed by laminating multiple carbon fiber layers 20a, in which carbon fibers are arranged in one direction, and then curing them.

[0037] Reinforcement 2 has a reinforcement width (w) of 1 to 50 mm, usually 2 to 20 mm, a thickness (t) of 1 to 100 mm, usually 2 to 20 mm, and a grid spacing (W) of 1 to 50 cm. Specifically, it is preferable that the reinforcement width (w) × thickness (t) is 6.6 square mm to 17.5 square mm, and the grid spacing (W) is 5 to 10 cm. Furthermore, although each reinforcing bar 21 and 22 is arranged perpendicular to each other, it is also possible to configure them to intersect at predetermined angles other than 90°, as desired, to form a grid.

[0038] Examples of reinforcing fibers used include inorganic fibers such as carbon fibers, glass fibers, and ceramic fibers; organic fibers such as fully aromatic polyamide fibers, fully aromatic polyester fibers, and aramid fibers; and metallic fibers such as titanium and steel. However, inorganic fibers are preferred due to their superior chemical resistance and mechanical strength, such as tensile strength, and carbon fibers are the most preferred.

[0039] Reinforcement 2 is fixed to the inner surface of the manhole using a physical fixing method. In particular, it is preferable to fix it using fasteners that are spaced a predetermined distance from the repaired or rehabilitated surface of the manhole. It is preferable that reinforcement 2 be embedded and fixed in the injection material, as this improves the reinforcement effect. Two or more reinforcement 2 may be fixed in layers. In particular, it is preferable to fix multiple layers in areas with severe damage. It is important that when installing reinforcement 2, there are no areas where reinforcement 2 is absent. It is important to avoid leaving any areas where reinforcement 2 is absent, for example, by installing and fixing two reinforcement 2 so that the lattice structure overlaps at the edges of reinforcement 2.

[0040] Thus, when carbon fiber is used as the reinforcing fiber, the reinforcing material 2 has a strength of 1400 N / mm². 2 The above tensile strength, and 100,000 N / mm² 2 It has the above tensile modulus of elasticity. For example, the reinforcing material 2 can be shrunk into a roll and easily transported into an existing pipe. Furthermore, it is preferable that the carbon fiber surface of reinforcing material 2 be surface-treated, as this can prevent scratches.

[0041] Furthermore, fasteners (concrete anchors) are used to secure the reinforcing material 2 (not shown). Plastic fasteners are preferred. Using plastic fasteners reduces the risk of corrosion due to acid.

[0042] Furthermore, the method of fixing the reinforcing bar 2 with the fasteners is not limited, but the fasteners are driven into the inner surface of the pipe at the corners of the grid of the reinforcing bar 2, that is, at the intersections of the grid bars 21 and 22 (see Figure 3(b)), and if necessary, a fastener retaining plate (not shown) or the like is used to press and fix the reinforcing bar 2 toward the inner surface of the pipe. The fasteners are driven into the ground every two or three squares of the reinforcing material 2, but the placement is not limited to this.

[0043] Next, a structure 3 (see Figure 4), which is a lining made of synthetic resin in the form of a sheet or panel, is inserted or placed on the upper surface of the fixed reinforcement 2, or on the surface of the manhole to be repaired, and then fixed using fasteners (see Figure 1B). On the back surface of the above-mentioned structure 3, protrusions are arranged at predetermined intervals to enhance integration with the solidified and cured injection material, which will be described later.

[0044] Structure 3 has a sheet-like and / or panel-like form. The sheet-like structure is effective when repairing and rehabilitating existing pipes that have curved surfaces because it conforms to the curved surface. The panel-like structure is effective when repairing and rehabilitating existing pipes that have flat surfaces, such as rectangular or triangular portal-type structures, because it can be assembled facing the flat surface. Structure 3 is fixed at a position where the desired thickness can be obtained, spaced apart from the repaired and rehabilitated surfaces of the existing pipe, as well as from the reinforcing material 2.

[0045] Structure 3 is provided with projections having a roughly V-shaped cross-section (see Figure 4(2)). As a result, these projections improve the entanglement with the grout material through an anchoring effect, allowing for greater integration between structure 3 and the grout material. Furthermore, the roughly V-shaped projections are arranged in a roughly staggered pattern on the sheet-like or panel-like structure (see Figure 4(1)). Therefore, when the grout material is injected, no air is trapped near structure 3, ensuring that the structure and the grout material are firmly fixed together, enabling robust pipe rehabilitation.

[0046] Furthermore, it is desirable to install the above-mentioned protrusions at intervals of 40 to 100 mm, and especially at 44 mm intervals.

[0047] Here, synthetic resins such as polyester, polyamide (nylon), polyethylene, and polypropylene can be used as the above-mentioned structure. From the viewpoint of chemical resistance and abrasion resistance, polyethylene resin is preferable. Polyethylene resin has approximately 30 times the abrasion resistance of polyvinyl chloride. In addition, polyethylene resin has excellent extensibility of approximately 600%. As a result, even if strain occurs in the existing conduit due to earthquakes or other events, it can expand and follow the bending displacement.

[0048] Furthermore, since the manhole becomes narrower, restricting the movement of people and materials, it is preferable to use a material that is strong even if it is thin for the structure. The thickness of this structure is preferably in the range of 2 to 10 mm, and especially 3 to 5 mm. If the thickness is less than 2 mm, the structure will be weak and will have difficulty standing on its own. Conversely, if the thickness exceeds 10 mm, the structure will be too strong, making construction difficult in areas with small diameters, and the structure will be heavy, which may cause displacement or spalling after construction.

[0049] Furthermore, when fixing the above-mentioned structure, the structure is first installed on the formwork and then secured with fasteners.

[0050] After fixing the structure 3 inside the reinforcement 2 within the manhole, the injection material is poured into the gap S between the reinforcement 2 and the structure 3 via the hose 8, filling the gap and allowing it to solidify (see Figure 1(C)). Mortar is preferred as the injection material, and inorganic cement mortar, polymer cement mortar, asphalt mortar, resin mortar, etc. can also be used, but it is particularly preferable to use one that does not shrink and does not have bleeding properties, meaning that no excess water is generated after mixing with the mortar.

[0051] Finally, the joints 10, which are gaps at the ends of the structure, are heat-sealed with a sealant made of the same material as the structure, such as a fast-curing polyethylene resin (see Figures 1D and 5). Additionally, scaffolding hardware and other necessary items will be restored inside the manhole as needed.

[0052] As explained above, according to the construction method of the present invention, rehabilitation work on concrete manholes in sewers can be completed in a short construction period. In particular, because it uses polyethylene structures with a thickness of 3-5 mm, it is self-supporting and allows for quick construction, even for repairs and rehabilitation of pipe walls. Furthermore, it enables appropriate rehabilitation and repair depending on the degree of deterioration of the concrete on the pipe wall. [Examples]

[0053] The effects of the present invention will be made clearer by showing the following examples of the existing pipe rehabilitation method according to the present invention. However, the present invention is not limited in any way to these examples.

[0054] The following describes one embodiment of the method for rehabilitating existing pipes according to the present invention. This embodiment involves the rehabilitation of a portion of the existing No. 1 manhole. This manhole has damage to its vertical wall section and part of its pipe connection section. Steps are provided in the vertical wall section to allow workers and materials to ascend and descend. In parts of the wall surface of the vertical wall 11 and the pipe attachment section 12, cracks had formed in the concrete of the vertical wall due to sulfuric acid, and water was seeping in through the cracks.

[0055] Herein, the reinforcing materials, structures, and injection materials used in this embodiment will be described below. Reinforcement 1 is a grid reinforcement made of carbon fiber. Considering the ease of construction during on-site work, reinforcement 1 was made with a reinforcement width (w) x thickness (t) of 6.6 square mm and a grid spacing (W) of 5 cm. Furthermore, regarding the carbon fibers used in the reinforcement according to the present invention, strength tests were conducted on their tensile strength and tensile modulus using a test method in accordance with the Japan Society of Civil Engineers standard JSCE-E531-1999 "Tensile Test Method for Continuous Fiber Reinforcements". The tensile strength was found to be 1400 (N / mm²). 2 ) or more, tensile modulus is 100,000 (N / mm²). 2 The above results were obtained for each case, confirming that they possess high strength.

[0056] Furthermore, the structure in this embodiment is made of polyethylene panels, and multiple panels were fixed to the wall surface according to the construction conditions to carry out the rehabilitation. Furthermore, the structure in this embodiment was tested using methods compliant with Japanese Industrial Standards JIS K6760 and 6301, respectively, to measure its strength (tensile strength, tear strength, elongation at fracture), specific gravity, and brittleness temperature, and it was confirmed that the measured values ​​converged within the range of the standards.

[0057] Furthermore, regarding the chemical resistance and abrasion resistance of this structure, tests were conducted using test methods compliant with the Japan Sewage Works Agency's "Guidelines and Manual for Corrosion Inhibition and Corrosion Prevention Technologies for Concrete Structures in Sewerage Systems" and Japanese Industrial Standard JIS K7204, respectively, and it was confirmed that the structure possesses the above-mentioned characteristics.

[0058] Furthermore, the injection material M used in this embodiment is a mortar having the aforementioned characteristics of being free from shrinkage and bleeding, and experiments were conducted on its compressive strength after curing for a predetermined number of days. The results are shown in Table 1.

[0059] [Table 1]

[0060] First, we examined the structure of the pipe wall to be rehabilitated and estimated its bending, shearing, and thrust-out shearing strength. While detailed calculations are omitted as the purpose was to determine the strength of the wall to be rehabilitated and confirm its strength in its existing state, the results showed that it possessed sufficient bending, shearing, and thrust-out shearing strength.

[0061] Next, we examined the current condition of the existing wall surface and considered its potential for rehabilitation. In this example, although the load-bearing capacity was confirmed to be sufficient in all cases during the load-bearing capacity check, the current condition of the wall surface shows cracks in the concrete and water seeping in through the cracks. Therefore, after examining the factors causing the discrepancy between the structural calculation results obtained above and the current condition, it was determined that the current wall surface deterioration is due to these factors, and a construction plan was created based on the calculation results and the condition of the wall surface.

[0062] Next, I will explain the construction process. First, as a preliminary step, wire protection and drainage treatment were carried out. Since the wall surface 4 to be reinforced has a power transmission line conduit opening and power transmission lines are drawn into it, it is necessary to protect the power transmission lines. In addition, water has seeped into wall surface 4 from cracks and is accumulating inside the box culvert, so the accumulated water was removed beforehand.

[0063] We performed water-stopping and water-diverting treatment on the leaking sections of the wall that needed repair. Since it was not possible to install reinforcements while the wall was flooded, we injected water-stopping materials such as urethane-based sealant into the leaking sections. In areas where the injection of this waterproofing material was insufficient to stop water leakage, measures such as installing water conduits were taken to stop leaks from the wall surface being constructed.

[0064] Furthermore, partial chipping and cross-sectional repair were carried out on a portion of the wall surface that needed rehabilitation. When the deterioration of the wall surface is severe, it may be difficult to integrate it with the reinforcement in its current state, making installation difficult. In such cases, chipping and cross-sectional repair of the wall surface is performed. In this example, due to the severe deterioration, the wall surface was chipped away to a depth of 5 cm, and polymer cement mortar was used to fill in cracks and areas with cross-sectional defects to repair it.

[0065] After repairing the aforementioned wall surface, the reinforcement 2 was set in the designated location according to the construction plan and secured using fasteners. In this process, it became necessary to connect and extend the reinforcing materials, and since the reinforcing materials were arranged in a grid pattern, they were installed and fixed in place, overlapping every two sections. In areas where the wall surface was severely deteriorated, two reinforcing materials were stacked and fixed, and one reinforcing material was fixed in the surrounding areas.

[0066] Furthermore, after setting and fixing the reinforcing members 2 in the designated locations, the formwork was installed in the direction of fluid flow in the conduit, and the panel-shaped structures 3 were attached to the dedicated formwork. Next, an injection material (PL mortar, manufactured by Chichibu Concrete Industry Co., Ltd.) was poured between the repaired and rehabilitated surfaces of the pipe and structure 3, and then cured and solidified. Reinforcement 2 was embedded in the mortar.

[0067] After the injected material had cured and solidified, the formwork attached to the structure was removed, and, if necessary, the joints of reinforcement 2 were sealed by heat fusion using polyethylene resin wire.

[0068] By implementing this construction method, the pipe wall P, the reinforcing material 2, and the structure 3 are integrated, allowing for reinforcement of cracks in the wall surface and suppression of wall displacement due to water pressure. Furthermore, compared to conventional rehabilitation methods, this method eliminates the need for rebar placement and concrete pouring, thus improving construction efficiency.

[0069] In this embodiment, the rehabilitation method was applied to rehabilitate a portion of a manhole. However, the rehabilitation method according to the present invention is applicable to various locations. Furthermore, when applying the reinforcing materials, structures, and injection materials used in the method according to the present invention, the shape of the wall surface to be rehabilitated is not limited to a flat surface; it can also be used for curved surfaces.

[0070] In addition to the embodiments described above, the present invention can be modified in various ways without altering the essence of the invention. In the above embodiment, a reinforcement made of carbon fiber was exemplified, but the present invention is not limited thereto, and a reinforcement made of reinforcing fibers mixed with fibers that have excellent chemical resistance and mechanical strength can also be applied.

[0071] Furthermore, although the above embodiment shows an example in which the reinforcing material 2 is fixed to the wall surface of the existing conduit P using a fastener 5, the present invention is not limited to this, and the reinforcing material 2 may also be fixed to the wall surface of the existing conduit P using simple fastening members such as small pegs or nails, and any method is applicable as long as it reduces the stress generated in the existing conduit P when attached to the wall surface of the existing conduit P.

[0072] Furthermore, while the above embodiment illustrates an example in which an injection material M is flowed and filled into the gap S between the pipe wall of the conduit and the structure 3, the present invention is not limited to this. For example, holes may be drilled from the inside of the tubular body formed by the structure using a drill or the like, and the injection material M may be filled through the holes using a nozzle or hose for injecting backfill material. The location and number of holes to be drilled can be appropriately set considering the size of the tubular body and the gap S.

[0073] Furthermore, in the supply of the injection material, a step of mixing short fibers into the injection material M may be incorporated. The short fibers mixed into the injection material M will entangle with the staggered protrusions of the structure, and after the injection material M has cured and solidified, the bonding force between the injection material M, the reinforcement 2, and the structure 3 will increase, making it possible to further increase the strength of the rehabilitated existing pipe P.

[0074] In the embodiments described above, examples were given of applying the method of the present invention to partially rehabilitate existing circular and rectangular conduits P. However, the method of the present invention can also be applied to rehabilitating existing conduits with irregular shapes, such as horseshoe-shaped or triangular conduits. [Industrial applicability]

[0075] The present invention is particularly suitable for use in narrow sections of manholes and waterways, as well as in environments where corrosive gases such as hydrogen sulfide are generated, in addition to conduits. This includes the rehabilitation method, reinforcing materials, structures, and injection materials used in the present invention. [Explanation of symbols]

[0076] 1: Rehabilitated pipes 2: Reinforcements 3: Structure 5: Fixtures 8: Hose 10: Joint area 11: Straight wall 12: Pipe mounting wall 20a: Carbon fiber layer 21, 22: Grid lines P: Existing conduit S: Gap M: Injection material

Claims

1. A method for repairing and rehabilitating a portion of an existing sewer pipe consisting of manholes and sewer pipes having a circular and / or irregular shape, wherein the method is: The process involves fixing a lattice-shaped reinforcing material made of inorganic fibers to the inner surface of the existing conduit, A step of fixing a sheet-like and / or panel-like structure made of synthetic resin to the back of the reinforcing material with fasteners, A step of allowing an injection material to flow into the space formed between the reinforcing material and the structure and curing and solidifying it, After the injection material has cured and solidified, the process involves welding the synthetic resin to the joints formed in the structure. A method for rehabilitating existing pipes, characterized by comprising the above.

2. The method for rehabilitating an existing pipe according to claim 1, characterized in that the inorganic fiber consists of carbon fiber.

3. The method for rehabilitating an existing pipe according to claim 1 or 2, characterized in that the synthetic resin is made of a polyethylene resin.

4. The method for rehabilitating an existing pipe according to claim 3, characterized in that staggered projections are provided at regular intervals on the back surface of the aforementioned structure.

5. The method for rehabilitating an existing pipe according to claim 3, characterized in that the synthetic resin is heat-fused to the joint portion.

6. The method for rehabilitating an existing pipe according to claim 1, characterized in that the injection material consists of mortar that does not generate excess water after mixing.

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