Underground pipe gallery deformation joint leakage repairing method

Abstract

The invention relates to the technical field of pipe gallery crack repairing, in particular to an underground pipe gallery deformation joint leakage repairing method. An underground pipe gallery deformation joint leakage repairing method comprises the following steps that original filler in a deformation joint is removed, and the deformation joint is filled with a backing slurry blocking material; mixing the high-ductility self-repairing waterproof mortar with water to prepare high-ductility self-repairing waterproof slurry, and filling the deformation joint with the high-ductility self-repairing waterproof slurry; the high-ductility polymer joint sealing mortar and water are mixed to prepare high-ductility polymer joint sealing slurry, the high-ductility polymer joint sealing slurry is smeared to the inner surface of the deformation joint, and a cavity is formed; a silane modified polyether material is poured into the cavity; and a W-shaped stainless steel plate is installed, polymer waterproof paint is brushed on the periphery of the deformation joint, and a waterproof sealing layer is formed. The three-in-one composite waterproof structure is adopted, the high-ductility self-repairing waterproof mortar, the W-shaped stainless steel plate and the silane modified polyether rubber are combined to construct an inner-blocking, middle-preventing and outer-sealing composite waterproof system, and the waterproof performance of the deformation joint in the dynamic deformation environment is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of pipe gallery crack repair technology, specifically to a method for repairing leakage in underground pipe gallery expansion joints. Background Technology

[0002] With the development of urban municipal pipeline networks, road excavation is frequently required due to pipeline upgrades, expansions, and maintenance. This not only affects residents' daily lives but also causes negative impacts such as environmental and noise pollution, hindering the development of urban infrastructure and the pace of environmental improvement. In recent years, urban integrated utility tunnels have gradually become a new model for resolving contradictions in urban infrastructure construction and are also known as "urban lifeline projects," serving as a crucial link in maintaining the normal operation of cities. Underground utility tunnels refer to public tunnels built underground for the centralized laying of power, communication, water supply, and drainage pipelines. Besides their widespread use in municipal engineering, they are also commonly used in industrial fields such as metallurgy and petrochemicals. However, in the use of utility tunnels, expansion joints are critical nodes designed to accommodate expansion and settlement, and are also high-risk areas for leakage. Current expansion joint leakage repair technologies have the following core defects: (1) Single waterproofing system: Traditional repairs often rely on a single material (such as ordinary waterproof mortar or rubber waterstop) or a single process, lacking multiple protective measures. Once a link fails, it will cause overall leakage. For example, ordinary waterproof mortar is rigid and has poor ductility, making it difficult to adapt to the dynamic deformation of the pipe gallery and easy to crack and form leakage channels; rubber waterstop is prone to aging due to long-term erosion by groundwater and does not bond firmly to the concrete base, making it easy to peel off at the interface.

[0003] (2) Lack of self-repair and dynamic adaptation capabilities: Existing materials have no self-repair function. When new cracks are generated in the pipe gallery due to soil settlement, they cannot be sealed in time, resulting in repeated leakage. At the same time, most repair materials have poor deformation adaptability and the elongation at break is generally less than 300%, making it difficult to cope with displacement deformation of the pipe gallery of ±5mm or more.

[0004] (3) Poor controllability of construction quality: There are no clear standards for the roughening depth and cleanliness of the base surface during the pretreatment stage, no requirements for layered compaction of materials, and no standardization of grouting pressure and number of times. As a result, the repair effect is greatly affected by human operation, and the secondary leakage rate is as high as 40% or more.

[0005] (4) Insufficient resistance to erosion and protection: The corrosiveness of groundwater and the long-term effects of soil pressure in the underground environment will accelerate the aging and damage of repair materials. Existing technologies lack protective structures against external mechanical impact and chemical erosion, thus shortening the repair life.

[0006] Therefore, there is an urgent need for a method to repair leakage in the expansion joints of underground utility tunnels that combines "multiple protection, self-repair, dynamic adaptation, and erosion resistance" to solve the bottleneck problems of traditional technologies. Summary of the Invention

[0007] The purpose of this application is to provide a method for repairing leakage in expansion joints of underground utility tunnels. This application adopts a "three-in-one" composite waterproof structure, which combines high-ductility self-healing waterproof mortar, W-shaped stainless steel plate, and silane-modified polyether rubber to construct a composite waterproof system of "internal plugging, middle protection and external sealing", which significantly improves the waterproof performance of expansion joints in dynamic deformation environments.

[0008] To achieve the above objectives, this application provides the following technical solution: A method for repairing leakage at expansion joints in underground utility tunnels includes the following steps: (1) Remove the original filler in the expansion joint, clean the expansion joint, and then fill it with backing grouting material; (2) Mix high-ductility self-healing waterproof mortar with water to make high-ductility self-healing waterproof slurry, and then fill it into the expansion joint; use the self-healing properties of high-ductility self-healing waterproof mortar to seal the leakage channels inside the expansion joint. (3) Mix the high-ductility polymer sealing mortar with water to make a high-ductility polymer sealing slurry, and then apply it to the inner surface of the expansion joint to seal the expansion joint, and form a cavity between the high-ductility polymer sealing slurry and the high-ductility self-healing waterproof slurry; the high-ductility polymer sealing mortar (slurry) is used to seal the outer side of the expansion joint. (4) After the high-ductility self-healing waterproof slurry and the high-ductility polymer sealing slurry have cured, grouting holes are opened on the side of the expansion joint. Silane-modified polyether material is injected into the cavity through the grouting holes and cured after filling. Silane-modified polyether material (i.e., silane-modified polyether rubber) is used to form a reconstituted rubber waterstop with excellent resistance to disturbance and deformation in the expansion joint. (5) Install a W-shaped stainless steel plate on the outside of the high-ductility polymer sealing slurry, and apply polymer waterproof coating around the expansion joint to form a waterproof sealing layer. Fix the W-shaped stainless steel plate to both sides of the expansion joint to form a mechanical waterproof barrier; the polymer waterproof coating forms a highly elastic, weather-resistant waterproof sealing layer.

[0009] Preferably, in step (1), the concrete base surface on both sides of the expansion joint is cleaned until there are no debris or loose concrete. Then, a backing grouting material with a thickness of 1-50 mm is filled into the bottom of the expansion joint and compacted until the backing grouting material is in close contact with the side wall of the expansion joint. The thickness of the backing grouting material is adapted to the thickness of the expansion joint, and the distance L between the backing grouting material and the inner wall of the pipe gallery is 160-200 mm. The backing grouting material is polystyrene foam board. The concrete base surface on both sides of the expansion joint is treated to be free of debris and loose concrete, so that the high-ductility self-healing waterproof mortar, high-ductility polymer sealing mortar, and silane-modified polyether material are tightly bonded to the concrete on both sides of the expansion joint.

[0010] Preferably, in step (2), the ratio of the high-ductility self-healing waterproof mortar to water is 0.13 to 0.18:1. The high-ductility self-healing waterproof slurry is filled into the outer side of the backing slurry material inside the deformation joint and compacted until it is in close contact with the side wall of the deformation joint. The above operation is repeated. The thickness of the high-ductility self-healing waterproof slurry filled each time does not exceed 25mm, and the total thickness of the high-ductility self-healing waterproof slurry is 50mm ± 10mm.

[0011] Preferably, the high-ductility self-healing waterproof mortar is formulated from P·O 42.5R silicate cement, R·SAC42.5 sulfoaluminate cement, quartz sand, penetrating crystallizing waterproofing agent, polypropylene fiber, redispersible latex powder and polycarboxylate superplasticizer in a mass ratio of 1:2~4:4~6:0.1~0.3:0.01~0.03:0.1~0.3:0.001~0.005. The quartz sand has a particle size of 0.15~0.6mm and the polypropylene fiber has a length of 6~12mm.

[0012] Preferably, in step (3), the ratio of the high-ductility self-healing waterproof mortar to water is 1:0.13 to 0.2, the thickness of the high-ductility polymer sealing slurry embedded in the deformation joint is 10 to 20 mm, and the high-ductility polymer sealing slurry is in close contact with the sidewall of the deformation joint; the height of the cavity is 100 mm ± 10 mm.

[0013] Preferably, the high-ductility polymer sealing mortar is prepared from P·O 42.5R silicate cement, R·SAC42.5 sulfoaluminate cement, quartz sand, polypropylene fiber, redispersible latex powder, and polycarboxylate superplasticizer in a mass ratio of 1:2-4:4-6:0.01-0.03:0.1-0.3:0.002-0.01. The quartz sand has a particle size of 0.15-0.6 mm, and the polypropylene fiber has a length of 6-12 mm.

[0014] Preferably, in step (4), grouting holes are drilled obliquely at a distance d of 200mm ± 10mm between the inner concrete wall surface on both sides of the expansion joint and the expansion joint to form grouting holes that communicate with the cavity. The angle α between the grouting hole and the inner wall surface of the pipe gallery on both sides of the expansion joint on the horizontal plane is 30 to 45°, and the diameter of the grouting hole is 10 to 30mm. When drilling obliquely multiple times, the distance between any two grouting holes on the inner wall surface of the pipe gallery is 500 to 1000mm.

[0015] More preferably, a stainless steel grouting nozzle with a check valve (gate valve) is installed in each grouting hole. The grouting nozzle is a Wenmo brand B8 water-stop needle, and the grouting nozzle is sealed and fixed to the grouting hole with epoxy resin. Silane-modified polyether material is injected into the cavity multiple times from bottom to top through the grouting nozzle, with each injection interval being 10-15 minutes. The grouting nozzle and gate valve are used to assist in the grouting construction.

[0016] Preferably, in step (5), the W-shaped stainless steel plate has a thickness of 2mm, a width of 30-50mm, and a yield strength of not less than 300MPa. The W-shaped stainless steel plate is symmetrically fixed to both sides of the deformation joint by anchors (expansion bolts) or adhesive to form a mechanical waterproof barrier.

[0017] More preferably, the polymer waterproof coating is prepared from P·O 42.5R silicate cement, quartz sand, styrene-acrylic emulsion, polypropylene fiber, polyether defoamer, and water in a mass ratio of 42.5:15-25:25-40:0.1-0.5:3-6. The quartz sand has a particle size of 0.15-0.6 mm, the polypropylene fiber has a length of 6-12 mm, and the polymer waterproof coating has a thickness of 2-3 mm, applied in two coats.

[0018] Beneficial effects: 1. This invention employs a "three-in-one" composite waterproof structure, combining high-ductility self-healing waterproof mortar / grout, W-shaped stainless steel plate, and silane-modified polyether material (silane-modified polyether rubber) to construct a composite waterproof system of "internal sealing, intermediate protection, and external sealing." Specifically, the high-ductility self-healing waterproof mortar penetrates deep into the expansion joint, filling and sealing it while achieving self-repair; the W-shaped stainless steel plate provides a stable mechanical waterproof barrier; and the silane-modified polyether rubber forms an intermediate elastic sealing layer, recreating a waterstop. The synergistic effect of these materials significantly improves the waterproof performance of the expansion joint under dynamic deformation environments.

[0019] 2. The high-ductility self-healing waterproof mortar of the present invention can penetrate into the fine cracks when filling deformation joints. After encountering water, it expands and crystallizes, automatically repairing new cracks caused by deformation, breaking through the limitation of traditional rigid sealing materials that are prone to cracking and failure. At the same time, its high ductility allows it to adapt to the deformation of the pipe gallery, avoiding leakage caused by brittle fracture of the material.

[0020] 3. This invention introduces a W-shaped stainless steel plate as the outer waterproof component. Its unique wave-shaped structure gives it good deformation adaptability and can effectively disperse the stress generated by the deformation of the pipe gallery. It is fixed by anchors and forms a stable connection with the concrete on both sides. Compared with traditional waterstops, it has higher waterproof reliability in complex stress environments and is not easy to shift or fall off.

[0021] 4. This invention selects high-performance elastic sealing material—silane-modified polyether rubber—as intermediate sealing material. It combines the weather resistance of silicone sealant and the high elasticity of polyurethane sealant, has strong adhesion to concrete substrate, maintains good elasticity in the range of -50℃ to 150℃, and can extend with the expansion and contraction of deformation joints, effectively resisting groundwater erosion and significantly extending the service life of waterproofing system. Attached Figure Description

[0022] Figure 1This is a cross-sectional view of an embodiment of the present invention.

[0023] In the diagram: 1. Backing grout-blocking material; 2. High-ductility self-healing waterproof grout; 3. Silane-modified polyether material; 4. High-ductility polymer sealing grout; 5. W-shaped stainless steel plate; 6. Polymer waterproof coating; 7. Grouting hole; 8. Grouting nozzle. Detailed Implementation

[0024] The present application will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of explanation and not by way of limitation. In fact, those skilled in the art will understand that modifications and variations can be made to the present application without departing from the scope or spirit of the present application. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention should fall within the scope of protection of the embodiments of the present invention.

[0025] A method for repairing leakage at expansion joints in underground utility tunnels includes the following steps: (1) Remove the original filling material in the expansion joint, clean the concrete base surface on both sides of the expansion joint until there are no debris and loose concrete, and then fill the bottom of the expansion joint with a backing grouting material with a thickness of 1 to 50 mm and compact it until the backing grouting material is in close contact with the side wall of the expansion joint. The distance L between the backing grouting material and the inner wall of the pipe gallery is 160 to 200 mm. The backing grouting material is polystyrene foam board, and the thickness of the backing grouting material is adapted to the thickness of the expansion joint.

[0026] (2) Mix high-ductility self-healing waterproof mortar with water at a mass ratio of 0.13 to 0.18:1 to prepare high-ductility self-healing waterproof slurry. Then fill the slurry into the expansion joint and press it to make it densely contact the sidewall of the expansion joint. Repeat the above operation and fill again. The thickness of the high-ductility self-healing waterproof slurry filled each time should not exceed 25 mm, and the total thickness of the high-ductility self-healing waterproof slurry should be 50 mm ± 10 mm. The high-ductility self-healing waterproof mortar is made of P·O in a mass ratio of 1:2 to 4:4 to 6:0.1 to 0.3:0.01 to 0.03:0.1 to 0.3:0.001 to 0.005. It is formulated with 42.5R silicate cement, R·SAC42.5 sulfoaluminate cement, quartz sand, penetrating crystallizing waterproofing agent, polypropylene fiber, redispersible latex powder and polycarboxylate superplasticizer. The particle size of the quartz sand is 0.15-0.6mm and the length of the polypropylene fiber is 6-12mm.

[0027] (3) Mix high-ductility polymer sealing mortar with water at a mass ratio of 0.13 to 0.2:1 to prepare high-ductility polymer sealing slurry, and then apply it to the inner surface of the expansion joint to seal the expansion joint, so that a cavity is formed between the high-ductility polymer sealing slurry and the high-ductility self-healing waterproof slurry; the thickness of the high-ductility polymer sealing slurry embedded in the expansion joint is 10 to 20 mm, and the high-ductility polymer sealing slurry is in close contact with the side wall of the expansion joint; the height of the cavity is 100 mm ± 10 mm; the high-ductility polymer sealing mortar is composed of P·O in a mass ratio of 1:2 to 4:4 to 6:0.01 to 0.03:0.1 to 0.3:0.002 to 0.01. It is formulated with 42.5R silicate cement, R·SAC42.5 sulfoaluminate cement, quartz sand, polypropylene fiber, redispersible latex powder, and polycarboxylate superplasticizer. The particle size of the quartz sand is 0.15-0.6 mm, and the length of the polypropylene fiber is 6-12 mm.

[0028] Among them, P·O 42.5R silicate cement is P·O 42.5R cement from Hubei Daye Jianfeng Cement Co., Ltd., R·SAC42.5 sulfoaluminate cement is R·SAC42.5 cement from Yicheng Anda Special Cement Co., Ltd., penetrating crystallizing waterproofing agent is TU-TJN type from Wuhan Sanyuan Special Building Materials Co., Ltd., and redispersible latex powder is Wanwei 8020 adhesive powder. (4) After the high-ductility self-healing waterproof slurry and the high-ductility polymer sealing slurry have cured, diagonally drill holes at a distance d of 200mm ± 10mm between the concrete inner wall surface on both sides of the expansion joint and the expansion joint to form grouting holes that communicate with the cavity. The angle α between the grouting hole and the inner wall surface of the pipe gallery on the horizontal plane is 30-45°, and the diameter of the grouting hole is 10-30mm. When drilling diagonally multiple times, the distance between any two grouting holes on the inner wall surface of the pipe gallery is 500-1000mm. The concrete inner wall surface on both sides of the expansion joint is the two sides inside the expansion joint, and the inner wall surface of the pipe gallery is the wall surface perpendicular to the two sides, that is, the surface on which the W-shaped stainless steel plate is installed. The hole spacing is vertical, arranged from bottom to top, or only one hole can be set.

[0029] Each grouting hole is fitted with a stainless steel grouting nozzle with a check valve (gate valve). The grouting nozzle is a Wenmo brand B8 water-stop needle. The gap between the grouting nozzle and the hole wall is sealed and fixed with epoxy resin. Silane-modified polyether material is injected into the cavity multiple times from bottom to top through the grouting nozzle, with an interval of 10 to 15 minutes between each injection. After filling, it is cured.

[0030] (5) Install a W-shaped stainless steel plate with a thickness of 2 mm, a width of 30-50 mm, and a yield strength of not less than 300 MPa on the outside of the high-ductility polymer sealing slurry. The W-shaped stainless steel plate is symmetrically fixed to both sides of the expansion joint using anchors (expansion bolts) or adhesive to form a mechanical waterproof barrier. Apply polymer waterproof coating around the expansion joint to form a waterproof sealing layer. The polymer waterproof coating is prepared from P·O 42.5R silicate cement, quartz sand, styrene-acrylic emulsion, polypropylene fiber, polyether defoamer, and water in a mass ratio of 42.5:15-25:25-40:0.1-0.5:3-6. The quartz sand has a particle size of 0.15-0.6 mm, the polypropylene fiber has a length of 6-12 mm, and the polymer waterproof coating is applied in two coats with a thickness of 2-3 mm. The polymer waterproof coating is TU-JS waterproof coating produced by Wuhan Sanyuan Special Building Materials Co., Ltd., with a liquid-to-powder ratio of 0.6:1, used to form a waterproof sealing and protective layer.

[0031] Example 1 Leakage occurred at the expansion joints of an underground utility tunnel in a certain city. The method of this invention was used for repair, and the specific implementation method is as follows: (1) Use a pneumatic / electric pick to remove the original filling material in the expansion joint, and use a high-pressure water gun to clean the loose concrete, dust and other debris from the side wall of the expansion joint. Fill the expansion joint with a 30mm thick polystyrene foam board 1 and compact it until the polystyrene foam board 1 is in close contact with the side wall of the expansion joint, keeping the distance L between the polystyrene foam board 1 and the inner wall of the pipe gallery 170mm.

[0032] (2) A high-ductility self-healing waterproof mortar is prepared by mixing P·O 42.5R silicate cement, R·SAC42.5 sulfoaluminate cement, quartz sand (particle size 0.15-0.6mm), penetrating crystallizing waterproofing agent, polypropylene fiber (length 6-12mm), redispersible latex powder and polycarboxylate superplasticizer in a mass ratio of 1:3:5.5:0.2:0.02:0.2:0.003. The high-ductility self-healing waterproof mortar is mixed with water in a mass ratio of 0.15:1 to obtain a high-ductility self-healing waterproof slurry. The slurry is injected into the outer side of the polystyrene foam board in the expansion joint using an SG-5 screw grouting machine. The slurry is injected in two stages, with each injection thickness not exceeding 25mm. After each injection, the slurry is compacted until it is in close contact with the structure on both sides of the expansion joint. The total thickness of the high-ductility self-healing waterproof slurry 2 is 50mm.

[0033] (3) The high-ductility polymer sealing mortar is prepared by mixing P·O 42.5R silicate cement, R·SAC42.5 sulfoaluminate cement, quartz sand (particle size of 0.15-0.6mm), polypropylene fiber (length of 6-12mm), redispersible latex powder and polycarboxylate high-efficiency water-reducing agent in a mass ratio of 1:3:5.5:0.02:0.2:0.006. The high-ductility polymer sealing mortar and water are mixed evenly in a mass ratio of 0.15:1 to obtain the high-ductility polymer sealing slurry. The high-ductility polymer sealing slurry 4 is applied to the inner surface of the deformation joint to seal the deformation joint, so that the high-ductility polymer sealing slurry 4 is embedded in the deformation joint with a thickness of 15mm and is in close contact with the structures on both sides of the deformation joint. A cavity with a thickness of 105mm is formed between the high-ductility polymer sealing slurry 4 and the high-ductility self-healing waterproof slurry 2.

[0034] (4) After the high-ductility polymer sealing slurry 4 and the high-ductility self-healing waterproof slurry 2 have cured (generally 2-3 hours), use an electric drill to drill at an angle at a distance d of about 200 mm from the concrete inner wall surface on the side of the expansion joint to form a grouting hole 7 that communicates with the cavity. The angle α between the grouting hole 7 and the two walls on both sides of the expansion joint on the horizontal plane is 30°. The diameter of the grouting hole 7 is 10 mm, and the depth should be such that it communicates with the cavity. When drilling at an angle multiple times, the distance between any two grouting holes 7 on the inner wall surface of the pipe gallery is 800 mm. A grouting nozzle 8 with a check valve structure (gate valve) is installed in each grouting hole 7. The grouting nozzle 8 is selected from the Wenmo brand B8 water-stop needle. The gap between the grouting nozzle 8 and the hole wall is sealed and fixed with epoxy resin glue. Inject silane-modified polyether material 3 into the cavity from bottom to top through the grouting nozzle 8. The time interval between each injection is 10 to 15 minutes until the cavity of the expansion joint is filled with silane-modified polyether material 3. The filling height of silane-modified polyether material 3 is 105 mm. The silane-modified polyether material used (KT-CSS-9019 silane-modified polyether water-curing grout, commonly known as liquid rubber) meets the requirements of the T / CECS10301-2023 standard "Silane-modified polyether grouting material". After filling, it is cured.

[0035] (5) Install a corrugated W-shaped stainless steel plate 5 on the outside of the high-ductility polymer sealing slurry 4. Fix the W-shaped stainless steel plate 5 symmetrically on both sides of the expansion joint with steel adhesive to form a mechanical waterproof barrier. The W-shaped stainless steel plate 5 is made of stainless steel plate with a thickness of 2mm and a yield strength of not less than 300MPa. The bending thickness and wave height are 5-8mm, the wave pitch is 15mm, and the width after bending is 50mm. Apply polymer waterproof coating 6 to the outside of the W-shaped stainless steel plate 5 to form a waterproof sealing layer. The polymer waterproof coating is TU-JS two-component polymer waterproof coating produced by Wuhan Sanyuan Special Building Materials Co., Ltd. Before application, mix the liquid and powder at a ratio of 0.6:1. Apply a thickness of about 3mm in two coats.

[0036] refer to Figure 1 In the treatment of leakage in expansion joints, the following materials are installed sequentially from the water-facing side to the backwater side: 1. Backing grouting material; 2. High-ductility self-healing waterproof slurry; 3. Silane-modified polyether material; 4. High-ductility polymer sealing slurry; 5. W-shaped stainless steel plate; and 6. Polymer waterproof coating.

[0037] Comparative Example 1 This comparative example relates to the field of waterproofing engineering technology for underground infrastructure, specifically addressing the leakage problem of expansion joints in underground utility tunnels. It employs the traditional process of "ordinary epoxy resin grouting + external rubber waterstop reinforcement" for treatment, applicable to leakage repair scenarios of expansion joints in underground concrete structures such as integrated utility tunnels and municipal drainage utility tunnels. As a performance comparison reference for subsequent invention patent solutions, it clarifies the technical limitations of traditional processes in the special environment of underground utility tunnels.

[0038] (1) First, use a wire brush to clean the moss, laitance, and debris in the joint and within 80mm on both sides. Then, use a high-pressure water gun to rinse the joint and remove any remaining debris. For the loose concrete part of the joint wall, use an electric drill and a chisel to remove it until a solid concrete base surface is exposed. Use sandpaper to polish the base surface within 50mm on both sides of the expansion joint to make its roughness reach Ra 12.5-25μm. Finally, wipe the base surface with anhydrous ethanol to remove oil and dust. After the base surface is dry (moisture content ≤6%), drill grouting holes every 300mm on both sides of the expansion joint (hole diameter 8mm, hole depth 40mm, intersecting the expansion joint at a 45° angle) and install grouting nozzles.

[0039] (2) Mix ordinary epoxy resin grout according to the ratio, and the mixing time is ≥5min to ensure uniform mixing and no sedimentation; pour the grout into the grout pump bucket, start the grout pump, and start low-pressure grouting from the grouting nozzle at one end of the expansion joint (initial pressure 0.2MPa). After the adjacent grouting nozzle overflows with uniform grout, close the current grouting nozzle and push it to the subsequent grouting nozzles in sequence; after all grouting nozzles have completed grouting, maintain the pressure at 0.5MPa for 30min to ensure that the grout fully fills the gap; then remove the grouting nozzles, seal the grouting holes with polyurethane sealant, and let stand for 7 days to allow the grout to fully cure.

[0040] (3) After the epoxy resin grout has cured, clean and dry the surface of the expansion joint and the base surface within 80mm on both sides again; apply epoxy resin adhesive evenly to the base surface and the bonding surface of the rubber waterstop (width 40mm / side), with a coating thickness of 1.0-1.2mm, and let it stand for 2 hours after application (until the adhesive is surface dry and not sticky to the touch); cover the expansion joint with the rubber waterstop in the center, and tap it evenly along the length of the waterstop with a rubber hammer to ensure that the adhesive is fully bonded to the base surface without air bubbles or hollow areas; apply polyurethane sealant (width 10mm, thickness 5mm) at the junction of the waterstop edge and the concrete base surface for sealing and reinforcement, and let it stand for 5 days until the adhesive and sealant are completely cured.

[0041] The traditional process of "ordinary epoxy resin grouting + external rubber waterstop reinforcement" in this comparative example has significant technical limitations in the treatment of leakage at expansion joints in underground utility tunnels: First, ordinary epoxy resin grouting material is brittle and has poor resistance to deformation, making it unable to adapt to long-term dynamic deformation of the utility tunnel and prone to cracking and loss of waterproofing function; second, the external rubber waterstop relies on adhesive to bond with the concrete substrate, and in the environment of high underground humidity and groundwater erosion, the bonding reliability is easily reduced, leading to the peeling of the waterstop; third, the overall waterproofing system has a low seepage pressure resistance level (can only withstand water pressure below 0.3MPa), which cannot meet the waterproofing requirements of utility tunnels with deep groundwater levels (burial depth > 3m), and has poor durability, with a short service life after treatment (usually ≤ 2 years), requiring frequent repairs, increasing the operation and maintenance costs and safety risks of the utility tunnel. The aforementioned defects indicate that the traditional process is no longer suitable for the complex and harsh operating environment of underground utility tunnels, providing a clear basis for comparison regarding the innovation and practicality of improved technical solutions in subsequent invention patents (such as using a combination of elastic epoxy grouting material and expansion waterstop, optimizing the interface bonding process, and adding a backing waterstop structure).

[0042] This invention combines three materials—high-ductility self-healing waterproof mortar, silane-modified polyether material, and W-shaped stainless steel plate—to form a composite waterproof system of "internal blocking, intermediate protection, and external sealing." The high-ductility self-healing waterproof mortar penetrates deep into the deformation joint to fill and seal it, achieving self-repair. The silane-modified polyether rubber forms an intermediate elastic sealing layer, and the W-shaped stainless steel plate provides a stable mechanical waterproof barrier, recreating a waterstop. The synergistic effect of these materials significantly improves the waterproof performance of the deformation joint under dynamic deformation conditions.

[0043] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0044] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for repairing leakage at expansion joints in underground utility tunnels, characterized in that, Includes the following steps: (1) Remove the original filler in the expansion joint, clean the expansion joint, and then fill it with backing grouting material; (2) Mix the high-ductility self-healing waterproof mortar with water to make a high-ductility self-healing waterproof slurry, and then fill it into the expansion joint; (3) Mix the high-ductility polymer sealing mortar with water to make a high-ductility polymer sealing slurry, then apply it to the inner surface of the expansion joint for sealing treatment, and form a cavity between the high-ductility polymer sealing slurry and the high-ductility self-healing waterproof slurry. (4) After the high-ductility self-healing waterproof slurry and the high-ductility polymer sealing slurry have cured, grouting holes are opened on the side of the expansion joint. Silane-modified polyether material is injected into the cavity through the grouting holes and cured after filling. (5) Install a W-shaped stainless steel plate on the outside of the high-ductility polymer sealing slurry, and apply polymer waterproof coating around the expansion joint to form a waterproof sealing layer.

2. The method for repairing leakage at expansion joints in underground utility tunnels according to claim 1, characterized in that, In step (1), the concrete base surface on both sides of the expansion joint is cleaned until there are no debris and loose concrete. Then, a backing grouting material with a thickness of 1 to 50 mm is filled into the bottom of the expansion joint and compacted. The distance L between the backing grouting material and the inner wall of the pipe gallery is 160 to 200 mm. The backing grouting material is polystyrene foam board.

3. The method for repairing leakage at expansion joints in underground utility tunnels according to claim 1 or 2, characterized in that, In step (2), the ratio of the high-ductility self-healing waterproof mortar to water is 0.13 to 0.18:

1. The high-ductility self-healing waterproof slurry is filled into the outer side of the backing slurry material in the deformation joint and compacted. The above operation is repeated. The thickness of the high-ductility self-healing waterproof slurry filled each time does not exceed 25mm, and the total thickness of the high-ductility self-healing waterproof slurry is 50mm ± 10mm.

4. The method for repairing leakage at expansion joints in underground utility tunnels according to claim 1 or 3, characterized in that, The high-ductility self-healing waterproof mortar is formulated from P·O 42.5R silicate cement, R·SAC42.5 sulfoaluminate cement, quartz sand, penetrating crystallizing waterproofing agent, polypropylene fiber, redispersible latex powder and polycarboxylate superplasticizer in a mass ratio of 1:2~4:4~6:0.1~0.3:0.01~0.03:0.1~0.3:0.001~0.

005. The quartz sand has a particle size of 0.15~0.6mm and the polypropylene fiber has a length of 6~12mm.

5. The method for repairing leakage at expansion joints in underground utility tunnels according to claim 1, 3, or 4, characterized in that, In step (3), the ratio of the high-ductility self-healing waterproof mortar to water is 1:0.13 to 0.2, the thickness of the high-ductility polymer sealing slurry embedded in the deformation joint is 10 to 20 mm, and the height of the cavity is 100 mm ± 10 mm.

6. The method for repairing leakage at expansion joints in underground utility tunnels according to claim 1 or 5, characterized in that, The high-ductility polymer sealing mortar is formulated from P·O42.5R silicate cement, R·SAC42.5 sulfoaluminate cement, quartz sand, polypropylene fiber, redispersible latex powder, and polycarboxylate superplasticizer in a mass ratio of 1:2~4:4~6:0.01~0.03:0.1~0.3:0.002~0.

01. The quartz sand has a particle size of 0.15~0.6mm, and the polypropylene fiber has a length of 6~12mm.

7. The method for repairing leakage at expansion joints in underground utility tunnels according to claim 1, 3, or 5, characterized in that, In step (4), grouting holes are drilled obliquely at a distance d of 200mm ± 10mm between the concrete inner wall surface on both sides of the expansion joint and the expansion joint to form grouting holes that communicate with the cavity. The angle α between the grouting hole and the inner wall surface of the pipe gallery on the horizontal plane is 30 to 45°, and the diameter of the grouting hole is 10 to 30mm. When drilling obliquely multiple times, the distance between any two grouting holes on the inner wall surface of the pipe gallery is 500 to 1000mm.

8. The method for repairing leakage at expansion joints in underground utility tunnels according to claim 7, characterized in that, Each grouting hole is equipped with a grouting nozzle with a check valve. Silane-modified polyether material is injected into the cavity multiple times from bottom to top through the grouting nozzle, with each injection interval being 10 to 15 minutes.

9. The method for repairing leakage at expansion joints in underground utility tunnels according to claim 1, 3, 5, or 7, characterized in that, In step (5), the W-shaped stainless steel plate has a thickness of 2mm, a width of 30-50mm and a yield strength of not less than 300MPa. The W-shaped stainless steel plate is symmetrically fixed to both sides of the expansion joint by anchors or adhesive.

10. The method for repairing leakage at expansion joints in underground utility tunnels according to claim 9, characterized in that, The polymer waterproof coating is prepared by mixing P·O 42.5R silicate cement, quartz sand, styrene-acrylic emulsion, polypropylene fiber, polyether defoamer, and water in a mass ratio of 42.5:15-25:25-40:0.1-0.5:3-6. The quartz sand has a particle size of 0.15-0.6 mm, the polypropylene fiber has a length of 6-12 mm, and the polymer waterproof coating has a thickness of 2-3 mm, applied in two coats.

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