Deformation joint epoxy resin and polyurethane composite waterproof layer reconstruction method

Abstract

The invention provides a reconstruction method for a deformation joint epoxy resin and polyurethane composite waterproof layer, and aims to overcome the defects in the prior art and improve the waterproof performance of a subway tunnel deformation joint. The method comprises the following steps: removing a decorative layer and electromechanical equipment; drilling an inclined hole and injecting oil-soluble polyurethane slurry to block leakage; grouting epoxy resin at high pressure to form an inner rigid waterproof layer; coating a single-component polyurethane waterproof coating to form an outer flexible waterproof layer; drilling holes, embedding expansion bolts into the holes to fix the externally-pasted rubber water-stop belt, and finally recovering the decorative layer and the electromechanical equipment. Details such as grouting pressure, hole distance, included angle, coating thickness, expansion bolt installation and the like are optimized, a high-performance waterproof material composite structure is adopted, and elasticity, sealing performance, durability and reliability of the waterproof layer are enhanced. According to the scheme, construction is easy and convenient, and an efficient and reliable solution is provided for subway tunnel deformation joint waterproof treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of expansion joints, and specifically to a reconstruction method for a composite waterproof layer of epoxy resin and polyurethane for expansion joints. Background Art

[0002] In the construction of subway tunnels, expansion joints are set to accommodate the expansion and deformation of the structure caused by factors such as temperature changes, foundation settlement, or earthquakes, ensuring the overall stability and safety of the tunnel structure. However, expansion joints are also weak links in the tunnel waterproofing system. Since expansion joints need to withstand frequent displacement and deformation, traditional single waterproof materials or simple plugging processes often fail to meet the long-term waterproofing requirements.

[0003] Currently, methods such as rubber waterstops, grouting plugging, or waterproof coatings are mostly used for waterproof treatment of expansion joints in subway tunnels. However, these methods have many limitations. For example, although rubber waterstops have certain elasticity and sealing properties, they are prone to aging, cracking, or falling off under the action of long-term stress and deformation; although grouting plugging can fill the gaps in the short term, the grout is easy to flow away and it is difficult to form a stable waterproof layer; while waterproof coatings often have limited coating thickness and are difficult to resist the shear force and tensile force at expansion joints.

[0004] Therefore, there is an urgent need for a composite waterproof layer reconstruction method that can comprehensively consider the displacement characteristics of expansion joints, the durability of waterproof materials, and the construction convenience. This application precisely addresses this technical problem and proposes a reconstruction method for a composite waterproof layer of epoxy resin and polyurethane for expansion joints, aiming to improve the waterproof performance and service life of expansion joints in subway tunnels through the combined application of multiple waterproof measures. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the above technical defects and provide a reconstruction method for a composite waterproof layer of epoxy resin and polyurethane for expansion joints, including the following steps: (1) Demolish the decorative layer and mechanical and electrical equipment in the expansion joint area to expose the leakage part; (2) Drill inclined holes on the water-facing side of the expansion joint and inject oil-soluble polyurethane grout for leakage plugging; (3) Inject epoxy resin into the expansion joint through a high-pressure grouting device to form an inner rigid waterproof plugging layer; (4) After the epoxy resin is cured, apply a one-component polyurethane waterproof coating on the surface of the expansion joint to form an outer flexible waterproof layer; (5) Lay a polymer waterproofing membrane outside the outer flexible waterproof layer, weld the lap joints of the membrane by hot air, and install a galvanized steel drainage box on the surface of the membrane, aligning the drainage box with the center line of the expansion joint; (6) Drill holes on both sides of the expansion joint and implant expansion bolts to fix the external rubber waterstop; (7) Restore the decorative layer and mechanical and electrical equipment.

[0006] Preferably, in step (2), the injection pressure of the oil-soluble polyurethane slurry is 0.3 - 0.5 MPa, the spacing between grouting holes is 20 - 30 cm, and the angle between the grouting hole and the center line of the deformation joint is 45° - 60°.

[0007] Preferably, in step (3), the injection depth of the epoxy resin needs to penetrate the old waterproof layer in the original structure joint, and before grouting, an ultrasonic detector is used to locate the position of the existing waterstop belt, and the grouting hole should avoid the waterstop belt by at least 5 cm.

[0008] Preferably, in step (4), the coating thickness of the one-component polyurethane waterproof coating is 2 - 3 mm, it is applied in two cross coats, the interval time between each coat is 4 - 6 hours, and the coating range extends 15 - 20 cm on both sides of the deformation joint.

[0009] Preferably, the installation of the expansion bolts in step (5) includes the following sub-steps: (5a) Use a φ16 drill bit to drill symmetrically on both sides of the deformation joint, the hole depth is 10 - 12 cm, and the hole spacing is 25 - 35 cm; (5b) After cleaning the drill hole, inject the rebar glue and implant a φ14 stainless steel expansion bolt; (5c) After the bolt is fixed, fix the external rubber waterstop belt to the bolt through a pressure plate, and the lap joint of the waterstop belt is welded by hot melting, and the lap length is not less than 10 cm.

[0010] Preferably, before installing the external rubber waterstop belt, a polyurethane waterproof coating needs to be pre-brushed on both sides of the deformation joint, the coating thickness ≥ 3 mm, and the waterstop belt can be installed after the coating is cured.

[0011] Preferably, the polymer waterproofing membrane in step (5) is ethylene propylene diene monomer (EPDM) membrane or thermoplastic polyolefin (TPO) membrane, the welding temperature of the membrane lap joint is controlled at 180 - 220 °C, and the lap width ≥ 10 cm; the thickness of the galvanized steel drainage box is 1.5 - 2 mm, both sides of the box body are fixed to the membrane by rivets, and drainage holes are reserved at the bottom of the box body, the hole diameter is 5 - 8 mm, and the hole spacing is 15 - 20 cm.

[0012] Preferably, the mixing ratio of the epoxy resin in step (3) is epoxy matrix resin: curing agent: toughening agent = 100:30:15 (by weight), and after grouting, an infrared heating device is used to accelerate curing, the curing temperature is 50 - 60 °C, and the curing time ≤ 2 hours.

[0013] Preferably, after the grouting operations in steps (2) and (3) are completed, the plugging effect needs to be verified by a leakage detector. The detection pressure is 0.2 MPa, and the pressure holding time is ≥ 30 minutes without leakage to be qualified.

[0014] Preferably, after the electromechanical equipment is restored in step (6), a 5 - 8 mm expansion joint is reserved at the joint between the decorative layer and the deformation joint. The joint is filled with an elastic sealant, and a nano - hydrophobic coating is applied on the surface of the sealant.

[0015] Compared with the prior art, the advantages of this application are as follows: An innovative waterproof solution for deformation joints in subway tunnels is proposed. This solution comprehensively considers the displacement characteristics of deformation joints, the durability of waterproof materials, and the convenience of construction. By adopting a composite structure of high - performance waterproof materials such as epoxy resin and polyurethane, not only the elasticity and sealing performance of the waterproof layer are effectively improved, enabling it to better adapt to the long - term displacement and deformation of deformation joints, but also the durability and reliability of the waterproof layer are significantly enhanced, extending the service life of subway tunnels. At the same time, this solution is simple in construction and easy to operate, providing a more efficient and reliable solution for the waterproof treatment of deformation joints in subway tunnels. Description of the Drawings

[0016] Figure 1 It is a principle block diagram of a reconstruction method for a composite waterproof layer of epoxy resin and polyurethane for deformation joints in this application. Detailed Embodiments

[0017] The following further elaborates on the present invention with reference to the drawings.

[0018] The following further illustrates the detailed embodiments of the present invention with reference to the drawings. The same components are denoted by the same reference numerals.

[0019] It should be noted that the terms "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to the directions in the drawings, and the terms "inner" and "outer" respectively refer to the directions towards or away from the geometric center of a specific component.

[0020] In order to make the content of the present invention more clearly understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.

[0021] Step (1): Demolish the obstacles in the construction area First, remove the decorative layer (such as tiles, paint layers) and electromechanical equipment (cables, pipes) within 50 cm of the deformation joint area, exposing the leakage points and the surrounding concrete base surface. Use non - destructive cutting technology to demolish the decorative layer to avoid damaging the structure body. After removal, use a high - pressure water gun (pressure ≥ 8 MPa) to wash the base surface, remove loose particles and dry it until the moisture content ≤ 8%.

[0022] Technical effect: Through precise demolition and base surface treatment, a clean and stable construction interface is provided for subsequent grouting operations.

[0023] Step (2): Plugging leakage of inclined hole grouting Drill inclined grouting holes on the water-facing side of the deformation joint (upstream side of the water seepage direction). The spacing of the grouting holes is 25 cm, the drilling diameter is 12 mm, the drilling direction forms an angle of 50° with the center line of the deformation joint (preferred range 45° - 60°), and the drilling depth needs to penetrate the structural layer into the internal cavity of the deformation joint. Use a double-fluid grouting pump to inject oil-soluble polyurethane slurry (specific gravity 1.1 - 1.2 g / cm³), and control the grouting pressure at 0.4 MPa (range 0.3 - 0.5 MPa). After grouting until the slurry overflows from the adjacent hole, keep the pressure for 3 minutes and then stop grouting.

[0024] Key process: The inclined hole design enables the slurry to penetrate reversely along the water seepage channel, forming a root-like plugging body. Experimental data shows (Table 1) that when the angle is 50°, the slurry diffusion radius is increased by 32% compared with vertical drilling.

[0025] Table 1 Influence of different grouting angles on the plugging effect Step (3): Construction of epoxy resin rigid waterproof layer Use an ultrasonic detector to locate the position of the existing water stop belt, ensuring that the distance between the new grouting hole and the edge of the existing water stop belt is ≥ 6 cm (specification requirement ≥ 5 cm). Use high-pressure grouting equipment (pressure ≥ 15 MPa) to inject epoxy resin mixture into the deformation joint. The ratio is: 100 parts of epoxy matrix resin (E-44 type), 30 parts of polyetheramine curing agent, and 15 parts of carboxyl-terminated nitrile rubber toughening agent (by weight). The grouting depth needs to penetrate the original old waterproof layer until the slurry overflows from the back water side of the deformation joint.

[0026] After grouting, use an infrared heating device (wavelength 2.5 - 5 μm) to heat the grouting area to 55°C (range 50 - 60°C) to accelerate the cross-linking and curing of epoxy resin molecules, and the curing time is shortened to 1.5 hours (conventional curing takes 6 hours). After testing, the compressive strength of the epoxy layer after heating and curing reaches 85 MPa, which is 40% higher than that of natural curing.

[0027] Innovation point: Infrared heating promotes the ring-opening polymerization of epoxy groups by exciting molecular vibration energy, forming a dense three-dimensional network structure.

[0028] Step (4): Construction of polyurethane flexible coating After the epoxy resin is cured, apply a one-component polyurethane waterproof coating (solid content ≥ 92%) in two crosswise coats. The first coat has a thickness of 1.2 mm and is applied longitudinally along the deformation joint; the second coat is applied perpendicular to the first coat with a thickness of 1.5 mm, and the total thickness reaches 2.7 mm (range 2 - 3 mm). The application range extends 18 cm (range 15 - 20 cm) on both sides of the deformation joint, and the interval between the two coats is 5 hours (range 4 - 6 hours).

[0029] Technical effect: The cross-coating process eliminates coating pinholes, the tensile strength reaches 3.5 MPa (national standard ≥ 2.5 MPa), and the elongation at break ≥ 450%.

[0030] Step (5): Installation of polymer membrane and drainage system a) Membrane laying Select a 1.5-mm-thick ethylene propylene diene monomer (EPDM) membrane (or TPO membrane), with a lap width of 12 cm (≥ 10 cm). Use a hot air welding machine (temperature 200 °C ± 10 °C) to weld the lap joints, and the weld peel strength ≥ 4 N / mm (GB 18173.1 - 2012).

[0031] b) Installation of galvanized steel drainage box Pre-fabricate a U-shaped drainage box from 1.8-mm-thick galvanized steel, and drill Φ6-mm drainage holes (spacing 18 cm) at the bottom of the box body. Fix the drainage box and the membrane with aluminum rivets, and the deviation of the bottom from the center line of the deformation joint ≤ 3 mm. Experiments show (Table 2) that this structure can increase the leakage drainage efficiency by 90%.

[0032] Table 2 Comparison of drainage efficiency of drainage box Step (6): Double fixation system for waterstop a) Insertion of expansion bolts Use a φ16 drill bit to drill holes (hole depth 11 cm, spacing 30 cm) on both sides of the deformation joint, inject anchor glue (tensile strength ≥ 18 MPa), and then insert φ14 stainless steel expansion bolts. The exposed length of the bolts is 3 cm, and the perpendicularity deviation ≤ 2°.

[0033] b) Installation of waterstop Pre-apply a 3.2-mm-thick polyurethane coating (curing time 8 hours) on both sides of the deformation joint. Fix the externally bonded rubber waterstop (width 30 cm) with galvanized pressing plates and bolts. The lap part of the waterstop is welded by hot melting (lap length 12 cm), and the shear strength at the joint ≥ 5 MPa.

[0034] Synergistic effect: The coating layer fills the micro-cracks on the base surface, and the bolt - pressing plate system provides continuous pressing force to form a mechanical - chemical double seal.

[0035] Step (7): Restoration of construction and strengthening of sealing After the electromechanical equipment is restored, a 6-mm expansion joint (range: 5 - 8 mm) is reserved at the joint of the decorative layer, filled with silicone sealant (displacement capacity ±25%), and a nano-hydrophobic coating (contact angle ≥150°) is applied on the surface. After 500 thermal cycle tests, there are no cracking or debonding phenomena at the joint.

[0036] Quality inspection and acceptance Verification of grouting effect: Apply a water pressure of 0.2 MPa to the blocked areas in steps (2) and (3) using a leakage detector and keep the pressure for 35 minutes without leakage.

[0037] Coating adhesion test: Conduct a cross-cut test on the polyurethane coating, and the adhesion grade reaches Grade 1 specified in GB / T 9286-1998.

[0038] Overall waterproof performance: Conduct a 48-hour water storage test in accordance with GB 50108-2008, and there is no leakage point.

[0039] Summary of technical parameters of the embodiment Through the above implementation, the present invention constructs a four-layer protection system of "rigid grouting layer - flexible coating - coiled material drainage - mechanical water stop", and each material component realizes synergistic effect through molecular bonding (epoxy resin and concrete), physical interlocking (polyurethane coating), and mechanical anchoring (bolt water stop). Experiments show that this method can extend the waterproof life of the deformation joint to more than 15 years, which is 3 times higher than the traditional process.

[0040] The above describes the present invention and its implementation manners. This description is not restrictive, and what is shown in the drawings is only one of the implementation manners of the present invention. The actual structure is not limited thereto. Generally speaking, if those of ordinary skill in the art are inspired by it and design similar structural manners and embodiments without creative efforts without departing from the purpose of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A method for reconstructing a composite waterproof layer of epoxy resin and polyurethane of a deformation joint, characterized in that: The following steps are involved: (1) Remove the decorative layer and electromechanical equipment in the deformation joint area to expose the leakage site; (2) Drilling inclined holes on the water-facing surface of the deformation joint and injecting oil-soluble polyurethane slurry to seal the water leakage; (3) Inject epoxy resin into the deformation joint through high-pressure grouting equipment to form an inner rigid waterproof sealing layer; (4) After the epoxy resin is cured, a single-component polyurethane waterproof coating is applied to the surface of the deformation joint to form an outer flexible waterproof layer; (5) Lay polymer waterproofing membrane outside the outer flexible waterproof layer, use hot air welding for the overlap seams of the membrane, and install a galvanized steel plate drainage box on the surface of the membrane, with the drainage box aligned with the center line of the deformation joint; (6) Drill holes on both sides of the expansion joint and insert expansion bolts to fix the external rubber waterstop; (7) Restore the decorative layer and electromechanical equipment.

2. A method for reconstructing a composite waterproof layer of epoxy resin and polyurethane for expansion joints according to claim 1, characterized in that: The injection pressure of the oil-soluble polyurethane slurry in step (2) is 0.3-0.5 MPa, the spacing between the grouting holes is 20-30 cm, and the angle between the grouting holes and the center line of the deformation joint is 45°-60°.

3. The method for reconstructing the expansion joint epoxy resin and polyurethane composite waterproof layer according to claim 1, characterized in that: The injection depth of the epoxy resin in step (3) needs to penetrate the old waterproof layer in the original structural joint, and an ultrasonic detector needs to be used to locate the position of the existing waterstop before grouting, and the grouting hole needs to be at least 5 cm away from the waterstop.

4. The method for reconstructing a composite waterproof layer of epoxy resin and polyurethane for expansion joints according to claim 1, characterized in that: The coating thickness of the single-component polyurethane waterproof coating in step (4) is 2-3 mm, and it is applied crosswise twice, with an interval of 4-6 hours between each application, and the coating range extends to 15-20 cm on both sides of the deformation joint.

5. The method for reconstructing the expansion joint epoxy resin and polyurethane composite waterproof layer according to claim 1, characterized in that: The installation of the expansion bolts in step (5) includes the following sub-steps: (5a) Use a φ16 drill bit to drill holes symmetrically on both sides of the deformation joint, with a hole depth of 10-12 cm and a hole spacing of 25-35 cm; (5b) After cleaning the drilled hole, inject the anchor glue and insert the φ14 stainless steel expansion bolt; (5c) After the bolts are fixed, fix the external rubber waterstop to the bolts through the pressure plate. The overlap of the waterstop is hot-melt welded, and the overlap length is not less than 10cm.

6. A method for reconstructing a composite waterproof layer of epoxy resin and polyurethane for expansion joints according to claim 5, characterized in that: Before installing the external rubber waterstop, a polyurethane waterproof coating must be pre-coated on both sides of the expansion joint. The coating thickness should be ≥3mm, and the waterstop can be installed only after the coating is cured.

7. The method for reconstructing the expansion joint epoxy resin and polyurethane composite waterproof layer according to claim 5, characterized in that: The polymer waterproofing membrane described in step (5) is an EPDM rubber membrane or a TPO thermoplastic polyolefin membrane, the welding temperature of the membrane overlap seam is controlled at 180-220°C, and the overlap width is ≥10cm; the thickness of the galvanized steel plate drainage box is 1.5-2mm, and the two sides of the box body are fixed to the membrane by rivets, and drainage holes are reserved at the bottom of the box body, with a hole diameter of 5-8mm and a hole spacing of 15-20cm.

8. The method for reconstructing the expansion joint epoxy resin and polyurethane composite waterproof layer according to claim 1, characterized in that: The ratio of the epoxy resin in step (3) is epoxy matrix resin: curing agent: toughening agent = 100:30:15 (weight ratio), and after grouting, infrared heating equipment is used to accelerate curing, the curing temperature is 50-60°C, and the curing time is ≤2 hours.

9. The method for reconstructing the expansion joint epoxy resin and polyurethane composite waterproof layer according to claim 1, characterized in that: After the grouting operation of step (2) and step (3) is completed, the plugging effect needs to be verified by a leakage detector. The detection pressure is 0.2MPa, and the pressure maintenance time is ≥30 minutes without leakage to be qualified.

10. The method for reconstructing the expansion joint epoxy resin and polyurethane composite waterproof layer according to claim 1, characterized in that: After the electromechanical equipment is restored in step (6), a 5-8 mm expansion joint is reserved at the joint between the decorative layer and the deformation joint, the joint is filled with elastic sealant, and the surface of the sealant is coated with a nano-hydrophobic coating.

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