Seepage-proofing treatment method for expansion joint of hydraulic structure

Abstract

The invention discloses an anti-seepage treatment method for an expansion joint of a hydraulic structure structure. The anti-seepage treatment method comprises the following steps that polyurethane grouting material joint filling treatment, polysulfide sealant joint sealing treatment and epoxy plaster surface sealing treatment are sequentially conducted on the water seepage position of the expansion joint of the hydraulic structure structure. Through combination and combination of multifunctional materials and a plurality of repair complete technologies, the expansion joint treatment combined material and process in which the water leakage position is filled with a polyurethane grouting material, the two-component polysulfide sealant is used for caulking and filling of the expansion joint, and the surface of the expansion joint is sealed with the elastic epoxy plaster are structurally formed; the repair characteristics of the grouting material, the caulking filling material and the surface protection material are comprehensively utilized, a reliable expansion joint repair system is established from the structural composition and the material performance, the overall anti-seepage performance of the structural expansion joint is effectively improved, and the service life of a hydraulic structure is prolonged.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of structural expansion joint construction, and particularly relates to a water conservancy structure expansion joint anti-seepage treatment method. BACKGROUND

[0002] In a water conservancy tunnel, a structural expansion joint is a joint set in a concrete structure to adapt to deformation. However, due to repeated action of internal bending moment, shear force, axial tensile stress and axial pressure at the section of the structure, the expansion joint may be aged and failed or deformed beyond the limit of the material, resulting in leakage due to cracking of the structural joint. The structural expansion joint is a weak link in the anti-seepage of the concrete pipeline. Water seepage in the expansion joint not only causes loss of effective water, but also easily forms a concentrated seepage channel to cause instability and deformation of the structure, and even causes collapse of the project. In a severe environment, water seepage causes frost heaving and corrosion of the water conservancy tunnel structure, resulting in damage to the lining structure and serious threat to the safety of the project.

[0003] To adapt to the deformation of the expansion joint and ensure that the expansion joint is not damaged under the action of internal and external water pressure, appropriate joint sealing materials and corresponding technologies need to be selected to achieve the purpose of water sealing and anti-seepage, and to enhance the stability of the water sealing structure and improve the applicability and durability of the materials. In recent years, with the rapid development of anti-seepage engineering technology and the wide application of high molecular materials, high molecular materials such as asphalt mortar, plastic oil paste, polyvinyl chloride cement, tar plastic cement, polyurethane and polysulfide sealant are used as water sealing fillers in the anti-seepage treatment technology of water conservancy tunnel expansion joints at home and abroad. However, these fillers are greatly affected by temperature, have the problems of high-temperature flow, low-temperature brittle cracking, easy aging and environmental pollution, and reduce the reliability and safety of the anti-seepage treatment technology of the expansion joint, affecting the normal function of the water conveyance project.

[0004] Therefore, it is necessary to develop a multi-layer three-dimensional anti-seepage treatment construction method for the structural expansion joint of a water conservancy structure. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a water conservancy structure expansion joint anti-seepage treatment method to solve the technical problem of insufficient water sealing and anti-seepage effect of the existing expansion joint anti-seepage treatment technology.

[0006] To achieve the above-mentioned purpose, the present application realizes the following technical scheme: The present application provides a water conservancy structure expansion joint anti-seepage treatment method, comprising the following steps: sequentially performing polyurethane grouting material joint sealing treatment, polysulfide sealant joint sealing treatment and epoxy cement surface sealing treatment at the water seepage position of the structural expansion joint.

[0007] Preferably, the polyurethane grouting material has a gel time of ≤ 30 s, a water-swelling rate of ≥ 100%, and a foaming rate of 400% to 500%; the polysulfide sealant has a tensile modulus of ≥ 0.3 MPa and an elastic recovery rate of > 80% at 23℃; and the epoxy mortar has a dry bonding strength of > 3 MPa, a wet bonding strength of > 2.5 MPa, and an elongation at break of > 100%.

[0008] Preferably, the polyurethane grouting material is CW531 water-soluble polyurethane grouting material, the polysulfide sealant is CW741 polysulfide sealant, and the epoxy mortar is CW716 elastic epoxy mortar.

[0009] Preferably, the method for preventing seepage of a structural expansion joint of a hydraulic structure specifically comprises the following steps: Hole arrangement: holes are arranged in a seepage area of the structural expansion joint to form grouting holes communicating with the expansion joint; Joint filling: polyurethane grouting material is injected into the grouting holes; Joint sealing: the expansion joint after the joint filling is embedded and filled with polysulfide sealant; Surface sealing: epoxy mortar is coated on the surface of the expansion joint after the joint sealing.

[0010] Preferably, before the holes are arranged in the seepage area of the structural expansion joint, the method further comprises cleaning sundries and dirt on the surface of the expansion joint.

[0011] Preferably, the grouting holes comprise over-joint holes and inclined holes; the grouting holes have a hole diameter of 10 to 20 mm and a hole spacing of 20 to 50 cm.

[0012] Preferably, before the polyurethane grouting material is injected into the grouting holes, the method further comprises pressurizing acetone into the grouting holes.

[0013] Preferably, before the polyurethane grouting material is injected into the grouting holes, the method further comprises flushing the grouting holes and the expansion joint.

[0014] Preferably, the polyurethane grouting material is injected into the grouting holes by using a grouting nozzle embedded in the grouting holes, the grouting nozzle is pulled out after the grouting is completed, and surface hole sealing treatment is performed.

[0015] Preferably, before the embedded joint filling is performed by using the polysulfide sealant, the method further comprises coating a primer on both sides of the expansion joint.

[0016] Preferably, before the epoxy mortar is coated on the surface of the expansion joint after the joint sealing, the method further comprises coating an epoxy resin primer on the surface of the expansion joint after the joint sealing.

[0017] The method has the following advantages: The present application forms a combination material and process for expansion joint treatment by combining multifunctional materials and using multiple repair sets of technology, fills the leaking water with polyurethane grouting material in structure, fills the expansion joint with polysulfide sealant, and seals the surface of the expansion joint with elastic epoxy mortar. The repair characteristics of grouting material, joint filling material and surface protection material are comprehensively used to establish a reliable expansion joint repair system from the aspects of structural composition and material performance, effectively improve the overall anti-seepage performance of the structure expansion joint, and prolong the service life of the hydraulic structure.

[0018] The present application can be used for the anti-seepage treatment of structural joints of concrete water conveying tunnels, concrete box culverts and channels in water diversion projects. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0020] Based on the analysis of the causes of water seepage in structural expansion joints, the present application forms a complete set of combination material and process for expansion joint treatment of various types of concrete water conveying tunnels through the research and development of anti-seepage materials based on the causes of water seepage and the systematic research on adaptive reinforcement technology. Specifically, the present application provides a method for anti-seepage treatment of structural expansion joints of hydraulic structures, comprising the following steps: (1) Hole distribution: clean the dirt and dirt on the surface of the expansion joint, and perform hole distribution, drilling and hole washing in the water seepage area of the structural expansion joint to form grouting holes communicating with the expansion joint; the grouting holes include joint riding holes and inclined holes; the hole diameter of the grouting hole is 10-20 mm, and the hole spacing is 20-50 cm.

[0021] (2) Joint filling: embed the grouting nozzle into the grouting hole, and flush the grouting hole and the expansion joint. Then, pressurize acetone into the grouting hole, calculate the volume of the joint by the amount of pressed acetone, and use it as a reference for determining the grouting amount. Acetone is volatile and can effectively combine with water to form a mixture, which can displace the residual water in the hole, ensuring that the grout effectively plays a plugging and reinforcing effect in the joint during grouting. According to the crack condition, grouting hole inspection record and acetone pressurization test result, the amount of grout and grouting pressure are determined. Start the grouting pump to inject polyurethane grouting material into the grouting hole. After grouting, pull out the grouting nozzle and perform surface hole sealing treatment.

[0022] (3) Joint sealing: coat a primer on both sides of the expansion joint, and after the primer solidifies, use polysulfide sealant to fill the expansion joint after joint filling treatment.

[0023] (4) Surface sealing: After the sealing treatment of the expansion joint, the surface of the expansion joint is coated with epoxy primer, and after the primer is solidified, epoxy mortar is coated.

[0024] The expansion joint anti-seepage treatment material is required to have strong adhesion, good anti-seepage effect, strong deformation adaptability, long service life, certain water pressure resistance, green environmental protection, and simple construction. In some preferred embodiments, the gel time of the polyurethane grouting material is ≤30 s, the water swelling rate is ≥100%, and the foaming rate is 400%-500%; the tensile modulus of the polysulfide sealant at 23°C is ≥0.3 MPa, and the elastic recovery rate is >80%; the dry adhesion strength of the epoxy mortar is >3 MPa, the wet adhesion strength is >2.5 MPa, and the elongation at break is >100%. Further, in some preferred embodiments, the polyurethane grouting material is CW531 water-soluble polyurethane grouting material; the polysulfide sealant is CW741 polysulfide sealant; and the epoxy mortar is CW716 elastic epoxy mortar.

[0025] The water conservancy structure expansion joint treatment process provided by the application forms a multi-layer three-dimensional anti-seepage combination system at the structure level through polyurethane grouting repair-polysulfide sealant sealing-high elasticity epoxy mortar surface sealing. First, the polyurethane grouting material is used to drill and grout the water seepage part of the structure joint. This material has strong water quality adaptability and can form an elastic solidified body in a water environment with a pH of 4.0-12.0. The slurry has secondary permeability, and the carbon dioxide gas pressure released during the formation of the solidified body further presses the slurry into the joint gap to fill and compact, thereby achieving a fast and efficient water stopping effect on the expansion joint leakage part. In addition, the elastic solidified body has good extensibility, low temperature resistance, and non-flammability, and is environmentally friendly and non-toxic, facilitating construction. After anti-seepage treatment, polysulfide sealant is used for further sealing treatment. This material is a new type of non-toxic waterproof sealing material made of liquid polysulfide rubber as the main material and various chemical additives through high polymer material synthesis process, and has the characteristics of good sealing performance, high adhesion strength, good elasticity, and long service life, and can resist the damage of internal and external water pressure to the expansion joint. Finally, high elasticity epoxy mortar is used for surface sealing. A flexible material with high elongation at break is selected to prevent surface defects caused by repeated tensioning of the expansion joint from occurring and developing, thereby affecting the working efficiency of the internal anti-seepage body, thereby avoiding the initiation of structural aging damage from the inside out, which is beneficial to the long-term service of the water conveying tunnel expansion joint.

[0026] Embodiment A water conservancy structure expansion joint anti-seepage treatment method, comprising the following steps: (1) Polyurethane grouting repair of expansion joint Preparation. Check the leakage of the expansion joint and mark the leakage points. Clean the surface of the expansion joint of dirt and ensure that the grouting area is dry and free of oil.

[0027] Drilling. The holes are drilled by using a combination of riding seam holes and inclined holes. The grouting hole diameter is 14 mm, the riding seam hole depth is 15 cm, the inclination of the inclined hole is 30°, and the hole depth is controlled by passing through the crack by 10 cm. The drilling distance is 20 cm.

[0028] Washing the hole. After drilling, the hole is washed clean of powder and debris using an air compressor or a pressure spray gun to clear the channel formed by the drilling and the crack.

[0029] Buried grouting nozzle. A special high-pressure water stop needle is used, which is automatically inflated and sealed by screwing. The needle uses ring pressure fastening principle, and the head is equipped with a one-way check valve to prevent backflow of grout under high pressure. The ring pressure expansion part is made of rubber sleeve, which is inserted into the grouting hole and tightened with ring pressure bolts to compress the rubber sleeve and fix the grouting nozzle in the grouting hole.

[0030] Pressing acetone. The drilling and cracks are flushed with pressure water to check whether the cracks and grouting nozzles are connected, observe the crack sealing condition and leakage around the grouting nozzle. Before grouting, acetone is injected into each hole to calculate the volume of the crack, which is used as a reference for determining the grouting amount. Acetone is volatile and can effectively form a mixture with water, replacing the residual moisture in the hole to ensure that the grout effectively plays a plugging and reinforcing effect in the crack during grouting.

[0031] Grouting. According to the crack condition on site, the grouting hole inspection record and the test results of acetone injection, the amount of grout and grouting pressure are determined. Start the grouting pump and use instant point type grouting. The pressure spreads to all directions, and the CW531 water-soluble polyurethane grouting material is injected into the expansion joint through the grouting pipe to ensure that the grout effectively fills the concrete micro-cracks and micro-pores until the grout overflows from the adjacent hole. The overflow grout on the surface of the crack is sprayed with water to make it solidify and seal the crack.

[0032] Sealing the hole. After the whole grouting is completed, the grouting needle is pulled out, the overflow grout on the working surface is removed, and the needle hole is filled and compacted with high-strength waterproof sealing material. The surface is restored to its original state.

[0033] The performance of CW531 water-soluble polyurethane grouting material is shown in Table 1: Table 1

[0034] (2) Polythiourethane sealant sealing Preparation. Clean the expansion joint of debris, dust and water to ensure that the surface of the expansion joint is dry and clean. Check whether the packaging of CW741 new polythiourethane sealant is intact to ensure that the sealant material is effective. Prepare the glue gun, spatula, cleaning cloth and other tools.

[0035] Priming. Apply the special primer for polyurethane sealant evenly on both sides of the expansion joint, which is made of polyurethane rubber and curing agent, to enhance the adhesion of the sealant to the concrete surface. Wait for 20-30 minutes for the primer to dry before filling the sealant.

[0036] Sealant filling. Mix the two components of the new CW741 polyurethane sealant thoroughly, and use a gun to inject the sealant into the expansion joint at the required depth. Use a curved scraper to smooth the surface of the sealant, making the joint surface a crescent shape. After curing, the surface of the glue is smooth and flat without bubbles, the inside of the glue is dense without broken ends, and the adhesion is firm without delamination, cracking, or water seepage.

[0037] The performance of the new CW741 polyurethane sealant is shown in Table 2: Table 2

[0038] (3) High elasticity epoxy mortar surface sealing Preparation. Clean the expansion joint base (including the CW741 new polyurethane sealant sealing area), remove oil stains, dust, rust, and other impurities, and use sandpaper and an angle grinder to polish the base to ensure no protrusions, holes, or other defects. Check that the CW716 high elasticity epoxy mortar A and B components are in good condition and within the valid period. Prepare the corresponding stirring tools, scrapers, and mixing barrels. Pour the CW716 high elasticity epoxy mortar A and B components into the mixing barrel according to the mass ratio of 10:3, and use the stirrer to mix thoroughly until the A and B components are completely mixed and uniform, forming a glue-like material without bubbles or particles.

[0039] Primer application. Apply a layer of epoxy primer on the expansion joint base (including the CW741 new polyurethane sealant sealing area) to enhance the adhesion of the epoxy mortar to the base.

[0040] Epoxy mortar sealing. After the primer layer is initially cured, use a scraper to evenly apply the CW716 high elasticity epoxy mortar on top of the primer layer, forming a continuous coating with a thickness of about 3mm. During the application process, ensure that the coating surface is smooth and free of bubbles, cracks, and other defects. For difficult-to-construct areas such as corners and edges of the expansion joint, use brushes and other tools to assist in application to ensure complete coverage of the coating.

[0041] Curing and maintenance. After the coating is completed, keep the construction area dry and ventilated until the coating is completely cured. During the curing period, maintain the coating to avoid chemical attacks or mechanical damage, which may affect the curing effect.

[0042] The performance of the CW716 elastic epoxy mortar is shown in Table 3: Table 3

[0043] Performance test (1) Integrity, density and compressive strength Fourteen days after the multi-layer three-dimensional anti-seepage treatment of the structural expansion joint of the hydraulic structure, core samples were taken near the expansion joint to ensure the reliability of the treatment effect. A total of 6 core samples with a diameter of 146 mm were taken, divided into two groups. The first group: 3 core samples with a length of 80 cm, aimed at comprehensively evaluating the anti-seepage effect after grouting treatment by observing the integrity and density of these core samples, and whether the cracks are completely filled with slurry. The second group: 3 core samples with a length of 30 cm, aimed at quantitatively analyzing the strength performance of the grouting material by testing the compressive strength of this group of core samples, and verifying the actual strength effect.

[0044] (2) Water pressure test Fourteen days after the multi-layer three-dimensional anti-seepage treatment of the structural expansion joint of the hydraulic structure, inspection holes were arranged, and the hole position and number were in accordance with the requirements of DL / T 5406-2019 "Technical Code for Chemical Grouting of Hydropower and Water Conservancy Engineering". The inspection standard takes the water permeability rate of the test section as the main evaluation basis, and uses the single-point method to test in sections. The water pressure test is carried out at a design pressure of 0.2 MPa, and the pressure-in flow is measured every 5 minutes. When the difference between the maximum and minimum values of 4 consecutive readings is less than 10% of the final value, or the difference between the maximum and minimum values of 4 consecutive readings is less than 1 L / min, the water pressure test can be completed, and the final value is taken as the calculation value. Any unit water permeability rate greater than 1 Lu is unqualified.

[0045] (3) Adhesion performance test Twenty-eight days after the multi-layer three-dimensional anti-seepage treatment of the structural expansion joint of the hydraulic structure, 6 closed points were selected as adhesion performance test points for pull-out test in each expansion joint to test the adhesion strength between the high-elasticity epoxy mortar and the concrete base surface. Before pulling, ensure that the surface of the epoxy mortar is clean, dry, free of oil stains, dust and other impurities, and polish it with an angle grinder. In the pull-out test, a 20 mm diameter spindle is selected, and AB glue is evenly applied on the spindle and the test base surface, respectively, and then the spindle and the test base surface are tightly bonded. After the adhesion is firm, a cutting device is used to separate the test point from the surrounding consolidated glue and mortar to isolate the test area. Then a pull-out tester is used to perform the pull-out test, and the peak value of the pulling force in the pull-out test is recorded. The ratio of the peak value of the pulling force to the adhesion area is the adhesion strength. The average adhesion strength of all test points is taken as the final adhesion performance index.

[0046] The test results are shown in Table 4:

[0047] As shown in Table 4, after the polyurethane grouting repair, the new polysulfide sealant sealing, and the high-elasticity epoxy mortar surface sealing, the core sample near the expansion joint has good completeness and compactness, and has high compressive strength, indicating that the crack is completely filled with the slurry, and has good anti-seepage effect. After the multi-layer three-dimensional anti-seepage treatment, the water permeability is reduced, the surface sealing layer has high bonding strength, can effectively resist the damage of the internal and external water pressure to the expansion joint, and is beneficial to the long-term service of the water conveying tunnel expansion joint.

[0048] It should be noted that each of the above embodiments belongs to the same inventive concept, and the description of each embodiment has its own emphasis. If the description is not exhaustive in individual embodiments, the description in other embodiments can be referred to.

[0049] The above-described embodiments only express the implementation of the present application, and the description is more specific and detailed, but it should not be construed as limiting the scope of the patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of protection of the present application patent should be subject to the appended claims.

Claims

1. A method for anti-seepage treatment of expansion joints of hydraulic structures, characterized in that: The following steps are involved: At the water seepage areas of expansion joints of hydraulic structures, polyurethane grouting materials are used for filling the joints, polysulfide sealant for sealing the joints and epoxy putty for surface sealing.

2. The anti-seepage treatment method for expansion joints of hydraulic structures according to claim 1, characterized in that: The polyurethane grouting material has a gel time of ≤30s, a water expansion rate of ≥100%, and a foaming rate of 400% to 500%; The polysulfide sealant has a tensile modulus of ≥0.3 MPa at 23°C and an elastic recovery rate of >80%; The epoxy mortar has a dry bonding strength greater than 3 MPa, a wet bonding strength greater than 2.5 MPa, and an elongation at break greater than 100%.

3. The anti-seepage treatment method for expansion joints of hydraulic structures according to claim 2, characterized in that: The polyurethane grouting material is CW531 water-soluble polyurethane grouting material; the polysulfide sealant is CW741 polysulfide sealant; and the epoxy putty is CW716 elastic epoxy putty.

4. The anti-seepage treatment method for expansion joints of hydraulic structures according to claim 1, characterized in that: The following steps are involved: Hole arrangement: Holes are arranged in the water seepage area of ​​the structural expansion joint to form grouting holes connected to the expansion joint; Filling: injecting polyurethane grouting material into the grouting hole; Sealing: Use polysulfide sealant to fill the expansion joints after caulking treatment; Surface sealing: Apply epoxy putty on the surface of the expansion joint after sealing treatment.

5. The anti-seepage treatment method for expansion joints of hydraulic structures according to claim 4, characterized in that: The grouting holes include seam holes and inclined holes; the diameter of the grouting holes is 10-20 mm, and the hole spacing is 20-50 cm.

6. The anti-seepage treatment method for expansion joints of hydraulic structures according to claim 4, characterized in that: Before injecting the polyurethane grouting material into the grouting hole, the method further includes injecting acetone into the grouting hole.

7. The anti-seepage treatment method for expansion joints of hydraulic structures according to claim 4, characterized in that: Before injecting the polyurethane grouting material into the grouting hole, the method further includes flushing the grouting hole and the expansion joint.

8. The anti-seepage treatment method for expansion joints of hydraulic structures according to claim 4, characterized in that: The polyurethane grouting material is injected into the grouting hole by using a grouting nozzle pre-buried in the grouting hole. After the grouting is completed, the grouting nozzle is pulled out and the surface is sealed.

9. The anti-seepage treatment method for expansion joints of hydraulic structures according to claim 4, characterized in that: Before the polysulfide sealant is used for caulking and filling, a primer is applied on both sides of the expansion joint.

10. The anti-seepage treatment method for expansion joints of hydraulic structures according to claim 4, characterized in that: Before coating the epoxy putty on the surface of the expansion joint after the sealing treatment, the method further comprises coating the expansion joint surface after the sealing treatment with an epoxy resin primer.

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