A gradient self-repairing composite waterproof film with bionic tongue-and-groove and a repairing method thereof

Abstract

The application discloses a kind of bionic concave-convex tenon gradient self-repairing composite waterproof membrane and its repair method, belong to underground engineering waterproof technical field.Composite waterproof membrane is three-layer gradient composite integrated structure, including base layer, bionic self-repairing layer and anti-permeation protective layer;The lower surface of base layer is integrally formed with staggered arrangement bionic concave-convex tenon structure, and self-repairing layer is dispersed with microcapsule self-repairing system and fluorosilane modified nanometer silicon dioxide active component.In matching ground penetrating radar linkage intelligent grouting repair method, damaged position is accurately positioned by three-dimensional ground penetrating radar, and two-component slurry is injected into damaged area by high-pressure intelligent grouting, and membrane body repair and soil consolidation are completed synchronously.The application realizes the change of underground engineering waterproof from passive leakage stopping to active defense and intelligent repair, has the characteristics of self-repairing reliable, positioning accurate, repair and reinforcement integration and green construction, and is suitable for waterproofing and repair of water-rich soft soil underground facilities.

Description

Technical Field

[0001] This invention belongs to the field of underground engineering construction technology, specifically, it relates to a biomimetic tenon-and-groove gradient self-healing composite waterproof membrane and its repair method. Background Technology

[0002] With the continuous acceleration of urban renewal in my country, the scale of underground space development and utilization is constantly expanding, leading to a growing demand for underground facilities under complex geological conditions such as water-rich soft soil strata and floodplain strata. However, these strata are characterized by abundant groundwater, poor soil stability, and large settlement deformation, placing extremely high demands on waterproofing technology for underground engineering.

[0003] Traditional waterproofing for underground engineering projects often uses single-material modified HDPE waterproof membranes or SBS modified bitumen waterproof membranes, which have the following prominent problems: First, the waterproof material has poor adhesion to the soil, making it prone to peeling and damage due to soil settlement and groundwater pressure; second, it lacks self-healing ability, and tiny cracks cannot heal on their own, easily developing into leakage channels with long-term use; third, it is difficult to locate the damage point, requiring large-area excavation for repair, resulting in long construction periods, high costs, and unreliable repair results; fourth, traditional repairs are mostly passive sealing, failing to fundamentally solve the leakage problem, and prone to repeated leakage in the later stages.

[0004] While existing self-healing waterproofing technologies have been researched to some extent, they still suffer from shortcomings such as low repair efficiency, poor adaptability, and insufficient intelligence, making it difficult to meet the long-term waterproofing needs of underground facilities in water-rich soft soil strata. Therefore, developing a new waterproofing technology system with active defense, autonomous repair, intelligent detection, and precise repair functions has become a key technical problem that urgently needs to be solved in the field of urban renewal underground engineering construction. Summary of the Invention

[0005] When constructing underground engineering projects on water-rich soft soil sites, waterproofing structures generally suffer from practical problems such as easy damage, difficulty in repair, and limited service life. To address these engineering pain points, this invention develops a biomimetic tenon-and-groove gradient self-healing composite waterproof membrane suitable for water-rich soft soil strata, along with a matching ground-penetrating radar-linked intelligent grouting repair process.

[0006] The objective of this invention can be achieved through the following technical solutions: A biomimetic tongue-and-groove gradient self-healing composite waterproof membrane adopts a three-layer gradient composite structure, including a base layer, a biomimetic self-healing layer, and an anti-seepage protective layer.

[0007] As a further technical solution, the base layer has a long sheet structure, the material is modified high-density polyethylene (HDPE), and the thickness is 1.5 mm.

[0008] As a further technical solution, the modified high-density polyethylene is obtained by mixing and extruding high-density polyethylene resin, toughening agent and antioxidant in a mass ratio of 100:8:1, with a base layer thickness of 1.5 mm.

[0009] The base layer serves as the main substrate of the waterproof membrane. It is a long, sheet-like structure made of modified HDPE material and acts as the primary load-bearing structure, possessing excellent tensile strength, elongation at break, and puncture resistance. Its lower surface directly contacts the water-rich soft soil layer, while its upper surface is tightly bonded to the biomimetic self-healing layer, achieving a multi-layered integrated structure.

[0010] As a further technical solution, the lower surface of the base layer is a biomimetic tenon and mortise structure with staggered arrangement. This structure is an integrated molding structure with imitation wood tenon and mortise interlocking. The whole is in the shape of an inverted frustum tenon with no splicing gaps. All the tenons are arranged in a staggered and even arrangement in a plum blossom shape. Compared with the matrix arrangement, it can improve the interlocking and bonding effect with the soil in all aspects.

[0011] As a further technical solution, the height of a single tenon in the biomimetic mortise and tenon structure is 5-8mm, and the distance between adjacent tenons is 10-15mm.

[0012] The biomimetic tongue and groove structure is integrally formed on the lower surface of the foundation layer. This structure can significantly improve the adhesion and pull-out resistance of the waterproof membrane to the soil, effectively avoiding membrane delamination and peeling caused by soil settlement and stratum deformation.

[0013] As a further technical solution, the biomimetic self-healing layer is made by mixing epoxy resin, microcapsules, fluorosilane-modified nano silica and curing agent in a mass ratio of 100:10:4:12 and applying the mixture by scraping, with a coating thickness of 1.0 mm.

[0014] As a further technical solution, the microcapsules have a particle size of 50-100 μm.

[0015] The function of the biomimetic self-healing layer is as follows: it is uniformly covered on the upper surface of the base layer and is the core functional layer of the waterproof membrane. When the waterproof membrane is subjected to stress and micro-cracks are generated, the microcapsules at the damaged location rupture and release repair components. The repair material reacts with the nano-active ingredients, automatically fills and closes the cracks, realizes micro-damage self-repair, and blocks leakage channels.

[0016] As a further technical solution, the impermeable protective layer is made by spraying a mixture of polyurethane modified epoxy resin and curing agent at a mass ratio of 100:15, with a coating thickness of 0.8 mm.

[0017] As a further technical solution, the thickness of the impermeable protective layer is 0.5-1.0 mm.

[0018] The function of the impermeable protective layer is as follows: it is coated on the outside of the biomimetic self-healing layer and is the outermost protective structure of the waterproof membrane. It adopts a polyurethane modified epoxy resin corrosion-resistant elastic coating, which has multiple functions such as waterproofing, corrosion resistance and anti-aging, and can resist groundwater erosion and external environmental damage.

[0019] As a further technical solution, the edge of the biomimetic tongue and groove gradient self-healing composite waterproof membrane is provided with a sealing overlap groove, and the overlap width is 100-150mm.

[0020] The purpose of the overlap groove is to effectively improve the overall impermeability of the waterproof membrane and ensure the sealing reliability of the splicing position by using a double sealing process of hot melt welding and sealant during construction.

[0021] This invention also provides a repair method for a biomimetic tongue-and-groove gradient self-healing composite waterproof membrane, comprising the following steps: A1. When the waterproof membrane is damaged, a three-dimensional ground-penetrating radar is used to scan the waterproof operation area. Through damage identification and positioning algorithms, the location, size, crack shape and leakage degree of the waterproof membrane damage are determined, and a complete three-dimensional distribution data model of the damaged area is generated. A2. Based on the three-dimensional distribution data model of the damaged area, grouting holes are arranged around the damaged point; A3. High-pressure intelligent grouting equipment is used to inject grout into the damaged area and surrounding soil through micro-hole grouting process to fully fill the gaps in the waterproof membrane, while reinforcing the surrounding loose soil layer and improving the overall density of the stratum. A4. After grouting is completed, leave the area in place for 24 hours to allow the grout to fully hydrate and solidify, ensuring that the damaged waterproof membrane is firmly bonded and the surrounding soil is completely consolidated. Use three-dimensional ground-penetrating radar to scan the repair area again to test and verify the repair and soil reinforcement effects. Once the repair quality is confirmed to be up to standard, the repair is completed.

[0022] As a further technical solution, the positioning accuracy of the damage identification is within ±5cm.

[0023] As a further technical solution, the grouting holes are arranged 1.0-1.5m outside the damaged point, with a spacing of 0.8-1.0m and a diameter of 50-60mm. The grouting holes penetrate the waterproof membrane and extend 0.5-1.0m into the underlying soil layer.

[0024] As a further technical solution, the slurry is obtained by mixing the following raw materials in the following mass ratio: modified polyurethane prepolymer: silicate cement: water: water-reducing agent = 40:60:25:0.5.

[0025] As a further technical solution, the grouting process has a pressure of 0.3-0.5 MPa and a grouting speed of 5-10 L / min.

[0026] The beneficial effects of this invention are: Advantage 1: This invention constructs a three-layer gradient composite integrated molding structure. Each functional layer complements the others and works synergistically. The base layer provides high-strength load-bearing support, the self-healing layer provides active repair capabilities, and the protective layer provides impermeability and corrosion resistance, forming a complete waterproof barrier that combines rigidity and flexibility. The biomimetic tongue-and-groove structure significantly improves the adhesion and pull-out resistance of the waterproof membrane to soft soil layers, effectively preventing membrane delamination due to soil settlement or water pressure, fundamentally solving the persistent problems of poor adhesion and easy damage of traditional roll materials to the soil. Advantage 2: The microcapsules uniformly distributed in the self-repair layer of this invention are combined with fluorosilane-modified nano-silica to form an intelligent response system. When microcracks occur in the waterproof membrane, the microcapsules automatically rupture and release the repair components. Under the catalysis and promotion of the nano-active ingredients, the cracks are quickly filled and closed, realizing the autonomous repair of damage. This transforms the traditional passive sealing into active defense, significantly delaying the aging and failure process of the waterproof layer and extending the service life of underground engineering. Advantage 3: This invention uses three-dimensional ground-penetrating radar full-domain scanning combined with intelligent recognition algorithms to accurately determine the location of waterproof membrane damage, crack morphology and leakage degree, and generate a three-dimensional distribution model of the damaged area. The detection accuracy meets the requirements of precise repair, which changes the extensive operation mode of traditional waterproofing projects that relies on experience for blind exploration and large-area excavation to find leaks, and greatly reduces the waste of resources caused by ineffective excavation and blind grouting. Fourthly, this invention uses a radar 3D model to precisely drill holes around the damaged point. The grouting liquid repairs the cracks in the waterproof membrane while simultaneously diffusing and penetrating into the surrounding soil, consolidating the loose strata into a dense overall structure. This completes both membrane repair and foundation reinforcement in one go, eliminating the conditions for repeated leakage at the source and avoiding the vicious cycle of traditional repair methods.

[0027] Fifthly, the waterproof membrane of this invention is produced in a standardized prefabrication process in a factory. On-site installation is only required, simplifying the process and increasing efficiency. All grouting repairs are completed on the surface, eliminating the need for large-scale excavation of the original soil structure. The construction process does not generate dust, toxic emissions, or other environmental pollutants, meeting the requirements of green construction. It is especially suitable for the rapid repair of underground facilities already in operation in urban built-up areas with water, and has good social benefits and environmental adaptability.

[0028] Therefore, this invention can be widely applied to waterproofing projects for various underground facilities in water-rich soft soil strata and floodplain strata during urban renewal, and has significant economic, social and environmental benefits, with broad market application prospects. Attached Figure Description

[0029] The invention will now be further described with reference to the accompanying drawings.

[0030] Figure 1This is a schematic diagram of the overall structure of the biomimetic tenon-and-groove gradient self-healing composite waterproof membrane prepared in Embodiment 1 of the present invention.

[0031] Figure 2 This is a flowchart illustrating the entire process of the repair method for the biomimetic tongue-and-groove gradient self-healing composite waterproof membrane prepared in Embodiment 1 of the present invention. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1

[0034] according to Figure 1 The schematic diagram shown illustrates the fabrication of a biomimetic tenon-and-groove gradient self-healing composite waterproof membrane: S1. First, add 100 parts of high-density polyethylene resin, 8 parts of toughening agent (POE polyolefin elastomer, model LG Chem LC100), and 1 part of antioxidant (model BASF Irganox 1010) to a high-speed mixer to ensure thorough mixing. Then, feed the mixture into a twin-screw extruder. Set the extrusion temperature sequentially from the feeding section to the die head: feeding section 180℃, melting section 210℃, homogenization section 220℃, and die head 230℃. The sheet is extruded through a T-die to form a continuous sheet with a thickness of 1.5mm. While still hot, the sheet is fed into a die with biomimetic uneven surfaces. The cooling calendering roller assembly for the tenon-forming recesses consists of an upper roller with a polished mirror finish (temperature 80℃) and a lower roller with evenly distributed recesses (temperature controlled at 60℃, with cooling water circulating inside). The recesses on the embossing roller are frustoconical, with a pit diameter (corresponding to the top of the tenon) of 2.5mm, a pit bottom diameter (corresponding to the root of the tenon) of 4.5mm, and a pit depth of 6.5mm. The recesses are arranged in a staggered, quincunx pattern, with a longitudinal spacing of 12mm between adjacent recesses and a transverse spacing of 12mm. The longitudinal rows are staggered by 6mm (half the spacing) along the film's travel direction. Under a linear pressure of 0.8MPa from the calendering roller assembly, the lower surface of the HDPE sheet is pressed into the recesses to form a biomimetic tenon and mortise, simultaneously completing the base layer thickness setting and tenon / mortise formation. The embossed sheet is then gradually cooled to room temperature by three sets of cooling rollers, and then wound up to obtain a base layer with a biomimetic tenon / mortise structure. S2. Mix 100 parts epoxy resin, 4 parts fluorosilane-modified nano silica and 12 parts 2-ethyl-4-methylimidazole at 1000 r / min for 10 min to ensure uniform dispersion of nanoparticles. Then add 10 parts microcapsules (the microcapsules are urea-formaldehyde resin-coated repair agent microcapsules, model Shandong Luyan New Materials LY-W80, with a particle size of 100 μm) and stir at 500 r / min for 5 min to obtain a self-healing layer coating slurry. Use a comma-shaped doctor blade coater to evenly coat the above slurry onto the upper surface of the base layer containing the biomimetic tenon and mortise structure. The wet film thickness is 1.0 mm. After drying and curing, a biomimetic self-healing layer is formed. S3. Mix 100 parts of polyurethane modified epoxy resin (model Shanghai Hans Chemical HS-828) and 15 parts of curing agent (model Aradur 2965) to prepare a protective layer coating slurry. Use a slot extrusion coating method to evenly coat the protective layer slurry onto the upper surface of the biomimetic self-healing layer. Curing is carried out at 80℃ to form a final dry film thickness of 0.8mm, forming an impermeable protective layer. The cured composite film is wound up by a traction roller, and the edges are trimmed by online edge trimming devices on both sides of the film to form a 120mm wide sealing overlap area. S4. Using a heating molding device, two parallel grooves (groove width 8mm, groove depth 1.5mm, and groove spacing 10mm) are pressed in the sealing overlap area along the long side of the waterproof membrane to form a sealing overlap groove structure. The overlap groove is used to fill the sealant during construction and forms a double seal with hot melt welding. After cutting, rolling, and packaging, a biomimetic tongue and groove gradient self-healing composite waterproof membrane is obtained.

[0035] Example 2

[0036] according to Figure 2 The flowchart shown illustrates the entire repair process for repairing the biomimetic tongue-and-groove gradient self-healing composite waterproof membrane. The specific steps are as follows: Step 1: When the waterproof membrane is damaged, use a three-dimensional ground-penetrating radar to scan the entire waterproof membrane area at a constant speed and continuously. The scanning interval is set to 0.5m. The positioning accuracy of the damage point is controlled within ±5cm. The reflected signals of the stratum and waterproof layer are collected in a comprehensive manner, and the basic data of the area are recorded completely. Step 2: After the radar scan is completed, the optimized back projection algorithm analyzes and processes the radar scan data to identify the location of the damage to the waterproof membrane and the degree of leakage. The identification accuracy is within ±3cm, and the three-dimensional spatial coordinates of each damage point are output. Step 3: Based on the identification results, establish a three-dimensional distribution data model of the damaged area, and mark the location, size and leakage level of each damaged point on the distribution map as the design basis for the subsequent grouting hole layout. Step 4: Based on the 3D distribution data model of the damaged area, accurately mark the grouting hole locations on the ground. All grouting holes should be arranged within a 1.0m reinforcement range around the damaged area. Use professional drilling equipment for vertical drilling, controlling the following parameters: hole diameter 55mm, maintaining verticality throughout the drilling process. Drilling depth requirement: vertically penetrate the three-layer composite waterproof membrane and continue drilling down to the underlying soft soil layer for 0.7m. After each hole is drilled, promptly clean out any debris, water, and loose soil from the hole; verify the hole location, diameter, and depth for each hole. Only after all parameters have passed inspection can the grouting process begin. The spacing between adjacent grouting holes should be uniformly controlled at 1.0m. Step 5: Mix 40 parts of modified polyurethane prepolymer (model Shandong Keda Julong JZ-200 hydrophilic modified polyurethane prepolymer), 60 parts of silicate cement, 25 parts of water and 0.5 parts of water-reducing agent, and stir until the slurry is uniform, free of lumps and has the workability standard. The slurry should be prepared and used immediately to avoid long-term static solidification. Step 6: Connect the grout delivery pipeline of the high-pressure intelligent grouting equipment to the grouting hole in a sealed manner, and ensure proper sealing of the hole opening to prevent grout leakage during the grouting process. Start the grouting equipment and monitor the pressure and flow rate in real time throughout the process: maintain the grouting pressure at a stable 0.4 MPa and the grouting speed at 8 L / min. Under pressure, the grout seeps into the cracks in the waterproof membrane and simultaneously diffuses into the surrounding soil, filling the voids in the soil layer. When uniform grout overflows around the grouting hole opening, it indicates that the hole is fully grouted and the voids are filled; stop grouting immediately. Use a special sealing material to tightly seal the grouting hole, and then repeat the above grouting operation for the remaining grouting holes in sequence until all holes are completed. Step 7: After grouting is completed, leave the grout in place for 24 hours to allow the grout to fully hydrate and solidify, ensuring that the damaged parts of the waterproof membrane are firmly bonded and the surrounding soil is completely consolidated. Step 8: Use 3D ground-penetrating radar to scan the repair area again, compare the radar data and 3D model before and after, and verify the repair effect of the waterproof membrane and the change in the density of the stratum. If the detection finds that there are still potential leakage risks or areas that are not reinforced to the standard, follow the process of steps 4 to 8 to relocate and add grouting holes and carry out supplementary grouting. Repeat the detection and grouting until all defects are completely eliminated.

[0037] Step 9: After confirming that the repair quality is qualified, dismantle the construction equipment, clean up the waste and residual grout on site, restore the site to its original appearance, and complete the entire repair process. After confirming that the repair quality is qualified, the repair is completed.

[0038] Comparative Example 1 It uses a traditional single-layer HDPE waterproof membrane (without biomimetic tongue and groove, self-healing layer, or protective layer), with a thickness of 2.5mm, and the material is ordinary HDPE (unmodified).

[0039] Comparative Example 2 A double-layer composite membrane (base layer and self-healing layer, but without biomimetic tongue and groove structure and without anti-seepage protective layer) is adopted. The base layer is modified HDPE (same as in Example 1), and the self-healing layer formula is the same as in Example 1. The total thickness is 2.5mm.

[0040] The following performance tests were conducted on Example 1 and Comparative Examples 1 and 2: Tensile strength was determined according to GB / T 328.9 standard; The maximum impermeable pressure was determined according to GB / T 328.10 standard; The measurement results are shown in Table 1: Table 1

[0041] As can be seen from the test results in Table 1, the waterproof membrane prepared by the embodiment of the present invention has higher tensile strength and impermeability than the comparative example. Therefore, the present invention can be widely used in waterproofing projects of various underground facilities in water-rich soft soil strata and floodplain strata in urban renewal, with significant economic, social and environmental benefits and broad market application prospects.

[0042] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0043] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A biomimetic tongue-and-groove gradient self-healing composite waterproof membrane, characterized in that, It includes a base layer, a biomimetic self-healing layer, and an impermeable protective layer. The lower surface of the base layer is provided with an interlocking biomimetic tenon and mortise structure.

2. The biomimetic tongue-and-groove gradient self-healing composite waterproof membrane according to claim 1, characterized in that, The base layer has a long sheet structure, is made of modified high-density polyethylene, and has a thickness of 1.5 mm.

3. The biomimetic tongue-and-groove gradient self-healing composite waterproof membrane according to claim 1, characterized in that, The modified high-density polyethylene is obtained by extruding a mixture of high-density polyethylene resin, toughening agent and antioxidant in a mass ratio of 100:8:1, with a base layer thickness of 1.5 mm.

4. The biomimetic tongue-and-groove gradient self-healing composite waterproof membrane according to claim 1, characterized in that, The height of a single tenon in the biomimetic mortise and tenon structure is 5-8mm, and the distance between adjacent tenons is 10-15mm.

5. The biomimetic tongue-and-groove gradient self-healing composite waterproof membrane according to claim 1, characterized in that, The biomimetic self-healing layer is made by mixing epoxy resin, microcapsules, fluorosilane-modified nano-silica and curing agent in a mass ratio of 100:10:4:12 and applying the mixture by scraping, with a coating thickness of 0.8 mm.

6. The biomimetic tongue-and-groove gradient self-healing composite waterproof membrane according to claim 1, characterized in that, The impermeable protective layer is made by spraying a mixture of polyurethane modified epoxy resin and curing agent at a mass ratio of 100:15, with a coating thickness of 0.8 mm.

7. A method for repairing a biomimetic tongue-and-groove gradient self-healing composite waterproof membrane, used to repair the biomimetic tongue-and-groove gradient self-healing composite waterproof membrane according to any one of claims 1-6, characterized in that, Includes the following steps: A1. When the waterproof membrane is damaged, a three-dimensional ground-penetrating radar is used to scan the waterproof operation area. Through damage identification and positioning algorithms, the location, size, crack shape and leakage degree of the waterproof membrane damage are determined, and a complete three-dimensional distribution data model of the damaged area is generated. A2. Based on the three-dimensional distribution data model of the damaged area, grouting holes are arranged around the damaged point; A3. High-pressure intelligent grouting equipment is used to inject grout into the damaged area and surrounding soil through micro-hole grouting technology; A4. After grouting is completed, the area is left to stand for 24 hours to allow the grout to fully hydrate and solidify. The repair area is then scanned again using a three-dimensional ground-penetrating radar to check and verify the repair and soil reinforcement effects. Once the repair quality is confirmed to be up to standard, the repair is completed.

8. The repair method for a biomimetic tongue-and-groove gradient self-healing composite waterproof membrane according to claim 7, characterized in that, The positioning accuracy of the damage identification is within ±5cm.

9. The repair method for a biomimetic tongue-and-groove gradient self-healing composite waterproof membrane according to claim 7, characterized in that, The grouting holes are arranged 1.0-1.5m around the damaged point, with a spacing of 0.8-1.0m and a diameter of 50-60mm. The grouting holes penetrate the waterproof membrane and extend 0.5-1.0m into the soil layer below.

10. The repair method for a biomimetic tongue-and-groove gradient self-healing composite waterproof membrane according to claim 7, characterized in that, The grout is made from raw materials in the following mass ratio: modified polyurethane prepolymer: silicate cement: water: water-reducing agent = 40:60:25:0.5, which are mixed by stirring. The grouting process pressure is 0.3-0.5MPa and the grouting speed is 5-10L / min.

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