An assembled cable well dismantling-free formwork splicing node structure with a conductive sealing gasket and a waterproof method

Abstract

The present application relates to the technical field of power facilities and prefabricated building, especially to an assembled cable well formwork splicing node structure with conductive sealing washer and a waterproof method; by constructing a multi-cavity sealing washer, a flow guide groove, a water-swelling water stop strip and an outer sealing glue multi-stage composite waterproof system, the hollow rubber washer is rebounded to adapt to the soil settlement and the formwork micro-deformation, and the long-term solution to the underground well body leakage problem is realized; the sealing and equipotential grounding are integrated, the waterproof and conductive communication are completed synchronously through splicing and pressing, the traditional secondary cross-connection grounding flat steel and the welding fixing process are cancelled, the material consumption and the site construction period are greatly reduced, and the comprehensive construction cost is reduced. The matching staged tensioning standardized assembly process is used, the washer compression and the splicing pressure are controllable, and the construction quality is easy to control. The node is modularized and designed universally, is suitable for various prefabricated cable wells of round and rectangular shapes, and covers multiple scenes such as 10kV-110kV cable pipe and comprehensive pipe gallery branch well.

Description

Technical Field

[0001] This invention relates to the field of power facilities and prefabricated building technology, specifically to a prefabricated cable well splicing node structure with conductive sealing gaskets that does not require disassembly of templates and a waterproofing method. Background Technology

[0002] With the rapid development of urban underground pipe networks, prefabricated cable wells have been widely used due to their fast construction speed and minimal environmental impact. The no-formwork technology further eliminates the need for formwork removal, significantly improving construction efficiency. However, a long-standing technical contradiction exists at the splicing joints of prefabricated cable wells: the difficulty in simultaneously achieving both waterproofing and electrical continuity. On the one hand, underground cable wells have extremely high waterproofing requirements. Traditional splicing joints often use ordinary rubber sealing strips or sealant, but under the influence of groundwater pressure and uneven soil settlement, single sealing materials are prone to aging and failure, leading to leakage. On the other hand, modern cable wells require complete equipotential grounding and electromagnetic shielding. After traditional prefabricated components are assembled, the electrical connection at the joints is broken, necessitating secondary laying of grounding flat steel or copper braided tape for bridging. This not only increases construction procedures and material costs, but the bridging wires are also prone to corrosion and breakage in humid environments, leading to equipotential system failure and threatening cable operation safety. Currently, there is a lack of solutions on the market that can simultaneously achieve highly reliable waterproof sealing and low-impedance electrical continuity within a single joint structure. Summary of the Invention

[0003] The purpose of this invention is to provide a prefabricated cable well template splicing node structure with conductive sealing gasket and a waterproofing method to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A prefabricated cable well template splicing node structure with conductive sealing gaskets includes: a template body, wherein the splicing end face of the template body is provided with mutually matching stepped tongue and groove, wherein the stepped tongue and groove includes a first overlapping surface and a second overlapping surface. A pre-embedded conductive insert is embedded in the splicing end face of the template body, with its end exposed on the first overlapping surface; a composite conductive sealing gasket is disposed between the stepped tongue and groove of two adjacent template bodies. The composite conductive sealing gasket includes an elastic waterproof substrate and a conductive contact portion integrated within the elastic waterproof substrate. When two adjacent template bodies are assembled and pressed together, the elastic waterproof substrate deforms under pressure to fill the tongue and groove gap and achieve physical sealing. The conductive contact portion is tightly pressed against the pre-embedded conductive inserts on both sides to achieve electrical conduction between adjacent template bodies.

[0005] As a preferred embodiment of the present invention, the cross-section of the composite conductive sealing gasket has an asymmetric multi-chamber structure, specifically including: a main waterproof cavity, located in the middle of the gasket, which is a hollow closed-cell structure used to provide compression rebound force; The first conductive lip and the second conductive lip are located on both sides of the main waterproof cavity, and the conductive contact part is wrapped inside the first conductive lip and the second conductive lip. During assembly, the first conductive lip and the second conductive lip abut against the pre-embedded conductive inserts of the two adjacent template bodies.

[0006] As a preferred embodiment of the present invention, the conductive contact part is a flexible conductive core material, which is one of tin-plated copper braided strip, carbon fiber bundle, or aramid fiber rope wrapped with conductive silver paste; the elastic waterproof substrate is EPDM rubber or silicone rubber, and the surfaces of the first conductive lip and the second conductive lip are coated with a conductive carbon black coating.

[0007] As a preferred embodiment of the present invention, the pre-embedded conductive insert includes an anchoring end and a contact end. The anchoring end is embedded in the template body in a barbed or wavy shape. The contact end is a flat metal plate or metal mesh, and the surface elevation of the contact end is slightly higher than the surface of the first overlapping surface by 1cm-2cm.

[0008] As a preferred embodiment of the present invention, a flow guiding groove is provided on the second overlapping surface of the stepped tongue and groove, and the end of the flow guiding groove is connected to the drainage hole on the outside of the template body; a water-swellable sealing strip is also provided on the outside of the composite conductive sealing gasket, and the water-swellable sealing strip is located on the outside of the flow guiding groove.

[0009] A waterproofing method for prefabricated cable well splicing joints without disassembly, featuring conductive sealing gaskets, includes the following steps: S1. Clean the stepped tongue and groove joints of the splicing ends of two adjacent template bodies to ensure that the first and second overlapping surfaces are free of debris and standing water; S2. Insert the composite conductive sealing gasket into the stepped tongue and groove of one of the template bodies, so that the conductive contact part of the gasket is aligned with the pre-embedded conductive insert. S3. Align and fit the stepped tongue and groove of the other template body with the washer, and perform initial positioning using external assembly fixtures or temporary supports. S4. By using tie bolts or external annular tensioning belts that penetrate the template body, apply axial assembly prestress to two adjacent template bodies, so that the main waterproof cavity compression rate of the composite conductive sealing gasket reaches 30%-50%, and at the same time, make the conductive contact part and the pre-embedded conductive insert form an interference fit. S5. Inject polyurethane sealant or epoxy conductive adhesive into the outermost joint of the stepped tongue and groove joint to form an external sealing layer. S6. Use a micro resistance tester to measure the contact resistance between adjacent template bodies to confirm that the electrical conduction is qualified; and after the outer sealing layer is cured, conduct a water spray or water pressure test to confirm that the waterproofing is qualified.

[0010] As a preferred embodiment of the present invention, in step S4, the application of the axial assembly prestress adopts a graded tensioning method: first, 30% of the design prestress is applied for position fine adjustment, then 60% is applied to check the compression state of the washer, and finally 100% is applied and locked.

[0011] As a preferred embodiment of the present invention, in step S5, if the injected material is epoxy resin conductive adhesive, the conductive adhesive contains silver-coated copper powder or graphene microflakes, and after curing, the outer sealing layer serves as an auxiliary conductive channel connected in parallel with the composite conductive sealing gasket.

[0012] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention utilizes a multi-stage composite waterproofing system consisting of a multi-cavity sealing gasket, a guide channel, a water-swellable sealing strip, and an outer sealant. The hollow rubber gasket's rebound adapts to soil settlement and formwork micro-deformation, effectively solving the problem of underground well leakage. The sealing and equipotential grounding are integrated, with waterproofing and conductive connection completed simultaneously during assembly and compression. This eliminates the traditional secondary grounding flat steel and welding fixing processes, significantly reducing material consumption and on-site construction time, and lowering overall construction costs. A standardized assembly process with graded tensioning ensures controllable gasket compression and assembly pressure. Upon completion, acceptance can be quantified through resistance and water pressure tests, facilitating easy quality control. The modular, universal design of the nodes adapts to various prefabricated cable wells, including round and rectangular shapes, covering multiple scenarios such as 10kV~110kV cable ducts and integrated utility tunnel branch wells.

[0013] 2. In this invention, by using micro-convex pre-embedded conductive inserts and conductive lips with interference compression, combined with conductive coating and outer conductive adhesive to form multiple parallel conductive channels, the node contact resistance is stably lower than 0.005Ω, which fully meets the requirements of electromagnetic shielding and fault discharge, and avoids the power safety hazards caused by the corrosion and breakage of traditional exposed grounding parts; the entire set of components is made of water-resistant, acid and alkali-resistant, and anti-aging base materials, with no exposed easily corroded metal connectors, and can be used for a long time in complex environments with high water levels and corrosive soil, with a long service life. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall cross-sectional structure of the prefabricated cable well splicing body node without disassembly according to the present invention; Figure 2 This is a schematic diagram of an enlarged cross-section of a water-swellable sealing strip; Figure 3 A schematic diagram of the cross-sectional installation of the pre-embedded conductive insert; Figure 4 This is a schematic cross-sectional view of a composite conductive sealing gasket.

[0015] In the figure: 1. First overlapping surface; 2. Second overlapping surface; 3. Water-swellable sealing strip; 4. Embedded conductive insert; 5. Composite conductive sealing gasket; 6. First conductive lip; 7. Main waterproof cavity; 8. Second conductive lip. Detailed Implementation

[0016] 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. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0017] Example 1, please refer to Figures 1-4 The present invention provides a technical solution: This splicing joint structure mainly consists of a template body, a pre-embedded conductive insert 4, and a composite conductive sealing gasket 5. The template body is made of glass fiber reinforced polyurethane pultrusion molding, which is lightweight and high-strength. The splicing end face of the template body is processed into a stepped tongue and groove joint, including a first overlapping surface 1 and a second overlapping surface 2. A pre-embedded conductive insert 4 is pre-embedded on the first overlapping surface 1. The insert is made of copper, and its anchoring end is wavy to ensure the bonding force with the template body. The contact end surface is slightly higher than the overlapping surface by 1mm to ensure a tight press-fit.

[0018] Core component composite conductive sealing gasket 5 (e.g.) Figure 4 (As shown) It is formed using a co-extrusion process. Its main waterproof cavity 7 is an elliptical hollow structure, made of ethylene propylene diene monomer (EPDM) rubber with a Shore hardness of 50A, providing excellent resilience. The first conductive lip 6 and the second conductive lip 8 are internally wrapped with tin-plated copper braided strips, and the lip surfaces are coated with a conductive carbon black coating to reduce surface contact resistance. A water-swellable sealing strip 3 is bonded to the outermost side of the gasket.

[0019] Example 2: In a 110kV urban underground cable duct project, this system was used for the assembly of prefabricated cable wells. The specific steps are as follows: S1. End face pretreatment: Use a high-pressure air gun to clean the stepped tongue and groove to ensure there is no mud, sand, or water accumulation. S2. Washer positioning: Insert the composite conductive sealing washer 5 into the tongue and groove of the lower template body, ensuring that the conductive lip accurately covers the pre-embedded conductive insert 4. S3. Assembly and initial pressure: Hoist the upper template body, align its tongue and groove with the washer, and use guide pins for initial positioning. S4. Applying prestress: Insert tie bolts and use a torque wrench for graded tensioning. In the first stage, apply 30% torque to adjust the template flatness; in the second stage, apply 60% torque, observing that the main waterproof cavity 7 is compressed by about 30% and the conductive lip is flattened; in the third stage, apply 100% design torque and tighten the nuts. At this time, the tin-plated copper braided strip and the copper insert undergo plastic micro-deformation, forming a large area of ​​metal-metal contact. S5. Secondary Sealing: At the outermost joint of the tongue and groove joint, inject epoxy resin conductive adhesive mixed with graphene microflakes using a glue gun, and smooth the surface. S6. Testing: Use a milliohm meter to measure the resistance between the pre-embedded grounding terminals of the upper and lower templates. The measured contact resistance is 0.005Ω, indicating electrical continuity is qualified. An external water spray test is then conducted; no leakage is observed, indicating waterproofing is qualified.

[0020] The workflow of this invention is as follows: Using the prefabricated cable well template splicing node structure and waterproofing method with conductive sealing gaskets designed in this solution, during operation, the stepped tongue and groove joints of the splicing ends of two adjacent template bodies are cleaned to ensure that the first overlapping surface 1 and the second overlapping surface 2 are free of debris and standing water; the composite conductive sealing gasket 5 is inserted into the stepped tongue and groove joint of one of the template bodies, aligning the conductive contact part of the gasket with the pre-embedded conductive insert 4; the stepped tongue and groove joint of the other template body is aligned and fitted with the gasket, and initial positioning is achieved using external assembly clamps or temporary supports; through… The tie bolts or external annular tensioning strips that penetrate the template body apply axial prestress to two adjacent template bodies, so that the main waterproof cavity 7 of the composite conductive sealing gasket 5 has a compression rate of 30%-50%, and at the same time, the conductive contact part and the pre-embedded conductive insert 4 are press-fitted together. Polyurethane sealant or epoxy resin conductive adhesive is injected into the outermost joint of the stepped tongue and groove to form an external sealing layer. The contact resistance between adjacent template bodies is measured using a micro resistance tester to confirm that the electrical conductivity is qualified. After the external sealing layer is cured, a water spray or water pressure test is performed to confirm that the waterproofing is qualified.

[0021] All standard parts used in this application can be purchased from the market. The specific connection methods of each part adopt conventional methods such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts and equipment adopt conventional models in the prior art and are also general components, which are common knowledge in this field.

[0022] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A prefabricated cable well formwork splicing node structure with conductive sealing gaskets, characterized in that: include: The template body has matching stepped tongue and groove joints on its splicing end face, the stepped tongue and groove joints including a first overlapping surface (1) and a second overlapping surface (2). A pre-embedded conductive insert (3) is embedded in the splicing end face of the template body, and its end is exposed on the first overlapping surface (1); a composite conductive sealing gasket (5) is set between the stepped tongue and groove of two adjacent template bodies. The composite conductive sealing gasket (5) includes an elastic waterproof substrate and a conductive contact part integrated in the elastic waterproof substrate. When two adjacent template bodies are assembled and pressed together, the elastic waterproof substrate is deformed under pressure to fill the tongue and groove gap and achieve physical sealing. The conductive contact part is tightly pressed with the pre-embedded conductive inserts (4) on both sides to achieve electrical conduction between adjacent template bodies.

2. The prefabricated cable well template splicing node structure with conductive sealing gasket as described in claim 1, characterized in that, The cross-section of the composite conductive sealing gasket (5) is an asymmetric multi-chamber structure, specifically including: a main waterproof cavity (7), located in the middle of the gasket, which is a hollow closed-cell structure used to provide compression rebound force; The first conductive lip (6) and the second conductive lip (8) are located on both sides of the main waterproof cavity (7), and the conductive contact part is wrapped inside the first conductive lip (6) and the second conductive lip (8). During assembly, the first conductive lip (6) and the second conductive lip (8) abut against the pre-embedded conductive inserts (4) of the two adjacent template bodies.

3. The prefabricated cable well template splicing node structure with conductive sealing gasket as described in claim 1, characterized in that, The conductive contact part is a flexible conductive core material, which is one of tin-plated copper braided strip, carbon fiber bundle or aramid fiber rope wrapped with conductive silver paste; the elastic waterproof substrate is ethylene propylene diene monomer (EPDM) rubber or silicone rubber, and the surfaces of the first conductive lip (6) and the second conductive lip (8) are coated with a conductive carbon black coating.

4. The prefabricated cable well template splicing node structure with conductive sealing gasket as described in claim 1, characterized in that, The pre-embedded conductive insert (4) includes an anchoring end and a contact end. The anchoring end is embedded in the template body in the form of barbs or waves. The contact end is a flat metal plate or metal mesh, and the surface elevation of the contact end is slightly higher than the surface of the first overlapping surface (1) by 1cm-2cm.

5. The prefabricated cable well template splicing node structure with conductive sealing gasket according to claim 1, characterized in that, The second overlapping surface (2) of the stepped tongue and groove is provided with a flow guide groove, the end of which is connected to the drainage hole on the outside of the template body; the outer side of the composite conductive sealing gasket (5) is also provided with a water-swellable sealing strip (3), which is located on the outside of the flow guide groove.

6. A waterproofing method for prefabricated cable well splicing nodes with conductive sealing gaskets that do not require disassembly of templates, characterized in that, Includes the following steps: S1. Clean the stepped tongue and groove joints of the two adjacent template bodies to ensure that the first overlapping surface (1) and the second overlapping surface (2) are free of debris and standing water. S2. Insert the composite conductive sealing gasket (5) into the stepped tongue and groove of one of the template bodies, so that the conductive contact part of the gasket is aligned with the pre-embedded conductive insert (4). S3. Align and fit the stepped tongue and groove of the other template body with the washer, and perform initial positioning using external assembly fixtures or temporary supports. S4. By using tie bolts or external annular tensioning belts that penetrate the template body, apply axial assembly prestress to two adjacent template bodies, so that the main waterproof cavity (7) of the composite conductive sealing gasket (5) has a compression rate of 30%-50%, and at the same time, make the conductive contact part and the pre-embedded conductive insert (4) produce an interference fit. S5. Inject polyurethane sealant or epoxy conductive adhesive into the outermost joint of the stepped tongue and groove joint to form an external sealing layer. S6. Use a micro resistance tester to measure the contact resistance between adjacent template bodies to confirm that the electrical conduction is qualified; and after the outer sealing layer is cured, conduct a water spray or water pressure test to confirm that the waterproofing is qualified.

7. The construction process for preventing mortar segregation and uniform pouring in the inner cavity of the template for a groundless conductive cable well according to claim 6, is characterized in that, In step S4, the axial assembly prestress is applied using a graded tensioning method: first, 30% of the design prestress is applied for position fine-tuning, then 60% is applied to check the compression state of the washers, and finally 100% is applied and locked.

8. A waterproofing method for prefabricated cable well splicing nodes with conductive sealing gaskets that do not require disassembly, as described in claim 6, is characterized in that... In step S5, if the injected material is epoxy resin conductive adhesive, the conductive adhesive contains silver-coated copper powder or graphene micro-flakes. After curing, the outer sealing layer serves as an auxiliary conductive channel connected in parallel with the composite conductive sealing gasket (5).

Images