A special-shaped compression-resistant cable protection pipe and a construction method thereof

Abstract

The application discloses a special-shaped compression-resistant cable protection pipe and a construction method thereof, and belongs to the technical field of cable protection pipes. The special-shaped compression-resistant cable protection pipe comprises a supporting pipe and an insulating protection pipe which is sleeved outside the supporting pipe, a protection cavity is formed between the supporting pipe and the insulating protection pipe, a plurality of top corner ribs which connect the supporting pipe and the insulating protection pipe are evenly arranged in the protection cavity, all the top corner ribs are rectangular strips which are distributed along the extension direction of the supporting pipe and the insulating protection pipe, a brittle support and a filler are arranged between any two adjacent top corner ribs, and the height of the brittle support is greater than the height of the top corner rib. The special-shaped compression-resistant cable protection pipe can solve the problem that the existing hexagonal honeycomb structure cable cannot meet the construction and service use requirements.

Description

Technical Field

[0001] This invention relates to the field of power engineering technology, specifically to a special-shaped pressure-resistant cable protection pipe and its construction method. Background Technology

[0002] As a key carrier for power transmission and distribution, buried power cables bear the core function of safely and efficiently transmitting electrical energy from the generation end to the user end. Their long-term reliability directly affects the stable operation of the power grid system. Therefore, in engineering practice, protective pipes are commonly used to externally protect buried cables to isolate them from multiple environmental threats such as soil static load, groundwater erosion, and external mechanical damage.

[0003] In existing protective tube technologies, the design concept of introducing a regular hexagonal honeycomb structure to achieve mechanical reinforcement has been applied: for example, the cable protective tubes described in References 1 and 2.

[0004] Reference 1: Chinese patent document with publication number CN220492617U.

[0005] Reference 1 describes a honeycomb-shell cable protection tube with a buffer function, including a protective tube, a honeycomb layer, and a beveled plate. The outer wall of the protective tube has a honeycomb layer at one end, and the end of the honeycomb layer away from the protective tube is connected to the inner wall of the outer shell. The outer wall of the outer shell has an anti-wear structure. The honeycomb layer has a beveled plate inside, and a water outlet is opened at one end of the honeycomb layer. A small opening is opened at the end of the honeycomb layer away from the water outlet. By setting the beveled plate and the water outlet, when rainwater enters the interior of the honeycomb layer through a break in the protective tube during rainy days, the rainwater slides on the beveled plate because one end is higher than the other end and flows to the outside through the water outlet of the honeycomb layer. This effectively prevents rainwater from soaking the protective tube inside the honeycomb layer and causing damage, thus improving its service life.

[0006] Reference 2: Chinese patent document with publication number CN222839395U.

[0007] Reference 2 describes a cable protection pipe with high pressure resistance, including a protective cover. The protective cover has an internal cable layering structure and self-assembly structures at both ends. The protective cover consists of a base and an arc-shaped protective plate positioned above the base and engaging with it. A pressure-resistant component, composed of pressure-resistant blocks and honeycomb blocks, is located between the arc-shaped protective plate and the base. When the protective cover is fixed to the ground, the base and the arc-shaped protective plate are integrated. When a vehicle drives over the arc-shaped protective plate, its arc shape provides significant pressure resistance. Simultaneously, the honeycomb blocks distribute the pressure across the entire arc-shaped protective plate. The pressure on the arc-shaped protective plate is then distributed to the base via the pressure-resistant blocks, and the base transmits the pressure to the ground. This prevents deformation and breakage of the arc-shaped protective plate, effectively protecting the cables inside the protective cover.

[0008] However, during construction, the frequent bending and dragging during cable laying places high demands on the flexibility of the materials. The high stiffness of hexagonal honeycomb cables clashes with this requirement, making bending and laying difficult and failing to meet bending requirements. In service, while existing hexagonal honeycomb cables can withstand some static soil loads after being buried underground, annular gaps generally exist between the conduit and the cable core. This prevents the cable core from being centered and the risk of eccentric stress from being eliminated, and also makes it impossible to actively adapt to deformation under uneven soil settlement. Furthermore, the fixed stiffness of the hexagonal honeycomb cable means it lacks elastic adaptability to thermal expansion and contraction caused by load fluctuations during operation, easily leading to stress accumulation and localized damage to the cable insulation layer over long-term service. Ultimately, this results in an inherent contradiction between construction flexibility and service structural strength in existing hexagonal honeycomb structures, making it difficult to simultaneously achieve both ease of construction and service reliability. Summary of the Invention

[0009] The purpose of this invention is to solve the problem that existing hexagonal honeycomb structure cables cannot meet both construction and service requirements, and to provide an irregularly shaped pressure-resistant cable protection pipe and its construction method.

[0010] To address the shortcomings of the aforementioned technical problems, the present invention adopts the following technical solution: an irregularly shaped pressure-resistant cable protection pipe, comprising a support pipe and an insulating protective pipe sleeved outside the support pipe, a protective cavity being formed between the support pipe and the insulating protective pipe, and a plurality of corner ribs connecting the support pipe and the insulating protective pipe being uniformly arranged in the protective cavity, all of which are rectangular strips distributed along the extension direction of the support pipe and the insulating protective pipe; A brittle support and filler are provided between each two adjacent corner ribs, and the height of the brittle support is greater than the height of the corner rib.

[0011] As a further optimization of the protection of irregularly shaped pressure-resistant cables of the present invention: the filler includes a first filler, which is made by mixing 15 to 30 parts of bisphenol F type liquid epoxy resin, 12 to 25 parts of hydroxyl-terminated polydimethyl silicone rubber and 2 to 4 parts of microcapsule-encapsulated dicyandiamide curing agent.

[0012] As a further optimization of the protection of irregularly shaped pressure-resistant cables of the present invention: the first filler contains 25 to 50 parts of inorganic filler, wherein the inorganic filler is 22 to 43 parts of talc powder and 3 to 7 parts of fumed nano silica.

[0013] As a further optimization of the protection of irregularly shaped pressure-resistant cables of the present invention: the first filler contains 0.5 to 1.5 parts of organic bentonite.

[0014] As a further optimization of the protection of the irregularly shaped pressure-resistant cable of the present invention: the filler includes a second filler and a third filler separated by a brittle support between two adjacent top corner ribs, and a fourth filler disposed inside the hollow of the brittle support. The second filler is 80-85 parts of hydroxyl polydimethyl polysiloxane, the third filler is 14-19 parts of methyl tributanone oxime silane crosslinking agent, and the fourth filler is 0.5-1.5 parts of a mixture of dibutyltin dilaurate and stannous octoate in a mass ratio of 2:1.

[0015] As a further optimization of the protection of irregularly shaped pressure-resistant cables of the present invention: the filler contains magnetic particles, which are iron powder or iron-silicon-aluminum soft magnetic powder coated with an insulating layer. The insulating coating layer is a double-layer dense reinforced coating structure, with a bottom layer of nano-silica insulation layer and a top layer of high-density epoxy resin passivation sealing layer.

[0016] As a further optimization of the present invention for the protection of irregularly shaped pressure-resistant cables: the brittle support is provided with stress concentration notches.

[0017] As a further optimization of the present invention for the protection of irregularly shaped pressure-resistant cables: the brittle support is made of granular glass blocks or ceramic materials sintered at low temperature.

[0018] As a further optimization of the irregular pressure-resistant cable protection of the present invention: the top corner ribs are provided with six, and the top corner ribs are made of hard rubber.

[0019] A construction method for an irregularly shaped, pressure-resistant cable protection conduit includes the following steps: S1. Insert the cable body into the support tube. The insulating protective tube is supported by multiple brittle supports and fillers, and is in a near-circular shape under the constraint of multiple top corner ribs, so as to carry out dragging, bending and laying operations. S2. After the main cable is laid in place, the trench is backfilled with soil. The lateral extrusion force of the backfill soil causes the brittle support to break, causing the insulation protection tube to squeeze the filler and form a polygonal shape under the restriction of the top corner rib. When the main cable is connected to the power grid and energized, the main cable generates Joule heat and power frequency magnetic field, which causes the filler to cross-link and solidify, and freezes the magnetic particles that are oriented under the influence of the power frequency magnetic field to form a three-dimensional mesh micro support skeleton. That is, after the filler and magnetic particles are solidified, they fill the protective cavity to work together with the top corner rib to solidify the polygonal shape of the insulation protection tube.

[0020] Compared with existing technologies, this invention has the following advantages: By setting up a brittle support structure in conjunction with corner ribs and filler, this invention supports and restricts the support tube and insulating protective tube located outside the core body, making the cable generally circular in shape during the laying and construction phase. Specifically, the corner ribs restrict the insulating protective tube to have multiple polygonal corners, and the central area of ​​the insulating protective tube between two adjacent corner ribs is lifted by the brittle support to form an arc-shaped convex state, thereby making the outer contour of the cable smoothly transition and significantly reducing frictional resistance and stress concentration during dragging and bending. At the same time, after the cable is laid in place and the soil is backfilled, the lateral extrusion force of the backfill soil causes the brittle support to fracture at the stress concentration gap according to the preset fracture strength threshold, triggering the filler to be uniformly mixed into the protective cavity formed between the support tube and the insulating protective tube. Combined with the Joule heat and power frequency magnetic field generated by the cable's energized operation, the filler is driven to cross-link and solidify, forming an auxiliary support skeleton, thus forming a good protective structure between the insulating protective tube and the support tube, thereby solving the problem that hexagonal honeycomb structure cables cannot meet both construction and service requirements. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the cross-sectional structure under construction conditions in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the cross-sectional structure in service state of Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the axial side view structure during the construction phase of Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the shaft side structure in service state according to Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the cross-sectional structure under construction conditions in Embodiment 2 of the present invention; Figure 6 This is a schematic diagram of the cross-sectional structure in service state of Embodiment 2 of the present invention; Figure 7 This is a schematic diagram of the axial side view structure during the construction phase of Embodiment 2 of the present invention; Figure 8 This is a schematic diagram of the shaft side structure in service state according to Embodiment 2 of the present invention; The markings in the diagram are: 1. Access channel; 2. Anti-slip layer; 3. Support tube; 4. Brittle support; 5. Filler; 501. Second filler; 502. Third filler; 503. Fourth filler; 504. Magnetic particles; 505. First filler; 506. Mixed filler; 6. Insulating protective tube; 7. Top corner rib; 8. Deformation cavity. Detailed Implementation

[0022] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0023] <Example 1> like Figure 1 and 3 As shown, an irregularly shaped pressure-resistant cable protection pipe includes a support pipe 3 and an insulating protective pipe 6 arranged sequentially from the inside to the outside. The support pipe 3 has an access channel 1 that can be inserted into the cable body, and a protective cavity is formed between the insulating protective pipe 6 and the support pipe 3. Multiple corner ribs 7 are evenly arranged in the protective cavity. The corner ribs 7 are rectangular strips arranged along the extension direction of the insulating protective pipe 6. Under the support of the support pipe 3, they restrict the connection between the insulating protective pipe 6 and the corner ribs 7, so that the insulating protective pipe 6 has a polygonal structure. The protective cavity is filled with filler 5 and multiple brittle supports 4. The multiple brittle supports 4 are evenly arranged between two adjacent corner ribs 7 in the protective cavity. The brittle supports 4 can separate the filler 5 between two adjacent corner ribs 7. The brittle supports 4 are hollow cuboids, and the hollow positions inside the brittle supports 4 form a deformation cavity 8. The height of the brittle support 4 is greater than the height of the top corner rib 7, so that the brittle support 4 can support the insulating protective tube 6 in the middle area between two adjacent top corner ribs 7. At the same time, in conjunction with the filler 5 squeezed by the brittle support 4, it supports the inner wall of the insulating protective tube 6, so that the surface of the insulating protective tube 6 between two adjacent top corner ribs 7 is arc-shaped and extends beyond the point where the top corner ribs 7 connect to the insulating protective tube 6. This ensures that the insulating protective tube 6 as a whole still has a roughly circular shape, thereby guaranteeing the overall flexibility of the insulating protective tube 6 and the effect of easy dragging, so as to facilitate the laying work of the cable body by the operators. Figure 2 and Figure 4 As shown, after the cable body and support pipe 3 are completed, when the soil is backfilled, the squeezing force of the soil will cause the brittle support 4 to break, which in turn will cause the deformation cavity 8 to break and be filled by the filler 5. Subsequently, with the restriction of the top corner rib 7, the insulating protective pipe 6 will use its own elastic deformation to squeeze the filler 5 to deform, so that the insulating protective pipe 6 as a whole takes on a corresponding polygonal structure.

[0024] The filler 5 includes a first filler 505 and magnetic particles 504. The first filler 505 and magnetic particles 504 are separated by a brittle support 4 located between two adjacent corner ribs 7. When the brittle support 4 breaks, such as Figure 6 and Figure 8 As shown, the insulating protective tube 6 utilizes its own elasticity to compress the filler 5, restoring it to a hexagonal shape. The first filler 505 is a temperature-curing resin material, specifically a compound system of 15-30 parts epoxy resin and 12-25 parts hydroxyl silicone rubber, with 25-50 parts inorganic filler added as a reinforcing component. This first filler 505 is a paste at room temperature, possessing good workability. When the cable body is energized and the temperature rises above 55°C, the epoxy resin and rubber components undergo a cross-linking reaction under the action of 2-4 parts of curing agent, gradually curing to form a semi-rigid structure.

[0025] The specific formulation of the first filler 505 is as follows: 27.8 parts of epoxy resin, the epoxy resin selected is CYDF-170 bisphenol F type liquid epoxy resin, which has low viscosity, self-leveling at room temperature, and is suitable for filling narrow cavities of cable ducts. The temperature resistance threshold is 55℃, which meets the core requirement of cross-linking triggered by power-on temperature rise. After curing, it has high strength support and compressive strength performance; 22.8 parts of hydroxyl silicone rubber, the selected is hydroxyl-terminated polydimethyl silicone rubber with a molecular weight of 20,000. It has excellent flexibility and can adapt to the dragging and bending deformation of the duct. It has excellent compatibility with epoxy resin. After compounding, it can offset the brittleness of pure epoxy curing, ensure the semi-rigid toughness of the system, and avoid cracking and peeling of the cured layer. The inorganic reinforcing filler comprises 44.3 parts, using a modified talc and fumed nano-silica compound system, with 30 parts or 22-43 parts of talc and 5 parts or 3-7 parts of fumed nano-silica. The talc enhances the rigidity and compressive strength of the matrix, while the fumed nano-silica refines the cross-linking network, significantly improving water-proofing, seepage prevention, and resistance to acid and alkali corrosion. The powder exhibits no agglomeration and does not affect the flow and pouring characteristics at room temperature. The latent curing agent comprises 3.8 parts, using microencapsulated dicyandiamide curing agent. It is completely inert at room temperature, with no risk of premature curing or gelation. At temperatures above 55°C, the capsule ruptures, triggering a cross-linking reaction to match the curing conditions of the cable body under power-on heating, thus ensuring that the curing trigger threshold of the first filler 505 is controllable. Furthermore, the first filler 505 can be mixed with 0.5 to 1.5 parts or 1.3 parts of a rheology modifier, which is organic bentonite, to adjust the paste viscosity of the first filler 505, preventing it from flowing, dripping, or leaving empty cavities after filling, thus ensuring the stability and uniformity of the construction and molding of irregularly shaped pipe cavities.

[0026] The magnetic particles 504 are specifically made of iron powder or iron-silicon-aluminum soft magnetic powder with insulating coating. Both iron powder and iron-silicon-aluminum soft magnetic powder have high magnetic permeability and electrical insulation properties. Under the influence of a power frequency magnetic field of more than 10 Gauss generated by the cable body being energized, they can overcome the viscous resistance of the resin and achieve directional arrangement. The insulating coating is to prevent the iron powder or iron-silicon-aluminum soft magnetic powder from generating eddy currents when energized, thereby avoiding affecting the operation of the cable body, and also to protect the iron powder from corrosion. In order to ensure the effectiveness of directional arrangement, the amount of magnetic particles 504 added is controlled at 15% to 25% of the total amount of the first filler 505, that is, 15% to 25% of the total amount of filler 5. The content range of magnetic particles 504 is set to ensure the sensitivity of magnetic field response, while avoiding excessive addition that would cause the resin system to become too viscous and affect the workability.

[0027] Iron-silicon-aluminum soft magnetic powder consists of 85% iron (Fe), 9.5% silicon (Si), and 5.5% aluminum (Al). The powder has a particle size of 200-300 mesh and a magnetic permeability ≥800 μH / m. It can rapidly and regularly align under a power frequency magnetic field of 10 Gauss or higher, exhibiting high magnetic response sensitivity and uniform magnetic field orientation. The insulating coating is a double-layer composite structure: a bottom layer of 0.3-1.0 μm thick nano-silica insulating layer and an outer layer of epoxy resin passivation layer. The coating is dense and pinhole-free, completely isolating conductive paths between particles, preventing eddy current generation, and simultaneously isolating it from water vapor, acidic or alkaline soil corrosive media, thus solving the problems of magnetic powder oxidation, corrosion, and pulverization failure. After the insulating coating is applied, the insulation resistance of the 504 magnetic particles is 10... 12 Above Ω, it does not affect the normal power transmission and insulation performance of the cable; after the first filler 505 is cross-linked and cured, it can lock the arrangement structure of the magnetic particles 504. After the magnetic field disappears, there is no structural collapse or disorder. After curing, the anisotropic support structure is stable and long-lasting.

[0028] The iron powder used is atomized high-purity iron powder with an iron content of over 99.2%, and a particle size of 200-300 mesh. It exhibits good workability and filling consistency, excellent magnetic response under weak magnetic fields, and can rapidly oriented and align in magnetic fields above 10 Gauss. The insulating coating layer uses a double-layer dense reinforced coating structure. The bottom layer is a 0.8-1.5μm thick nano-silica insulating layer to improve the insulation and rust prevention capabilities of the iron powder. The top layer is a high-density epoxy resin passivation and sealing layer to seal the micropores of the iron powder, suppress eddy current losses in alternating magnetic fields, and block moisture and corrosive ions. After coating the iron powder, the insulation resistance of the insulating coating layer is above 10 ohms. 12 Above Ω, the insulation performance meets the standard and does not interfere with the normal operation of the cable; after curing, the resin system firmly locks the iron powder orientation structure, with good arrangement stability, and meets the requirements of conventional compressive strength and magnetic field directional support; it is only suitable for low voltage, DC, and intermittent operation conditions, and is not applicable to medium and high voltage high frequency alternating magnetic field scenarios.

[0029] In filler 5, the epoxy resin and rubber system serves as the matrix phase, and magnetic particles 504 serve as the dispersed phase. Under the operating temperature of the cable body, a dual structural evolution is simultaneously completed. On one hand, the gradual cross-linking and curing of the epoxy resin freezes the directional arrangement of the magnetic particles 504 in situ, constructing a three-dimensional network micro-support skeleton oriented along the magnetic field direction within the protective cavity. On the other hand, the elastic buffer formed by the cross-linking of the resin matrix effectively absorbs external impact energy, while the dense cross-linked network structure blocks the penetration of acid and alkali ions and water molecules in the soil, achieving anti-corrosion function. When the on / off state of the cable body switches, causing the magnetic field to disappear, the directional arrangement of the magnetic particles 504 has been solidified and locked by the first filler 505, preventing structural collapse due to the disappearance of the magnetic field, thus ensuring the long-term stability of the support skeleton. This, in turn, solidifies the polygonal support structure of the insulating protective tube 6, ensuring the compressive and corrosion-resistant protection capabilities of the insulating protective tube 6 and the support tube 3 for the cable body under service conditions.

[0030] The support tube 3 is made of modified HDPE and high-toughness PVC-M material, which gives it a certain degree of support while also facilitating bending and dragging by workers during cable laying operations. Furthermore, the support tube 3 can conduct Joule heat generated during cable conduction to a certain extent, aiding in the curing of the filler 5. The insulating protective tube 6 is made of cross-linked polyethylene or ethylene propylene rubber to adapt to the environmental conditions under cable operation, while also possessing good resilience and flexibility to accommodate the deformation of the filler 5 and the brittle support 4 during support and breakage.

[0031] The brittle support 4 has a stress concentration notch in the middle, and is made of granular glass or low-temperature sintered ceramic material. Under the compressive stress of backfilling soil, it preferentially fractures at the stress concentration notch. The fragments of the brittle support 4 are dispersed in the first filler 505, further increasing the support effect of the solidified filler 5. Furthermore, the compressive strength of the brittle support 4 achieves a differentiated effect: maintaining structural integrity during the cable laying construction phase and fracturing under predetermined conditions during the backfilling phase. Specifically, the typical loads borne by the brittle support 4 during construction dragging and bending include the cable's self-weight (usually tens to hundreds of Newtons per meter), dragging friction of approximately several hundred Newtons, and bending stress generated by bending. Therefore, the fracture strength threshold of the brittle support 4 is set at a compressive strength of 3~8 MPa. The fracture strength threshold range set for the brittle support 4 ensures that it will not break unexpectedly during routine construction operations, while reliably triggering fracture even when the soil pressure exerted laterally on the cable's outer wall during backfilling is typically 10-50 kPa per meter of burial depth, and the stress acting on the support locally after structural amplification can reach several megapascals. Furthermore, the presence of stress concentration notches causes a stress concentration effect at the root of the notch under the preset load threshold, with a local stress concentration coefficient reaching 1.5-2.0. This significantly reduces the dispersion of the fracture trigger load and avoids premature or delayed fracture of some brittle supports 4 due to soil pressure fluctuations.

[0032] The inner wall of the support tube 3 is provided with an anti-slip layer 2, which is made of elastic flame-retardant material and has anti-slip protrusions on its inner wall. This ensures the connection stability between the cable body and the support tube 3 after the cable body is inserted into the support tube 3, thereby further guaranteeing the support and protection effect on the cable body.

[0033] Specifically, six corner ribs 7 are provided, giving the cable a hexagonal structure in service, thereby improving its compressive strength. Simultaneously, the skeleton formed by the filler 5 and the elastic buffer prevent the entry of corrosive substances, thus improving the overall corrosion resistance of the cable. The corner ribs 7 can be made of hard rubber material, or they can be made of hard rubber material with internal fiber ribs or metal wires.

[0034] During construction: The cable body, along with the support pipe 3, anti-slip layer 2, and the protective pipe consisting of the top corner rib 7 located outside the support pipe 3, which are installed through the access channel 1, are transported to the construction site. At this time, the brittle support 4 is in a complete state. The second filler 501 and the third filler 502 are separated by the brittle support 4. The deformation cavity 8 is retained in the protective cavity. The cable is roughly circular in shape and has good flexibility. Operators can drag, bend, and lay the cable according to the conventional cable laying process.

[0035] After the main cable is laid in place, the trench is backfilled with soil. The lateral compressive force of the backfill soil acts on the outer surface of the insulating protective tube 6 and is transmitted to the stress concentration notch in the middle of the brittle support 4, causing it to break first. After the brittle support 4 breaks, the deformation cavity 8 ruptures, allowing the filler 5 to redistribute within the protective cavity.

[0036] After the cable body is connected to the power grid and put into operation, the current transmitted by the cable body generates Joule heat. The support tube 3 absorbs the heat and buffers the temperature fluctuations, causing the temperature in the protective cavity area to gradually rise. At the same time, the power frequency magnetic field generated by the energized cable body acts on the soft magnetic powder in the first filler 505, causing it to oriented along the direction of the magnetic field. Under continuous heating or moisture absorption conditions, the resin system in the first filler 505 undergoes a progressive cross-linking reaction, freezing and solidifying the oriented structure of the magnetic particles 504 in situ within 7 to 15 days, forming a three-dimensional network micro-support skeleton.

[0037] After curing, the protective cavity transforms from the paste-like flexible filler 5 during the construction phase into a semi-rigid structure. Working in conjunction with the hexagonal apex ribs 7, it gives the insulating protective tube 6 a stable hexagonal shape, providing resistance to compression and soil settlement. At the same time, the dense cured resin matrix forms a water-proof and corrosion-resistant layer, which can still prevent corrosive media from contacting the cable body when the insulating protective tube 6 is accidentally damaged, thus achieving damage tolerance and protection functions.

[0038] <Example 2> This embodiment is basically the same as Embodiment 1, such as... Figure 5 and Figure 7 As shown, the filler 5 includes a second filler 501, a third filler 502, and a fourth filler 503. The second filler 501 and the third filler 502 are separated by a brittle support 4 located between two adjacent corner ribs 7. The fourth filler 503 is located within the deformation cavity 8 for separation. When the brittle support 4 breaks, as... Figure 6 and Figure 8 As shown, the second filler 501, the third filler 502 and the fourth filler 503 are mixed and contacted, and then solidified to form a mixed filler 506, so as to maintain the polygonal stable structure of the insulating protective tube 6, that is, to improve the overall corrosion resistance and compressive strength of the cable.

[0039] In Example 2, the second filler 501, the third filler 502, and the fourth filler 503 employ a two-component moisture-curing polysiloxane system. The second filler 501 comprises 80-85 parts, the third filler 502 comprises 14-19 parts, and the fourth filler 503 comprises 0.5-1.5 parts. The second filler 501 is a silanol condensation-cured polyorganosiloxane base polymer, the third filler 502 is a silane crosslinking agent containing hydrolyzable groups, and the fourth filler 503 is a condensation curing catalyst. The filler 5, including the second filler 501, the third filler 502, and the fourth filler 503, can absorb moisture and complete crosslinking under natural conditions without relying on cable temperature rise. The curing speed is positively correlated with temperature, and complete curing can be achieved in 7-15 days at room temperature.

[0040] Furthermore, the same magnetic particles 504 as in Example 1 can be mixed into both the second filler 501 and the third filler 502. In scenarios where the temperature of the cable body has not yet risen to the curing threshold of the polyurethane / epoxy system during the initial commissioning, the two-component polysiloxane system can still achieve structural shaping through moisture absorption and curing. At the same time, since the polysiloxane system is a two-component design, its crosslinking reaction mainly relies on chemical reaction rather than external energy input, making the curing process more controllable. After curing, it forms an organosilicon elastomer with both elasticity and toughness, which, in conjunction with the directional arrangement of magnetic particles 504, can also achieve the dual functions of compressive strength enhancement and corrosion protection sealing.

[0041] The second filler 501 consists of 82 parts, and is selected as hydroxyl polydimethyl polysiloxane with a viscosity of 5000 mPa·s and a temperature of 25°C. It serves as the core matrix phase of the system. The molecular chain ends of hydroxyl polydimethyl polysiloxane are enriched with highly active silanol groups (-Si-OH). The material selected for the second filler 501 has excellent moisture reactivity, is chemically stable when stored independently at room temperature, has no risk of self-curing or premature gelation, and has excellent storage stability.

[0042] The third filler 502 consists of 17 parts and is made of methyl tributanone oxime silane crosslinking agent. The third filler 502 is a special crosslinking component for room temperature moisture curing. Its molecules contain highly active hydrolyzable ethyl ketone oxime groups. When it comes into contact with water vapor in the air and soil environment, it can be rapidly hydrolyzed to generate silanol groups, which undergo a stable condensation reaction with the silanol groups of the second filler to quickly build a dense and stable organosilicon crosslinking network.

[0043] The fourth filler 503 is a powder, and it is made by compounding dibutyltin dilaurate and stannous octoate in a mass ratio of 2:1. The fourth filler 503 is stable in activity and has no risk of failure when stored alone at room temperature. After the rubber protective tube 6 is squeezed by external force and the soil settles, causing the brittle support 4 to break, the second filler 501, the third filler 502 and the fourth filler 503 are quickly mixed. The fourth filler 503 can significantly accelerate the crosslinking rate of the second filler 501 and the third filler 502, so that the second filler 501, the third filler 502 and the fourth filler 503 can be completely cured in 7 to 15 days in a room temperature and humid environment. The curing speed increases slightly with the increase of ambient temperature, and after curing, an organosilicon elastomer protective layer with high elasticity, high toughness and deformation resistance is formed.

[0044] The composition of the second filler 501, the third filler 502, the fourth filler 503, the first filler 505, and the magnetic particles 504 in this embodiment, the mechanism of their cross-linking and curing, and the composition ratio should all be understood as common knowledge to those skilled in the art, and will not be elaborated upon or illustrated here.

[0045] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A special-shaped, pressure-resistant cable protection pipe, characterized in that: It includes a support tube (3) and an insulating protective tube (6) sleeved outside the support tube (3). A protective cavity is formed between the support tube (3) and the insulating protective tube (6). Multiple corner ribs (7) connecting the support tube (3) and the insulating protective tube (6) are evenly arranged in the protective cavity. All corner ribs (7) are rectangular strips distributed along the extension direction of the support tube (3) and the insulating protective tube (6). A brittle support (4) and a filler (5) are provided between two adjacent top corner ribs (7), and the height of the brittle support (4) is greater than the height of the top corner rib (7).

2. The irregularly shaped pressure-resistant cable protection pipe as described in claim 1, characterized in that: The filler (5) includes a first filler (505), which is made by mixing 15 to 30 parts of bisphenol F type liquid epoxy resin, 12 to 25 parts of hydroxyl-terminated polydimethyl silicone rubber and 2 to 4 parts of microcapsule-encapsulated dicyandiamide curing agent.

3. The irregularly shaped pressure-resistant cable protection pipe as described in claim 2, characterized in that: The first filler (505) contains 25 to 50 parts of inorganic filler, which consists of 22 to 43 parts of talc powder and 3 to 7 parts of fumed nano silica.

4. The irregularly shaped pressure-resistant cable protection pipe as described in claim 2, characterized in that: The first filler (505) contains 0.5 to 1.5 parts of organic bentonite.

5. The irregularly shaped pressure-resistant cable protection pipe as described in claim 1, characterized in that: The filler (5) includes a second filler (501) and a third filler (502) separated by a brittle support (4) between two adjacent corner ribs (7) and a fourth filler (503) disposed inside the hollow interior of the brittle support (4). The second filler (501) is 80 to 85 parts of hydroxyl polydimethyl polysiloxane, the third filler (502) is 14 to 19 parts of methyl tributanone oxime silane crosslinking agent, and the fourth filler (503) is 0.5 to 1.5 parts of a mixture of dibutyltin dilaurate and stannous octoate in a mass ratio of 2:

1.

6. A special-shaped pressure-resistant cable protection pipe as described in claim 2 or 5, characterized in that: The filler (5) contains magnetic particles (504), which are iron powder or iron-silicon-aluminum soft magnetic powder coated with an insulating layer. The insulating coating is a double-layer dense reinforced coating structure, with a bottom layer of nano-silica insulating layer and a top layer of high-density epoxy resin passivation sealing layer.

7. The irregularly shaped pressure-resistant cable protection pipe as described in claim 1, characterized in that: The brittle support (4) is provided with stress concentration notches.

8. A special-shaped pressure-resistant cable protection pipe as described in claim 1 or 7, characterized in that: The brittle support (4) is made of particulate glass or ceramic material sintered at low temperature.

9. The irregularly shaped pressure-resistant cable protection pipe as described in claim 1, characterized in that: The top corner ribs (7) are provided in six parts, and the top corner ribs (7) are made of hard rubber.

10. The construction method of the irregularly shaped pressure-resistant cable protection pipe as described in claim 6, characterized in that: Includes the following steps: S1. Insert the cable body into the support tube (3). The insulating protective tube (6) is supported by multiple brittle supports (4) and filler (5), and is in a round shape under the restriction of multiple top corner ribs (7) for dragging, bending and laying operations. S2. After the main cable is laid in place, the trench soil is backfilled. The lateral extrusion force of the backfill soil causes the brittle support (4) to break, and the insulating protective tube (6) to squeeze the filler (5) and form a polygonal shape under the restriction of the top corner rib (7). When the main cable is connected to the power grid and powered on, the main cable generates Joule heat and power frequency magnetic field, so that the filler (5) is cross-linked and cured, and the magnetic particles (504) oriented by the power frequency magnetic field are frozen to form a three-dimensional mesh micro support skeleton. That is, after the filler (5) and magnetic particles (504) are cured, they fill the protective cavity to work with the top corner rib (7) to cure the polygonal shape of the insulating protective tube (6).

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