UHPC composite cable support used in severe cold environment with large temperature difference

Abstract

The invention relates to the technical field of cable supports, in particular to a UHPC composite cable support used in a severe cold large-temperature-difference environment, the strength of the UHPC composite cable support is enhanced through a three-layer composite structure of a mounting base and a supporting piece, the mounting efficiency is improved and the service life is prolonged through a connecting part and a connecting groove, a preparation formula of UHPC is improved, and the UHPC composite cable support is suitable for being used in the severe cold large-temperature-difference environment. The low-temperature resistance of the UHPC is enhanced, and the strength and the service life of the UHPC composite cable bracket in a severe cold large-temperature-difference environment can be ensured.

Description

Technical Field

[0001] This invention relates to the field of cable support technology, and specifically to a UHPC composite cable support for use in extremely cold environments with large temperature differences. Background Technology

[0002] Currently, cable trenches in power grid construction come in two forms: cast-in-place reinforced concrete cable trenches and prefabricated assembled cable trenches, each with its own characteristics and mature technology. Prefabricated assembled cable trenches, in particular, offer significant advantages and are widely used in power grid civil engineering construction. At present, prefabricated assembled cable trenches are still manufactured in factories according to design requirements, and are generally of the traditional "box-and-trough" type.

[0003] Cable supports are important components in cable trenches, used to support cables and prevent them from being corroded due to being too close to the ground. Currently, cable supports are generally made of angle steel, which requires processes such as pre-embedding iron plates, on-site welding, galvanizing for corrosion protection, installing continuous grounding flat steel, and blunting sharp corners. The installation process is complex. Cable supports made of angle steel are mostly of a split structure, with each component connected by bolts. Another type of cable support is made of concrete, and it is mostly of a one-piece structure.

[0004] The Barkol converter station project is an ultra-high-voltage direct current (UHVDC) project. The site is located in a high-wind corridor, with an average altitude of 1166.4–1182.8 meters. Historical meteorological data shows an average of 90 days of strong winds per year, with a maximum of 134 days; an average of 17.3 days of sandstorms per year, with a maximum of 54 days; extreme high temperatures of 45.1℃ and extreme low temperatures of -35.1℃. The large diurnal temperature range and extremely low temperatures make the cable supports highly susceptible to embrittlement, breakage, and other failures. Current angle steel and concrete cable supports used in frigid regions with large diurnal temperature variations present the following problems: Angle steel cable supports are prone to embrittlement in extremely cold environments with large temperature differences between day and night, leading to reduced strength and failure such as breakage. The limited space in cable trenches makes bolt installation cumbersome, inconvenient, and inefficient due to space constraints.

[0005] Concrete cable supports lack rigidity, toughness, and resistance to deformation in frigid environments with large temperature differences between day and night. The integrated structure increases construction difficulties under the limited space in the cable trench, and stress concentration is prone to occur at corners and connection points, making them more susceptible to failure problems such as breakage and fracture in frigid environments.

[0006] Angle steel cable supports and concrete cable supports lack protection in the humid and cold environment of cable trenches, making them prone to corrosion and low temperature problems, which reduces the service life of the cable supports.

[0007] Ultra-High Performance Concrete (UHPC) differs from traditional High Strength Concrete (HSC) and Steel Fiber Reinforced Concrete (SFRC) because it typically incorporates steel fibers or high-strength polymer fibers. It is not simply a high-strength version of traditional "High Performance Concrete (HPC)," but rather a new type of cement-based structural engineering material with clearly defined performance indicators. Currently, UHPC materials are mostly used in bridges and tunnels, with limited research in the power infrastructure sector. Its application in cable supports is even rarer, and there is a lack of UHPC materials suitable for cable supports in the harsh, humid, and corrosive environments of cable trenches. Summary of the Invention

[0008] To achieve the above objectives, the first aspect of the present invention provides the following technical solution: a UHPC composite cable bracket for use in extremely cold environments with large temperature differences, comprising a mounting base and a support member. The left end of the support member is horizontally fixedly mounted on the right side of the mounting base. Multiple connecting grooves are equidistantly arranged on the right side of the mounting base. The support member includes a connecting portion, a positioning flange, and a supporting portion. The connecting portion is located at the left end of the support member, wherein the connecting portion is interference-fitted with the connecting groove on the mounting base, and the connecting portion passes through the connecting groove, forming a mortise and tenon structure. Both the mounting base and the support member are three-layer composite structures. From the inside out, the structure consists of a skeleton, a UHPC layer, and a protective layer. The skeleton is made of polytetrafluoroethylene (PTFE). The skeleton is wrapped with a UHPC layer, which is low-temperature resistant and 20-30mm thick. The UHPC layer is then wrapped with a protective layer, which is a low-temperature resistant and corrosion-resistant layer, 3-5mm thick, made of polyurethane. The low-temperature resistant UHPC formula is: 980-1020 parts silicate cement; 200-215 parts mineral admixtures, composed of silica fume and fly ash in a mass ratio of 1:1.35. The mixture is composed of the following proportions: silica fume with a silica content ≥93%, specific surface area ≥19㎡ / g, and activity index ≥95%; fly ash with a silica content ≥65%, water requirement ratio <89, and particle size distribution of 1-5μm; aggregate: 1000-1100 parts, composed of quartz sand and quartz powder mixed at a mass ratio of 8.5:1.5, the quartz sand including one or more of the following particle sizes: 6-16 mesh, 30-50 mesh, and 80-90 mesh, and the quartz powder with a mesh size of 350 mesh; composite water-reducing agent: 70 -90 parts, composed of high-performance polycarboxylate superplasticizer and anionic superplasticizer containing carboxyl and sulfonic acid groups at a mass ratio of 1:1.5. The water reduction rate of the high-performance polycarboxylate superplasticizer is ≥40%, and the water reduction rate of the anionic superplasticizer containing carboxyl and sulfonic acid groups is ≥35%. The ratio of carboxyl and sulfonic acid groups in the anionic superplasticizer containing carboxyl and sulfonic acid groups is (6.5-7):(1.5-1.8); Copper-plated steel fiber: 325-330 parts, composed of steel fibers with a diameter of 0.18-0.22 mm and a length of 12-14 mm. Straight copper-plated steel fibers with a diameter of 0.11-0.13 mm and a length of 7-9 mm are mixed at a mass ratio of 1:2. The tensile strength of the parent material of the straight copper-plated steel fibers is ≥2000 MPa. Antifreeze aqueous solution: 10-15 parts, composed of triethanolamine 16-19 g / L, sodium pyruvate 12-13 g / L, and calcium chloride 25-32 g / L; air-entraining agent: 6-10 parts, composed of sodium dodecylbenzene sulfonate and sodium α-olefin sulfonate mixed at a mass ratio of 1:3; water: 100-160 parts.

[0009] The mounting base is vertically fixed on the inner side of the cable trench. The left side of the mounting base is detachably connected to the inner side of the cable trench. There are multiple support components, which are equidistantly installed on the mounting base in the vertical direction. The cross-section of the mounting base is I-shaped.

[0010] The positioning flange is located on the right side of the connecting part, and the left end of the positioning flange is connected to the right end of the connecting part. When the connecting part is inserted into the connecting groove, the left side of the positioning flange abuts against the right side of the mounting base. The support part is located on the right side of the positioning flange, and the left end of the support part is connected to the right end of the positioning flange.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: Compared to existing angle steel and concrete cable supports, this invention enhances the strength of the UHPC composite cable support through a three-layer composite structure of the mounting base and support components. This provides the structural strength prerequisite for using the "mortise and tenon" structure formed by the connecting part and the connecting groove in the cable support. Based on this, using the "mortise and tenon" structure formed by the connecting part and the connecting groove in the UHPC composite cable support, compared to the bolt connection structure of the existing technology, simplifies the installation structure and steps while ensuring connection strength, and improves installation efficiency. Compared to the integrated connection structure of the existing technology, it reduces construction difficulty, reduces stress concentration, and extends the service life of the cable support in harsh cold and large temperature difference environments.

[0012] Based on the application environment of extreme cold and large temperature differences, the preparation formula of UHPC was improved to enhance its low-temperature resistance. Through the coordination of various components and parameters in the preparation formula, UHPC exhibits excellent low-temperature resistance, ensuring its strength and service life in extreme cold and large temperature differences. By controlling the content and type of antifreeze aqueous solution, freezing damage to UHPC in extreme cold and large temperature differences is prevented, further enhancing its low-temperature resistance. Through the combination and ratio of components and content of composite water-reducing agent and air-entraining agent, the water-cement ratio of UHPC is reduced, making the UHPC structure denser while simultaneously forming a certain amount of uniformly distributed, stable, and closed microbubbles. This ensures both the internal density of the UHPC and the relief of expansion pressure, absorbing freeze-thaw energy, thus improving both freeze resistance and strength. By utilizing the properties of polytetrafluoroethylene (PTFE) such as high and low temperature resistance, corrosion resistance, high insulation, and high toughness, the strength and corrosion resistance of UHPC composite cable supports are improved in severe cold environments with large temperature differences, and the insulation effect of UHPC composite cable supports is also improved. By setting a low-temperature resistant and corrosion-resistant protective layer and the low thermal conductivity of polyurethane, which has good waterproof, corrosion-resistant, and heat insulation properties, the low-temperature resistance, corrosion resistance, and waterproof performance of UHPC composite cable supports are further improved. Attached Figure Description

[0013] Figure 1This is a three-dimensional structural schematic diagram of a UHPC composite cable support for use in extremely cold environments with large temperature differences, according to the present invention. Figure 2 This is a three-dimensional structural diagram of a mounting base for a UHPC composite cable bracket used in extremely cold environments with large temperature differences, according to the present invention. Figure 3 This is a right view of a mounting base for a UHPC composite cable bracket for use in extremely cold environments with large temperature differences, according to the present invention. Figure 4 This is a BB cross-sectional view of the mounting base of a UHPC composite cable bracket for use in extremely cold environments with large temperature differences, according to the present invention. Figure 5 This is a three-dimensional structural diagram of a support component for a UHPC composite cable bracket used in extremely cold environments with large temperature differences, according to the present invention. The correspondence between each mark and the part name is as follows: Mounting base 1, support 2, frame 3, UHPC layer 4, protective layer 5, connecting groove 1-1, connecting part 2-1, positioning flange 2-2, support part 2-3. Detailed Implementation

[0014] To make the technical means of realizing the invention, and to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0015] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0016] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0017] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0018] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0019] Example Reference Figure 1 As shown, this embodiment discloses a UHPC composite cable bracket for use in extremely cold environments with large temperature differences. It includes a mounting base 1 and support members 2. The mounting base 1 is vertically fixed to the inner side of the cable trench, and its left side is detachably connected to the inner side of the cable trench. The left end of the support member 2 is horizontally fixed to the right side of the mounting base 1. Multiple support members 2 are installed vertically at equal intervals on the mounting base 1. (Refer to...) Figure 2 As shown, the mounting base 1 has an I-shaped cross-section, and multiple connecting slots 1-1 are equidistantly arranged on the right side of the mounting base 1. (Refer to...) Figure 5 As shown, the support member 2 includes a connecting part 2-1, a positioning flange 2-2, and a support part 2-3. The connecting part 2-1 is located at the left end of the support member 2. The connecting part 2-1 is interference-fitted with the connecting groove 1-1 on the mounting base 1. The connecting part 2-1 passes through the connecting groove 1-1, and the two form a "mortise and tenon" structure to realize the installation and fixation of the support member 2 on the mounting base 1. The positioning flange 2-2 is located on the right side of the connecting part 2-1. The left end of the positioning flange 2-2 is connected to the right end of the connecting part 2-1. When the connecting part 2-1 passes through the connecting groove 1-1, the left side of the positioning flange 2-2 abuts against the right side of the mounting base 1 to further position the support member 2 and prevent the support member 2 from tilting. The support part 2-3 is located on the right side of the positioning flange 2-2. The left end of the support part 2-3 is connected to the right end of the positioning flange 2-2. The support part 2-3 is used to support cables of different sizes.

[0020] Reference Figure 3-4As shown, both the mounting base 1 and the support component 2 are three-layer composite structures. From the inside out, they are a skeleton 3, a UHPC layer 4, and a protective layer 5. The skeleton 3 is made of polytetrafluoroethylene (PTFE), which possesses properties such as high and low temperature resistance, corrosion resistance, high insulation, and high toughness. This improves the strength and corrosion resistance of the UHPC composite cable support in harsh environments with large temperature differences, and also enhances its insulation performance. The skeleton 3 is wrapped with an ultra-high performance concrete (UHPC) layer, specifically low-temperature resistant UHPC, with a layer thickness of 20-30mm. The UHPC layer is then wrapped with the protective layer 5, a low-temperature resistant and corrosion-resistant protective layer with a thickness of 3-5mm, made of polyurethane. Polyurethane has a low thermal conductivity and excellent waterproof, corrosion-resistant, and heat-insulating properties, improving the low-temperature resistance, corrosion resistance, and waterproof performance of the UHPC composite cable support. The low-temperature resistant UHPC formula is: silicate cement: 980-1020 parts. Mineral admixtures: 200-215 parts, composed of silica fume and fly ash mixed in a mass ratio of 1:1.35, with silica fume having a silica content ≥93%, a specific surface area ≥19㎡ / g, and an activity index ≥95%; fly ash having a silica content ≥65%, a water requirement ratio <89, and a particle size distribution of 1-5μm; Aggregate: 1000-1100 parts, composed of quartz sand and quartz powder in a mass ratio of 8. A 5:1.5 mixture is used, comprising one or more types of quartz sand with particle sizes of 6-16 mesh, 30-50 mesh, and 80-90 mesh, and quartz powder with a mesh size of 350 mesh; 70-90 parts of composite water-reducing agent are used, consisting of a high-performance polycarboxylate water-reducing agent and an anionic water-reducing agent containing carboxyl and sulfonic acid groups mixed in a mass ratio of 1:1.5. The high-performance polycarboxylate water-reducing agent has a water reduction rate ≥40%, and the anionic water-reducing agent containing carboxyl and sulfonic acid groups… The water reduction rate of the sub-type water-reducing agent is ≥35%. In anionic water-reducing agents containing carboxyl and sulfonic acid groups, the ratio of carboxyl groups to sulfonic acid groups is (6.5-7):(1.5-1.8). Copper-plated steel fiber: 325-330 parts, composed of straight copper-plated steel fibers with a diameter of 0.18-0.22 mm and a length of 12-14 mm, and straight copper-plated steel fibers with a diameter of 0.11-0.13 mm and a length of 7-9 mm, in a mass ratio... Mixed in a 1:2 ratio, the tensile strength of the straight copper-plated steel fiber base material is ≥2000MPa; antifreeze aqueous solution: 10-15 parts, composed of triethanolamine 16-19g / L, sodium pyruvate 12-13g / L, and calcium chloride 25-32g / L; air-entraining agent: 6-10 parts, composed of sodium dodecylbenzene sulfonate and sodium α-olefin sulfonate mixed in a mass ratio of 1:3; water: 100-160 parts.By combining the components and parameters in the above formula, the UHPC prepared using this formula possesses excellent low-temperature resistance, ensuring the strength and service life of UHPC in harsh environments with large temperature differences. By controlling the content and type of antifreeze aqueous solution, the UHPC is prevented from freezing and being damaged in harsh environments with large temperature differences, thus enhancing its low-temperature resistance. Through the combination and ratio of components and content of composite water-reducing agent and air-entraining agent, the water-cement ratio of UHPC is reduced, making the UHPC structure denser, while also enabling the formation of a certain amount of uniformly distributed, stable, and closed microbubbles. This ensures the internal density of the UHPC, alleviates expansion pressure, absorbs freeze-thaw energy, and maintains strength while improving freeze resistance.

[0021] 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 UHPC composite cable support for use in extremely cold environments with large temperature differences, characterized in that: The device includes a mounting base (1) and a support member (2). The left end of the support member (2) is horizontally fixed on the right side of the mounting base (1). Multiple connecting grooves (1-1) are equidistantly arranged on the right side of the mounting base (1). The support member (2) includes a connecting part (2-1), a positioning flange (2-2), and a support part (2-3). The connecting part (2-1) is located at the left end of the support member (2). The connecting part (2-1) is interference-fitted with the connecting groove (1-1) on the mounting base (1). The connecting part (2-1) passes through the connecting groove (1-1) and forms a "mortise and tenon" structure. Both the mounting base (1) and the support member (2) are three-layer composite structures, consisting of a skeleton (3), a UHPC layer (4), and a protective layer (5) from the inside out. The skeleton (3) is wrapped with the UHPC layer (4), and the UHPC layer (4) is wrapped with the protective layer (5).

2. The UHPC composite cable bracket for use in extremely cold environments with large temperature differences according to claim 1, characterized in that: The mounting base (1) is vertically fixedly installed on the inner side of the cable trench. The left side of the mounting base (1) is detachably connected to the inner side of the cable trench. There are multiple support members (2). The multiple support members (2) are installed on the mounting base (1) at equal intervals in the vertical direction. The cross-section of the mounting base (1) is I-shaped.

3. The UHPC composite cable bracket for use in extremely cold environments with large temperature differences according to claim 1, characterized in that: The positioning flange (2-2) is located on the right side of the connecting part (2-1). The left end of the positioning flange (2-2) is connected to the right end of the connecting part (2-1). When the connecting part (2-1) passes through the connecting groove (1-1), the left side of the positioning flange (2-2) abuts against the right side of the mounting base (1). The support part (2-3) is located on the right side of the positioning flange (2-2). The left end of the support part (2-3) is connected to the right end of the positioning flange (2-2).

4. A UHPC composite cable bracket for use in extremely cold environments with large temperature differences, as described in any one of claims 1-3, characterized in that: The skeleton (3) is made of polytetrafluoroethylene, the UHPC layer (4) is a low-temperature resistant UHPC layer, and the material is a low-temperature resistant UHPC material. The protective layer (5) is a low-temperature resistant and corrosion-resistant protective layer, and the material is polyurethane material.

5. A UHPC composite cable support for use in extremely cold environments with large temperature differences, as described in claim 4, characterized in that: The low-temperature resistant UHPC formula is as follows: silicate cement: 980-1020 parts; mineral admixture: 200-215 parts, which is a mixture of silica fume and fly ash in a mass ratio of 1:1.35, with silica fume having a silica content ≥93% and fly ash having a silica content ≥65%; aggregate: 1000-1100 parts, which is a mixture of quartz sand and quartz powder in a mass ratio of 8.5:1.

5. Composite water-reducing agent: 70-90 parts, composed of high-performance polycarboxylate water-reducing agent and anionic water-reducing agent containing carboxyl and sulfonic acid groups at a mass ratio of 1:1.

5. The water reduction rate of the high-performance polycarboxylate water-reducing agent is ≥40%, and the water reduction rate of the anionic water-reducing agent containing carboxyl and sulfonic acid groups is ≥35%. The ratio of carboxyl groups to sulfonic acid groups in the anionic water-reducing agent containing carboxyl and sulfonic acid groups is (6.5-7):(1.5-1.8); Copper-plated steel fiber: 325-330 parts The product consists of: 10-15 parts of an antifreeze aqueous solution, composed of 16-19 g / L triethanolamine, 12-13 g / L sodium pyruvate, and 25-32 g / L calcium chloride; and 6-10 parts of an air-entraining agent, composed of 6 parts sodium dodecylbenzenesulfonate and α-olefin sulfonate mixed in a 1:3 mass ratio. The parent material of the straight copper-plated steel fiber has a tensile strength ≥2000 MPa. Water: 100-160 parts.

6. A UHPC composite cable bracket for use in extremely cold environments with large temperature differences, as described in claim 5, is characterized in that: Quartz sand includes one or more of the following: 6-16 mesh, 30-50 mesh, and 80-90 mesh. Quartz powder has a mesh size of 350 mesh.

7. A UHPC composite cable bracket for use in extremely cold environments with large temperature differences, as described in claim 6, characterized in that: The specific surface area of ​​silica fume is ≥19㎡ / g and the activity index is ≥95%; the water requirement ratio of fly ash is <89 and the particle size distribution is 1-5μm.

8. A UHPC composite cable support for use in extremely cold environments with large temperature differences, as described in any of the preceding claims, characterized in that: The thickness of the UHPC layer (4) is 20-30 mm, and the thickness of the protective layer (5) is 3-5 mm.

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