A double thermal insulation collaborative structure for a central water ditch of a tunnel in a cold region

Abstract

The utility model relates to water ditch heat preservation technical field, specifically disclose a kind of double heat preservation collaborative structure of cold region tunnel center water ditch, including passive heat preservation protection module, the inside of passive heat preservation protection module is provided with active heat preservation protection module, active heat preservation protection module still is provided with fastening assembly on it.This scheme is through the modularization design of passive heat preservation and active heat preservation, significantly improves the anti-freezing performance of tunnel drainage system, passive heat preservation module uses multilayer composite structure, including foam concrete layer, coal gangue ceramsite layer and mortar cushion, forms continuous heat preservation barrier, effectively blocks cold quantity transmission and disperses foundation frost heaving pressure, active heat preservation module is through the intelligent linkage of heat tracing cable and temperature sensing cable, real-time monitoring and adjusting drainage passage temperature, ensure that water flow does not freeze under extreme environment, double protection mechanism reduces long-term energy consumption, and avoids the problem that traditional single heat preservation mode is easy to fail.

Description

Technical Field

[0001] This utility model relates to the field of water ditch insulation technology, and specifically discloses a dual insulation synergistic structure for the central water ditch of a tunnel in a cold region. Background Technology

[0002] Currently, infrastructure construction, such as highways and railways, is increasingly extending to extremely cold regions such as high altitudes and high latitudes. In these areas, tunnel entrances are susceptible to the effects of cold air from outside, leading to frequent tunnel frost damage. Engineering practice shows that frost damage in cold-region tunnels often stems from improper drainage design or drainage system failure. In particular, when insulated side ditches and central drainage ditches freeze, the icing water overflows the drainage cross-section, causing road surface icing, which in turn threatens driving safety and shortens the tunnel's service life.

[0003] Currently, antifreeze measures for drainage ditches in cold-region tunnels are mainly divided into two categories: active insulation and passive insulation. Active insulation measures, such as electric heat tracing systems and hot water circulation systems, can effectively prevent freezing, but they need to operate continuously during the cold season, resulting in high energy consumption and expensive cumulative electricity costs. Passive insulation measures, such as covering the drainage ditch with an insulation layer, using phase change materials for temperature control, and deep burial of the drainage ditch, can reduce energy consumption, but the insulation materials are prone to aging or damage when buried underground for a long time, leading to a high risk of sudden failure and difficulty in real-time monitoring. In addition, there is no clear standard for the burial depth of the drainage ditch. Too deep a burial depth can cause construction safety problems and increase costs, while too shallow a burial depth cannot withstand extreme low temperatures. Existing single insulation measures cannot balance economy and reliability, and there is an urgent need for an efficient, energy-saving, and reliable solution. Utility Model Content

[0004] In view of this, the purpose of this utility model is to provide a dual-insulation synergistic structure for the central drainage ditch of a tunnel in cold regions, so as to solve the problem that a single insulation method cannot achieve the expected insulation effect. By adopting a combination of active and passive insulation, the insulation capacity of the drainage ditch is improved.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a dual-insulation synergistic structure for a central water ditch in a cold region tunnel, comprising a passive insulation protection module, an active insulation protection module being provided inside the passive insulation protection module, and fastening components being provided on the active insulation protection module; The passive thermal insulation protection module includes the tunnel body, the upper insulation unit, and the lower insulation unit; The active thermal insulation protection module includes several cable one and cable two; The fastening assembly includes a positioning frame.

[0006] Furthermore, an upper insulation unit and a lower insulation unit are respectively provided below the tunnel body. The upper insulation unit includes a foamed concrete layer and a coal gangue ceramsite layer. The lower insulation unit includes a foamed concrete layer and a mortar cushion layer. A foamed concrete layer is poured at the lower end of the tunnel body. A coal gangue ceramsite layer is built below the foamed concrete layer. A foamed concrete layer is built below the coal gangue ceramsite layer. A mortar cushion layer is poured at the lower end of the foamed concrete layer.

[0007] Furthermore, a waterproof sleeve is wrapped between the coal gangue ceramsite layer and the foamed concrete layer, and a heat insulation interlayer is wrapped inside the waterproof sleeve. A second waterproof sleeve is wrapped inside the heat insulation interlayer, and a drainage channel is wrapped inside the second waterproof sleeve.

[0008] Furthermore, the heat insulation interlayer includes a heat insulation base layer and a heat insulation outer layer. The heat insulation base layer is wrapped around the outer wall of the waterproof sleeve two. The heat insulation base layer is made of polyurethane insulation board material. The outer wall of the heat insulation outer layer is wrapped with the waterproof sleeve one. A gap is provided between the inner wall of the heat insulation outer layer and the outer wall of the heat insulation base layer. The gap can block heat transfer. The heat insulation outer layer is made of polyvinyl chloride board material. Several inner lining blocks are also distributed on the inner side of the heat insulation outer layer. The inner lining blocks and the heat insulation outer layer are an integral structure.

[0009] Furthermore, several of the aforementioned cables are distributed at the bottom of the drainage channel, with adjacent cables evenly spaced apart. Cable 1 is a heat tracing cable, and cable 2 is distributed in the middle of one side of the inner wall of the drainage channel. Cable 2 is a temperature sensing cable.

[0010] Furthermore, a positioning frame is provided on the surface of several of the cables and the surface of the cable. The positioning frame has a Z-shaped structure. The two ends of the positioning frame are respectively fitted to the inner wall of the drainage channel. Screws are also provided on the two ends of the positioning frame. The ends of the positioning frame are fixedly installed to the inner wall of the drainage channel by the screws. A threaded sleeve is provided through the middle of the positioning frame. A threaded rod is provided through the inside of the threaded sleeve and threadedly connected to it. A torsion knob is threadedly installed on the upper end of the threaded rod.

[0011] Furthermore, a bearing is provided at the end of the threaded rod away from the torsion knob. The inner ring wall of the bearing is interference-fitted with the end of the threaded rod. An arc-shaped block is fixedly installed at the lower end of the bearing. The side of the arc-shaped block away from the threaded rod is in close contact with the surface of the cable. Limiting blocks are fixedly installed on both sides of the arc-shaped block. Limiting grooves are opened on both sides of the inner wall of the positioning frame. The end of the limiting block away from the arc-shaped block is slidably in close contact with the inner wall of the limiting groove.

[0012] The working principle and beneficial effects of this solution are as follows: 1. This solution significantly improves the antifreeze performance of the tunnel drainage system through the modular design of passive and active insulation. The passive insulation module adopts a multi-layer composite structure, including a foamed concrete layer, a coal gangue ceramsite layer and a mortar cushion layer, forming a continuous insulation barrier, effectively blocking the transfer of cold energy and dispersing the frost heave pressure of the foundation. The active insulation module monitors and adjusts the temperature of the drainage channel in real time through the intelligent linkage of the heat tracing cable and the temperature sensing cable, ensuring that the water flow does not freeze in extreme environments. The dual protection mechanism reduces long-term energy consumption and avoids the problem of easy failure of traditional single insulation methods. 2. As described in 1, the high-density polyethylene waterproof sleeve, together with the polyurethane and polyvinyl chloride insulation layers, forms multiple layers of protection, which not only prevents external water vapor from penetrating, but also further blocks heat conduction through air gaps. The drainage channel made of foam glass itself has non-absorbent properties, and together with the multi-point support structure of the inner lining block, it maintains stability in freeze-thaw cycles. 3. As described in 2, the Z-shaped positioning frame, combined with the adjustable threaded clamping mechanism, can adapt to the installation requirements of different pipe diameters. The limiting groove and bearing structure ensure that the cable is not damaged during the crimping process. This design not only ensures the accuracy of cable laying during the construction phase, but also facilitates quick disassembly and replacement during later maintenance.

[0013] Other advantages, objectives, and features of this invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination and study, or may be learned from practice of this invention. The objectives and other advantages of this invention can be realized and obtained through the following description. Attached Figure Description

[0014] Figure 1 This is a schematic diagram showing the distribution of the various mechanisms in the embodiment; Figure 2 This is a schematic diagram of the overall collaborative structure of the drainage ditch insulation in an embodiment. Figure 3 Examples Figure 2 A schematic diagram of the front structure; Figure 4 This is a schematic diagram of the fastening assembly and cable structure in an embodiment. Figure 5 This is a schematic diagram of the thermal insulation sandwich structure in an embodiment; Figure 6 This is a schematic diagram of the cross-section of the thermal insulation outer layer in an embodiment.

[0015] The following are labeled in the attached diagram: 1. Passive thermal insulation module; 10. Tunnel body; 11. Foamed concrete layer one; 12. Coal gangue ceramsite layer; 13. Foamed concrete layer two; 14. Mortar cushion layer; 15. Waterproof sleeve one; 16. Thermal insulation interlayer; 17. Waterproof sleeve two; 18. Drainage channel; 1601. Thermal insulation base layer; 1602. Thermal insulation outer layer; 1603. Inner lining block; 2. Active thermal insulation and protection module; 20. Cable 1; 21. Cable 2; 3. Fastening assembly; 30. Positioning frame; 31. Screw; 32. Threaded sleeve; 33. Threaded rod; 34. Twist knob; 35. Bearing; 36. Arc block; 301. Limiting groove; 302. Limiting block. Detailed Implementation

[0016] The following detailed description illustrates the specific implementation method: Example like Figures 1 to 6 As shown, a dual-insulation collaborative structure for the central water ditch of a tunnel in a cold region is disclosed, including a passive insulation protection module 1, an active insulation protection module 2 is provided inside the passive insulation protection module 1, and a fastening component 3 is also provided on the active insulation protection module 2. The passive thermal insulation protection module 1 includes the tunnel body 10, the upper insulation unit, and the lower insulation unit; The active thermal insulation protection module 2 includes several cables 1 20 and 2 1. The fastening component 3 includes a positioning frame 30.

[0017] Below the tunnel body 10, there are upper and lower insulation units. The upper insulation unit includes a foamed concrete layer 11 and a coal gangue ceramsite layer 12. The lower insulation unit includes a foamed concrete layer 13 and a mortar cushion layer 14. The lower end of the tunnel body 10 is filled with foamed concrete layer 11. Below the foamed concrete layer 11, the coal gangue ceramsite layer 12 is built. Below the coal gangue ceramsite layer 12, the foamed concrete layer 13 is built. The lower end of the foamed concrete layer 13 is filled with mortar cushion layer 14. The foamed concrete layer 11 has a low density and a thermal conductivity of about 0.08-0.12 W / (m·K), which can reduce the downward transfer of heat. It is tightly bonded to the tunnel body 10 to avoid the cold bridge effect. It has moderate strength to support the drainage ditch structure and distribute the load. The coal gangue ceramsite layer 12 has an air layer formed by the pores inside the ceramsite. Its thermal conductivity is low, about 0. With a heat capacity of 1-0.15 W / (m·K), it significantly slows down the infiltration of cold air. Made from coal gangue, an industrial waste, it is low-cost and sustainable. Its porous structure can channel a small amount of seepage water, preventing water accumulation and frost heave. The first foamed concrete layer 11 provides basic insulation and support, while the coal gangue ceramsite layer 12 further blocks heat exchange, forming a double barrier of heat insulation. The second foamed concrete layer 13, together with the first foamed concrete layer 11 of the upper insulation unit, forms a continuous insulation layer, reducing the upward flow of cold air from the foundation. It has a certain degree of elasticity, which can alleviate the deformation pressure of soil frost heave on the drainage ditch. The mortar cushion layer 14, after the cement mortar hardens, provides a solid base, ensuring the accurate slope of the drainage ditch and preventing water accumulation. The dense structure blocks the upward seepage of groundwater, protecting the upper insulation unit. The second foamed concrete layer 13 makes up for the insulation needs of the lower layer, while the mortar cushion layer 14 enhances the structural stability and prevents foundation deformation from affecting the overall insulation performance.

[0018] A waterproof sleeve 15 is wrapped between the coal gangue ceramsite layer 12 and the foamed concrete layer 13. An insulation layer 16 is installed inside the waterproof sleeve 15, and a second waterproof sleeve 17 is installed inside the insulation layer 16. A drainage channel 18 is installed inside the second waterproof sleeve 17. Both the first and second waterproof sleeves 15 and 17 are made of high-density polyethylene, which is corrosion-resistant, anti-aging, and flexible, suitable for underground or humid environments. They are commonly used as outer sheaths for water supply and drainage pipes, effectively blocking moisture. The insulation layer 16 can be inserted between the first and second waterproof sleeves 15 for spaced insulation. While forming a double waterproof effect with the second waterproof sleeve 17, the first waterproof sleeve 15 can also provide waterproof protection for the heat insulation interlayer 16. The interior of the drainage channel 18 is a drainage ditch. The drainage channel 18 itself is made of foam glass board material. The foam glass is made by high-temperature foaming process and is filled with uniform closed pores. This structure makes it almost non-absorbent. The closed-cell structure blocks water penetration. Even if it is soaked or exposed to a humid environment for a long time, it can maintain stable physical properties. Because it does not absorb water, it is not easy to crack or deteriorate under repeated freeze-thaw cycles in cold regions. It is suitable for use in humid environments such as tunnels and underground projects.

[0019] The thermal insulation interlayer 16 comprises a thermal insulation base layer 1601 and a thermal insulation outer layer 1602. The thermal insulation base layer 1601 is wrapped around the outer wall of the waterproof sleeve 17. The thermal insulation base layer 1601 is made of polyurethane insulation board material. The outer layer 1602 is wrapped around the waterproof sleeve 15. A gap is provided between the inner wall of the thermal insulation outer layer 1602 and the outer wall of the thermal insulation base layer 1601, which can block heat transfer. The thermal insulation outer layer 1602 is made of polyvinyl chloride board material. Several inner lining blocks 1603 are also distributed on the inner side of the thermal insulation outer layer 1602. The inner lining blocks 1603 and the thermal insulation outer layer 1602 are an integral structure. When they are wrapped around the surface of the thermal insulation base layer 1601, they can form multi-point support, ensuring both gap insulation and the thermal insulation effect of the thermal insulation interlayer 16. The polyurethane insulation board used in the thermal insulation base layer 1601 has an extremely low thermal conductivity, approximately 0.022-0.028. With a thermal conductivity of W / (m·K), it effectively blocks heat transfer. It has low density but high strength, can withstand external loads of the drainage ditch, and avoids deformation. Its closed-cell structure has low water absorption, making it less prone to moisture damage and failure over long-term use. It is directly bonded to the outer wall of the waterproof sleeve 17 to form the first thermal insulation barrier. The PVC board used in the outer insulation layer 1602 has high hardness, protecting the inner polyurethane layer from construction damage or ground pressure. Its thermal conductivity is about 0.15-0.25 W / (m·K). The gap between it and the insulation base layer 1601 forms an air insulation layer, further blocking thermal bridges. It is resistant to acids and alkalis, resistant to underground environment corrosion, and has a long service life. The gap between it and the insulation base layer 1601 uses air as the insulation medium, reducing the efficiency of cold transfer.

[0020] Several cables 20 are distributed at the bottom of the drainage channel 18, with adjacent cables 20 being equidistantly spaced. Cable 20 is a heat tracing cable. Cable 21 is distributed in the middle of one side of the inner wall of the drainage channel 18, and is a temperature sensing cable. The heat tracing cables convert electrical energy into heat energy to directly heat the water flow or inner wall of the drainage channel 18 to prevent freezing. They are equidistantly arranged along the bottom of the drainage channel 18 to ensure that the heat is evenly covered across the entire drainage cross-section. When the temperature sensing cable detects that the temperature is lower than the set threshold, it sends a signal to the control center to trigger the heat tracing cable to start. The temperature is adjusted by external temperature control components. After the temperature rises back to a safe value, the temperature sensing cable sends a feedback signal, and the control center shuts down the heat tracing cable. The temperature sensing cable can sense the internal temperature change of the drainage channel 10 in real time and transmit the temperature data to the control center to trigger the start and stop of the heat tracing cable. It is arranged along the middle of the inner wall to avoid local interference from the bottom water flow or the top air and to reflect the overall temperature status.

[0021] Positioning frames 30 are provided on the surfaces of several cables 20 and cables 21. The positioning frames 30 have a U-shaped structure. The two ends of the positioning frames 30 are respectively attached to the inner wall of the drainage channel 18. Screws 31 are also provided on the surfaces of the two ends of the positioning frames 30. The ends of the positioning frames 30 are fixed to the inner wall of the drainage channel 18 by the screws 31. A threaded sleeve 32 is provided through the middle of the positioning frame 30. The connection between the threaded sleeve 32 and the positioning frame 30 is fixed by welding. A threaded rod 33 is provided through the threaded sleeve 32 and threadedly connected to it. A turning knob 34 is installed at the upper end of the threaded rod 33. The positioning frames 30 can be used to position individual cables at intervals, so that the cables can maintain a stable position in the drainage channel 18 for long-term use. If the diameter of the drainage channel 18 is large and the construction can be carried out in depth, multiple positioning frames 30 can be installed. If the diameter of the drainage channel 18 is small and the construction cannot be carried out in depth, the positioning frames 30 are installed along both ends of the drainage channel 18.

[0022] A bearing 35 is provided at the end of the threaded rod 33 away from the torsion knob 34. The inner ring wall of the bearing 35 is interference-fitted with the end of the threaded rod 33. An arc-shaped block 36 is fixedly installed at the lower end of the bearing 35. The side of the arc-shaped block 36 away from the threaded rod 33 is in close contact with the surface of the cable 20. Limiting blocks 302 are fixedly installed on both sides of the arc-shaped block 36. Limiting grooves 301 are respectively opened on both sides of the inner wall of the positioning frame 30. The end of the limiting block 302 away from the arc-shaped block 36 is connected to the limiting groove. The inner wall of 301 is designed to slide and fit tightly. When it is necessary to position and fasten the cable 20, the threaded rod 33 is rotated by turning the knob 34, so that the threaded rod 33 moves threadedly relative to the threaded sleeve 32. The limiting block 302 slides on the inner side of the limiting groove 301, so that the arc block 36 can move up and down. Thus, the arc block 36 is pressed tightly against the surface of the cable 20. The bearing 35 can rotate in cooperation with the threaded rod 33 to ensure the stable movement of the arc block 36.

[0023] In practice The passive thermal insulation module 1 of this scheme achieves long-term thermal insulation of the central drainage ditch in cold-region tunnels through a layered stacking design of foamed concrete layer 11, coal gangue ceramsite layer 12, foamed concrete layer 2 13, and mortar cushion layer 14. Foamed concrete layer 11 is directly poured below the tunnel body 10; its low thermal conductivity effectively blocks the downward transfer of cold energy from the tunnel structure and disperses the load on the drainage ditch. Coal gangue ceramsite layer 12 utilizes the air layer formed by the internal pores of the ceramsite to further delay the penetration of cold air; its industrial waste characteristics combine environmental friendliness and cost advantages. Foamed concrete layer 2 13 forms a continuous insulation layer with the upper foamed concrete layer 11, blocking... The cold air from the foundation is transmitted upwards, and the elastic properties can alleviate the pressure of frost heave deformation. The mortar cushion layer 14 provides a dense base, ensuring accurate drainage slope and blocking groundwater infiltration. The double-layer high-density polyethylene wrapping structure of waterproof sleeve 15 and waterproof sleeve 2 17, combined with the middle heat insulation interlayer 16, forms a composite barrier of waterproof-heat insulation-waterproof. The gap design between the polyurethane insulation board and the polyvinyl chloride board in the heat insulation interlayer 16 uses an air layer to enhance the thermal resistance effect. The multi-point support of the inner lining block 1603 further stabilizes the heat insulation structure. The foam glass board material of the drainage channel 18, due to its closed-cell characteristics, completely eliminates water absorption and avoids material deterioration caused by freeze-thaw cycles. The active heat preservation and protection module 2 achieves real-time temperature control within the drainage channel 18 through the linkage of the heating cable 20 (Cable 1) and the temperature sensing cable 21 (Cable 2). Cable 21, as a temperature sensing element, is arranged along the middle of the inner wall of the drainage channel 18 to monitor the ambient temperature and feed the data back to the control center. When the temperature is lower than the set threshold, the control center activates the heating cable 20. Its equidistant distribution at the bottom of the drainage channel 18 ensures that heat is evenly radiated to the water flow and the ditch wall, preventing local icing. The heating cable has high electrothermal conversion efficiency and can quickly raise the temperature inside the ditch to a safe range. Subsequently, the temperature sensing cable triggers a shutdown command, forming a stable control. The positioning frame 30 fixes the cable position through a Z-shaped structure. The screw 31 anchors the positioning frame 30 to the inner wall of the drainage channel 18. The threaded sleeve 32 and the threaded rod 33 cooperate to turn the knob 34, bearing 35 and arc block 36, which can adapt to the installation requirements of different cable thicknesses. The sliding constraint of the limiting block 302 and the limiting groove 301 ensures that the arc block 36 moves vertically and accurately presses the cable 20, avoiding displacement caused by construction vibration or water flow impact.

[0024] The above description is merely an embodiment of this utility model, and common knowledge such as specific structures and characteristics in the solution is not described in detail here. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of this utility model, and these should also be considered within the protection scope of this utility model. These modifications and improvements will not affect the effectiveness of the implementation of this utility model or its practicality.

Claims

1. A dual-insulation synergistic structure for a central water ditch in a cold-region tunnel, characterized in that: It includes a passive thermal insulation protection module, which has an active thermal insulation protection module inside it, and the active thermal insulation protection module is also provided with fastening components. The passive thermal insulation protection module includes the tunnel body, the upper insulation unit, and the lower insulation unit; The active thermal insulation protection module includes several cable one and cable two; The fastening assembly includes a positioning frame.

2. The dual-insulation synergistic structure for the central water ditch in a cold-region tunnel according to claim 1, characterized in that: The tunnel body is provided with an upper insulation unit and a lower insulation unit. The upper insulation unit includes a foamed concrete layer and a coal gangue ceramsite layer. The lower insulation unit includes a foamed concrete layer and a mortar cushion layer. The lower end of the tunnel body is filled with a foamed concrete layer. Below the foamed concrete layer is a coal gangue ceramsite layer. Below the coal gangue ceramsite layer is a foamed concrete layer. The lower end of the foamed concrete layer is filled with a mortar cushion layer.

3. The dual-insulation synergistic structure for the central water ditch in a cold-region tunnel according to claim 2, characterized in that: A waterproof sleeve is wrapped between the coal gangue ceramsite layer and the foamed concrete layer. A heat insulation interlayer is wrapped inside the waterproof sleeve, and a second waterproof sleeve is wrapped inside the heat insulation interlayer. A drainage channel is wrapped inside the second waterproof sleeve.

4. The dual-insulation synergistic structure for the central water ditch in a cold-region tunnel according to claim 3, characterized in that: The heat insulation interlayer includes a heat insulation base layer and a heat insulation outer layer. The heat insulation base layer is wrapped around the outer wall of the waterproof sleeve two. The heat insulation base layer is made of polyurethane insulation board material. The outer wall of the heat insulation outer layer is wrapped with the waterproof sleeve one. There is a gap between the inner wall of the heat insulation outer layer and the outer wall of the heat insulation base layer. The gap can block heat transfer. The heat insulation outer layer is made of polyvinyl chloride board material. Several inner lining blocks are also distributed on the inner side of the heat insulation outer layer. The inner lining blocks and the heat insulation outer layer are an integral structure.

5. The dual-insulation synergistic structure for the central water ditch in a cold-region tunnel according to claim 4, characterized in that: Several cables are distributed at the bottom of the drainage channel, with adjacent cables evenly spaced. Cable 1 is a heat tracing cable. Cable 2 is distributed in the middle of one side of the inner wall of the drainage channel. Cable 2 is a temperature sensing cable.

6. The dual-insulation synergistic structure for a central water ditch in a cold-region tunnel according to claim 5, characterized in that: A positioning frame is provided on the surface of several cables one and the surface of cables two. The positioning frame has a Z-shaped structure. The two ends of the positioning frame are respectively fitted to the inner wall of the drainage channel. Screws are also provided on the two ends of the positioning frame. The ends of the positioning frame are fixed to the inner wall of the drainage channel by the screws. A threaded sleeve is provided through the middle of the positioning frame. A threaded rod is provided through the inside of the threaded sleeve and threadedly connected to it. A torsion knob is threadedly installed on the upper end of the threaded rod.

7. The dual-insulation synergistic structure for a central water ditch in a cold-region tunnel according to claim 6, characterized in that: A bearing is provided at the end of the threaded rod away from the torsion knob. The inner ring wall of the bearing is interference-fitted with the end of the threaded rod. An arc-shaped block is fixedly installed at the lower end of the bearing. The side of the arc-shaped block away from the threaded rod is in close contact with the surface of the cable. Limiting blocks are fixedly installed on both sides of the arc-shaped block. Limiting grooves are opened on both sides of the inner wall of the positioning frame. The end of the limiting block away from the arc-shaped block is slidably in close contact with the inner wall of the limiting groove.

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