A hollow fiber optic sensing hybrid cable for tunnel monitoring

Abstract

This invention relates to the field of hybrid optical fiber cables, and in particular to a hollow-core optical fiber sensing hybrid cable for tunnel monitoring. Addressing the problems of existing technologies, this invention provides a hollow-core optical fiber sensing hybrid cable for tunnel monitoring. Multiple hollow optical fibers and multi-core optical fibers are evenly distributed in a ring, with a reinforcing core at the center. Cable grease fills the spaces between the multi-core optical fibers, hollow optical fibers, and the reinforcing core. A multi-layered spiral protective tape is wound around the outer layer, with a protective sleeve on the outer layer of the protective tape. A protective tube is placed on the outer side of the protective sleeve, and a protective spring is fitted between the protective tube and the protective sleeve. Multiple reinforcement components are installed on the surface of the protective sleeve. This application employs a hybrid structure combining hollow optical fibers and multi-core optical fibers, which can stably transmit multi-channel tunnel monitoring data, effectively avoiding signal congestion and delay, improving the reliability of the sensing system. With the help of the reinforcement components, it can accurately adapt to the bending radius of different tunnel sections without the need for additional auxiliary supports.

Description

Technical Field

[0001] This invention relates to the field of fiber optic hybrid cables, and in particular to a hollow fiber optic sensing hybrid cable for tunnel monitoring. Background Technology

[0002] During the construction and operation phases of tunnel engineering, monitoring the stability of the tunnel structure is crucial. It is necessary to capture potential risks such as surrounding rock deformation, segment displacement, and water leakage in real time. The sensor transmission system, as the core of this monitoring, directly determines the accuracy and reliability of the monitoring data. Currently, the commonly used sensor transmission medium in tunnel monitoring is traditional solid optical fiber cable. Because the optical signal is transmitted within the glass core of traditional solid optical fiber, material absorption loss and nonlinear effects are significant, making it difficult to overcome the nonlinear Shannon limit, resulting in limited transmission bandwidth. When multiple channels of monitoring data need to be transmitted simultaneously, signal congestion and delays are prone to occur, failing to meet the needs of large-scale, high-precision tunnel monitoring. Furthermore, solid optical fiber has weak resistance to external interference; vibrations during tunnel construction and surrounding rock compression during operation can easily cause fiber deformation, further exacerbating transmission loss and even causing signal interruptions.

[0003] Patent application CN201610365463.7 discloses a hybrid optoelectronic cable capable of simultaneously achieving high-speed and secure transmission of both power and information; it is easy to lay; has low material and labor costs; and a long service life. Another example is patent application CN201610631866.1, which discloses a hybrid optoelectronic transmission heat-balanced cable with a hollow internal structure and a flowing heat-conducting medium injected into the center; the electrical transmission unit and the heat-balanced unit are arranged in two or more groups, spaced apart and closely surrounding the optical transmission unit. This invention continuously and stably transfers internal heat outwards from the cable, ensuring the stability of optoelectronic transmission and the safety performance of the cable.

[0004] However, the existing fiber optic hybrid cable structure is difficult to adapt to the complex curved inner walls and harsh working conditions of tunnels. Most fiber optic cables use rigid outer sheaths, which cannot be flexibly adjusted according to the tunnel cross-sectional profile. During installation, a large number of auxiliary supports are required for fixation, making the process cumbersome and with poor adaptability. At the same time, moisture and dust present in the tunnel environment can easily penetrate into the cable body. The existing sealed structure of the cable body is difficult to resist corrosion in the long term, leading to moisture aging of the optical fibers, shortening their service life, and making the cable body prone to breakage due to stress concentration in the deformable section of the tunnel, affecting the continuous operation of the monitoring system. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a hollow-core fiber optic sensing hybrid cable for tunnel monitoring, effectively solving the problems mentioned in the background section.

[0006] The technical solution adopted by the present invention to solve the above problems is as follows:

[0007] A hollow-core fiber optic sensing hybrid cable for tunnel monitoring includes hollow optical fibers and solid optical fibers. Multiple solid optical fibers are aggregated together, and an outer sheath is provided. The sheath is filled with fiber grease to form a multi-core optical fiber. The multiple hollow optical fibers and multi-core optical fibers are evenly distributed in a ring, with a reinforcing core at the center. Cable grease is filled between the multi-core optical fibers, hollow optical fibers, and reinforcing core. The outer layer is wrapped with a multi-layer spirally distributed protective tape to tightly wrap the optical fibers. A protective sleeve is provided on the outer layer of the protective tape, and a protective tube is provided on the outer side of the protective sleeve. A protective spring is sleeved between the protective tube and the protective sleeve. Multiple reinforcement components are installed on the surface of the protective sleeve.

[0008] The reinforcement includes multiple connecting clamps fitted onto the surface of the protective tube, hinge units connected to the upper and lower sides of the connecting clamps, and a retractable adjustment frame; two adjacent hinge units are hinged to each other, and the outermost hinge unit is connected to the adjustment frame. When the adjustment frame retracts inward, it can drive the hinged units to retract inward into an arc shape, which, under the linkage of the connecting clamps, causes the protective tube to bend into an arc shape; the length of a single hinge unit is adjustable.

[0009] Furthermore, the hinge unit includes a first connecting block and a second connecting block. The first connecting block and the second connecting block in adjacent hinge units are hinged to each other. Connecting posts are respectively provided on the upper and lower sides of the inner ends of the first connecting block and the second connecting block in the same hinge unit. Baffles are respectively fixedly connected to both ends of the connecting posts. The interior of the first connecting block and the second connecting block are respectively provided with mounting grooves that can slide with the baffles. The inner end of the mounting groove is respectively provided with an opening that can slide with the connecting post. The baffle is slidably connected in the mounting groove. Engaging tooth grooves are respectively provided on the corresponding sides of the surface of the connecting post. Elastic tooth plates are respectively fixedly connected to the corresponding sides of the inner wall of the mounting groove. The inner ends of the elastic tooth plates engage with the engagement tooth grooves. The length of the hinge unit can be adjusted by controlling the distance between the first connecting block and the second connecting block.

[0010] Furthermore, the adjustment frame includes connecting plates located on the upper and lower sides, with reinforcing plates fixedly connected between the two ends of the upper and lower connecting plates respectively; a first sliding plate and a second sliding plate are respectively provided on the outer side of the connecting plates and are slidably connected to each other, with a braking structure connecting the first sliding plate and the second sliding plate; a limit rod is fixedly connected to both ends of the lower connecting plate and one end of the upper connecting plate respectively; an adjustment screw is rotatably connected to the other end of the upper connecting plate respectively; the limit rod is slidably connected to the corresponding second sliding plate along the axial direction; an adjustment knob is fixedly connected to the middle of the adjustment screw and the two sides of the adjustment screw are threadedly connected to the corresponding second sliding plate respectively; by rotating the adjustment screw, two adjacent second sliding plates can be driven to move synchronously relative to each other.

[0011] The surface of the first slide plate is provided with inclined grooves. The upper and lower ends of the outermost first connecting block and the second connecting block are fixedly connected with connecting pins. The connecting pins slide in cooperation with the inclined grooves. The first slide plate can move with the second slide plate under the action of the braking structure. When the first slide plate moves, the outermost first connecting block and the second connecting block can close inward through the sliding cooperation between the inclined groove and the connecting pin.

[0012] Furthermore, the first slide plate has grooves at both its front and rear ends, and the corresponding second slide plate has slide plates fixedly connected to its front and rear ends. The slide plates are slidably connected to the grooves. The inner sides of the corresponding ends of the first and second slide plates have mounting grooves with openings at both ends. The two ends of the mounting grooves are axially slidably connected to reinforcing cylinders. The two corresponding reinforcing cylinders are threadedly connected to a reinforcing screw. The threaded portions at both ends of the reinforcing screw rotate in opposite directions. When the reinforcing screw rotates, it can drive the reinforcing cylinders to move outward to fix the slide plate. The middle part of the reinforcing screw is coaxially fixedly connected to a first connecting bevel gear. The upper side of the first connecting bevel gear meshes with a second connecting bevel gear. The upper side of the second connecting bevel gear is coaxially fixedly connected to an internal hexagonal nut. The internal hexagonal nut is rotatably connected to the outer end of the first slide plate.

[0013] Furthermore, a stabilizing bar is fixedly connected between the two outermost corresponding first sliding plates.

[0014] Furthermore, the connecting hoop includes an arc-shaped hoop with a notch and a connecting frame fixedly connected to the notch of the arc-shaped hoop. The connecting frame closes the arc-shaped hoop, and the hinge shafts of the hinge units are rotatably connected to the surface of the connecting frame.

[0015] Furthermore, a fixed toothed plate that can move radially along the protective tube is slidably connected to the inner side of the connecting frame. The fixed toothed plate has fixed teeth at one end corresponding to the protective tube to improve the fixing effect between the fixed toothed plate and the protective tube. A mounting frame is fixedly connected to the other end of the fixed toothed plate. A sliding frame is connected to the inner sliding rod of the mounting frame. A storage spring is fixedly connected between the sliding frame and the mounting frame. A swing plate is provided on the inner side of the connecting frame. The middle part of the swing plate is rotatably connected to the inner wall of the sliding frame. A hinge rod is hinged to one end of the swing plate facing the sliding frame. The other end of the hinge rod is hinged to the sliding frame. When the swing plate swings, the sliding block can be pushed to move towards the protective tube through the hinge rod, so that the fixed toothed plate can press against the surface of the protective tube. Stop bars are provided on both sides of the swing plate. The stop bars are fixedly connected to the inner wall of the connecting frame. The two stop bars are set at different heights.

[0016] Furthermore, key-shaped holes are respectively opened at both ends of the rear reinforcing plate, and fixing cylinders are respectively provided inside the key-shaped holes. Support arms are fixedly connected to both sides of the opening on the surface of the reinforcing plate of the fixing cylinder. When the fixing cylinder is installed into the key-shaped hole, the support arms press against the surface of the pressure plate. The fixing cylinder has a conical structure, and a fixing post is threadedly connected inside the fixing cylinder. Multiple openings are opened along the axial direction on the surface of the fixing cylinder. When the fixing post moves into the fixing cylinder during rotation, it can push the outer wall of the fixing cylinder outward. The connecting end of the fixing cylinder is provided with an internal hexagonal groove.

[0017] Furthermore, the surface of the fixed cylinder is provided with multiple layers of annular ratchet grooves, and the corresponding two sides of the connecting end of the fixed cylinder are respectively provided with limiting grooves, and the inner wall of the key-shaped hole is respectively provided with limiting teeth that mesh with the limiting grooves.

[0018] Furthermore, the outer ends of the support arms are respectively fixedly connected with mating pins, and the surfaces of the reinforcing plates corresponding to the mating pins are respectively hinged with swingable force-saving plates. The inner ends of the force-saving plates are respectively fixedly connected with grooved plates, and the surfaces of the grooved plates are respectively provided with connecting grooves. The mating pins are respectively slidably engaged with the connecting grooves. When the force-saving plates swing, they can drive the fixed cylinder to move through the sliding engagement between the connecting grooves and the mating pins.

[0019] This invention features a novel structure, ingenious design, and simple and convenient operation, offering the following advantages compared to existing technologies:

[0020] 1. This application adopts a hybrid structure combining hollow optical fiber and multi-core optical fiber. The hollow optical fiber is designed based on the anti-resonance principle, which not only significantly reduces transmission loss but also breaks through the nonlinear Shannon limit. It can simultaneously and stably transmit multi-channel tunnel monitoring data, effectively avoid signal congestion and delay, ensure the real-time performance and accuracy of monitoring data, further improve the reliability of the sensing system, and meet the core requirements of large-scale and high-precision tunnel monitoring.

[0021] 2. In use, the adjusting frame drives the second and first sliding plates to move synchronously through the threaded transmission. Combined with the sliding cooperation between the inclined groove and the connecting pin, it can drive the hinge unit to retract inward, thereby causing the protective tube to bend into an arc shape that fits the inner wall of the tunnel. At the same time, the length of the hinge unit is adjustable, which can accurately adapt to the bending radius of different tunnel sections without the need for additional auxiliary supports. The protective spring between the protective tube and the protective sleeve can absorb the impact force generated by tunnel vibration and surrounding rock deformation through elastic deformation, avoiding rigid impact that could cause fiber deformation or breakage, and ensuring the structural integrity of the cable under complex working conditions. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of a hollow fiber optic sensing hybrid cable for tunnel monitoring according to the present invention.

[0023] Figure 2 This is a schematic diagram of the hybrid cable structure of a hollow fiber optic sensing hybrid cable for tunnel monitoring according to the present invention.

[0024] Figure 3 This is a schematic diagram of the hollow optical fiber structure of a hollow optical fiber sensing hybrid cable for tunnel monitoring according to the present invention.

[0025] Figure 4 This is a schematic diagram of the hybrid cable installation structure of a hollow fiber optic sensing hybrid cable for tunnel monitoring according to the present invention.

[0026] Figure 5 This is a schematic diagram of the reinforcement structure of a hollow fiber optic sensing hybrid cable for tunnel monitoring according to the present invention.

[0027] Figure 6 This is a schematic diagram of the hinged unit installation structure of a hollow fiber optic sensing hybrid cable for tunnel monitoring according to the present invention.

[0028] Figure 7 This is a schematic diagram of the installation structure of the first and second slide plates of a hollow fiber optic sensing hybrid cable for tunnel monitoring according to the present invention.

[0029] Figure 8 This is a schematic diagram of the reinforcement screw installation structure of a hollow fiber optic sensing hybrid cable for tunnel monitoring according to the present invention.

[0030] Figure 9 This is a schematic diagram of the articulated unit structure of a hollow fiber optic sensing hybrid cable for tunnel monitoring according to the present invention.

[0031] Figure 10 This is a schematic diagram of the connection post installation structure of a hollow fiber optic sensing hybrid cable for tunnel monitoring according to the present invention.

[0032] Figure 11 This is a schematic diagram of the fixed toothed plate installation structure of a hollow fiber optic sensing hybrid cable for tunnel monitoring according to the present invention.

[0033] Figure 12 for Figure 11 A magnified view of part A.

[0034] Figure 13 This is a schematic diagram of the connection clamp installation structure of a hollow fiber optic sensing hybrid cable for tunnel monitoring according to the present invention.

[0035] Figure 14 This is a schematic diagram of the fixed cylinder installation structure of a hollow fiber optic sensing hybrid cable for tunnel monitoring according to the present invention.

[0036] Figure 15This is a first schematic diagram of a fixed post installation structure for a hollow fiber optic sensing hybrid cable used for tunnel monitoring according to the present invention.

[0037] Figure 16 This is a second schematic diagram of a fixed post installation structure for a hollow fiber optic sensing hybrid cable for tunnel monitoring according to the present invention.

[0038] Figure 17 This is a schematic diagram of the limiting tooth groove structure of a hollow fiber optic sensing hybrid cable for tunnel monitoring according to the present invention.

[0039] Numbering in the diagram: 1-Hybrid cable, 2-Multi-core optical fiber, 3-Reinforcing core, 4-Fiber grease, 5-Sheath, 6-Cable grease, 7-Protective tape, 8-Protective sleeve, 9-Coating layer, 10-Outer cladding, 11-Microstructure inner cladding, 12-Hollow fiber core, 13-Protective tube, 14-Protective spring, 15-Connecting clamp, 16-First connecting block, 17-Second connecting block, 18-Connecting pin, 19-Connecting plate, 20-Limiting rod, 21-Adjusting spring, 22-Adjusting knob, 23-Slide plate, 24-Reinforcing cylinder, 25-Inclined groove, 26-Reinforcing screw, 27-First connecting bevel gear, 28-Second connecting bevel gear, 2 9-Hex socket nut, 30-Connecting post, 31-Meshing tooth groove, 32-Elastic toothed plate, 33-Baffle, 34-Connecting frame, 35-Fixed toothed plate, 36-Fixed tooth, 37-Swing plate, 38-Stop bar, 39-Hinge rod, 40-Mounting frame, 41-Storage spring, 42-Sliding frame, 43-Reinforcing plate, 44-Key hole, 45-Limiting tooth groove, 47-Matching pin, 48-Effort-saving plate, 49-Groove plate, 50-Connecting groove, 51-Fixed cylinder, 52-Fixed post, 53-Connecting end, 54-Hex socket groove, 55-Stabilizing rod, 56-First sliding plate, 57-Second sliding plate, 58-Hollow fiber cable. Detailed Implementation

[0040] The following are specific embodiments of the present invention, and the technical solutions of the present invention will be further described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0041] like Figure 1-17 As shown, this invention provides a hollow-core fiber optic sensing hybrid cable for tunnel monitoring, comprising hollow and solid optical fibers. The central portion of the hollow fiber is a hollow channel; this hollow region is the primary medium for optical signal transmission and is typically filled with air, but can also be filled with other gases (such as inert gases) or liquids depending on specific application requirements. This design allows over 99% of the light energy to propagate in the low-refractive-index air / gas, fundamentally reducing material absorption loss and nonlinear effects, and enabling signal transmission at near-light speed.

[0042] The cladding consists of an outer cladding 10 and a microstructure inner cladding 11. The microstructure inner cladding 11 is not a homogeneous medium with a low refractive index as in traditional optical fibers, but rather a precision array of microstructures made of a high refractive index material, such as quartz glass. These microstructures, surrounding the hollow fiber core 12, form a "reflection barrier" for optical signals. It is the geometry, size, and arrangement of these microstructures that determine the optical fiber's guiding performance.

[0043] Similar to traditional optical fibers, the outermost layer of hollow-core optical fibers is a protective coating layer 9, typically composed of polymer materials such as acrylate or polyimide. Its main function is to provide mechanical protection for the fragile glass structure, enhancing its flexibility and durability, and resisting the effects of the external environment;

[0044] Multiple solid optical fibers are aggregated together, with an outer sheath 5. The sheath 5 is filled with fiber grease 4 to form a multi-core optical fiber 2. Multiple hollow optical fibers and multi-core optical fibers 2 are evenly distributed in a ring, with a reinforcing core 3 at the center. Cable grease 6 is filled between the multi-core optical fibers 2, hollow optical fibers, and reinforcing core 3, and a multi-layer spiral protective tape 7 is wrapped around the outer layer to tightly wrap the optical fibers. A protective sleeve 8 is provided on the outer layer of the protective tape 7, and a protective tube 13 is provided on the outer side of the protective sleeve 8. A protective spring 14 is sleeved between the protective tube 13 and the protective sleeve 8. Multiple reinforcement components are installed on the surface of the protective sleeve 8. The reinforcing core 3 is made of high-strength fiber material, and its core function is to provide axial support for the entire hybrid cable 1 through its own rigidity, resisting external forces such as tension and compression in the tunnel environment, and preventing the optical fiber from being deformed by force, thus affecting the sensing accuracy and transmission performance. The hollow optical fiber adopts an anti-resonance structure design, which can effectively reduce the transmission The cable grease 6 and fiber grease 4 are waterproof, moisture-proof, buffering, and have excellent sealing properties. The cable grease 6 is filled between the multi-core optical fiber 2, the hollow optical fiber, and the reinforcing core 3 to form a sealed buffer layer, reducing friction and collision between optical fibers and preventing water ingress. The fiber grease 4 is filled inside the sleeve 5 to specifically protect the solid optical fiber bundle, further enhancing the sealing and preventing moisture intrusion that could lead to optical fiber loss. The protective tape 7 is spirally wound to tightly bind the internal optical fiber bundle with the pre-tightening force generated by the winding, while also enhancing the torsional resistance of the hybrid cable 1. The protective spring 14 is sleeved between the protective tube 13 and the protective sleeve 8. The elastic deformation of the spring absorbs the impact force generated by the deformation and vibration of the surrounding rock in the tunnel, achieving flexible protection for the internal optical fiber and preventing the optical fiber from breaking due to rigid impact, thus ensuring the stability of the hybrid cable 1 in complex tunnel environments.

[0045] The reinforcement includes multiple connecting clamps 15 fitted onto the surface of the protective tube 13, hinge units connected to the upper and lower sides of the connecting clamps 15, and a retractable adjustment frame; two adjacent hinge units are hinged to each other, and the outermost hinge unit is connected to the adjustment frame. When the adjustment frame retracts inward, it can drive the hinged units to retract inward into an arc shape, and under the linkage of the connecting clamps 15, it drives the protective tube 13 to bend into an arc shape; the length of a single hinge unit is adjustable.

[0046] The reinforcement components are used to adapt and fix the shape of the hybrid cable 1, ensuring the stability of the hybrid cable 1 after it is attached to the inner wall of the tunnel, thereby ensuring the integrity of the hollow optical fiber anti-resonance structure and avoiding the reduction of transmission loss and high bandwidth performance due to shape deviation. The connecting clamp 15 serves as the connecting carrier between the hinge unit and the protective tube 13. It is attached to the surface of the protective tube 13 through a ring-shaped structure to ensure effective force transmission. The hinge structure between adjacent hinge units adopts a rotatable connection design, which allows it to have multiple degrees of freedom of movement. When the adjustment frame retracts, it will generate a centripetal pull on the outermost hinge unit. This pull is transmitted to each hinge unit in sequence through the hinge point, causing the originally linearly distributed hinge units to gradually converge into an arc shape. Then, the connecting clamp 15 drives the protective tube 13 to bend synchronously to adapt to the arc contour of the inner wall of the tunnel. The length of the hinge unit is adjustable. The extension and retraction of a single hinge unit can be flexibly adjusted according to the different bending radii of the tunnel to ensure that the force on each component is uniform during bending, avoid local stress concentration that damages the optical fiber structure, and ensure stable transmission performance.

[0047] The hinge unit includes a first connecting block 16 and a second connecting block 17. The first connecting block 16 and the second connecting block 17 in adjacent hinge units are hinged to each other. Connecting posts 30 are respectively provided on the upper and lower sides of the inner ends of the first connecting block 16 and the second connecting block 17 in the same hinge unit. Baffles 33 are respectively fixedly connected to both ends of the connecting posts 30. The interior of the first connecting block 16 and the second connecting block 17 is provided with mounting grooves that can slide with the baffles 33. The inner end of the mounting groove is provided with an opening that can slide with the connecting post 30. The baffles 33 are slidably connected in the mounting groove. The corresponding sides of the surface of the connecting post 30 are provided with meshing tooth grooves 31. The corresponding sides of the inner wall of the mounting groove are respectively fixedly connected with elastic tooth plates 32. The inner ends of the elastic tooth plates 32 mesh with the meshing tooth grooves 31. The length of the hinge unit can be adjusted by controlling the distance between the first connecting block 16 and the second connecting block 17.

[0048] The length adjustment principle of the articulated unit is based on the sliding fit between the connecting post 30 and the mounting groove and the meshing positioning of the elastic toothed plate 32. Its adjustment accuracy directly affects the accuracy of the bending shape of the hybrid cable 1, thereby ensuring the stability of the hollow fiber anti-resonant structure and avoiding increased transmission loss due to shape deviation. When length adjustment is required, the first connecting block 16 and the second connecting block 17 are pulled outwards or inwards. The connecting post 30 slides along the opening in the mounting groove, while the baffle 33 slides synchronously in the mounting groove, serving as a guide and limiter to prevent the first connecting block 16 and the second connecting block 17 from disengaging. The meshing toothed groove 31 on the surface of the connecting post 30 meshes with the inner edge of the mounting groove. The elastic toothed plates 32 of the wall mesh with each other. Under the action of elastic force, the elastic toothed plates 32 always fit tightly against the meshing tooth grooves 31. When adjusted to the target length, the tooth ends of the elastic toothed plates 32 are embedded in the corresponding meshing tooth grooves 31 to form a positioning lock, preventing the articulated unit from extending or retracting on its own during use, ensuring the stability of the hybrid cable 1, and thus maintaining high bandwidth transmission performance. The first connecting block 16 and the second connecting block 17 of adjacent articulated units are connected by a hinge shaft. The hinge shaft is made of wear-resistant alloy material to ensure that it can maintain stable connection performance during repeated rotation, realize smooth force transmission, and avoid the overall stability of the hybrid cable 1 due to component wear.

[0049] The adjustment frame includes connecting plates 19 located on the upper and lower sides, with reinforcing plates 43 fixedly connected between the two ends of the upper and lower connecting plates 19 respectively; a first sliding plate 56 and a second sliding plate 57 slidably connected to each other are respectively provided on the outer side of the connecting plates 19, and a braking structure is connected between the first sliding plate 56 and the second sliding plate 57; a limit rod 20 is fixedly connected to both ends of the lower connecting plate 19 and one end of the upper connecting plate 19 respectively; an adjustment screw is rotatably connected to the other end of the upper connecting plate 19; the limit rod 20 is slidably connected to the corresponding second sliding plate 57 along the axial direction; an adjustment knob 22 is fixedly connected to the middle of the adjustment screw, and both sides of the adjustment screw are threadedly connected to the corresponding second sliding plate 57 respectively; by rotating the adjustment screw, two adjacent second sliding plates 57 can be driven to move synchronously relative to each other;

[0050] The contraction effect of the adjustment frame is based on the combination of threaded transmission and limit guidance. Its transmission stability directly affects the smoothness of the bending process of the hybrid cable 1, thereby protecting the hollow optical fiber anti-resonant structure and avoiding increased transmission loss due to uneven force. The reinforcing plate 43 and the connecting plate 19 form a rigid frame structure, providing stable support for the entire adjustment frame, preventing deformation during adjustment, and ensuring the accuracy of the hybrid cable 1 shape adjustment. The threads on both sides of the adjustment screw have opposite directions and mesh with the threads of the corresponding second sliding plate 57. When the adjustment knob 22 is rotated, the adjustment screw rotates synchronously. Under the action of the reverse threads, the second sliding plates 57 on both sides will... The limiting rod 20 moves synchronously relative to the second sliding plate 57 to achieve the contraction or expansion of the adjustment frame. The sliding fit between the limiting rod 20 and the second sliding plate 57 adopts a high-precision gap design, which not only ensures the smooth movement of the second sliding plate 57, but also restricts the rotational freedom of the second sliding plate 57, ensuring that it moves only along the axial direction. This ensures the stable transmission of the contraction force of the adjustment frame and avoids the transmission performance of the optical fiber being affected by force fluctuations. The braking structure is used to lock the relative position of the first sliding plate 56 and the second sliding plate 57 after the adjustment frame reaches the target contraction state, preventing them from moving on their own and ensuring the stability of the hybrid cable 1 after it is attached to the inner wall of the tunnel, maintaining the high bandwidth transmission effect.

[0051] The surface of the first slide plate 56 is provided with inclined grooves 25. The upper and lower ends of the outermost first connecting block 16 and the second connecting block 17 are respectively fixedly connected with connecting pins 18. The connecting pins 18 are slidably engaged with the inclined grooves 25. The first slide plate 56 can move with the second slide plate 57 under the action of the braking structure. When the first slide plate 56 moves, the outermost first connecting block 16 and the second connecting block 17 can close inward through the sliding engagement of the inclined grooves 25 and the connecting pins 18.

[0052] The inclined groove 25 is designed with an inclination angle, and its inclination direction forms an angle with the moving direction of the first slide plate 56. When the first slide plate 56 moves synchronously with the second slide plate 57, the inner wall of the inclined groove 25 will generate a lateral thrust on the connecting pin 18. The connecting pin 18 is fixed on the outermost first connecting block 16 and second connecting block 17. This lateral thrust will be converted into a torque that causes the first connecting block 16 and the second connecting block 17 to rotate inward, thereby driving the adjacent hinge units to retract in sequence. The inner wall of the inclined groove 25 is smoothed to reduce the friction during the sliding process of the connecting pin 18 and ensure transmission efficiency. At the same time, the connecting pin 18 adopts a rolling bearing design to further reduce wear, extend service life, and ensure the stability of the hybrid cable 1 in long-term use.

[0053] The first slide plate 56 has grooves at both its front and rear ends. The corresponding second slide plate 57 has slide plates 23 fixedly connected to its front and rear ends. The slide plates 23 slide in slidable fit with the grooves. The inner side of the corresponding end of the first slide plate 56 and the second slide plate 57 has mounting grooves with openings at both ends. The two ends of the mounting grooves are axially slidably connected to reinforcing cylinders 24. The two corresponding reinforcing cylinders 24 are threadedly connected to a reinforcing screw 26. The threaded portions at both ends of the reinforcing screw 26 rotate in opposite directions. When the reinforcing screw 26 rotates, it can drive the reinforcing cylinders 24 to move outward to fix the slide plate 23. The middle part of the reinforcing screw 26 is coaxially fixedly connected to a first connecting bevel gear 27. The upper side of the first connecting bevel gear 27 is meshed with a second connecting bevel gear 28. The upper side of the second connecting bevel gear 28 is coaxially fixedly connected to an internal hexagonal nut 29. The internal hexagonal nut 29 is rotatably connected to the outer end of the first slide plate 56.

[0054] The sliding engagement between the slide plate 23 and the groove provides guidance for the relative movement of the first slide plate 56 and the second slide plate 57, ensuring movement accuracy. The reverse threads at both ends of the reinforcing screw 26 mesh with the threads of the reinforcing cylinder 24. When the second connecting bevel gear 28 is rotated through the internal hex nut 29, the second connecting bevel gear 28 drives the meshing first connecting bevel gear 27 to rotate, thereby causing the reinforcing screw 26 to rotate synchronously. Under the action of the reverse threads, the two reinforcing cylinders 24 will move outward synchronously and press tightly against the inner wall of the slide plate 23. The first slide plate 56 and the second slide plate 57 are locked and fixed by friction. The bevel gear transmission structure changes the direction of force transmission, allowing the operator to rotate the internal hex nut 29 from the side using an internal hex tool, making operation more convenient. At the same time, the bevel gear adopts a high-precision meshing design to ensure the stability and accuracy of transmission, avoid locking failure due to transmission deviation, ensure the long-term stable operation of the hybrid cable 1 in the tunnel environment, and maintain high bandwidth transmission performance.

[0055] A stabilizing rod 55 is fixedly connected between the two corresponding upper and lower first sliding plates 56 on the outermost side. The two ends of the stabilizing rod 55 are fixedly connected to the corresponding upper and lower first sliding plates 56 to form a lateral support structure. This structure can ensure that the two upper and lower first sliding plates 56 remain synchronized during movement, avoiding offset or tilting caused by uneven force on one side. This ensures that the closing action of the hinge units on both sides is consistent, making the bending shape of the hybrid cable 1 more regular and the fit with the tunnel wall higher. This ensures that the hollow optical fiber anti-resonant structure is not damaged. At the same time, the stabilizing rod 55 can also enhance the overall rigidity of the adjustment frame, resist the lateral impact force in the tunnel environment, protect the internal transmission components, prevent the deformation of components from affecting the sealing of the hybrid cable 1, avoid water ingress that could damage the optical fiber performance, and further ensure the transmission performance and long-term stability of the hybrid cable 1.

[0056] The connecting hoop 15 includes an arc-shaped hoop with a notch and a connecting frame 34 fixedly connected to the notch of the arc-shaped hoop. The connecting frame 34 closes the arc-shaped hoop, and the hinge shafts of the hinge units are rotatably connected to the surface of the connecting frame 34.

[0057] The arc-shaped hoop is made of elastic material, and its notch design makes it easy to fit onto the surface of the protective tube 13. After fitting, the notch is closed by the connecting frame 34, so that the arc-shaped hoop tightly hugs the protective tube 13. The elastic restoring force of the arc-shaped hoop generates radial pressure to achieve initial fixation. The connecting frame 34 not only serves to close the notch, but also acts as the mounting base for the hinge unit. At the same time, the connecting frame 34 and the arc-shaped hoop are integrally molded to enhance the connection strength and prevent breakage or deformation during force transmission. This ensures the stability of the hybrid cable 1, thereby maintaining the integrity of the hollow optical fiber anti-resonance structure, reducing transmission loss, and ensuring high-bandwidth transmission performance.

[0058] The inner side of the connecting frame 34 is slidably connected to a fixed toothed plate 35 that can move radially along the protective tube 13. Fixed teeth 36 are respectively provided at one end of the fixed toothed plate 35 corresponding to the protective tube 13 to improve the fixing effect between the fixed toothed plate 35 and the protective tube 13. The other end of the fixed toothed plate 35 is fixedly connected to a mounting frame 40. A sliding frame 42 is slidably connected to the inner side of the mounting frame 40. A storage spring 41 is fixedly connected between the sliding frame 42 and the mounting frame 40. A swing arm is provided on the inner side of the connecting frame 34. The middle part of the swing plate 37 is rotatably connected to the inner wall of the sliding frame 42. One end of the swing plate 37 facing the sliding frame 42 is hinged to a hinge rod 39, and the other end of the hinge rod 39 is hinged to the sliding frame 42. When the swing plate 37 swings, the sliding frame 42 can be pushed to move towards the protective tube 13 through the hinge rod 39, so that the fixed tooth plate 35 can press against the surface of the protective tube 13. The two sides of the swing plate 37 are respectively provided with a stop rod 38, which is fixedly connected to the inner wall of the connecting frame 34. The two stop rods 38 are set at different heights.

[0059] The storage spring 41 is always in a compressed state, providing a continuous thrust to the sliding frame 42. This thrust is transmitted to the swing plate 37 through the hinge rod 39, causing the swing plate 37 to tend to rotate towards the protective tube 13. The rotation connection point in the middle of the swing plate 37 serves as a fulcrum. When the hinge unit retracts and forces the connecting frame 34, the swing plate 37 will rotate around the fulcrum, further pushing the sliding frame 42 towards the protective tube 13 through the hinge rod 39, thereby causing the fixed toothed plate 35 to press against the protective tube 13. The ends of the fixed toothed plate 35... The fixing teeth 36 adopt a serrated design, which can be embedded in the anti-slip texture on the surface of the protective tube 13 to increase friction and prevent the connecting clamp 15 from sliding on the protective tube 13, thus ensuring the stability of the hybrid cable 1. The high and low baffles 38 are used to limit the rotation angle of the swing plate 37, so as to avoid excessive rotation of the swing plate 37, which would cause excessive pressure on the fixing tooth plate 35 and damage the protective tube 13 or the optical fiber. At the same time, it ensures that the clamping force of the fixing tooth plate 35 is within a reasonable range, maintains the transmission performance and stability of the hybrid cable 1, and ensures that the high-bandwidth signal transmission is not affected.

[0060] The rear reinforcing plate 43 has key-shaped holes 44 at both ends, and a fixing cylinder 51 is provided inside the key-shaped hole 44. The fixing cylinder 51 is located at the opening on the surface of the reinforcing plate 43 and is fixedly connected to the two sides of the opening. When the fixing cylinder 51 is installed into the key-shaped hole 44, the supporting arms press against the surface of the pressure plate. The fixing cylinder 51 has a conical structure and a fixing post 52 is threaded inside the fixing cylinder 51. The surface of the fixing cylinder 51 has multiple openings along the axial direction. When the fixing post 52 moves into the fixing cylinder 51 during rotation, it can push the outer wall of the fixing cylinder 51 outward. The connecting end 53 of the fixing cylinder 51 has an internal hexagonal groove 54. The conical structure and threaded feed cause the fixing cylinder 51 to expand, and its fixing strength directly affects the connection stability between the hybrid cable 1 and the tunnel fixing structure, thereby ensuring the optical fiber transmission performance. The fixing cylinder 51 adopts a conical design and has an axial opening on its surface, giving it a certain elastic expansion capacity. When the fixing post 52 is rotated through the internal hexagonal groove 54, the fixing post 52 moves into the fixing cylinder 51 under the action of the thread. The conical end of the fixing post 52 will generate a radial expansion force on the inner wall of the fixing cylinder 51, causing the outer wall of the fixing cylinder 51 to open outward and press tightly against the inner wall of the key hole 44. The friction force is used to fix the fixing cylinder 51 and the reinforcing plate 43, ensuring the installation stability of the hybrid cable 1 in the tunnel and avoiding positional displacement due to vibration. The function of the support arm is to provide positioning support when the fixing cylinder 51 is installed, so that the fixing cylinder 51 can be accurately embedded into the key hole 44. At the same time, the support arm presses on the surface of the pressure plate, further enhancing the stability and sealing of the fixation.

[0061] The surface of the fixed cylinder 51 is provided with multiple annular ratchet grooves. Limiting grooves 45 are respectively provided on both sides of the connecting end 53 of the fixed cylinder 51. Limiting teeth that mesh with the limiting grooves 45 are respectively provided on the inner wall of the key-shaped hole 44. The ratchet grooves and limiting teeth can achieve unidirectional locking and anti-loosening. The limiting grooves 45 and the limiting teeth on the inner wall of the key-shaped hole 44 mesh with each other to achieve circumferential positioning of the fixed cylinder 51, preventing the fixed cylinder 51 from rotating during use. This avoids the hybrid cable 1 from shifting due to rotation, damaging the hollow fiber anti-resonance structure, and increasing transmission loss. The ratchet teeth of the ratchet groove are designed with an inclination, allowing the fixed cylinder 51 to be inserted only into the key-shaped hole 44. When pulled out in the opposite direction, the ratchet teeth will engage with the limiting teeth, playing an anti-loosening role and preventing the fixed cylinder 51 from loosening and falling off due to tunnel vibration. This ensures stable installation of the hybrid cable 1, maintains high bandwidth transmission performance, and overcomes the nonlinear Shannon limit.

[0062] The outer ends of the support arms are respectively fixedly connected to mating pins 47. The surfaces of the reinforcing plates 43 corresponding to the mating pins 47 are respectively hinged to swingable force-saving plates 48. The inner ends of the force-saving plates 48 are respectively fixedly connected to groove plates 49. The surfaces of the groove plates 49 are respectively provided with connecting grooves 50. The mating pins 47 are respectively slidably engaged with the connecting grooves 50. When the force-saving plates 48 swing, they can drive the fixed cylinder 51 to move through the sliding engagement between the connecting grooves 50 and the mating pins 47. Using the lever principle, the hinge point of the force-saving plate 48 serves as the fulcrum. Its length design conforms to the lever principle of saving effort. Operators only need to apply a small force to swing the force-saving plate 48 to generate a large pulling or pushing force at the slot plate 49, reducing the difficulty of installation. The connecting groove 50 on the surface of the slot plate 49 slides with the mating pin 47. When the force-saving plate 48 swings, the inner wall of the connecting groove 50 will generate an axial force on the mating pin 47. This force drives the fixed cylinder 51 to move axially along the key hole 44, realizing the insertion or removal of the fixed cylinder 51, ensuring that the fixed cylinder 51 is installed in place, ensuring the stable connection between the hybrid cable 1 and the tunnel structure, further improving the transmission efficiency, making the installation and disassembly of the fixed cylinder 51 more convenient, ensuring the long-term stable operation of the hybrid cable 1, and maintaining excellent transmission performance.

[0063] When this device is used in a tunnel monitoring scenario, the shape of the hybrid cable 1 must first be adjusted according to the arc-shaped contour of the tunnel wall. The operator drives the adjusting screw to rotate by turning the adjusting knob 22 on the adjusting frame. Because the threads on both sides of the adjusting screw rotate in opposite directions, it will drive the second sliding plates 57 on both sides to move synchronously relative to each other along the limiting rod 20. During the movement of the second sliding plate 57, the first sliding plate 56 moves synchronously through the braking structure. The inclined groove 25 on the surface of the first sliding plate 56 slides with the connecting pin 18 of the outermost hinge unit, generating a lateral thrust to make the hinge unit retract inward. At the same time, the length of a single hinge unit can be adjusted by pulling the first connecting block 16 and the second connecting block 17 of the hinge unit, using the sliding fit between the connecting column 30 and the mounting groove and the meshing positioning of the elastic toothed plate 32 and the meshing toothed groove 31. Finally, under the linkage of the connecting clamp 15, the protective tube 13 is bent into an arc shape to fit the tunnel wall. The stabilizing rod 55 ensures that the upper and lower adjustment actions are synchronized, avoiding shape deviation and damage to the hollow optical fiber anti-resonance structure.

[0064] After the shape adjustment is completed, the adjustment frame is locked by the braking structure: rotating the internal hexagonal nut 29 drives the second connecting bevel gear 28 to rotate, which in turn drives the meshing first connecting bevel gear 27 and the reinforcing screw 26 to rotate. The reverse threads at both ends of the reinforcing screw 26 cause the reinforcing cylinder 24 to move outward and press against the sliding plate 23, thereby locking and fixing the first sliding plate 56 and the second sliding plate 57. Then, the fixing is installed by inserting the fixing cylinder 51 into the key hole 44 of the reinforcing plate 43. The swing-type effort-saving plate 48 pushes the fixing cylinder 51 into place by sliding the groove 50 of the slot plate 49 and the mating pin 47. The fixing column 52 is rotated to move it into the fixing cylinder 51, opening the outer wall of the fixing cylinder 51 and tightly fitting it with the key hole 44. The ratchet groove meshes with the limiting tooth to prevent loosening, and the support arm is pressed to enhance the sealing performance.

[0065] During operation, the hollow fiber hybrid cable 1 reduces transmission loss and achieves high-bandwidth sensing signal transmission through its anti-resonance structure; the cable grease 6, fiber grease 4, and protective structure prevent water ingress and ensure sealing. All components work together to maintain the stability of the hybrid cable 1, ensuring accurate and stable transmission of tunnel monitoring data.

[0066] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains can make various modifications or additions to the described specific embodiments or use similar methods to replace them.

Claims

1. A hollow core fiber sensing hybrid cable for tunnel monitoring comprising a hollow core fiber and a solid core fiber, characterized in that, A plurality of the solid optical fibers are aggregated together, an outer layer is provided with a sleeve (5), the inside of the sleeve (5) is filled with fiber paste (4), forming a multi-core optical fiber (2); a plurality of the hollow optical fibers and the multi-core optical fiber (2) are uniformly distributed in a ring shape, a reinforcing core (3) is arranged at the center position, the multi-core optical fiber (2), the hollow optical fiber and the reinforcing core (3) are filled with cable paste (6), and an outer layer is wound with a plurality of spiral distributed protective belts (7) to tightly wrap the optical fiber, the outer layer of the protective belt (7) is provided with a protective sleeve (8), the outer side of the protective sleeve (8) is provided with a protective tube (13), the protective tube (13) and the protective sleeve (8) are sleeved with a protective spring (14), and a plurality of reinforcing members are mounted on the surface of the protective sleeve (8); The reinforcing member comprises a plurality of connecting hoops (15) sleeved on the surface of the protective tube (13), hinged units connected to the upper and lower sides of the connecting hoops (15), and a retractable adjusting frame; the adjacent two hinged units are hingedly connected to each other, the outermost hinged unit is connected to the adjusting frame, and when the adjusting frame is retracted inward, the hingedly connected hinged units can be retracted inward in an arc shape, and the protective tube (13) is bent into an arc shape under the connection of the connecting hoops (15); the length of the single hinged unit is adjustable; The hinged unit comprises a first connecting block (16) and a second connecting block (17), the first connecting block (16) and the second connecting block (17) in adjacent hinged units are hingedly connected to each other, the upper and lower sides of the inner ends of the first connecting block (16) and the second connecting block (17) in the same hinged unit are respectively provided with connecting columns (30), the two ends of the connecting column (30) are respectively fixedly connected with baffle plates (33), the inner parts of the first connecting block (16) and the second connecting block (17) are respectively provided with mounting grooves capable of being slidably connected with the baffle plates (33), the inner ends of the mounting grooves are respectively provided with openings capable of being slidably connected with the connecting columns (30), and the baffle plates (33) are slidably connected in the mounting grooves; the surfaces of the connecting columns (30) are respectively provided with meshing tooth grooves (31) on the two sides corresponding to each other, the inner walls of the mounting grooves are respectively fixedly connected with elastic tooth plates (32) on the two sides corresponding to each other, the inner ends of the elastic tooth plates (32) are respectively engaged with the meshing tooth grooves (31), and the length of the hinged unit can be adjusted by controlling the spacing between the first connecting block (16) and the second connecting block (17); The adjusting frame comprises upper and lower connecting plates (19), and reinforcing plates (43) are fixedly connected between the two ends of the upper and lower connecting plates (19); the outer sides of the connecting plates (19) are respectively provided with first and second sliding plates (56, 57) which are in sliding connection with each other, and a brake structure is connected between the first and second sliding plates (56, 57); the two ends of the lower connecting plate (19) and one end of the upper connecting plate (19) are respectively fixedly connected with limiting rods (20), and the other end of the upper connecting plate (19) is rotatably connected with adjusting screws, the limiting rods (20) are in axial sliding connection with the corresponding second sliding plates (57), and the adjusting screws are fixedly connected with adjusting knobs (22) in the middle and are in threaded connection with the corresponding second sliding plates (57) at the two sides, and the two adjacent second sliding plates (57) can be synchronously relatively moved by rotating the adjusting screws; The surfaces of the first sliding plates (56) are respectively provided with inclined grooves (25), and the upper and lower ends of the outermost first and second connecting blocks (16, 17) are respectively fixedly connected with connecting pin shafts (18) which are in sliding connection with the inclined grooves (25), and the first sliding plates (56) can move along with the second sliding plates (57) under the connection of the brake structure, and the outermost first and second connecting blocks (16, 17) can be folded inwards by the sliding connection of the inclined grooves (25) and the connecting pin shafts (18) when the first sliding plates (56) move.

2. A hollow core fiber sensing hybrid cable for tunnel monitoring as claimed in claim 1, wherein: The front and rear ends of the first sliding plates (56) are respectively provided with sliding grooves, the front and rear ends of the corresponding second sliding plates (57) are respectively fixedly connected with sliding plates (23) which are in sliding connection with the sliding grooves, the inner sides of the corresponding ends of the first and second sliding plates (56, 57) are respectively provided with mounting grooves which are open at the front and rear ends, the inner ends of the mounting grooves are in axial sliding connection with reinforcing cylinders (24), the corresponding two reinforcing cylinders (24) are in threaded connection with a reinforcing screw (26), the threaded parts at the two ends of the reinforcing screw (26) are in opposite directions, the reinforcing cylinder (24) can be moved outwards to fix the sliding plate (23) when the reinforcing screw (26) rotates, the middle part of the reinforcing screw (26) is fixedly connected with a first connecting bevel gear (27), the upper side of the first connecting bevel gear (27) is in meshing connection with a second connecting bevel gear (28), the upper side of the second connecting bevel gear (28) is fixedly connected with an inner hexagonal nut (29) which is rotatably connected to the outer end of the first sliding plate (56).

3. A hollow core fiber sensing hybrid cable for tunnel monitoring as claimed in claim 1, wherein: The outermost upper and lower corresponding two first sliding plates (56) are fixedly connected with a stabilizing rod (55).

4. A hollow core fiber sensing hybrid cable for tunnel monitoring as claimed in claim 1, wherein: The connecting hoop (15) comprises an arc-shaped hoop with a notch and a connecting frame (34) fixedly connected at the notch of the arc-shaped hoop, the connecting frame (34) closes the arc-shaped hoop, and the hinge shafts of the hinge units are rotatably connected to the surfaces of the connecting frame (34).

5. A hollow core fiber sensing hybrid cable for tunnel monitoring as claimed in claim 4, wherein: The inner side of the connecting frame (34) is slidably connected with a fixed tooth plate (35) capable of moving along the radial direction of the protection pipe (13), and the fixed tooth plate (35) is provided with a fixed tooth (36) at one end corresponding to the protection pipe (13), so as to improve the fixing effect between the fixed tooth plate (35) and the protection pipe (13); the other end of the fixed tooth plate (35) is fixedly connected with a mounting frame (40), the inner side of the mounting frame (40) is slidably connected with a sliding frame (42), and the sliding frame (42) and the mounting frame (40) are fixedly connected with a force storage spring (41); the inner side of the connecting frame (34) is provided with an oscillating plate (37), the middle part of the oscillating plate (37) is rotatably connected with the inner wall of the sliding frame (42), one end of the oscillating plate (37) towards the sliding frame (42) is hingedly connected with a hinge rod (39), the other end of the hinge rod (39) is hingedly connected with the sliding frame (42), and when the oscillating plate (37) oscillates, the sliding block can be pushed to move towards the protection pipe (13) through the hinge rod (39), so that the fixed tooth plate (35) can abut against the surface of the protection pipe (13); the two sides of the oscillating plate (37) are provided with stop rods (38) respectively, the stop rods (38) are fixedly connected with the inner wall of the connecting frame (34), and the two stop rods (38) are arranged high and low.

6. A hollow core fiber sensing hybrid cable for tunnel monitoring as claimed in claim 1, wherein: The two ends of the rear reinforcing plate (43) are respectively provided with key-shaped holes (44), the inner sides of the key-shaped holes (44) are respectively provided with fixed cylinders (51), the fixed cylinders (51) are fixedly connected with supporting arms at both sides of the opening on the surface of the reinforcing plate (43), and the supporting arms are pressed on the surface of the pressing plate when the fixed cylinders (51) are installed into the key-shaped holes (44); the fixed cylinders (51) are in a conical structure, a fixed column (52) is screw-connected in the fixed cylinders (51), a plurality of openings are formed in the surface of the fixed cylinders (51) in the axial direction, and the outer wall of the fixed cylinders (51) can be expanded outward when the fixed column (52) moves into the fixed cylinders (51) during rotation; an inner hexagonal groove (54) is formed in the connecting end (53) of the fixed cylinder (51).

7. A hollow core fiber sensing hybrid cable for tunnel monitoring as claimed in claim 6, wherein: The surface of the fixed cylinder (51) is provided with a plurality of annular ratchet grooves, the connecting end (53) of the fixed cylinder (51) is respectively provided with a limiting tooth groove (45) at both sides corresponding to each other, and the inner wall of the key-shaped hole (44) is respectively provided with a limiting tooth meshing with the limiting tooth groove (45).

8. A hollow core fiber sensing hybrid cable for tunnel monitoring as claimed in claim 6, wherein: The outer ends of the supporting arms are respectively fixedly connected with matching pin shafts (47), the surfaces of the reinforcing plates (43) corresponding to the matching pin shafts (47) are respectively hingedly connected with labor-saving plates (48) capable of oscillating, the inner ends of the labor-saving plates (48) are respectively fixedly connected with groove plates (49), the surfaces of the groove plates (49) are respectively provided with connecting grooves (50), and the matching pin shafts (47) are respectively slidably matched with the connecting grooves (50), so that the fixed cylinder (51) can be driven to move through the sliding matching of the connecting grooves (50) and the matching pin shafts (47) when the labor-saving plates (48) oscillate.

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