A grating optical fiber protection device for breaking anti-slide pile head

Abstract

The utility model discloses a kind of grating optical fiber protection devices when breaking anti-slide pile head, including the pre-bundling of multiple grating optical fibers on the reinforcement cage main reinforcement of anti-slide pile is tied, further include the PVC sleeve of grating optical fiber outside sleeve;Multiple grating sensors are evenly arranged on grating optical fiber with interval, and adjacent grating sensor is provided with rope binding point;The length of PVC sleeve is at least more than one time over breaking pile area from the bottom of breaking pile area;Grating optical fiber is extended to pile bottom along main reinforcement after being worn out PVC sleeve. By the combination design of pre-bundling grating optical fiber on main reinforcement and external PVC sleeve, grating optical fiber and sensor are effectively physically protected when breaking anti-slide pile head, and can be embedded thin-walled steel pipe in PVC sleeve as backup protection according to actual demand, also can be inserted pitchy hemp silk in PVC sleeve and use impermeable adhesive tape to seal port to improve impermeability. The protection device structure is reasonable, has impermeable and moisture-proof performance, and overall reliability is high.

Description

Technical Field

[0001] This utility model relates to the field of slope engineering, specifically to a fiber optic grating protection device for the pile head of a ruptured anti-slide pile. Background Technology

[0002] Grating fiber optic sensing technology senses stress, strain, and temperature changes inside a structure by measuring the center wavelength drift of the grating. It has outstanding advantages such as resistance to electromagnetic interference, corrosion resistance, and the ability to achieve distributed long-term monitoring. It is especially suitable for safety monitoring of geotechnical engineering such as slopes, foundation pits, and anti-slide piles.

[0003] During the construction of anti-slide piles, the strength of the pile head is difficult to guarantee because the concrete rises upwards. In addition, during the concrete pouring process, soil and other impurities inevitably fall into the pile head. Therefore, in actual construction, the pile head is usually poured to a certain height above the design elevation and then removed after the pile is completed to ensure the quality and structural strength of the pile body.

[0004] The optical fiber and sensing node have low mechanical strength and are easily damaged during construction, especially in the pile head breaking stage after the anti-slide pile is completed. The fiber optic cable is often broken or the grating fails due to the chiseling operation, resulting in interruption of monitoring data and a significant increase in maintenance costs.

[0005] Therefore, effectively protecting the pre-embedded optical fiber from damage during the pile breaking process and ensuring its smooth progress in subsequent construction work such as crown beam wiring, binding, and sensor installation has become a key issue restricting the widespread application of this technology. To address this practical need, there is an urgent need to develop a dedicated protective device that can provide reliable protection for the optical fiber during pile breaking while also ensuring the convenience and continuity of subsequent construction. Utility Model Content

[0006] To address the aforementioned issues, this utility model aims to provide a grating fiber protection device for breaking the pile head of a sliding pile, thereby solving the problems of easy damage to the grating fiber when breaking the pile head, high maintenance costs, and difficulty in subsequent construction in the prior art.

[0007] To achieve this technical objective, the present invention provides a grating fiber optic protection device for the pile head of a broken anti-slide pile. This device protects the grating fiber optic cable inside the pile head in the broken pile area. The grating fiber optic cable is pre-tied to the main reinforcement of the anti-slide pile's steel cage and includes a PVC sleeve fitted over the grating fiber optic cable. A plurality of grating sensors are evenly spaced on the grating fiber optic cable, and rope binding points are located adjacent to the grating sensors. The length of the PVC sleeve extends at least twice the length of the broken pile area from the bottom of the broken pile area. After passing through the PVC sleeve, the grating fiber optic cable extends along the main reinforcement to the bottom of the pile.

[0008] Preferably, a thin-walled steel pipe may be nested inside the PVC sleeve, the length of which extends from the bottom of the pile breaking area to above the pile breaking area.

[0009] Preferably, the PVC sleeve is open at both ends, the inside of the PVC sleeve is filled with asphalt hemp fibers, and the outer side of the end of the PVC sleeve is wrapped with waterproof tape.

[0010] Preferably, an adhesive tape connection structure is provided between the PVC sleeve and the main reinforcement, and the adhesive tape connection structure is located at both ends of the PVC sleeve.

[0011] Preferably, the system also includes a sonic logging tube, which is welded inside the reinforcing cage and is at least 0.5 meters higher than the designed elevation of the pile. The bottom and opening of the sonic logging tube are both sealed.

[0012] Preferably, the number of grating optical fibers is 3, 6, or 15.

[0013] Preferably, the main reinforcement bars of the steel cage are mechanically connected, with staggered joints, and the number of joints in the same section does not exceed 50% of the total number of main reinforcement bars; the steel cage is also provided with stirrups, the lap length of the stirrups is 20 cm, and the lap joints of the stirrups are double-sided welded.

[0014] The beneficial effects of this utility model are as follows: The combination design of the grating optical fiber pre-tied to the main reinforcement and the external PVC sleeve provides effective physical protection for the core grating optical fiber and sensor when the anti-slip pile head is breached. Furthermore, a thin-walled steel pipe can be embedded inside the PVC sleeve as backup protection, or asphalt-impregnated hemp fibers can be stuffed inside the PVC sleeve and sealed with impermeable tape to improve seepage prevention performance. This protective device has a reasonable structure, combines seepage prevention and moisture-proof performance, facilitates subsequent cap beam construction, can adapt to various optical fiber layout requirements, and has high overall reliability. Attached Figure Description

[0015] Figure 1 This is a structural elevation view of the present invention;

[0016] Figure 2 This is a schematic diagram of the structure of this utility model;

[0017] Figure 3 This is a detailed view of the present invention.

[0018] In the diagram: 1. Main reinforcement; 2. Optical fiber grating; 3. Thin-walled steel pipe; 4. Optical fiber grating sensor; 5. Rope binding point; 6. Pipe breaking area; 7. PVC sleeve; 8. Asphalt hemp fiber; 9. Impermeable rubber sheet; 10. Rubber sheet connection structure; 11. Sonic logging pipe; 12. Stirrup. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. To provide a clear and complete description of the technical solution, the following embodiments are selected for illustration; these embodiments are only some embodiments of the present invention; other embodiments obtained based on this application without creative effort are all within the scope of protection of the present invention.

[0020] In the following embodiments, it should be noted that the terms "upper," "lower," "left," "right," "inner," "outer," "top / bottom," etc., are all based on the orientation or positional relationship shown in the accompanying drawings and are only for the purpose of clearly describing this embodiment. They do not indicate or imply that the device or element referred to must have a specific orientation, and therefore should not be construed as a limitation of this application. At the same time, the terms "first" and "second" in the embodiments are only used for descriptive purposes and do not represent an indication or implication of relative importance.

[0021] like Figure 1-3 As shown, the specific embodiment of this utility model is a grating fiber optic protection device for breaking the pile head of an anti-slide pile (hereinafter referred to as the "protection device"). This protection device is mainly used to provide effective protection for the pre-embedded grating fiber optic cable 2 and its sensor during the construction of anti-slide piles on slopes, especially when breaking the pile head, to prevent them from being damaged by mechanical impact, vibration or concrete debris, and at the same time facilitate the subsequent wiring and binding construction in the cap beam.

[0022] The protective device includes multiple grating optical fibers 2 pre-tied to the main reinforcement 1 of the anti-slide pile's steel cage, and a PVC sleeve 7 covering the grating optical fibers 2. Multiple grating sensors 4 are evenly spaced on the grating optical fibers 2. The grating sensors 4 have advantages such as long signal transmission distance, resistance to electromagnetic interference, and high durability, enabling them to obtain continuous and complete stress distribution data along the depth direction of the pile, providing detailed evidence for analysis. Rope binding points 5 for precise positioning and fixation are located near the sensors. The length of the PVC sleeve 7 is designed to extend at least twice the length of the broken pile area 6 from the bottom of the broken pile area 6. The extended PVC sleeve 7 ensures that even if the broken pile location is slightly offset or too deep, the optical fiber remains within the protection range of the sleeve 7, avoiding a "protection blind spot." After passing through the sleeve 7, the grating optical fibers 2 extend along the main reinforcement 1 to the bottom of the pile. The optical fibers form a complete monitoring path from the bottom of the pile to the top of the pile (crown beam), comprehensively reflecting the stress state of the anti-slide pile from the bottom embedded end to the top free end.

[0023] The protective device of this utility model may further include adding a thin-walled steel pipe 3 inside the PVC sleeve, performing anti-seepage sealing treatment on the inside of the PVC sleeve 7, and setting a tape connection structure 10 between the optical fiber and the main reinforcement 1. These together constitute a multi-layered, highly reliable protection system.

[0024] Specifically, the length of the thin-walled steel pipe 3 installed inside the PVC sleeve extends from the bottom of the broken pile area 6 to above the broken pile area 6. The thin-walled steel pipe 3 can serve as a backup protection for the system, protecting the internal grating optical fiber 2 in the event that the PVC sleeve 7 is accidentally damaged. It also provides targeted protection, reduces costs, and strengthens the most critical weak points through material composites and functional zoning, achieving the greatest reliability improvement with the least incremental cost.

[0025] The PVC sleeve 7 is open at both ends, and its interior is filled with asphalt-impregnated hemp fibers 8. The outer sides of the ends of the PVC sleeve 7 are wrapped with waterproof tape 9. Asphalt-impregnated hemp fibers 8, as a traditional and excellent waterproof sealing material, fill and seal the annular gap between the sleeve 7 and the optical fiber. The waterproof tape 9 reinforces the seal and secures the internal filling. It forms an elastic film that further prevents the intrusion of fluids such as moisture and mud, and ensures that the internal asphalt-impregnated hemp fibers 8 will not detach or shift under the impact of concrete pouring.

[0026] In order to fix the PVC sleeve 7 and prevent the PVC sleeve 7 from sliding or rotating along the axial direction of the grating optical fiber 2, and to ensure that it always accurately covers the predetermined pile protection area, an adhesive tape connection structure 10 is provided between the PVC sleeve 7 and the main reinforcement 1. The adhesive tape connection structure 10 is located at both ends of the PVC sleeve 7.

[0027] The sonic logging tube 11 of this protection device is welded inside the reinforcing cage, and its height is not less than 0.5 meters higher than the design elevation of the pile body. The bottom and opening of the sonic logging tube 11 are sealed, and the sonic logging tube 11 can be used to detect the integrity of the pile body in the later stage using ultrasonic transmission method.

[0028] The inner diameter of the PVC sleeve 7 matches the size of the grating fiber 2. The number of grating fibers 2 in the protective device is 3, 6 or 15 bundles. The number of grating fibers on the mountain side is 15 bundles, and the number of grating fibers in the remaining areas is 3 or 6 bundles.

[0029] The operating procedure for this protection device is as follows:

[0030] 1. Preparation of the reinforcing cage: First, prepare the reinforcing cage for the anti-slide pile. The main reinforcement bars adopt a mechanical connection method that conforms to the specifications, with staggered joints to ensure that the number of joints in the same section does not exceed 50% of the total number of main reinforcement bars. The lap length of the stirrups 12 is set to 20 cm, and double-sided welding is performed on the lap section to ensure the overall rigidity and stability of the reinforcing cage.

[0031] 2. Pre-binding of grating optical fibers: Multiple bundles of grating optical fibers are pre-bound along the main reinforcement. Multiple grating sensors are arranged on the optical fibers at even intervals. Corrosion-resistant ropes are used to secure the fibers tightly near each sensor.

[0032] 3. Installation of Protective Sleeve: Install a PVC sleeve on the fiber optic segment corresponding to the designed pile-breaking area. The length of this sleeve should be at least twice the length of the entire pile-breaking area. For further enhanced protection, a thin-walled steel pipe can be nested inside the PVC sleeve. The length of this steel pipe extends from the estimated bottom of the pile-breaking area to above the top of that area.

[0033] 4. Leakage prevention treatment: Both ends of the PVC sleeve are kept open to allow the optical fiber to pass through. At each end, first fill and tighten it with asphalt-impregnated hemp fiber, and then wrap and seal the outside of the sleeve with multiple layers of waterproof tape.

[0034] 5. Fixing and auxiliary structure: At both ends of the PVC sleeve, use adhesive tape to stick and fix the PVC sleeve to the main reinforcement.

[0035] 6. Pile Construction and Demolition: After the reinforcement cage is lowered and the concrete is poured, curing is carried out. Once the strength is reached, the pile heads that exceed the design elevation are demolished.

[0036] 7. Subsequent Construction: After the pile breaking is completed, carefully remove the PVC sleeve and thin-walled steel pipe above the pile breaking area to expose the intact optical fiber grating. Construction personnel can then easily lead out the optical fiber and continue with the wiring, binding, and monitoring system connection work in the cap beam.

[0037] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any minor modifications, equivalent substitutions and improvements made to the above embodiments based on the technical essence of the present utility model should be included within the protection scope of the technical solution of the present utility model.

Claims

1. A grating fiber optic protection device for the pile head of a collapsed anti-slide pile, used to protect the grating fiber inside the pile head in the collapsed area, wherein the grating fiber is pre-tied to the main reinforcement of the anti-slide pile's steel cage, characterized in that: It also includes a PVC sleeve fitted over the grating optical fiber; a plurality of grating sensors are evenly spaced on the grating optical fiber, and rope binding points are set near the grating sensors; the length of the PVC sleeve extends at least twice the length of the pile breaking area from the bottom of the pile breaking area; after passing through the PVC sleeve, the grating optical fiber extends along the main reinforcement to the bottom of the pile.

2. The optical fiber grating protection device for the pile head of a ruptured sliding pile according to claim 1, characterized in that: A thin-walled steel pipe may be nested inside the PVC sleeve, the length of which extends from the bottom of the pile breaking area to above the pile breaking area.

3. The optical fiber grating protection device for the pile head of a sliding pile according to claim 2, characterized in that, The PVC sleeve is open at both ends, the inside of the PVC sleeve is filled with asphalt hemp fibers, and the outer side of the end of the PVC sleeve is wrapped with waterproof tape.

4. The optical fiber grating protection device for the pile head of a sliding pile according to claim 3, characterized in that, An adhesive tape connection structure is provided between the PVC sleeve and the main reinforcement, and the adhesive tape connection structure is located at both ends of the PVC sleeve.

5. The optical fiber grating protection device for the pile head of a sliding pile according to claim 1, characterized in that, It also includes a sonic logging pipe, which is welded inside the reinforcing cage and is at least 0.5 meters higher than the design elevation of the pile. The bottom and opening of the sonic logging pipe are both sealed.

6. The optical fiber grating protection device for the pile head of a sliding pile according to claim 1, characterized in that, The number of grating optical fibers is 3, 6, or 15.

7. The optical fiber grating protection device for the pile head of a sliding pile according to claim 1, characterized in that, The main reinforcement bars of the steel cage are mechanically connected, with staggered joints, and the number of joints in the same section does not exceed 50% of the total number of main reinforcement bars; the steel cage is also equipped with stirrups, the lap length of the stirrups is 20 cm, and the lap joints of the stirrups are welded on both sides.

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