A shear sensor based on a weak grating array and a method of application thereof

Abstract

The application discloses a kind of shear sensor based on weak grating array and application method thereof, shear sensor includes shear detection unit, installation fixed unit, optical fiber protection unit, inside is equipped with a line groove for installing optical fiber lead wire, weak optical fiber grating sensor is installed in the line groove in shear detection unit, shear slot is set on shear detection unit, shear sensor is welded and fixed on steel sheet pile by installation fixed unit, it does not affect the overall structure stress characteristic of sheet pile, optical fiber protection unit is protected to optical fiber lead wire, avoid breaking in installation process, simultaneously conducive to reuse, reduce cost, when shear sensor is applied to the monitoring of steel sheet pile sinking installation state, shear sensor is installed on the lock of steel sheet pile, the current position of steel sheet pile lock is cut at shear slot by sinking, the change of optical fiber signal is monitored to monitor lock connection state, and the sinking position of steel sheet pile is confirmed.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering monitoring technology. More specifically, this invention relates to a shear sensor based on a weak grating array and its application method. Background Technology

[0002] In the construction of underwater bridge foundations, sheet piles are often used to build structures such as cofferdams. However, there is currently a lack of effective monitoring methods to ensure the firmness of the connection between adjacent sheet piles and the tightness of the interlocking. While electrical shear sensors are used abroad to detect the interlocking status of sheet piles, these sensors, based on electrical principles, are prone to damage during underwater construction, and are generally only deployable at a single point, making them non-reusable and costly.

[0003] In recent years, weak grating array fiber optic sensing technology has developed rapidly. It has the advantages of traditional fiber optic sensing technology, such as inherent safety, corrosion and high temperature resistance, flexible deployment and high measurement accuracy. At the same time, it also has the advantages of distributed fiber optic sensing technology, such as wide measurement range, simple system structure, easy deployment of single-cable structure and high spatial resolution. It has been widely used in various fields and has achieved good application results.

[0004] Currently, there is no mature solution that can effectively apply weak grating array fiber optic sensing technology to the detection of sheet pile interlocking connection status. Summary of the Invention

[0005] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0006] Another objective of this invention is to provide a shear sensor based on a weak grating array and its application method, in order to solve the technical problems of poor reusability and low detection accuracy of existing shear sensors used for monitoring the connection status of sheet pile interlocking.

[0007] To achieve these objectives and other advantages according to the present invention, a shear sensor based on a weak grating array is provided, comprising multiple shear sensors arranged vertically at intervals on a sheet pile locking device. Each shear sensor includes a shear detection unit, an installation and fixing unit, and an optical fiber protection unit arranged sequentially in a horizontal direction. The optical fiber protection unit has an optical fiber inlet and an optical fiber outlet at its two vertical ends. A groove is formed inside the shear detection unit, the installation and fixing unit, and the optical fiber protection unit. One end of the groove is connected to the optical fiber inlet, passes sequentially through the installation and fixing unit and the optical fiber protection unit, and the other end is connected to the optical fiber outlet. The weak fiber optic grating sensor is fixed in a groove located inside the shear detection unit. The fiber optic leads connected to both ends of the weak fiber optic grating sensor pass through the groove and exit the fiber optic inlet or outlet, respectively, and then connect to the transmission fiber optic cable. The transmission fiber optic cable is connected to an external signal demodulation device or light source. The shear detection unit, the mounting and fixing unit, and the fiber optic protection unit are all made of metal housing. The fiber optic leads are bonded to the inner wall of the groove. A pair of shear grooves are symmetrically opened vertically on the outer surface of the shear detection unit near the mounting and fixing unit. The mounting and fixing unit is used to pass through and fix the shear detection unit to the lock of the steel sheet pile, with the shear detection unit facing inward towards the lock.

[0008] Preferably, the structure is divided into a loading section and a covering section in the thickness direction. Part of the cable groove, the optical fiber inlet, and the optical fiber outlet are formed on the loading section, and another part is formed on the covering section. The loading section and the covering section are connected by bolts.

[0009] Preferably, the mounting and fixing unit has an overall T-shaped structure, with the smaller end being the head end and the larger end being the rear end. The shearing detection unit is connected to one side of the head end and is the same length as the head end, and the optical fiber protection unit is located on one side of the rear end and is the same length as the rear end.

[0010] This invention also provides an application method for a shear sensor based on a weak grating array, comprising the following steps:

[0011] S1: Assemble the shear sensor, and make vertically spaced slots on the latch according to the size of the shear detection unit, with the slots horizontally passing through the latch.

[0012] S2: Insert the shearing detection unit laterally into the buckle through the slot, and weld the mounting and fixing unit to the buckle;

[0013] S3: Between two adjacent shear sensors, the fiber outlet on the upper fiber protection unit and the fiber inlet on the lower fiber protection unit are connected by fusion splicing through a transmission fiber to form a shear sensor array, with the bottom one designated as the first shear sensor.

[0014] S4: Install distributed strain optical fibers, which are pasted from bottom to top on the surface of the installed steel sheet piles to detect strain.

[0015] S5: The transmission optical fiber led out from below the first shear sensor and the distributed strain optical fiber are fused together at the bottom of the steel sheet pile to form an integrated optical fiber monitoring system. Finally, the optical fiber monitoring system is connected to the signal demodulation equipment.

[0016] S6. Determine the precise location of the sheet pile sinking based on the monitored interlocking connection status. Use the position of all shear sensors as the primary scale. The disappearance of the signal from the weak fiber optic grating sensor within the current shear sensor indicates that the sheet pile has sunk to the current position. The distributed strain fiber attached to the surface of the sheet pile serves as the secondary scale to monitor strain and temperature changes. Based on the monitored stress and temperature change locations, determine the sinking position of the sheet pile interlocking between the two shear sensors, using this as the secondary scale, thereby achieving precise determination of the sheet pile interlocking sinking position.

[0017] Preferably, the assembly method of the shear sensor includes the following steps:

[0018] S11. Wipe and clean the wire groove, the optical fiber inlet, and the optical fiber outlet of the shear sensor with alcohol;

[0019] S12. Take the loading part, fix the weak fiber optic grating sensor in the groove corresponding to the shear detection unit, and put the other fiber optic leads into the grooves in the fiber optic protection unit and the mounting and fixing unit in sequence, and pre-fix them with quick-drying adhesive respectively.

[0020] S13. Apply epoxy resin adhesive evenly to the shear groove and wait for it to cure.

[0021] S14. Align the loading part of each shear sensor with the cover part and fix them with connecting bolts.

[0022] Preferably, the overall fiber optic monitoring system, while accurately determining the sinking position of the sheet piles, also provides cooling guidance for the water cooling system at abnormal temperature points, specifically including the following steps:

[0023] A1: Set the high temperature threshold T1, set the temperature change rate threshold △, and set the water-cooled low temperature threshold T2;

[0024] A2: The overall fiber optic monitoring system uses the same fiber optic cable to measure temperature and strain, and these fibers have the same strain coefficient R during calculation. ε and temperature coefficient R Τ Let λ be the wavelength change of the temperature-sensitive and strain-sensitive optical fibers when the sheet pile is driven to a certain position. T and λ εThe formulas for calculating temperature T and strain ε are as follows:

[0025]

[0026] The corresponding rate of temperature change v is calculated based on the temperature T obtained from the two calculations and the time interval between them.

[0027] A3: During the piling process, if the real-time temperature T of the steel sheet pile exceeds the high temperature threshold T1 according to the detection and calculation, the water cooling system will be activated to pour cooling water.

[0028] A4: Control the cooling water flow rate from large to small according to the temperature change rate v. When the temperature change rate v approaches the threshold Δ, immediately reduce the cooling water flow rate to prevent rapid cooling from causing deformation of the steel sheet pile.

[0029] A5: Stop pouring cooling water when the temperature T reaches the water-cooled low-temperature threshold T2.

[0030] The present invention has at least the following beneficial effects: The shear sensor based on a weak fiber grating array of the present invention includes a shear detection unit, an installation and fixing unit, and an optical fiber protection unit. A groove is provided in the shear detection unit, the installation and fixing unit, and the optical fiber protection unit for installing optical fiber leads. The weak fiber grating sensor is installed in the groove in the shear detection unit. The installation and fixing unit enables better welding and fixing of the shear sensor to the sheet pile. The optical fiber protection unit protects the connection path of the transmission optical fiber and the optical fiber leads, avoiding breakage during installation. It also facilitates reuse and reduces installation costs. The shear detection unit is provided with a shear groove, which facilitates shearing in the vertical direction during the sheet pile connection process. When the shear sensor is applied to the monitoring of the installation status of the sheet pile sinking, the shear sensor is installed on the locking buckle of the sheet pile, which does not affect the overall structural stress characteristics of the sheet pile. The sinking of the sheet pile shears the shear sensor at the shear groove at the current position. After shearing, the locking buckle connection status is monitored by monitoring the change of the optical fiber signal.

[0031] Other advantages, objectives and features of the present invention will be apparent in part from the following description, and in part from the understanding of those skilled in the art through study and practice of the invention. Attached Figure Description

[0032] Figure 1 This is a three-dimensional structural diagram of a single shear sensor of the present invention;

[0033] Figure 2 This is a cross-sectional view of a single shear sensor of the present invention;

[0034] Figure 3 This is a schematic diagram of the array of shear sensors of the present invention deployed at the locking point of a steel sheet pile;

[0035] Figure 4 This is a schematic diagram of the fiber optic strain / temperature sensing arrangement of the present invention.

[0036] The following are the reference numerals in the accompanying drawings: 1. Shear detection unit; 2. Installation and fixing unit; 3. Fiber optic protection unit; 4. Cable tray; 5. Shear groove; 6. Outer locking buckle of the installed sheet pile; 7. Locking buckle of the sheet pile to be installed; 8. Signal demodulation equipment; 9. Fiber optic lead; 10. Transmission fiber optic cable; 11. Distributed strain fiber optic cable; 12. Temperature fiber optic cable; 13. Strain fiber optic cable; 14. Shear sensor. Detailed Implementation

[0037] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0038] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified. In the description of this invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0039] like Figure 1-3 As shown, this invention provides a shear sensor based on a weak fiber grating array, comprising multiple shear sensors 14 arranged vertically at intervals on a steel sheet pile locking device. Each shear sensor 14 includes a shear detection unit 1, an installation and fixing unit 2, and an optical fiber protection unit 3 arranged sequentially in the horizontal direction. The optical fiber protection unit 3 has an optical fiber inlet and an optical fiber outlet at its two vertical ends. A groove 4 is formed inside the shear detection unit 1, the installation and fixing unit 2, and the optical fiber protection unit 3. One end of the groove 4 is connected to the optical fiber inlet, passes through the installation and fixing unit 2 and the optical fiber protection unit 3 in sequence, and the other end is connected to the optical fiber outlet. The weak fiber grating transmits... The sensor is fixed on the groove 4 inside the shear detection unit 1. The fiber optic leads 9 connected to both ends of the weak fiber optic grating sensor pass through the groove 4 and exit through the fiber optic inlet or outlet, respectively, and then connect to the transmission fiber 10. The transmission fiber 10 is connected to the external signal demodulation device 8 or the light source. The shear detection unit 1, the mounting and fixing unit 2, and the fiber optic protection unit 3 are all made of metal housing. The fiber optic leads 9 are bonded to the inner wall of the groove 4. A pair of shear grooves 5 are symmetrically opened on the outer surface of the shear detection unit 1 near the mounting and fixing unit 2. The mounting and fixing unit 2 is used to pass through and fix the shear detection unit 1 to the lock of the steel sheet pile, and the shear detection unit 1 is set facing the inside of the lock.

[0040] Sheet piles are generally installed by sequential driving. Locking structures are installed on both sides of the sheet pile. The locking 7 of the driven sheet pile to be installed is inserted into the outer locking 6 of the already installed sheet pile. For ease of explanation, (The text continues with further details about sheet pile installation.) Figure 3 The left and right directions are horizontal, with Figure 3 The vertical direction is defined by the shear sensor 14. The overall structure comprises three parts: a shear detection unit 1, a mounting and fixing unit 2, and an optical fiber protection unit 3. The mounting and fixing unit 2 ensures better welding and fixing of the shear sensor 14 to the steel sheet pile. The optical fiber protection unit 3 protects the optical fiber lead 9 and its connection path to the transmission optical fiber 10, preventing breakage during installation. This also facilitates multi-sensor array reuse, reducing installation costs. A cable groove 4 is provided across the shear detection unit 1, mounting and fixing unit 2, and optical fiber protection unit 3 for installing the optical fiber lead 9. The cable groove 4 extends from one end of the optical fiber protection unit 3 where the optical fiber inlet is located, passes through the mounting and fixing unit 2 and the shear detection unit 1, and a weak fiber Bragg grating is installed within the shear detection unit 1. The sensor extends from the shear detection unit 1 towards the optical fiber outlet and connects to the other end of the cable tray. It also passes through the installation and fixing unit 2 and the optical fiber protection unit 3 in sequence. The weak fiber grating sensor and the optical fiber lead 9 are glued to the metal shell of the cable tray 4. Shearing grooves 5 are symmetrically arranged on the outside of the shear detection unit 1. The shear sensor 14 is vertically arranged on the buckle. During the connection of the sheet pile through the buckle, it is sheared from the shearing groove 5. At this time, the weak grating signal detection unit will sense the disappearance of the grating reflection peak, thereby realizing the detection of the connection status of the sheet pile buckle and obtaining the position information of the steel sheet pile sinking. The structural design of the entire shear sensor 14 realizes a good connection between the sensor and the sheet pile, while not affecting the overall structural stress characteristics of the sheet pile, and is easy to shear during the connection of the sheet pile.

[0041] In another technical solution, such as Figure 1-2 As shown, the structure is divided into a loading section and a covering section in the thickness direction. A portion of the cable groove 4, the optical fiber inlet, and the optical fiber outlet are located on the loading section, and another portion is located on the covering section. The loading section and the covering section are connected by bolts. The shear sensor 14 is configured as two spliced ​​parts to facilitate the installation of the internal weak fiber Bragg grating sensor and the optical fiber lead 9.

[0042] In another technical solution, such as Figure 1-3As shown, the mounting and fixing unit 2 has an overall T-shaped structure, with the smaller end being the head end and the larger end being the rear end. The shear detection unit 1 is connected to one side of the head end and is the same length as the head end, while the fiber optic protection unit 3 is located on one side of the rear end and is the same length as the rear end. The mounting and fixing unit 2 is used for fixed connection with the locking buckle. By setting the mounting and fixing unit 2 to an L-shape, holes are drilled in the outer locking buckle 6 of the steel sheet pile. After the shear detection unit 1 passes through the hole, the rear end of the mounting and fixing unit 2 facing the shear detection unit 1 abuts against the vertical surface of the outer locking buckle 6 of the installed steel sheet pile, increasing the contact area between the mounting and fixing unit 2 and the locking buckle for easy welding and fixing.

[0043] This invention also provides an application method for a shear sensor based on a weak grating array, combined with... Figure 1-4 As shown, it includes the following steps:

[0044] S1: Assemble the shear sensor 14, and make slots on the latch at vertical intervals according to the size of the shear detection unit 1, with the slots horizontally passing through the latch.

[0045] S2: The shear detection unit 1 is inserted laterally into the latch through the slot, and the mounting and fixing unit 2 is welded to the latch. The vertical length of the shear detection unit 1 is not greater than the length of the mounting and fixing unit 2, so that the shear detection unit 1 can pass smoothly through the slot. The mounting and fixing unit 2 matches the size of the slot and is then welded, thereby fixing the shear sensor 14 to the latch. The fiber optic protection unit 3 is located outside the latches of the sheet piles on both sides to avoid affecting the downward movement of the sheet piles. The fiber optic protection unit 3 is used to provide protection for the routing path of the transmission fiber optic 10 and the fiber optic lead 9, and can smoothly transition to the connection with the weak fiber optic grating sensor with a certain curve.

[0046] S3: Between two adjacent shear sensors 14, the optical fiber outlet on the upper optical fiber protection unit 3 and the optical fiber inlet on the lower optical fiber protection unit 3 are connected by fusion splicing through transmission optical fiber 10 to form an array of shear sensors 14, with the bottom one designated as the first shear sensor 14. All shear sensors 14 are connected through transmission optical fiber 10 to form a signal path, constituting a shear sensor 14 monitoring array.

[0047] S4: Install distributed strain optical fibers 11, which are attached from bottom to top to the surface of the installed steel sheet piles for strain detection. The distributed strain optical fibers 11 are used to simultaneously measure strain and temperature changes.

[0048] S5: The transmission optical fiber 10 extending from below the first shear sensor 14 and the distributed strain optical fiber 11 are fused together at the bottom of the sheet pile to form an integrated optical fiber monitoring system. Finally, the optical fiber monitoring system is connected to the signal demodulation device 8. An optical fiber protection unit 3 can also be installed at the bottom along the connection path between the transmission optical fiber 10 and the first shear sensor 14 to provide structural protection for the transmission optical fiber 10.

[0049] S6. Determine the precise location of the sheet pile sinking based on the monitored interlocking connection status. Use the position of all shear sensors 14 as the primary scale. The disappearance of the signal from the weak fiber optic grating sensor in the current shear sensor 14 indicates that the sheet pile has sunk to the current position. The distributed strain fiber 11 attached to the surface of the sheet pile serves as the secondary scale to monitor strain and temperature changes. Based on the monitored stress and temperature change positions, determine the sinking position of the sheet pile interlocking between the two shear sensors 14 as the secondary scale, thereby achieving accurate determination of the sheet pile interlocking sinking position.

[0050] The shear sensor 14 is easy to set up for multi-sensor array reuse, with low single-point cost and simple installation. When adjacent sheet piles are interlocked, stress and temperature changes will occur. By using the signal corresponding to the shear sensor 14 as the main scale to determine the sinking position of the sheet pile, and combining it with the interval set by the shear sensor 14, the height range of the current sinking position of the sheet pile can be determined. At the same time, combined with the monitoring of strain and temperature changes within the current height on the distributed strain fiber optic cable 11 as a secondary scale, the sinking position of the sheet pile interlock can be determined more accurately, realizing array-type detection of the interlock connection status of the sheet pile and precise positioning of the sinking position.

[0051] In another technical solution, the assembly method of the shear sensor 14 includes the following steps:

[0052] S11. Wipe and clean the groove 4, the optical fiber inlet, and the optical fiber outlet of the shear sensor 14 with alcohol;

[0053] S12. Take the loading part and fix the weak fiber optic grating sensor in the groove 4 corresponding to the shear detection unit 1. The other fiber optic leads 9 are placed in the groove 4 in the fiber optic protection unit 3 and the mounting and fixing unit 2 respectively, and pre-fixed with quick-drying adhesive.

[0054] S13. Apply epoxy resin adhesive evenly to the shear groove 5 and wait for it to cure.

[0055] S14. Align the loading portion of each shear sensor 14 with the cover portion and secure them with connecting bolts.

[0056] The method of mounting the shear sensor 14 with optical fiber and weak grating optical fiber sensor in this embodiment is simple to operate, easy to mass-produce, and low in cost.

[0057] In another technical solution, the overall fiber optic monitoring system, while accurately determining the sinking position of the sheet piles, also provides cooling guidance for the water cooling system at abnormal temperature points, specifically including the following steps:

[0058] A1: Set the high temperature threshold T1, set the temperature change rate threshold △, and set the water-cooled low temperature threshold T2;

[0059] A2: The overall fiber optic monitoring system uses the same fiber optic cable to measure temperature and strain, and these fibers have the same strain coefficient R during calculation. ε and temperature coefficient R Τ Let λ be the wavelength change of the steel sheet pile at a certain position due to temperature change in optical fiber 12 and strain optical fiber 13. T and λ ε The formulas for calculating temperature T and strain ε are as follows:

[0060]

[0061] The corresponding rate of temperature change v is calculated based on the temperature T obtained from the two calculations and the time interval between them.

[0062] A3: During the piling process, if the real-time temperature T of the steel sheet pile exceeds the high temperature threshold T1 according to the detection and calculation, the water cooling system will be activated to pour cooling water.

[0063] A4: Control the cooling water flow rate from large to small according to the temperature change rate v. When the temperature change rate v approaches the threshold Δ, immediately reduce the cooling water flow rate to prevent rapid cooling from causing deformation of the steel sheet pile.

[0064] A5: Stop pouring cooling water when the temperature T reaches the water-cooled low-temperature threshold T2.

[0065] Because the optical fibers are in the same cable, the temperature values ​​measured in the temperature fiber and the strain fiber are the same, both being T. The strain and the change in current temperature are calculated by the change in wavelength. The change in temperature can guide the start-up and cooling duration of the water cooling system. The flow rate of the cooling water in the water cooling system is controlled according to the rate of temperature change v and the threshold Δ. At the same time, combined with the calculated strain, the deformation of the steel sheet piles during the cooling process of the water cooling system can be monitored to ensure that the strain is within a safe range during the cooling process. If it exceeds the safe range, the cooling water pouring is stopped immediately. Through the above steps, the piling efficiency can be improved, pile deformation can be avoided, and cooling water usage can be saved.

[0066] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. An application method for a shear sensor based on a weak grating array, characterized in that, Includes the following steps: S1: Assemble the shear sensor. The shear sensor includes multiple shear sensors arranged vertically at intervals on the steel sheet pile lock. Each shear sensor includes a shear detection unit, an installation and fixing unit, and an optical fiber protection unit arranged sequentially in the horizontal direction. The optical fiber protection unit has an optical fiber inlet and an optical fiber outlet at both ends vertically. The shear detection unit, the installation and fixing unit, and the optical fiber protection unit have a common groove. One end of the groove is connected to the optical fiber inlet, passes through the installation and fixing unit and the optical fiber protection unit in sequence, and the other end is connected to the optical fiber outlet. The weak fiber grating sensor is fixed on the groove located in the shear detection unit. The optical fiber leads connected to both ends of the weak fiber grating sensor pass through the groove and exit the optical fiber inlet or optical fiber outlet to connect to the transmission optical fiber. The transmission optical fiber is connected to an external signal demodulation device or light source. The shear detection unit, the installation and fixing unit, and the optical fiber protection unit are all made of metal shell material. The optical fiber leads are bonded to the inner wall of the groove. A pair of shear grooves are symmetrically opened vertically on the outer surface of the shear detection unit near the installation and fixing unit. The installation and fixing unit is used to pass through and fix on the lock of the steel sheet pile, and the shear detection unit is set facing inward of the lock. Slots are made vertically at intervals on the latch according to the size of the shear detection unit, and the slots are horizontally connected to the latch. S2: Insert the shearing detection unit laterally into the buckle through the slot, and weld the mounting and fixing unit to the buckle; S3: Between two adjacent shear sensors, the fiber outlet on the upper fiber protection unit and the fiber inlet on the lower fiber protection unit are connected by fusion splicing through a transmission fiber to form a shear sensor array, with the bottom one designated as the first shear sensor. S4: Install distributed strain optical fibers, which are pasted from bottom to top on the surface of the installed steel sheet piles to detect strain. S5: The transmission optical fiber led out from below the first shear sensor and the distributed strain optical fiber are fused together at the bottom of the steel sheet pile to form an integrated optical fiber monitoring system. Finally, the optical fiber monitoring system is connected to the signal demodulation equipment. S6. Determine the precise location of the sheet pile sinking based on the monitored interlocking connection status. Use the position of all shear sensors as the primary scale. The disappearance of the signal from the weak fiber optic grating sensor within the current shear sensor indicates that the sheet pile has sunk to the current position. The distributed strain fiber attached to the surface of the sheet pile serves as the secondary scale to monitor strain and temperature changes. Based on the monitored stress and temperature change locations, determine the sinking position of the sheet pile interlocking between the two shear sensors, using this as the secondary scale, thereby achieving precise determination of the sheet pile interlocking sinking position.

2. The application method of the shear sensor based on a weak grating array as described in claim 1, characterized in that, The shear sensor is divided into a loading part and a covering part in the thickness direction. A portion of the wire groove, the optical fiber inlet, and the optical fiber outlet are formed on the loading part, and another portion is formed on the covering part. The loading part and the covering part are connected by bolts.

3. The application method of the shear sensor based on a weak grating array as described in claim 1, characterized in that, The installation and fixing unit has an overall T-shaped structure, with the smaller end being the head end and the larger end being the rear end. The shearing detection unit is connected to one side of the head end and is the same length as the head end, and the optical fiber protection unit is located on one side of the rear end and is the same length as the rear end.

4. The application method of the shear sensor based on a weak grating array as described in claim 2, characterized in that, The assembly method of the shear sensor includes the following steps: S11. Wipe and clean the wire groove, the optical fiber inlet, and the optical fiber outlet of the shear sensor with alcohol; S12. Take the loading part, fix the weak fiber optic grating sensor in the groove corresponding to the shear detection unit, and put the other fiber optic leads into the grooves in the fiber optic protection unit and the mounting and fixing unit in sequence, and pre-fix them with quick-drying adhesive respectively. S13. Apply epoxy resin adhesive evenly to the shear groove and wait for it to cure. S14. Align the loading part of each shear sensor with the cover part and fix them with connecting bolts.

5. The application method of the shear sensor based on a weak grating array as described in claim 1, characterized in that, The overall fiber optic monitoring system, while accurately determining the sinking position of the sheet piles, also provides cooling guidance for the water cooling system at abnormal temperature points. Specifically, it includes the following steps: A1: Set the high temperature threshold T1, set the temperature change rate threshold △, and set the water-cooled low temperature threshold T2; A2: The overall fiber optic monitoring system uses the same fiber optic cable to measure temperature and strain, and these fibers have the same strain coefficient R during calculation. ε and temperature coefficient R Τ Let λ be the wavelength change of the temperature-sensitive and strain-sensitive optical fibers when the sheet pile is driven to a certain position. T and λ ε The formulas for calculating temperature T and strain ε are as follows: ， The corresponding rate of temperature change v is calculated based on the temperature T obtained from the two calculations and the time interval between them. A3: During the piling process, if the real-time temperature T of the steel sheet pile exceeds the high temperature threshold T1 according to the detection and calculation, the water cooling system will be activated to pour cooling water. A4: Control the cooling water flow rate from large to small according to the temperature change rate v. When the temperature change rate v approaches the threshold Δ, immediately reduce the cooling water flow rate to prevent rapid cooling from causing deformation of the steel sheet pile. A5: Stop pouring cooling water when the temperature T reaches the water-cooled low-temperature threshold T2.

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