Three-way joint meter based on fiber bragg grating sensing technology

Abstract

The invention belongs to the technical field of engineering geological disaster monitoring, and discloses a three-way joint meter based on a fiber grating sensing technology. The three-way joint meter is mainly composed of a bottom plate, a top cover, a moving piece, a positioning piece, an elastic material and a fiber bragg grating. Through an integrated fiber bragg grating sensing technology, the crack meter can accurately measure changes of cracks in three directions of opening and closing, shearing and settling. According to the design, the deformation characteristic of the elastic material is fully utilized, accurate displacement sensing of the moving part and the positioning part is combined, the accuracy and sensitivity of crack monitoring are remarkably improved, and the device is suitable for crack monitoring of various structures.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering geological disaster monitoring and relates to a three-way crack meter based on optical fiber grating sensing technology. Background Art

[0002] The peripheral joint is the joint between the concrete face plate and the toe plate, and is also the part of the concrete face rockfill dam that is very sensitive to deformation and prone to leakage. The deformation of the peripheral joint is an important basis for judging the safety of the water-stop structure between the concrete face plate and the toe plate, and plays a key role in the evaluation of the anti-seepage effect of the concrete face dam.

[0003] The deformation of the peripheral joints of concrete face rockfill dams is usually monitored by a three-dimensional joint meter. The sensitivity and measurement accuracy of the three-dimensional joint meter directly affect the accuracy of the calculation of the peripheral joint deformation. However, the three-dimensional joint meter in the prior art has problems such as complex structure, large measurement error, and susceptibility to reservoir water disturbance. Therefore, how to develop an efficient and accurate three-dimensional joint meter to ensure the safety of the structural form of the face rockfill dam has become an urgent issue to be solved. Summary of the invention

[0004] In view of the existing problems, the present invention provides a three-dimensional seam meter based on fiber grating sensing technology.

[0005] The technical solution of the present invention:

[0006] A three-dimensional crack meter based on fiber grating sensing technology includes a bottom plate, a top cover, a moving part, a positioning part, an elastic material and a fiber grating; by integrating the fiber grating sensing technology, the crack meter can accurately measure the changes of cracks in three directions. In terms of design, the deformation characteristics of elastic materials are used, combined with the precise displacement perception of the moving part and the positioning part, which significantly improves the accuracy and sensitivity of crack monitoring and is suitable for crack monitoring of various structures.

[0007] The bottom plate and the top cover together form a protective housing for the three-way crack meter, which is firmly mounted on one side of the crack and serves as a fixed reference point during the monitoring process;

[0008] The moving part comprises a moving part bottom plate, a moving part column and a hook, wherein the moving part column is fixed on the moving part bottom plate, and the hook is fixed on one end of the moving part bottom plate; the moving part bottom plate is fixed on the other side of the crack, and two elastic materials are fixed on the moving part column, and one elastic material is fixed on the moving part hook;

[0009] The function of the positioning member is to assist the moving member in completing the initial positioning, ensuring that the starting position of the moving member is consistent with the calibration state, thereby achieving accurate measurement of the crack development;

[0010] The elastic material has excellent elastic recovery characteristics, can be deformed rapidly at the moment of force, and immediately recover after the external force is removed, thus achieving instant response to deformation;

[0011] The fiber Bragg grating is a passive filter device with high sensitivity, high resolution and excellent anti-electromagnetic interference capability, and is suitable for monitoring multi-dimensional parameters such as deformation, stress and temperature of the structure;

[0012] Furthermore, the seam meter includes a bottom plate, a top cover, a moving part, a positioning part, an elastic material and a fiber grating. The bottom plate is fixed to one side of the crack, which not only protects the seam meter, but also serves as a fixed reference point in subsequent data processing; the top cover is used to protect the internal structure of the seam meter to avoid external interference during the measurement process; the moving part is installed on the other side of the crack and can move with the expansion of the crack, and the relative displacement between it and the bottom plate and the top cover directly reflects the dynamic development process of the crack; the positioning part is used to assist the moving part in initial positioning to ensure that its initial position information is accurate and reliable; the elastic material is used to accurately measure the relative displacement between the moving part and the bottom plate and the shell; the fiber grating is pasted on the elastic material to monitor its strain state in real time, thereby reflecting the dynamic changes of the crack with high precision.

[0013] Furthermore, the bottom plate is designed to be square and is provided with two non-overlapping columns for firmly fixing the elastic material, and a rectangular hole is opened in the center so that the column of the moving part can penetrate and limit its maximum displacement; the elastic material includes three, specifically two horizontal elastic materials and one vertical elastic material, wherein the two horizontal elastic materials respectively connect the column of the moving part and the two columns on the bottom plate, and the vertical elastic material connects the hook on the moving part and the top cover, and the three elastic materials are arranged in a non-collinear manner, and can respectively measure the relative displacement between the bottom plate and the moving part in three different directions, that is, along the length direction of the three elastic materials, the two horizontal elastic materials are connected at a common point on the moving part, and the vertical elastic material remains perpendicular to the plane where the two horizontal elastic materials are located; the fiber grating includes four optical fibers, three of which are strain optical fibers, which are precisely pasted on the three elastic materials for accurately measuring strain changes, and the other is a temperature optical fiber, which is pasted on the bottom plate for monitoring the temperature change of the seam meter and performing temperature compensation on the strain measurement results, thereby ensuring the accuracy and reliability of the measurement results.

[0014] Furthermore, the calculation of the three-dimensional seam meter based on fiber grating sensing technology includes the following steps:

[0015] S101, accurately measuring the central wavelengths of the strain optical fiber and the temperature optical fiber to obtain initial data.

[0016] S102, using the difference in the center wavelength of the strain optical fiber, the strain borne by the elastic material is calculated by the fiber grating strain theory method. At the same time, the center wavelength difference of the temperature optical fiber is used for temperature compensation to eliminate the influence of temperature change on the strain measurement result, thereby ensuring the accuracy of the measurement result.

[0017] S103, calculating the length change of the elastic material according to the strain value of the elastic material in combination with its material properties, thereby reflecting the displacement change of the crack in a specific direction.

[0018] S104, combining the initial fixed point O of the moving part and the point O' after moving as the crack develops, and according to the length change of the elastic material, the displacement change from point O to point O' is obtained.

[0019] Furthermore, in the three-dimensional seam meter based on fiber grating sensing technology, in S102, the strain calculation formula is as follows:

[0020]

[0021] Where ε is the strain of the elastic material, Δλ B1 and Δλ B2 are the center wavelength differences of strain fiber and temperature fiber, λ B1 and λ B2 are the initial center wavelengths of the strained fiber and the temperature fiber, respectively, e is the effective elastic-optical coefficient of the fiber Bragg grating.

[0022] Furthermore, in the three-dimensional seam meter based on fiber grating sensing technology, in S103, the length change calculation formula of the elastic material is as follows:

[0023] ΔL=εL

[0024] Where ΔL is the change in length of the elastic material, and L is the original length of the elastic material.

[0025] Furthermore, in the three-dimensional seam meter based on fiber grating sensing technology, in S104, the displacement change of the displacement member is calculated as follows:

[0026] In three-dimensional space, a column A on the bottom plate is selected as the origin of coordinates, the vertical crack length direction is the x-axis, the crack length direction, that is, the direction of the line connecting the two columns on the bottom plate is the y-axis, and the plane direction of the vertical crack is the z-axis. The x, y and z axis directions conform to the left-hand coordinate system; set points A, B, and C as fixed reference points, where AO and BO represent two horizontal elastic materials, and CO represents a vertical elastic material. When the crack does not expand, these elastic materials are in the initial state, with lengths of AO, BO and CO respectively.

[0027] When cracks develop, the elastic material will deform, but one end of it remains fixed at points A, B, and C, while the other end moves to a new position. In order to determine the spatial coordinates of point O' on the moving part, a spatial geometry method can be used. Specifically, three spheres are constructed with points A, B, and C as centers and AO', BO', and CO' as radii. These three spheres intersect at two points in space, one of which has a z value greater than 0 and the other less than 0. Since the moving part cannot pass through the bottom plate, that is, the z value cannot be greater than 0, the points with z values ​​greater than 0 are discarded, and the points with z values ​​less than 0 are retained, which are the required point O';

[0028] By solving the intersection of these three spheres, the spatial coordinates of point O' can be obtained (x2, y2, z2). At the same time, the spatial coordinates of point O (i.e., the initial fixed point of the moving part) are known to be (x1, y1, z1). Therefore, by calculating the spatial distance difference between point O and point O', the relative displacement of point O and point O' can be obtained, thereby reflecting the actual changes of the crack in three-dimensional space.

[0029] Furthermore, the three-way seam meter based on fiber grating sensing technology is characterized in that, in S104, the formula for obtaining the change in each direction is:

[0030] Change in opening and closing direction:

[0031] Δx=x2-x1

[0032] Shear direction variation:

[0033] Δy=y2-y1

[0034] Change in settlement direction:

[0035] Δz=z2-z1

[0036] Beneficial effects: The present invention discloses a three-dimensional crack meter based on fiber grating sensing technology. By integrating fiber grating sensing technology, the crack meter can accurately measure the changes of cracks in three directions. Its design utilizes the deformation characteristics of elastic materials and combines the precise displacement perception of moving parts and positioning parts, which significantly improves the accuracy and sensitivity of crack monitoring and is suitable for crack monitoring of various structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A monitoring flow chart of a three-way seam meter based on fiber grating sensing technology in an embodiment of the present invention;

[0038] Figure 2 Schematic diagram of the principle of a three-dimensional seam meter based on fiber Bragg grating sensing technology in an embodiment of the present invention; wherein (a) is before point O moves, and (b) is after point O moves;

[0039] Figure 3 Schematic diagram of the principle of calculation step S104 of the three-dimensional seam meter based on fiber grating sensing technology in an embodiment of the present invention;

[0040] Figure 4 Schematic diagram of the structure of a three-dimensional seam meter based on fiber grating sensing technology in an embodiment of the present invention.

[0041] In the figure: 1 bottom plate; 2 top cover; 3 moving part; 4 positioning part; 5 elastic material; 6 fiber grating. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the embodiment of the present invention clearer, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the scope of the present invention.

[0043] A three-dimensional crack meter based on fiber grating sensing technology, such as Figure 4 The figure includes a bottom plate, a top cover, a moving part, a positioning part, an elastic material and a fiber grating.

[0044] The bottom plate and the top cover together form the protective housing of the present invention, which is firmly mounted on one side of the crack and serves as a fixed reference point during the monitoring process;

[0045] The moving member comprises a moving member bottom plate, a moving member column and a hook, wherein the moving member column is fixed on the moving member bottom plate, and the hook is fixed on one end of the moving member bottom plate; the moving member bottom plate is fixed on the other side of the crack and moves with the expansion of the crack, and two elastic materials are fixed on the moving member column, and one elastic material is fixed on the moving member hook;

[0046] The main function of the positioning member is to assist the moving member in completing the initial positioning, ensuring that the starting position of the moving member is consistent with the calibration state, thereby achieving accurate measurement of the crack development;

[0047] The elastic material has excellent elastic recovery characteristics, can be deformed rapidly at the moment of force, and immediately recover after the external force is removed, thus achieving instant response to deformation;

[0048] The fiber Bragg grating is a passive filter device with high sensitivity, high resolution and excellent anti-electromagnetic interference ability, and is suitable for monitoring multi-dimensional parameters such as deformation, stress and temperature of the structure. The present invention monitors the length change of the elastic material through the fiber Bragg grating, and transmits the monitoring data to the spatial coordinate calculation module for processing. After calculation, the user can view the position change of the moving part relative to the bottom plate and the top cover in the output module, that is, the opening and closing, shearing and settlement of the crack. By integrating the fiber Bragg grating sensing technology, the crack meter can accurately measure the changes of the crack in three directions. The design utilizes the deformation characteristics of the elastic material and combines the precise displacement perception of the moving part and the positioning part to significantly improve the accuracy and sensitivity of crack monitoring, and is suitable for crack monitoring of various structures. The output module has its own crack development analysis strategy, which integrates the opening and closing, shearing and settlement of the crack to realize the intelligent monitoring of the safety situation and dynamic changes of the crack deformation. This strategy makes the evaluation results more accurate, and provides systematic, effective and intelligent monitoring for crack development, further promotes the group prevention and control of geological disasters, and enhances the public safety function of the city.

[0049] Working principle and technical details

[0050] In a specific embodiment, the three-dimensional joint meter based on fiber grating sensing technology comprises a bottom plate 1, a top cover 2, a moving part 3, a positioning part 4, an elastic material 5 and a fiber grating 6. The bottom plate 1 is fixed on one side of the crack to protect the joint meter and serve as a fixed reference point for subsequent data processing; the top cover 2 is used to protect the internal structure of the joint meter to avoid external interference during measurement; the moving part 3 is fixed on the other side of the crack and moves with the development of the crack, and its relative displacement with the bottom plate 1 and the top cover 2 reflects the actual development of the crack; the positioning part 4 is used to assist the moving part 3 in initial positioning to ensure that its initial position is accurate; the elastic material 5 is used to accurately measure the relative position change between the bottom plate 1 and the top cover 2 and the moving part 3; the fiber grating 6 is pasted on the elastic material 5 to monitor the strain state of the elastic material 5 in real time.

[0051] In a specific embodiment, the present invention discloses a three-dimensional seam meter based on fiber grating sensing technology, which comprises a bottom plate 1, a top cover 2, a moving part 3, a positioning part 4, an elastic material 5 and a fiber grating 6. Specifically, the base plate 1 is firmly installed on one side of the crack as a fixed reference point during the measurement process to ensure the stability and accuracy of the measurement data; the top cover 2 is designed to cover and protect the internal precision components of the crack meter, effectively isolating it from external interference or potential damage; the moving part 3 is fixed on the other side of the crack and moves accordingly as the crack expands, and the relative displacement between it and the base plate 1 and the top cover 2 directly reflects the actual development dynamics of the crack; the positioning part 4 is used to accurately set the position of the moving part 3 during the initial installation to ensure that the starting point of the measurement data is clear and traceable; the elastic material 5 is arranged between the moving part 3 and the base plate 1 and the top cover 2, and with its excellent deformation characteristics, it can sensitively capture and transmit the relative position changes between the three; the fiber grating 6 is pasted on the elastic material 5, and uses the high sensitivity of the fiber grating to deformation to monitor the strain in real time, thereby providing reliable data support for high-precision monitoring of the crack in the three dimensions of opening and closing, shearing and settlement.

[0052] In a specific embodiment, the bottom plate 1 is square and equipped with two non-overlapping columns for fixing the elastic material 5. A rectangular hole is opened in the center of the bottom plate 1 to allow the column on the moving part 3 to move freely therein, thereby realizing accurate monitoring of crack expansion; the elastic material 5 is composed of two horizontal elastic materials and one vertical elastic material, the two horizontal elastic materials respectively connect the column of the moving part 3 and the two columns on the bottom plate 1, and the vertical elastic material connects the hook on the moving part 3 and the top cover 2. These three elastic materials 5 are not collinear in spatial layout, and the relative displacements in three different directions, i.e., along the length direction of the three elastic materials, are measured respectively. In particular, the connection points of the two horizontal elastic materials on the moving part 3 coincide, while the vertical elastic material is perpendicular to the plane where the two horizontal elastic materials are located; the fiber gratings 6 are configured with four in total, three of which are strain optical fibers, which are pasted on the surface of the elastic material 5 to monitor its strain changes in real time; the other is a temperature optical fiber, which is pasted on the bottom plate 1 and is specifically used to measure the temperature change of the joint meter to eliminate the potential interference of the temperature effect on the strain measurement, thereby ensuring the accuracy and stability of the measurement results.

[0053] In a specific embodiment, the calculation includes the following steps

[0054] S101, accurately measuring the central wavelengths of the strain optical fiber and the temperature optical fiber to obtain initial data.

[0055] S102, using the central wavelength difference of the strain optical fiber and combining the fiber Bragg grating strain theory method to calculate the strain borne by the elastic material 5. At the same time, temperature compensation is performed through the central wavelength difference of the temperature optical fiber to eliminate the influence of temperature change on the strain measurement result and ensure the measurement accuracy.

[0056] S103, calculating the length change of the elastic material 5 according to the strain value of the elastic material 5 in combination with its material properties, thereby reflecting the displacement change of the crack in a specific direction.

[0057] S104, combining the initial fixed point O of the moving member 3 and the point O' after moving as the crack develops, and according to the length change of the elastic material 5, the displacement change from point O to point O' is obtained.

[0058] In a specific embodiment, in S102, the strain calculation formula is as follows:

[0059]

[0060] Where ε is the strain of the elastic material 5, Δλ B1 and Δλ B2 are the center wavelength differences of strain fiber and temperature fiber, λ B1 and λ B2 are the initial center wavelengths of the strained fiber and the temperature fiber, respectively, e is the effective elastic-optical coefficient of the fiber Bragg grating 6.

[0061] In a specific embodiment, in S103, the length change calculation formula of the elastic material 5 is as follows:

[0062] ΔL=εL

[0063] Wherein, ΔL is the length change of the elastic material 5 , and L is the original length of the elastic material 5 .

[0064] In a specific embodiment, in S104, the displacement change amount of the displacement member 3 is calculated as follows:

[0065] In three-dimensional space, a column A on the bottom plate 1 is selected as the origin of the coordinates, the vertical crack length direction is the x-axis, the crack length direction, i.e. the direction of the line connecting the two columns on the bottom plate 1, is the y-axis, and the plane direction of the vertical crack is the z-axis. The x, y and z-axis directions conform to the left-hand coordinate system; set points A, B, and C as fixed reference points, where AO and BO represent two horizontal elastic materials, and CO represents a vertical elastic material. When the crack does not expand, the elastic material 5 is in the initial state, with lengths of AO, BO and CO, respectively.

[0066] When the crack develops, the elastic material 5 will deform, but one end of it is still fixed at points A, B, and C, and the other end moves to a new position. In order to determine the spatial coordinates of point O' on the moving part 3, a spatial geometry method can be used. Specifically, three spheres are constructed with points A, B, and C as the center and AO', BO', and CO' as the radius. These three spheres intersect at two points in space, one of which has a z value greater than 0 and the other has a z value less than 0. Since the moving part cannot pass through the bottom plate, that is, the z value cannot be greater than 0, the point with a z value greater than 0 is discarded, and the point with a z value less than 0 is retained, which is the desired point O';

[0067] By solving the intersection of these three spheres, the spatial coordinates of point O' (x2, y2, z2) can be obtained. At the same time, the spatial coordinates of point O (i.e., the initial fixed point of the moving part 3) are known to be (x1, y1, z1). Therefore, by calculating the spatial distance difference between point O and point O', the relative displacement of point O and point O' can be obtained, thereby reflecting the actual change of the crack in three-dimensional space.

[0068] In a specific embodiment, in S104, the formula for obtaining the change in each direction is:

[0069] Change in opening and closing direction:

[0070] Δx=x2-x1

[0071] Shear direction variation:

[0072] Δy=y2-y1

[0073] Change in settlement direction:

[0074] Δz=z2-z1

[0075] In a specific embodiment, the computing system of the three-dimensional seam meter based on fiber grating sensing technology includes:

[0076] The measurement module is closely connected with the spatial coordinate calculation module. Its core components include fiber Bragg grating and fiber Bragg grating demodulator. The main function of this module is to measure and record the central wavelength change of fiber Bragg grating in real time and transmit the data to the spatial coordinate calculation module for processing. As a highly sensitive strain sensing element, the slight deviation of the central wavelength of fiber Bragg grating can accurately reflect the deformation state of elastic materials.

[0077] The spatial coordinate calculation module is connected to the measurement module and the output module. First, the spatial coordinate calculation module presets a three-dimensional coordinate system and receives the fiber Bragg grating center wavelength data provided by the measurement module. Through complex algorithms, these wavelength data are converted into strain and length changes, and finally into spatial coordinates in the preset coordinate system. This process converts the one-dimensional deformation of the elastic material into the three-dimensional spatial position of the measurement point.

[0078] The output module is connected to the spatial coordinate calculation module and is responsible for receiving and processing the spatial coordinate values ​​output by the spatial coordinate calculation module. Based on these coordinate values, the output module calculates the changes in the three directions of opening and closing, shearing and settlement of the cracks. These data are displayed in precise digital form, providing important support for structural health monitoring and geological disaster early warning.

[0079] In a specific embodiment, the computer device includes a memory and a processor, the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the calculation method of the three-dimensional seam meter based on fiber grating sensing technology.

[0080] In a specific embodiment, the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor executes the steps of the calculation method of a three-dimensional seam meter based on fiber grating sensing technology.

[0081] In a specific embodiment, the information data processing terminal is used to implement the computing system of the three-dimensional seam meter based on the fiber grating sensing technology.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the above embodiments have described the present invention in detail, those skilled in the art should understand that they can still modify the technical solutions described in the embodiments, or replace some or all of the technical features therein with equivalents. Such modifications or replacements do not change the essence of the corresponding technical solutions, nor do they exceed the protection scope of the embodiments of the present invention.

Claims

1. A three-dimensional seam meter based on fiber grating sensing technology, characterized in that: The three-dimensional seam meter comprises a bottom plate, a top cover, a moving part, a positioning part, an elastic material and a fiber grating; The bottom plate and the top cover together form a protective housing of the three-way crack meter, which is installed on one side of the crack and serves as a fixed reference point during the monitoring process; The moving member comprises a moving member bottom plate, a moving member column and a hook, wherein the moving member column is fixed on the moving member bottom plate, and the hook is fixed on one end of the moving member bottom plate; the moving member bottom plate is fixed on the other side of the crack, and moves with the expansion of the crack, and the relative displacement between the moving member bottom plate and the top cover directly reflects the dynamic development process of the crack; The positioning member assists the moving member in completing the initial positioning, ensuring that the starting position of the moving member is consistent with the calibration state, and realizing accurate measurement of the actual expansion of the crack; The elastic material can be deformed rapidly at the moment of being subjected to force, and recover immediately after the external force is removed, thereby achieving an instant response to the deformation; the elastic material is fixed between the moving part and the bottom plate and the top cover, and is used to measure the relative displacement between the moving part and the bottom plate and the top cover; The fiber grating is a passive filter component, which is pasted on the elastic material and is used to monitor its strain state in real time, thereby reflecting the dynamic changes of the crack.

2. The three-dimensional joint meter according to claim 1, characterized in that: The bottom plate is square and is provided with two non-overlapping columns for fixing the elastic material; a rectangular hole is provided on the bottom plate so that the column of the moving part can be inserted and its maximum displacement is limited; the elastic material includes three pieces, namely, two horizontal elastic materials and one vertical elastic material, wherein the two horizontal elastic materials respectively connect the column of the moving part and the two columns on the bottom plate, and the vertical elastic material connects the hook on the moving part and the top cover, and the three elastic materials are arranged in a non-collinear manner to respectively measure the relative displacement between the bottom plate and the moving part in three different directions, i.e., along the length direction of the three elastic materials, the two horizontal elastic materials are connected at a common point on the moving part, and the vertical elastic material is kept perpendicular to the plane where the two horizontal elastic materials are located; the fiber grating includes four optical fibers, three of which are strain optical fibers, which are correspondingly pasted on the three elastic materials and are used to measure the strain changes of the three elastic materials, and the other is a temperature optical fiber, which is pasted on the bottom plate and is used to monitor the temperature changes of the three-way joint meter and to perform temperature compensation on the strain measurement results.

3. The calculation method of the three-dimensional joint meter according to claim 2, characterized in that: The following steps are involved: S101, measures the central wavelengths of three strain optical fibers and one temperature optical fiber; S102, calculating the strain of the elastic material using the central wavelength difference of the strain optical fiber, and performing temperature compensation using the central wavelength difference of the temperature optical fiber; S103, calculating the length of the elastic material after the change; S104, obtaining the spatial coordinates of point O' and calculating the displacement change from point O to point O'; Among them, O' is the initial fixed point of the moving part, and O is the point after the moving part moves with the development of the crack.

4. The calculation method according to claim 3, characterized in that: In S102, the strain calculation formula is as follows: Where ε is the strain of the elastic material, Δλ B1 and Δλ B2 are the center wavelength differences of strain fiber and temperature fiber, λ B1 and λ B2 are the initial center wavelengths of the strained fiber and the temperature fiber, respectively, e is the effective elastic-optical coefficient of the fiber Bragg grating.

5. The calculation method according to claim 3, characterized in that: In S103, the length change calculation formula of the elastic material is as follows: ΔL=εL Where ΔL is the change in length of the elastic material, and L is the original length of the elastic material.

6. The calculation method according to claim 3, characterized in that: In S104, the displacement change of the displacement member is calculated as follows: In three-dimensional space, a column A on the bottom plate is selected as the origin of coordinates, the vertical crack length direction is the x-axis, the crack length direction, i.e. the direction of the line connecting the two columns on the bottom plate, is the y-axis, and the plane direction of the vertical crack is the z-axis. The x, y and z-axis directions conform to the left-hand coordinate system. Set points A, B and C as fixed reference points, where AO and BO represent two horizontal elastic materials, and CO represents a vertical elastic material. When the crack does not expand, the elastic material is in the initial state, and the lengths are AO, BO and CO respectively. When cracks develop, the elastic material will deform, but one end of it is still fixed at points A, B, and C, and the other end moves to a new position. In order to determine the spatial coordinates of point O' on the moving part, a spatial geometry method is used. Specifically, three spheres are constructed with points A, B, and C as centers and AO', BO', and CO' as radii. The three spheres intersect at two points in space, one of which has a z value greater than 0 and the other has a z value less than 0. Since the moving part cannot pass through the bottom plate, that is, the z value cannot be greater than 0, the point with a z value greater than 0 is discarded, and the point with a z value less than 0 is retained, which is the desired point O'. By solving the intersection of the three spheres, the spatial coordinates of point O' are obtained (x2, y2, z2); at the same time, it is known that the spatial coordinates of point O, which is the initial fixed point of the moving part, are (x1, y1, z1); therefore, by calculating the spatial distance difference between point O and point O', the relative displacement of point O and point O' is obtained.

7. The calculation method according to claim 3, characterized in that: In S104, the formula for the change in each direction is obtained as follows: Change in opening and closing direction: Δx=x2-x1 Shear direction variation: Δy=y2-y1 Change in settlement direction: Δz=z2-z1.

8. A computing system using the three-dimensional joint meter according to any one of claims 1 to 3, characterized in that: include: The measuring module is connected to the spatial coordinate calculating module and is used to input the measured central wavelength of the fiber grating into the spatial coordinate calculating module; The measurement module includes a fiber Bragg grating and a fiber Bragg grating demodulator; The spatial coordinate calculation module is connected to the measurement module and the output module, and is used to set the coordinate system and convert the fiber grating center wavelength input by the measurement module into strain and length change, and finally calculate the spatial position coordinates of the measurement point; The output module is connected with the spatial coordinate calculation module to calculate the changes in the opening and closing, shearing and settlement directions according to different spatial coordinates; Information data processing terminals are used to implement computing systems.

9. A computer device, characterized in that: The computer device includes a memory and a processor, the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the computing method according to any one of claims 3 to 7.

10. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by the processor, the processor executes the computing method according to any one of claims 3 to 7.

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