Three-way joint meter based on fiber grating sensing technology

Abstract

The application belongs to the technical field of engineering geological disaster monitoring, and discloses a three-way joint meter based on fiber grating sensing technology.The three-way joint meter is mainly composed of 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 joint meter can accurately measure the changes of the crack in the opening, shearing and settlement directions.The design fully utilizes the deformation characteristics of the elastic material, combines the accurate displacement sensing of the moving part and the positioning part, significantly improves the accuracy and sensitivity of the crack monitoring, and is suitable for crack monitoring of various structures.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of engineering geological disaster monitoring, and relates to a three-way joint meter based on fiber grating sensing technology. BACKGROUND

[0002] The peripheral joint is the joint between the concrete panel and the toe plate, and is also a very sensitive and easily leaking part of the concrete panel rock-fill dam deformation. The size of the peripheral joint deformation is an important basis for judging the safety of the water stop structure between the concrete panel and the toe plate, and plays a key role in the evaluation of the impermeability effect of the concrete panel dam.

[0003] The deformation of the peripheral joint of the concrete panel rock-fill dam is usually monitored by a three-way joint meter. The sensitivity and measurement accuracy of the three-way joint meter directly affect the accuracy of the peripheral joint deformation calculation. However, the three-way joint meter in the prior art has problems such as complex structure, large measurement error, and easy disturbance by reservoir water. Therefore, how to develop an efficient and accurate three-way joint meter to ensure the safety of the structure form of the panel rock-fill dam has become an urgent issue to be solved. SUMMARY

[0004] In view of the existing problems, the present application provides a three-way joint meter based on fiber grating sensing technology.

[0005] The technical scheme of the present application is as follows:

[0006] A three-way joint meter based on fiber grating sensing technology, comprising a bottom plate, a top cover, a moving part, a positioning part, an elastic material and a fiber grating; by integrating fiber grating sensing technology, the joint meter can accurately measure the changes of the crack in three directions. In design, the deformation characteristics of the elastic material are utilized, combined with the accurate displacement sensing of the moving part and the positioning part, to significantly improve the accuracy and sensitivity of crack monitoring, which is suitable for various structural crack monitoring.

[0007] The bottom plate and the top cover together constitute the protective shell of the three-way joint meter, which is stably installed on one side of the crack as a fixed reference point during the monitoring process;

[0008] The moving part includes a moving part bottom plate, a moving part column and a hook, 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 positioning part is used to assist the moving part to complete the initial positioning, to ensure that the starting position of the moving part is consistent with the calibration state, so as to realize accurate measurement of the crack development;

[0010] The elastic material has excellent elastic recovery characteristics, can rapidly deform at the moment of force, and immediately recover after the external force is removed, thereby realizing instant response to deformation.

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

[0012] Further, the joint meter comprises 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 joint 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 joint meter and avoid external interference during measurement. The moving part is installed on the other side of the crack and can move with the expansion of the crack. The relative displacement between the moving part 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 initial positioning of the moving part to ensure the accuracy and reliability of the initial position information. 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 attached to the elastic material to monitor the strain state in real time, thereby accurately reflecting the dynamic changes of the crack.

[0013] Further, the bottom plate is designed as a square and is provided with two non-coincident columns for stably fixing the elastic material. A rectangular hole is formed in the center of the bottom plate, so that the column of the moving part can pass through and limit the maximum displacement. The elastic material includes three parts, specifically two horizontal elastic materials and one vertical elastic material. The two horizontal elastic materials are connected to the columns of the moving part and the two columns on the bottom plate, respectively. The vertical elastic material is connected to the hook on the moving part and the top cover. The three elastic materials are arranged in a non-collinear manner to measure the relative displacement of 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 perpendicular to the plane in which the two horizontal elastic materials are located. The fiber grating includes four optical fibers, three of which are strain optical fibers accurately attached to the three elastic materials for precise strain measurement, and the other one is a temperature optical fiber attached to the bottom plate for monitoring the temperature change of the joint meter and temperature compensation of the strain measurement result, thereby ensuring the accuracy and reliability of the measurement result.

[0014] Further, the calculation of the three-way joint meter based on the fiber grating sensing technology comprises the following steps:

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

[0016] S102, the strain of the elastic material is calculated by the strain theory of the fiber grating using the central wavelength difference of the strain fiber. Meanwhile, the temperature compensation is performed using the central wavelength difference of the temperature fiber to eliminate the influence of temperature change on the strain measurement result, ensuring the accuracy of the measurement result.

[0017] S103, the length change of the elastic material is calculated according to the strain value of the elastic material and the material characteristics, so as to reflect the displacement change of the crack in a specific direction.

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

[0019] Further, the three-way joint meter based on the fiber grating sensing technology in S102 has the following strain calculation formula:

[0020]

[0021] In the formula, ε is the strain of the elastic material, Δλ B1 and Δλ B2 are the central wavelength differences of the strain fiber and the temperature fiber respectively, λ B1 and λ B2 are the initial central wavelengths of the strain fiber and the temperature fiber respectively, P e is the effective photoelastic coefficient of the fiber grating.

[0022] Further, the three-way joint meter based on the fiber grating sensing technology in S103 has the following length change calculation formula of the elastic material:

[0023] ΔL = εL

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

[0025] Further, the three-way joint meter based on the fiber grating sensing technology in S104 has the following displacement change calculation method of the displacement part:

[0026] In the three-dimensional space, a column A on the base plate is selected as the coordinate origin, the vertical crack length direction is selected as the x-axis, the crack length direction is selected as the y-axis, and the vertical crack plane direction is selected as the z-axis. The x, y and z axis directions conform to the left-handed coordinate system. Points A, B and C are set as fixed reference points, wherein AO and BO represent two horizontal elastic materials respectively, and CO represents a vertical elastic material. When the crack is not expanded, these elastic materials are in the initial state, and the lengths are AO, BO and CO respectively.

[0027] When the crack develops, the elastic material will deform, but one end is still fixed at points A, B, C, and the other end moves to a new position. In order to determine the spatial coordinates of the point O' on the moving part, a spatial geometry method can be used. Specifically, three spherical surfaces are constructed with A, B, C as the center and AO', BO', CO' as the radius. The three spherical surfaces 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, the z value cannot be greater than 0, so the point with z value greater than 0 is discarded, and the point with z value less than 0 is retained, which is the point O' sought;

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

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

[0030] The opening and closing direction change amount is:

[0031] Δx=x2-x1

[0032] The shear direction change amount is:

[0033] Δy=y2-y1

[0034] The settlement direction change amount is:

[0035] Δz=z2-z1

[0036] Beneficial effects: the application discloses a three-way joint meter based on optical fiber grating sensing technology. By integrating optical fiber grating sensing technology, the joint meter can accurately measure the change of the crack in three directions. The design utilizes the deformation characteristics of elastic materials and combines the accurate displacement sensing of the moving part and the positioning part, significantly improving the accuracy and sensitivity of crack monitoring, and is suitable for various structural crack monitoring. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The three-way joint meter based on optical fiber grating sensing technology in the embodiment of the application is a monitoring flowchart;

[0038] Figure 2 The three-way joint meter based on optical fiber grating sensing technology in the embodiment of the application is a principle schematic diagram; wherein, (a) point O moves before, (b) is point O moves after;

[0039] Figure 3 It is a schematic diagram of the calculation principle of the three-way joint meter based on the fiber grating sensing technology in the embodiment of the application;

[0040] Figure 4 It is a structural schematic diagram of the three-way joint meter based on the fiber grating sensing technology in the embodiment of the application.

[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 application clearer, the technical scheme in the embodiment of the application will be clearly and completely described below in combination with the drawings in the embodiment of the application. Obviously, the described embodiment is only a part of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application. It should be understood that the specific embodiments described herein are only used to explain the application, and are not used to limit the scope of the application.

[0043] A three-way joint meter based on fiber grating sensing technology, as shown in Figure 4 It 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 jointly constitute the protective shell of the application, which is stably installed on one side of the crack as a fixed reference point in the monitoring process;

[0045] The moving part includes a moving part bottom plate, a moving part stand and a hook, the moving part stand 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, moves with the expansion of the crack, and fixes two elastic materials on the moving part stand and one elastic material on the moving part hook;

[0046] The main function of the positioning part is to assist the moving part to complete the initial positioning, to ensure that the starting position of the moving part is consistent with the calibration state, so as to realize the accurate measurement of the crack development;

[0047] The elastic material has excellent elastic recovery characteristics, can rapidly deform in the instant of force and immediately recover after the external force is removed, and realizes the immediate response to deformation;

[0048] The fiber grating is a passive filter device with high sensitivity, high resolution and excellent anti-electromagnetic interference capability, and is suitable for monitoring the deformation, stress and temperature of a structure and the like multidimensional parameters. The length change of the elastic material is monitored by the fiber grating, and the monitoring data are transmitted to a spatial coordinate calculation module for processing, and 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 grating sensing technology, the joint meter can accurately measure the change of the crack in three directions. The design utilizes the deformation characteristics of the elastic material, and combines the accurate displacement sensing of the moving part and the positioning part, significantly improves the accuracy and sensitivity of crack monitoring, and is suitable for various structure crack monitoring. The output module has a crack development analysis strategy, comprehensively analyzes the opening and closing, shearing and settlement of the crack, realizes the intelligent monitoring of the safety situation and dynamic change of the crack deformation, and the strategy makes the evaluation result more accurate, and provides systematic, effective and intelligent monitoring for the crack development, further promotes the group prevention and control of geological disasters, and enhances the urban public safety function.

[0049] Working principle and technical details

[0050] In specific embodiments, the three-way joint meter based on the 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, used for protecting the joint meter and serving as a fixed reference point, facilitating subsequent data processing; the top cover 2 is used for protecting the internal structure of the joint meter, avoiding 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 the relative displacement of the moving part 3 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, ensuring that the initial position is accurately known; 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, used for real-time monitoring of the strain state of the elastic material 5.

[0051] In specific embodiments, the disclosed three-dimensional joint movement measuring device based on fiber grating sensing technology comprises a base 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 joint, serving as a fixed reference point during measurement 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 measuring device, effectively isolating external interference or potential damage; the moving part 3 is fixed to the other side of the joint and moves accordingly as the joint expands, and the relative displacement between the moving part 3 and the base plate 1 and the top cover 2 directly reflects the actual development of the joint; the positioning part 4 is used to accurately set the position of the moving part 3 during initial installation, ensuring 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, which can sensitively capture and transmit the relative position changes between the three parts due to its excellent deformation characteristics; the fiber grating 6 is attached to the elastic material 5, which can monitor the strain in real time by utilizing the high sensitivity of the fiber grating to deformation, thereby providing reliable data support for high-precision monitoring of the joint in opening, shearing, and settlement.

[0052] In specific embodiments, the base plate 1 is square-shaped and equipped with two non-coincident vertical columns for fixing the elastic material 5, and a rectangular hole is formed in the center of the base plate 1 to allow the vertical columns on the moving part 3 to move freely, thereby achieving accurate monitoring of the joint expansion; the elastic material 5 is composed of two horizontal elastic materials and a vertical elastic material, with the two horizontal elastic materials connected to the vertical columns on the moving part 3 and the base plate 1, and the vertical elastic material connected to the hook on the moving part 3 and the top cover 2. The three elastic materials 5 are not collinear in spatial layout and measure the relative displacement in three different directions along the length of the elastic materials. 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 in which the two horizontal elastic materials lie; the fiber grating 6 is configured with four fibers, three of which are strain fibers attached to the surface of the elastic material 5 for real-time monitoring of strain changes, and the other is a temperature fiber attached to the base plate 1, which is specifically used to measure the temperature change of the measuring device to eliminate the potential interference of temperature effects on strain measurement, thereby ensuring the accuracy and stability of the measurement results.

[0053] In specific embodiments, the calculation includes the following steps

[0054] S101, accurately measuring the center wavelength of the strain fiber and the temperature fiber to obtain initial data.

[0055] S102, the strain of the elastic material 5 is calculated by using the center wavelength difference of the strain fiber and combining the strain theory of the fiber grating. Meanwhile, the temperature compensation is performed by using the center wavelength difference of the temperature fiber, so as to eliminate the influence of the temperature change on the strain measurement result and ensure the measurement accuracy.

[0056] S103, the length change amount of the elastic material 5 is calculated according to the strain value of the elastic material 5 and the material characteristics of the elastic material 5, so as to reflect the displacement change of the crack in a specific direction.

[0057] S104, the displacement change amount of the point O to the point O' is obtained according to the length change amount of the elastic material 5, in combination with the initial fixed point O of the moving part 3 and the point O' after the crack development.

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

[0059]

[0060] In the formula, ε is the strain of the elastic material 5, Δλ B1 and Δλ B2 are the center wavelength differences of the strain fiber and the temperature fiber respectively, λ B1 and λ B2 are the initial center wavelengths of the strain fiber and the temperature fiber respectively, P e is the effective photoelastic coefficient of the fiber grating 6.

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

[0062] ΔL=εL

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

[0064] In specific embodiments, in S104, the displacement change amount of the displacement part 3 is calculated as follows:

[0065] In the three-dimensional space, one column A on the base plate 1 is selected as the coordinate origin, the vertical crack length direction is selected as the x-axis, the crack length direction, i.e. the direction of the line connecting the two columns on the base plate 1, is selected as the y-axis, and the direction perpendicular to the plane where the crack is located is selected as the z-axis. The x, y and z-axis directions conform to the left-hand coordinate system. Points A, B and C are set as fixed reference points, wherein AO and BO represent two horizontal elastic materials respectively, and CO represents a vertical elastic material. When the crack is not expanded, the elastic material 5 is in the initial state, and the lengths are 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 the three points A, B and C, and the other end moves to a new position. In order to determine the spatial coordinates of the point O' on the moving part 3, a spatial geometry method can be used. Specifically, three spherical surfaces are constructed with the three points A, B and C as centers and AO', BO' and CO' as radii. These three spherical surfaces intersect at two points in space, one of which has a z value greater than 0 and the other of which has a z value less than 0. Since the moving part cannot pass through the bottom plate, the z value cannot be greater than 0, so 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 point O' sought.

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

[0068] In specific embodiments, in S104, the formula for obtaining the individual direction change amount is:

[0069] Opening and closing direction change amount:

[0070] Δx = x2 - x1

[0071] Shear direction change amount:

[0072] Δy = y2 - y1

[0073] Settlement direction change amount:

[0074] Δz = z2 - z1

[0075] In specific embodiments, the calculation system of the three-way joint meter based on the fiber grating sensing technology comprises:

[0076] A measurement module is closely connected to the spatial coordinate calculation module, and the core components include a fiber grating and a fiber grating demodulator. The main function of this module is to measure and record the center wavelength change of the fiber grating in real time, and transmit the data to the spatial coordinate calculation module for processing. The fiber grating, as a high-sensitivity strain sensing element, can accurately reflect the deformation state of the elastic material through the small shift of its center wavelength.

[0077] A 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 grating center wavelength data provided by the measurement module. Through complex algorithms, these wavelength data are converted into strain and length change amount, 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] An output module is connected with the spatial coordinate calculation module, and is responsible for receiving and processing the spatial coordinate values output by the spatial coordinate calculation module. According to the coordinate values, the output module calculates the change amounts of the crack in the opening, shearing and subsidence directions. These data are displayed in the form of accurate numbers, which provide important support for structure health monitoring and geological disaster warning.

[0079] In specific embodiments, the computer device comprises a memory and a processor, the memory stores a computer program, and the computer program is executed by the processor to make the processor execute the steps of the calculation method of the three-way joint meter based on the fiber grating sensing technology.

[0080] In specific embodiments, the computer readable storage medium stores a computer program, and the computer program is executed by the processor to make the processor execute the steps of the calculation method of the three-way joint meter based on the fiber grating sensing technology.

[0081] In specific embodiments, the information data processing terminal is used to realize the calculation system of the three-way joint 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 application, and not to limit it. Although the foregoing embodiments have been described in detail, those skilled in the art should understand that they can still modify the technical solutions described in the embodiments, or equivalently replace some or all of the technical features. Such modifications or replacements do not change the essence of the corresponding technical solutions, and do not exceed the protection scope of the embodiments of the present application.

Claims

1. A three-way joint meter based on fiber grating sensing technology, characterized in that, The three-way joint meter comprises a base plate, a top cover, a moving part, a positioning part, an elastic material and an optical fiber grating; The base plate and the top cover jointly form a protective shell of the three-way joint meter, and are installed on one side of a crack as a fixed reference point during monitoring; The moving part comprises a moving part base plate, a moving part stand and a hook, the moving part stand is fixed on the moving part base plate, and the hook is fixed on one end of the moving part base plate; the moving part base 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 part base plate and the base plate and the top cover directly reflects the dynamic development process of the crack; The positioning part assists the moving part to complete initial positioning, ensures that the starting position of the moving part is consistent with the calibration state, and realizes accurate measurement of the actual expansion of the crack; The elastic material can rapidly deform at the moment of force and immediately recover after the external force is removed, thereby realizing instant response to deformation; the elastic material is fixed between the moving part and the base plate and the top cover, and is used for measuring the relative displacement between the moving part and the base plate and the top cover; The optical fiber grating is a passive filter device, which is pasted on the elastic material and is used for real-time monitoring of the strain state of the elastic material, thereby reflecting the dynamic change of the crack.

2. The tri-directional joint meter of claim 1, wherein, The base plate is square and is provided with two non-coincident stands for fixing the elastic material; a rectangular hole is formed in the base plate, so that the stand of the moving part can penetrate into the hole and limit the maximum displacement of the moving part; the elastic material comprises three elastic materials, two horizontal elastic materials and one vertical elastic material, wherein the two horizontal elastic materials are connected with the stand of the moving part and the two stands on the base plate respectively, and the vertical elastic material is connected with the hook on the moving part and the top cover; the three elastic materials are arranged in a non-collinear manner and measure the relative displacement between the base 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 perpendicular to the plane in which the two horizontal elastic materials are located; the optical fiber grating comprises four optical fibers, three of which are strain optical fibers and are pasted on the three elastic materials for measuring the strain change of the three elastic materials, and the other one is a temperature optical fiber and is pasted on the base plate for monitoring the temperature change of the three-way joint meter and for temperature compensation of the strain measurement result.

3. A method of calculating the three-way joint meter according to claim 2, characterized in that, The method comprises the following steps: S101, measuring the center wavelengths of the three strain optical fibers and one temperature optical fiber; S102, calculating the strain of the elastic material by using the center wavelength difference of the strain optical fibers and performing temperature compensation by using the center wavelength difference of the temperature optical fiber; S103, calculating the length change of the elastic material; S104, obtaining the spatial coordinates of point O' and calculating the displacement change amount of point O to point O'; Wherein, O' is the initial fixed point of the moving part, and O is the point of the moving part after moving with the development of the crack.

4. The computational method of claim 3, wherein, In S102, the strain calculation formula is as follows: ； wherein is the strain of the elastic material, and are the center wavelength differences of the strain fiber and the temperature fiber, respectively, and are the initial center wavelengths of the strain fiber and the temperature fiber, respectively, is the effective photoelastic coefficient of the fiber grating.

5. The computational method of claim 3, wherein, In S103, the length change calculation formula of the elastic material is as follows: ； wherein is the change in length of the elastic material, is the original length of the elastic material.

6. The computational method of claim 3, wherein, In S104, the displacement change amount of the displacement part is calculated as follows: In three-dimensional space, a column A on the selected base plate is selected as the coordinate origin, the vertical crack length direction is taken as the x-axis, the crack length direction, that is, the direction of the line connecting the two columns on the base plate is taken as the y-axis, and the direction perpendicular to the plane where the crack is located is taken as the z-axis, the x, y and z-axis directions conform to the left-hand coordinate system; points A, B and C are set as fixed reference points, wherein AO and BO represent two horizontal elastic materials respectively, and CO represents a vertical elastic material; when the crack is not expanded, the elastic materials are in the initial state, and the lengths are AO, BO and CO respectively; When the crack develops, the elastic materials will deform, but one end thereof is still fixed at the three points A, B and C, and the other end moves to a new position; in order to determine the spatial coordinates of the point O' on the moving part, a spatial geometry method is adopted; specifically, three spherical surfaces are constructed with the three points A, B and C as centers and AO', BO' and CO' as radii; the three spherical surfaces intersect at two points in space, one of which has a z value greater than 0 and the other of which has a z value less than 0; since the moving part cannot pass through the base plate, the z value cannot be greater than 0, so the point with the z value greater than 0 is discarded, and the point with the z value less than 0 is retained, that is, the point O' is obtained. By solving the intersection points of the three spherical surfaces, the spatial coordinates (x2, y2, z2) of the point O' are obtained; at the same time, the spatial coordinates of the initial fixed point of the moving part, that is, the point O, are (x1, y1, z1); therefore, the relative displacement of the points O and O' is obtained by calculating the spatial distance difference between the points O and O'.

7. The computational method of claim 3, wherein, In S104, the formula for obtaining the direction change amount is: Opening and closing direction change amount: ； Shearing direction change amount: ； Settlement direction change amount: 。 8. A computing system for a three-way joint meter according to any one of claims 1-3, characterized in that, including: The measurement module is connected with the spatial coordinate calculation module, and is used to input the measured fiber grating central wavelength into the spatial coordinate calculation module; The measurement module includes a fiber grating and a fiber grating demodulator; The spatial coordinate calculation module is connected with the measurement module and the output module, and is used to set a coordinate system and convert the fiber grating central 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, and calculates the change amount in the opening and closing, shearing and settlement directions according to different spatial coordinates; The information data processing terminal is used to realize the computing system.

9. A computer device, comprising: The computer device includes a memory and a processor, the memory stores a computer program, and the computer program is executed by the processor to make the processor execute the computing method in any one of claims 3-7.

10. A computer readable storage medium storing a computer program, the computer program being executed by a processor to make the processor execute the computing method in any one of claims 3-7.

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