Slope three-dimensional deformation monitoring method and system

Abstract

The invention relates to a side slope three-dimensional deformation monitoring method and system, and belongs to the technical field of side slope monitoring, and the method comprises the steps: obtaining reflection spectrum data collected by an optical fiber sensing unit embedded in a side slope, the optical fiber sensing unit comprising a cylinder and a fiber grating wound on the cylinder; determining the bending direction and curvature data of the optical fiber sensing unit based on the reflection spectrum data; and based on the bending direction and curvature data, performing three-dimensional reconstruction on the slope deformation curve to obtain a three-dimensional slope deformation curve. According to the invention, the fiber bragg grating is arranged on the cylinder, so that the reflection spectrum data has anisotropy after the fiber sensing units with different bending directions and different bending rates are extruded and deformed, the bending direction and curvature data of the fiber sensing units are obtained by utilizing the characteristic of the anisotropy of the reflection spectrum data, and then three-dimensional reconstruction is carried out; the technical problem that a common fiber grating sensor cannot discriminate the direction in the prior art is effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of slope monitoring, and in particular to a three-dimensional slope deformation monitoring method and system. Background Art

[0002] Slope monitoring refers to long-term monitoring of slopes to understand the development patterns of their deformation and displacement, analyze slope stability, and provide a reliable basis for slope management and protection.

[0003] In the prior art, the traditional slope three-dimensional deformation monitoring method uses fiber grating sensors. Ordinary fiber grating flexible sensors calculate the strain by using the drift of the central wavelength of the reflection spectrum caused by the change in grid spacing after the fiber is subjected to force in the axial direction.

[0004] However, ordinary fiber Bragg grating flexible sensors are isotropic strain sensors. When the optical fiber is subjected to lateral force, the direction of the force cannot be determined based on the spectral information. Its application range is relatively narrow and it is difficult to meet the requirements of dynamic three-dimensional deformation monitoring of slopes in complex environments. Summary of the invention

[0005] In view of this, it is necessary to provide a three-dimensional slope deformation monitoring method and system to solve the technical problem that ordinary fiber grating flexible sensors in the prior art cannot determine the direction of force and are difficult to meet the requirements of dynamic three-dimensional deformation monitoring of slopes in complex environments.

[0006] In order to solve the above problems, on the one hand, the present invention provides a three-dimensional slope deformation monitoring method, comprising: Acquiring reflection spectrum data collected by an optical fiber sensitive unit buried in the slope, wherein the optical fiber sensitive unit includes a cylinder and an optical fiber Bragg grating wound around the cylinder; Based on the reflection spectrum data, determining the bending direction and curvature data of the optical fiber sensing unit; Based on the bending direction and curvature data, the slope deformation curve is three-dimensionally reconstructed to obtain a three-dimensional slope deformation curve.

[0007] In a possible implementation, at least two optical fiber sensitive units are provided, the cylinders of adjacent optical fiber sensitive units are connected via flanges, and the optical fiber gratings of adjacent optical fiber sensitive units are connected via optical fibers.

[0008] In a possible implementation, the optical fiber sensitive unit is further sheathed with a protective tube.

[0009] In a possible implementation, determining the bending direction and curvature data of the optical fiber sensing unit based on the reflection spectrum data includes: The reflection spectrum data is input into a well-trained deep learning model to obtain the bending direction and curvature data of the optical fiber sensitive unit. The deep learning model includes an input layer, a shared convolutional layer and a double-headed output layer connected in sequence. The input layer is used to input the reflection spectrum data. The shared convolutional layer includes several groups of convolutional layers and a pooling layer whose input end is connected to the output end of the convolutional layer. The double-headed output layer includes two output heads. The first output head is used to fit the bending direction data of the output optical fiber sensitive unit, and the second output head is used to fit the curvature data of the output optical fiber sensitive unit.

[0010] In a possible implementation, based on the bending direction and curvature data, a three-dimensional reconstruction of the slope deformation curve is performed to obtain a three-dimensional slope deformation curve, including: Based on the geometric relationship of the optical fiber sensitive unit, as well as the bending direction and curvature data, the slope deformation curve is reconstructed in two dimensions to obtain a two-dimensional slope deformation curve; The two-dimensional slope deformation curve is reconstructed three-dimensionally based on the bending direction data of each optical fiber sensitive unit to obtain a three-dimensional slope deformation curve.

[0011] In a possible implementation, at least two optical fiber sensing units are provided, and adjacent optical fiber sensing units are connected end to end; Based on the geometric relationship of the fiber optic sensitive unit, as well as the bending direction and curvature data, the slope deformation curve is reconstructed in two dimensions to obtain a two-dimensional slope deformation curve, including: Each section of the optical fiber sensitive unit is divided into a straight line segment at the head end, a circular arc at the midpoint and a straight line segment at the tail end, the circular arc is regarded as a uniform curve, and the connection between the straight line segment at the head end, the circular arc and the straight line segment at the tail end is regarded as smooth tangent, so as to construct a two-dimensional curve model of the optical fiber sensitive unit; The angle between the straight line segment at the head end of the first fiber optic sensitive unit and the coordinate axis is selected by traversing within the first preset range, and the arc length of each fiber optic sensitive unit is selected by traversing within the second preset range; Based on the two-dimensional curve model, the measured coordinate value of the head end of the first section of the optical fiber sensitive unit, the angle, the arc length, and the bending direction and curvature data, starting from the head end of the first section of the optical fiber sensitive unit, the coordinates of the head and tail end points of each section of the optical fiber sensitive unit are calculated in sequence, and finally the calculated coordinate value of the tail end of the last section of the optical fiber sensitive unit is obtained; Calculate the deviation between the calculated value of the tail end coordinate of the last section of the optical fiber sensitive unit and the measured value of the tail end coordinate of the last section of the optical fiber sensitive unit, select the angle and arc length corresponding to the minimum deviation, and determine the two-dimensional slope deformation curve based on the angle and arc length corresponding to the minimum deviation.

[0012] In a possible implementation, based on the two-dimensional curve model, the measured coordinate value of the head end of the first section of the optical fiber sensitive unit, the angle, the arc length, and the bending direction and curvature data, starting from the head end of the first section of the optical fiber sensitive unit, the coordinates of the head and tail end points of each section of the optical fiber sensitive unit are calculated in sequence, and finally the calculated coordinate value of the tail end of the last section of the optical fiber sensitive unit is obtained, including: S801, selecting the first section of the optical fiber sensitive unit as the current optical fiber sensitive unit, taking the head end coordinate measurement value of the first section of the optical fiber sensitive unit as the head end coordinate of the current section of the optical fiber sensitive unit, and determining the slope of the straight line segment at the head end of the current section of the optical fiber sensitive unit based on the angle; S802, calculating the coordinates of the connection point between the straight line segment at the head end and the circular arc according to the head end coordinates of the current section optical fiber sensitive unit, the slope of the straight line segment at the head end, and the arc length; S803, calculating the coordinates of the center of the curvature circle of the arc according to the bending direction and curvature data of the current section optical fiber sensitive unit, the coordinates of the connection point between the straight line segment at the head end and the arc, and the slope of the straight line segment at the head end, and calculating the coordinates of the connection point between the arc and the tail end straight line segment based on the coordinates of the center of the curvature circle; S804, calculating the tail end coordinates of the current node sensitive unit according to the geometric relationship between the center of the curvature circle and the straight line between the connection point of the arc and the tail end straight line segment and the vertical tail end straight line segment, the coordinates of the center of the curvature circle and the coordinates of the connection point of the arc and the tail end straight line segment; S805, taking the tail end coordinates of the current section sensitive unit as the head end coordinates of the next section sensitive unit, taking the slope of the straight line segment at the tail end of the current section sensitive unit as the slope of the straight line segment at the head end of the next section sensitive unit, and returning to step S802 until the tail end coordinate calculation value of the last section sensitive unit is calculated.

[0013] In a possible implementation, at least two optical fiber sensing units are provided, and adjacent optical fiber sensing units are connected end to end; The two-dimensional slope deformation curve is three-dimensionally reconstructed based on the bending direction data of each optical fiber sensitive unit to obtain a three-dimensional slope deformation curve, including: S901, embedding the two-dimensional slope deformation curve into a three-dimensional coordinate system to obtain an initial slope deformation curve, and using the first section of the optical fiber sensitive unit as the current section of the optical fiber sensitive unit; S902, determining a straight line parallel to the length direction of the initial state of the optical fiber sensitive unit and passing through the head end of the optical fiber sensitive unit of the current section as a rotation axis, rotating the initial slope deformation curve around the rotation axis to obtain an intermediate slope deformation curve; S903, retaining the three-dimensional slope deformation curve corresponding to the optical fiber sensitive unit of the current section in the intermediate slope deformation curve, and taking the slope deformation curves corresponding to the optical fiber sensitive units of all sections except the current section in the intermediate slope deformation curve as the initial slope deformation curve; S904: Use the next section of optical fiber sensitive unit as the current section of optical fiber sensitive unit, and return to step S902 until the target slope deformation curves corresponding to all sections of optical fiber sensitive units are obtained, and determine the final three-dimensional slope deformation curve based on the target slope deformation curve.

[0014] In a possible implementation, the method further includes an early warning module that issues an early warning signal when the curvature of the three-dimensional slope deformation curve is greater than a threshold value.

[0015] On the other hand, the present invention also provides a three-dimensional slope deformation monitoring system, comprising: A spectrum acquisition module, used to acquire reflection spectrum data collected by a fiber optic sensitive unit buried in the slope, wherein the fiber optic sensitive unit includes a cylinder and a fiber optic Bragg grating wound around the cylinder; A deformation prediction module, used to determine the bending direction and curvature data of the optical fiber sensitive unit based on the reflection spectrum data; The three-dimensional reconstruction module is used to perform three-dimensional reconstruction on the slope deformation curve based on the bending direction and curvature data to obtain a three-dimensional slope deformation curve.

[0016] The beneficial effects of the present invention are as follows: the three-dimensional deformation monitoring method of the slope provided by the present invention forms full coverage of 360° bending direction by winding the fiber optic Bragg grating on a cylinder, so that the reflected spectral data of the fiber optic sensitive units with different bending directions and different curvatures after being squeezed and deformed have anisotropy. By utilizing the anisotropy of the reflected spectral data, the bending direction and curvature data of the fiber optic sensitive units are obtained, and then three-dimensional reconstruction is performed, which effectively solves the technical problem that ordinary fiber optic Bragg grating sensors in the prior art cannot distinguish directions, meets the requirements of dynamic three-dimensional deformation monitoring of slopes in complex environments, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic flow chart of an embodiment of the slope three-dimensional deformation monitoring method provided by the present invention; Figure 2 A schematic structural diagram of an embodiment of the optical fiber sensing unit provided by the present invention; Figure 3 A schematic diagram of a distribution of a reflection spectrum provided by the present invention; Figure 4 A schematic diagram of the structure of an embodiment of the deep learning model provided by the present invention; Figure 5For the present invention Figure 1 A schematic flow chart of an embodiment of step S103; Figure 6 For the present invention Figure 5 A schematic flow chart of an embodiment of step S501; Figure 7 A schematic diagram of the structure of an embodiment of a two-dimensional curve model provided by the present invention; Figure 8 For the present invention Figure 6 A schematic flow chart of an embodiment of step S603; Fig. 9 For the present invention Figure 5 A schematic flow chart of an embodiment of step S502; Fig.10 A schematic diagram of an embodiment of the initial slope deformation curve provided by the present invention; Fig.11 A schematic diagram of an embodiment of the intermediate slope deformation curve provided by the present invention; Fig.12 A schematic diagram of the structure of an embodiment of the slope monitoring system provided by the present invention; Reference numerals: 10 - cylinder; 110 - threaded portion 110; 1110 - thread groove; 120 - connecting portion; 20 - flange. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0019] It should be understood that the schematic drawings are not drawn to scale. The flowchart used in the present invention shows the operations implemented according to some embodiments of the present invention. It should be understood that the operations of the flowchart can be implemented out of order, and the steps without logical context can be reversed in order or implemented simultaneously. In addition, those skilled in the art can add one or more other operations to the flowchart under the guidance of the content of the present invention, and can also remove one or more operations from the flowchart. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor methods and / or microcontroller methods.

[0020] The descriptions such as "first" and "second" involved in the embodiments of the present invention are only used to describe the implicit purpose, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the technical features defined as "first" and "second" may explicitly or implicitly include at least one of the features. "And / or" describes the association relationship of the associated objects, indicating that there may be three relationships, for example: A and / or B, which can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0021] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0022] The present invention provides a slope three-dimensional deformation monitoring method and system, which are described below respectively.

[0023] Figure 1 A schematic flow chart of an embodiment of the slope three-dimensional deformation monitoring method provided by the present invention is as follows: Figure 1 As shown, the slope three-dimensional deformation monitoring method 1 includes: S101, obtaining reflection spectrum data collected by a fiber optic sensitive unit buried in the slope, wherein the fiber optic sensitive unit includes a cylinder and a fiber optic Bragg grating wound around the cylinder; It should be noted that if Figure 2 As shown, the optical fiber sensitive unit includes a cylinder 10 and an optical fiber Bragg grating (not shown in the figure), a thread groove 1110 is provided on the side of the middle part of the cylinder 10, and the number of optical fiber Bragg gratings is set. The optical fiber Bragg gratings are annularly pasted on the groove wall of the thread groove 1110 for at least one circle to form a full coverage of 360° bending direction. Therefore, after the optical fiber sensitive unit is squeezed and deformed, the reflection spectrum has an irregular characteristic, and the FBG reflection spectra of different bending directions and different curvatures are different. The reflection spectrum is as shown in FIG. Figure 3 shown.

[0024] Considering that a cylinder with a too large cross-sectional outer diameter will affect sensitivity, a cylinder with a too small cross-sectional outer diameter will be easily damaged, too few turns of the fiber Bragg grating around the cylinder will affect accuracy, and too many turns of the fiber Bragg grating around the cylinder will affect cost, therefore, in some embodiments of the present invention, the number of fiber Bragg gratings is finally set to three. It should be noted that the number of fiber Bragg gratings can be adjusted according to actual needs and is not limited to three, and will not be described one by one here.

[0025] In order to meet actual monitoring needs, in some embodiments of the present invention, such as Figure 2 As shown, at least two fiber optic sensitive units are provided, and the cylinders 10 of adjacent fiber optic sensitive units are connected by flanges 20, and the fiber optic gratings of adjacent fiber optic sensitive units are connected by optical fibers. Therefore, different numbers of fiber optic sensitive units can be selected for splicing according to the detection depth, so as to realize the extended use of multi-point network monitoring, with good scalability and strong practicality. In addition, a PVC protective sleeve (not shown in the figure) is also provided around the outside of the fiber optic sensitive unit to protect the internal fiber optic sensitive unit.

[0026] S102, determining the bending direction and curvature data of the optical fiber sensing unit based on the reflection spectrum data; Considering that when detecting the reflection spectrum data, most conventional methods use the peak tracking method to detect the slight shift of the Bragg wavelength, which mainly include the direct method, the curve fitting method, the correlation-based method, the conversion-based method and the optimization-based technology. However, the common feature of these methods is that the detection accuracy is limited by the number of fiber Bragg grating spectrum sample points. The essence is that the grating spectrum range analyzed is relatively small, and the tolerance for the spectral deformation of the fiber Bragg grating of the present invention is low, which makes it difficult to apply to the complex situation of the present invention. Therefore, in some embodiments of the present invention, step S102 includes: inputting the reflection spectrum data into a well-trained deep learning model to obtain the bending direction and curvature data of the fiber sensitive unit.

[0027] By using the above-mentioned deep learning model to predict deformation of reflectance spectral data, the complex relationship between temperature and strain can be learned, thereby performing real-time temperature compensation, avoiding the problem of information loss in conventional spectral signal detection methods, improving measurement accuracy, and achieving efficient and accurate three-dimensional slope deformation monitoring in the absence of a clear physical model.

[0028] It should be noted that deep learning models such as Figure 4 As shown in the figure, a CNN network is used to construct the model, including an input layer, a shared convolution layer and a dual-head output layer connected in sequence; the input layer is used to input reflectance spectrum data; the shared convolution layer includes 4 groups of convolution layers and a pooling layer whose input end is connected to the output end of the convolution layer, the pooling layer is specifically a maximum pooling layer, and the relu activation function is used for activation processing between the convolution layer and the pooling layer; the dual-head output layer includes two output heads to perform the fitting task, the first output head is responsible for fitting the bending direction of the output fiber sensitive unit, and the second output head is responsible for fitting the curvature data of the output fiber sensitive unit, each output head includes multiple fully connected layers, and a dropout operation with a probability of 0.5 is used between the two fully connected layers; in the process of model optimization, the mean square error (MSE) loss function is used for optimization; it should be noted that the number of groups of convolution layers and pooling layers can be adjusted according to actual needs, and is not limited to 4, so they will not be described one by one here.

[0029] By adopting the above structure, the hidden layer feature representation of the network can be shared by multiple output heads, which means that the network can learn shared feature representations between different fitting tasks, thereby reducing data redundancy and improving the efficiency and generalization ability of the model. The use of operations such as multi-pooling and dropout can help alleviate the overfitting of the network.

[0030] S103, based on the bending direction and curvature data, three-dimensionally reconstructing the slope deformation curve to obtain a three-dimensional slope deformation curve.

[0031] In summary, the present invention forms full coverage of 360° bending direction by winding the fiber grating on a cylinder, so that the reflected spectral data of the fiber optic sensitive units with different bending directions and different curvatures are anisotropic after being squeezed and deformed. By utilizing the anisotropic characteristics of the reflected spectral data, the bending direction and curvature data of the fiber optic sensitive units are obtained, and then three-dimensional reconstruction is performed, which effectively solves the technical problem that ordinary fiber grating sensors in the prior art cannot distinguish directions, meets the requirements of dynamic three-dimensional deformation monitoring of slopes in complex environments, and has a wide range of applications.

[0032] In some embodiments of the present invention, Figure 5 As shown, step S103 includes: S501, based on the geometric relationship of the optical fiber sensitive unit, as well as the bending direction and curvature data, the slope deformation curve is reconstructed in two dimensions to obtain a two-dimensional slope deformation curve; S502 , reconstructing the two-dimensional slope deformation curve into three dimensions based on the bending direction data of each optical fiber sensitive unit to obtain a three-dimensional slope deformation curve.

[0033] In order to better perform two-dimensional reconstruction, in some embodiments of the present invention, such as Figure 6 As shown, step S501 includes: S601, dividing each section of the optical fiber sensitive unit into a straight line segment at the head end, an arc at the midpoint and a straight line segment at the tail end, considering the arc to be uniformly curved, and considering the connections between the straight line segment at the head end, the arc and the straight line segment at the tail end to be smoothly tangent, thereby constructing a two-dimensional curve model of the optical fiber sensitive unit; It should be noted that if Figure 2 As shown, the cylinder 10 includes a threaded portion 110 in the middle and connecting portions 120 at both ends. The thread groove 1110 is provided on the threaded portion 110. The elastic modulus of the threaded portion 110 is smaller than that of the connecting portion 120. The elastic modulus of the protective sleeve is the same as that of the threaded portion 110. Therefore, when the cylinder is deformed, the threaded portion 110 in the middle is bent and deformed first. Therefore, the optical fiber sensing unit can be abstracted as follows: Figure 7 The two-dimensional curve model shown in the figure defines a two-dimensional coordinate system , the initial state of the optical fiber sensing unit is along The axis is straight, The axis is perpendicular, defining the bending direction towards The positive direction of the axis is 0°, The negative direction of the axis is 180°, the first end of the first section of the optical fiber sensitive unit Fixed point; the optical fiber sensitive unit is provided with indivual, Point The head end of a fiber optic sensing unit, Point The end of the optical fiber sensing unit, For the The midpoint of the fiber sensitive unit, that is, the bonding point of the fiber Bragg grating ( Point measured bending angle and curvature ), arc Length is cm, assuming that the deformation at the arc is uniformly curved, the curvature is equal to The curvature at ,definition for The center of the circle of curvature is The central angle of , The radius of curvature circle ;neglect and The micro deformation can be regarded as a straight line segment, with smooth tangency at the connection. The end of the fiber optic sensing unit The next section is The head end of a fiber optic sensing unit coincidence; define coordinates , , , , , the coordinate measurement value of the first end of the optical fiber sensitive unit is known , the tail end coordinate measurement value of the last section of the optical fiber sensitive unit , the angle between the straight line segment at the head end of the first fiber optic sensitive unit and the X-axis , and Fiber optic sensing unit arc Arc length , according to the arc length and curvature The product of can be calculated Fiber optic sensing unit arc The central angle of .

[0034] S602, traversing and selecting the angle between the straight line segment at the head end of the first optical fiber sensitive unit and the coordinate axis within the first preset range, and traversing and selecting the arc length of each optical fiber sensitive unit within the second preset range; It should be noted that the first preset range is {30°, 32°, 34°, ..., 150°}, and the second preset range is {10, 15, 20}.

[0035] S603, based on the two-dimensional curve model, the coordinate measurement value of the head end of the first section of the optical fiber sensitive unit, the angle, the arc length, the bending direction and the curvature data, starting from the head end of the first section of the optical fiber sensitive unit, the coordinates of the head and tail end points of each section of the optical fiber sensitive unit are calculated in sequence, and finally the coordinate calculation value of the tail end of the last section of the optical fiber sensitive unit is obtained; It should be noted that the coordinate measurement value of the head end of the first section optical fiber sensitive unit and the coordinate measurement value of the tail end of the last section optical fiber sensitive unit are known, and the coordinate calculation value of the tail end of the last section optical fiber sensitive unit is calculated according to the coordinate measurement value of the head end of the first section optical fiber sensitive unit.

[0036] S604, calculating the deviation between the calculated coordinate value of the tail end of the last section of the optical fiber sensitive unit and the measured coordinate value of the tail end of the last section of the optical fiber sensitive unit, selecting the angle and arc length corresponding to the minimum deviation, and determining the two-dimensional slope deformation curve based on the angle and arc length corresponding to the minimum deviation.

[0037] It should be noted that the calculated coordinates of the tail end of the last section of the optical fiber sensitive unit are: , the tail end coordinate measurement value of the last section of the optical fiber sensitive unit: , the deviation is: , traverse all and The value of is completed and the minimum deviation is determined Corresponding and value.

[0038] In order to better calculate the tail end coordinate value of the last section of the optical fiber sensitive unit, in some embodiments of the present invention, such as Figure 8 As shown, step S603 includes: S801, selecting the first section of the optical fiber sensitive unit as the current optical fiber sensitive unit, taking the head end coordinate measurement value of the first section of the optical fiber sensitive unit as the head end coordinate of the current section of the optical fiber sensitive unit, and calculating the slope of the straight line segment at the head end of the current section of the optical fiber sensitive unit based on the included angle; It should be noted that the first end coordinate of the first section of the optical fiber sensitive unit is the measured value of the first end coordinate of the first section of the optical fiber sensitive unit, and the first end coordinate of the remaining optical fiber sensitive units is the tail end coordinate of the previous optical fiber sensitive unit. The slope of the straight line segment at the first end of the first section of the optical fiber sensitive unit is , the slope of the straight line segment at the head end of the remaining optical fiber sensitive unit is the slope of the straight line segment at the tail end of the previous optical fiber sensitive unit.

[0039] S802, calculating the coordinates of the connection point between the straight line segment at the head end and the circular arc according to the head end coordinates of the current section optical fiber sensitive unit, the slope of the straight line segment at the head end, and the arc length; It should be noted that if Figure 5 As shown, The parametric equation is:

[0040] In the formula, express The coordinates of the point on .

[0041] S803, calculating the coordinates of the center of the curvature circle of the arc according to the bending direction and curvature data of the current section optical fiber sensitive unit, the coordinates of the connection point between the straight line segment at the head end and the arc, and the slope of the straight line segment at the head end, and calculating the coordinates of the connection point between the arc and the straight line segment at the tail end based on the coordinates of the center of the curvature circle; It should be noted that if Figure 5 As shown, The center of the circle of curvature coordinate( )for:

[0042] In the formula, The bending direction angle of the optical fiber sensitive unit is ,when ,when ; but The parametric equation is as follows:

[0043]

[0044] In the formula, ( )express The coordinates of the upper point, As parameters, For point Corresponding parameters, For point Corresponding parameters, for the first section of the optical fiber sensitive unit .

[0045] S804, calculating the tail end coordinates of the current node sensitive unit according to the geometric relationship between the center of the curvature circle and the straight line between the connection point of the arc and the tail end straight line segment and the vertical tail end straight line segment, the coordinates of the center of the curvature circle and the coordinates of the connection point of the arc and the tail end straight line segment; It should be noted that due to ⊥ ,point ( ) and dot ( ) satisfies the following equation, point ( ) coordinates are:

[0046] The parametric equation is: .

[0047] S805, taking the tail end coordinates of the current section sensitive unit as the head end coordinates of the next section sensitive unit, taking the slope of the straight line segment at the tail end of the current section sensitive unit as the slope of the straight line segment at the head end of the next section sensitive unit, and returning to step S802 until the tail end coordinate calculation value of the last section sensitive unit is calculated.

[0048] In order to better perform three-dimensional reconstruction, in some embodiments of the present invention, such as Fig. 9 As shown, step S502 includes: S901, embedding the two-dimensional slope deformation curve into the three-dimensional coordinate system to obtain the initial slope deformation curve, and using the first section of the optical fiber sensitive unit as the current section of the optical fiber sensitive unit; It should be noted that the construction Fig.10 Shown Three-dimensional coordinate system, is the origin, that is, in the above two-dimensional coordinate plane Add to Axis to construct a three-dimensional coordinate system, the initial length direction of the optical fiber sensitive unit is The two-dimensional slope deformation curve is embedded into the three-dimensional coordinate system. The coordinates of the two-dimensional slope deformation curve in the spatial coordinate system are ,in, is the original two-dimensional coordinate value.

[0049] S902, determining a straight line parallel to the length direction of the initial state of the optical fiber sensitive unit and passing through the head end of the optical fiber sensitive unit of the current section as a rotation axis, rotating the initial slope deformation curve around the rotation axis, and obtaining an intermediate slope deformation curve; It should be noted that in Fig.10 In the three-dimensional coordinate system shown, the rotation axis is Axis; bending direction angle for Tilt direction and Plane angle, that is, the three-dimensional curve The projection curve on the plane The angle between the axes The positive direction of the axis is 0°, and the angle increases in the counterclockwise bending direction; define the rotation angle of the initial slope deformation curve , Indicates counterclockwise rotation. Indicates clockwise rotation. hour, ,when hour, , .

[0050] S903, selecting a target slope deformation curve corresponding to the optical fiber sensitive unit of the current section from the intermediate slope deformation curve, and taking the slope deformation curves corresponding to the optical fiber sensitive units of all sections except the current section in the intermediate slope deformation curve as the initial slope deformation curve; It should be noted that, taking a section of optical fiber sensitive unit as an example, Fig.10 The initial slope deformation curve ABCD shown is rotated After the angle, we get Fig.11 The deformation curve of the intermediate slope is shown , the three-dimensional slope deformation curve corresponding to the fiber optic sensitive unit in the current section exist The projection curve on the plane The angle between the axes is .

[0051] S904: Use the next section of optical fiber sensitive unit as the current section of optical fiber sensitive unit, and return to step S902 until the target slope deformation curves corresponding to all sections of optical fiber sensitive units are obtained, and determine the final three-dimensional slope deformation curve based on the target slope deformation curve.

[0052] In some embodiments of the present invention, the method also includes comparing the three-dimensional slope deformation curve with the original state curve of the monitored slope, and when the curvature of the three-dimensional slope deformation curve is greater than a threshold, issuing a warning signal, specifically popping up a "red" warning identification symbol on the monitoring display interface.

[0053] In order to better implement a three-dimensional slope deformation monitoring method in an embodiment of the present invention, based on a three-dimensional slope deformation monitoring method, correspondingly, Fig.12 As shown, the embodiment of the present invention further provides a slope monitoring system 1200, including: The spectrum acquisition module 1201 is used to acquire the reflection spectrum data collected by the optical fiber sensitive unit buried in the slope, the optical fiber sensitive unit includes a cylinder and an optical fiber Bragg grating wound on the cylinder; It should be noted that, specifically in terms of hardware, the spectrum acquisition module 1201 includes a fiber optic sensitive unit and a demodulator. The demodulator is connected to the fiber optic sensitive unit via an optical cable. Only optical signals are transmitted between the demodulator and the fiber optic sensitive unit. When in use, a broadband swept-frequency light source is first input into the fiber optic sensitive unit, and then three non-overlapping and irregular reflected spectrum optical information transmitted from the fiber optic sensitive unit are obtained, and the reflected spectrum optical signal is converted into reflected spectrum data.

[0054] The deformation prediction module 1202 is used to determine the bending direction and curvature data of each optical fiber sensitive unit based on the reflection spectrum data; The three-dimensional reconstruction module 1203 is used to perform three-dimensional reconstruction on the slope deformation curve based on the bending direction and curvature data to obtain a three-dimensional slope deformation curve.

[0055] It should be noted that, specifically in terms of hardware, the deformation prediction module 1202 and the three-dimensional reconstruction module 1203, as well as the early warning function are integrated on the monitoring computer. The demodulator is also controlled by the monitoring software installed on the monitoring computer, and the control instructions are sent to the sensor signal demodulator through the network interface. The sensor signal demodulator injects broadband scanning laser into the optical fiber sensitive unit through the optical fiber.

[0056] The slope monitoring system 1200 provided in the above embodiment can implement the technical solution described in the above embodiment of the three-dimensional slope deformation monitoring method. The specific implementation principles of the above units can refer to the corresponding contents in the above embodiment of the three-dimensional slope deformation monitoring method, which will not be repeated here.

[0057] The above is a detailed introduction to a three-dimensional slope deformation monitoring method provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for technical personnel in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

[0058] The above are only preferred specific implementations of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A three-dimensional slope deformation monitoring method, characterized in that: include: Acquiring reflection spectrum data collected by an optical fiber sensitive unit buried in the slope, wherein the optical fiber sensitive unit includes a cylinder and an optical fiber Bragg grating wound around the cylinder; Based on the reflection spectrum data, determining the bending direction and curvature data of the optical fiber sensing unit; Based on the bending direction and curvature data, the slope deformation curve is three-dimensionally reconstructed to obtain a three-dimensional slope deformation curve.

2. The three-dimensional slope deformation monitoring method according to claim 1 is characterized in that: At least two optical fiber sensitive units are provided, the cylinders of adjacent optical fiber sensitive units are connected via flanges, and the optical fiber gratings of adjacent optical fiber sensitive units are connected via optical fibers.

3. The three-dimensional slope deformation monitoring method according to claim 1 is characterized in that: The optical fiber sensitive unit is also sheathed with a protective tube.

4. The three-dimensional slope deformation monitoring method according to claim 1 is characterized in that: Determining the bending direction and curvature data of the optical fiber sensing unit based on the reflection spectrum data includes: The reflection spectrum data is input into a well-trained deep learning model to obtain the bending direction and curvature data of the optical fiber sensitive unit. The deep learning model includes an input layer, a shared convolutional layer and a double-headed output layer connected in sequence. The input layer is used to input the reflection spectrum data. The shared convolutional layer includes several groups of convolutional layers and a pooling layer whose input end is connected to the output end of the convolutional layer. The double-headed output layer includes two output heads. The first output head is used to fit the bending direction data of the output optical fiber sensitive unit, and the second output head is used to fit the curvature data of the output optical fiber sensitive unit.

5. The three-dimensional slope deformation monitoring method according to claim 1, characterized in that: Based on the bending direction and curvature data, the slope deformation curve is three-dimensionally reconstructed to obtain a three-dimensional slope deformation curve, including: Based on the geometric relationship of the optical fiber sensitive unit, as well as the bending direction and curvature data, the slope deformation curve is reconstructed in two dimensions to obtain a two-dimensional slope deformation curve; The two-dimensional slope deformation curve is three-dimensionally reconstructed based on the bending direction data of each optical fiber sensitive unit to obtain a three-dimensional slope deformation curve.

6. The three-dimensional slope deformation monitoring method according to claim 5, characterized in that: At least two optical fiber sensitive units are provided, and adjacent optical fiber sensitive units are connected end to end; Based on the geometric relationship of the fiber optic sensitive unit, as well as the bending direction and curvature data, the slope deformation curve is reconstructed in two dimensions to obtain a two-dimensional slope deformation curve, including: Each section of the optical fiber sensitive unit is divided into a straight line segment at the head end, a circular arc at the midpoint and a straight line segment at the tail end, the circular arc is regarded as a uniform curve, and the connection between the straight line segment at the head end, the circular arc and the straight line segment at the tail end is regarded as smooth tangent, so as to construct a two-dimensional curve model of the optical fiber sensitive unit; The angle between the straight line segment at the head end of the first fiber optic sensitive unit and the coordinate axis is selected by traversing within the first preset range, and the arc length of each fiber optic sensitive unit is selected by traversing within the second preset range; Based on the two-dimensional curve model, the measured coordinate value of the head end of the first section of the optical fiber sensitive unit, the angle, the arc length, and the bending direction and curvature data, starting from the head end of the first section of the optical fiber sensitive unit, the coordinates of the head and tail end points of each section of the optical fiber sensitive unit are calculated in sequence, and finally the calculated coordinate value of the tail end of the last section of the optical fiber sensitive unit is obtained; Calculate the deviation between the calculated value of the tail end coordinate of the last section of the optical fiber sensitive unit and the measured value of the tail end coordinate of the last section of the optical fiber sensitive unit, select the angle and arc length corresponding to the minimum deviation, and determine the two-dimensional slope deformation curve based on the angle and arc length corresponding to the minimum deviation.

7. The three-dimensional slope deformation monitoring method according to claim 6, characterized in that: Based on the two-dimensional curve model, the measured coordinate value of the head end of the first section of the optical fiber sensitive unit, the angle, the arc length, and the bending direction and curvature data, starting from the head end of the first section of the optical fiber sensitive unit, the coordinates of the head and tail endpoints of each section of the optical fiber sensitive unit are calculated in sequence, and finally the calculated coordinate value of the tail end of the last section of the optical fiber sensitive unit is obtained, including: S801, selecting the first section of the optical fiber sensitive unit as the current optical fiber sensitive unit, taking the head end coordinate measurement value of the first section of the optical fiber sensitive unit as the head end coordinate of the current optical fiber sensitive unit, and determining the slope of the straight line segment at the head end of the current section of the optical fiber sensitive unit based on the angle; S802, calculating the coordinates of the connection point between the straight line segment at the head end and the circular arc according to the head end coordinates of the current section optical fiber sensitive unit, the slope of the straight line segment at the head end, and the arc length; S803, calculating the coordinates of the center of the curvature circle of the arc according to the bending direction and curvature data of the current section optical fiber sensitive unit, the coordinates of the connection point between the straight line segment at the head end and the arc, and the slope of the straight line segment at the head end, and calculating the coordinates of the connection point between the arc and the tail end straight line segment based on the coordinates of the center of the curvature circle; S804, calculating the tail end coordinates of the current node sensitive unit according to the geometric relationship between the center of the curvature circle and the straight line between the connection point of the arc and the tail end straight line segment and the vertical tail end straight line segment, the coordinates of the center of the curvature circle and the coordinates of the connection point of the arc and the tail end straight line segment; S805, taking the tail end coordinates of the current section sensitive unit as the head end coordinates of the next section sensitive unit, taking the slope of the straight line segment at the tail end of the current section sensitive unit as the slope of the straight line segment at the head end of the next section sensitive unit, and returning to step S802 until the tail end coordinate calculation value of the last section sensitive unit is calculated.

8. The three-dimensional slope deformation monitoring method according to claim 5, characterized in that: At least two optical fiber sensitive units are provided, and adjacent optical fiber sensitive units are connected end to end; The two-dimensional slope deformation curve is three-dimensionally reconstructed based on the bending direction data of each optical fiber sensitive unit to obtain a three-dimensional slope deformation curve, including: S901, embedding the two-dimensional slope deformation curve into a three-dimensional coordinate system to obtain an initial slope deformation curve, and using the first section of the optical fiber sensitive unit as the current section of the optical fiber sensitive unit; S902, determining a straight line parallel to the length direction of the initial state of the optical fiber sensitive unit and passing through the head end of the optical fiber sensitive unit of the current section as a rotation axis, rotating the initial slope deformation curve around the rotation axis to obtain an intermediate slope deformation curve; S903, retaining the three-dimensional slope deformation curve corresponding to the optical fiber sensitive unit of the current section in the intermediate slope deformation curve, and taking the slope deformation curves corresponding to the optical fiber sensitive units of all sections except the current section in the intermediate slope deformation curve as the initial slope deformation curve; S904: Use the next section of optical fiber sensitive unit as the current section of optical fiber sensitive unit, and return to step S902 until the target slope deformation curves corresponding to all sections of optical fiber sensitive units are obtained, and determine the final three-dimensional slope deformation curve based on the target slope deformation curve.

9. The three-dimensional slope deformation monitoring method according to claim 1, characterized in that: The method further comprises an early warning module, which issues an early warning signal when the curvature of the three-dimensional slope deformation curve is greater than a threshold value.

10. A slope monitoring system, characterized in that: include: A spectrum acquisition module, used to acquire reflection spectrum data collected by a fiber optic sensitive unit buried in the slope, wherein the fiber optic sensitive unit includes a cylinder and a fiber optic Bragg grating wound around the cylinder; A deformation prediction module, used to determine the bending direction and curvature data of the optical fiber sensitive unit based on the reflection spectrum data; The three-dimensional reconstruction module is used to perform three-dimensional reconstruction on the slope deformation curve based on the bending direction and curvature data to obtain a three-dimensional slope deformation curve.

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