Highway facility safety monitoring equipment and method based on self-sensing geotechnical cable

Abstract

The invention provides a highway facility safety monitoring device and method based on a self-sensing geotechnical cable, which are applied to the technical field of highway slope deformation monitoring, and the device comprises a self-sensing piezoelectric geotechnical cable laid inside a highway slope, a self-sensing signal acquisition module, a data processing module and a monitoring result output module; the self-sensing signal acquisition module is used for acquiring and analyzing an impedance signal and a voltage signal of the self-sensing piezoelectric geotechnical cable and sending impedance data and voltage data obtained through analysis to the data processing module; the data processing module calculates the deformation of the self-sensing piezoelectric geotechnical cable according to the impedance data and the voltage data, and sends an early warning to the monitoring result output module; and the monitoring result output module outputs early warning. According to the highway facility safety monitoring equipment and method provided by the invention, the technical problems that the traditional highway slope deformation monitoring equipment depends on manual operation and has high requirements on the smoothness of sight lines between observation points are solved, and the monitoring precision of highway slope deformation is improved.

Description

Technical Field

[0001] The invention relates to the field of highway slope deformation monitoring, and in particular to a highway facility safety monitoring device and method based on a self-sensing geotechnical cable. Background Art

[0002] Highway slope deformation monitoring is one of the important measures to ensure the safe operation of highways. It is a technical means to conduct long-term, real-time monitoring and data analysis of the slopes on both sides of the highway. It aims to monitor the displacement and deformation of the slopes and predict the stability of the slopes so as to timely discover and deal with potential safety hazards, take corresponding safety protection measures, prevent the occurrence of slope instability accidents, ensure the safe operation of the highway, and provide a scientific basis for the maintenance and reinforcement of highway slopes.

[0003] Traditional highway slope deformation monitoring equipment (such as total station, level) has the following disadvantages:

[0004] (1) The measurement process relies on manual operation, which requires manual instrument setting, target aiming, and data reading. The degree of automation is low and the work efficiency is low.

[0005] (2) There is a high requirement for unobstructed sight between observation points. Observation can only be carried out if there is unobstructed sight between observation points;

[0006] (3) The measurement accuracy is limited. On the one hand, the measurement process relies on manual operation and there are visual errors. On the other hand, the external environment such as external light and temperature will affect the measurement results to a certain extent, which leads to the limited monitoring accuracy of the equipment.

[0007] The piezoelectric effect of polyvinylidene fluoride piezoelectric film refers to the fact that when the polyvinylidene fluoride piezoelectric film is subjected to external force, it will undergo slight mechanical deformation and generate positive and negative charges on the inner and outer surfaces respectively. When the external force is removed, the positive and negative charges on the upper and lower surfaces dissipate. This phenomenon of converting mechanical energy into electrical energy is called the "positive piezoelectric effect."

[0008] The impedance strain effect of polyvinylidene fluoride piezoelectric film refers to the fact that when the polyvinylidene fluoride piezoelectric film is subjected to external force, its internal charge distribution and molecular structure will change, resulting in a change in impedance.

[0009] The present invention proposes a highway facility safety monitoring device and method based on self-sensing geotextile cables. The self-sensing geotextile cables are distributed inside the highway slopes, the piezoelectric effect and impedance strain effect of polyvinylidene fluoride piezoelectric film are utilized, and the voltage signal changes and impedance signal changes of the polyvinylidene fluoride piezoelectric film are monitored to monitor the deformation of the highway slopes to solve the above technical problems. Summary of the invention

[0010] The present invention provides a highway facility safety monitoring device and method based on self-sensing geotextile cables, which solves the technical problems that traditional highway slope deformation monitoring equipment relies on manual operation and has high requirements for unobstructed sight lines between observation points, and improves the monitoring accuracy of highway slope deformation.

[0011] According to a first aspect of the present invention, there is provided a highway facility safety monitoring device based on a self-sensing geotechnical cable, the device comprising a self-sensing piezoelectric geotechnical cable laid inside a highway slope, a self-sensing signal acquisition module connected to the self-sensing piezoelectric geotechnical cable via a data line, a data processing module connected to the self-sensing signal acquisition module via a network, and a monitoring result output module connected to the data processing module via a network;

[0012] The self-sensing signal acquisition module is used to collect and analyze the impedance signal and voltage signal of the self-sensing piezoelectric geotechnical cable, and send the impedance data and voltage data obtained by analysis to the data processing module;

[0013] The data processing module calculates the three-dimensional deformation value of the self-sensing piezoelectric geotextile cable according to the impedance data and the voltage data sent by the self-sensing signal acquisition module, and sends the self-sensing piezoelectric geotextile cable deformation warning and highway slope landslide warning to the monitoring result output module;

[0014] The monitoring result output module outputs the self-sensing piezoelectric geocable deformation warning and highway slope landslide warning sent by the data processing module.

[0015] Furthermore, the self-sensing piezoelectric geotechnical cable comprises a conductive core, a polyvinylidene fluoride piezoelectric film wrapped around the outside of the conductive core, and an insulating protective sleeve wrapped around the outside of the polyvinylidene fluoride piezoelectric film;

[0016] A plurality of conductive electrodes are arranged on the inner surface of the polyvinylidene fluoride piezoelectric film, and the conductive electrodes are embedded in the surface of the conductive core.

[0017] Further, the conductive electrode array is arranged on the polyvinylidene fluoride piezoelectric film;

[0018] The conductive electrodes include positive conductive electrodes and negative conductive electrodes, and the positive conductive electrodes and the negative conductive electrodes are alternately arranged along the direction of the self-sensing piezoelectric geotechnical cable;

[0019] The conductive electrodes include several groups of positive conductive modules and several groups of negative conductive modules;

[0020] Each group of the positive conductive modules includes a plurality of the positive conductive electrodes, and each group of the positive conductive electrodes is located on the same cross section of the self-sensing piezoelectric geotechnical cable;

[0021] Each group of the negative conductive modules includes a plurality of the negative conductive electrodes, and each group of the negative conductive electrodes is located on the same cross section of the self-sensing piezoelectric geotechnical cable.

[0022] Further, the self-sensing signal acquisition module includes an impedance signal acquisition module and a voltage signal acquisition module;

[0023] Two ends of the impedance signal acquisition module are respectively connected to the adjacent positive conductive electrode and the negative conductive electrode;

[0024] Two ends of the voltage signal acquisition module are respectively connected to the adjacent positive conductive electrode and the negative conductive electrode.

[0025] Furthermore, the impedance signal acquisition module is an impedance meter, and the voltage signal acquisition unit is an oscilloscope.

[0026] According to a second aspect of the present invention, there is provided a method for safety monitoring of highway facilities based on a self-sensing geotechnical cable, comprising the following steps:

[0027] S1. When the road slope is deformed, the self-sensing piezoelectric geotextile cable is mechanically deformed due to mechanical force;

[0028] S2, the self-sensing piezoelectric geotextile cable after mechanical deformation will generate an impedance signal and a voltage signal;

[0029] S3, the self-sensing signal acquisition module acquires and analyzes the impedance signal and voltage signal of the self-sensing piezoelectric geotechnical cable, and sends the impedance data and voltage data obtained by the analysis to the data processing module;

[0030] S4, the data processing module calculates the three-dimensional deformation value of the self-sensing piezoelectric geotextile cable according to the impedance data and the voltage data sent by the self-sensing signal acquisition module, and sends the self-sensing piezoelectric geotextile cable deformation warning and highway slope landslide warning to the monitoring result output module;

[0031] S5, the monitoring result output module outputs the self-sensing piezoelectric geotechnical cable deformation warning and highway slope landslide warning sent by the data processing module;

[0032] In step S2, the principle of generating the impedance signal and the voltage signal is as follows:

[0033] Based on the piezoelectric effect, when the polyvinylidene fluoride piezoelectric film in the self-sensing geotechnical cable is subjected to mechanical force, on the one hand, the positive and negative charges inside the polyvinylidene fluoride piezoelectric film will undergo relative displacement, thereby generating a voltage signal. On the other hand, the impedance characteristic of the polyvinylidene fluoride piezoelectric film will also change due to the mechanical force, thereby generating an impedance signal.

[0034] Further, step S3 specifically includes the following steps:

[0035] S31. The impedance signal acquisition module acquires the impedance signal between adjacent positive conductive electrodes and negative conductive electrodes, calculates the normalized impedance of the polyvinylidene fluoride piezoelectric film between adjacent positive conductive electrodes and negative conductive electrodes according to the impedance signal, and sends the normalized impedance to the data processing module.

[0036] S32. The voltage signal acquisition module acquires the voltage signal between adjacent positive conductive electrodes and negative conductive electrodes, calculates the peak voltage and the effective value voltage of the polyvinylidene fluoride piezoelectric film between adjacent positive conductive electrodes and negative conductive electrodes according to the voltage signal, and sends the peak voltage and the effective value voltage to the data processing module.

[0037] Further, step S4 specifically includes the following steps:

[0038] S41. The data processing module calculates the three-dimensional deformation value of the polyvinylidene fluoride piezoelectric film between adjacent positive conductive electrodes and negative conductive electrodes according to the received normalized impedance. When the three-dimensional deformation value reaches or exceeds the system preset three-dimensional deformation threshold, it sends the self-sensing geotechnical cable deformation warning to the monitoring result output module;

[0039] Among them, the three-dimensional deformation value of the polyvinylidene fluoride piezoelectric film includes: the strain value, the vertical direction displacement value, and the shear displacement value of the polyvinylidene fluoride piezoelectric film between adjacent positive conductive electrodes and negative conductive electrodes. The vertical direction displacement value refers to the displacement of the polyvinylidene fluoride piezoelectric film in the direction of the connection line of two conductive electrodes that are axisymmetric about the axis center on the same cross-section of the self-sensing geotechnical cable;

[0040] The self-sensing geotechnical cable deformation warning includes self-sensing geotechnical cable strain over-threshold warning, self-sensing geotechnical cable vertical direction displacement over-threshold warning, and self-sensing geotechnical cable shear displacement over-threshold warning;

[0041] S42, the data processing module determines whether a landslide occurs on the highway slope according to the received peak voltage and the effective value voltage, and sends a highway slope landslide warning to the monitoring result output module when a landslide occurs on the highway slope.

[0042] Furthermore, the monitoring result output module outputs the received self-sensing geotechnical cable deformation warning and the highway slope landslide warning.

[0043] The technical effects of the present invention are as follows:

[0044] (1) The present invention avoids the influence of external environment such as external light and temperature on the measurement results by laying the self-sensing geotechnical cable inside the slopes on both sides of the highway. On the one hand, it improves the measurement accuracy, and on the other hand, it enables the equipment to adapt to more monitoring environments;

[0045] (2) The highway facility safety monitoring system based on the self-sensing geocable proposed in the present invention utilizes the piezoelectric effect and impedance strain effect of the polyvinylidene fluoride piezoelectric film. It can collect the voltage signal and impedance signal of the polyvinylidene fluoride piezoelectric film in real time to monitor the strain, vertical displacement, shear displacement of the self-sensing geocable and whether the highway slope is sliding. When the highway slope is deformed, the corresponding self-sensing geocable strain over-threshold warning, self-sensing geocable vertical displacement over-threshold warning, and self-sensing geocable shear displacement over-threshold warning are automatically triggered. When the highway slope slides, the highway landslide warning is automatically triggered without manual intervention, thereby improving work efficiency and real-time monitoring.

[0046] It should be understood that the contents described in the summary of the invention are not intended to limit the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The above and other features, advantages and aspects of the embodiments of the present invention will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. The accompanying drawings are provided for a better understanding of the present invention and do not constitute a limitation of the present invention. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements, wherein:

[0048] Figure 1 Schematic diagram of the structure of the self-sensing geotextile cable.

[0049] Figure 2 Schematic diagram of the structure of the self-sensing geotextile cable.

[0050] Figure 3 Schematic diagram of the layout of self-sensing geotextile cables on highway slopes.

[0051] Figure 4 Strain-normalized impedance curve of self-sensing geotextile cable.

[0052] Figure 5 This is the deformation diagram at the conductive electrode of the self-sensing geotextile cable.

[0053] Figure 6 Parameter analysis of shear displacement-normalized impedance model for self-sensing geotextile cables.

[0054] Figure 7 Shear displacement-voltage curve of self-sensing geotextile cable.

[0055] The accompanying drawings are marked as follows: 1. conductive electrode; 11. positive conductive electrode; 12. negative conductive electrode; 2. conductive core; 3. polyvinylidene fluoride piezoelectric film; 4. insulating protective cover; 5. data line; 6. self-sensing signal acquisition module. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] In addition, the term "and / or" in this article is only a description of the association relationship between the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0058] Reference Figure 1-2 As shown, the present invention proposes a highway facility safety monitoring device based on a self-sensing geotechnical cable, comprising a self-sensing piezoelectric geotechnical cable 7 laid inside a highway slope, a self-sensing signal acquisition module 6 connected to the self-sensing piezoelectric geotechnical cable 7 via a data line 5, a data processing module connected to the self-sensing signal acquisition module 6 via a network, and a monitoring result output module connected to the data processing module via a network;

[0059] The self-sensing signal acquisition module 6 is used to collect and analyze the impedance signal and voltage signal of the self-sensing piezoelectric geotechnical cable 7, and send the impedance data and voltage data obtained by the analysis to the data processing module;

[0060] The data processing module calculates the three-dimensional deformation value of the self-sensing piezoelectric geotextile cable 7 according to the impedance data and voltage data sent by the self-sensing signal acquisition module 6, and sends the self-sensing piezoelectric geotextile cable 7 deformation warning and highway slope landslide warning to the monitoring result output module;

[0061] The monitoring result output module outputs the deformation warning of the self-sensing piezoelectric geotechnical cable 7 and the highway slope landslide warning sent by the data processing module.

[0062] Furthermore, the self-sensing piezoelectric geotechnical cable 7 includes a conductive core 2, a polyvinylidene fluoride piezoelectric film 3 wrapped around the outside of the conductive core 2, and an insulating protective sleeve 4 wrapped around the outside of the polyvinylidene fluoride piezoelectric film 3;

[0063] A plurality of conductive electrodes 1 are arranged on the inner surface of the polyvinylidene fluoride piezoelectric film 3 , and the conductive electrodes 1 are embedded in the surface of the conductive core 2 .

[0064] Preferably, the polyvinylidene fluoride piezoelectric film 3 is a 30 μm thick polyvinylidene fluoride (PVDF) manufactured using a film forming device and a constant temperature annealing device, stretched to about 4 times its original length by a temperature-controlled film stretching device, and polarized in the radial direction by a high-voltage polarization device.

[0065] Preferably, the diameter of the conductive core 2 is 1.3 mm, the thickness of the polyvinylidene fluoride piezoelectric film 3 is 30 μm, the thickness of the insulating protective sleeve 4 is 0.5 mm, and the diameter of the assembled self-sensing piezoelectric geotechnical cable 7 is 2.36 mm.

[0066] A plurality of conductive electrodes 1 are arranged on the inner surface of the polyvinylidene fluoride piezoelectric film 3 , and the conductive electrodes 1 are embedded in the surface of the conductive core 2 .

[0067] Furthermore, the conductive electrodes 1 are arrayed on the polyvinylidene fluoride piezoelectric film 3;

[0068] The conductive electrode 1 includes a positive conductive electrode 11 and a negative conductive electrode 12, and the positive conductive electrode 11 and the negative conductive electrode 12 are alternately arranged along the direction of the self-sensing piezoelectric geotechnical cable 7;

[0069] The conductive electrode 1 includes several groups of positive conductive modules and several groups of negative conductive modules;

[0070] Each group of positive conductive modules includes a plurality of positive conductive electrodes 11, and each group of positive conductive electrodes 11 is located on the same cross section of the self-sensing piezoelectric geotechnical cable 7;

[0071] Each group of negative conductive modules includes a plurality of negative conductive electrodes 12 , and each group of negative conductive electrodes 12 is located on the same cross section of the self-sensing piezoelectric geotechnical cable 7 .

[0072] Preferably, the conductive electrode 1 is made of metallic copper.

[0073] Preferably, the spacing between the conductive electrodes 1 is 15 mm, the thickness of the conductive electrode 1 is 0.1 mm, the width of the conductive electrode 1 is 0.6 mm, and the length of the conductive electrode 1 is 2 mm.

[0074] Preferably, the conductive electrodes 1 are arranged equidistantly on the polyvinylidene fluoride film 3 in an array arrangement, and the positive conductive electrodes 11 and the negative conductive electrodes 12 are arranged alternately along the direction of the self-sensing piezoelectric geocable 7 .

[0075] Preferably, the positive conductive module is the cross-section of the self-sensing piezoelectric geotextile cable 7 in which all positive conductive electrodes 11 are arranged, which can be called the positive cross-section; the negative conductive module is the cross-section of the self-sensing piezoelectric geotextile cable 7 in which all negative conductive electrodes 12 are arranged, which can be called the negative cross-section; in the self-sensing piezoelectric geotextile cable 7, the positive cross-section and the negative cross-section are arranged alternately.

[0076] Preferably, 16 positive conductive electrodes 11 are arranged on the positive cross section, and pairs of positive conductive electrodes 11 are symmetrical about the center of the positive cross section to form positive conductive electrode pairs, that is, 8 pairs of positive conductive electrode pairs symmetrical about the center of the positive cross section are arranged on the positive cross section. Later, we need to calculate the displacement of the polyvinylidene fluoride piezoelectric film 3 along the direction of the connection line of each pair of positive conductive electrode pairs, that is, calculate the displacement of the polyvinylidene fluoride piezoelectric film 3 along the direction of the connection line of the 8 pairs of positive conductive electrode pairs (8 directions).

[0077] Preferably, 16 negative conductive electrodes 12 are arranged on the negative cross section, and pairs of negative conductive electrodes 12 are symmetrical about the center of the negative cross section to form negative conductive electrode pairs, that is, 8 pairs of negative conductive electrode pairs symmetrical about the center of the negative cross section are arranged on the negative cross section. Later, we need to calculate the displacement of the polyvinylidene fluoride piezoelectric film 3 along the direction of the connection line of each pair of negative conductive electrodes, that is, calculate the displacement of the polyvinylidene fluoride piezoelectric film 3 along the direction of the connection line of the 8 pairs of negative conductive electrodes (8 directions).

[0078] Preferably, the method for calculating the displacement of the polyvinylidene fluoride piezoelectric film 3 along the direction of the connection between 8 pairs of positive / negative conductive electrodes (8 directions) is the same, regardless of the positive or negative of the conductive electrodes, and will be collectively referred to as calculating the displacement of the polyvinylidene fluoride piezoelectric film 3 along the direction of the connection between 8 pairs of conductive electrodes (8 directions) hereinafter.

[0079] Further, the self-sensing signal acquisition module 6 includes an impedance signal acquisition module and a voltage signal acquisition module;

[0080] The two ends of the impedance signal acquisition module are respectively connected to the adjacent positive conductive electrode 11 and negative conductive electrode 12;

[0081] Two ends of the voltage signal acquisition module are connected to the adjacent positive conductive electrode 11 and negative conductive electrode 12 respectively.

[0082] Preferably, the arrangement position of the positive conductive electrode 11 on the positive cross section is the same as the arrangement position of the negative conductive electrode 12 on the negative cross section.

[0083] Preferably, on the adjacent positive cross-section and negative cross-section, one end of the impedance signal acquisition module is connected to the positive conductive electrode on the positive cross-section, and the other end is connected to the negative conductive electrode on the negative cross-section that is closest to the positive conductive electrode, so as to collect the impedance signal between the adjacent positive conductive electrode and the negative conductive electrode; one end of the voltage signal acquisition module is connected to the positive conductive electrode on the positive cross-section, and the other end is connected to the negative conductive electrode on the negative cross-section that is closest to the positive conductive electrode, so as to collect the voltage signal between the adjacent positive conductive electrode and the negative conductive electrode.

[0084] Furthermore, the impedance signal acquisition module is an impedance meter, and the voltage signal acquisition unit is an oscilloscope.

[0085] Preferably, when the sensing piezoelectric geotextile cable 7 changes due to external force or deformation, the impedance meter will accurately collect the impedance value between the adjacent positive conductive electrode 11 and the negative conductive electrode 12 on the polyvinylidene fluoride piezoelectric film 3, and output impedance signals for different strains of the polyvinylidene fluoride piezoelectric film 3. The change in the impedance value between the adjacent positive conductive electrode 11 and the negative conductive electrode 12 on the polyvinylidene fluoride piezoelectric film 3 is directly related to the strain of the polyvinylidene fluoride piezoelectric film 3, that is, the impedance meter can output corresponding impedance signals for the strain of the polyvinylidene fluoride piezoelectric film 3.

[0086] Preferably, when the self-sensing piezoelectric geotextile cable 7 changes due to external force or deformation, a voltage change will occur between the adjacent positive conductive electrodes 11 and negative conductive electrodes 12 on the polyvinylidene fluoride piezoelectric film 3, and the oscilloscope will accurately collect the peak and valley values ​​of these voltage signals to monitor the deformation of the self-sensing piezoelectric geotextile cable 7.

[0087] Reference Figures 3-7 As shown, a highway facility safety monitoring method based on self-sensing geotechnical cable includes the following steps:

[0088] S1. When the road slope deforms, the self-sensing piezoelectric geotextile cable 7 is mechanically deformed due to mechanical force;

[0089] S2, the self-sensing piezoelectric geotextile cable 7 after mechanical deformation will generate impedance signal and voltage signal;

[0090] S3. The self-sensing signal acquisition module 6 acquires and analyzes the impedance signal and voltage signal of the self-sensing piezoelectric geotechnical cable 7, and sends the analyzed impedance data and voltage data to the data processing module;

[0091] S4. The data processing module calculates the three-dimensional deformation value of the self-sensing piezoelectric geotechnical cable 7 according to the impedance data and voltage data sent by the self-sensing signal acquisition module 6, and sends the deformation warning of the self-sensing piezoelectric geotechnical cable 7 and the landslide warning of the highway slope to the monitoring result output module;

[0092] S5. The monitoring result output module outputs the deformation warning of the self-sensing piezoelectric geotechnical cable 7 and the landslide warning of the highway slope;

[0093] In the step S2, the principles for generating the impedance signal and voltage signal are as follows:

[0094] Based on the piezoelectric effect, when the polyvinylidene fluoride piezoelectric film 3 in the self-sensing geotechnical cable 7 is subjected to a mechanical force, on the one hand, the positive and negative charges inside the polyvinylidene fluoride piezoelectric film 3 will have a relative displacement, thereby generating a voltage signal. On the other hand, the impedance characteristic of the polyvinylidene fluoride piezoelectric film 3 will also change due to the mechanical force, thereby generating an impedance signal.

[0095] Furthermore, the step S3 specifically includes the following steps:

[0096] S31. The impedance signal acquisition module acquires the impedance signal between the adjacent positive conductive electrode 11 and negative conductive electrode 12, calculates the normalized impedance of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and negative conductive electrode 12 according to the impedance signal, and sends the normalized impedance to the data processing module.

[0097] S32. The voltage signal acquisition module acquires the voltage signal between the adjacent positive conductive electrode 11 and negative conductive electrode 12, calculates the peak voltage and effective value voltage of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and negative conductive electrode 12 according to the voltage signal, and sends the peak voltage and effective value voltage to the data processing module.

[0098] Preferably, because the initial impedance of the polyvinylidene fluoride piezoelectric film 3 is different in different cases, the impedance of the polyvinylidene fluoride piezoelectric film 3 is normalized, and the normalized impedance formula is as shown in Formula 1.

[0099] Preferably, because the initial impedance of the polyvinylidene fluoride piezoelectric film 3 is different in different cases, the impedance of the polyvinylidene fluoride piezoelectric film 3 is normalized, and the normalized impedance formula is as shown in Formula 1.

[0100]

[0101] Where K Z is the normalized impedance of the polyvinylidene fluoride piezoelectric film 3, Z s is the impedance value collected by the impedance signal collection module between the adjacent positive conductive electrode 11 and the negative conductive electrode 12 during the stretching process, Z 0 It is the initial impedance value collected by the impedance signal collection module between the adjacent positive conductive electrode 11 and the negative conductive electrode 12 .

[0102] Furthermore, step S4 specifically includes the following steps:

[0103] S41, the data processing module calculates the three-dimensional deformation value of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and the negative conductive electrode 12 according to the received normalized impedance, and when the three-dimensional deformation value reaches or exceeds the three-dimensional deformation threshold preset by the system, the deformation warning of the self-sensing geotextile cable 7 is sent to the monitoring result output module;

[0104] The three-dimensional deformation value of the polyvinylidene fluoride piezoelectric film 3 includes: the strain value, vertical displacement value, and shear displacement value of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and the negative conductive electrode 12. The vertical displacement value refers to the displacement of the polyvinylidene fluoride piezoelectric film 3 in the direction of the connection line of two conductive electrodes 1 symmetrical about the axis center on the same cross section of the self-sensing geotechnical cable 7;

[0105] The deformation warning of the self-sensing geotechnical cable 7 includes the warning of the self-sensing geotechnical cable 7 strain exceeding the threshold value, the warning of the self-sensing geotechnical cable 7 vertical displacement exceeding the threshold value, and the warning of the self-sensing geotechnical cable 7 shear displacement exceeding the threshold value;

[0106] S42, the data processing module determines whether a landslide occurs on the highway slope according to the received peak voltage and effective value voltage, and sends a highway slope landslide warning to the monitoring result output module when a landslide occurs on the highway slope.

[0107] Preferably, the data processing module includes a strain-normalized impedance data processing module, a vertical displacement-normalized impedance data processing module, a shear displacement-impedance data processing module, and a voltage data processing module, as described in detail as follows:

[0108] (1) Strain-normalized impedance data processing module:

[0109] The strain value of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and the negative conductive electrode 12 can be calculated based on the received normalized impedance of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and the negative conductive electrode 12, and when the strain value of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and the negative conductive electrode 12 reaches or exceeds the strain threshold value preset by the system, the self-sensing geotextile cable 7 strain exceeding threshold value warning is sent to the monitoring result output module.

[0110] Reference Figure 4 As shown, based on the strain-normalized impedance mathematical model of the polyvinylidene fluoride piezoelectric film 3 established in the indoor test, the polyvinylidene fluoride piezoelectric film 3 was subjected to two tensile tests, and the mathematical model of the strain-normalized impedance of the polyvinylidene fluoride piezoelectric film 3 was established using the double exponential function model, as shown in Formula 2.

[0111]

[0112] In the formula, the correlation coefficient R 2 They are 0.99309 and 0.99958 respectively.

[0113] Using the above-mentioned strain-normalized impedance mathematical model, the strain-normalized impedance data processing module can calculate the strain value of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and the negative conductive electrode 12, and compare it with the strain threshold preset by the system. If the strain value of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and the negative conductive electrode 12 reaches or exceeds the strain threshold preset by the system, the strain exceeding threshold warning of the self-sensing geotextile cable 7 is sent to the monitoring result output module.

[0114] (2) Vertical displacement-normalized impedance data processing module:

[0115] The vertical displacement value of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and the negative conductive electrode 12 can be calculated based on the received normalized impedance of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and the negative conductive electrode 12, and when the vertical displacement value of the polyvinylidene fluoride piezoelectric film 3 at the conductive electrode reaches or exceeds the vertical displacement threshold preset by the system, the vertical displacement exceeding threshold warning of the self-sensing geotextile cable 7 is sent to the monitoring result output module.

[0116] The vertical displacement value of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrodes 11 and the negative conductive electrodes 12 refers to the displacement of the polyvinylidene fluoride piezoelectric film 3 along the direction of the connection of 8 pairs of conductive electrodes on the cross section of the self-sensing geotextile cable 7 (8 directions), that is, the displacement along the direction of the connection of 8 pairs of conductive electrodes (8 directions perpendicular to the self-sensing geotextile cable 7).

[0117] Reference Figure 5 As shown, the vertical displacement-normalized impedance data processing module calculates the vertical displacement value of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and the negative conductive electrode 12 according to the received normalized impedance of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and the negative conductive electrode 12, and the calculation formula is as follows:

[0118] N 1 =2R 1 θ

[0119] N 2 =2R 2 θ

[0120] R 2 -R 1 =d (3)

[0121]

[0122] N 2 -N 1 =2εL (7)

[0123]

[0124] Among them, N 1 is the length between the two conductive electrodes on the compression surface of the self-sensing geotextile cable 7, R 1 is the radius of curvature between the positive conductive electrode and the negative conductive electrode adjacent to the compression surface of the self-sensing geotextile cable 7, N 2 is the length between the positive conductive electrode and the negative conductive electrode adjacent to the tensile surface of the self-sensing geotextile cable 7, R 2 is the radius of curvature between the positive conductive electrode and the negative conductive electrode adjacent to the tensile surface of the self-sensing geotextile cable 7, θ is the deformation angle of the self-sensing geotextile cable 7, and θ i is the deformation angle of the self-sensing geotextile cable 7 at the cross section i, θ i-1 is the deformation angle of the self-sensing geotextile cable 7 at the cross section i-1, L is the initial length of the bending unit of the self-sensing geotextile cable 7, d is the diameter of the self-sensing geotextile cable 7, ε is the strain value of the polyvinylidene fluoride piezoelectric film 3, where △L is the spacing between the electrodes, ε i-1 is the strain value of the polyvinylidene fluoride piezoelectric film 3 at the cross section i-1, Di is the deformation of the polyvinylidene fluoride piezoelectric film 3 at the cross section i, that is, D i is the displacement value of the polyvinylidene fluoride piezoelectric film 3 along the connecting line direction of the conductive electrode pair i.

[0125] The vertical displacement-normalized impedance data processing module calculates the vertical displacement value of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode and the negative conductive electrode, and compares it with the vertical displacement threshold preset by the system. If the vertical displacement value of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode and the negative conductive electrode reaches or exceeds the vertical displacement threshold preset by the system, the vertical displacement exceeding threshold warning of the self-sensing geotextile cable 7 is sent to the monitoring result output module.

[0126] (3) Shear displacement-impedance data processing module:

[0127] The shear displacement value of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and the negative conductive electrode 12 can be calculated based on the received normalized impedance of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and the negative conductive electrode 12, and when the shear displacement value of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and the negative conductive electrode 12 reaches or exceeds the shear displacement threshold preset by the system, the shear displacement exceeding threshold warning of the self-sensing geotextile cable 7 is sent to the monitoring result output module.

[0128] Based on the analysis of indoor test data, the size of the normalized impedance is mainly related to the force and deformation of the polyvinylidene fluoride piezoelectric film 3, presenting a bilinear model. As shown in Formula 10, a shear displacement-normalized impedance mathematical model of the polyvinylidene fluoride piezoelectric film 3 is established.

[0129]

[0130] Where: Ds is the shear displacement; a 1 , b 1 , a 2 , b 2 are the monotonic shear impedance coefficients, which are related to the polyvinylidene fluoride piezoelectric film 3, soil material properties, and the stress field and displacement rate field to which the polyvinylidene fluoride piezoelectric film 3 is subjected; c is the shear displacement corresponding to the inflection point of the normalized impedance drop rate, and this value is related to the soil strain softening point.

[0131] Based on the indoor test data, the shear displacement-normalized resistance curve was regressed and analyzed. Figure 6 shown.

[0132] Using the above-mentioned shear displacement-normalized impedance mathematical model, the shear displacement-impedance data processing module can calculate the shear displacement value of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and the negative conductive electrode 12, and compare it with the shear displacement threshold preset by the system. If the shear displacement value of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and the negative conductive electrode 12 reaches or exceeds the shear displacement threshold preset by the system, the shear displacement exceeding threshold warning of the self-sensing geotextile cable 7 is sent to the monitoring result output module.

[0133] (4) Voltage data processing module:

[0134] According to the analysis of the voltage characteristics of the polyvinylidene fluoride piezoelectric film 3 between the adjacent positive conductive electrode 11 and the negative conductive electrode 12, when a landslide occurs on the highway slope, a highway slope landslide warning is sent to the monitoring result output module.

[0135] Reference Figure 6 The shear displacement-voltage curve of the polyvinylidene fluoride piezoelectric film 3 at the conductive electrode shown in the figure shows that before and after the shearing starts, the voltage is only a straight line near the zero point. When the normal stress is 150 kPa and 200 kPa, the voltage reaches a maximum peak of 226.01 mV at the same time when the polyvinylidene fluoride piezoelectric film 3 breaks, and then the real-time voltage returns to zero. In this case, the voltage data processing module sends the highway slope landslide warning to the monitoring result output module.

[0136] Furthermore, the monitoring result output module outputs the received self-sensing geotechnical cable 7 deformation warning and highway slope landslide warning.

[0137] Preferably, the monitoring result output module outputs the received self-sensing geotextile cable 7 strain exceeding threshold warning, self-sensing geotextile cable 7 vertical displacement exceeding threshold warning, self-sensing geotextile cable 7 shear displacement exceeding threshold warning, and highway slope landslide warning accordingly.

[0138] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A highway facility safety monitoring device based on self-sensing geotechnical cable, characterized in that: It comprises a self-sensing piezoelectric geotechnical cable (7) laid inside a highway slope, a self-sensing signal acquisition module (6) connected to the self-sensing piezoelectric geotechnical cable (7) via a data line (5), a data processing module connected to the self-sensing signal acquisition module (6) via a network, and a monitoring result output module connected to the data processing module via a network; The self-sensing signal acquisition module (6) is used to collect and analyze the impedance signal and voltage signal of the self-sensing piezoelectric geotechnical cable (7), and send the impedance data and voltage data obtained by analysis to the data processing module; The data processing module calculates the three-dimensional deformation value of the self-sensing piezoelectric geotextile cable (7) according to the impedance data and the voltage data sent by the self-sensing signal acquisition module (6), and sends the deformation warning of the self-sensing piezoelectric geotextile cable (7) and the highway slope landslide warning to the monitoring result output module; The monitoring result output module outputs the deformation warning of the self-sensing piezoelectric geotechnical cable (7) and the highway slope landslide warning sent by the data processing module.

2. A highway facility safety monitoring device based on a self-sensing geotechnical cable according to claim 1, characterized in that: The self-sensing piezoelectric geotechnical cable (7) comprises a conductive core (2), a polyvinylidene fluoride piezoelectric film (3) wrapped around the outside of the conductive core (2), and an insulating protective sleeve (4) wrapped around the outside of the polyvinylidene fluoride piezoelectric film (3); A plurality of conductive electrodes (1) are arranged on the inner surface of the polyvinylidene fluoride piezoelectric film (3), and the conductive electrodes (1) are embedded in the surface of the conductive core (2).

3. A highway facility safety monitoring device based on a self-sensing geotechnical cable according to claim 2, characterized in that: The conductive electrodes (1) are arrayed on the polyvinylidene fluoride piezoelectric film (3); The conductive electrode (1) comprises a positive conductive electrode (11) and a negative conductive electrode (12), and the positive conductive electrode (11) and the negative conductive electrode (12) are arranged alternately along the direction of the self-sensing piezoelectric geotechnical cable (7); The conductive electrode (1) comprises a plurality of groups of positive conductive modules and a plurality of groups of negative conductive modules; Each group of the positive conductive modules comprises a plurality of the positive conductive electrodes (11), and each group of the positive conductive electrodes (11) is located on the same cross section of the self-sensing piezoelectric geotechnical cable (7); Each group of the negative conductive modules includes a plurality of the negative conductive electrodes (12), and each group of the negative conductive electrodes (12) is located on the same cross section of the self-sensing piezoelectric geotechnical cable (7).

4. A highway facility safety monitoring device based on a self-sensing geotechnical cable according to claim 3, characterized in that: The self-sensing signal acquisition module (6) comprises an impedance signal acquisition module and a voltage signal acquisition module; Two ends of the impedance signal acquisition module are respectively connected to the adjacent positive conductive electrode (11) and the negative conductive electrode (12); Two ends of the voltage signal acquisition module are respectively connected to the adjacent positive conductive electrode (11) and the negative conductive electrode (12).

5. A highway facility safety monitoring device based on a self-sensing geotechnical cable according to claim 4, characterized in that: The impedance signal acquisition module is an impedance meter, and the voltage signal acquisition unit is an oscilloscope.

6. A highway facility safety monitoring method based on a self-sensing geotechnical cable according to claim 5, comprising the following steps: S1. When the road slope is deformed, the self-sensing piezoelectric geotextile cable (7) is mechanically deformed due to mechanical force; S2, the self-sensing piezoelectric geotextile cable (7) after mechanical deformation generates an impedance signal and a voltage signal; S3, the self-sensing signal acquisition module (6) acquires and analyzes the impedance signal and the voltage signal of the self-sensing piezoelectric geotechnical cable (7), and sends the impedance data and the voltage data obtained by the analysis to the data processing module; S4, the data processing module calculates the three-dimensional deformation value of the self-sensing piezoelectric geotextile cable (7) according to the impedance data and the voltage data sent by the self-sensing signal acquisition module (6), and sends the deformation warning of the self-sensing piezoelectric geotextile cable (7) and the highway slope landslide warning to the monitoring result output module; S5, the monitoring result output module outputs the deformation warning of the self-sensing piezoelectric geotechnical cable (7) and the highway slope landslide warning sent by the data processing module; In step S2, the principle of generating the impedance signal and the voltage signal is as follows: Based on the piezoelectric effect, when the polyvinylidene fluoride piezoelectric film (3) in the self-sensing geotextile cable (7) is subjected to mechanical force, on the one hand, the positive and negative charges inside the polyvinylidene fluoride piezoelectric film (3) will undergo relative displacement, thereby generating a voltage signal; on the other hand, the impedance characteristics of the polyvinylidene fluoride piezoelectric film (3) will also change due to the mechanical force, thereby generating an impedance signal.

7. According to the method for highway facility safety monitoring based on self-sensing geotextile cable according to claim 6, the step S3 specifically comprises the following steps: S31, the impedance signal acquisition module acquires the impedance signal between the adjacent positive conductive electrode (11) and the negative conductive electrode (12), and calculates the normalized impedance of the polyvinylidene fluoride piezoelectric film (3) between the adjacent positive conductive electrode (11) and the negative conductive electrode (12) based on the impedance signal, and sends the normalized impedance to the data processing module. S32, the voltage signal acquisition module acquires the voltage signal between the adjacent positive conductive electrode (11) and the negative conductive electrode (12), and calculates the peak voltage and the effective value voltage of the polyvinylidene fluoride piezoelectric film (3) between the adjacent positive conductive electrode (11) and the negative conductive electrode (12) according to the voltage signal, and sends the peak voltage and the effective value voltage to the data processing module.

8. A highway facility safety monitoring method based on self-sensing geotechnical cable according to claim 7, characterized in that: The step S4 specifically comprises the following steps: S41, the data processing module calculates the three-dimensional deformation value of the polyvinylidene fluoride piezoelectric film (3) between the adjacent positive conductive electrode (11) and the negative conductive electrode (12) according to the received normalized impedance, and when the three-dimensional deformation value reaches or exceeds the three-dimensional deformation threshold preset by the system, sends the deformation warning of the self-sensing geotextile cable (7) to the monitoring result output module; The three-dimensional deformation value of the polyvinylidene fluoride piezoelectric film (3) includes: the strain value, vertical displacement value, and shear displacement value of the polyvinylidene fluoride piezoelectric film (3) between the adjacent positive conductive electrode (11) and the negative conductive electrode (12); the vertical displacement value refers to the displacement of the polyvinylidene fluoride piezoelectric film (3) in the direction of the connection line between two conductive electrodes (1) symmetrical about the axis center on the same cross section of the self-sensing geotechnical cable (7); The deformation warning of the self-sensing geotextile cable (7) includes a warning of the self-sensing geotextile cable (7) strain exceeding a threshold value, a warning of the self-sensing geotextile cable (7) vertical displacement exceeding a threshold value, and a warning of the self-sensing geotextile cable (7) shear displacement exceeding a threshold value; S42, the data processing module determines whether a landslide occurs on the highway slope according to the received peak voltage and the effective value voltage, and sends a highway slope landslide warning to the monitoring result output module when a landslide occurs on the highway slope.

9. A highway facility safety monitoring method based on self-sensing geotechnical cable according to claim 8, characterized in that: The monitoring result output module outputs the received deformation warning of the self-sensing geotechnical cable (7) and the highway slope landslide warning.

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