A distributed intelligent monitoring device and method for the whole process of roadbed slope disaster

Abstract

The present invention discloses a distributed intelligent monitoring device and method for the whole process of roadbed slope disaster, which relates to the technical field of monitoring devices for civil engineering. The monitoring device includes a roadbed slope deformation sensing material unit, which includes a geotechnical reinforcement belt layer, a flexible conductive polymer film layer and a stretchable flexible circuit film layer arranged in sequence in a protective shell; a plurality of the roadbed slope deformation sensing material units are woven into a network to form an intelligent sensing geogrid for roadbed slope deformation; the present invention can realize distributed deformation monitoring of the whole process of landslide disasters in roadbed and slope engineering, and can prevent road cracking and improve roadbed stability. In addition to playing a role in the field of landslide disaster monitoring in roadbed and slope engineering, the present invention also has application potential in the fields of road cracking monitoring, ground settlement monitoring and differential deformation monitoring of renovated and expanded roads.

Description

Technical Field

[0001] The present invention relates to the technical field of monitoring devices for civil engineering, and in particular to a distributed intelligent monitoring device and method for the entire process of roadbed slope disaster. Background Art

[0002] Modern transportation infrastructure such as highways has a high speed and a large traffic volume. Once disasters such as landslides, collapses and collapses occur, it is difficult for high-speed traffic to evacuate, which can easily cause heavy casualties and huge property losses. At present, the monitoring and early warning of roadbed and slope engineering mainly focus on external deformation indicators such as settlement and horizontal displacement of certain discrete points. However, practice shows that roadbed slope damage is usually a progressive damage from the inside to the outside. Only when the damage state inside the roadbed slope develops to a certain extent, the external differential settlement will change significantly, which often leads to the miss of the best reinforcement opportunity. In order to overcome this problem, researchers began to strengthen the field testing and research of internal deformation indicators of roadbed slopes. However, the current monitoring of internal deformation of roadbed slopes mainly relies on non-distributed measurement methods, such as strain gauges, flexible tensiometers, fiber grating sensors, etc. These methods have obvious limitations when monitoring the damage of roadbed slopes between two sensors. In recent years, distributed optical fiber technology based on Brillouin scattering has gradually emerged. This type of technology has many advantages such as high monitoring accuracy, long sensing distance, and no electromagnetic interference. However, its fiber optic distributed strain measurement range is usually less than 2%, which makes it difficult to perceive the entire process of roadbed slope disasters (maximum strain up to 15%). In addition, there are problems such as expensive demodulators and easy damage of optical fiber materials, which restrict the large-scale application of this technology in distributed deformation monitoring of roadbed slopes throughout their life cycle.

[0003] In recent years, geosynthetics (such as geogrids, etc.) reinforced soil structures have been widely used in roadbed engineering and slope engineering. However, traditional geosynthetics only have the function of roadbed slope reinforcement and cannot sense the distributed deformation inside the roadbed slope. At present, the existing technology has prepared intelligent geosynthetics with both deformation sensing and roadbed slope reinforcement functions based on the tensile effect of conductive polymers, and further combined with distributed resistance acquisition technology and packaging technology to develop distributed roadbed slope deformation intelligent monitoring devices. However, the conductive polymer-based intelligent geosynthetics in the above-mentioned distributed roadbed slope deformation intelligent monitoring device are prepared using a single-dimensional conductive filler (i.e., zero-dimensional carbon black) and melt blending technology. In order to achieve the strongest tensile effect, it is often necessary to add a large amount of conductive filler to the polymer matrix. A high amount of conductive filler added will not only destroy the inherent good ductility of the polymer matrix, reduce its toughness and reduce the strain measurement range of the conductive polymer, but also the high viscosity of the polymer matrix in the molten state is not conducive to the uniform dispersion of the conductive filler, and easily cause micro-agglomeration of the conductive filler, thereby reducing the measurement accuracy and linear range of the distributed intelligent monitoring device for roadbed slope deformation. In the field of civil engineering, this will result in the inability of the distributed intelligent monitoring device for roadbed slope deformation to accurately monitor and provide safety warnings for the entire process of roadbed slope disasters. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a distributed intelligent monitoring device and method for the entire process of roadbed slope disasters, which has the functions of large deformation sensing and roadbed slope reinforcement. In roadbed projects, distributed deformation monitoring of the entire process of roadbed slope disasters can be realized, and at the same time, road surface cracking can be prevented and roadbed stability can be improved.

[0005] The technical solution of the present invention is as follows:

[0006] In a first aspect of the present invention, a distributed intelligent monitoring device for the entire process of roadbed slope disaster is provided, including a roadbed slope deformation sensing material unit, wherein the roadbed slope deformation sensing material unit includes a geotechnical reinforcement belt layer, a flexible conductive polymer film layer, and a stretchable flexible circuit film layer sequentially arranged in a protective shell; a plurality of the roadbed slope deformation sensing material units are woven in warp and weft directions to form an intelligent geogrid for sensing roadbed slope deformation;

[0007] Measuring point electrodes are arranged at multiple set positions of the stretchable flexible circuit film layer, each measuring point electrode is led to the end of the stretchable flexible circuit film layer through a wire, the measuring point electrode measures the resistance of the flexible conductive polymer film layer and outputs the signal through the wire.

[0008] The intelligent sensing geogrid for roadbed slope deformation can not only play the role of roadbed slope reinforcement, but also realize distributed deformation monitoring of the whole process of roadbed slope disaster in projects such as roadbed and slope. In addition, by setting a flexible conductive polymer film layer and a stretchable flexible circuit film layer on the geotechnical reinforcement belt layer, the problem of reduced tensile performance of the geotechnical reinforcement belt layer due to high content of conductive filler and its uneven dispersion in the geotechnical reinforcement belt layer can be avoided, thereby improving the measurement range and perception accuracy of the intelligent monitoring device for roadbed slope deformation.

[0009] In a second aspect of the present invention, a method for preparing a distributed intelligent monitoring device for the entire process of roadbed slope disaster is provided, comprising the following steps:

[0010] preparing a geotechnical reinforcement tape layer;

[0011] A composite conductive material made of nanomaterials of different dimensions is added to a polymer matrix solution, and an ultrasonic dispersion treatment is performed to form a conductive ink, and the conductive ink is applied to a geotechnical reinforcement tape layer to form a flexible conductive polymer film layer;

[0012] Setting measuring point electrodes and conducting wires on a flexible polymer substrate film to obtain a stretchable flexible circuit film layer;

[0013] Pasting the stretchable flexible circuit film layer on the flexible conductive polymer film layer, and connecting the measuring point electrodes to the flexible conductive polymer film layer;

[0014] The geotechnical reinforcement belt layer, the flexible conductive polymer film layer and the stretchable flexible circuit film layer are encapsulated to obtain a roadbed slope deformation sensing material unit;

[0015] A plurality of the roadbed slope deformation sensing material units are woven into a network in the warp and weft directions to obtain a roadbed slope deformation intelligent sensing geogrid.

[0016] In a third aspect of the present invention, a distributed monitoring method for the entire process of roadbed slope disaster is proposed, which is implemented by using the intelligent monitoring device of the first aspect, and the specific steps are as follows:

[0017] The intelligent sensing geogrid for roadbed slope deformation is buried inside the roadbed slope, and the wires led out from the intelligent sensing geogrid for roadbed slope deformation are connected to a multi-channel resistance acquisition device. The resistance of the flexible conductive polymer film layer is collected through the multi-channel resistance acquisition device and the roadbed slope deformation data is output.

[0018] One or more technical solutions of the present invention have the following beneficial effects:

[0019] (1) The roadbed slope deformation sensing material unit provided by the present invention uses a geotextile reinforcement tape as a base layer. The geotextile reinforcement tape needs to have good mechanical properties and a certain stiffness so as to play the role of roadbed slope reinforcement. A flexible conductive polymer film is used as a conductive layer. The flexible conductive polymer film has good sensing performance and tensile sensitivity, and its tensile stiffness is very small, so it can deform synergistically with the geotextile reinforcement tape. A stretchable flexible circuit film is used as a sensing layer to realize the transmission of electrical signals during the stretching process. Through the cooperation of the flexible conductive polymer film and the stretchable flexible circuit film, distributed deformation monitoring of the entire process of roadbed slope disaster is realized.

[0020] (2) The roadbed slope deformation sensing material unit provided by the present invention uses a heat shrink tube as an external protective shell, which can ensure that the intelligent sensing material is not disturbed by external moisture and acid-base media throughout its life cycle and has good tensile properties. At the same time, the heat shrink tube adopts a double-layer structure with an outer layer made of polyolefin material and an inner layer made of flexible hot-melt adhesive. The hot-melt adhesive in the inner layer can be melted by heating to tightly bond with the base of the intelligent sensing material, so that it can deform synergistically with the base material, thereby improving the measurement accuracy.

[0021] (3) The roadbed slope deformation sensing material unit provided by the present invention is woven into a network in the warp and weft directions, and the nodes are formed by a secondary injection molding process to obtain a roadbed slope deformation intelligent sensing geogrid. The roadbed slope deformation intelligent sensing geogrid is used as a distributed roadbed slope disaster full-process intelligent monitoring device to realize distributed monitoring of the deformation of the roadbed slope disaster full-process.

[0022] (4) The roadbed slope deformation sensing material unit provided by the present invention separates the conductive polymer film layer, the signal transmission layer and the geotechnical reinforcement belt base layer, and adopts a solution blending method to prepare the conductive polymer film, which can ensure that the conductive network structure in the intelligent sensing material is evenly distributed in the polymer, and can also avoid reducing the toughness of the geotechnical reinforcement belt base layer due to the large amount of conductive filler added.

[0023] (5) In the flexible conductive polymer film of the present invention, the conductive filler is synergistically prepared using carbon nanomaterials of different dimensions, and the composite conductive material and the polymer matrix solution are evenly mixed through ultrasonic dispersion treatment, which is conducive to forming a more uniform and stable conductive network. Compared with the conductive polymers prepared from existing single-dimensional nanomaterials, its accuracy, sensitivity and linearity are significantly improved, and high-precision measurement of deformation of the entire process of roadbed slope disaster can be achieved.

[0024] (6) In the flexible conductive polymer film of the present invention, measuring point electrodes and nano silver particle conductors are printed on the flexible polymer matrix film to form a flexible printed circuit board as a signal transmission layer. Compared with the existing copper core plastic wires, the flexible printed circuit board has very small tensile stiffness and a limit tensile strain much larger than that of the geotechnical reinforcement tape, and will not break or come off, thus avoiding failure of the measuring circuit and ensuring the continuity and effectiveness of the output signal of the monitoring of the entire process of the roadbed slope disaster.

[0025] (7) In the flexible conductive polymer film of the present invention, the flexible printed circuit board can detect the resistance change of the conductive polymer film in real time. During the measurement process, a measurement technology that can eliminate the influence of circuit resistance (for example, a bridge method, a four-lead method, etc.) is used to avoid the influence of wire resistance on the output signal, thereby further improving the measurement accuracy of the monitoring device.

[0026] (8) In addition to being able to play a role in landslide disaster monitoring in roadbed and slope engineering, the intelligent monitoring device of the present invention also has application potential in the fields of road crack monitoring, ground subsidence monitoring, and differential deformation monitoring of road reconstruction and expansion. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the roadbed slope deformation sensing material unit of Example 1;

[0028] Figure 2 is a schematic diagram of a stretchable flexible circuit film of Example 1;

[0029] Figure 3 It is a cross-sectional schematic diagram of a roadbed slope deformation sensing material unit of Example 1;

[0030] Figure 4 Schematic diagram of the intelligent sensing geogrid for roadbed slope deformation in Example 1;

[0031] Figure 5 This is a flow chart for preparing the flexible conductive polymer film of Example 2;

[0032] Figure 6 It is an intelligent sensing geogrid mechanical and electrical performance testing device;

[0033] Figure 7 This is the principle diagram of the four-wire collection resistor of the multi-channel collection device;

[0034] Figure 8 This is a schematic diagram of on-site intelligent monitoring of roadbed slope deformation in Example 3.

[0035] In the figure: 1. Stretchable flexible circuit film layer; 2. Flexible conductive polymer film layer; 3. Geotechnical reinforcement tape layer; 4. Flexible polymer matrix film; 5. Nanosilver particle wire; 6. Measuring point electrode; 7. Ink nozzle; 8. Ordinary strip; 9. Roadbed slope deformation sensing material unit; 10. Injection molding node; 11. Conductive contact piece; 12. Protective shell; 13. High and low temperature universal testing machine; 14. Environmental chamber; 15. Refrigeration device; 16. Heating device; 17. Multimeter; 18. Computer; 19. Fixture; 20. Roadbed slope deformation intelligent sensing geogrid; 21. Guide piece; 22. Multi-channel resistance acquisition equipment; 23. Roadbed. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0037] Example 1

[0038] In a typical embodiment of the present invention, a distributed intelligent monitoring device for the entire process of roadbed slope disaster is proposed. Figure 1-Figure 4 As shown, it includes a roadbed slope deformation sensing material unit 9, which includes a geotechnical reinforcement belt layer 3, a flexible conductive polymer film layer 2 and a stretchable flexible circuit film layer 1 arranged in sequence in a protective shell 12; a plurality of the roadbed slope deformation sensing material units 9 are woven in the warp and weft directions to form a roadbed slope deformation intelligent sensing geogrid 20; a plurality of set positions of the stretchable flexible circuit film layer 1 are provided with measuring point electrodes 6, each measuring point electrode 6 is led to the end of the stretchable flexible circuit film layer 1 through a wire, and the measuring point electrode 6 measures the resistance of the flexible conductive polymer film layer 2 and outputs the signal through the wire. Furthermore, the measuring point electrode 6 is attached to the upper surface of the flexible conductive polymer film layer 2, and the tensile strain distributed on the flexible conductive polymer film layer 2 is obtained according to the initial resistance and resistance change rate obtained by each measuring point electrode 6.

[0039] Specifically, the geotechnical reinforcement belt layer 3 is made of a polymer material with a thickness of 1.5 to 2.5 mm; the polymer material can be high-density polyethylene, polyvinyl chloride and polypropylene resin, etc. The geotechnical reinforcement belt layer 3 needs to have good mechanical properties and a certain rigidity. The geotechnical reinforcement belt layer 3 can be set to reinforce the roadbed slope.

[0040] In this embodiment, the stretchable flexible circuit film layer 1 is made of a polymer matrix, and a composite conductive material is added to the polymer matrix, and its thickness is 0.03~0.05mm; the composite conductive material is made of nanomaterials of different dimensions, and the polymer matrix can be polyurethane or polydimethylsiloxane; the nanomaterial includes at least one of one-dimensional carbon nanotubes (CNT) and two-dimensional graphene (GN), and zero-dimensional carbon black (CB). Nanomaterials of different dimensions can be selected to prepare different types of composite conductive fillers, for example, CB-CNT, CB-GN, CB-CNT-GN, etc.

[0041] The flexible conductive polymer film has a tensile-sensitive effect, that is, its resistivity increases with the increase of tensile strain, and the intelligent sensing grid resistivity-tensile strain constitutive model can be obtained by conducting an intelligent sensing geogrid tensile-sensitive test.

[0042] The flexible conductive polymer film is formed by coating conductive ink on the geotechnical reinforcement tape by a coating method (including screen printing, spray coating, spin coating, etc.) to form a flexible conductive polymer film layer 2 on the geotechnical reinforcement tape layer.

[0043] like Figure 2 As shown, the stretchable flexible circuit film layer 1 adopts a flexible polymer matrix film 4, and a nanosilver particle composite conductive ink is printed on the flexible polymer matrix film 4 through an ink nozzle 7 to form a measuring point electrode 6 and a nanosilver particle wire 5. The measuring point electrode 6 and the wire layer are sprayed with flexible insulating ink to achieve insulation. Copper core plastic wires are commonly used intelligent sensing material transmission circuit wires. However, the tensile performance of copper core plastic wires is poor and the rigidity is large. When they are stretched and deformed with the intelligent sensing reinforcement material, they are easily broken or detached at the measuring electrode, resulting in failure of the measurement circuit, which cannot meet the needs of large deformation monitoring of intelligent sensing reinforcement materials. However, this embodiment uses nanosilver particle wires 5 as transmission circuit wires, which have very small tensile stiffness and the ultimate tensile strain is much greater than that of geotechnical reinforcement tapes. Phenomena such as breaking and detaching will not occur, thus avoiding the failure of the measurement circuit.

[0044] Furthermore, the thickness of the flexible polymer matrix film 4 is 0.02-0.05 mm; the thickness of the flexible insulating ink layer is less than 0.02 mm, ensuring that its tensile stiffness is small enough to achieve coordinated deformation of the stretchable flexible circuit film layer with the bottom substrate during deformation.

[0045] In this embodiment, the stretchable flexible circuit film layer 1 and the flexible conductive polymer film layer 2 are pasted with flexible glue. The stretchable flexible circuit film layer 1 is provided with a window at the position where the measuring point electrode 6 is set. The measuring point electrode 6 is connected to the flexible conductive polymer film layer 2 through conductive glue. Specifically, the flexible glue can be a polyester resin adhesive.

[0046] Furthermore, the measuring point electrode 6 can be set on the center line of the flexible polymer matrix film as needed to ensure that the measured resistance can truly reflect the deformation of the rib material. The Kelvin four-wire connection method is used to connect to the flexible conductive polymer film layer 2 to measure the resistance change of the flexible conductive polymer film layer 2. The wire spacing is 0.1~0.2mm. The Kelvin four-wire connection method can eliminate the impedance of wiring and contact resistance during the resistance measurement process, while ensuring that the current input line and the voltage reading line are independent. Figure 7 As shown, the influence of the change of the wire resistance during the stretching process on the output signal is avoided, thereby improving the measurement accuracy.

[0047] In this embodiment, a window is opened at the end of the stretchable flexible circuit film layer 1 and a conductive contact sheet 11 is provided. The conductive contact sheet 11 is connected to a multi-channel resistance acquisition device 22, and data acquisition is performed through the multi-channel resistance acquisition device 22.

[0048] like Figure 3 As shown, the protective shell 12 adopts a heat shrink tube, which is a double-layer structure with a flexible adhesive, the outer layer is made of polyolefin material, and the inner layer is made of flexible hot melt adhesive. The heat shrink tube has good durability as a protective shell, which can ensure that the smart sensing material is not disturbed by external moisture and acid-base media during the entire life cycle, and has good tensile properties. After it shrinks due to heat, it can be tightly bonded to the substrate of the smart sensing material, so that it can deform in coordination with the substrate.

[0049] like Figure 4 As shown, a plurality of the roadbed slope deformation sensing material units 9 are connected by an injection molding node 10, and the node is generated by a secondary injection molding process to obtain a roadbed slope deformation intelligent sensing geogrid 20. The roadbed slope deformation intelligent sensing geogrid 20 can be woven entirely with the roadbed slope deformation sensing material units 9, or can be woven with the roadbed slope deformation sensing material units 9 and ordinary strips 8 according to the needs in the actual application process.

[0050] The intelligent sensing geogrid 20 for roadbed slope deformation can not only play a role in reinforcing the roadbed slope, but also realize distributed deformation monitoring of the entire process of roadbed slope disaster in the roadbed project. The setting of the flexible conductive polymer film layer and the stretchable flexible circuit film layer can improve the sensing accuracy of roadbed slope deformation. When in use, the measuring electrode measures the resistance change of the flexible conductive polymer film layer due to deformation, and transmits the output signal to the multi-channel resistance acquisition device through the nano-silver particle wire and the conductive contact sheet, realizing the distributed monitoring of the deformation of the entire process of roadbed slope disaster.

[0051] Example 2

[0052] In a typical embodiment of the present invention, a method for preparing a distributed intelligent monitoring device for the entire process of roadbed slope disaster is proposed, such as Figure 5 As shown, the following steps are included:

[0053] (1) A high molecular polymer material is extruded into a plate, then directional stretched under heating conditions, and cut to obtain a geotechnical reinforcement tape layer. The width of the geotechnical reinforcement tape is 18-23 mm and the thickness is 1.5-2.5 mm. The high molecular polymer material can be high-density polyethylene, polyvinyl chloride, polypropylene resin, etc.

[0054] (2) A composite conductive filler is added to a polymer matrix solution, and an ultrasonic dispersion treatment is performed to form a conductive ink, and the conductive ink is coated on the geotechnical reinforcement tape layer to form a flexible conductive polymer film layer on the geotechnical reinforcement tape layer; wherein the coating method can be screen printing, spraying or spin coating.

[0055] Furthermore, when polyurethane is used as the polymer matrix:

[0056] When the composite conductive material adopts CB-CNT composite conductive filler, the dosage is 0.15-0.4wt%, and the mass ratios of zero-dimensional carbon black and one-dimensional carbon nanotubes to the total amount of filler are 40%-50% and 50%-60% respectively;

[0057] When the composite conductive material adopts CB-GN type composite conductive filler, the dosage is 0.1-0.3 wt%, and the mass ratios of zero-dimensional carbon black and two-dimensional graphene to the total amount of filler are 55%-70% and 30%-45% respectively;

[0058] When the composite conductive material adopts CB-CNT-GN composite conductive filler, the dosage is 0.5-1.5 wt%, and the mass ratios of zero-dimensional carbon black, one-dimensional carbon nanotubes, and two-dimensional graphene to the total amount of filler are 26%-33%, 33%-42%, and 25%-41%, respectively.

[0059] By limiting the concentration and mixing ratio of the above three composite conductive fillers, it is possible to ensure that the polyurethane matrix flexible conductive polymer film has the best sensing performance, so that the concentration of the conductive filler is as close as possible to the target filler dosage of the conductive polymer percolation effect.

[0060] Furthermore, when polydimethylsiloxane is used as the polymer matrix:

[0061] When the composite conductive material adopts CB-CNT composite conductive filler, the dosage is 0.1-0.3 wt%, and the mass ratios of zero-dimensional carbon black and one-dimensional carbon nanotubes to the total amount of filler are 40%-55% and 45%-60% respectively;

[0062] When the composite conductive material adopts CB-GN type composite conductive filler, the dosage is 0.08-0.2 wt%, and the mass ratios of zero-dimensional carbon black and two-dimensional graphene to the total amount of filler are 50%-60% and 40%-50% respectively;

[0063] When the composite conductive material adopts CB-CNT-GN composite conductive filler, the addition amount is 0.3-1.0wt%, and the mass ratios of zero-dimensional carbon black, one-dimensional carbon nanotubes, and two-dimensional graphene to the total amount of filler are 30%-36%, 33%-35%, and 29%-37%, respectively.

[0064] By limiting the concentration and mixing ratio of the above three composite conductive fillers, it is possible to ensure that the polydimethylsiloxane-based flexible conductive polymer film has the best sensing performance, so that the conductive filler concentration is as close as possible to the target filler dosage of the conductive polymer percolation effect.

[0065] The flexible conductive polymer film has a tensile sensitivity effect, that is, its resistivity increases with the increase of tensile strain. The resistivity-tensile strain constitutive model of the intelligent sensing grid can be obtained by conducting a tensile sensitivity test of the intelligent sensing geogrid. Figure 6 The intelligent sensing geogrid mechanical and electrical performance testing device in the invention tests the following two flexible conductive polymer films. The intelligent sensing geogrid 20 for roadbed slope deformation is fixed by a clamp 19 and connected to a high and low temperature universal testing machine 13 through a guide plate 21 and a wire. The high and low temperature universal testing machine 13 is used to test the mechanical properties of the intelligent sensing geogrid 20 for roadbed slope deformation. An environmental chamber 14 is provided in the high and low temperature universal testing machine 13. Under the action of a refrigeration device 15 and a heating device 16, the internal temperature range of the environmental chamber 14 can be adjusted within the range of -40°C to 150°C. The conductive properties of the intelligent sensing geogrid 20 for roadbed slope deformation are tested by a multimeter 17 and a computer 18.

[0066] When the composite conductive filler type of this embodiment is selected as CB-CNT-GN, the nanomaterial mixing ratio CB:CNT:GN is 1:1:1, the composite conductive filler dosage is 0.5wt%, and the polymer matrix is ​​polyurethane. The obtained intelligent sensing grid resistivity-tensile constitutive model is as follows:

[0067] ;

[0068] When the composite conductive filler type of this embodiment is selected as CB-CNT-GN, the nanomaterial mixing ratio CB:CNT:GN is 1:1:1, the composite conductive filler dosage is 0.5wt%, and the polymer matrix is ​​polydimethylsiloxane. The obtained intelligent sensing grid resistivity-tensile constitutive model is as follows:

[0069]

[0070] In the formula, It is an intelligent sensor that senses the resistance change of geogrid during stretching. R is the initial resistance of the intelligent sensing geogrid, It is the intelligent sensing of tensile strain produced by geogrid.

[0071] (3) The nanosilver particle composite conductive ink is used to print the measuring point electrodes and wires on the flexible polymer matrix film by inkjet printing technology, and then the flexible insulating ink is sprayed to wrap the measuring point electrodes and the wire layer to achieve insulation treatment of the measuring point electrodes and the conductive layer, thereby obtaining a stretchable flexible circuit film layer.

[0072] Wherein, the nano silver particle composite conductive ink is obtained by the following method:

[0073] The nanosilver particle / isopropanol dispersion is added to the carbon paste ink and mechanically stirred to obtain the nanosilver particle composite conductive ink, wherein the mixing ratio of the nanosilver particle / isopropanol dispersion to the carbon paste ink is 1:10, the solid content of the nanosilver particles is 0.02-0.06 wt%, and the inherent volume resistance of the carbon paste ink is 0.01Ω .

[0074] (4) pasting the stretchable flexible circuit film layer onto the flexible conductive polymer film layer, setting a window at the measuring point electrode, and connecting the measuring point electrode to the flexible conductive polymer film layer with a conductive adhesive; setting a window at the end of the flexible circuit film, and setting a conductive contact sheet, and connecting the conductive contact sheet to the multi-channel resistance acquisition device;

[0075] (5) The geotechnical reinforcement layer, the flexible conductive polymer film layer, and the stretchable flexible circuit film layer are encapsulated with a heat shrink tube to obtain a roadbed slope deformation sensing material unit;

[0076] (6) A plurality of the roadbed slope deformation sensing material units are connected by nodes and woven into a network by a secondary injection molding process to obtain a roadbed slope deformation intelligent sensing geogrid.

[0077] Among them, when using heat shrink tube for packaging, the heat shrink tube is heated to 84~120℃ to melt the inner layer of hot melt adhesive, tightly wrap the roadbed slope deformation sensing material unit, and complete the packaging.

[0078] In a specific implementation of this embodiment, the distributed intelligent monitoring device for the entire process of roadbed slope disaster is prepared in the following manner:

[0079] (1) A high-density polyethylene polymer is extruded into a plate, then directional stretched under heating conditions, and cut to obtain a geotechnical reinforcement tape layer. The width of the geotechnical reinforcement tape is 18 mm and the thickness is 1.5 mm.

[0080] (2) Preparation of composite conductive materials. When CB-CNT composite conductive fillers are used, the mixing ratio of the two is 1:1. 0.3wt% of the composite conductive filler is added to the polyurethane resin, and ultrasonic dispersion treatment is performed to form a conductive ink. The conductive ink is applied to the geotechnical reinforcement tape layer by spraying, and then placed in a vacuum oven at 100°C and heated for 1 hour to form a 50mm thick geotechnical reinforcement tape layer. Flexible conductive polymer film layer.

[0081] The resistivity-stretching constitutive model of the intelligent sensing grid obtained based on the above-mentioned flexible conductive polymer film layer is as follows:

[0082]

[0083] (3) Adding the nanosilver particle / isopropyl alcohol dispersion to the carbon paste ink, wherein the solid content of the nanosilver particles in the dispersion is 0.5wt%, and the inherent volume resistance of the carbon paste ink is 0.01Ω , the dispersion and the carbon paste ink were mixed in a ratio of 1:10, and then mechanically stirred for 60 min to obtain a nanosilver particle composite conductive ink;

[0084] Inkjet printing technology is used to print measuring point electrodes and wires with nanosilver particle composite conductive ink on a flexible polymer matrix film, and then flexible insulating ink is sprayed to wrap the measuring point electrodes and the wire layer to achieve insulation treatment of the measuring point electrodes and the conductive layer to obtain a stretchable flexible circuit film layer.

[0085] (4) pasting the stretchable flexible circuit film layer onto the flexible conductive polymer film layer, setting a window at the measuring point electrode, and connecting the measuring point electrode to the flexible conductive polymer film layer with a conductive adhesive; setting a window at the end of the flexible circuit film, and setting a conductive contact sheet, and connecting the conductive contact sheet to the multi-channel resistance acquisition device;

[0086] (5) The geotechnical reinforcement layer, the flexible conductive polymer film layer, and the stretchable flexible circuit film layer are encapsulated with a heat shrink tube to obtain a roadbed slope deformation sensing material unit;

[0087] (6) A plurality of the roadbed slope deformation sensing material units are connected by nodes and woven into a network by a secondary injection molding process to obtain a roadbed slope deformation intelligent sensing geogrid.

[0088] When the heat shrink tube is used for packaging, the heat shrink tube is heated to 84°C to melt the inner layer of hot melt adhesive, tightly wrapping the roadbed slope deformation sensing material unit to complete the packaging.

[0089] The above-mentioned intelligent sensing geogrid for roadbed slope deformation is horizontally laid inside the roadbed, such as Figure 8 As shown, the resistance change value between each measuring point of the intelligent sensing geogrid is obtained through a multi-channel resistance acquisition device, and the reinforcement strain is obtained based on the above-mentioned resistivity-tensile constitutive model. The infinite signal transmission function of the acquisition device is used to upload the collected data to the cloud server.

[0090] The maximum measured strain of the above-mentioned intelligent sensing geogrid for roadbed slope deformation is 20%, and the measurement accuracy is 0.1 , the sensitivity coefficient is 10.35.

[0091] Comparative Example

[0092] A pair of ratios is proposed to compare the sensing performance of the above specific implementation scheme, and the specific implementation scheme is as follows:

[0093] (1) Conductive carbon black was mixed with high-density polyethylene matrix particles at a target filler concentration of 47.5 wt% until uniform, and 5% silane coupling agent was added and mixed uniformly in a high-speed mixer.

[0094] (2) The uniform mixture is fed through an automatic suction machine, melted and mixed in a twin-screw extruder, slowly extruded under the traction of a traction machine, and finally cut into sensitive strips with a width of 18 mm and a thickness of 1.5 mm, and packaged in the same manner as the present invention.

[0095] (3) The smart strips are used as horizontal and vertical ribs, and nodes are molded at their intersections using an injection molding machine to form a grid.

[0096] (4) Using the same test device as the present invention, such as Figure 6 As shown, the resistivity-tensile constitutive model of the grid is obtained as follows:

[0097]

[0098] The maximum measured strain of the above grid is 10%, and the measurement accuracy is 1 , the sensitivity coefficient is 10.35.

[0099] Compared with the performance of the intelligent sensing geogrid for roadbed slope deformation obtained in the specific implementation of the present invention, the maximum measured strain of the grid in the comparative example is shortened by half, the measurement accuracy is reduced by ten times, the sensitivity coefficient is reduced by about 40%, and the measurement result is a typical parabolic relationship with low linearity.

[0100] Based on the above analysis, the intelligent sensing geogrid for roadbed slope deformation of the present invention has the following beneficial effects:

[0101] (1) The use of multi-dimensional nano-conductive fillers can reduce the target filler concentration. On the one hand, it can achieve higher sensing performance at a lower filler dosage. On the other hand, it can also prevent problems such as reduced toughness of smart geosynthetics due to excessive addition of carbon nanoparticles.

[0102] (2) Compared with the melt blending method, the solution blending method for preparing the flexible conductive polymer film layer can make the internal conductive filler dispersed more evenly, which is beneficial to improving the sensing performance of the deformation sensing material unit.

[0103] (3) The deformation sensing material unit in the present invention has high linearity, large strain range, high sensitivity and high measurement accuracy.

[0104] Example 3

[0105] In a typical embodiment of the present invention, a distributed monitoring method for the entire process of roadbed slope disaster is proposed, such as Figure 8 As shown, the following steps are included:

[0106] The intelligent sensing geogrid 20 for sensing roadbed slope deformation is buried inside the slope of the roadbed 23, and the wires led out of the intelligent sensing geogrid 20 for sensing roadbed slope deformation are connected to the multi-channel resistance acquisition device 22. The resistance of the flexible conductive polymer film layer is collected by the multi-channel resistance acquisition device 22 and the roadbed slope deformation data is output.

[0107] The resistance signal of the intelligent sensing geogrid is obtained by adopting a multi-channel resistance acquisition system, and the distributed deformation information of the roadbed slope during the whole process of the roadbed slope disaster is calculated based on the strain-resistance constitutive model of the intelligent sensing geogrid; in order to eliminate the influence of the resistance change of the circuit wire during the stretching process, the multi-channel resistance signal acquisition system adopts a measurement technology that can eliminate the influence of circuit resistance (for example, the bridge method, the four-lead method, etc.); the strain-resistance constitutive model of the intelligent sensing geogrid is obtained by conducting a grid tension test, and the specific steps are as follows: first, according to the "Testing Procedures for Geosynthetics", the intelligent sensing geogrid is cut into specimens of the required size for the test, and the grid specimen is stretched using a universal testing machine, and the resistance change of the grid during the stretching process is tested by a multimeter, and then the strain-resistance relationship model of the intelligent sensing geogrid is established based on data fitting algorithms such as strong linear fitting model, polynomial fitting model, multivariate linear model and multivariate polynomial fitting model.

[0108] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A distributed intelligent monitoring device for the entire process of roadbed slope disaster, characterized in that: It includes a roadbed slope deformation sensing material unit, which includes a geotechnical reinforcement belt layer, a flexible conductive polymer film layer and a stretchable flexible circuit film layer arranged in sequence in a protective shell; A plurality of the roadbed slope deformation sensing material units are woven in warp and weft directions to form a roadbed slope deformation intelligent sensing geogrid; Measuring point electrodes are arranged at a plurality of set positions of the stretchable flexible circuit film layer, each measuring point electrode is led to the end of the stretchable flexible circuit film layer through a wire, the measuring point electrode measures the resistance of the flexible conductive polymer film layer and outputs a signal through the wire; The flexible conductive polymer film layer comprises a polymer matrix, a composite conductive material is added into the polymer matrix, the composite conductive material is made of nanomaterials of different dimensions, and the composite conductive material and the polymer matrix are uniformly mixed by ultrasonic dispersion treatment; The polymer matrix is ​​polyurethane or polydimethylsiloxane; The nanomaterials of different dimensions include at least one of one-dimensional carbon nanotubes and two-dimensional graphene, and zero-dimensional carbon black; The stretchable flexible circuit film layer comprises a flexible polymer matrix film, on which nanosilver particle composite conductive ink is printed to form measuring point electrodes and wires, and on which flexible insulating ink is sprayed to achieve insulation; The stretchable flexible circuit film layer is pasted to the flexible conductive polymer film layer, a window is provided at the measuring point electrode, and the measuring point electrode is bonded to the flexible conductive polymer film layer by conductive glue; The measuring point electrodes are arranged on the center line of the flexible polymer matrix film, and each measuring point electrode is connected to two wires to detect the resistance change of the flexible conductive polymer film layer in real time; The ends of the stretchable flexible circuit film layer are opened with windows and provided with conductive contacts, and the conductive contacts are connected to a multi-channel resistance collection device.

2. The distributed intelligent monitoring device for the entire process of roadbed slope disaster according to claim 1 is characterized in that: The measuring point electrodes are attached to the surface of the flexible conductive polymer film layer, and the tensile strain distributed on the flexible conductive polymer film layer is obtained according to the initial resistance and resistance change rate obtained by each measuring point electrode.

3. The distributed intelligent monitoring device for the entire process of roadbed slope disaster according to claim 1 is characterized in that: The thickness of the flexible polymer matrix film is 0.02-0.05 mm, so that the flexible polymer matrix film can be deformed in coordination with the bottom substrate during the deformation process.

4. The distributed intelligent monitoring device for the entire process of roadbed slope disaster according to claim 1, characterized in that: The geotechnical reinforcement belt layer is made of high molecular polymer material, and the thickness of the geotechnical reinforcement belt layer is 1.5-2.5 mm.

5. The distributed intelligent monitoring device for the entire process of roadbed slope disaster according to claim 4, characterized in that: The high molecular polymer material includes high density polyethylene, polyvinyl chloride and polypropylene resin.

6. The distributed intelligent monitoring device for the entire process of roadbed slope disaster according to claim 1, characterized in that: The protective shell adopts a heat shrink tube, and the heat shrink tube is a double-layer structure with a flexible adhesive, wherein the outer layer is made of a polyolefin material, and the inner layer is made of a flexible hot melt adhesive.

7. A method for preparing a distributed intelligent monitoring device for the entire process of roadbed slope disaster according to any one of claims 1 to 6, characterized in that: The following steps are involved: preparing a geotechnical reinforcement tape layer; A composite conductive material made of nanomaterials of different dimensions is added to a polymer matrix solution, and an ultrasonic dispersion treatment is performed to form a conductive ink, and the conductive ink is applied to a geotechnical reinforcement tape layer to form a flexible conductive polymer film layer; Measuring point electrodes and conducting wires are arranged on a flexible polymer matrix film to obtain a stretchable flexible circuit film layer; the measuring point electrodes and conducting wires are printed on the flexible polymer matrix film using nano-silver particle composite conductive ink, and after printing the measuring point electrodes and conducting wires, flexible insulating ink is sprayed to obtain a stretchable flexible circuit film layer; the nano-silver particle composite conductive ink is obtained by the following method: The dispersion formed by mixing nanosilver particles and isopropyl alcohol is added to the carbon paste ink, and the nanosilver particle composite conductive ink is obtained after mechanical stirring, wherein the solid content of the nanosilver particles is 0.02-0.06 wt %; Pasting the stretchable flexible circuit film layer on the flexible conductive polymer film layer, and connecting the measuring point electrodes to the flexible conductive polymer film layer; The geotechnical reinforcement belt layer, the flexible conductive polymer film layer and the stretchable flexible circuit film layer are encapsulated to obtain a roadbed slope deformation sensing material unit; A plurality of the roadbed slope deformation sensing material units are woven into a network in the warp and weft directions to obtain a roadbed slope deformation intelligent sensing geogrid.

8. The method for preparing the distributed intelligent monitoring device for the whole process of roadbed slope disaster according to claim 7, characterized in that: When polyurethane is used as the polymer matrix: When the composite conductive material adopts zero-dimensional carbon black-one-dimensional carbon nanotube composite conductive filler, the dosage is 0.15-0.4wt%, and the mass ratios of zero-dimensional carbon black and one-dimensional carbon nanotube to the total amount of filler are 40%-50% and 50%-60% respectively; When the composite conductive material adopts zero-dimensional carbon black-two-dimensional graphene composite conductive filler, the dosage is 0.1-0.3wt%, and the mass ratios of zero-dimensional carbon black and two-dimensional graphene to the total amount of filler are 55%-70% and 30%-45% respectively; When the composite conductive material adopts zero-dimensional carbon black-one-dimensional carbon nanotube-two-dimensional graphene composite conductive filler, the dosage is 0.5-1.5 wt%, and the mass ratios of zero-dimensional carbon black, one-dimensional carbon nanotube and two-dimensional graphene to the total amount of filler are 26%-33%, 33%-42% and 25%-41% respectively.

9. The method for preparing the distributed intelligent monitoring device for the whole process of roadbed slope disaster according to claim 7, characterized in that: When polydimethylsiloxane is used as the polymer matrix: When the composite conductive material adopts zero-dimensional carbon black-one-dimensional carbon nanotube composite conductive filler, the dosage is 0.1-0.3wt%, and the mass ratios of zero-dimensional carbon black and one-dimensional carbon nanotube to the total amount of filler are 40%-55% and 45%-60% respectively; When the composite conductive material adopts a zero-dimensional carbon black-two-dimensional graphene composite conductive filler, the dosage is 0.08-0.2wt%, and the mass ratios of zero-dimensional carbon black and two-dimensional graphene to the total amount of filler are 50%-60% and 40%-50% respectively; When the composite conductive material adopts zero-dimensional carbon black-one-dimensional carbon nanotube-two-dimensional graphene composite conductive filler, the dosage is 0.3-1.0wt%, and the mass ratios of zero-dimensional carbon black, one-dimensional carbon nanotube and two-dimensional graphene to the total amount of filler are 30%-36%, 33%-35% and 29%-37% respectively.

10. The method for preparing the distributed intelligent monitoring device for the whole process of roadbed slope disaster according to claim 7, characterized in that: When using heat shrink tube for packaging, heat the heat shrink tube to 84~120℃ to melt the inner layer of hot melt adhesive, tightly wrap the roadbed slope deformation sensing material unit, and complete the packaging.

11. A distributed monitoring method for the entire process of roadbed slope disaster, implemented by using the monitoring device according to any one of claims 1 to 6, characterized in that: The following steps are involved: The intelligent sensing geogrid for roadbed slope deformation is buried inside the roadbed slope, and the wires led out from the intelligent sensing geogrid for roadbed slope deformation are connected to a multi-channel resistance acquisition device. The resistance of the flexible conductive polymer film layer is collected through the multi-channel resistance acquisition device and the roadbed slope deformation data is output.

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