A distributed flexible intelligent monitoring device, method and system for soil and rock mass disasters

Abstract

This invention belongs to the field of geotechnical engineering safety monitoring technology, and discloses a distributed flexible intelligent monitoring device, method, and system for geological disasters in soil and rock. It includes a monitoring unit and a coupling unit outside the monitoring unit. The monitoring unit comprises, from bottom to top, a base layer, a flexible conductive layer, a brittle conductive layer, and a circuit layer. The flexible conductive layer includes a first flexible substrate, a one-dimensional conductive material, and a two-dimensional conductive filler. The brittle conductive layer uses a conductive material with high intrinsic stiffness. The circuit layer includes a second flexible substrate on which multiple measuring electrodes are arranged. Some measuring electrodes are connected to the flexible conductive layer, and some are connected to the brittle conductive layer. The brittle conductive layer and the flexible conductive layer are connected in parallel. This invention employs a rigid-flexible coupled double-layer conductive structure. The brittle conductive layer can capture the initiation of micro-cracks in soil and rock, thus improving the sensitivity of the monitoring unit. The coupling unit enhances the coupling between the monitoring device and the soil and rock, thereby improving monitoring accuracy.

Description

Technical Field

[0001] This invention belongs to the field of geotechnical engineering safety monitoring technology, specifically relating to a distributed flexible intelligent monitoring device, method, and system for geotechnical disasters. Background Technology

[0002] In recent years, the proportion of road projects traversing complex geological environments (such as mountainous areas, fault zones, and soft soil regions) has been increasing year by year. The resulting high-risk rock and soil masses have become a major hidden danger threatening traffic safety, necessitating the monitoring of rock and soil deformation. Traditional techniques mainly rely on discretely deploying sensors at single points in the test area. However, rock and soil masses are heterogeneous and discontinuous geological materials, and their deformation and failure exhibit localized characteristics. Especially after the formation of shear zones, deformation is mainly concentrated in narrow banded areas, resulting in a limited monitoring range for single-point sensor deployments, making it difficult to capture the entire process of shear zone initiation and expansion.

[0003] To address the aforementioned technical problems, existing technology discloses a distributed intelligent monitoring device for the entire process of roadbed slope disasters. This device includes a deformation sensing unit, which comprises a geosynthetic reinforcement layer, a flexible conductive film layer, and a flexible circuit film layer sequentially arranged within a protective shell. Measuring electrodes are positioned at designated locations on the flexible circuit film layer. Multiple deformation sensing units are woven into a mesh to form a sensing geogrid. The resistance change of the flexible conductive film layer is measured using the measuring electrodes to perform distributed monitoring of roadbed slope disasters.

[0004] Although the above scheme provides more comprehensive distributed monitoring of roadbed slopes, it still has the following shortcomings: The deformation sensing unit of the above scheme is a flexible sensor. When the roadbed slope undergoes deformation and displacement, it can continuously monitor the deformation of the roadbed slope. However, the deformation sensing unit cannot effectively detect the small deformation and displacement (e.g., less than 2 mm) that occurs in the early stage of failure of the soil and rock mass. It is difficult to accurately monitor the complete evolution process of the soil and rock mass from the initiation of micro-cracks to the overall macroscopic sliding along the shear zone. In addition, the above scheme embeds the sensing geogrid inside the roadbed slope. When the roadbed slope is deformed, the coupling degree between the roadbed soil and rock mass and the sensing geogrid is poor, which leads to the deviation between the monitoring results and the actual shear displacement, affecting the monitoring accuracy. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a distributed flexible intelligent monitoring device, method, and system for soil and rock disasters, which can solve the technical problems of existing technologies being unable to monitor the complete evolution process of soil and rock failure and having poor monitoring accuracy.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: Firstly, a distributed flexible intelligent monitoring device for geological disasters in soil and rock masses is provided, including a monitoring unit and a coupling unit; The monitoring unit includes a flexible conductive layer, a brittle conductive layer, and a circuit layer arranged sequentially from bottom to top within the encapsulation layer; The flexible conductive layer includes a first flexible substrate, a one-dimensional conductive material, and a two-dimensional conductive filler. The one-dimensional conductive material is overlapped into a network within the first flexible substrate, and the two-dimensional conductive filler is filled in the gaps between the one-dimensional conductive material. The brittle conductive layer is made of a conductive material with an intrinsic stiffness greater than a set value; The circuit layer includes a second flexible substrate, on which multiple measuring electrodes are arranged. Some measuring electrodes are connected to a flexible conductive layer, and some measuring electrodes are connected to a brittle conductive layer. The brittle conductive layer and the flexible conductive layer are connected in parallel. The coupling unit is wrapped around the outside of the monitoring unit and together they are filled into the soil and rock mass.

[0007] Furthermore, the rock and soil mass includes frictional rock and soil mass, cohesive rock and soil mass, and brittle rock and soil mass; For frictional soil and rock masses, the coupling unit uses a material with good permeability and bonding properties; For cohesive soil and rock masses, the coupling unit uses a material with elasticity and bonding properties; For brittle rock and soil masses, the coupling unit uses grouting materials with strong permeability and consolidation capacity.

[0008] Furthermore, the substrate, the first flexible substrate, the second flexible substrate, and the encapsulation layer are made of any one of polydimethylsiloxane, Ecoflex, and polyurethane.

[0009] Furthermore, the one-dimensional conductive material uses multi-walled carbon nanotubes, and the two-dimensional conductive material uses graphene nanosheets, with a mass ratio of 1:3 to 3:1.

[0010] Furthermore, the thickness of the second flexible substrate is less than that of the first flexible substrate, and they are made of the same material.

[0011] Secondly, a disaster monitoring method for soil and rock masses is provided, which utilizes the aforementioned distributed flexible intelligent monitoring device for soil and rock mass disasters. The specific steps include: Determine the monitoring area and bury monitoring units in layers along the depth direction of the monitoring area; Before installation, select a coupling unit according to the type of soil and rock mass, and connect the monitoring unit to the acquisition equipment; The coupling unit is coated on the surface of the monitoring unit, and trenches or holes are excavated in layers in the monitoring area. The coupling unit is injected into the trenches or holes, and then the monitoring unit is placed in the trenches or holes. The acquisition device is equipped with a preset resistance-strain-shear displacement model and multiple warning thresholds. The acquisition device collects the monitoring signals from the monitoring unit and substitutes them into the model to output shear displacement values. The output shear displacement values ​​are compared with the preset multiple warning thresholds to output different warning signals.

[0012] Furthermore, the monitoring units are laid out in layers at set intervals along the depth direction, and the monitoring frequency of the acquisition equipment is as follows: the acquisition interval is long under normal conditions, and the acquisition interval is shortened when there is rainfall or changes in groundwater level; when the monitoring data shows abnormal fluctuations, continuous and uninterrupted acquisition is performed.

[0013] Furthermore, the resistance-strain-shear displacement model includes the resistance-strain conversion model and the strain-shear displacement model; The resistance-strain conversion model is ; In the formula: To monitor the resistance change of the unit during the stretching process; The initial resistance of the monitoring unit; For monitoring the tensile strain generated by the unit; The sensitivity coefficient is denoted by , and the ambient temperature is denoted by . (°C) and loading strain rate (s) -1 bivariate function ;in, This is the temperature influence coefficient. The influence coefficient of the loading strain rate, These are fitting constants, all obtained through calibration experiments.

[0014] Furthermore, the strain-shear displacement model is as follows: ; In the formula: This represents the soil shear displacement. For monitoring segment length, Let be the strain distribution function along the length of the monitoring unit; The coefficient for interface coupling efficiency is given by the equation, where brittle rock and soil mass is represented by the coefficient. =1, cohesive soil and rock mass =0.7, frictional soil and rock mass The values ​​are related to the type of soil and rock mass, water content, and overlying stress, and are determined through calibration tests.

[0015] Thirdly, a disaster monitoring system for soil and rock masses is provided, which operates the above-mentioned monitoring method and includes a data acquisition module, an analysis module, and an early warning module connected in sequence. The data acquisition module includes multiple monitoring devices, which are arranged in layers along the depth direction of the test area; The analysis module has a built-in resistance-strain-shear displacement model, which is used to receive and analyze the monitoring information from the acquisition module and output the shear displacement value. The early warning module has built-in multi-level early warning thresholds, which are used to receive the shear displacement value output by the analysis module and output early warning signals.

[0016] Compared with the prior art, the advantages and positive effects of this invention are: The monitoring device of this invention includes a monitoring unit and a coupling unit. The monitoring unit comprises a brittle conductive layer and a flexible conductive layer connected in parallel, forming a "rigid-flexible coupling" double-layer conductive structure. Due to its high stiffness and poor ductility, the brittle conductive layer captures the initiation and propagation of micro-cracks in the early stages of soil and rock failure, thus solving the problem of low sensitivity in existing flexible sensors. This improves the sensitivity of the monitoring unit and enhances the monitoring of the complete evolution process of soil and rock failure. The coupling unit is wrapped around the monitoring unit and filled into the soil and rock mass, increasing the coupling between the monitoring device and the soil and rock mass, and strengthening the synchronous deformation of the monitoring unit and the soil and rock mass. This solves the problem of discrepancies between monitoring results and actual shear displacement in existing technologies, thus improving monitoring accuracy. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0018] Figure 1 This is a schematic diagram of the monitoring unit of Embodiment 1, Embodiment 2, or Embodiment 3 of the present invention; Figure 2 This is a schematic diagram illustrating the preparation process of the monitoring unit in Embodiment 1, Embodiment 2, or Embodiment 3 of the present invention; Figure 3 This is a flowchart of the monitoring method according to Embodiment 2 of the present invention; Figure 4 This is a schematic diagram of the layered arrangement of the monitoring unit in Embodiment 2 of the present invention; Figure 5 This is a schematic diagram of the monitoring unit in Embodiment 2 of the present invention during a calibration test; In the picture: 1. Monitoring unit; 2. Substrate layer; 3. Flexible conductive layer; 4. Brittle conductive layer; 5. Circuit layer; 51. Measuring electrode; 52. Wire; 6. High and low temperature universal testing machine; 7. Multi-channel multimeter; 8. Computer. Detailed Implementation

[0019] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0020] The present invention will now be described in detail with reference to the accompanying drawings.

[0021] Example 1 This embodiment discloses a distributed flexible intelligent monitoring device for soil and rock disasters, including a monitoring unit 1 and a coupling unit. The monitoring unit 1 is used to sense the deformation of the soil and rock mass and convert the physical deformation of the soil and rock mass into an electrical signal. The coupling unit is used to tightly connect the monitoring unit 1 to the soil and rock mass to ensure the effective transmission of deformation.

[0022] like Figure 1 As shown, the monitoring unit 1 includes, from bottom to top, a base layer 2, a flexible conductive layer 3, a brittle conductive layer 4, and a circuit layer 5, all encapsulated within an encapsulation layer. It should be noted that the encapsulation layer provides external protection for the monitoring unit 1, shielding it from external environmental factors (such as moisture and mechanical damage). The base layer 2 provides support for the flexible conductive layer 3, the brittle conductive layer 4, and the circuit layer 5. The flexible conductive layer 3 and the brittle conductive layer 4 are responsible for sensing the deformation of the soil and rock mass, while the circuit layer 5 is responsible for monitoring the resistance changes of the flexible conductive layer 3 and the brittle conductive layer 4, and simultaneously transmitting the resistance change signals to external acquisition equipment.

[0023] In this embodiment, a flexible conductive layer 3 is coated on a substrate layer 2. The flexible conductive layer 3 includes a first flexible substrate, a one-dimensional conductive material, and a two-dimensional conductive filler. The one-dimensional conductive material is overlapped into a network within the first flexible substrate, and the two-dimensional conductive filler fills the gaps in the one-dimensional conductive material. It is understood that the first flexible substrate provides an adhesion surface for the conductive material. The one-dimensional conductive material is fibrous or tubular, and forms a conductive network through overlap. The two-dimensional conductive filler is sheet-like and fills the gaps in the one-dimensional conductive material, together forming a conductive layer with good conductivity and sensitivity to tensile deformation, enabling continuous monitoring of soil and rock deformation.

[0024] It should also be noted that this design of one-dimensional conductive material and two-dimensional conductive filler enables the construction of a dense and stable multi-dimensional conductive network at a low filler doping concentration (e.g., total integral of 0.5%–5%), giving the flexible conductive layer 3 excellent initial conductivity (volume resistivity as low as below 10 Ω·cm) and preventing signal instability due to tensile fracture. The flexible conductive layer 3 is mainly used to monitor the medium to large deformation stages of rock and soil (such as shear band expansion and macroscopic slip stages).

[0025] In this embodiment, the brittle conductive layer 4 is made of a conductive material with an intrinsic stiffness (Young's modulus of the material within the elastic deformation range) greater than a set value (in this embodiment, a Young's modulus greater than 70 GPa), such as gold, silver, or copper. The brittle conductive layer 4 is laid on the surface of the flexible conductive layer 3. The brittle conductive layer 4 is highly sensitive to minute deformations or cracks. When microcracks initiate in the rock and soil mass, the brittle conductive layer 4 deforms first, thereby allowing monitoring of a sharp increase in the resistance of the brittle conductive layer 4. It should be noted that as the deformation of the rock and soil mass continues to increase, the brittle conductive layer 4 fails, and the flexible conductive layer 3 takes over the main monitoring role.

[0026] In this embodiment, circuit layer 5 includes a second flexible substrate, such as... Figure 1 As shown, multiple measuring electrodes 51 are arranged on the second flexible substrate. Some measuring electrodes 51 are connected to the flexible conductive layer 3, and some measuring electrodes 51 are connected to the brittle conductive layer 4. The encapsulation layer has interfaces at the measuring electrodes 51 for connecting external acquisition equipment to monitor the resistance changes of each conductive layer. It can be understood that the second flexible substrate has the same tensile properties as the first flexible substrate to adapt to the overall deformation of the monitoring unit 1.

[0027] Understandably, the brittle conductive layer 4 and the flexible conductive layer 3 are connected in parallel to form a "rigid-flexible coupling" double-layer conductive structure. When the soil and rock mass is in the pre-failure stage, it undergoes minute deformation (micro-strain level). Due to its high stiffness and poor ductility, the brittle conductive layer 4 will preferentially develop micron-level cracks, causing a drastic change in its conductive path and a significant increase in resistance. This enables the monitoring unit 1 to acquire initial sensitivity (for example, a sensitivity coefficient of over 50 within the 0-2% strain range), capturing the initiation and propagation of micro-cracks in the pre-failure stage of the soil and rock mass. This can solve the problem of low sensitivity in existing flexible sensors.

[0028] Understandably, as the strain further increases (2%–8%), the brittle conductive layer 4 cracks saturate, and the flexible conductive layer 3 dominates the sensing response, continuing to output a stable signal (the sensitivity coefficient remains between 5 and 15). It should be noted that when the strain exceeds 8%, the lower conductive network undergoes slippage and rearrangement, and the rate of change of resistance rises steadily again until the monitoring unit 1 breaks (the elongation at break can reach over 100%).

[0029] It should be noted that although monitoring unit 1 can monitor the entire process of soil and rock mass from microcrack initiation to macroscopic sliding, soil and rock mass is a heterogeneous and discontinuous geological material. Directly burying monitoring unit 1 within the soil and rock mass may lead to interface slippage, causing the monitoring data to deviate from the actual shear displacement. To address this, this embodiment encases a coupling unit around monitoring unit 1, filling it within the soil and rock mass together. This enhances the coupling between the monitoring device and the soil and rock mass, enabling monitoring unit 1 to deform synchronously with the surrounding soil and rock mass, thereby improving the representativeness and accuracy of the monitoring data.

[0030] It is understandable that there are many types of soil and rock masses, such as frictional soil and gravelly soil, cohesive soil and expansive soil, as well as brittle soil and rock masses such as fractured rock and hard rock. Different types of soil and rock masses require different coupling units (i.e. interface filling materials).

[0031] In this embodiment, for frictional soil and rock masses, the coupling unit uses a material with good permeability and adhesion as the interface filling material, such as epoxy resin; for cohesive soil and rock masses, the coupling unit uses a material with elasticity and adhesion as the interface filling material, such as polyurethane; for brittle soil and rock masses, the coupling unit uses a grouting material with strong permeability and consolidation ability as the interface filling material, such as ordinary cement grout containing nano-silica sol.

[0032] It should be noted that frictional soil and rock masses have relatively high porosity, and stress is transferred between particles through friction. Epoxy resin has good permeability and, after curing, possesses high strength and adhesion. Epoxy resin can penetrate into the pores of the frictional material, forming a unified structure after curing, thus enhancing the interfacial stiffness and stress transfer efficiency between monitoring unit 1 and the soil and rock mass. Besides epoxy resin, materials with good permeability and adhesion, such as polyester resin or acrylic resin, can also be used.

[0033] In cohesive soil and rock masses, stress is transferred between particles through cohesion. These masses exhibit significant volume changes with varying moisture content and possess a certain degree of viscosity. Polyurethane materials possess excellent elasticity and flexibility, enabling them to adapt to the deformation of cohesive soil and rock masses. Furthermore, polyurethane materials exhibit good adhesion, ensuring close contact between monitoring unit 1 and the soil and rock mass and reducing interfacial slippage. Besides polyurethane, other polymeric materials with good elasticity and adhesion, such as silicone rubber or butyl rubber, can also be used.

[0034] Brittle rock and soil masses typically do not undergo significant plastic deformation under stress, but they can suddenly fracture when the stress reaches a certain limit. Examples include fractured rock masses and hard rocks. These types of rock and soil masses may contain internal fissures or joints, and their surfaces are rough and uneven. Ordinary cement grout containing nano-silica sol has extremely low viscosity, allowing it to penetrate deeply into micro-fissures. After solidification, it forms a filler with higher strength and stiffness, filling the gaps between the rock and soil mass and monitoring unit 1, achieving integrated coupling between monitoring unit 1 and the rock and soil mass, and improving the continuity of stress transmission. In addition to ordinary cement grout containing nano-silica sol, ultrafine cement grout or chemical grout, which have good permeability and consolidation capabilities, can also be used as grouting materials.

[0035] In this embodiment, the base layer 2, the first flexible matrix, the second flexible matrix, and the encapsulation layer are any one of polydimethylsiloxane (hereinafter referred to as "PDMS"), Ecoflex, and polyurethane. PDMS's low elastic modulus and high elongation at break allow it to withstand significant deformation without failure; Ecoflex is a polymer material from BASF, possessing flexibility and elasticity; and polyurethane exhibits abrasion resistance, tear resistance, oil resistance, and good elastic recovery. It is understood that the base layer 2, the first flexible matrix, the second flexible matrix, and the encapsulation layer all need to possess tensile properties to ensure that they can deform accordingly during the deformation of the soil and rock mass without damage.

[0036] In this embodiment, the monitoring device has a strip-shaped structure. This strip-shaped structure can bend or stretch synchronously with the deformation of the soil and rock mass, reducing relative slippage between the monitoring device and the soil and rock mass and improving monitoring accuracy. Inside the monitoring unit 1, the measuring electrode 51 is connected to the surface of the circuit layer 5 via conductive adhesive. The measuring electrode 51 is connected to the flexible conductive layer 3 or the brittle conductive layer 4 via wires 52. In this embodiment, inkjet printing technology is used to print the measuring electrode 51 and wires 52 onto the second flexible substrate using nano-silver particle composite conductive ink. Then, flexible insulating ink is sprayed to insulate the measuring electrode and the conductive layer. Specifically, nano-silver particle / isopropanol dispersion is added to carbon paste ink and mechanically stirred to obtain the nano-silver particle composite conductive ink.

[0037] In this embodiment, the one-dimensional conductive material is multi-walled carbon nanotubes (hereinafter referred to as "CNTs"), and the two-dimensional conductive material is graphene nanosheets (hereinafter referred to as "GNs"), with a mass ratio of 1:3 to 3:1.

[0038] The preparation process of monitoring unit 1 is as follows: PDMS and curing agent are mixed at a mass ratio of 10:1, vacuum degassing is performed for 15 minutes, and the mixture is injected into a strip mold. It is then pre-cured at 80°C for 120 minutes to form a base layer 2 with a thickness of 0.5 to 1.0 cm. Vacuum degassing is performed to remove air bubbles generated during the mixing process, avoid voids in the base layer 2, and ensure the uniformity and mechanical properties of the base layer 2. like Figure 2 As shown, CNTs and GNs were mixed at a mass ratio of 1:1, added to chloroform solvent, and ultrasonically dispersed for 30 minutes; then PDMS prepolymer was added, and ultrasonic dispersion was continued for 1 hour; finally, a dispersant was added, and the mixture was magnetically stirred for 30 minutes to obtain a conductive slurry. The total mass fraction of CNTs and GNs was 3%.

[0039] The conductive paste is uniformly coated onto the surface of the substrate 2 by screen printing or scraping, with a thickness controlled between 50 and 100 μm. Then it is cured at 80°C for 2 hours to form a flexible conductive layer 3. A metal thin film was deposited on the surface of the flexible conductive layer 3 using magnetron sputtering. The sputtering parameters were: a base vacuum of 5 × 10⁻⁶. -4 With a working pressure of 0.5 Pa, a sputtering power of 100 W, and a time of 30 seconds, a brittle conductive layer with a thickness of 50 nm is obtained; the target material for magnetron sputtering can be gold, silver, copper, nickel, or their alloys, or other metals with good conductivity. Along the length of the monitoring unit 1, a pair of measuring electrodes 41 are set at a set distance (e.g., 0.5m), and nano-silver wires 52 are printed to connect the brittle conductive layer 4 and the flexible conductive layer 3 respectively, and then baked at 80°C for 30 minutes to cure; then interfaces are laid at the measuring electrodes, and then Ecoflex encapsulation layer is coated on the surface of the monitoring unit 1.

[0040] In this embodiment, the thickness of the second flexible substrate is less than that of the first flexible substrate, which helps to maintain the overall flexibility of the monitoring unit 1. The material of the second flexible substrate can be the same as that of the first flexible substrate, such as polydimethylsiloxane, and a thin layer can be formed by scraping or spraying.

[0041] Example 2 This embodiment discloses a disaster monitoring method for soil and rock masses, utilizing a distributed flexible intelligent monitoring device for soil and rock mass disasters disclosed in Embodiment 1, such as... Figure 3 As shown, the specific steps include: The potential sliding surface monitoring area of ​​the rock and soil mass is determined, and multiple monitoring units are buried in layers from the top of the slope to the bottom of the slope along the depth direction of the monitoring area; this layered laying method can effectively construct the deformation profile inside the rock and soil mass. Before installation, select the appropriate interface filling material according to the type of rock and soil, and connect the monitoring unit 1 to the acquisition device. The acquisition device acquires the monitoring signal of the monitoring device. The monitoring signal is the resistance signal of the electrode 51 at each measuring point. During installation, the interface filling material is evenly coated on the surface of the monitoring unit 1, and trenches or holes are excavated in layers in the sliding surface monitoring area. The interface filling material is injected into the trenches or holes, and then the monitoring unit 1 is placed in the trenches or holes. After the interface material is cured, it forms a transition layer with controllable thickness, achieving close adhesion between monitoring unit 1 and the soil and rock mass; The acquisition device has a preset resistance-strain-shear displacement model. The acquisition device substitutes the acquired monitoring signal into the resistance-strain-shear displacement model and outputs the shear displacement value. The data acquisition device also sets multiple warning thresholds. The output shear displacement value is compared with the set multiple warning thresholds to output different warning signals.

[0042] Determining the monitoring area for potential sliding surfaces in soil and rock masses involves identifying the areas within the mass most likely to experience sliding failure through geological surveys, historical data analysis, or numerical simulations. Within these areas, multiple monitoring devices are vertically deployed at predetermined depth intervals to capture the approximate direction of the sliding surface. In this embodiment, for homogeneous soil and rock slopes, a variational method is used to determine the critical sliding surface: using the safety factor as the objective function, the location of the critical sliding surface is directly solved by combining dimensionality reduction and extremum finding with iterative calculations, without requiring any artificial assumptions about the shape of the sliding arc. For complex heterogeneous rock slopes, the finite element strength reduction method or the discrete element method (such as UDEC, 3DEC) can be used.

[0043] In this embodiment, within the defined potential sliding surface region, such as Figure 4 As shown, monitoring units 1 are laid in layers along the depth direction at a set interval (e.g., 0.5m to 2.0m); each layer of monitoring units 1 is laid along the main measuring line perpendicular to the sliding direction, and the connector of the monitoring unit 1 is connected to the acquisition equipment (e.g., a multi-channel data acquisition system) through an electric wire; the monitoring frequency of the multi-channel data acquisition system is set as follows: data is collected once per hour under normal conditions; when there is rainfall or changes in groundwater level, the frequency is increased to once every 20 minutes; when abnormal fluctuations occur in the monitoring data, the system switches to continuous acquisition mode.

[0044] It should be noted that monitoring unit 1 is laid out along the main survey line perpendicular to the sliding direction to ensure that monitoring unit 1 can detect the shear deformation generated during the sliding of the soil and rock mass to the greatest extent.

[0045] The dynamic adjustment of monitoring frequency not only ensures the timely acquisition of high-density data during critical periods, providing sufficient basis for early warning and emergency response, but also effectively saves system energy consumption and data storage space during periods of stable soil and rock mass, avoiding the collection of invalid data, thereby improving the operating efficiency of the multi-channel data acquisition system.

[0046] It should be noted that, unlike existing technologies that collect the resistance of the flexible conductive film layer and directly output roadbed slope deformation data, this embodiment considers the interfacial slippage between monitoring unit 1 and the soil mass. This means that there is an error in the correlation between the resistance signal and strain / shear displacement. Therefore, this embodiment introduces a coupling efficiency coefficient η to calculate the actual shear displacement. This design converts the resistance signal into shear displacement of the soil mass deformation, providing a direct basis for disaster early warning.

[0047] In this embodiment, the resistance-strain-shear displacement model includes a resistance-strain conversion model and a strain-shear displacement model.

[0048] Specifically, based on the fact that the internal conductive network structure changes when tensile strain is generated in monitoring unit 1, resulting in a change in resistance, the relationship between strain and the rate of change of resistance is correlated to obtain the resistance-strain conversion model. ; In the formula: To monitor the resistance change of unit 1 during the stretching process; The initial resistance of monitoring unit 1; For monitoring the tensile strain generated by unit 1; The sensitivity coefficient is denoted by , and the ambient temperature is denoted by . (°C) and loading strain rate (s) -1 bivariate function ;in, This is the temperature influence coefficient. The influence coefficient of the loading strain rate, These are fitting constants, all obtained through calibration experiments. In this embodiment, =-0.3509, =19.9430. Since the deformation rate during the failure development of soil and rock masses usually meets the quasi-static condition (loaded strain rate less than 0.0005 / s), it can be assumed that the above sensitivity coefficient is independent of the loaded strain rate. =0).

[0049] In this embodiment, the flexible conductive layer exhibits a tensile-sensitive effect, meaning its resistivity increases with increasing tensile strain. Therefore, a tensile-sensitive test is conducted to... , , Perform calibration.

[0050] Specifically, such as Figure 5 As shown, the monitoring unit 1 is placed inside the high and low temperature universal testing machine 6, and the monitoring unit 1 is connected to the multi-channel multimeter 7. The multi-channel multimeter is connected to the computer 8. The high and low temperature universal testing machine applies tensile force or shear force to the monitoring unit 1. The multi-channel multimeter collects the resistance signal, and the computer performs analysis and calculation. Then, the tensile conductivity characteristics of the monitoring unit 1 are tested, and the influence coefficients of temperature and loading strain rate on the sensitivity of the monitoring unit 1 are calibrated.

[0051] like Figure 5 As shown, a direct shear test was conducted on monitoring unit 1 inside a high and low temperature universal testing machine, thereby establishing the conversion relationship between monitoring unit 1 and soil shear displacement, and thus obtaining the strain-shear displacement model. ; In the formula: This represents the soil shear displacement. For monitoring segment length, The strain distribution function along the length of monitoring unit 1 is given by the measured tensile strain results from monitoring unit 1, since soil and rock typically undergo shear deformation along the sliding surface. Monitoring unit 1 is a one-dimensional flexible conductive strip (or grid) with multiple measuring electrodes 51 (i.e., multiple measuring points) arranged at equal (or unequal) intervals along its length. Each adjacent measuring electrode 51 constitutes a "sensing segment," with an initial resistance of... The real-time resistance is The rate of change of resistance in each sensing segment Combine the sensitivity coefficient of each sensing segment The average strain of that section can then be calculated. Then, through interpolation or finite element shape functions, a continuous strain distribution can be obtained. .

[0052] Although a coupling unit is set between monitoring unit 1 and the soil mass, the interfacial slippage between monitoring unit 1 and the soil mass still needs to be considered. Therefore, an interfacial coupling efficiency coefficient is introduced. To correct the discrepancy between strain measurements and actual soil shear displacement caused by interface slip, ensuring the accuracy of shear displacement calculation, a corrected strain-shear displacement model is obtained: ; In this embodiment, the interface coupling efficiency coefficient Calibration was achieved through direct shear tests. The values ​​are related to the type of soil and rock mass, water content, and overlying stress. Specifically, brittle soil and rock masses exhibit complete and coordinated interface coupling with the coupled units. =1; Cohesive soil and rock masses exhibit good coupling effects with coupled units. =0.7. For frictional soil and rock masses, due to their numerous internal pores, the coupling effect is related to water content and overlying stress, and the values ​​are taken from the table below.

[0053] Table 1. Values ​​of Coupling Efficiency Coefficients for Frictional Soil and Rock Masses

[0054] Understandably, the synergistic effect of the two models allows for accurate inference of the shear displacement of the soil and rock mass from the original resistance signal, providing a solid data foundation for subsequent early warning judgments.

[0055] In this embodiment, the multi-level early warning thresholds include a Level 1 warning value, a Level 2 warning value, and a Level 3 warning value. The Level 1 warning value corresponds to the pre-damage stage, the Level 2 warning value corresponds to the shear band expansion stage, and the Level 3 warning value corresponds to the macroscopic slip stage. It is understood that the Level 1 warning value is the smallest.

[0056] Example 3 This embodiment discloses a disaster monitoring system for soil and rock masses, including a data acquisition module, an analysis module, and an early warning module connected in sequence.

[0057] The acquisition module is used to monitor the deformation of the soil and rock mass, including multiple monitoring devices disclosed in Example 1, which are arranged in layers from the top of the slope to the bottom of the slope along the depth direction of the test area.

[0058] The analysis module incorporates the resistance-strain-shear displacement model disclosed in Example 2, which is used to receive and analyze the monitoring information from the acquisition module and output the shear displacement value.

[0059] The early warning module incorporates the multi-level early warning thresholds disclosed in Embodiment 2, which are used to receive the shear displacement value output by the analysis module and output an early warning signal alarm.

[0060] In this embodiment, the warning information includes the warning location, warning level, and handling measures. The warning location corresponds to the position of each measuring electrode 51 and the depth of the layer in which it is located.

[0061] The warning levels are divided into three levels based on the multi-level warning threshold: yellow warning, orange warning, and red warning, which correspond to the first-level warning value, the second-level warning value, and the third-level warning value, respectively.

[0062] The response measures are pre-set plans for different warning levels. For example, a yellow warning corresponds to the pre-damage stage, prompting monitoring personnel to pay closer attention and increase the monitoring frequency; an orange warning corresponds to the shear band expansion stage, prompting monitoring personnel to initiate an emergency investigation; and a red warning corresponds to the macro-slip stage, prompting monitoring personnel to organize the evacuation of all construction personnel.

[0063] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this 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 without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A geotechnical body catastrophe distributed flexible intelligent monitoring device, characterized in that, Includes monitoring unit and coupling unit; The monitoring unit includes a flexible conductive layer, a brittle conductive layer, and a circuit layer arranged sequentially from bottom to top within the encapsulation layer; The flexible conductive layer includes a first flexible substrate, a one-dimensional conductive material, and a two-dimensional conductive filler. The one-dimensional conductive material is overlapped into a network in the first flexible substrate, and the two-dimensional conductive filler is filled in the gaps of the one-dimensional conductive material. The brittle conductive layer is made of a conductive material with an intrinsic stiffness greater than a set value; The circuit layer includes a second flexible substrate, on which multiple measuring electrodes are arranged. Some measuring electrodes are connected to a flexible conductive layer, and some measuring electrodes are connected to a brittle conductive layer. The brittle conductive layer and the flexible conductive layer are connected in parallel. The coupling unit is wrapped around the outside of the monitoring unit and together they are filled into the soil and rock mass.

2. The distributed flexible intelligent monitoring device for soil and rock mass disasters as described in claim 1, characterized in that, The soil and rock mass includes frictional soil and rock mass, cohesive soil and rock mass, and brittle soil and rock mass; For frictional soil and rock masses, the coupling unit uses a material with good permeability and bonding properties; For cohesive soil and rock masses, the coupling unit uses a material with elasticity and bonding properties; For brittle rock and soil masses, the coupling unit uses grouting materials with strong permeability and consolidation capacity.

3. The distributed flexible intelligent monitoring device for soil and rock disasters as described in claim 1, characterized in that, A base layer is provided on the bottom surface of the flexible conductive layer, and the first flexible substrate, the second flexible substrate, and the encapsulation layer of the base layer are any one of polydimethylsiloxane, Ecoflex, and polyurethane.

4. The distributed flexible intelligent monitoring device for soil and rock mass disasters as described in claim 1, characterized in that, The one-dimensional conductive material is multi-walled carbon nanotubes, and the two-dimensional conductive material is graphene nanosheets, with a mass ratio of 1:3 to 3:

1.

5. The distributed flexible intelligent monitoring device for soil and rock mass disasters as described in claim 1, characterized in that, The thickness of the second flexible substrate is less than that of the first flexible substrate, and they are made of the same material.

6. A method for monitoring the catastrophic changes in rock and soil masses, characterized in that, The distributed flexible intelligent monitoring device for soil and rock disasters as described in any one of claims 1-5 is used, and the specific steps include: Determine the monitoring area and bury monitoring units in layers along the depth direction of the monitoring area; Before installation, select a coupling unit according to the type of soil and rock mass, and connect the monitoring unit to the acquisition equipment; The coupling unit is coated on the surface of the monitoring unit, and trenches or holes are excavated in layers in the monitoring area. The coupling unit is injected into the trenches or holes, and then the monitoring unit is placed in the trenches or holes. The acquisition device is equipped with a preset resistance-strain-shear displacement model and multiple warning thresholds. The acquisition device collects the monitoring signals from the monitoring unit and substitutes them into the model to output shear displacement values. The output shear displacement values ​​are compared with the preset multiple warning thresholds to output different warning signals.

7. A method for monitoring the catastrophic changes of rock and soil masses as described in claim 6, characterized in that, The monitoring units are laid in layers at set intervals along the depth direction. The monitoring frequency of the data acquisition equipment is as follows: the data acquisition interval is long under normal conditions, and the data acquisition interval is shortened when there is rainfall or changes in groundwater level. When abnormal fluctuations occur in the monitoring data, continuous and uninterrupted data collection is performed.

8. A method for monitoring the catastrophic changes of rock and soil masses as described in claim 6, characterized in that, The resistance-strain-shear displacement model includes a resistance-strain conversion model and a strain-shear displacement model; The resistance-strain conversion model is ; In the formula: To monitor the resistance change of the unit during the stretching process; The initial resistance of the monitoring unit; For monitoring the tensile strain generated by the unit; The sensitivity coefficient is denoted by , and the ambient temperature is denoted by . and loading strain rate bivariate function ;in, This is the temperature influence coefficient. The influence coefficient of the loading strain rate, These are fitting constants, all obtained through calibration experiments.

9. A method for monitoring the catastrophic changes of rock and soil masses as described in claim 8, characterized in that, The strain-shear displacement model is as follows: ; In the formula: This represents the soil shear displacement. For monitoring segment length, Let be the strain distribution function along the length of the monitoring unit; The coefficient for interface coupling efficiency is given by the equation, where brittle rock and soil mass is represented by the coefficient. =1, cohesive soil and rock mass =0.7, frictional soil and rock mass The values ​​are related to the type of soil and rock mass, water content, and overlying stress, and are determined through calibration tests.

10. A disaster monitoring system for rock and soil masses, characterized in that, The monitoring method described in any one of claims 6-9 includes a data acquisition module, an analysis module, and an early warning module connected in sequence. The data acquisition module includes multiple monitoring devices, which are arranged in layers along the depth direction of the test area; The analysis module has a built-in resistance-strain-shear displacement model, which is used to receive and analyze the monitoring information from the acquisition module and output the shear displacement value. The early warning module has built-in multi-level early warning thresholds, which are used to receive the shear displacement value output by the analysis module and output early warning signals.

Images