A real-time detection device for slope soil moisture content and landslide early warning method

Abstract

The invention discloses a real-time detection device for soil moisture content of a slope and a landslide early warning method. The detection device comprises a main control module, a power module and a plurality of detection modules installed at intervals on a detection rod. The main control module is electrically connected to the power module and the detection module respectively, and the main control module controls the detection operation of the detection module and collects detection information in real time. The detection module is installed below the ground surface along with the lower part of the detection rod, and the soil moisture content and compactness are accurately known through microwave phase measurement. When the slope has not actually deformed, landslided or displaced, the landslide of the slope can be early warned or predicted. The early warning has a larger advance warning amount, is highly real-time and timely, and can effectively reduce the loss of life and property of the people.

Description

Technical Field

[0001] The invention belongs to the technical field of geological monitoring, and in particular relates to a real-time detection device for slope soil moisture content and a landslide early warning method. Background Art

[0002] Mountain landslides, dam landslides and other slope landslides are common geological disasters. How to predict or prevent them in advance is an issue that the whole society, especially the industry and management departments at all levels, have long been concerned about and have worked hard to improve.

[0003] Existing early warning methods for slope landslides include video monitoring early warning, tilt deformation monitoring early warning, satellite remote sensing early warning, and satellite navigation (GPS, Beidou, etc.) displacement monitoring early warning. These early warning methods can only issue an alarm when the slope has actually deformed, landslided, or displaced. Even if the alarm is issued when the landslide just begins, it is difficult to guarantee more sufficient time for handling. If an early warning can be issued before a landslide occurs or before there are signs of a landslide, the loss of life and property of the people can be greatly reduced; even before there is a risk of a landslide, certain drainage and reinforcement measures can be taken to prevent the occurrence of a landslide. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects in the prior art and provide a real-time detection device for slope soil moisture content and a landslide early warning method by simultaneously measuring changes in soil moisture and compactness.

[0005] To achieve the above-mentioned purpose, the present invention designs a real-time detection device for slope soil moisture content, the detection device comprises a main control module, a power module and a plurality of detection modules installed at intervals on a detection rod, the main control module is electrically connected to the power module and the detection module respectively, the main control module controls the detection operation of the detection module and collects the detection information in real time; the detection module is installed below the ground surface along with the lower part of the detection rod; The detection module includes a first microstrip transmission line and a second microstrip transmission line installed on both sides of the support. The first microstrip transmission line is embedded in one side of the support through a microstrip line substrate, and the outer side of the first microstrip transmission line is filled with a hygroscopic material, and the hygroscopic material is in direct contact with the soil to be tested; the second microstrip transmission line is installed on the other side of the support or at a position that does not overlap with the first microstrip transmission line through a microstrip line substrate, and is in direct contact with the soil to be tested.

[0006] Furthermore, the main control module includes a microcontroller and a power communication circuit, and the detection module also includes a microwave generator, a power distributor, an electronic switch 1, an electronic switch 2 and a detection circuit; the detection circuit at least includes units such as a phase-sensitive detector, a low-pass filter, a microcontroller and a power communication circuit that are electrically connected in sequence; the power distributor is electrically connected to the microwave generator, the electronic switch 1 and the phase shifter, respectively, and is electrically connected to the phase-sensitive detector through the phase shifter; the microcontroller is connected to the microwave generator, the electronic switch 1 and the electronic switch 2, and controls the generation and shutdown of the microwave signal and the signal frequency setting, respectively, and controls the switching of the electronic switch at the same time, and the output signal of the electronic switch 1 is connected to the electronic switch 2 via the first microstrip transmission line and the second microstrip transmission line, and the output value of the electronic switch 2 is the phase-sensitive detector.

[0007] Furthermore, one end of the plurality of detection modules connected in series is electrically connected to the main control module, and specific connection signals include power supply signals (V+, G) and detection signals (RS485A, RS485B).

[0008] Furthermore, the detection device also includes a DTU (remote transmission unit) electrically connected to the main control module, and the power supply module includes a battery and / or a new energy power supply module such as wind and solar.

[0009] Furthermore, the microwave generator outputs a variable frequency signal of 200-960 MHz, and the power divider divides two signals in a 1:1 ratio, one of which is output to the first microstrip transmission line or the second microstrip transmission line, and the other is output to the phase shifter; the electronic switch includes a single-pole double-throw electronic switch.

[0010] Furthermore, the first microstrip transmission line and the second microstrip transmission line have the same conductor length, shape and material, and the second microstrip transmission line protrudes relative to the surface of the detection rod.

[0011] Furthermore, the microstrip line substrate includes non-metallic materials such as epoxy resin glass fiber board, PEEK (polyetheretherketone), polytetrafluoroethylene or polyimide to ensure that the microstrip transmission line independently transmits microwave signals, and the detection rod and support include metal materials such as steel, aluminum, copper, or rigid hard materials covered with metal materials.

[0012] Furthermore, the detection rod includes a plurality of extension tubes connected in sections, and the detection module is installed on the extension tube, or the detection module is installed between the extension tube and the detection rod, or between adjacent extension tubes.

[0013] On the other hand, a landslide early warning method uses any of the above-mentioned slope soil moisture content real-time detection devices to determine whether there is a landslide risk through layered joint detection of soil moisture content and compactness, and records that there are j=1,2,…, J points along the slope from top to bottom, and each point has i=1,2,…, I measuring points (detection modules) from top to bottom. The landslide early warning method includes at least one of a moisture content absolute value judgment method, a compactness absolute value judgment method, a moisture content / compactness joint judgment method, a moisture content change rate judgment method, and a compactness change rate judgment method; The absolute value determination method of moisture content includes: establishing a soil moisture content threshold matrix in, , ; When the measured value of moisture content at any time and any point , the system sends out an early warning signal; The absolute value determination method of compactness includes: establishing a soil compactness threshold matrix in, , ; When the compactness value at any time and any point is , the system sends out an early warning signal; The moisture content / compactness joint judgment method includes: establishing a soil moisture content and compactness joint threshold matrix in, , ; When the measured value of moisture content at any time and any point , and the measured value of compactness , the system sends out an early warning signal; The moisture content change rate judgment method includes: if the measured moisture content value exceeds the daily average value and shows an increasing trend for more than 10 consecutive sampling cycles or an increasing trend for more than 1 hour (the sampling cycle / interval is not less than 1 minute and not more than 30 minutes. For the above method, if the sampling interval is less than or equal to 6 minutes, one of the two judgment methods can be used), the system will issue an early warning signal; The method for judging the compactness change rate includes: if the compactness measured value is less than the daily average value and shows a decreasing trend for more than 10 consecutive sampling cycles or a decreasing trend for more than 1 hour (if the sampling interval is less than 6 minutes, one of the two judgment methods can be used), the system will issue an early warning signal; The method for obtaining the value of each element of the threshold matrix includes, generally based on experience or actual observation and test data, first determining the two boundary values ​​of the main diagonal, and then determining the values ​​of other elements according to the linear change law of rows and columns; note that the threshold values ​​of different slopes may be different, which is mainly related to the soil quality (clay, sand, etc.) and slope. The greater the slope, the smaller the moisture content threshold and the higher the compactness threshold.

[0014] The measured values ​​(including the measured values ​​of moisture content and the measured values ​​of compactness) include processed measured values, such as sliding window means, and the window size is not less than 3 consecutive sampling moments, that is, not less than 3 valid data.

[0015] Furthermore, the method also includes a calibration method for measuring moisture content and a calibration method for measuring compactness of the detection device; The moisture content measurement calibration method includes factory calibration of the detection module (detection unit on the detection device), by preparing soil with different moisture contents, burying the module therein, and basically reaching equilibrium after waiting for more than 10 minutes, and then recording the direct detection result of the detection device as the calibration value (the phase difference voltage value corresponding to the first microstrip transmission line), and establishing a corresponding relationship table (or database) including at least 2 or more different nominal moisture contents and the actual measured direct detection results of the detection module (such as the phase difference voltage), which is used for modeling and solving reasonable moisture content values ​​under any direct detection result; The compactness measurement calibration method includes compactness measurement calibration method 1 or compactness measurement calibration method 2; The first compactness measurement calibration method comprises: preparing at least two or more soil samples with different laboratory nominal moisture contents, burying the detection modules of the compactness measurement detection device to be calibrated therein one by one, performing calibration measurements under at least two groups of different pressures (corresponding to compactness) respectively, and obtaining the compactness standard value by using a standard soil compactness tester (such as Top Instruments TPJSD-750-V), waiting for more than 10 minutes to basically reach equilibrium, and then recording the direct detection result of the detection device as the calibration value (the phase difference voltage value corresponding to the second microstrip transmission line), establishing a corresponding relationship table (or database) including the actual measured direct detection results (phase difference voltage) of the detection device under at least two or more different nominal moisture contents and two or more different nominal compactnesses, and using the model to solve the corresponding soil compactness value under a known moisture content (the measurement result of the first microstrip transmission line) and any direct detection result; The second compactness measurement calibration method includes: for the detection device that measures the compactness of soil by dielectric constant, since the compactness of soils with different moisture contents is difficult to grasp, the second microstrip transmission line adopts the standard value calibration method under pure water and pure air conditions, that is, the corresponding relationship between the known dielectric constant and the measured direct detection result (phase difference voltage) is determined, and the consistency of the measurement is confirmed. During the field measurement, the change amount and / or change rate of the measurement result is mainly judged. When the measurement results of this method are used for landslide warning, the relative value of the dielectric constant or compactness is mainly paid attention to, and the absolute value is generally not paid attention to. This is a simple calibration method.

[0016] The advantages and beneficial effects of the present invention are as follows: the present invention utilizes the characteristics that the dielectric constants of soils with different moisture contents and different compactness are different, and the microwave transmission speeds are different in different dielectric constants (different transmission media), so that the phase difference with the reference signal is different, and the soil moisture content and compactness are accurately known through microwave phase measurement. The real-time detection device for slope soil moisture content of the present invention can simultaneously measure the soil moisture content and compactness in real time, and a landslide warning can be issued before the landslide actually occurs, normally several hours in advance or even more, because before a large-scale landslide occurs, there will generally be a small displacement or deformation (this is the method and content of traditional monitoring and early warning), and the soil moisture content and / or compactness will change significantly in advance before the small displacement or deformation occurs.

[0017] Therefore, the device and method of the present invention can warn or predict slope landslides before the slope actually deforms, slides or moves. The warning is more advanced and real-time, which can effectively reduce the loss of life and property of the people. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a device for real-time detection of soil moisture content in slopes according to the present invention; Figure 2 yes Figure 1 Schematic diagram of the detection module structure in FIG. Figure 3 It is the electrical connection schematic diagram of the detection module; Figure 4 It is a schematic diagram of the connection relationship between the main control module and the detection module.

[0019] Markings in the figure: 1. Main control module, 2. Power module, 3. Detection rod, 4. Detection module; 31. extension tube, 41. support member, 42. first microstrip transmission line, 43. second microstrip transmission line, 44. microstrip line substrate, 45. hygroscopic material. DETAILED DESCRIPTION

[0020] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0021] Embodiment 1: The present invention provides a real-time detection device for slope soil moisture content, such as Figure 1 As shown, the detection device includes a main control module 1, a power module 2 and a plurality of detection modules 4 installed at intervals on a detection rod 3. The main control module is electrically connected to the power module and the detection module respectively. The main control module controls the detection operation of the detection module and collects the detection information in real time. The detection module is installed below the ground surface along with the lower part of the detection rod. The main control module and small modules such as batteries can be independently installed near the detection rod, or installed on the top of the detection rod or in the top cavity. The main control module and the detection module are powered separately or jointly by new energy power supply modules, lithium batteries, etc.

[0022] like Figure 2 As shown, the detection module 4 includes a first microstrip transmission line 42 and a second microstrip transmission line 43 installed on both sides of a support 41. The first microstrip transmission line 42 is embedded in one side of the support through a microstrip line substrate 44, and the outer side of the first microstrip transmission line 42 is filled with a hygroscopic material 45, and the hygroscopic material 45 is in direct contact with the soil to be tested; the second microstrip transmission line 43 is installed on the other side of the support or at a position that does not overlap with the first microstrip transmission line through a microstrip line substrate 44, and is in direct contact with the soil to be tested.

[0023] During operation, the hygroscopic material on the surface of the first microstrip transmission line gradually forms a consistent moisture content with the surrounding soil. When the soil moisture increases, the hygroscopic material absorbs moisture from the soil until it reaches equilibrium with the soil. When the surrounding soil moisture decreases, water in the hygroscopic material is precipitated and eventually reaches equilibrium with the soil moisture. Therefore, the moisture content of the surrounding soil can be detected by detecting the moisture content of the hygroscopic material, and the moisture content data obtained is not affected by the compactness of the soil.

[0024] The second microstrip transmission line is in direct contact with the soil, and its detection data is affected not only by the moisture content of the surrounding soil, but also by the compactness of the soil. When the moisture content of the surrounding soil remains unchanged and the compactness increases, the soil density around the second microstrip transmission line increases, and the moisture content per unit volume increases, so its detection results will change.

[0025] The basic principle is that due to the different external medium environments of the transmission lines, their dielectric constants are different. According to the microwave transmission principle: Wherein, c is the speed of light, ε is the mixed dielectric constant, and μ is the magnetic permeability. The magnetic permeability of 1 can be ignored, so the transmission speed of microwaves depends on the dielectric constant of the medium. Since the reference signal of the present invention uniformly adopts the original signal of the power divider, the difference in the dielectric constant of the transmission line on the measurement side leads to different microwave transmission speeds and transmission paths. Different transmission speeds / paths lead to different phase shifts and / or amplitudes of microwave signals. Therefore, by detecting and comparing the phases and amplitudes of the two microwave signals of the measurement signal and the reference signal, and outputting different detection voltage signals, the relative change of the dielectric constant can be obtained, and the relative change of the medium concentration (water content or compactness) can be obtained through the relative change of the dielectric constant.

[0026] In summary, the moisture content of the surrounding soil can be directly detected through the first microstrip transmission line, and it is not affected by the compactness; the second microstrip transmission line is affected by both the moisture content and the compactness. By analyzing the data of the second microstrip transmission line, the change in compactness can be obtained. The soil moisture content is too high or the change rate is too large, or the soil becomes loose (the compactness decreases), or the moisture content and compactness change too much at the same time, etc., which may cause landslides. When the soil moisture content and compactness change, displacement and deformation may not occur, that is, early warning information can be obtained earlier before the landslide occurs. Therefore, the joint monitoring of the two, compared with the traditional displacement or deformation monitoring, can obtain landslide warning signals in advance, which is conducive to disposal and response, and can effectively reduce the loss of life and property of the people.

[0027] Preferably, Figure 3 As shown, the main control module includes a microcontroller and a power communication circuit (not shown in the main control module figure), and the detection module also includes a microwave generator, a power distributor, an electronic switch 1, an electronic switch 2 and a detection circuit; the detection circuit at least includes a phase-sensitive detector, a low-pass filter, a microcontroller and a power communication circuit and other units electrically connected in sequence; the power distributor is electrically connected to the microwave generator, the electronic switch 1 and the phase shifter respectively, and is electrically connected to the phase-sensitive detector through the phase shifter; the microcontroller is connected to the microwave generator, the electronic switch 1 and the electronic switch 2, and controls the generation and shutdown of the microwave signal and the signal frequency setting respectively, and controls the switching of the electronic switch at the same time, and the output signal of the electronic switch 1 (No, Nc in the figure) is connected to the electronic switch 2 via the first microstrip transmission line 42 and the second microstrip transmission line 43 respectively, and the output value of the electronic switch 2 is the phase-sensitive detector.

[0028] The circuit of each detection module is the same. The microwave signal generator generates a microwave signal of a fixed frequency and transmits it to the power divider. The power divider outputs two microwave signals with the same power and phase, of which the power divider out1 signal is output to the com end of the electronic switch 1. The electronic switch 1 is a single-pole double-throw type. The normally open No end of the electronic switch 1 is connected to the first microstrip transmission line, and the normally closed Nc end is connected to the second microstrip transmission line. The electronic switch 2 is also a single-pole double-throw type, with its normally open No end connected to the first microstrip transmission line and its normally closed Nc end connected to the second microstrip transmission line. It can also be exchanged, with the normally open end connected to the second microstrip transmission line and the normally closed end connected to the first microstrip transmission line. In short, the two microstrip transmission lines transmit microwave signals in turn. The com end of the electronic switch 2 is connected to the in1 end of the phase-sensitive detector. The out2 signal of the power divider is output to the phase shifter, and the output of the phase shifter is connected to the in2 end of the detector. The output of the phase-sensitive detector is connected to the input of the low-pass filter, and the output of the low-pass filter is connected to the AD port of the microcontroller.

[0029] In this embodiment, the main control module controls each detection module in turn to take samples, and the moisture content and compactness of different underground locations can be obtained. In essence, each detection module is designed to work independently, that is, each detection module is equipped with an independent power distributor, microwave generator, phase-sensitive detector, low-pass filter, microcontroller, power communication circuit and other units, which can be detected independently, while the main control module mainly retains the control, data acquisition and external communication functions, that is, the main control module and the detection module are designed with microcontrollers respectively, and information is exchanged through the communication circuit. The detection module of this design can work independently, and the main control module and the detection module are convenient to connect, but the functional circuits of the detection module are repeated.

[0030] In fact, the main control module and the detection module can share the microcontroller of the main control module. In this case, the communication interface needs to be adapted, and the control logic of a single main control module needs to adapt to actual detection requirements.

[0031] In addition, in principle, the detection module only needs a microstrip transmission line, that is to say, other circuit units including microwave generators, power dividers and detection circuits can be designed on the main control module, that is, all detection modules share circuit units such as microwave transmission and reception detection. However, this design has high requirements for the implementation of microwave transmission circuit design, because the transmission requirements of high-frequency signals and low-frequency signals are different, and there are multiple microwave transmission channels on the same detection device. The hardware is complex, the cost is high, the debugging is difficult, and the circuit performance is greatly affected by the environment. Therefore, this design is rarely used in engineering.

[0032] The microcontroller outputs a control signal to control the microwave signal frequency and / or the generation and shutdown of the microwave signal of the microwave generator, and simultaneously controls the working states of the electronic switch 1 and the electronic switch 2. When the microcontroller controls the two electronic switches to be in the normally open state at the same time, the microwave signal output by the power divider out1 is connected to the first microstrip transmission line through the electronic switch 1, and then passes through the electronic switch 2 to the phase-sensitive detector, and the phase is compared with the microwave signal passing through the phase shifter. The phase difference signal is detected by the microcontroller to obtain the detection signal on the first microstrip transmission line. When the microcontroller controls the two electronic switches to be in the normally closed state at the same time, the microwave signal output by the power divider out1 is connected to the second microstrip transmission line through the electronic switch 1, and then passes through the electronic switch 2 to the phase-sensitive detector, and the phase is compared with the microwave signal passing through the phase shifter. The phase difference signal is detected by the microcontroller to obtain the detection signal on the second microstrip transmission line. The two microstrip transmission lines adopt a time-sharing detection method.

[0033] The function of the phase shifter is to adjust the output of the phase-sensitive detector to the most appropriate range, so as to facilitate the detection and processing by the microcontroller.

[0034] The change in moisture content or compactness of the soil around the first microstrip transmission line and the second microstrip transmission line will affect its dielectric constant, thereby affecting the phase change on each detection circuit. The dielectric constant of each surrounding medium can be obtained through the phase difference signal output by the phase-sensitive detector. The dielectric constant value obtained from the first microstrip transmission line can directly calculate the moisture content of the soil. The dielectric constant value obtained on transmission line 2 can obtain data information related to compactness after correction processing.

[0035] In fact, it is also possible to design a circuit for simultaneous detection of two microstrip transmission lines, such as a power divider that simultaneously outputs four signals, two of which are used for the first microstrip transmission line and its corresponding phase shifter, phase-sensitive detection and low-pass filtering, and the other two are used for the second microstrip transmission line and its corresponding phase shifter, phase-sensitive detection and low-pass filtering. However, this design consumes more power and has a higher cost.

[0036] Preferably, Figure 4 As shown, after a plurality of detection modules are connected in series, one end is electrically connected to the main control module. The specific connection signals include power supply signals (V+, G) and detection signals (RS485A, RS485B). The number of detection modules described in the present invention is between 1 and 16. The upper limit of the number is mainly set to consider the performance of the serial communication interface and the signal quality requirements. The specific number also needs to consider the soil quality of the measuring point, the slope size, the maximum burial depth, the networking density (including the upper and lower intervals of the detection modules and the intervals between different measuring points) and other requirements; Figure 4From a structural point of view, the main control module and each detection module are connected in series, but from a circuit principle point of view, the main control module and each detection module are connected in parallel; although in principle it is also possible to structurally realize a parallel connection between the main control module and each detection module, the wiring and interface are complex and it is rarely used in actual projects.

[0037] Preferably, the microwave generator outputs a variable frequency signal of 200-960 MHz, and the power divider divides two signals in a 1:1 ratio, one of which is output to the first microstrip transmission line 42 or the second microstrip transmission line 43, and the other is output to the phase shifter; the electronic switch includes a single-pole double-throw electronic switch.

[0038] In principle, it is not necessary for the two powers and / or phases to be consistent, nor is it necessary for the conductor lengths, shapes, and materials of the two transmission lines to be consistent, or for the substrates on both sides to be completely consistent. For inconsistent situations, it is only necessary to calibrate the value relationship in advance, but the implementation is more cumbersome. The design of this embodiment to be consistent is more convenient and simple for measurement and calculation processing, which is also a reasonable choice in actual engineering applications.

[0039] Preferably, the first microstrip transmission line 42 and the second microstrip transmission line 43 have the same conductor length, shape and material, and the second microstrip transmission line matches the surface of the detection rod and does not protrude from the surface, which is convenient for installation and transportation.

[0040] Preferably, the microstrip line substrate 44 includes non-metallic materials such as epoxy resin glass fiber board, PEEK (polyetheretherketone), polytetrafluoroethylene or polyimide to ensure that the microstrip transmission line independently transmits microwave signals. The detection rod 3 and the support member 41 include metal materials such as steel, aluminum, copper, or rigid hard materials covered with metal materials to ensure that the microstrip transmission line is measured under a temperature environment basically the same as the surrounding soil. The metal shell also has a common grounding function to provide better protection for the circuit. Therefore, the insulation between the microstrip transmission line and the metal shell must be done well; the transmission line includes copper wire, silver wire, etc.; the hygroscopic material includes hygroscopic ceramics, wood, mineral desiccant, silica gel desiccant, montmorillonite, hygroscopic plastic resin, polymer hygroscopic resin, natural cotton and linen fiber, etc.

[0041] Preferably, the detection modules are mounted on the detection rod at a certain interval, and the specific intervals are set according to the monitoring requirements of the actual measured points.

[0042] The detection rod, support member (corresponding to the detection module) and the extension tube that may be used later include a cylindrical or cylindrical component, or a cylindrical or cylindrical component covered with a metal shell; the installation methods include fitting, mounting, screwing, etc. For example, for the cylindrical component, the support member can be fitted or partially mounted on the detection rod or the extension tube, and a corresponding mounting slot is set at the corresponding installation position on the detection rod, and the upper and lower ends of the support member are respectively provided with mounting interfaces for fitting with the detection rod or the extension tube, such as a buckle or a fixing screw hole, etc.; or the support member (corresponding to the detection module) is connected in sections to the detection rod and the extension tube and between adjacent extension tubes, and the upper and lower connecting ports of the detection rod and the extension tube, and the upper and lower ends of the support member are respectively provided with mutually connected mounting interfaces, such as bolts and / or screw holes.

[0043] The transmission line of this embodiment adopts a silver wire with a diameter of 1.5mm and a length of 30mm, and the base material is polytetrafluoroethylene. The detection rod and the support are both made of stainless steel tubes. The detection modules are mounted on the detection rod at a certain distance. The main control module is installed inside the top of the detection rod. The detection module is buried deep underground with the detection stem. Three detection modules are arranged on the detection rod, among which the first detection module is 0.5m below the surface, and the subsequent detection modules are arranged at intervals of 1m in sequence; the power module is also provided with a solar panel and a lithium battery pack, which are installed near the monitoring point; the center frequency of the microwave generator is 330MHz (common center frequencies also include 500MHz, 750MHz, etc.), and the bandwidth is 1 MHz.

[0044] Embodiment 2: The difference from Example 1 is that the transmission line and substrate of this embodiment are formed by etching a copper-clad laminate, wherein the microstrip transmission line has a width of 2 mm and a length of 30 mm, the substrate is the substrate of the copper-clad laminate, and the support member 41 is a hard plastic cylindrical structure covered with a stainless steel shell.

[0045] Embodiment 3: The difference from Example 1 is that the detection device also includes a DTU (remote transmission device) electrically connected to the main control module, and the power module includes a battery and a wind-solar combination new energy power supply module. Wind power generation and solar panels during the day not only power the system, but also charge the lithium battery. When the new energy supply is insufficient, the lithium battery directly powers the system. The main control module is connected to the DTU remote transmission device through TX and RX communication signals, and transmits the detection data to the remote server and / or centralized monitoring system.

[0046] Embodiment 4: The difference from Example 1 is that the second microstrip transmission line is convex relative to the surface of the detection rod, which is conducive to better contact with the surrounding soil and sensing soil pressure, but the protrusion should not be too large to avoid damaging the microstrip transmission line when the detection rod is installed.

[0047] Embodiment 5: The difference from Example 1 is that the detection rod includes a plurality of extension tubes 31 connected in sections, and detection modules 4 are installed between the extension tubes and the detection rods and between adjacent extension tubes, so that the number of detection modules can be increased or decreased according to the needs of field monitoring, and the extension tubes include metal materials such as steel, aluminum, copper, or rigid hard materials covered with metal materials. In this embodiment, the detection rod, the support member (detection module) and the extension tube are connected by screwing to form a complete detection rod that penetrates into the soil at the measuring point. In fact, the detection module can also be installed on the extension tube, and the extension tubes are connected one by one. There are many specific implementation methods, which will not be described one by one.

[0048] Embodiment 6: A landslide early warning method, using any of the above-mentioned slope soil moisture real-time detection devices or other devices for measuring soil moisture and compactness, through layered joint detection of soil moisture and compactness, to determine whether there is a landslide risk, recording that there are j=1,2,…, J points from top to bottom along the slope, and each point has i=1,2,…, I measuring points (detection modules) from top to bottom. The landslide early warning method includes at least one of a moisture content absolute value judgment method, a compactness absolute value judgment method, a moisture content / compactness joint judgment method, a moisture content change rate judgment method, and a compactness change rate judgment method; The absolute value determination method of moisture content includes: establishing a soil moisture content threshold matrix in, , ; When the measured value of moisture content at any time and any point , the system sends out an early warning signal; The absolute value determination method of compactness includes: establishing a soil compactness threshold matrix in, , ; When the compactness value at any time and any point is , the system sends out an early warning signal; The moisture content / compactness joint judgment method includes: establishing a soil moisture content and compactness joint threshold matrix in, , ; When the measured value of moisture content at any time and any point , and the measured value of compactness , the system sends out an early warning signal; The method for judging the moisture content change rate includes: when the measured moisture content exceeds the daily average and shows an increasing trend for more than 10 consecutive sampling periods or more than 1 hour (the sampling period / interval is not less than 1 minute and not more than 30 minutes. For the above method, if the sampling interval is less than or equal to 6 minutes, one of the two judgment methods can be used), the system sends out an early warning signal; setting more than 10 consecutive sampling periods / intervals is mainly due to the consideration that soil moisture content and compactness are a long-term scale variation. At the same time, in order to avoid the influence of noise, a certain number of measurement results for a certain period of time should be observed continuously, and analysis and judgment should be carried out; when setting the sampling interval, it is not meaningful to set it too small, but it is not meaningful to set it too small. If the sampling interval is too long, it will lose real-time performance. Generally, it is more than 1 minute. If conditions permit, a smaller sampling interval of 1 minute or 2 minutes is used. Therefore, it is advisable to continuously sample for more than 10 cycles to judge the trend of change. Of course, it can also be set to more than 20 cycles. If the sampling interval is longer, such as sampling once every half an hour, it is not advisable to wait for 10 cycles, and judgment is required after 2 consecutive cycles. If a longer sampling period is set in the project, it is generally required that the noise of each measurement value is small, that is, the accuracy of a single measurement result is high, and it can be used directly to judge the change situation. A smaller sampling period can reduce this requirement, and the noise impact can be ignored in multiple continuous samplings. The sampling period of this embodiment is 2 minutes. The following principles and principles of the compactness change rate judgment method are the same.

[0049] The method for judging the compactness change rate includes: if the compactness measured value is less than the daily average value and shows a decreasing trend for more than 10 consecutive sampling cycles or a decreasing trend for more than 1 hour (if the sampling interval is less than 6 minutes, one of the two judgment methods can be used), the system will issue an early warning signal; The method for obtaining the value of each element of the threshold matrix includes, generally based on experience or actual observation and test data, first determining the two boundary values ​​of the main diagonal, and then determining the values ​​of other elements according to the linear change law of rows and columns; note that the threshold values ​​of different slopes may be different, which is mainly related to the soil quality (clay, sand, etc.) and slope. The greater the slope, the smaller the moisture content threshold and the higher the compactness threshold.

[0050] This embodiment takes I=3, J=5 as an example, and sets The unit of compactness is Kpa (kilopascal); It should be noted that the threshold matrix and the sensor (detection module) layout do not need to be completely consistent. When there is no measuring point sensor at the corresponding (i, j) point, it does not affect the setting of the threshold matrix acquisition value of the point. The actual measured value is empty (no comparison) during comparison and judgment.

[0051] The measured values ​​(including the measured values ​​of moisture content and the measured values ​​of compactness) include processed measured values, such as sliding window means, and the window size is not less than 3 consecutive sampling moments, that is, not less than 3 valid data.

[0052] The above is only the premise of landslide monitoring equipment or system warning. After a single measuring point warning occurs, it is generally necessary to pay attention to the continuous changes of adjacent points (including the data of each detection module on the same detection rod) before deciding on further measures.

[0053] Preferably, the method further comprises a calibration method for measuring moisture content and a calibration method for measuring compactness of the detection device; The moisture content measurement calibration method includes factory calibration of the detection module (detection unit on the detection device), by preparing soil with different moisture contents, burying the module therein, and basically reaching equilibrium after more than 10 minutes, and then recording the direct detection result of the detection device as the calibration value (the phase difference voltage value corresponding to the first microstrip transmission line), and establishing a corresponding relationship table (or database) including at least 2 or more different nominal moisture contents and the direct detection results (such as phase difference voltage) measured by the detection module, which is used for model interpolation to solve the reasonable moisture content value under any direct detection result; this embodiment tests soil samples with moisture contents of 0, 0.1, 0.2, 0.3, 0.4, and 0.5 respectively based on the minimum moisture content of 0 and the maximum moisture content of 50%. The soil samples are taken from the mountain. Generally, soil samples can be taken from the mountain or slope to be measured before the equipment is installed, and test samples with different moisture contents can be re-made for calibration.

[0054] The compactness measurement calibration method includes compactness measurement calibration method 1; The first compaction measurement calibration method comprises: preparing at least two soil samples with different laboratory nominal moisture contents, embedding the detection modules of the compaction measurement detection device to be calibrated into the samples one by one, performing calibration measurements under at least two groups of different pressures (corresponding to compaction), and using a standard soil compaction tester (such as Top Instruments TPJSD-750 -V) to obtain the compactness standard value, wait for more than 10 minutes to basically reach equilibrium, then record the direct detection result of the detection device as the calibration value (the phase difference voltage value corresponding to the second microstrip transmission line), and establish a corresponding relationship table (or database) including at least 2 or more different nominal moisture contents and 2 or more different nominal compactions of the direct detection results (phase difference voltage) of the detection device, which is used to solve the model for the known moisture content (the measurement result of the first microstrip transmission line) and the corresponding soil compactness value under any direct detection result; this embodiment tests soil samples with moisture contents of 0, 0.1, 0.2, 0.3, 0.4, and 0.5 respectively based on the minimum moisture content of 0 and the maximum moisture content of 50%, and each soil sample is subjected to calibration tests under multiple compactions of 100 MPa, 50 MPa, 1 MPa, 600 kPa, 500 kPa, 400 kPa, 300 kPa, 200 kPa, 100 kPa, etc.

[0055] Embodiment 7: The difference from Example 6 is that the compactness measurement calibration method includes compactness measurement calibration method 2.

[0056] The second compactness measurement calibration method includes: for the detection device that measures the compactness of soil by dielectric constant, since the compactness of soils with different moisture contents is difficult to grasp, the second microstrip transmission line adopts the standard value calibration method under pure water and pure air conditions, that is, the corresponding relationship between the known dielectric constant and the measured direct detection result (phase difference voltage) is determined, and the consistency of the measurement is confirmed. During the field measurement, the change amount and / or change rate of the measurement result is mainly judged. When the measurement results of this method are used for landslide warning, the relative value of the dielectric constant or compactness is mainly paid attention to, and the absolute value is generally not paid attention to. This is a simple calibration method.

[0057] The above description is only part of the relatively systematic and comprehensive embodiments of the real-time detection device for slope soil moisture content and compactness and the landslide warning method of the present invention. In fact, there can be many kinds of configurations of the detection rod, the division method of the main control module and the detection module, the module installation structure, and especially the installation method of the detection module relative to the detection rod or the extension tube. The specific landslide warning judgment method can also use the moisture content, compactness measured value and change rate for joint judgment, etc., all of which belong to the protection scope of the present invention and will not be listed one by one here.

Claims

1. A real-time detection device for slope soil moisture content, characterized in that: The detection device comprises a main control module (1), a power module (2) and a plurality of detection modules (4) installed at intervals on a detection rod (3); the main control module is electrically connected to the power module and the detection module respectively, and the main control module controls the detection operation of the detection module and collects detection information in real time; the detection module is installed below the ground surface along with the lower part of the detection rod; The detection module (4) comprises a first microstrip transmission line (42) and a second microstrip transmission line (43) installed on both sides of a support member (41); the first microstrip transmission line (42) is embedded in one side of the support member through a microstrip line substrate (44); a hygroscopic material (45) is filled on the outside of the first microstrip transmission line (42); the hygroscopic material (45) is in direct contact with the soil to be tested; and the second microstrip transmission line (43) is installed on the other side of the support member or at a position not overlapping with the first microstrip transmission line through a microstrip line substrate (44), and is in direct contact with the soil to be tested.

2. A device for real-time detection of slope soil moisture content according to claim 1, characterized in that: The main control module (1) comprises a microcontroller and a power supply communication circuit, and the detection module further comprises a microwave generator, a power distributor, an electronic switch 1, an electronic switch 2 and a detection circuit; the detection circuit at least comprises a phase-sensitive detector, a low-pass filter, a microcontroller and a power supply communication circuit unit which are electrically connected in sequence; the power distributor is electrically connected to the microwave generator, the electronic switch 1 and the phase shifter respectively, and is electrically connected to the phase-sensitive detector via the phase shifter; the microcontroller is connected to the microwave generator, the electronic switch 1 and the electronic switch 2, and the output signal of the electronic switch 1 is connected to the electronic switch 2 via the first microstrip transmission line (42) and the second microstrip transmission line (43) respectively, and the output value of the electronic switch 2 is connected to the phase-sensitive detector.

3. A real-time detection device for slope soil moisture content according to claim 1, characterized in that: One end of the plurality of detection modules connected in series is electrically connected to the main control module, and specific connection signals include a power supply signal and a detection signal.

4. A device for real-time detection of slope soil moisture content according to claim 1, characterized in that: The detection device also includes a DTU electrically connected to the main control module, and the power supply module includes a battery and / or a new energy power supply module.

5. The device for real-time detection of soil moisture content in slope according to claim 1, characterized in that: The microwave generator outputs a variable frequency signal of 200-960 MHz, and the power distributor divides two signals in a 1:1 ratio, one of which is output to the first microstrip transmission line (42) or the second microstrip transmission line (43), and the other is output to the phase shifter; the electronic switch comprises a single-pole double-throw electronic switch.

6. A device for real-time detection of slope soil moisture content according to claim 1, characterized in that: The first microstrip transmission line (42) and the second microstrip transmission line (43) have the same conductor length, shape and material, and the second microstrip transmission line is convex relative to the surface of the detection rod.

7. A device for real-time detection of slope soil moisture content according to claim 1, characterized in that: The microstrip line substrate (44) comprises epoxy resin glass fiber board, PEEK, polytetrafluoroethylene or polyimide non-metallic material, and the detection rod (3) and the support member (41) comprise metal material, or a rigid hard material covered with metal material.

8. A device for real-time detection of slope soil moisture content according to claim 1, characterized in that: The detection rod comprises a plurality of extension tubes (31) connected in sections, and a detection module (4) is installed on the extension tube (31), or the detection module (4) is installed between the extension tube and the detection rod, or between adjacent extension tubes.

9. A landslide early warning method, characterized in that: By combining soil moisture content and compactness in layers, it is determined whether there is a landslide risk. It is recorded that there are j=1,2,…,J points along the slope from top to bottom, and each point has i=1,2,…,I measuring points from top to bottom. The landslide early warning method includes at least one of a moisture content absolute value judgment method, a compactness absolute value judgment method, a moisture content / compactness combined judgment method, a moisture content change rate judgment method, and a compactness change rate judgment method. The absolute value determination method of moisture content includes: establishing a soil moisture content threshold matrix 10. Among them, , ; When the measured value of moisture content at any time and any point , the system sends out an early warning signal; The absolute value determination method of compactness includes: establishing a soil compactness threshold matrix 11. Among them, , ; When the compactness value at any time and any point is , the system sends out an early warning signal; The moisture content / compactness joint judgment method includes: establishing a soil moisture content and compactness joint threshold matrix 12. Among them, , ; When the measured value of moisture content at any time and any point , and the measured value of compactness , the system sends out an early warning signal; The method for judging the rate of change of moisture content includes: if the measured value of moisture content exceeds the daily average value and shows an increasing trend for more than 10 consecutive sampling cycles or an increasing trend for more than 1 hour, the system will issue an early warning signal; The method for judging the rate of change of compactness includes: if the measured value of compactness is less than the daily average value and shows a decreasing trend for more than 10 consecutive sampling cycles or a decreasing trend for more than 1 hour, the system issues an early warning signal; The method for obtaining the values ​​of each element of the threshold matrix includes first determining two boundary values ​​of the main diagonal, and then determining other element values ​​according to the linear change law of rows and columns; The measured value includes a sliding window mean, and the window size is not less than 3 consecutive sampling moments.

13. A landslide early warning method according to claim 9, characterized in that: The method also includes a moisture content measurement calibration method and a compactness measurement calibration method for the detection device; The moisture content measurement calibration method includes factory calibration of the detection module, by preparing soil with different moisture contents, burying the module therein, waiting for more than 10 minutes, and then recording the direct detection result of the detection device as the calibration value, and establishing a corresponding relationship table including at least 2 or more different nominal moisture contents and the direct detection results actually measured by the detection module, which is used to solve the reasonable moisture content value under any direct detection result by model; The compactness measurement calibration method includes compactness measurement calibration method 1 or compactness measurement calibration method 2; The first compactness measurement calibration method comprises: preparing at least two or more soil samples with different laboratory nominal moisture contents, burying the detection modules of the compactness measurement detection device to be calibrated therein one by one, performing at least two groups of calibration measurements under different pressures respectively, and obtaining the compactness standard value using a standard soil compactness tester, and then recording the direct detection result of the detection device as the calibration value after waiting for more than 10 minutes, and establishing a corresponding relationship table of the actual measured direct detection results of the detection device under at least two or more different nominal moisture contents and two or more different nominal compactnesses, which is used for modeling the soil compactness value under known moisture content and any direct detection result; The second compactness measurement calibration method includes: for a detection device that measures soil compactness by dielectric constant, a standard value calibration method is used under pure water and pure air conditions, that is, the corresponding relationship between the dielectric constant and the actual direct detection result is determined, and the consistency of the measurement is confirmed. During field measurement, the change amount and / or change rate of the measurement result is mainly judged.

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