Frozen soil ice crystal migration testing device and method based on capacitance measurement

Abstract

The invention relates to a frozen soil ice crystal migration testing device and method based on capacitance measurement. The device comprises a scanning annular capacitance sensor which can be vertically and movably nested on a to-be-tested piece and is provided with a plurality of detection electrodes; the data acquisition module is connected to the detection electrode and acquires capacitance data through the switch array; the data processing module generates a fluctuation diagram of the total capacitance value of each section of the to-be-tested piece according to the capacitance data and displays the fluctuation diagram in the vertical direction; and the ice crystal identification module determines the ice crystal surface position according to the fluctuation diagram. Compared with the prior art, the method has the advantages of non-radioactivity, non-invasiveness, rapidness and low cost, can realize visual detection of ice crystal migration in frozen soil, and has the characteristics of rapid response, economy and safety.

Description

Technical Field

[0001] The invention relates to a method for testing ice crystals inside frozen soil, and in particular to a device and method for testing the migration of ice crystals in frozen soil based on capacitance measurement. Background Art

[0002] In the field of meteorology, winter frozen soil monitoring is of great significance for understanding climate change, predicting extreme weather events, and assessing the stability of infrastructure. However, at present, meteorological departments mainly rely on traditional Danilin frozen soil devices or manual digging methods for frozen soil detection. These methods are not only inefficient, but also unable to achieve automatic observation of frozen soil, limiting the comprehensiveness of ground meteorological observation and disaster warning systems. In addition, there are also deficiencies in the frozen soil testing equipment in the laboratory. The existing testing methods often focus on engineering practice and lack sufficient scientific data support, which limits the ability to deeply understand the characteristics of frozen soil.

[0003] Frozen soil is a complex medium composed of ice, water and soil particles. The migration of ice crystals inside it has a significant impact on the soil structure and mechanical properties. However, existing frozen soil detection technology cannot effectively capture the dynamic process of ice crystal migration, resulting in limited understanding of frozen soil behavior.

[0004] Therefore, there is an urgent need to develop a testing device and method that can realize visual detection of ice crystal migration inside permafrost, and at the same time has the characteristics of rapid response and economic safety, which is of great scientific and practical significance for improving the level of permafrost research and monitoring. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a frozen soil ice crystal migration test device and method based on capacitance measurement, which has the advantages of being non-radioactive, non-invasive, fast and low-cost, can realize the visual detection of ice crystal migration inside frozen soil, and has the characteristics of rapid response and economic safety.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] The first aspect of the present invention provides a frozen soil ice crystal migration test device based on capacitance measurement, comprising a scanning annular capacitance sensor, a data acquisition module, a data processing module, and an ice crystal identification module, wherein specifically:

[0008] A scanning annular capacitive sensor can be mounted on a test object and can move vertically relative to the test object. A plurality of detection electrodes are arranged on the scanning annular capacitive sensor. The test object is a frozen soil sample.

[0009] A data acquisition module, connected to the detection electrode through a switch gating array, the data acquisition module is used to obtain capacitance data of the scanning annular capacitance sensor during movement, the capacitance data including capacitance values ​​at multiple cross sections;

[0010] The data processing and identification module is used to generate a capacitance total value fluctuation diagram of different cross sections of the test piece according to the capacitance data, display it in the vertical direction, and determine the position of the ice crystal surface, that is, the peak value of the total capacitance, according to the capacitance total fluctuation diagram.

[0011] Furthermore, the scanning annular capacitive sensor includes a hollow cylindrical base, a fixed lower chassis, an edge shield, and an external shield.

[0012] Further, the hollow cylindrical base is mounted on the fixed lower chassis;

[0013] A plurality of detection electrodes are arranged on the outer surface of the base.

[0014] Furthermore, the edge shield is in a ring shape and covers both ends of each detection electrode to reduce the electric field distortion at the edge of the sensor and ensure uniform electric field distribution;

[0015] The external shield is ring-shaped, and is wrapped around the outside of each detection electrode. The external shield extends in the length direction to cover the base, thereby reducing external electromagnetic interference.

[0016] Furthermore, the fixed lower chassis is provided with radial threaded holes, and the radial threaded holes are used to fix the scanning annular capacitive sensor on the test piece.

[0017] Furthermore, the hollow cylindrical base and the fixed lower chassis are both made of insulating materials.

[0018] Furthermore, insulating materials are provided between the edge shield, the external shield and the detection electrode;

[0019] The detection electrode, edge shielding and external shielding are all made of conductive metal.

[0020] Furthermore, the detection electrode is evenly fixed to the middle of the outer surface of the hollow cylindrical base.

[0021] A second aspect of the present invention provides a frozen soil ice crystal migration test method using the above-mentioned test device, comprising the following steps:

[0022] Obtaining capacitance values ​​at each cross section of the test piece from the detection electrode;

[0023] Calculating the total capacitance value of each cross section based on the acquired capacitance value, and generating a fluctuation diagram of the total value along the vertical direction;

[0024] The maximum position of the total capacitance, that is, the position of the ice crystal surface inside the frozen soil, is determined based on the fluctuation diagram.

[0025] A second aspect of the present invention provides a storage medium comprising computer executable instructions, which, when executed by a computer processor, is used to perform the soil ice crystal migration test method as described above.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The present invention innovates the traditional fixed electrode measurement mode by embedding a scanning annular capacitive sensor into the frozen soil specimen and moving it vertically. This method only requires a small number of detection electrodes to measure multiple cross sections, thereby saving costs and improving efficiency.

[0028] (2) The present invention measures the capacitance value of each cross section and calculates the total capacitance value of each cross section to generate a graph showing the change of the total capacitance value along the vertical direction. This method makes the detection result more intuitive and can quickly determine the approximate position of the internal ice crystal layer.

[0029] (3) The present invention adopts a scanning annular capacitance sensor for capacitance acquisition, which has the characteristics of low cost and economical affordability, while reducing the detection cost and ensuring economy and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structure of the ice crystal migration test device inside frozen soil of the present invention;

[0031] Figure 2 It is a structural schematic diagram of the scanning annular capacitive sensor of the present invention;

[0032] Figure 3 It is a schematic diagram of the process of the ice crystal migration test characterization method in frozen soil of the present invention;

[0033] Figure 4 This is a schematic diagram of the vertical movement measurement of ice crystals in frozen soil according to the present invention;

[0034] Figure 5 This is a case diagram of ice crystal identification inside frozen soil of the present invention;

[0035] In the figure: 100, scanning annular capacitive sensor; 101, hollow cylindrical base; 102, detection electrode; 103, fixed lower chassis; 104, edge shielding; 105, external shielding; 106, radial thread; 200, switch gating array; 300, data acquisition module; 400, data processing module; 500, ice crystal recognition module; 600, frozen soil specimen; 601, parallel lines. DETAILED DESCRIPTION

[0036] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms and other features not clearly described in this technical solution are all considered to be common technical features disclosed in the prior art.

[0037] Example 1

[0038] like Figure 1 As shown, this embodiment provides a frozen soil ice crystal migration test device using capacitance measurement, comprising a scanning annular capacitance sensor 100, a data acquisition module 300, a data processing module 400 and an ice crystal identification module 500. The scanning annular capacitance sensor 100 is vertically movable and sleeved on the test piece, and is used to detect ice crystals inside the frozen soil by moving scanning. The vertical movement is shown in FIG. Figure 4 . The sensor is equipped with multiple detection electrodes 102. The data acquisition module 300 connects the electrodes through the switch selection array 200, and is responsible for obtaining the capacitance data generated when the sensor moves along the test piece. The data includes the capacitance value between each cross section. The switch selection array 200 is used to select the excitation electrode and the receiving electrode. The data processing module 400 draws a fluctuation graph of the total capacitance value based on the capacitance data, showing the changes along the vertical direction. The ice crystal recognition module 500 determines the position of the ice crystal surface by analyzing the fluctuation graph.

[0039] like Figure 2 As shown, the scanning annular capacitive sensor 100 includes a hollow cylindrical base 101, a fixed lower chassis 103, an edge shield 104 and an external shield 105. The hollow cylindrical base 101 is mounted on the fixed lower chassis 103. A plurality of detection electrodes 102 are arranged on the outer surface of the base 101. The edge shield 104 is annular and covers both ends of each detection electrode 102 to reduce the electric field distortion at the edge of the sensor and ensure uniform electric field distribution. The external shield 105 is also annular and covers the outside of each detection electrode 102, and extends in the length direction to cover the base 101, thereby reducing external electromagnetic interference. A radial threaded hole 106 is provided on the fixed lower chassis 103, which is used to fix the scanning annular capacitive sensor 100 at a specific position of the test piece 600.

[0040] The hollow cylindrical base 101 and the fixed lower chassis 103 are both made of insulating materials, such as organic glass, while the detection electrodes, the edge shielding and the outer shielding are made of conductive metal, such as copper sheets.

[0041] In this embodiment, the test target is a frozen soil specimen 600 with a diameter of 100 mm and a height of 170 mm. The dimensions of the hollow cylindrical base 101 and the fixed lower chassis 103 match the specimen. Specifically, the base 101 is a plexiglass with a height of 30 mm, a wall thickness of 2 mm, and an inner diameter of 51 mm, which fits the outer wall of the frozen soil specimen and can move vertically.

[0042] The fixed lower chassis 103 has an inner diameter of 51 mm, an outer diameter of 70 mm, and a thickness of 15 mm, and is also made of organic glass. Its upper end is fixed to the lower end of the base 101 with an organic insulating adhesive (such as AB glue). The fixed chassis 103 is provided with four radial threaded holes 106, which are used to fix the relative position of the base 101 by bolts when the base 101 moves vertically along the specimen. The bolts can be hexagonal bolts.

[0043] In this embodiment, four detection electrodes 102 are provided in total with the same size. Each electrode plate is a copper sheet with a length of 20 mm, a width of 20 mm and a thickness of 0.5 mm, and is evenly installed in the middle of the outer surface of the hollow cylindrical base 101 .

[0044] In this embodiment, the edge shield 104 is annular, with an inner diameter consistent with the outer diameter of the hollow cylindrical base, a length of 2 mm, covering the upper and lower parts of the electrode plate 102, maintaining insulation and a spacing of 2 mm. The outer shield 105 is also annular, with a length of 30 mm and an inner diameter of 65 mm, covering the outside of the hollow cylindrical base 101 and maintaining insulation from the electrode.

[0045] In this embodiment, each electrode 102 is connected by welding through a signal transmission line, and the edge shield 104 and the outer shield 105 are connected to an external ground line. In use, the electrode 102 is connected to the switch gating array 200 through a transmission line, and then the array is selected as an excitation or receiving electrode to complete the acquisition of capacitance data.

[0046] In this embodiment, the method for realizing ice crystal identification using the above-mentioned frozen soil ice crystal migration testing device is as follows: Figure 3 As shown, the following steps are included:

[0047] In step S1, see Figure 4 The frozen soil specimen 600 is vertically divided into parallel lines 601 with equal intervals (such as 20 mm). The annular capacitive sensor 100 is mounted on the specimen 600 and moved vertically so that the center line of the detection electrode 102 is aligned with the parallel lines 601, and the capacitance values ​​of multiple cross sections are detected by using the electrode.

[0048] In step S2, the total capacitance value of each cross section is calculated according to the capacitance value, and a fluctuation diagram along the vertical direction is drawn.

[0049] In step S3, the position where the capacitance sum value fluctuates most significantly is identified as the frozen soil ice crystal surface. Figure 5 The figure shows the ice crystal surface recognition result of this embodiment.

[0050] If the above method is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0051] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A frozen soil ice crystal migration test device based on capacitance measurement, characterized in that: include: A scanning annular capacitive sensor (100) can be sleeved on a test object and can move vertically relative to the test object, wherein a plurality of detection electrodes (102) are provided on the scanning annular capacitive sensor (100), and the test object is a frozen soil sample; A data acquisition module (300) is connected to the detection electrode (102) via a switch gating array (200), the data acquisition module (300) being used to acquire capacitance data of the scanning annular capacitance sensor (100) during vertical movement, the capacitance data comprising capacitance values ​​at a plurality of cross sections; The data processing and identification module (400) is used to generate a capacitance total value fluctuation diagram of different cross sections of the test piece according to the capacitance data, and determine the ice crystal surface position, that is, the total capacitance peak value, according to the capacitance total value fluctuation diagram.

2. A frozen soil ice crystal migration test device based on capacitance measurement according to claim 1, characterized in that: The scanning annular capacitive sensor (100) comprises a hollow cylindrical base (101), a fixed lower chassis (103), an edge shield (104), and an external shield (105).

3. A frozen soil ice crystal migration test device based on capacitance measurement according to claim 2, characterized in that: The hollow cylindrical base (101) is mounted on the fixed lower chassis (103); A plurality of detection electrodes (102) are arranged on the outer surface of the base (101).

4. The frozen soil ice crystal migration test device based on capacitance measurement according to claim 2, characterized in that: The edge shield (104) is ring-shaped and covers both ends of each detection electrode (102) to reduce electric field distortion at the edge of the sensor and ensure uniform electric field distribution; The external shield (105) is ring-shaped, and the external shield (105) is wrapped around the outside of each detection electrode (102). The external shield (105) extends in the length direction to cover the base (101), thereby reducing external electromagnetic interference.

5. The frozen soil ice crystal migration test device based on capacitance measurement according to claim 2, characterized in that: The fixed lower chassis (103) is provided with a radial threaded hole (106), and the radial threaded hole (106) is used to fix the scanning annular capacitance sensor (100) on the object to be tested (600).

6. The frozen soil ice crystal migration test device based on capacitance measurement according to claim 2, characterized in that: The hollow cylindrical base (101) and the fixed lower chassis (103) are both made of insulating materials.

7. The frozen soil ice crystal migration test device based on capacitance measurement according to claim 2, characterized in that: Insulating materials are provided between the edge shield (104), the external shield (105) and the detection electrode (102); The detection electrode (102), the edge shield (104) and the external shield (105) are all made of conductive metal material.

8. The frozen soil ice crystal migration test device based on capacitance measurement according to claim 2, characterized in that: The detection electrode (102) is evenly fixed to the middle of the outer surface of the hollow cylindrical base (101).

9. A frozen soil ice crystal migration test method using the test device as claimed in any one of claims 1 to 8, comprising the following steps: Obtaining capacitance values ​​at each cross section of the test piece from the detection electrode (102); Calculating the total capacitance value of each cross section based on the acquired capacitance value, and generating a fluctuation diagram of the total value along the vertical direction; The maximum position of the total capacitance, that is, the position of the ice crystal surface inside the frozen soil, is determined based on the fluctuation diagram.

10. A storage medium containing computer executable instructions, characterized in that: The storage medium of the computer executable instructions is used to execute the soil ice crystal migration test method as described in claim 9 when executed by a computer processor.

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