Device and method for measuring porosity of roadbed block stone layer

Abstract

The invention relates to the technical field of roadbed engineering, in particular to a roadbed block stone layer porosity measuring device and method.The measuring device obtains the section resistivity through the section resistivity imaging technology, and therefore the block stone layer porosity is calculated; the camera device is used for verifying the accuracy degree of the dimension stone layer pore distribution result tested by the electricity testing device; the energy supply device can supply energy to the electricity measuring device and the camera device, so that the electricity measuring device and the camera device normally operate; in the electricity measuring device, the voltage transformation module is used for boosting the voltage of the electrode module, and the data precision is improved through multiple times of boosting acquisition, so that the obtained porosity data of the roadbed block stone layer is more accurate; the determination method comprises the following steps: performing multiple times of collection at a set section through a plurality of electrode modules to obtain a relative ratio of block stones to air; integrating the two-dimensional data result of the section of the roadbed to finally obtain the overall porosity of the three-dimensional roadbed; the porosity of the block stone layer of the block stone roadbed can be rapidly and accurately measured.

Description

Technical Field

[0001] The present invention relates to the technical field of subgrade engineering, and particularly relates to a device and a method for measuring the porosity of a block stone layer of a subgrade. Background Art

[0002] Frozen soil is sensitive to climate and environmental changes. To reduce the subgrade thaw settlement diseases caused by global warming and engineering disturbances, the "active cooling subgrade" mainly composed of block stone subgrade stores cold energy into the underlying permafrost by regulating the forced convection effect in the cold season and the weak natural convection effect in the warm season, and the block stone subgrade is widely used in frozen soil subgrade engineering; problems such as block stone weathering and clay accumulation will occur in the block stone subgrade, resulting in block stone pore blockage and affecting its cooling effect. Therefore, it is necessary to regularly detect the porosity of the block stone subgrade.

[0003] The measurement and evaluation of the porosity of the block stone layer are the prerequisites for improving the service performance of the block stone subgrade. However, at present, the field of methods for measuring the porosity of the block stone subgrade is still blank; currently, the methods for measuring the porosity of rock and soil masses include the mass / gas method, nuclear magnetic resonance method, CT test method, etc. The above test methods have strict requirements for sample size and experimental conditions and are difficult to apply to on-site detection; in Chinese Patent CN118130336A, a method for detecting the porosity of asphalt pavement by capacitance calibration is proposed, but the method it adopts cannot be applied to the porosity detection of large-scale and large-scale block stone subgrades. Summary of the Invention

[0004] The purpose of the present invention is to solve the deficiency that it is difficult to directly detect the porosity of the block stone layer on-site in the existing methods for detecting the porosity of the block stone subgrade, and to provide a device and a method for measuring the porosity of a block stone layer of a subgrade.

[0005] In a first aspect, the present invention provides a device for measuring the porosity of a block stone layer of a subgrade, comprising: An electric measurement device, the electric measurement device includes an electrode module, a voltage transformation module, an electric measurement module, and an electrode conversion module. The electric measurement module is connected to the electrode conversion module, the electric measurement module is connected to the electrode module, and the voltage transformation module is connected to the electrode conversion module; A camera device, the camera device includes an image acquisition module and a storage module, and the image acquisition module is electrically connected to the storage module; An energy supply device, the storage module is electrically connected to the energy supply device, and the voltage transformation module is electrically connected to the energy supply device.

[0006] A device for measuring the porosity of a roadbed stone layer of the present invention lowers the electrode module of the electric measurement device to the stone layer, obtains the resistance data of the measurement point by discharging through multiple electrode modules, and uses the cross-sectional resistivity imaging technology (ERT) to obtain the resistivity of the cross-section, thereby calculating the porosity of the stone layer; the imaging device is used to verify the accuracy of the porosity distribution result of the stone layer tested by the electric measurement device; the power supply device can supply power to the electric measurement device and the imaging device to make the electric measurement device and the imaging device operate normally; in the electric measurement device, the voltage of the electrode module is increased by the voltage transformation module, and the data accuracy is improved by collecting the voltage multiple times, so that the porosity data of the roadbed stone layer obtained is more accurate; it can quickly and accurately detect the porosity of the in-service stone roadbed or the newly built stone roadbed.

[0007] Preferably, the electrode module includes a central electrode, an extended wire harness and a wire. The wire and the extended wire harness are respectively located at both ends of the central electrode. The extended wire harness is connected to the central electrode, the wire is connected to the central electrode, and the wire is electrically connected to the electric measurement module.

[0008] The central electrode is a cylindrical electrode. An extended wire harness is provided at one end of the central electrode. By attaching the extended wire harness to the stone, the measurement accuracy is ensured. The central electrode is connected to the electric measurement module through a wire, which is convenient for the operator to install and use the central electrode.

[0009] Preferably, the extended wire harness includes a snap ring and a plurality of electrode wires. The plurality of electrode wires are arranged in a ring at the end of the central electrode. Adjacent electrode wires are arranged at intervals. The end of the electrode wire is hinged to the central electrode. The electrode wire is connected to the snap ring, and the diameter of the snap ring can be adjusted.

[0010] When setting the central electrode, by adjusting the snap ring, the electrode wire can be rotated to a suitable position so that the stone is covered by the electrode wire, thereby ensuring the measurement accuracy of the electrode.

[0011] Preferably, the power supply device includes a solar panel and a storage battery. The solar panel is electrically connected to the storage battery. The electric measurement module is electrically connected to the storage battery. The storage module is electrically connected to the storage battery.

[0012] Using the storage battery and the solar panel, the measuring device can be used without a wired power supply, which is more suitable for the roadbed measurement in the outdoor field, and the outdoor endurance of the measuring device is enhanced by the solar panel.

[0013] Preferably, the image acquisition module includes an auto-focus imaging device.

[0014] The auto-focus imaging device can accurately capture the gap image in the stone layer, improving the accuracy of verifying the porosity distribution result of the stone layer tested by the electric measurement device.

[0015] In a second aspect, the present invention provides a method for measuring the porosity of a subgrade rubble layer. Using the above-mentioned device for measuring the porosity of a subgrade rubble layer, the method includes the following steps: S1: Determine the positions of the measuring lines and measuring points: Set a number of vertical rectangular observation surfaces located within the rubble layer. The area of the rectangular observation surface is A, and a measuring line having the same length as the rectangular observation surface is provided within the rectangular observation surface; Measuring lines L1, L2, L3... L N are respectively set in different rectangular observation surfaces. The measuring lines are arranged along the direction of the subgrade, and the spacing between adjacent measuring lines in the width direction of the subgrade is ; A number of measuring points are arranged at intervals on the measuring lines; S2: Select a measuring line: Select measuring line L1 as the measuring line; S3: Arrange the acquisition mechanism: Connect the electrode module and the image acquisition module to form an acquisition mechanism, and respectively set the acquisition mechanism at the measuring points on the selected measuring line; S4: Measure the resistance data of the measuring points: Adjust the voltage of the transformer to obtain the resistance data of the measuring points when the pore information reflected by the resistance data of the measuring points is consistent with the pore information obtained by the image acquisition module; S5: Measure the resistance data of measuring lines L2, L3... L N : Repeat steps S3 - S4 to sequentially obtain the resistance data of the measuring points on measuring lines L2, L3... L N , and obtain multiple groups of data, which are the corresponding data result points, and are respectively recorded as:

[0016]

[0017]

[0018] where X is the horizontal distance, Y is the depth, and R is the resistance value, to obtain multiple groups of resistance data containing two-dimensional coordinates; S6: Obtain the pore area of the observation surface: Based on the resistance data of the measuring points of the selected measuring line, obtain the cross-sectional resistance cloud map of the rectangular observation surface where the measuring line is located. Divide the cross-sectional resistance cloud map into several squares. If the resistance of a square is greater than 1000Ω, determine that the square is air; The pore area in the cross-section is , is the area of the pore unit, and R is the resistance data of the selected measuring point; S7: Calculate the total pore volume: Calculate the total pore volume through the formula ; S8: Calculate the porosity: Given the total volume of the tested rubble layer, then the total porosity of the subgrade rubble layer , where n is the number of electrodes, A is the test cross-sectional area, and the calculation formula is: , L is the length of the test section, and D is the height of the test section, both of which are related to the number of electrodes. , a is the electrode spacing, the electrode spacing is a constant, D=k*a, k is a constant related to the electrode arrangement.

[0019] The present invention provides a method for measuring the porosity of a rock layer of a roadbed. Multiple electrodes collect data multiple times at a set section to obtain the relative proportion of rock to air. The three-dimensional data results of the roadbed section are integrated to finally obtain the overall porosity of the three-dimensional roadbed. The porosity of the rock layer of the rock roadbed can be measured quickly and accurately. A technical paradigm is provided for the field of porosity detection of rock roadbeds, with high detection efficiency, which is beneficial to the demand for a short construction window period in frozen soil areas. The determination method can protect the roadbed structure, ensure the accuracy of the determination results, and avoid distortion of the detection data. It is free from laboratory limitations and can achieve rapid detection of the porosity of the rock layer at the construction site.

[0020] Preferably, in S4, the voltage of the transformer module is adjusted to 48V, 100V and 144V in sequence, and the resistance data of the measuring point when the pore information reflected by the resistance data is consistent with the pore information acquired by the image acquisition module is selected.

[0021] By setting multiple voltage values ​​and using multiple electrode modules to collect data multiple times at the set observation surface, accurate data on the relative proportion of stone and air can be obtained; by comparing the pore information reflected by the resistance data with the pore information obtained by the image acquisition module, the accuracy of the resistance data can be determined.

[0022] Preferably, in S7, using the formula , reduce ∆d in sequence to obtain V1, V2, V3...V n , until (V n -V n-1 ) / V n-1 When <1%, V n As the total pore volume V.

[0023] By changing the value of ∆d, the measured total pore volume is made consistent with the actual total pore volume.

[0024] Preferably, in S1, when inspecting an existing roadbed, the electrode module is moved to a specified depth; when inspecting a newly built roadbed, the electrode module is pre-buried at the interface between the block stone layer and the upper fill layer.

[0025] The determination method can be used for testing existing roadbeds and newly built roadbeds using different layout methods.

[0026] Preferably, in S1, the electrode module is in close contact with the stone block.

[0027] By adjusting the close contact between the electrode module and the crushed stones, the measurement accuracy of the resistance data at the measurement points is ensured, and the accuracy of the total porosity of the crushed stone layer subgrade is guaranteed.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention provides a device for measuring the porosity of a subgrade crushed stone layer. By lowering the electrode module of the electric measurement device to the crushed stone layer, resistance data at the measurement points are obtained through the discharge of multiple electrode modules, and the resistivity of the cross-section is obtained by using the electrical resistivity tomography (ERT) technique, thereby calculating the porosity of the crushed stone layer; the imaging device is used to verify the accuracy of the porosity distribution result of the crushed stone layer tested by the electric measurement device; the power supply device can supply power to the electric measurement device and the imaging device to enable the normal operation of the electric measurement device and the imaging device; in the electric measurement device, the voltage of the electrode module is increased by using a voltage transformation module, and the data accuracy is improved by multiple voltage boosts, making the obtained porosity data of the subgrade crushed stone layer more accurate; the porosity of the in-service or newly built crushed stone subgrade can be detected quickly and accurately. 2. The method for measuring the porosity of a subgrade crushed stone layer of the present invention obtains the relative proportion of crushed stones and air through multiple collections at a set cross-section by multiple electrode modules; by integrating the two-dimensional data results of the subgrade cross-section, the overall three-dimensional porosity of the subgrade is finally obtained; the porosity of the crushed stone layer of the crushed stone subgrade can be measured quickly and accurately; it provides a technical paradigm for the field of porosity detection of crushed stone subgrades, has high detection efficiency, and is conducive to the requirements of the short construction window period in the frozen soil area; the measurement method can protect the subgrade structure, ensure the accuracy of the measurement results, and avoid the distortion of detection data; it is not restricted by the laboratory and can realize the rapid detection of the porosity of the crushed stone layer at the construction site. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of a device for measuring the porosity of a subgrade crushed stone layer in Embodiment 1; Figure 2 It is a schematic structural diagram of the electrode module of a device for measuring the porosity of a subgrade crushed stone layer in Embodiment 1; Figure 3 It is a schematic diagram of the unfolded state of the electrode wire of a device for measuring the porosity of a subgrade crushed stone layer in Embodiment 1; Figure 4 It is a schematic flow diagram of a method for measuring the porosity of a subgrade crushed stone layer in Embodiment 2; Figure 5 It is a schematic diagram of the subgrade cross-section of a method for measuring the porosity of a subgrade crushed stone layer in Embodiment 2; Figure 6 It is a schematic diagram of the subgrade observation surface of a method for measuring the porosity of a subgrade crushed stone layer in Embodiment 2; Figure 7Schematic layout diagram of the roadbed survey line for the method of measuring the porosity of the roadbed stone layer in Example 2; Figure 8 Schematic layout diagram of the in-service roadbed survey line for the method of measuring the porosity of the roadbed stone layer in Example 2; Figure 9 Schematic layout diagram of the measuring points of the in-service roadbed survey line for the method of measuring the porosity of the roadbed stone layer in Example 2; Figure 10 Schematic layout diagram of the observation surface of the newly-built roadbed for the method of measuring the porosity of the roadbed stone layer in Example 2; Figure 11 Schematic layout diagram of the measuring points of the newly-built roadbed for the method of measuring the porosity of the roadbed stone layer in Example 2; Figure 12 Schematic diagram of the implementation process for the method of measuring the porosity of the roadbed stone layer in Example 2; Figure 13 Schematic diagram of the cross-sectional resistance cloud map for the method of measuring the porosity of the roadbed stone layer in Example 2.

[0030] Markings in the figure: 1 - Electrode module, 2 - Image acquisition module, 3 - Electric measurement module, 4 - Electrode conversion module, 5 - Voltage transformation module, 6 - Energy supply device, 7 - Storage module, 8 - Block stone roadbed, 9 - Stone layer, 10 - Survey line, 11 - Measuring point, 12 - Observation surface of in-service roadbed, 13 - Test result point, 14 - Observation surface of newly-built roadbed, 16 - Extended wire bundle, 161 - Electrode wire, 162 - Snap ring, 17 - Central electrode, 18 - Conducting wire. Detailed implementation manners

[0031] The present invention will be further described in detail below with reference to specific embodiments. However, it should not be understood that the scope of the above-mentioned subject matter of the present invention is limited to the following embodiments. All technologies implemented based on the content of the present invention belong to the scope of the present invention.

[0032] In the description of the specific embodiments of the present invention, without special instructions, the expression terms indicating the orientation or positional relationship such as "upper", "lower", "left", "right", "center", "inner", "outer", etc. are all based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the invention product / device / equipment is commonly used and placed. These terms of orientation or positional relationship are only for the convenience of describing the solution of the present invention or simplifying the description in the specific embodiments, so as to facilitate technicians to quickly understand the solution, rather than indicating or implying that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, it should not be construed as a limitation to the present invention.

[0033] In addition, when terms such as "horizontal", "vertical", "hanging", "parallel" appear, it does not mean that the corresponding device / component / element is required to be absolutely horizontal or vertical or hanging or parallel, but it can be slightly inclined or deviated. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and it does not mean that the structure must be completely horizontal, but it can be slightly inclined. Or, it can be simply understood that the corresponding device / component / element is arranged in directions such as "horizontal", "vertical", "hanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the solution of the present invention.

[0034] In addition, when expressions such as "first", "second", "third", etc. appear in the terms, they are only used to distinguish the description of the same or similar components, and should not be understood as emphasizing or implying the relative importance of specific components.

[0035] In addition, in the description of the embodiments of the present invention, "several", "multiple", "a number of" represent at least 2. It can be any situation such as 2, 3, 4, 5, 6, 7, 8, 9, etc., and even can be a situation exceeding 9.

[0036] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, when terms such as "arranged", "installed", "connected", "linked", "provided with", "laid", "disposed" appear, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be connection means commonly used in the art such as welding, riveting, bolting, threaded connection, etc. This connection can be a mechanical connection, an electrical connection or a communication connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components.

[0037] Embodiment 1 As Figures 1 - 3 shown, a device for measuring the porosity of a subgrade crushed stone layer, characterized by comprising: An electric measuring device, the electric measuring device includes an electrode module 1, a voltage transformation module 5, an electric measuring module 3 and an electrode conversion module 4. The electric measuring module 3 is connected to the electrode conversion module 4, the electric measuring module 3 is connected to the electrode module 1, and the voltage transformation module 5 is connected to the electrode conversion module 4; A camera device, the camera device includes an image acquisition module 2 and a storage module 7, and the image acquisition module 2 is electrically connected to the storage module 7; The energy supply device 6, the storage module 7 is electrically connected to the energy supply device 6, and the voltage transformation module 5 is electrically connected to the energy supply device 6.

[0038] By lowering the electrode module 1 of the electric measurement device to the cobblestone layer 9, discharging through multiple electrode modules 1 to obtain the resistance data of the measurement point, and using the cross-sectional resistivity imaging technology ERT to obtain the resistivity of the cross-section, thereby calculating the porosity of the cobblestone layer; the camera device is used to verify the accuracy of the cobblestone layer porosity distribution result tested by the electric measurement device; the energy supply device 6 can supply energy to the electric measurement device and the camera device to make the electric measurement device and the camera device operate normally; in the electric measurement device, the voltage transformation module 5 is used to increase the voltage of the electrode module 1, and the data accuracy is improved by multiple voltage boosts, so that the obtained porosity data of the subgrade cobblestone layer 9 is more accurate; it can quickly and accurately detect the porosity of the in-service cobblestone subgrade or the newly built cobblestone subgrade.

[0039] The electric measurement device is used to measure and collect the resistance on the observation surface of the subgrade cobblestone layer.

[0040] In an optional implementation manner, the electrode module 1 is composed of a central electrode 17, an extended wire harness 16 and a wire 18. The central electrode 17 is a columnar structure, which makes it easier to set the central electrode 17 at the specified position of the cobblestone layer 9. The wire 18 and the extended wire harness 16 are respectively located at both ends of the central electrode 17. The extended wire harness 16 is in contact with the cobblestones, so as to ensure the accuracy of the data collected by the central electrode 17. The extended wire harness 16 is connected to the central electrode 17, and the wire 18 is connected to the central electrode 17. The wire uses a soft cable, which is convenient for moving the position of the central electrode 17. The wire 18 is electrically connected to the electric measurement module 3. Through the electric measurement module 3, the electric quantity data collected by the central electrode 17 can be converted into the resistance data of the measurement point 11.

[0041] In an alternative embodiment, the extended wire harness 16 is composed of a snap ring 162 and a plurality of electrode wires 161. The plurality of electrode wires 161 are arranged in a ring at the end of the central electrode 17 with the center of the end face of the central electrode 17 as the center. The electrode wires 161 are connected to the edge of the end face of the central electrode 17. There is a gap between adjacent electrode wires 161. The ends of the electrode wires 161 are hinged to the central electrode 17 so that the electrode wires 161 can rotate in the radial direction of the central electrode 17. The electrode wires 161 are connected to the snap ring 162, and the diameter of the snap ring 162 can be adjusted. By adjusting the diameter of the snap ring 162, the plurality of electrode wires 161 can be wrapped around block stones of different sizes, thereby improving the accuracy of the electrical measurement results. The snap ring is composed of a first arc-shaped flap and a second arc-shaped flap. The first arc-shaped flap and the second arc-shaped flap are connected by an adjustment buckle. By adjusting the connection position of the adjustment buckle with the first arc-shaped flap and the second arc-shaped flap, the diameter adjustment of the snap ring is realized. To ensure that the adjusted snap ring is circular, both the first arc-shaped flap and the second arc-shaped flap are rubber material structural members.

[0042] In an alternative embodiment, the energy supply device 6 is composed of a solar panel and a storage battery. The solar panel is electrically connected to the storage battery, and the storage battery is powered by the solar panel, enabling it to be used without a fixed power source, making the measurement device suitable for outdoor environments. The electrical measurement module 3 is electrically connected to the storage battery, and the storage module 7 is electrically connected to the storage battery. The storage battery stably supplies power to the electrical measurement module 3 and the storage module 7.

[0043] In an alternative embodiment, the image acquisition module 2 includes an auto-focus camera device to obtain more accurate pore image information.

[0044] Specifically, for a device for measuring the porosity of a subgrade block stone layer, the electrical measurement device composed of the electrode module 1, the voltage transformation module 5, the electrical measurement module 3, and the electrode conversion module 4 forms an electrical signal acquisition system for collecting the electrical signal distribution of the cross-section of the block stone layer 9, thereby obtaining the pore information of the block stone layer 9. The electrode module 1 solves the problem of difficult installation and fixation due to large gaps between block stones. The electrode module 1 is composed of a plurality of electrode wires 161, a snap ring 162, a central electrode 17, and a wire 18. Among them, the electrical measurement module 3 and the electrode conversion module 4 form the acquisition system. The electrode module 1 is connected to the electrical measurement module 3, and the electrode conversion module 4 is connected to the electrical measurement module 3. When in use, the central electrode 17 of the electrode module 1 is connected to the image acquisition module 2 by a lock and placed together in the block stone layer 9. The electrode conversion module 4 is an electrode converter, and the electrical measurement module 3 is a digital electrical measuring instrument.

[0045] The voltage transformation module 5: used to provide low-voltage - high-voltage signals, raise the voltage at the selected subgrade cross-section, and improve data accuracy by multiple voltage boosts. The voltage transformation module 5 includes a transformer.

[0046] Power supply device 6: It is composed of a solar panel and a storage battery. The solar panel can convert solar energy into electrical energy to charge the storage battery. It is suitable for long-term monitoring and provides electrical energy for the imaging device and the electrical measurement device.

[0047] Imaging device: It is used to verify the accuracy of the pore distribution results of the block stone layer tested by the electrical measurement device. The imaging device includes an image acquisition module 2 and a storage module 7; the image acquisition module 2 is connected to the storage module 7. The image acquisition module 2 is an automatically zoomable imaging device, and the storage module 7 is a computer mainframe.

[0048] Embodiment 2 As Figures 4 - 12 shown, a method for measuring the porosity of a subgrade block stone layer uses the device for measuring the porosity of a subgrade block stone layer in Embodiment 1, and includes the following steps: S1: Determine the positions of the measurement line 10 and the measurement points 11: Set a number of vertical rectangular observation surfaces. The rectangular observation surfaces are located in the block stone layer 9. The area of the rectangular observation surface is A. A measurement line 10 with the same length as the rectangular observation surface is provided in the rectangular observation surface; in different rectangular observation surfaces, measurement lines 10L1, L2, L3... L N , the measurement line 10 is arranged along the direction of the subgrade, and the distance between adjacent measurement lines 10 in the width direction of the subgrade is ; a number of measurement points 11 are arranged at intervals on the measurement line 10; S2: Select the measurement line 10: Select the measurement line 10L1 as the measurement line; S3: Arrange the acquisition mechanism: Connect the electrode module 1 and the image acquisition module 2 to form an acquisition mechanism, and respectively set the acquisition mechanism on the measurement points 11 of the selected measurement line 10; S4: Measure the resistance data of the measurement points 11: Adjust the voltage of the transformer to obtain the resistance data of the measurement points 11 when the pore information reflected by the resistance data of the measurement points 11 is consistent with the pore information obtained by the image acquisition module 2; S5: Conduct the measurement of the resistance data of the measurement lines 10L2, L3... L N : Repeat steps S3 - S4 to sequentially obtain the resistance data of the measurement points 11 on the measurement lines 10L2, L3... L N to obtain multiple groups of data, which are the corresponding data result points, and are respectively recorded as:

[0049]

[0050]

[0051] X is the horizontal distance, Y is the depth, and R is the resistance value, that is, multiple groups of resistance data containing two-dimensional coordinates are obtained; take the average value of these resistance data; S6: Obtain the pore area of the observation face: Based on the resistance data of the measuring point 11 on the selected measuring line 10, obtain the cross-sectional resistance cloud map of the rectangular observation face where the measuring line 10 is located. Divide the cross-sectional resistance cloud map into several squares. If the resistance of a square is greater than 1000 Ω, determine that the square is air; the pore area in the cross-section is , is the area of the pore unit, R is the resistance data of the selected measuring point 11, is the total pore area, n = 1, 2... n, is the area of the pore unit, R is the resistance data of the selected measuring point 11; S7: Calculate the volume of the total pores: Calculate the volume of the total pores through the formula ; S8: Porosity calculation: Given the total volume of the test block stone layer, then the total porosity of the block stone layer subgrade , where n is the number of electrodes, A is the area of the test cross-section, and its calculation formula is , L is the length of the test cross-section, D is the height of the test cross-section, and both are related to the number of electrodes. , a is the electrode spacing, the electrode spacing is a constant, D = k * a, k is a constant related to the electrode arrangement method, generally 2 or 3; the value of k is mainly affected by the signal strength of the block stone medium. Weathering and dampness of the block stone will both reduce signal transmission. When the weathering degree is high and the humidity is high on the surface of the block stone layer, k takes 2; when the weathering degree is low, the service life is short, and the humidity is low and relatively dry on the surface of the block stone layer, k takes 3; further, for the block stone layer subgrade with no thermokarst lake pond around or the groundwater level more than 0.5 m below the ground surface and a service period of 0 - 3 years, k = 3. When there is a thermokarst lake pond around or the groundwater level is close to the ground surface less than 0.5 m below, and the service period of the block stone subgrade is 3 - 10 years, k = 2.

[0052] Multiple electrodes are used to collect data multiple times at the set cross-section to obtain the relative proportion of block stone and air; by integrating the two-dimensional data results of the subgrade cross-section, the overall porosity of the three-dimensional subgrade is finally obtained; realizing the rapid and accurate determination of the porosity of the block stone layer of the block stone subgrade; providing a technical paradigm for the field of block stone subgrade porosity detection, with high detection efficiency and being conducive to the needs of the short construction window period in the permafrost area; the said determination method can protect the subgrade structure, ensure the accuracy of the determination result, and avoid the distortion of detection data; breaking away from the laboratory restrictions, it can realize the rapid detection of the porosity of the block stone layer at the construction site.

[0053] In one or several embodiments, in S4, the voltage of the variable voltage module 5 is adjusted to 48 V, 100 V, and 144 V in sequence, and the resistance data of the measuring point 11 is selected when the pore information reflected by the resistance data is consistent with the pore information obtained by the image acquisition module 2.

[0054] In one or several embodiments, in S7, using the formula , ∆d is sequentially decreased to obtain V1, V2, V3... V n , until (V n - V n-1 ) / V n-1 < 1%, and make V n as the total pore volume V.

[0055] In one or several embodiments, in S1, when detecting the existing subgrade, move the electrode module 1 to the specified depth; when detecting the new subgrade, pre-embed the electrode module 1 at the interface between the rubble layer 9 and the upper soil filling layer.

[0056] In one or several embodiments, in S1, the electrode module 1 is in close contact with the rubble.

[0057] Specifically, a method for measuring the porosity of the subgrade rubble layer is as follows: Step 1: Assemble the electric measurement device, the imaging device and the power supply device 6. Preheat the digital electric meter, the electrode converter and the transformer for 10 minutes in advance, and adjust the imaging device to make it clearly display; Step 2: Install the electrode module 1 and apply a conductive material on the electrode wire 161; divide the observation surface of the rubble subgrade 8. The number of observation surfaces is controlled by the width of the subgrade, and the observation surfaces are located in the rubble layer 9; select the line parallel to the subgrade trend in the observation surface as the measurement line 10, and set measurement points 11 on the measurement line. The number of measurement points 11 is controlled by the thickness of the rubble layer 9; place the electrode module 1 in the rubble layer 9 and adjust the snap ring 162 to ensure that the electrode wire 161 is in close contact with the rubble; determine the measurement lines 10L1, L2, L3... L N ; Connect the electrode module 1 and the imaging module together through a buckle to form a collection mechanism; the spacing between adjacent measurement lines 10 in the width direction of the subgrade is , and the area of the rectangular observation surface is A; Step 3: Conduct the first collection. Place several collection mechanisms at the block L1, set the test voltage of the electrode module 1 to 48v, and record the resistance data of the measurement points 11; Step 4: Repeat the collection. At an interval of 2 minutes, increase the test voltage, and verify the image through the imaging device at the measurement point 11. When the pore information reflected by the test result is consistent with the pore information reflected by the imaging device, record the resistance data of the measurement point 11 as , and complete the result of the first measurement line 10; the test voltage can be increased to 100V or 144V; Step 5: Change the observation line 10, adjust the size of the snap ring 162 to make the electrode movable, and place the electrode at the rubble layer 9L2, L3... L N places, and the spacing between two adjacent measurement lines 10 is , , Repeat steps three and four to complete the testing of the 2nd, 3rd... nth survey line 10; Step six: Based on the resistance data of the measuring points 11 on the selected survey line 10, obtain the cross-sectional resistance contour map of the rectangular observation plane where the survey line 10 is located. Divide the cross-sectional resistance contour map into several squares. If the resistance of a square is greater than 1000 Ω, determine that the square is air; the pore area in the cross-section is , , where $S_i$ is the area of the pore unit and $R$ is the resistance data of the selected measuring point 11; Step seven: Calculate the total pore volume: Calculate the total pore volume through the formula ; Step eight: Gradually decrease , recalculate the total pore volume $V_2$,... $V_n$ until $(V_n - V_{n - 1}) / V_{n - 1} \lt 1\%$; Step nine: Porosity calculation: Given the total volume of the test rubble layer, then the total porosity of the rubble layer subgrade.

[0058] The above method for measuring the porosity of the rubble layer of the frozen soil subgrade can be applied to the porosity detection of the rubble layer of in-service roads and the porosity detection of the rubble layer of newly built roads. For newly built roads, the electrode module 1 adopts a fixed wiring method, and for in-service roads, the electrode module 1 adopts a mobile wiring method.

[0059] The mobile wiring method is as Figure 8 shown. Arrange the new electrode module 1 in the rubble medium. Before testing, the electrode needs to be moved to a certain depth to achieve multi-section monitoring of the pores in the rubble subgrade; it is applicable to the detection of in-service rubble subgrades, such as Figure 9 shown, and several test result points 13 can be obtained on the observation plane 12 of the in-service subgrade.

[0060] The fixed wiring method is as Figures 10 - 11 shown. Embed the electrode module 1 at the interface between the rubble layer 9 and the upper soil filling layer to form the observation plane 14 of the newly built subgrade; during the testing process, the electrode module 1 does not need to be moved to achieve real-time dynamic detection of the porosity of the rubble subgrade; the service performance of the porosity of the rubble layer can be detected according to a one-year service cycle; it is applicable to the detection of newly built rubble subgrades.

[0061] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A device for measuring the porosity of a roadbed rock layer, characterized in that: include: An electric power measuring device, the electric power measuring device comprising an electrode module (1), a voltage transformation module (5), an electric power measuring module (3) and an electrode conversion module (4), the electric power measuring module (3) being connected to the electrode conversion module (4), the electric power measuring module (3) being connected to the electrode module (1), and the voltage transformation module (5) being connected to the electrode conversion module (4); A camera device, the camera device comprising an image acquisition module (2) and a storage module (7), the image acquisition module (2) being electrically connected to the storage module (7); An energy supply device (6), the storage module (7) being electrically connected to the energy supply device (6), and the voltage transformation module (5) being electrically connected to the energy supply device (6).

2. The device for measuring the porosity of a roadbed rock layer according to claim 1, characterized in that: The electrode module (1) comprises a central electrode (17), an extended wire harness (16) and a conductive wire (18); the conductive wire (18) and the extended wire harness (16) are respectively located at two ends of the central electrode (17); the extended wire harness (16) is connected to the central electrode (17); the conductive wire (18) is connected to the central electrode (17); and the conductive wire (18) is electrically connected to the electrical measurement module (3).

3. A device for measuring porosity of roadbed rock layer according to claim 2, characterized in that: The extended wire harness (16) comprises a clamping ring (162) and a plurality of electrode wires (161); the plurality of electrode wires (161) are arranged in a ring shape at the end of the central electrode (17); adjacent electrode wires (161) are arranged at intervals; the ends of the electrode wires (161) are hinged to the central electrode (17); the electrode wires (161) are connected to the clamping ring (162); and the diameter of the clamping ring (162) is adjustable.

4. The device for measuring the porosity of a roadbed rock layer according to claim 1, characterized in that: The energy supply device (6) comprises a solar panel and an energy storage battery, the solar panel is electrically connected to the energy storage battery, the power measurement module (3) is electrically connected to the energy storage battery, and the storage module (7) is electrically connected to the energy storage battery.

5. The device for measuring the porosity of a roadbed rock layer according to claim 1, characterized in that: The image acquisition module (2) comprises an automatic zoom camera device.

6. A method for determining the porosity of a roadbed rock layer, characterized in that: The device for measuring the porosity of a roadbed rock layer according to any one of claims 1 to 5 comprises the following steps: S1: Determine the positions of the survey lines (10) and the survey points (11): Set up a number of vertical rectangular observation surfaces, the rectangular observation surfaces are located in the rock layer (9), the area of ​​the rectangular observation surface is A, and survey lines (10) having the same length as the rectangular observation surface are set up in the rectangular observation surface; survey lines (10) L1, L2, L3, ... L are set up in different rectangular observation surfaces respectively. N , the measuring line (10) is set along the direction of the roadbed, and the spacing between adjacent measuring lines (10) in the roadbed width direction is ; setting a plurality of measuring points (11) at intervals on the measuring line (10); S2: Selecting the measuring line (10): Selecting the measuring line (10) L1 as the measuring line; S3: Arranging a collection mechanism: connecting the electrode module (1) and the image collection module (2) to form a collection mechanism, and respectively arranging the collection mechanisms at the measurement points (11) of the selected measurement line (10); S4: measuring the resistance data of the measuring point (11): adjusting the transformer voltage to obtain the resistance data of the measuring point (11) when the pore information reflected by the resistance data of the measuring point (11) is consistent with the pore information obtained by the image acquisition module (2); S5: Measure lines (10) L2, L3, ... L N Resistance data measurement: Repeat steps S3-S4 to obtain the resistance data of test lines (10) L2, L3, ... L N The resistance data of the measuring point (11) on the upper side are obtained, and multiple sets of data are recorded as follows: Wherein, X is the horizontal distance, Y is the depth, and R is the resistance value, and multiple sets of resistance data containing two-dimensional coordinates are obtained; S6: Obtaining the pore area of ​​the observation surface: Based on the resistance data of the measuring point (11) of the selected measuring line (10), obtain the cross-sectional resistance cloud map of the rectangular observation surface where the measuring line (10) is located, and divide the cross-sectional resistance cloud map into a number of squares. If the resistance of a square is greater than 1000Ω, it is determined that the square is air; the pore area in the cross section is , is the area of ​​the pore unit, R is the resistance data of the selected measuring point (11), is the total pore area, is the area of ​​the pore unit, R is the resistance data of the selected measuring point (11); S7: Calculate the total pore volume: by the formula Calculate the volume of total pores; S8: Porosity calculation: The total volume of the test rock layer (9) is known , then the total porosity of the block stone layer (9) roadbed , where n is the number of electrodes, A is the test cross-sectional area, and the calculation formula is: , L is the length of the test section, and D is the height of the test section, both of which are related to the number of electrodes; , a is the electrode spacing, the electrode spacing is a constant, D=k*a, k is a constant related to the electrode arrangement.

7. A method for determining the porosity of a roadbed rock layer according to claim 6, characterized in that: In S4, the voltage of the transformer module (5) is adjusted to 48V, 100V and 144V in sequence, and the resistance data of the measuring point (11) is selected when the pore information reflected by the resistance data is consistent with the pore information obtained by the image acquisition module (2).

8. The method for determining the porosity of a roadbed rock layer according to claim 6, characterized in that: In S7, using the formula , reduce ∆d in sequence to obtain V1, V2, V3...V n , until (V n -V n-1 ) / V n-1 When <1%, V n As the total pore volume V.

9. The method for determining the porosity of a roadbed rock layer according to claim 6, characterized in that: In S1, when inspecting an existing roadbed, the electrode module (1) is moved to a specified depth; when inspecting a newly built roadbed, the electrode module (1) is pre-buried at the interface between the block stone layer (9) and the upper fill layer.

10. The method for determining the porosity of a roadbed rock layer according to claim 6, characterized in that: In S1, the electrode module (1) is in close contact with the stone block.

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