Embankment evaluation system and embankment evaluation method
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- KAJIMA CORP
- Filing Date
- 2022-09-15
- Publication Date
- 2026-05-26
Smart Images
Figure 0007865841000001 
Figure 0007865841000002 
Figure 0007865841000003
Abstract
Description
[Technical Field]
[0001] This disclosure relates to an embankment evaluation system and an embankment evaluation method for evaluating embankments. [Background technology]
[0002] Patent Document 1 describes a vibratory roller to which an RI measuring device is attached via a mounting structure. The mounting structure extends downward between the front and rear wheels of the vibratory roller and comprises a first rotating body and a second rotating body, which are wheels placed on the roadbed. The first rotating body and the second rotating body are arranged front to back. The RI measuring device has a density measuring instrument housed inside the first rotating body and a moisture content measuring instrument housed inside the second rotating body.
[0003] Patent Document 2 describes a soil measuring device integrated with a compaction machine. The soil measuring device has a resistivity measuring unit for measuring the resistivity of the soil and a volumetric water content derivation unit for measuring the volumetric water content of the soil. The resistivity measuring unit measures the resistivity of the soil after compaction using electrodes positioned behind the compaction machine in the direction of travel. The dry density and water content of the soil are derived from the resistivity and volumetric water content.
[0004] Patent Document 3 describes a ground quality measuring device for measuring a roadbed, which is a ground body to be measured, made of compacted asphalt or the like on a base. The ground quality measuring device includes a vehicle that moves along the roadbed. The vehicle is equipped with an RI source and a detector. The RI source scatters and emits gamma rays downward. The detector detects the scattered and reflected gamma rays and electrically converts the gamma rays into pulse signals. The ground quality measuring device calculates the average density of the roadbed from the gamma rays that have been electrically converted into pulse signals.
[0005] Patent Document 4 describes a measurement system for the ground surface equipped with measurement instruments. The measurement instruments include a source unit having a γ-ray source and a neutron source, a fast neutron detection unit for measuring fast neutrons scattered on the ground surface, a thermal neutron detection unit for measuring thermal neutrons scattered on the ground surface, and a γ-ray detection unit for measuring γ-rays scattered on the ground surface. The moisture content of the ground surface is calculated from the counting rate of thermal neutrons, and the density of the ground surface is measured from the counting rate of γ-rays.
[0006] Patent Document 5 describes a system equipped with a surface scattering type moisture density meter which is a RI instrument and a ground penetrating radar that irradiates laser light from the ground surface into the ground. The surface scattering type moisture density meter measures the water content ratio and dry density in the vicinity of 10 cm from the ground surface. The ground penetrating radar measures the reflected wave of the laser light from underground and calculates the dry density and wet density by a calculation formula.
Prior Art Documents
Patent Documents
[0007]
Patent Document 1
Patent Document 2
Patent Document 3
Patent Document 4
Patent Document 5
Summary of the Invention
Problems to be Solved by the Invention
[0008] The aforementioned RI measuring device and soil measuring device are integrated with compaction machinery such as vibratory rollers. In the aforementioned ground quality measuring device and measuring system, the moisture content and density of the ground are calculated using neutron beams or gamma rays. In addition, the aforementioned system calculates the dry density and wet density of the ground from reflected waves measured by underground radar. However, when measuring the density of embankment using gamma rays, etc., the measurement is affected by the distance between the measuring device and the ground, so there is room for improvement in terms of the accuracy of measuring the density of embankment.
[0009] Furthermore, a method is known in which the distance between the measuring instrument and the ground is measured, and the density is calculated taking this distance into account. However, the distance between the measuring instrument and the ground can change frequently due to the influence of tracks left by heavy machinery or unevenness resulting from the mixing of materials with different particle sizes. In other words, since the distance between the measuring instrument and the ground is constantly changing due to unevenness, the accuracy of measuring the density of the embankment may not improve even if this distance is taken into account. Therefore, there is room for improvement in the accuracy of embankment evaluation as well.
[0010] This disclosure aims to provide an embankment evaluation system and an embankment evaluation method that can improve the accuracy of embankment evaluation. [Means for solving the problem]
[0011] The embankment evaluation system according to this disclosure comprises: (1) a resistivity measuring device having a pair of potential electrodes and a pair of current electrodes for measuring the resistivity of an embankment while facing the embankment; a volumetric moisture content measuring device having a scattering type RI moisture meter for measuring the volumetric moisture content of an embankment while facing the embankment; and an embankment evaluation item calculation unit that calculates at least one of the dry density of the embankment and the water content ratio of the embankment by combining the resistivity of the embankment measured by the resistivity measuring device and the measurement results from the scattering type RI moisture meter.
[0012] This embankment evaluation system is equipped with a resistivity measuring device, which measures the resistivity of the embankment using a pair of potential electrodes and a pair of current electrodes facing the embankment. By measuring the resistivity using a pair of potential electrodes and a pair of current electrodes facing the embankment in this way, the influence of the distance from the ground can be reduced compared to when using RI wires, etc. Therefore, the accuracy of measuring the dry density of the embankment can be improved. Furthermore, the embankment evaluation system is equipped with a volumetric moisture content measuring device and an embankment evaluation item calculation unit, which calculates at least one of the dry density and the moisture content of the embankment by combining the resistivity and the measurement results from a scattering-type RI moisture meter. In this way, by calculating at least one of the dry density and moisture content from the resistivity and the measurement results from a scattering-type RI moisture meter, the accuracy of measuring the dry density and moisture content can be improved.
[0013] (2) In (1) above, the embankment evaluation system may include an air porosity calculation unit that calculates the air porosity of the embankment from the resistivity of the embankment measured by a resistivity measuring device. The embankment evaluation item calculation unit may calculate at least one of the dry density of the embankment and the water content ratio of the embankment from the air porosity of the embankment calculated by the air porosity calculation unit and the volumetric water content of the embankment measured by a volumetric water content measuring device. In this case, the embankment evaluation system includes an air porosity calculation unit, which calculates the air porosity of the embankment from the resistivity of the embankment measured by a resistivity measuring device. Furthermore, the embankment evaluation system includes a volumetric water content measuring device and an embankment evaluation item calculation unit, which calculates at least one of the dry density of the embankment and the water content ratio of the embankment from the volumetric water content and the air porosity. Thus, by calculating at least one of the dry density and water content from the volumetric moisture content and air porosity, the measurement accuracy of the dry density and water content can be improved compared to directly calculating them from the volumetric moisture content and resistivity. In other words, while the relationship between resistivity and dry density is not uniquely determined due to the influence of volumetric moisture content, the relationship between resistivity and air porosity is uniquely determined. Therefore, by calculating the air porosity from resistivity and then calculating the dry density using the air porosity, the dry density can be calculated with even greater accuracy. That is, the accuracy is improved because it eliminates the need to select a calibration curve that is closest to the actual volumetric moisture content (showing the relationship between resistivity and dry density).
[0014] (3) In (1) or (2) above, the pair of potential electrodes and the pair of current electrodes may be capacitor electrodes. In this case, the effects of drying and other factors can be reduced, and the accuracy of resistivity measurement can be improved.
[0015] (4) In any of (1) to (3) above, the resistivity measuring device may have a plurality of electrode holding parts that hold each of the pair of potential electrodes and the pair of current electrodes facing the embankment, and a plurality of spring mechanisms provided corresponding to each of the plurality of electrode holding parts that bias each electrode holding part toward the embankment. In this case, the electrode holding parts that hold each of the pair of potential electrodes and the pair of current electrodes facing the embankment are biased toward the embankment by the spring mechanism. Therefore, each of the pair of potential electrodes and the pair of current electrodes is biased by the spring mechanism to be pressed against the embankment, so that each potential electrode and each current electrode can follow the embankment even if there is unevenness. Thus, the resistivity of the embankment can be measured easily and with high accuracy.
[0016] (5) In any of (1) to (4) above, the embankment evaluation system may include a first linear body connecting the resistivity measuring device and the volumetric moisture content measuring device to each other, and a second linear body extending from either the resistivity measuring device or the volumetric moisture content measuring device. The resistivity measuring device and the volumetric moisture content measuring device may be pulled on the embankment by the second linear body being pulled. In this case, the resistivity measuring device and the volumetric moisture content measuring device are connected to each other via the first linear body, and the second linear body extends from either the resistivity measuring device or the volumetric moisture content measuring device. Therefore, the resistivity measuring device and the volumetric moisture content measuring device can be driven on the embankment by the second linear body being pulled, and resistivity and volumetric moisture content can be measured while the resistivity measuring device and the volumetric moisture content measuring device are driving together. Thus, at least one of the dry density and moisture content can be evaluated on the embankment surface, so the embankment can be evaluated efficiently and with high accuracy.
[0017] The embankment evaluation method according to this disclosure comprises (6) the steps of: measuring the resistivity of the embankment using a pair of potential electrodes and a pair of current electrodes facing the embankment; measuring the volumetric water content of the embankment using a scattering-type RI moisture meter facing the embankment; calculating the air porosity of the embankment from the resistivity of the embankment; and calculating at least one of the dry density of the embankment and the water content ratio of the embankment from the air porosity of the embankment and the volumetric water content of the embankment.
[0018] In this embankment evaluation method, in the process of measuring resistivity, a pair of potential electrodes and a pair of current electrodes facing the embankment measure the resistivity of the embankment. Therefore, compared to the case using RI lines, etc., it is possible to reduce the influence of the distance from the ground. Consequently, the accuracy of measuring the dry density of the embankment can be improved. The embankment evaluation method includes a step of calculating the air porosity, which is calculated from the resistivity. Furthermore, the embankment evaluation method includes a step of measuring the volumetric moisture content, and at least one of the dry density of the embankment and the moisture content ratio of the embankment is calculated from the air porosity and volumetric moisture content. As mentioned above, the relationship between resistivity and dry density is not uniquely determined due to the influence of volumetric moisture content, whereas the relationship between resistivity and air porosity is uniquely determined. Therefore, by calculating the dry density using the air porosity calculated from resistivity, the dry density can be measured with even greater accuracy. The accuracy is improved by eliminating the need to select a calibration curve that is closest to the volumetric moisture content at the site (showing the relationship between resistivity and dry density).
[0019] (7) In (6) above, the embankment evaluation method comprises the steps of conducting a compaction test of the embankment before the embankment is constructed and obtaining the relationship between the resistivity and air porosity of the embankment, and the steps of conducting the compaction test and obtaining the relationship may be performed simultaneously. In this case, the relationship between resistivity and air porosity can be obtained together with the compaction test conducted before the construction of the embankment. Therefore, since the relationship between resistivity and air porosity can be obtained before the construction of the embankment, the measurement of the embankment and the evaluation of the quality of the embankment can be performed more efficiently.
[0020] (8) In the embankment evaluation method described in (6) or (7) above, the method may include a resistivity measuring device having a pair of potential electrodes and a pair of current electrodes, and a volumetric moisture content measuring device having a scattering type RI moisture meter. The steps of measuring resistivity and measuring volumetric moisture content may be performed while the resistivity measuring device and the volumetric moisture content measuring device are towed on the embankment. In this case, the resistivity measuring device and the volumetric moisture content measuring device are towed on the embankment while the resistivity measuring device and the volumetric moisture content measuring device are measured. Therefore, while moving on the embankment, resistivity and volumetric moisture content can be measured, and the dry density and water content can be calculated from the air void ratio and volumetric moisture content. Thus, since at least one of the dry density and water content can be evaluated on a surface basis with respect to the embankment, the embankment can be evaluated efficiently and with high accuracy. [Effects of the Invention]
[0021] According to this disclosure, the accuracy of embankment evaluation can be improved. [Brief explanation of the drawing]
[0022] [Figure 1] This is a perspective view showing a specific example of the embankment evaluation system according to the embodiment. [Figure 2] Figure 1 is a schematic plan view showing the resistivity measurement device of the embankment evaluation system. [Figure 3] Figure 2 schematically shows the electrode configuration of the resistivity measuring device. [Figure 4] Figure 2 is a perspective view showing the electrodes, electrode holder, and spring mechanism of the resistivity measuring device. [Figure 5] Figure 1 is a schematic longitudinal cross-sectional view of the volumetric water content measuring device of the embankment evaluation system. [Figure 6] This graph shows the relationship between the volumetric water content of the embankment and the number of thermal neutrons detected. [Figure 7] This graph shows an example of a calibration curve illustrating the relationship between air porosity and resistivity. [Figure 8] Figure 7 is a schematic perspective view showing the calibration curve acquisition device used to obtain the calibration curve. [Figure 9]This flowchart shows an example of the steps in the embankment evaluation method according to the embodiment. [Figure 10] This is a perspective view showing a resistivity measuring device related to a modified example. [Modes for carrying out the invention]
[0023] The embodiments of the embankment evaluation system and embankment evaluation method relating to this disclosure will be described below with reference to the drawings. In the description of the drawings, the same or equivalent elements are denoted by the same reference numeral, and redundant explanations are omitted as appropriate. For the sake of ease of understanding, some parts of the drawings may be simplified or exaggerated, and the dimensional ratios, etc., are not limited to those shown in the drawings.
[0024] The embankment evaluation system 1 according to this embodiment is used, for example, at site A where a dam is constructed. At site A, for example, soil is transported by dump trucks, the transported soil is spread out by bulldozers, and the spread soil is compacted by vibratory rollers. The vibratory roller compacts the soil by moving back and forth multiple times at site A, thereby compacting the embankment B at site A.
[0025] The embankment evaluation system 1 evaluates the embankment B (soil) at site A while moving along the ground S, which is the compacted surface after compaction by a compaction machine such as a vibratory roller. Ground S is the construction surface formed by compaction. The embankment evaluation system 1 calculates, for example, at least one of the dry density of embankment B and the water content of embankment B as evaluation items for embankment B.
[0026] For example, the embankment evaluation system 1 evaluates embankment B by measuring its dry density and water content, and measures, for example, the effect of compaction by a compaction machine. Embankment B may be composed of, for example, CSG, RCD, or cover soil from a radioactive disposal project.
[0027] For example, the embankment evaluation system 1 includes a resistivity measuring device 10 for measuring the resistivity of embankment B, and a volumetric moisture content measuring device 15 for measuring the volumetric moisture content of embankment B. Furthermore, the embankment evaluation system 1 includes an air porosity calculation unit 31 for calculating the air porosity of embankment B from the resistivity of embankment B, and an embankment evaluation item calculation unit 32 for calculating the dry density of embankment B and the moisture content ratio of embankment B.
[0028] For example, the embankment evaluation system 1 includes a first linear body 2 that connects the resistivity measuring device 10 and the volumetric water content measuring device 15 to each other, and a second linear body 3 that extends from the resistivity measuring device 10. As an example, the first linear body 2 and the second linear body 3 are each string-like bodies. For example, the embankment evaluation system 1 includes a traction section 30 provided on the side opposite to the volumetric water content measuring device 15 when viewed from the resistivity measuring device 10.
[0029] The traction unit 30 includes, for example, a plurality of wheels 30b, a base 30c connecting the upper parts of the plurality of wheels 30b, and a handle 30d extending upward from the base 30c. The base 30c is connected to the resistivity measuring device 10, and by holding the handle 30d with the wheels 30b on the ground S and rolling the wheels 30b on the ground S, the traction unit 30, the resistivity measuring device 10, and the volumetric water content measuring device 15 can be moved on the ground S. For example, the air void ratio calculation unit 31 and the embankment evaluation item calculation unit 32 are provided on the base 30c. However, the location of the air void ratio calculation unit 31 and the embankment evaluation item calculation unit 32 is not particularly limited.
[0030] Figure 2 is a plan view showing the resistivity measuring device 10. The resistivity measuring device 10 is, for example, a portable electrical resistance measuring device. That is, the resistivity measuring device 10 is a portable device. The resistivity measuring device 10 measures the resistivity of the embankment B at site A while moving along the ground S after it has been compacted by a compaction machine.
[0031] The resistivity measuring device 10 is equipped with four electrodes 20, which are capacitor electrodes. For example, the arrangement of the electrodes 20 in the resistivity measuring device 10 conforms to the dipole-dipole method. The four electrodes 20 consist of a pair of potential electrodes 21 and a pair of current electrodes 22. The resistivity measuring device 10 measures the resistivity of the embankment B using the four-electrode method. Each of the potential electrodes 21 and current electrodes 22 is positioned close to the ground S.
[0032] A pair of potential electrodes 21 and a pair of current electrodes 22 are arranged to be aligned along a first direction D1, which is the direction of movement of the resistivity measuring device 10. For example, the pair of potential electrodes 21 are positioned in front of the resistivity measuring device 10 in the direction of movement, and the pair of current electrodes 22 are positioned behind it in the same direction of movement. For example, the pair of potential electrodes 21 and the pair of current electrodes 22 are arranged in a dipole-dipole configuration. However, the arrangement of the pair of potential electrodes 21 and the pair of current electrodes 22 may be in a configuration other than a dipole-dipole configuration, and is not particularly limited.
[0033] Figure 3 is a schematic diagram of the configuration of the electrodes 20 in the resistivity measuring device 10. As shown in Figure 3, the potential electrode 21 and the current electrode 22 are dragged, for example, on the ground S. Each of the potential electrode 21 and the current electrode 22 has a dielectric 23 facing the ground S and a conductor 24 electrically connected to the dielectric 23. The dielectric 23 is, for example, a plate-shaped member made of synthetic resin.
[0034] Since the dielectric 23 is in contact with the ground S and dragged on the ground S, it is preferable that it be made of a material that can withstand contact with the ground S. The dielectric 23 includes, for example, at least one of high-density polyethylene, rigid polyurethane, and ABS (Acrylonitrile Butadiene Styrene) resin.
[0035] The conductor 24 is a flat plate containing a conductive metal. The resistivity measuring device 10 further includes an AC power supply 25 and a potentiometer 26. The AC power supply 25 is electrically connected to the conductor 24 of each current electrode 22. The potentiometer 26 is electrically connected to the conductor 24 of each potential electrode 21.
[0036] The AC power supply 25 applies an AC voltage between the pair of current electrodes 22. This causes an AC current to flow through the embankment B. For example, when a voltage is applied to the conductors 24 of the pair of current electrodes 22 that are not in contact with the ground S, charge accumulates between the conductors 24 and the embankment B, and the current electrodes 22 become capacitors. If the AC power supply 25 switches the polarity of the voltage before the capacitor-like current electrodes 22 are fully charged or discharged, an AC current will flow continuously through the embankment B, which has resistance. The potentiometer 26 measures the potential between the pair of potential electrodes 21, which have become capacitors similar to the current electrodes 22.
[0037] Figure 4 is an enlarged perspective view of a part of the resistivity measuring device 10. As shown in Figures 2 and 4, the resistivity measuring device 10 includes the aforementioned electrode 20, a holder 41 extending in a first direction D1 and a second direction D2 that is along the ground S and intersects the first direction D1, and a plurality of casters 42 that support the holder 41 so that it can move when the holder 41 is separated from the ground S. The second direction D2 is, for example, a direction perpendicular to the first direction D1.
[0038] The electrode 20 is located below the holder 41. The holder 41 is plate-shaped and extends in a first direction D1 and a second direction D2. In this case, the holder 41 has thickness in a third direction D3 that intersects both the first direction D1 and the second direction D2. For example, the third direction D3 is vertical. As an example, the holder 41 is rectangular plate-shaped. Casters 42 are provided, for example, at each of the four corners of the holder 41 in a plan view. The resistivity measuring device 10 includes, for example, a handle portion 44 that is gripped when the holder 41 is lifted.
[0039] The handle portion 44 is fixed, for example, to the upper surface 41b of the holder 41. Each handle portion 44 extends in a first direction D1. The holder 41 has, for example, two handle portions 44, and the two handle portions 44 are aligned in a second direction D2. Therefore, a worker performing quality measurement work on the embankment B can easily lift the holder 41 by holding the handle portions 44 with both hands.
[0040] For example, each of the multiple electrodes 20 is arranged so as to be aligned along a first direction D1 in a plan view. The resistivity measuring device 10 has, for example, two holders 41 and a linear body 48 extending in the first direction D1 between the two holders 41. The linear body 48 is, for example, detachable from the holders 41. When this linear body 48 is provided, when one of the two holders 41 (for example, the holder 41 that holds the potential electrode 21) is pulled in the first direction D1, one of the two holders 41 and the other can be moved in the first direction D1. In addition, by preparing multiple types of linear bodies 48 with different lengths and attaching a selected linear body 48 from the multiple types of linear bodies 48, the distance X between the potential electrode 21 and the current electrode 22 can be changed. The distance X represents the distance from the center of the potential electrode 21 to the center of the current electrode 22 (center-to-center distance).
[0041] The resistivity measuring device 10 includes a variable mechanism 45 that changes the distance between a pair of potential electrodes 21 and a pair of current electrodes 22. The resistivity measuring device 10 has, for example, a plurality of variable mechanisms 45. Each of the plurality of variable mechanisms 45 changes the distance X between the potential electrodes 21 and the current electrodes 22, and the distance Y between the pair of potential electrodes 21 (or the pair of current electrodes 22). The distance Y represents the distance from the center of one potential electrode 21 (or one current electrode 22) to the center of the other potential electrode 21 (or the other current electrode 22) (center-to-center distance).
[0042] The variable mechanism 45 includes, for example, a slit 45b that penetrates the holder 41, a rod-shaped portion 45c that is inserted through the slit 45b and movable along the slit 45b, and a stopper portion 45d that stops the rod-shaped portion 45c at the upper part of the slit 45b. Each of the multiple slits 45b extends, for example, in a first direction D1. The potential electrode 21 and the current electrode 22 are each provided below the rod-shaped portion 45c. Therefore, the distance X and the spacing Y can be changed by moving the rod-shaped portion 45c along the slit 45b. Note that the configuration of the variable mechanism is not limited to the variable mechanism 45 described above.
[0043] As described above, the resistivity measuring device 10 allows for the adjustment of the distance X between the potential electrode 21 and the current electrode 22, and the spacing Y between the pair of potential electrodes 21 (or between the pair of current electrodes 22). When resistivity is measured by the pair of potential electrodes 21 and the pair of current electrodes 22, the measurement depth in the embankment B depends on the distance X and the spacing Y. Therefore, by making the distance X and the spacing Y variable, it becomes possible to vary the measurement depth of resistivity in the embankment B. Thus, since the measurement depth of resistivity can be easily changed, the quality evaluation of the embankment B can be performed more efficiently and with greater accuracy.
[0044] The holder 41 includes a plurality of electrode holding parts 43 that hold each of the pair of potential electrodes 21 and the pair of current electrodes 22 facing the embankment B. For example, the electrode holding part 43 has a plate-shaped part 43c connected to the lower end of a rod-shaped part 45c, a rod-shaped part 43d inserted through the plate-shaped part 43c in a third direction D3, and an electrode mounting part 43f connected to the lower end of the rod-shaped part 43d. The plate-shaped part 43c extends in a first direction D1 and a second direction D2 at the lower ends of the plurality of rod-shaped parts 45c. The electrode holding part 43 has a plurality of rod-shaped parts 43d. Each of the plurality of rod-shaped parts 43d is movable in the third direction D3 in each of the plurality of holes 43g formed in the plate-shaped part 43c.
[0045] The electrode mounting portion 43f is connected to the lower ends of multiple rod-shaped portions 43d and moves in the third direction D3 as each rod-shaped portion 43d moves in the third direction D3. The electrode mounting portion 43f is, for example, frame-shaped, extending in the first direction D1 and the second direction D2, and the electrode 20 is attached to the frame-shaped portion of the electrode mounting portion 43f. For example, the upper surface 20b and lower surface of the electrode 20 are exposed from the electrode mounting portion 43f.
[0046] For example, the electrode mounting portion 43f has a rectangular shape extending in a first direction D1 and a second direction D2. The electrode holding portion 43 has, for example, a crossover portion 43h that can overcome protrusions in the ground S. The crossover portion 43h has a triangular prism shape extending in the second direction D2 from one end of the electrode mounting portion 43f in the first direction D1. By providing the crossover portion 43h, the holder 41 can overcome protrusions in the ground S even if they exist in the first direction D1.
[0047] The resistivity measuring device 10 has multiple spring mechanisms 46 provided in accordance with the multiple electrode holding parts 43, and biasing each electrode holding part 43 toward the embankment B side (downward). The spring mechanism 46 has, for example, the aforementioned hole 43g, a rod-shaped part 43d inserted through the hole 43g, and a spring 47 surrounding the rod-shaped part 43d.
[0048] One end (upper end) of the spring 47 abuts against the plate-shaped portion 43c, and the other end (lower end) of the spring 47 abuts against the electrode mounting portion 43f. The spring 47 biases the electrode mounting portion 43f toward the embankment B. When the holder 41 travels and encounters unevenness on the ground S, the overcoming portion 43h overcomes the unevenness, causing the electrode mounting portion 43f and the electrode 20 to come into contact with the unevenness, and the electrode mounting portion 43f and the rod-shaped portion 43d move in a third direction D3 relative to the plate-shaped portion 43c. At this time, since the spring 47 biases the electrode mounting portion 43f and the electrode 20 toward the embankment B, even if there is unevenness on the ground S, it is possible to overcome the unevenness and make the electrode mounting portion 43f and the electrode 20 follow the unevenness.
[0049] As shown in Figure 1, for example, the volumetric moisture content measuring device 15 includes a scattering-type RI moisture meter 16, a traveling body 17, and a holding part 18 that holds the scattering-type RI moisture meter 16 while attached to the lower surface of the traveling body 17. The traveling body 17 has a plurality of wheels 17b and a base portion 17c provided on the upper part of the plurality of wheels 17b.
[0050] For example, the holding part 18 is attached to the lower surface of the base part 17c with the scattering type RI moisture meter 16 held inside. The holding part 18 is made of metal, for example. The holding part 18 has a recess in which the scattering type RI moisture meter 16 is housed, and the lower surface of the recess is in contact with the ground S. The scattering type RI moisture meter 16 measures the volumetric water content of the embankment B while in contact with the ground S via the lower surface.
[0051] Figure 5 is a schematic longitudinal cross-sectional view showing the scattering-type RI moisture meter 16 and the embankment B. As shown in Figures 1 and 5, the scattering-type RI moisture meter 16 measures the volumetric water content of the embankment B while facing the embankment B. The scattering-type RI moisture meter 16 moves on the ground S simultaneously with, or immediately after, the movement of the resistivity measuring device 10, to measure the volumetric water content.
[0052] The scattering-type RI moisture meter 16 comprises a neutron source 16b, a thermal neutron detection unit 16c, and a housing 16d that accommodates the neutron source 16b and the thermal neutron detection unit 16c. As an example, the neutron source 16b is located below the thermal neutron detection unit 16c. The neutron source 16b emits fast neutrons Z1 into the embankment B.
[0053] Fast neutrons Z1 emitted from embankment B are scattered. Some of the scattered fast neutrons Z1 collide with hydrogen atoms B1 in embankment B. Fast neutrons Z1 that collide with hydrogen atoms B1 lose their velocity and become thermal neutrons Z2. The thermal neutron detection unit 16c measures the volumetric water content by detecting the thermal neutrons Z2 generated in embankment B.
[0054] If the volumetric moisture content is denoted as θ, the relationship between the volumetric moisture content θ and the number of thermal neutrons Z2 detected by the thermal neutron detection unit 16c is shown in a graph like the one in Figure 6. The more thermal neutrons Z2 detected by the thermal neutron detection unit 16c, the larger the volumetric moisture content θ is, and the fewer thermal neutrons Z2 detected by the thermal neutron detection unit 16c, the smaller the volumetric moisture content θ is. The scattering-type RI moisture meter 16 can determine the volumetric moisture content θ by having the neutron source 16b emit fast neutrons Z1 into the embankment B and having the thermal neutron detection unit 16c detect the thermal neutrons Z2.
[0055] Incidentally, with transmission-type RI measuring instruments, the source rod must be inserted into the embankment B, making it difficult to measure the volumetric water content θ while moving on the ground S. In contrast, with scattering-type RI moisture meter 16, there is no need to insert the source rod or the like into the embankment B; the volumetric water content θ of the embankment B can be measured simply by placing it on the ground S.
[0056] Furthermore, as mentioned above, the resistivity measuring device 10 does not require insertion into the embankment B; it can measure the resistivity of embankment B simply by being placed on the ground S. Therefore, the embankment evaluation system 1 can measure the resistivity of embankment B and the volumetric water content θ of embankment B while traveling on the ground S, without inserting source rods or the like into embankment B.
[0057] As shown in Figure 1, the air porosity calculation unit 31 is capable of communicating with, for example, the resistivity measuring device 10. As illustrated in Figure 7, the air porosity V of the embankment B a Using a calibration curve L which shows the relationship between the resistivity and resistivity ρ, the air porosity calculation unit 31 calculates the air porosity V from the resistivity ρ measured by the resistivity measuring device 10. a The calibration curve L is calculated using resistivity ρ and air porosity V. a This is a unique correlation in soil mechanics that is determined independently of the water content of embankment B.
[0058] The calibration curve L is determined in advance, for example, before the quality evaluation of embankment B. As shown in Figure 8, for example, the calibration curve L is determined by a calibration curve acquisition device 50 that houses the embankment material C used in the construction of embankment B. For example, the calibration curve acquisition device 50 has a bottomed cylindrical shape.
[0059] For example, the inner diameter of the calibration curve acquisition device 50 is 300 mm, and the internal height of the calibration curve acquisition device 50 (height in the axial direction (up and down direction in Figure 8)) is 600 mm. The calibration curve acquisition device 50 includes a first electrode 51 located at the bottom 50b of the calibration curve acquisition device 50, a second electrode 52 located at the lid 50c of the calibration curve acquisition device 50, and a third electrode 53 and a fourth electrode 54 located on the side 50d of the calibration curve acquisition device 50, aligned along the axial direction J of the calibration curve acquisition device 50.
[0060] For example, the first electrode 51 and the second electrode 52 are sheets made of aluminum. The calibration curve acquisition device 50, with the embankment material C contained within, has a lid 50c having the second electrode 52 placed on the upper end of the side portion 50d, and current is passed between the first electrode 51 and the second electrode 52. The lid 50c may also be placed inside the cylindrical portion of the calibration curve acquisition device 50 and on top of the embankment material C. Specifically, the dry density ρ of the embankment B (embankment material C) d Furthermore, using the water content w of embankment B (embankment material C) as a parameter, embankment material C is statically compacted and current is passed between the first electrode 51 and the second electrode 52. At this time, the calibration curve acquisition device 50 measures the potential difference between the third electrode 53 and the fourth electrode 54 to obtain a predetermined air void ratio V a The resistivity ρ is obtained.
[0061] The resistivity ρ can be calculated, for example, from the following equation (1), and the air porosity V a It can be calculated from the following equation (2). ρ(Ω·m) = (measured potential difference / current flowed) × (Cross-sectional area of embankment material C / distance from the third electrode 53 to the fourth electrode 54) ... (1) V a =100(1-(ρd / ρ s )) - (w × ρ d ) ··· (2)
[0062] Incidentally, ρ s is the soil particle density of the material of the embankment B. ρ s is a basic physical property value of the soil and can be easily obtained in soil tests and the like. The water content ratio w of the embankment material C inside the calibration curve acquisition device 50 is obtained, for example, by the furnace drying method after measuring the specific resistance ρ. Also, from the volume of the calibration curve acquisition device 50, the wet weight of the embankment material C inside the calibration curve acquisition device 50, and the water content ratio w, the dry density ρ d is calculated.
[0063] Above, an example of obtaining the calibration curve L in advance using the calibration curve acquisition device 50 has been described. However, the method of obtaining the calibration curve L may also be a method that does not use the calibration curve acquisition device 50. For example, the calibration curve L may be obtained in the rolling compaction test (the process of performing the rolling compaction test) carried out before the construction of the embankment B. For example, in the rolling compaction test, the specific resistance ρ is measured by a specific resistance measurement device equipped with a capacitor electrode similar to the potential electrode 21 and the current electrode 22 described above to obtain the calibration curve L.
[0064] The rolling compaction test is carried out for the purpose of obtaining the number of running times with the highest compaction accuracy, using the number of running times of the embankment B by the compaction machine as a parameter. In the number of running times of the compaction machine, as the dry density ρ d of the embankment B increases and the air void ratio V a decreases, for example, the specific resistance ρ may be measured every time the compaction machine runs once. And, for example, the calibration curve L is obtained by obtaining the water content ratio w and the dry density ρ d by the sand replacement method.
[0065] The embankment evaluation item calculation unit 32 calculates the dry density ρ d of the embankment B and the water content ratio w of the embankment B from the air void ratio Va and the volume water content θ of the embankment B measured by the volume water content measuring device 15. The embankment evaluation item calculation unit 32 uses, for example, the following formula (3) to calculate the dry density ρ dCalculate (θ is volumetric water content, V) a ρ is the air porosity. s (This refers to soil particle density). θ+V a +(ρ d / ρ s )=1 ···(3) The embankment evaluation item calculation unit 32 calculates the water content w using, for example, the following formula (4) (ρ w This is the weight per unit volume of water (usually 1). θ=(ρ d / ρ w ) × (w / 100) ... (4)
[0066] Next, the embankment evaluation method according to this embodiment will be explained with reference to the flowchart in Figure 9. The embankment evaluation method according to this embodiment is performed, for example, using the embankment evaluation system 1 shown in Figure 1. First, the resistivity measuring device 10 and the volumetric water content measuring device 15 are placed on the ground S of the embankment B. For example, the resistivity measuring device 10 and the volumetric water content measuring device 15 are pulled on the ground S along the first direction D1 by pushing the traction unit 30.
[0067] At this time, the resistivity measuring device 10 measures the resistivity ρ of the embankment B (the process of measuring resistivity, step S1). Specifically, a pair of potential electrodes 21 and a pair of current electrodes 22 facing the embankment B measure the resistivity ρ of the embankment B. Then, the air porosity calculation unit 31 calculates the air porosity V of the embankment B from the resistivity ρ of the embankment B measured by the resistivity measuring device 10. a The air void ratio calculation unit 31 calculates the air void ratio V from the resistivity ρ measured by the resistivity measuring device 10 using, for example, a calibration curve L (see Figure 7) that has been acquired in advance. a Calculate.
[0068] Furthermore, the volumetric moisture content measuring device 15 measures the volumetric moisture content θ of the embankment B (step S3, step of measuring volumetric moisture content). At this time, the scattering-type RI moisture meter 16, which is facing the embankment B, measures the volumetric moisture content θ of the embankment B. Note that the measurement of volumetric moisture content θ by the volumetric moisture content measuring device 15 is performed simultaneously with the measurement of resistivity ρ by the resistivity measuring device 10, for example. For example, the resistivity measuring device 10 and the volumetric moisture content measuring device 15 may each measure resistivity ρ and volumetric moisture content θ while traveling over the embankment B.
[0069] Next, the embankment evaluation item calculation unit 32 calculates the air void ratio V a And the dry density ρ of embankment B from the volumetric water content θ d The calculation is performed (calculation process, step S4). For example, the embankment evaluation item calculation unit 32 uses the aforementioned formula (3) to calculate the volumetric water content θ and the air void ratio V. a and soil particle density ρ s From dry density ρ d The embankment evaluation item calculation unit 32 then calculates the water content w (calculation process, step S5). For example, the embankment evaluation item calculation unit 32 uses the aforementioned formula (4) to calculate the volumetric water content θ and the dry density ρ. d , and the weight ρ per unit volume of water w The water content w is calculated from this.
[0070] For example, the dry density ρ calculated by the embankment evaluation item calculation unit 32 d The calculation of the dry density ρ, and the calculation of the water content w by the embankment evaluation item calculation unit 32, are performed continuously while the embankment evaluation system 1 (resistivity measuring device 10 and volumetric water content measuring device 15) is traveling over the embankment B. In this case, the dry density ρ is calculated across the embankment B. d This also makes it possible to calculate the water content w.
[0071] For example, the embankment evaluation system 1 (a traction unit 30 as an example) may be equipped with a GNSS antenna, and the dry density ρ is linked to the positional information of the embankment B measured by the GNSS antenna. d The water content w may also be calculated. The embankment evaluation system 1 calculates the dry density ρ in embankment B. dFurthermore, mapping data for the water content w may be generated and displayed.
[0072] In this case, the dry density ρ is distributed throughout the entire embankment B. d Since data on the water content w can be obtained, the overall accuracy of the compaction of embankment B can be evaluated. Furthermore, the embankment evaluation system 1 obtains dry density ρ along with camera images of embankment B. d Furthermore, mapping data of the water content w may be displayed using AR. In this case as well, it is possible to grasp information about the overall quality of embankment B at a glance. As described above, dry density ρ d The series of steps is completed after the calculation of the water content w.
[0073] Next, the effects and advantages obtained from the embankment evaluation system 1 and embankment evaluation method according to this embodiment will be described in more detail. The embankment evaluation system 1 and embankment evaluation method according to this embodiment include a resistivity measuring device 10, which measures the resistivity ρ of the embankment B using a pair of potential electrodes 21 and a pair of current electrodes 22 facing the embankment B. In this way, by measuring the resistivity ρ with a pair of potential electrodes 21 and a pair of current electrodes 22 facing the embankment B, the influence of the distance from the ground S can be reduced compared to the case where RI lines or the like are used. Therefore, the dry density ρ of the embankment B d This can improve measurement accuracy.
[0074] The embankment evaluation system 1 includes an air porosity calculation unit 31, which calculates the air porosity V of embankment B from the resistivity ρ of embankment B measured by the resistivity measuring device 10. a The system calculates the following. Furthermore, the embankment evaluation system 1 includes a volumetric water content measuring device 15 and an embankment evaluation item calculation unit 32. The embankment evaluation item calculation unit 32 calculates at least one of the dry density of embankment B and the water content of embankment B by combining resistivity and measurement results from a scattering-type RI moisture meter 16. For example, the embankment evaluation item calculation unit 32 calculates the volumetric water content θ and the air porosity V a Dry density ρ of embankment B d , and calculate at least one of the water content w of embankment B. In this way, calculate the volumetric water content θ and the air porosity Va From dry density ρ d By calculating at least one of the volumetric water content θ and water content w, the dry density ρ can be directly obtained from the volumetric water content θ and resistivity ρ. d And compared to the case where the water content w is calculated, the dry density ρ d Furthermore, the accuracy of measuring the water content w can be improved.
[0075] By the way, resistivity ρ and dry density ρ d The relationship between resistivity ρ and air porosity Va is not uniquely determined due to the influence of the volumetric water content θ. In contrast, as shown in Figure 7, the relationship between resistivity ρ and air porosity Va is uniquely determined, so from resistivity ρ to air porosity Va a The air porosity V is calculated. a Using dry density ρ d By calculating the dry density ρ, d It is possible to calculate this with high accuracy. In other words, the value that is closest to the volumetric moisture content θ at the site (resistivity ρ and dry density ρ) d The accuracy improves because we no longer need to select a calibration curve (which shows the relationship with the given data).
[0076] In this embodiment, the pair of potential electrodes 21 and the pair of current electrodes 22 are capacitor electrodes. Therefore, they are less susceptible to the effects of drying and other factors, and thus the measurement accuracy of resistivity ρ can be improved.
[0077] In this embodiment, as shown in Figures 3 and 4, the resistivity measuring device 10 includes a plurality of electrode holding parts 43 that hold each of the pair of potential electrodes 21 and the pair of current electrodes 22 facing the embankment B, and a plurality of spring mechanisms 46 provided corresponding to each of the plurality of electrode holding parts 43 that bias each electrode holding part 43 toward the embankment B. Thus, the electrode holding parts 43 that hold each of the pair of potential electrodes 21 and the pair of current electrodes 22 facing the embankment B are biased toward the embankment B by the spring mechanisms 46. Consequently, each of the pair of potential electrodes 21 and the pair of current electrodes 22 is biased by the spring mechanisms 46 to be pressed against the embankment B, so that each potential electrode 21 and each current electrode 22 can follow the embankment B even if there is unevenness. Thus, the resistivity of the embankment B can be measured easily and with high accuracy.
[0078] In this embodiment, as shown in Figure 1, the embankment evaluation system 1 includes a first linear body 2 that connects the resistivity measuring device 10 and the volumetric moisture content measuring device 15 to each other, and a second linear body 3 that extends from the resistivity measuring device 10. The resistivity measuring device 10 and the volumetric moisture content measuring device 15 are pulled on the ground S by the second linear body 3 being pulled. Thus, the resistivity measuring device 10 and the volumetric moisture content measuring device 15 are connected to each other via the first linear body 2. The second linear body 3 extends from the resistivity measuring device 10. Therefore, the resistivity measuring device 10 and the volumetric moisture content measuring device 15 can be driven on the embankment B by the second linear body 3 being pulled, and the resistivity ρ and volumetric moisture content θ can be measured while the resistivity measuring device 10 and the volumetric moisture content measuring device 15 are driving together. Thus, the dry density ρ can be measured across the embankment B. d Furthermore, since the water content w can be evaluated, the embankment B can be evaluated efficiently and with high accuracy.
[0079] The embankment evaluation method according to this embodiment includes the steps of performing a compaction test on embankment B before construction, and the resistivity ρ and air porosity V of embankment B. aThe process includes a step of obtaining a relationship (e.g., calibration curve L) with respect to resistivity ρ and air porosity V, and the steps of conducting a compaction test and obtaining the relationship may be performed simultaneously. In this case, the resistivity ρ and air porosity V are obtained together with the compaction test conducted before the construction of the embankment B. a The relationship between resistivity ρ and air porosity V can be obtained. Therefore, the relationship between resistivity ρ and air porosity V can be obtained. a Since the relationship can be obtained before construction of embankment B, measurement of embankment B and quality evaluation of embankment B can be performed more efficiently.
[0080] The embankment evaluation method according to this embodiment includes a resistivity measuring device 10 having a pair of potential electrodes 21 and a pair of current electrodes 22, and a volumetric moisture content measuring device 15 having a scattering-type RI moisture meter 16. The steps of measuring resistivity ρ and measuring volumetric moisture content θ are performed while the resistivity measuring device 10 and the volumetric moisture content measuring device 15 are towed on the embankment B. Therefore, resistivity ρ and volumetric moisture content θ are measured while the resistivity measuring device 10 and the volumetric moisture content measuring device 15 are towed on the embankment B. Thus, since resistivity ρ and volumetric moisture content θ are measured while moving on the embankment B, the air porosity V a And dry density ρ from volumetric water content θ d Furthermore, the water content w can be calculated efficiently. Therefore, the dry density ρ can be calculated across the surface of embankment B. d Since it is possible to evaluate at least one of the following: and the water content w, the evaluation of embankment B can be performed efficiently and with high accuracy.
[0081] Next, a modified embankment evaluation system will be described with reference to Figure 10. Figure 10 is a perspective view showing the resistivity measuring device 60 of the modified embankment evaluation system. The resistivity measuring device 60 is used, for example, in place of the resistivity measuring device 10. As shown in Figure 10, the resistivity measuring device 60 is equipped with four electrodes 61 which are wheel-type electrodes. The resistivity measuring device 60 is equipped with a rod-shaped shaft 62, two wheels 63 rotatably connected to each end of the shaft 62, and four electrode support parts 64 extending from the shaft 62 in a direction intersecting the extending direction of the shaft 62, with each electrode 61 being supported by each electrode support part 64.
[0082] Each electrode 61, supported by the electrode support 64, measures its resistivity facing the ground S of the embankment B, similar to the electrode 20 described above. The resistivity measuring device 60 has multiple electrical wires 65 extending from each electrode support 64, and passes an alternating current through the electrical wires 65 to two of the four electrodes 61. The resistivity measuring device 60 then measures the resistivity of the embankment B by measuring the potential difference between the remaining two electrodes 61. Thus, the embankment evaluation system equipped with the resistivity measuring device 60 can obtain the same effects as the embankment evaluation system 1 described above.
[0083] The embankment evaluation system described herein is not limited to the modified embankment evaluation system and can be further modified. In the above-described embodiment, an embankment evaluation system 1 was described in which the embankment evaluation item calculation unit 32 calculates at least one of the dry density of embankment B and the water content of embankment B from the air porosity of embankment B calculated by the air porosity calculation unit 31 and the volumetric water content of embankment B measured by the volumetric water content measuring device 15. However, the embankment evaluation system may directly calculate at least one of the dry density and water content from the resistivity and moisture meter measurement results. That is, the dry density or water content may be calculated without using air porosity and volumetric water content. For example, the embankment evaluation system may directly calculate at least one of the dry density and water content by combining the resistivity measured by the resistivity measuring device 10 and the count number measured by the scattering type RI moisture meter 16 (the number of thermal neutron beams Z2 (see Figure 5) described above).
[0084] In the embodiment described above, an example was described in which two holders 41 are connected to each other via a linear body 48, as shown in Figure 2. For example, this linear body 48 may have a sheath tube structure that can change its length by expanding and contracting. In this case, the distance X between the potential electrode 21 and the current electrode 22 can be easily changed while the linear body 48 is attached. The linear body 48 having a sheath tube structure may expand and contract by remote control operation. Furthermore, the linear body 48 having a sheath tube structure may expand and contract automatically. In this case, the adjustment of the distance X can be made even easier.
[0085] For example, in the embodiment described above, an example was described in which the second linear body 3 extends from the resistivity measuring device 10, as shown in Figure 1. However, the second linear body may extend from the volumetric moisture content measuring device 15. In this case, the volumetric moisture content measuring device 15 will be located in front of the resistivity measuring device 10, but the same effects and advantages as in the embodiment described above can be obtained.
[0086] In the embodiments described above, a resistivity measuring device 10 and a volumetric moisture content measuring device 15 were described as being towed on the ground S. However, the resistivity measuring device and the volumetric moisture content measuring device may travel on the ground S by remote control operation. The resistivity measuring device and the volumetric moisture content measuring device may be equipped with a crawler-type running section (e.g., tracks). Furthermore, the resistivity measuring device and the volumetric moisture content measuring device may travel automatically on the ground S.
[0087] The embankment evaluation system described in this disclosure applies to soil, and specifically includes, but is not limited to, sand and gravel obtained at construction sites in the CSG (Cemented Sand and Gravel) method, which is mixed with cement;, in the RCD (Roller Compacted Dam-Concrete) method, which is laid down and compacted with a vibratory roller or the like using ultra-hard concrete with a reduced amount of cement; and, in addition, the cover soil for radioactive disposal projects. [Explanation of symbols]
[0088] 1…Embankment evaluation system, 2…First linear body, 3…Second linear body, 10…Resistivity measuring device, 15…Volumetric water content measuring device, 16…Scattering type RI moisture meter, 16b…Neutron source, 16c…Thermal neutron detection unit, 16d…Housing, 17…Traveling body, 17b…Wheels, 17c…Base, 18…Holding part, 20…Electrode, 20b…Top surface, 21…Potential electrode, 2 2...Current electrode, 23...Dielectric, 24...Conductor, 25...AC power supply, 26...Voltmeter, 30...Towing unit, 30b...Wheel, 30c...Base unit, 30d...Handle unit, 31...Air void ratio calculation unit, 32...Embankment evaluation item calculation unit, 41...Holder, 41b...Top surface, 42...Caster, 43...Electrode holder, 43c...Plate-shaped part, 43d...Rod-shaped part, 43f...Electrode holder Attachment part, 43g...hole, 43h...overpass part, 44...handle part, 45...variable mechanism, 45b...slit, 45c...rod-shaped part, 45d...stopper part, 46...spring mechanism, 47...spring, 48...linear body, 50...calibration curve acquisition device, 50b...bottom part, 50c...lid part, 50d...side part, 51...first electrode, 52...second electrode, 53...third electrode, 54...fourth electrode, 60...Resistivity measuring device, 61...Electrode, 62...Axle, 63...Wheel, 64...Electrode support, 65...Electrical wiring, A...Site, B...Embankment, B1...Hydrogen atom, C...Embankment material, D1... 1st direction, D2...2nd direction, D3...3rd direction, J...axial direction, L...calibration curve, ρ...specific resistance, S...ground, X...distance, Y...interval, Z1...fast neutron, Z2...thermal neutron beam.
Claims
1. A resistivity measuring device having a pair of potential electrodes and a pair of current electrodes for measuring the resistivity of an embankment while facing the embankment, A volumetric moisture content measuring device having a scattering-type RI moisture meter for measuring the volumetric moisture content of the embankment while facing the embankment, A soil evaluation item calculation unit calculates at least one of the dry density of the soil and the water content of the soil by combining the resistivity of the soil measured by the resistivity measuring device and the measurement results from the scattering type RI moisture meter, Equipped with, A first linear body connecting the resistivity measuring device and the volumetric water content measuring device, It comprises a second linear body extending from either the resistivity measuring device or the volumetric water content measuring device, The resistivity measuring device and the volumetric water content measuring device are pulled on the embankment by the pulling of the second linear body. Embankment evaluation system.
2. A resistivity measuring device having a pair of potential electrodes and a pair of current electrodes for measuring the resistivity of an embankment while facing the embankment, A volumetric moisture content measuring device having a scattering-type RI moisture meter for measuring the volumetric moisture content of the embankment while facing the embankment, A soil evaluation item calculation unit calculates at least one of the dry density of the soil and the water content of the soil by combining the resistivity of the soil measured by the resistivity measuring device and the measurement results from the scattering type RI moisture meter, Equipped with, The resistivity measuring device, Multiple electrode holding units that hold each of the pair of potential electrodes and the pair of current electrodes facing the embankment, Multiple spring mechanisms are provided corresponding to each of the multiple electrode holding portions, and each electrode holding portion biases toward the embankment side. Having, Embankment evaluation system.
3. The system includes an air void ratio calculation unit that calculates the air void ratio of the embankment from the resistivity of the embankment measured by the resistivity measuring device, The embankment evaluation item calculation unit calculates at least one of the dry density of the embankment and the water content ratio of the embankment from the air porosity of the embankment calculated by the air porosity calculation unit and the volumetric water content of the embankment measured by the volumetric water content measuring device. The embankment evaluation system according to claim 1 or claim 2.
4. The pair of potential electrodes and the pair of current electrodes are capacitor electrodes. The embankment evaluation system according to claim 1 or 2.
5. A step in which a pair of potential electrodes and a pair of current electrodes facing the embankment measure the resistivity of the embankment, A scattering-type RI moisture meter facing the embankment measures the volumetric water content of the embankment. A step of calculating the air porosity of the embankment from the resistivity of the embankment, A step of calculating at least one of the dry density of the embankment and the water content ratio of the embankment from the air void ratio of the embankment and the volumetric water content of the embankment, A step of conducting a compaction test on the embankment before it is constructed, A step of obtaining the relationship between the resistivity and air void ratio of the embankment, Equipped with, The process of performing the compaction test and the process of obtaining the relationship are performed simultaneously. Methods for evaluating embankments.
6. A step in which a pair of potential electrodes and a pair of current electrodes facing the embankment measure the resistivity of the embankment, A scattering-type RI moisture meter facing the embankment measures the volumetric water content of the embankment. A step of calculating the air porosity of the embankment from the resistivity of the embankment, A step of calculating at least one of the dry density of the embankment and the water content ratio of the embankment from the air void ratio of the embankment and the volumetric water content of the embankment, Equipped with, A resistivity measuring apparatus for performing the process of measuring resistivity, Multiple electrode holding units that hold each of the pair of potential electrodes and the pair of current electrodes facing the embankment, Multiple spring mechanisms are provided corresponding to each of the multiple electrode holding portions, and each electrode holding portion biases toward the embankment side. Having, Methods for evaluating embankments.
7. A resistivity measuring device having a pair of potential electrodes and a pair of current electrodes, A volumetric water content measuring device having the aforementioned scattering-type RI moisture meter, Equipped with, The steps of measuring resistivity and measuring volumetric water content are performed while the resistivity measuring device and the volumetric water content measuring device are towed on the embankment. The embankment evaluation method according to claim 5 or claim 6.