Improved soil electrical conductivity prediction system, improved soil quality confirmation system, improved soil electrical conductivity prediction method, and improved soil quality confirmation method

Abstract

To provide a system for predicting the electrical conductivity of improved soil, which can grasp the mixing conditions of improved soil before construction. [Solution] The improved soil electrical conductivity prediction system is an improved soil electrical conductivity prediction system that predicts the electrical conductivity in the depth direction of unhardened improved soil obtained by mixing and stirring a solidification material slurry, which is a mixture of cement-based solidification material and mixing water, into the original ground, and has a slurry electrical conductivity measurement unit that measures the electrical conductivity of the solidification material slurry, an original ground relative dielectric constant measurement unit that measures the relative dielectric constant of the original ground, and a prediction unit that predicts the electrical conductivity of the unhardened improved soil and the variation in the electrical conductivity based on the water to solidification material ratio of the solidification material slurry, the electrical conductivity of the solidification material slurry, and the relative dielectric constant of the original ground.

Description

[Technical Field]

[0001] The present invention relates to a system for predicting the electrical conductivity of improved soil, a system for confirming the quality of improved soil, a method for predicting the electrical conductivity of improved soil, and a method for confirming the quality of improved soil. [Background technology]

[0002] A known method for improving soft ground is the mechanical mixing treatment method, in which a cement-based solidification material is mixed into the original ground and stirred. With this method, the number of times the blades are cut is specified as a construction management item to ensure the degree of mixing during construction. This is because increasing the number of times the blades are cut reduces the variation in the unconfined compressive strength after solidification, which is an indicator of the quality of the solidified improved ground. However, when controlling the number of times the blades are cut during construction, it is necessary to wait for the results of strength tests on the improved soil after solidification, and it is not possible to check the results during construction.

[0003] Furthermore, Non-Patent Document 1 discloses a method for checking the degree of mixing during construction by measuring the difference in electrical conductivity between the target soil and the unhardened, solidified and improved ground, taking advantage of the fact that the variation in electrical conductivity in unhardened, solidified and improved ground decreases as the number of blade cuts increases. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] J.Struct.Censtr.Eng.,AIJ,No.531,95-99,May,2000 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology that uses the electrical conductivity of unhardened solidified improved ground confirms the relative difference in electrical conductivity with the target soil, not the absolute value of electrical conductivity, and therefore it is not possible to fully understand the mix conditions, such as the degree of mixing and stirring.In addition, since it is necessary to measure the electrical conductivity of unhardened solidified improved ground, it is not possible to understand the mix conditions before construction.

[0006] An object of the present invention is to provide a system for predicting the electrical conductivity of improved soil that can grasp the mix conditions of improved soil before construction. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the electrical conductivity prediction system of improved soil according to the present disclosure is a system for predicting the electrical conductivity of improved soil in a depth direction of unhardened improved soil obtained by mixing and stirring a solidification material slurry, which is a mixture of a cement-based solidification material and mixing water, with the original ground. In multiple locations A system for predicting the electrical conductivity of improved soil, comprising: a slurry electrical conductivity measuring unit for measuring the electrical conductivity of the solidification material slurry; At a plurality of positions corresponding to the depth direction A ground dielectric constant measuring unit for measuring the dielectric constant of the original ground, and a measuring unit for measuring the electrical conductivity and at a plurality of positions in the depth direction The variation in the electrical conductivity is calculated based on the water-solidification material ratio of the solidification material slurry, the electrical conductivity of the solidification material slurry, and the at a plurality of positions in the depth direction and a prediction unit that makes a prediction based on the relative dielectric constant. [Effects of the Invention]

[0008] According to one aspect of the present invention, it is possible to provide a system for predicting the electrical conductivity of improved soil, which can grasp the mix conditions of improved soil before construction. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 shows an embodiment of a cone test. [Figure 2] FIG. 1 is a diagram illustrating the configuration of a system for predicting the electrical conductivity of improved soil. [Figure 3] FIG. 1 is a schematic diagram showing the mix of improved soil. [Figure 4] 1 is a graph showing the relationship between the water-solidification material ratio and electrical conductivity in the pores of solidification material slurry alone, soil sample, and improved soil. [Figure 5] 1 is a table showing the physical properties of soil samples. [Figure 6] 1 is a table showing the mixing conditions of improved soil. [Figure 7] 1 is a graph showing the relationship between the measured and predicted electrical conductivity values ​​of improved soil. [Figure 8] 1 is a graph showing the relationship between the actual measured value or its variation and the predicted value or its variation in the electrical conductivity of improved soil. [Figure 9] This is a process diagram of a method for predicting the electrical conductivity of improved soil. [Figure 10] This is a process diagram of a method for predicting the electrical conductivity of improved soil. [Figure 11] This is a process diagram of a method for predicting the electrical conductivity of improved soil. [Figure 12] This is a process diagram for measuring the electrical conductivity of improved soil. [Figure 13] This is a process diagram of a method for checking the quality of improved soil. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail.

[0011] <Improved soil electrical conductivity prediction system> The improved soil electrical conductivity prediction system according to the present disclosure predicts the electrical conductivity in the depth direction of unhardened improved soil obtained by mixing and stirring a solidification material slurry into the original ground.

[0012] In this specification, the original ground refers to the natural (original topography) ground before construction that is the target of improvement. The unhardened improved soil refers to a portion of the soil that makes up the original ground that has been improved. The depth direction refers to the direction from the surface of the earth toward the ground.

[0013] The solidification material slurry is a mixture of cement-based solidification material and mixing water. Specifically, the cement-based solidification material and mixing water to be used, and the mass ratio between them, that is, the water-solidification material ratio, are set. The cement-based solidification material refers to a powder whose main ingredients are limestone, clay, silica, iron oxide raw material, etc., which hardens through a chemical reaction with water. In this disclosure, blast furnace cement type B is used as the cement-based solidification material.

[0014] Electrical conductivity is a numerical value that indicates the ease with which electricity passes through a material, and its unit is S / m. The electrical conductivity of the original ground and unhardened improved soil in the depth direction can be measured using a tester (cone penetration tester) that can penetrate a cone into a model ground using a cone test, as shown in Figure 1. The cone penetration tester may be configured to measure not only electrical conductivity but also the relative permittivity.

[0015] In Figure 1, a cone penetration tester 3 is inserted into a model ground 2 (kaolin clay with a moisture content of 69%), which is a simulation of the original ground, and filled into a polyvinyl chloride pipe 1 to a depth of L1, to measure the electrical conductivity of the model ground 2. At this time, the tip of the penetration tester 3, which has a length of L2, is inserted from the top to the bottom of the pipe 1 (see Figure 1(i)).

[0016] Next, the solidification material slurry 5 contained in the container 4 is poured from the top end into the pipe 1 filled with the model ground 2, and stirred and mixed with a mixer 6 (see Figure 1 (ii)). As a result, unhardened improved soil 7 is obtained within the range of depth L3 (see Figure 1 (ii)). The electrical conductivity and relative permittivity of the solidification material slurry 5 are measured in advance. In this disclosure, blast furnace cement type B is used for the solidification material slurry 5.

[0017] The cone penetration tester 3 is inserted in the depth direction of the improved soil 7 and the model ground 2 to measure the electrical conductivity of the improved soil 7 and the model ground 2 (see Figure 1 (iii)).

[0018] As shown in FIG. 2, the electrical conductivity prediction system 100 of the present disclosure includes a slurry electrical conductivity measurement unit 30, an original ground relative dielectric constant measurement unit 50, and a prediction unit 70, and optionally includes a control unit 10, a memory unit 20, a slurry relative dielectric constant measurement unit 40, a volumetric water content calculation unit 60, and a display unit (not shown).

[0019] The control unit 10 is configured, for example, by a computer having a central processing unit (CPU), and performs various processes such as calculation, storage, transfer, input, output, etc. The CPU may be configured separately from the control unit 10.

[0020] The manner in which the control unit 10 is disposed is not particularly limited, and the control unit 10 can be disposed within the electrical conductivity prediction system 100. Alternatively, the control unit 10 may be disposed at a location remote from the electrical conductivity prediction system 100 and communicably connected to the electrical conductivity prediction system 100 via a wired or wireless connection. Furthermore, the control unit 10 may be controlled using an application installed on an external device such as a smartphone or tablet terminal.

[0021] The storage unit 20 constitutes a temporary storage device that stores information calculated when the CPU executes processing under the control of the control unit 10. The storage unit 20 may be provided within the control unit 10.

[0022] The storage unit 20 may also be configured separately from the electrical conductivity prediction system 100. In this case, the electrical conductivity prediction system 100 may be provided with an auxiliary device (not shown) such as a hard disk drive (HDD) capable of wired or wireless communication and a modular jack to which the HDD can be connected, outside the system.

[0023] The slurry electrical conductivity measuring unit 30 measures the electrical conductivity of the solidification material slurry. In the slurry electrical conductivity measuring unit 30 of the present disclosure, the electrical conductivity of the solidification material slurry before being mixed with the original ground is measured under the control of the control unit 10, and the measured electrical conductivity of the solidification material slurry is stored in the memory unit 20.

[0024] The slurry relative permittivity measuring unit 40 measures the relative permittivity of the solidification material slurry. In the slurry relative permittivity measuring unit 40 of the present disclosure, the relative permittivity of the solidification material slurry before being mixed with the original ground is measured under the control of the control unit 10, and the measured relative permittivity of the solidification material slurry is stored in the memory unit 20. Note that the measurement of the relative permittivity of the solidification material slurry may be performed simultaneously with the measurement of the electrical conductivity of the solidification material slurry (see FIG. 1(ii)).

[0025] The slurry relative permittivity measuring unit 40 calculates a corrected value by correcting the electrical conductivity of the solidification material slurry based on the relative permittivity of the solidification material slurry. The slurry relative permittivity measuring unit 40 of the present disclosure calculates a corrected value by correcting the electrical conductivity of the solidification material slurry measured by the slurry electrical conductivity measuring unit 30 based on the relative permittivity of the solidification material slurry measured by the slurry relative permittivity measuring unit 40.

[0026] The original ground relative permittivity measuring unit 50 measures the relative permittivity of the original ground. In the original ground relative permittivity measuring unit 50 of the present disclosure, the relative permittivity of the original ground before mixing with the solidification material slurry is measured under the control of the control unit 10, and the measured relative permittivity of the original ground is stored in the memory unit 20.

[0027] The volumetric water content calculation unit 60 calculates the volumetric water content of the original ground from the relative dielectric constant. In the volumetric water content calculation unit 60 of the present disclosure, the volumetric water content of the original ground is calculated based on the relative dielectric constant of the original ground measured by the original ground relative dielectric constant measurement unit 50 under the control of the control unit 10.

[0028] The prediction unit 70 predicts the electrical conductivity and the variation in electrical conductivity of the unhardened improved soil based on the water-to-solidification material ratio of the solidification material slurry, the electrical conductivity of the solidification material slurry, and the relative dielectric constant of the original ground.

[0029] In the prediction unit 70 of the present disclosure, under the control of the control unit 10, a predicted value of the electrical conductivity of the improved soil in an unhardened state and a predicted value of the variation range of the electrical conductivity are estimated from the water-to-solidification material ratio of the solidification material slurry, the relative dielectric constant of the original ground measured by the slurry electrical conductivity measuring unit 30, and the relative dielectric constant of the original ground measured by the original ground relative dielectric constant measuring unit 50, and the estimated predicted value of the electrical conductivity and the predicted value of the variation range of the electrical conductivity are stored in the memory unit 20.

[0030] Furthermore, it is preferable that the prediction unit 70 predicts the electrical conductivity and the variation in electrical conductivity of the unhardened improved soil based on the volumetric water content of the original ground. The prediction unit 70 of the present disclosure estimates the predicted value of the electrical conductivity and the predicted value of the variation in electrical conductivity of the unhardened improved soil from the water-to-solidification material ratio of the solidification material slurry, the slurry electrical conductivity measured by the slurry electrical conductivity measuring unit 30, and the volumetric water content of the original ground calculated by the volumetric water content calculating unit 60.

[0031] The display unit is optionally provided and, under the control of the control unit 10, displays the measured electrical conductivity of the solidification material slurry, the measured relative permittivity of the solidification material slurry, the measured relative permittivity of the original ground, the estimated predicted value of the electrical conductivity, the predicted value of the variation range of the electrical conductivity, etc. The form of the display unit is not particularly limited and may be, for example, a display. The location of the display unit is not particularly limited and may be, for example, a monitor or a display of a tablet terminal connected to the electrical conductivity prediction system 100 so as to be able to communicate with it via wire or wirelessly.

[0032] In the electrical conductivity prediction system 100 of the present disclosure, the predicted value of the electrical conductivity of the unhardened improved soil and the predicted value of the variation width of the electrical conductivity are estimated using the following formulas (1) to (8).

[0033] First, in deriving the following equation, we use the volume and mass of the original ground (soil sample) per unit volume, as shown schematically in Figure 3. Rhoades et al. [Rhoades, JD, Raats, PAC, and Prather, RJ: Effects of Liquid-Phase Electrical Conductivity, Water Content, and Surface Conductivity on Bulk-Soil Electrical Conductivity, Soil Science Society of America Journal, 40, pp.651-655, 1976.] assume that the electrical resistance of the soil is formed by a parallel relationship between the electrical resistance of the liquid phase and the solid surface of the soil. The apparent electrical conductivity, which is the reciprocal of this, is shown in equation (1) below. Note that a and b are empirical constants, a = 1.2867 and b = -0.1158, and the surface electrical conductivity of the soil particles is χ S =0.025S / m.

[0034]

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[0035] The volumetric water content θ is estimated using the relative dielectric constant by Topp's equation shown in the following equation (2) [Topp, GC, Davis, JL and Annan, AP: Electromagnetic Determination of Soil Water Content: Measurement in Coaxial Transmission Lines, Water Resources Research, 16 (3), 574-582, 1980.]. The calculation of the volumetric water content θ from the relative dielectric constant using the following equation (2) is performed by the volumetric water content calculation unit 60 of the present disclosure.

[0036]

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[0037] To obtain the apparent electrical conductivity using the above formula (1), the electrical conductivity of the pore water is required. The electrical conductivity of an aqueous solution is expressed as the sum of the product of the molar conductivity of ion i and the ion concentration, as shown in the following formula (3).

[0038]

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[0039] It is difficult to accurately quantify the individual ion concentrations and molar conductivity shown in the above formula (3). Here, the cement concentration is defined as the mass of cement-based solidification material relative to the volume of the slurry, as shown in the following formula (4), and is used as a substitute for the total ion concentration.

[0040]

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[0041] Figure 4 shows the relationship between the cement concentration and electrical conductivity in the pores of the solidification material slurry alone, the soil samples, and the improved soil. In Figure 4, the soil samples used were soil samples 1 to 4 shown in Figure 5, the improved soil samples were soil samples 1 to 20 shown in Figure 6, and tap water was used.

[0042] The electrical conductivity of the solidification material slurry alone is 3 The increase is linear up to 429 kg / m. 3 From this relationship, as an example, when the cement concentration is 160 kg / m, which is the intersection of the approximate lines, as shown in Figure 4, 3 The electrical conductivity of the solidification slurry is assumed to be a bilinear relationship with an inflection point at . That is, when the cement concentration is 160 kg / m 3 It is assumed that the total molar conductivity in equation (3) above is constant and increases linearly with cement concentration up to this point, and remains constant above this concentration.

[0043] Based on this bilinear assumption, the electrical conductivity in the improved soil pores is estimated using the following formula (5). The cement concentration in formula (5) is calculated using the following formula (6), and the solidification material slurry volume in formula (6) is calculated using the following formula (7). Note that the θ g is the value of the soil sample, and in the following equation (7), ρ c =3.04Mg / m 3 , ρ w =1.00Mg / m 3 In this case, the predicted values ​​of electrical conductivity relative to cement concentration in the improved soil pores using the following formula (5) are shown in Figure 4.

[0044]

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[0045]

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[0046]

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[0047]

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[0048] Using the electrical conductivity of the pore water in the improved soil obtained by the above formula (5), the apparent electrical conductivity of the improved soil is estimated by the above formula (1). Note that θ in the above formula (1) is θ c Let θ c is obtained by the above formula (8). c The volumetric water content of the improved soil is estimated from the above equations (1), (5) to (8). The calculation of the volumetric water content θ from the relative dielectric constant using the equations (1), (5) to (8) is performed by the volumetric water content calculation unit 60 of the present disclosure.

[0049] Figure 7 shows the relationship between the measured and predicted electrical conductivity of improved soil. When comparing the predicted electrical conductivity of unhardened improved soil estimated using the above formulas (1) to (8) with the measured values ​​shown in Figure 1, it can be seen that the predicted values ​​are consistent with the measured values ​​and generally reproduce the measured values. Furthermore, Figure 7 shows that accurate predicted values ​​can be obtained even when the mixing water is seawater.

[0050] Figure 8 shows the relationship between the measured electrical conductivity of improved soil, its variability, and the predicted electrical conductivity, its variability. Figure 8 shows a continuous prediction of the electrical conductivity of the solidification material slurry mixing and stirring layer in the depth direction. As shown in comparison with Figure 8, the maximum predicted electrical conductivity value and depth generally match the measured values, so the predicted value and the degree of mixing and stirring can be assumed to be generally appropriate. However, the gradient of electrical conductivity increase in the depth direction differs. In Figure 8, the solidification material slurry is introduced from the surface and mixed and stirred in the depth direction, so it can be assumed that there is relatively more solidification material slurry near the surface, resulting in a larger measured value. In other words, since the "mixing" in the degree of mixing and stirring refers to the amount of solidification material slurry mixed, and the "stirring" refers to the homogeneity of the mixed layer, this disclosure allows for quantitative evaluation from both the mixing and stirring perspectives.

[0051] As described above, the improved soil electrical conductivity prediction system 100 according to the present disclosure estimates the electrical conductivity and electrical conductivity variation of unhardened improved soil based on the water-to-solidification agent ratio of the solidification agent slurry, the electrical conductivity of the solidification agent slurry, and the relative permittivity of the original ground. This allows the mix conditions of the improved soil to be understood before construction.

[0052] The electrical conductivity prediction system 100 of the present disclosure further predicts the electrical conductivity and electrical conductivity variation of the unhardened improved soil based on the volumetric water content of the original ground calculated from the dielectric constant, thereby making it possible to accurately grasp the mix conditions of the improved soil before construction.

[0053] Furthermore, in the electrical conductivity prediction system 100 of the present disclosure, the corrected value obtained by correcting the electrical conductivity of the solidification material slurry based on the relative dielectric constant of the solidification material slurry is calculated using the following equations (9) and (10).

[0054] The electrical conductivity of the pore water is estimated as a correction value using the Hilhorst equation shown in the following equation (9) [Hilhorst, MA: A Pore Water Conductivity Sensor, Soil Science Society of America Journal, 64 (6), pp.1922-1925, 2000.]. Furthermore, the relative permittivity of the pore water is calculated using the following equation (10) based on the relative permittivity of pure water at 20°C (80.3).

[0055]

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[0056]

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[0057] The calculated correction value indicates the electrical conductivity of the pore water. By using this correction value, in which the electrical conductivity of the solidification material slurry is corrected based on the relative permittivity of the solidification material slurry, it is possible to more accurately grasp the mix conditions of the improved soil before construction.

[0058] <Quality confirmation system> The quality confirmation system of the present disclosure has a quality determination unit 80. The quality determination unit 80 compares the predicted value of the electrical conductivity and / or the predicted value of the variation in electrical conductivity of the improved soil in an unhardened state, predicted by the electrical conductivity prediction system for improved soil according to the present disclosure, with the actual measured value of the electrical conductivity and / or the actual measured value of the variation in electrical conductivity of the improved soil in an unhardened state, to determine the quality of the improved soil.

[0059] The quality determination unit 80 can be configured as a part of the electrical conductivity prediction system 100 described above, as shown in FIG.

[0060] The quality determination unit 80, under the control of the control unit 10, compares the predicted value of electrical conductivity with the actually measured value of electrical conductivity. Also, under the control of the control unit 10, the quality determination unit 80 compares the predicted variation range of electrical conductivity with the actually measured variation range of electrical conductivity. Then, under the control of the control unit 10, the quality determination unit 80 determines the quality of the improved soil from the comparison result. The comparison result and the determined quality result are stored in the memory unit 20 under the control of the control unit 10.

[0061] The quality of the improved soil that can be judged by the quality judging unit 80 is, for example, the degree of mixing and stirring when the solidification material slurry is mixed and stirred with the original ground, the amount of cement-based solidification material mixed, and the like.

[0062] The quality assessment unit 80 inputs the relative permittivity of the original ground measured in the depth direction, the electrical conductivity of the solidification slurry to be mixed, etc., and displays the predicted electrical conductivity value in the depth direction of the improved ground in an unhardened state. Upper and lower limits of the predicted value (predicted range of variation) can also be input and set. In addition, the actual measured value in the depth direction measured after mixing and stirring is displayed, and compared with the predicted value and range of variation, and a judgment is made as to whether the mixing or stirring was good or bad at all depths or at specific depths. If the judgment is bad, remixing and remixing can be carried out immediately on site.

[0063] The quality confirmation system of the present disclosure further includes an original ground electrical conductivity measurement unit 90. The original ground electrical conductivity measurement unit 90 measures the electrical conductivity of the original ground. The original ground electrical conductivity measurement unit 90 of the present disclosure can be configured as part of the above-mentioned electrical conductivity prediction system 100, as shown in FIG. 2.

[0064] In the original ground electrical conductivity measuring unit 90 of the present disclosure, the electrical conductivity of the original ground before mixing with the solidification material slurry is measured under the control of the control unit 10, and the measured electrical conductivity of the original ground is stored in the memory unit 20.

[0065] In the quality confirmation system of the present disclosure, the quality determination unit 80 further compares the predicted value of the electrical conductivity and / or the predicted value of the electrical conductivity variation of the unhardened improved soil with the actual measured value of the electrical conductivity of the original ground and the actual measured value of the relative dielectric constant and / or the actual measured value of the electrical conductivity variation of the original ground. Then, the quality determination unit 80 determines the quality of the improved soil based on the comparison results under the control of the control unit 10. The comparison results and the determined quality results are stored in the memory unit 20 under the control of the control unit 10.

[0066] As described above, the quality confirmation system of the present disclosure compares the predicted electrical conductivity and / or predicted electrical conductivity variation of unhardened improved soil with the actual measured electrical conductivity and / or actual measured electrical conductivity variation of unhardened improved soil to determine the quality of the improved soil. This makes it possible to determine the appropriate mix conditions for the improved soil before construction.

[0067] As described above, in the quality confirmation system of the present disclosure, the quality of the improved soil that can be judged is the degree of mixing and stirring when the solidification material slurry is mixed and stirred into the original ground, so that the appropriate degree of mixing and stirring of the improved soil can be determined before construction.

[0068] In the quality confirmation system of the present disclosure, as described above, the quality of the improved soil that can be judged is the amount of cement-based solidification material mixed, so that the amount of cement-based solidification material mixed can be determined before construction.

[0069] As described above, the quality confirmation system of the present disclosure compares the predicted electrical conductivity and / or the predicted electrical conductivity variation of unhardened improved soil with the actual measured values ​​of the electrical conductivity and relative permittivity and / or the actual measured values ​​of the electrical conductivity variation of the original ground, thereby making it possible to determine more appropriate mix conditions for improved soil before construction.

[0070] <Method for predicting the electrical conductivity of improved soil> 9 to 11 are process diagrams of a method for predicting the electrical conductivity of improved soil. The method for predicting the electrical conductivity of improved soil according to the present disclosure is a method for predicting the electrical conductivity in the depth direction of improved soil in an unhardened state obtained by mixing and stirring a solidification material slurry, which is a mixture of a cement-based solidification material and mixing water, with the original ground. The method for predicting the electrical conductivity of improved soil according to the present disclosure can be executed by the electrical conductivity prediction system 100 described above.

[0071] The method for predicting the electrical conductivity of improved soil according to the present disclosure includes a step of measuring the electrical conductivity of a solidification material slurry. In the method for predicting electrical conductivity according to the present disclosure, the relative permittivity and electrical conductivity of the solidification material slurry whose water-to-solidification material ratio has been specified are measured (step S1), as shown in Fig. 9. The step of measuring the electrical conductivity of the solidification material slurry according to the present disclosure can be performed by the slurry electrical conductivity measuring unit 30.

[0072] The method for predicting the electrical conductivity of improved soil according to the present disclosure includes a step of measuring the dielectric constant and electrical conductivity of the original ground. The step of measuring the dielectric constant and electrical conductivity of the original ground according to the present disclosure measures the dielectric constant and electrical conductivity of the original ground (step S2), as shown in Fig. 10. The step of measuring the dielectric constant and electrical conductivity of the original ground according to the present disclosure can be performed by the original ground dielectric constant measuring unit 50 and the original ground electrical conductivity measuring unit 90 described above.

[0073] The method for predicting the electrical conductivity of improved soil according to the present disclosure includes a step of calculating the volumetric water content of the original ground from the relative dielectric constant. As shown in Fig. 10, the step of calculating the volumetric water content of the original ground from the relative dielectric constant according to the present disclosure calculates the volumetric water content of the original ground from the relative dielectric constant measured in step S2 (step S3). The step of calculating the volumetric water content according to the present disclosure can be performed by the volumetric water content calculation unit 60 described above.

[0074] The method for predicting the electrical conductivity of improved soil according to the present disclosure includes a step of predicting the electrical conductivity and electrical conductivity variation of unhardened improved soil based on the water-to-solidification agent ratio of the solidification agent slurry, the electrical conductivity of the solidification agent slurry, and the volumetric water content of the original ground. The step of predicting the electrical conductivity and the electrical conductivity variation width according to the present disclosure predicts the electrical conductivity and the electrical conductivity variation width in the depth direction of the unhardened solidified-improved ground based on the volumetric water content of the original ground, the electrical conductivity of the solidification agent slurry, and the water-to-solidification agent ratio of the solidification agent slurry (step S4), as shown in FIG. 11. The prediction step according to the present disclosure can be performed by the prediction unit 70.

[0075] As described above, the method for predicting the electrical conductivity of improved soil according to the present disclosure includes a step of making a prediction based on the water-to-solidification material ratio of the solidification material slurry, the electrical conductivity of the solidification material slurry, and the volumetric water content of the original ground. This provides the same effects as the above-mentioned system for predicting the electrical conductivity of improved soil 100. In other words, the method for predicting the electrical conductivity of improved soil according to the present disclosure makes it possible to grasp the mix conditions of the improved soil before construction.

[0076] <How to check the quality of improved soil> Fig. 12 is a process diagram for measuring the electrical conductivity of improved soil, and Fig. 13 is a process diagram for a method for confirming the quality of improved soil. The method for confirming the quality of improved soil according to the present disclosure includes a step of comparing the predicted value of the electrical conductivity of improved soil in an unhardened state, predicted by the method for predicting the electrical conductivity of improved soil according to the present disclosure, with the actually measured value of the electrical conductivity of improved soil in an unhardened state, to determine the quality of the improved soil.

[0077] In addition, the quality confirmation method for improved soil according to the present disclosure includes a step of determining the quality of the improved soil by comparing the predicted value of the variation in electrical conductivity of the improved soil in an unhardened state, predicted by the method for predicting the electrical conductivity of improved soil according to the present disclosure, with the actual measured value of the variation in electrical conductivity of the improved soil in an unhardened state.

[0078] The actual measured values ​​to be compared with the predicted values ​​in this disclosure are obtained, for example, as shown in Figure 12, by first formulating a construction plan (step S5), and then measuring the electrical conductivity and the range of variation in electrical conductivity of the unhardened, solidified and improved ground that has been mixed and stirred based on the formulated construction plan (Figure 12, step S6).

[0079] In the process of determining the quality of improved soil in this disclosure, as shown in Fig. 13, first, the predicted value of electrical conductivity is compared with the actually measured value of electrical conductivity, and / or the predicted variation range of electrical conductivity is compared with the actually measured variation range of electrical conductivity (step S7). Next, it is determined whether the predicted value of electrical conductivity or the predicted variation range of electrical conductivity is within the range of the actually measured variation range of electrical conductivity (step S8).

[0080] If the determination in step S8 is No, proceed to step S5 and modify the construction plan (step S5). If the determination in step S8 is Yes, the implementation of the improved soil quality confirmation method is terminated. The process of determining the quality of improved soil according to the present disclosure can be performed by the above-mentioned quality confirmation system (quality determination unit 80 of the electrical conductivity prediction system 100).

[0081] As described above, the improved soil quality confirmation method according to the present disclosure includes a step of comparing the predicted value of the electrical conductivity of the unhardened improved soil, predicted by the improved soil electrical conductivity prediction method, with the actually measured value of the electrical conductivity of the unhardened improved soil, to determine the quality of the improved soil. This provides the same effect as the improved soil quality confirmation system (quality determination unit 80 of the electrical conductivity prediction system 100) described above. In other words, the improved soil quality confirmation method according to the present disclosure makes it possible to determine the appropriate mix conditions for the improved soil before construction.

[0082] The improved soil quality confirmation method according to the present disclosure includes a step of comparing the predicted value of the variation in the electrical conductivity of the unhardened improved soil, predicted by the improved soil electrical conductivity prediction method, with the actually measured value of the variation in the electrical conductivity of the unhardened improved soil, to determine the quality of the improved soil. This provides the same effect as the improved soil quality confirmation system (quality determination unit 80 of the electrical conductivity prediction system 100) described above. In other words, the improved soil quality confirmation method according to the present disclosure makes it possible to determine more appropriate mix conditions for the improved soil before construction.

[0083] The above-disclosed embodiments include, for example, the following aspects.

[0084] <1> A system for predicting the electrical conductivity of improved soil that predicts the electrical conductivity in the depth direction of unhardened improved soil obtained by mixing and stirring a solidification material slurry, which is a mixture of a cement-based solidification material and mixing water, into the original ground, a slurry electrical conductivity measuring unit that measures the electrical conductivity of the solidification material slurry; an original ground relative permittivity measuring unit that measures the relative permittivity of the original ground; and a prediction unit that estimates the electrical conductivity and the variation in the electrical conductivity of the unhardened improved soil based on the water-to-solidification material ratio of the solidification material slurry, the electrical conductivity of the solidification material slurry, and the relative dielectric constant of the original ground. A system for predicting the electrical conductivity of improved soil.

[0085] <2> a volumetric water content calculation unit that calculates the volumetric water content of the original ground from the relative dielectric constant, The prediction unit predicts the electrical conductivity and the variation in the electrical conductivity of the improved soil in the unhardened state based on the volumetric water content of the original ground. The aforementioned <1> The electrical conductivity prediction system for improved soil described in the above.

[0086] <3> Further, a slurry relative dielectric constant measuring unit is provided to measure the relative dielectric constant of the solidification material slurry, Calculating a corrected value obtained by correcting the electrical conductivity of the solidification material slurry based on the relative dielectric constant of the solidification material slurry. The aforementioned <1> or <2> The electrical conductivity prediction system for improved soil described in the above.

[0087] <4> The aforementioned <1> ~ <3> and a quality determination unit that determines the quality of the improved soil by comparing the predicted value of the electrical conductivity and / or the predicted value of the variation in the electrical conductivity of the improved soil in an unhardened state, which is predicted by the electrical conductivity prediction system for improved soil described in any one of the above with the actual measured value of the electrical conductivity and / or the actual measured value of the variation in the electrical conductivity of the improved soil in an unhardened state. Quality confirmation system for improved soil.

[0088] <5> The quality of the improved soil is the degree of mixing and stirring when the solidification material slurry is mixed and stirred with the original ground. The aforementioned <4> A quality confirmation system for improved soil described above.

[0089] <6> The quality of the improved soil is the amount of the cement-based solidification material mixed. The aforementioned <4> A quality confirmation system for improved soil described above.

[0090] <7> An original ground electrical conductivity measuring unit that measures the electrical conductivity of the original ground, The prediction unit compares the predicted value of the electrical conductivity and / or the predicted value of the variation in the electrical conductivity of the unhardened improved soil with the actual measured value of the electrical conductivity and / or the actual measured value of the variation in the electrical conductivity of the original ground. The aforementioned <4> ~ <6> A quality confirmation system for improved soil described in any one of the above.

[0091] <8> A method for predicting the electrical conductivity of improved soil in the depth direction of unhardened improved soil obtained by mixing and stirring a solidification material slurry, which is a mixture of a cement-based solidification material and mixing water, into the original ground, comprising: Measuring the electrical conductivity of the solidification material slurry; measuring the relative dielectric constant of the original ground; calculating the volumetric water content of the original ground from the dielectric constant; and predicting the electrical conductivity and the variation in the electrical conductivity of the unhardened improved soil based on the water-to-solidification material ratio of the solidification material slurry, the electrical conductivity of the solidification material slurry, and the volumetric water content of the original ground. A method for predicting the electrical conductivity of improved soil.

[0092] <9> The aforementioned <8> and a step of comparing the predicted value of the electrical conductivity of the unhardened improved soil predicted by the method for predicting the electrical conductivity of improved soil described in the above with the actually measured value of the electrical conductivity of the unhardened improved soil to determine the quality of the improved soil. How to check the quality of improved soil.

[0093] <10> The aforementioned <8> or <9> and a step of comparing the predicted value of the variation in the electrical conductivity of the improved soil in the unhardened state predicted by the method for predicting the electrical conductivity of improved soil described in the above with the actually measured value of the variation in the electrical conductivity of the improved soil in the unhardened state to determine the quality of the improved soil. How to check the quality of improved soil.

[0094] Although the embodiments of the present invention have been described above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the invention described in the claims. [Explanation of symbols]

[0095] 1 pipe 2 Model ground (original ground) 3 Cone Penetration Tester 4 containers 5 Solidification material slurry 6. Mixer 7 Improved soil 10 Control Unit 20 Memory section 30 Slurry electrical conductivity measurement unit 40 Slurry relative permittivity measurement unit 50 Ground dielectric constant measurement section 60 Volumetric moisture content calculation section 70 Prediction Department 80 Quality Judgment Department 90 Ground Electrical Conductivity Measurement Unit 100 Electrical Conductivity Prediction System

Claims

1. A system for predicting the electrical conductivity of improved soil that predicts the electrical conductivity at multiple positions in the depth direction of improved soil in an unhardened state obtained by mixing and stirring a solidification material slurry, which is a mixture of a cement-based solidification material and mixing water, into the original ground, a slurry electrical conductivity measuring unit that measures the electrical conductivity of the solidification material slurry; an original ground relative permittivity measuring unit that measures the relative permittivity at a plurality of positions corresponding to the depth direction of the original ground; and a prediction unit that predicts the electrical conductivity and the variation of the electrical conductivity at a plurality of positions in the depth direction of the unhardened improved soil based on the water-to-solidification material ratio of the solidification material slurry, the electrical conductivity of the solidification material slurry, and the relative dielectric constant at a plurality of positions in the depth direction of the original ground. A system for predicting the electrical conductivity of improved soil.

2. a volumetric water content calculation unit that calculates the volumetric water content of the original ground from the relative dielectric constant, The prediction unit predicts the electrical conductivity and the variation in the electrical conductivity of the improved soil in the unhardened state based on the volumetric water content of the original ground. The system for predicting the electrical conductivity of improved soil according to claim 1.

3. Further, a slurry relative dielectric constant measuring unit is provided to measure the relative dielectric constant of the solidification material slurry, Calculating a corrected value obtained by correcting the electrical conductivity of the solidification material slurry based on the relative dielectric constant of the solidification material slurry. The system for predicting the electrical conductivity of improved soil according to claim 1.

4. a quality determination unit that compares the predicted value of the electrical conductivity and / or the predicted value of the variation in the electrical conductivity of the unhardened improved soil predicted by the electrical conductivity prediction system for improved soil according to any one of claims 1 to 3 with the actual measured value of the electrical conductivity and / or the actual measured value of the variation in the electrical conductivity of the unhardened improved soil to determine the quality of the improved soil; Quality confirmation system for improved soil.

5. The quality of the improved soil is the degree of mixing and stirring when the solidification material slurry is mixed and stirred with the original ground. A quality confirmation system for improved soil according to claim 4.

6. The quality of the improved soil is determined by the suitability of the mixing conditions of the cement-based solidification material. A quality confirmation system for improved soil according to claim 4.

7. An original ground electrical conductivity measuring unit that measures electrical conductivity at a plurality of positions corresponding to the depth direction of the original ground, The quality determination unit compares the predicted value of the electrical conductivity and / or the predicted value of the variation in the electrical conductivity of the unhardened improved soil with the actual measured value of the electrical conductivity of the original ground and the actual measured value of the relative dielectric constant and / or the actual measured value of the variation in the electrical conductivity of the original ground. A quality confirmation system for improved soil according to claim 4.

8. A method for predicting the electrical conductivity of improved soil at a plurality of positions in the depth direction of unhardened improved soil obtained by mixing and stirring a solidification material slurry, which is a mixture of a cement-based solidification material and mixing water, into the original ground, comprising: Measuring the electrical conductivity of the solidification material slurry; measuring the relative dielectric constant at a plurality of positions corresponding to the depth direction of the original ground; calculating the volumetric water content of the original ground from the dielectric constant; and predicting the electrical conductivity and the variation of the electrical conductivity at a plurality of positions in the depth direction of the unhardened improved soil based on the water-to-solidification material ratio of the solidification material slurry, the electrical conductivity of the solidification material slurry, and the volumetric water content at a plurality of positions in the depth direction of the original ground. A method for predicting the electrical conductivity of improved soil.

9. The method for predicting the electrical conductivity of improved soil according to claim 8 includes a step of comparing the predicted value of the electrical conductivity of the unhardened improved soil with the actually measured value of the electrical conductivity of the unhardened improved soil to determine the quality of the improved soil. How to check the quality of improved soil.

10. The method includes a step of comparing the predicted value of the variation in the electrical conductivity of the improved soil in the unhardened state, which is predicted by the method for predicting the electrical conductivity of improved soil according to claim 8, with the actually measured value of the variation in the electrical conductivity of the improved soil in the unhardened state, to determine the quality of the improved soil. How to check the quality of improved soil.

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