Electrical conductivity prediction system for improved soil, quality confirmation system for improved soil, method for predicting electrical conductivity of improved soil, and method for confirming the quality of improved soil.

Abstract

This system provides an electrical conductivity prediction system for improved soil that allows for the determination of the soil mix conditions before construction. [Solution] The improved soil electrical conductivity prediction system predicts the electrical conductivity in the depth direction of unhardened improved soil obtained by mixing and stirring a solidifying agent slurry, which is a mixture of cement-based solidifying agent and mixing water, with the original ground, and comprises a slurry electrical conductivity measurement unit for measuring the electrical conductivity of the solidifying agent slurry, an original ground relative permittivity measurement unit for measuring the relative permittivity of the original ground, and a prediction unit for predicting the electrical conductivity of the unhardened improved soil and the variation in the electrical conductivity based on the water-solidifying agent ratio of the solidifying agent slurry, the electrical conductivity of the solidifying agent slurry, and the relative permittivity 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 method, which involves mixing cement-based solidifying agents into the original ground and stirring it. In this method, the number of blade cuts is specified as a construction management item to ensure the degree of mixing during construction. This utilizes the fact that increasing the number of blade cuts reduces the variation in the uniaxial compressive strength after solidification, which is an indicator for confirming the quality of the solidified improved ground. However, with blade cut count management during construction, it is necessary to wait for the results of strength tests on the improved soil after solidification, and confirmation during construction is not possible.

[0003] Furthermore, Non-Patent Document 1 discloses a method for confirming the degree of mixing during construction by utilizing the fact that increasing the number of blade cutting cycles reduces the variation in electrical conductivity in the unhardened solidified improved ground, and by measuring the difference in electrical conductivity between the target soil and the unhardened solidified improved ground. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] J.Struct.Censtr.Eng.,AIJ,No.531,95-99,May,2000 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, the technology using the electrical conductivity of the solidified improved ground in an uncured state only confirms the relative value of the difference in electrical conductivity from the target soil, and does not confirm the absolute value of the electrical conductivity, so it is not possible to sufficiently grasp the mixing conditions such as the degree of mixing and stirring. In addition, the electrical conductivity of the uncured solidified improved ground must be measured, making it impossible to grasp the mixing conditions before construction.

[0006] An object of the present invention is to provide an electrical conductivity prediction system for improved soil that allows the mixing conditions of the improved soil to be grasped before construction. [Means for Solving the Problems]

[0007] To solve the above-described problems, the electrical conductivity prediction system for improved soil according to the present disclosure predicts the electrical conductivity in the depth direction of uncured improved soil obtained by mixing and stirring a solidification material slurry, which is a mixture of a cement-based solidification material and kneading water, into the original ground. The system includes a slurry electrical conductivity measurement unit that measures the electrical conductivity of the solidification material slurry, an original ground relative permittivity measurement unit that measures the relative permittivity of the original ground, and a prediction unit that predicts the electrical conductivity of the uncured improved soil and the variation in the electrical conductivity based on the water-solidification material ratio of the solidification material slurry, the electrical conductivity of the solidification material slurry, and the relative permittivity of the original ground. [Effects of the Invention]

[0008] According to one aspect of the present invention, it is possible to provide an electrical conductivity prediction system for improved soil that allows the mixing conditions of the improved soil to be grasped before construction. [Brief Description of the Drawings]

[0009] [Figure 1] It is a diagram showing an embodiment of a cone test. [Figure 2] It is a configuration diagram of the electrical conductivity prediction system for improved soil. [Figure 3] It is a schematic diagram showing the mixing of improved soil. [Figure 4]This graph shows the relationship between the water-solidifying agent ratio and electrical conductivity in solidifying agent slurry alone, soil samples, and pores in improved soil. [Figure 5] This is a table showing the physical properties of soil samples. [Figure 6] This is a table showing the mixing conditions for improved soil. [Figure 7] This graph shows the relationship between measured and predicted values ​​for the electrical conductivity of improved soil. [Figure 8] This graph shows the relationship between measured values ​​or their variability and predicted values ​​or their variability in the electrical conductivity of improved soil. [Figure 9] This is a process diagram for predicting the electrical conductivity of improved soil. [Figure 10] This is a process diagram for predicting the electrical conductivity of improved soil. [Figure 11] This is a process diagram for predicting the electrical conductivity of improved soil. [Figure 12] This is a diagram illustrating the process for measuring the electrical conductivity of improved soil. [Figure 13] This is a process diagram for the method of confirming the quality of improved soil. [Modes for carrying out the invention]

[0010] The embodiments of the present invention will be described in detail below.

[0011] <System for predicting the electrical conductivity of improved soil> The improved soil electrical conductivity prediction system described herein predicts the electrical conductivity in the depth direction of unhardened improved soil obtained by mixing and stirring a solidifying agent slurry with the original ground.

[0012] In this specification, "original ground" refers to the natural (original topography) ground before construction that is subject to improvement. "Unhardened improved soil" refers to soil that has been partially improved from the original ground. "Depth direction" refers to the direction from the surface towards the ground.

[0013] Furthermore, the solidification slurry is a mixture of cement-based solidification agent and mixing water. Specifically, the cement-based solidification agent and mixing water used, and the water-solidification agent ratio (the mass ratio between them) are specified. The cement-based solidification agent is a powder that hardens through a chemical reaction with water, mainly composed of limestone, clay, silica, iron oxide raw materials, etc. In this disclosure, blast furnace cement type B is used as the cement-based solidification agent.

[0014] Electrical conductivity is a numerical value that represents how easily electricity passes through a material, and its unit is expressed in S / m. The electrical conductivity in the depth direction of the original ground and unhardened improved soil can be measured, for example, using a 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 also be set up to measure dielectric constant in addition to electrical conductivity.

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

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

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

[0018] As shown in Figure 2, the electrical conductivity prediction system 100 of this disclosure includes a slurry electrical conductivity measurement unit 30, a ground relative permittivity measurement unit 50, and a prediction unit 70, and optionally includes a control unit 10, a storage unit 20, a slurry relative permittivity measurement unit 40, a volumetric water content calculation unit 60, and a display unit (not shown).

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

[0020] The configuration of the control unit 10 is not particularly limited, and the control unit 10 can be provided within the electrical conductivity prediction system 100. Alternatively, the control unit 10 may be located away from the electrical conductivity prediction system 100 and connected to it via wired or wireless means for communication. 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 memory unit 20 is a temporary storage device that stores information calculated by the CPU when it performs processing, under the control of the control unit 10. The memory unit 20 may be located within the control unit 10.

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

[0023] The slurry electrical conductivity measurement unit 30 measures the electrical conductivity of the solidifying agent slurry. In the slurry electrical conductivity measurement unit 30 of this disclosure, the electrical conductivity of the solidifying agent slurry before mixing with the in-ground soil is measured under the control of the control unit 10, and the measured electrical conductivity of the solidifying agent slurry is stored in the storage unit 20.

[0024] The slurry dielectric constant measurement unit 40 measures the dielectric constant of the solidifying agent slurry. In the slurry dielectric constant measurement unit 40 of this disclosure, the dielectric constant of the solidifying agent slurry before mixing with the in-ground soil is measured under the control of the control unit 10, and the measured dielectric constant of the solidifying agent slurry is stored in the storage unit 20. Note that the measurement of the dielectric constant of the solidifying agent slurry may be performed simultaneously with the measurement of the electrical conductivity of the solidifying agent slurry (see Figure 1(ii)).

[0025] The slurry relative permittivity measurement unit 40 calculates a corrected value by correcting the electrical conductivity of the solidifying material slurry based on the relative permittivity of the solidifying material slurry. In the slurry relative permittivity measurement unit 40 of this disclosure, the electrical conductivity of the solidifying material slurry measured by the slurry electrical conductivity measurement unit 30 is corrected based on the relative permittivity of the solidifying material slurry measured by the slurry relative permittivity measurement unit 40 to calculate a corrected value.

[0026] The original ground relative permittivity measurement unit 50 measures the relative permittivity of the original ground. In the original ground relative permittivity measurement unit 50 of this 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 storage unit 20.

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

[0028] The prediction unit 70 predicts the electrical conductivity and variation of the electrical conductivity of the unhardened improved soil based on the water-solidifying agent ratio of the solidifying agent slurry, the electrical conductivity of the solidifying agent slurry, and the relative permittivity of the original ground.

[0029] In the prediction unit 70 of this disclosure, under the control of the control unit 10, a predicted value of the electrical conductivity of the unhardened improved soil and a predicted value of the variation range of the electrical conductivity are estimated from the water-solidifying agent ratio of the solidifying agent slurry, the slurry electrical conductivity measurement unit 30 measured by the slurry electrical conductivity measurement unit 30, and the relative permittivity of the original ground measured by the original ground relative permittivity measurement unit 50. The estimated predicted value of the electrical conductivity and the predicted value of the variation range of the electrical conductivity are stored in the storage 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. In the prediction unit 70 of this disclosure, the predicted value of the electrical conductivity of the unhardened improved soil and the predicted range of variation in electrical conductivity are estimated from the water-solidifying agent ratio of the solidifying agent slurry, the slurry electrical conductivity measurement unit 30 measured by the slurry electrical conductivity measurement unit 30, and the volumetric water content of the original ground calculated by the volumetric water content calculation 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 solidifying agent slurry, the measured relative permittivity of the solidifying agent slurry, the measured relative permittivity of the original ground, the estimated predicted value of the electrical conductivity, and the predicted value of the variation range of the electrical conductivity. 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, a tablet terminal display, etc., that is connected to the electrical conductivity prediction system 100 in a manner that enables communication via wired or wireless means.

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

[0033] First, in the derivation of the following equation, the volume and mass of the in-situ ground (soil sample) per unit volume are used as schematically shown 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 liquid phase and solid phase surface of the soil is in a parallel relationship, forming the electrical resistance 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 experimental constants, a=1.2867 and b=-0.1158, and the surface electrical conductivity of the soil particle is X S This is expressed as =0.025 S / m.

[0034]

number

[0035] The volumetric water content θ is estimated using the relative permittivity according to Topp's equation shown in the following formula (2) [Topp, G.C., Davis, J.L. and Annan, A.P.: 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 permittivity according to the following formula (2) is performed by the volumetric water content calculation unit 60 of the present disclosure.

[0036]

Equation

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

[0038]

Equation

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

[0040] ​​

number

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

[0042] The electrical conductivity of the solidifying agent slurry alone is 120 kg / m³ at a cement concentration. 3 Up to this point, the increase is linear, and beyond this point, the increase gradient decreases, and the cement concentration reaches 429 kg / m³. 3 Beyond a certain point, the concentration decreases or becomes constant. Based on this relationship, as an example, as shown in Figure 4, the cement concentration at the intersection of the approximate lines is 160 kg / m³. 3 We assume a bilinear relationship with inflection point at . That is, the electrical conductivity of the solidifying agent slurry is given by a cement concentration of 160 kg / m³. 3 Up to this point, we assume that the total molar conductivity in equation (3) above is constant and increases linearly with respect to the cement concentration, and that it remains constant beyond this concentration.

[0043] Under this bilinear assumption, the electrical conductivity within the improved soil void is estimated by equation (5) below. The cement concentration in equation (5) is obtained by equation (6) below, and the volume of the solidifying agent slurry in equation (6) is obtained by equation (7) below. Note that θ in equation (6) below g The value for the soil sample is given in the following formula (7), where ρ c = 3.04 Mg / m³ 3 ρ w = 1.00 Mg / m³ 3 This is used. At this time, the predicted value of the electrical conductivity with respect to cement concentration in the improved soil void according to the following formula (5) is shown in Figure 4.

[0044]

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[0045]

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[0046]

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[0047]

number

[0048] Using the electrical conductivity of the pore water in the improved soil obtained by equation (5) above, the apparent electrical conductivity of the improved soil is estimated by equation (1) above. Note that θ in equation (1) above is θ c Let θ c The obtained θ is given by equation (8) above. c The volumetric water content of the improved soil can be estimated. The calculation of the volumetric water content θ from the relative permittivity using the above formulas (1), (5) to (8) is performed by the volumetric water content calculation unit 60 of this disclosure.

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

[0050] Figure 8 shows the relationship between measured values ​​or their variability and predicted values ​​or their variability in the electrical conductivity of improved soil. In Figure 8, a continuous prediction of the electrical conductivity of the solidifying agent slurry mixed and stirred layer is made in the depth direction. As shown in comparison with Figure 8, the maximum value and depth of the predicted electrical conductivity generally match the measured values, so the predicted values ​​and the degree of mixing and stirring can be inferred to be generally reasonable. On the other hand, the increase gradient of electrical conductivity in the depth direction differs. In Figure 8, since the solidifying agent slurry is introduced from the surface and mixed and stirred in the depth direction, it can be inferred that there is relatively more solidifying agent slurry at the surface, and the measured value is larger there. In other words, since "mixing" in the degree of mixing and stirring refers to the amount of solidifying agent slurry mixed, and "stirring" refers to the homogeneity of the mixed layer, it can be seen that quantitative evaluation can be made from both mixing and stirring aspects in this disclosure.

[0051] In the improved soil electrical conductivity prediction system 100 described herein, as described above, the electrical conductivity and electrical conductivity variation of the unhardened improved soil are estimated based on the water-solidifying agent ratio of the solidifying agent slurry, the electrical conductivity of the solidifying agent slurry, and the relative permittivity of the original ground. This makes it possible to understand the mix design conditions for the improved soil before construction.

[0052] The electrical conductivity prediction system 100 of this disclosure further predicts the electrical conductivity and variation of electrical conductivity of the unhardened improved soil based on the volumetric water content of the original ground calculated from the relative permittivity, thereby enabling accurate determination of the mix design conditions for the improved soil before construction.

[0053] Furthermore, in the electrical conductivity prediction system 100 of this disclosure, the corrected value obtained by correcting the electrical conductivity of the solidifying agent slurry based on the relative permittivity of the solidifying agent slurry is calculated using the following equations (9) and (10).

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

[0055]

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[0056]

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[0057] The calculated correction value represents the electrical conductivity of the pore water. By using this correction value, which corrects the electrical conductivity of the solidifying agent slurry based on its relative permittivity, the mix design conditions for the improved soil can be determined more accurately before construction.

[0058] <Quality Verification System> The quality confirmation system of the present disclosure includes a quality determination unit 80. The quality determination unit 80 determines the quality of the improved soil by comparing the predicted value of the electrical conductivity of the unhardened improved soil and / or the predicted value of the variation in electrical conductivity, predicted by the improved soil electrical conductivity prediction system of the present disclosure, with the measured value of the electrical conductivity of the unhardened improved soil and / or the measured value of the variation in electrical conductivity.

[0059] The quality determination unit 80 can be configured as part of the electrical conductivity prediction system 100 described above, as shown in Figure 2.

[0060] The quality determination unit 80, under the control of the control unit 10, compares the predicted value of electrical conductivity with the measured value of electrical conductivity. The quality determination unit 80 also, under the control of the control unit 10, compares the predicted variation range of electrical conductivity with the measured variation range of electrical conductivity. Based on the comparison results, the quality determination unit 80, under the control of the control unit 10, determines the quality of the improved soil. The comparison results and the determined quality results are stored in the storage unit 20 under the control of the control unit 10.

[0061] The quality of the improved soil that can be determined by the quality determination unit 80 includes, for example, the degree of mixing and stirring when the solidifying agent slurry is mixed and stirred with the original ground, and the amount of cement-based solidifying agent used.

[0062] The quality judgment unit 80 takes input such as the relative permittivity of the original ground measured in the depth direction and the electrical conductivity of the solidifying agent slurry to be mixed, and displays a predicted value of the electrical conductivity in the depth direction in the unhardened improved ground. It also allows input and setting of upper and lower limits (predicted range of variation) for the predicted value. Furthermore, it displays the measured value in the depth direction measured after mixing and stirring, compares it with the predicted value and range of variation, and indicates whether the mixing or stirring was good or bad at the total depth or a specific depth. If the judgment is bad, remixing and re-stirring can be performed immediately on site.

[0063] The quality verification system of this disclosure further includes a ground electrical conductivity measurement unit 90. The ground electrical conductivity measurement unit 90 measures the electrical conductivity of the ground. The ground electrical conductivity measurement unit 90 of this disclosure can be configured as part of the electrical conductivity prediction system 100 described above, as shown in Figure 2.

[0064] In the in-ground electrical conductivity measurement unit 90 of this disclosure, the electrical conductivity of the in-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 in-ground is stored in the storage unit 20.

[0065] The quality confirmation system disclosed herein further compares the predicted value of the electrical conductivity and / or the predicted value of the variation in electrical conductivity of the unhardened improved soil with the measured value of the electrical conductivity of the original ground and the measured value of the relative permittivity and / or the measured value of the variation in electrical conductivity of the original ground in the quality determination unit 80 described above. The quality determination unit 80 then 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 storage unit 20 under the control of the control unit 10.

[0066] In the quality verification system disclosed herein, as described above, the quality of the improved soil is determined by comparing the predicted value of the electrical conductivity and / or the predicted value of the variation in electrical conductivity of the unhardened improved soil with the measured value of the electrical conductivity and / or the measured value of the variation in electrical conductivity of the unhardened improved soil. This makes it possible to determine the appropriate mix conditions for the improved soil before construction.

[0067] As described above, the quality confirmation system disclosed herein allows for the determination of the degree of mixing and stirring when the solidification agent slurry is mixed and stirred with the original ground, thereby enabling the determination of the appropriate degree of mixing and stirring of the improved soil before construction.

[0068] In the quality confirmation system disclosed herein, as described above, the quality of the improved soil that can be judged is the amount of cement-based solidifying agent used, making it possible to determine the amount of cement-based solidifying agent used before construction.

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

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

[0071] The method for predicting the electrical conductivity of improved soil according to this disclosure includes a step of measuring the electrical conductivity of a solidifying agent slurry. In the electrical conductivity prediction method according to this disclosure, as shown in Figure 9, the relative permittivity and electrical conductivity of a solidifying agent slurry with a specified water-solidifying agent ratio are measured (step S1). The step of measuring the electrical conductivity of the solidifying agent slurry according to this disclosure can be performed by the slurry electrical conductivity measurement unit 30 described above.

[0072] The method for predicting the electrical conductivity of improved soil according to this disclosure includes a step of measuring the relative permittivity and electrical conductivity of the in-ground ground. In this disclosure, the step of measuring the relative permittivity and electrical conductivity of the in-ground ground is to measure the relative permittivity and electrical conductivity of the in-ground ground as shown in Figure 10 (step S2). The step of measuring the relative permittivity and electrical conductivity of the in-ground ground according to this disclosure can be performed by the in-ground relative permittivity measuring unit 50 and the in-ground electrical conductivity measuring unit 90 described above.

[0073] The method for predicting the electrical conductivity of improved soil according to this disclosure includes a step of calculating the volumetric water content of the original ground from the relative permittivity. In this disclosure, the step of calculating the volumetric water content of the original ground from the relative permittivity is performed by calculating the volumetric water content of the original ground from the relative permittivity measured in step S2 (step S3), as shown in Figure 10. The step of calculating the volumetric water content according to this 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 this disclosure includes a step of predicting the electrical conductivity and the variation in electrical conductivity of the unhardened improved soil based on the water-solidifying agent ratio of the solidifying agent slurry, the electrical conductivity of the solidifying agent slurry, and the volumetric water content of the original ground. In this disclosure, the step of predicting the electrical conductivity and the variation range of electrical conductivity is, as shown in Figure 11, to predict the electrical conductivity and the variation range of electrical conductivity 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 solidifying agent slurry, and the water-solidifying agent ratio of the solidifying agent slurry (step S4). The prediction step in this disclosure can be performed by the prediction unit 70 described above.

[0075] The method for predicting the electrical conductivity of improved soil according to this disclosure includes a step of prediction based on the water-solidifying agent ratio of the solidifying agent slurry, the electrical conductivity of the solidifying agent slurry, and the volumetric water content of the original ground, as described above. This provides the same effect as the improved soil electrical conductivity prediction system 100 described above. In other words, the method for predicting the electrical conductivity of improved soil according to this disclosure allows for the determination of the soil mix conditions before construction.

[0076] <Method for checking the quality of improved soil> Figure 12 is a process diagram for measuring the electrical conductivity of improved soil, and Figure 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 this disclosure includes a step of determining the quality of the improved soil by 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 according to this disclosure, with the measured value of the electrical conductivity of the unhardened improved soil.

[0077] Furthermore, the method for confirming the quality of improved soil according to this disclosure includes a step of determining the quality of the improved soil by comparing the predicted value of the variation in the electrical conductivity of the unhardened improved soil, predicted by the method for predicting the electrical conductivity of improved soil according to this disclosure, with the measured value of the variation in the electrical conductivity of the unhardened improved soil.

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

[0079] The process for determining the quality of improved soil in this disclosure, as shown in Figure 13, first involves comparing the predicted value of electrical conductivity with the measured value of electrical conductivity, and / or comparing the predicted range of variation in electrical conductivity with the measured range of variation in electrical conductivity (Step S7). Next, it is determined whether the predicted value of electrical conductivity or the predicted range of variation in electrical conductivity is within the range of the measured range of variation in electrical conductivity (Step S8).

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

[0081] The method for confirming the quality of improved soil according to this disclosure includes a step of determining the quality of the improved soil by comparing the predicted value of the electrical conductivity of the unhardened improved soil, predicted by the electrical conductivity prediction method for improved soil, with the measured value of the electrical conductivity of the unhardened 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 method for confirming the quality of improved soil according to this disclosure makes it possible to determine the appropriate mix conditions for the improved soil before construction.

[0082] The method for confirming the quality of improved soil according to this disclosure includes a step of determining the quality of the improved soil by comparing the predicted value of the variation in the electrical conductivity of the unhardened improved soil, predicted by the electrical conductivity prediction method for improved soil, with the measured value of the variation in the electrical conductivity of the unhardened 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 method for confirming the quality of improved soil according to this disclosure makes it possible to determine more appropriate mix conditions for the improved soil before construction.

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

[0084] <1> An improved soil electrical conductivity prediction system predicts the electrical conductivity in the depth direction of unhardened improved soil obtained by mixing a solidification slurry, which is a mixture of cement-based solidification material and mixing water, with the original ground and stirring it, A slurry electrical conductivity measuring unit for measuring the electrical conductivity of the solidifying material slurry, A ground relative permittivity measuring unit for measuring the relative permittivity of the ground, The system includes a prediction unit that estimates the electrical conductivity and variation of the unhardened improved soil based on the water-solidifying agent ratio of the solidifying agent slurry, the electrical conductivity of the solidifying agent slurry, and the relative permittivity of the original ground. A system for predicting the electrical conductivity of improved soil.

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

[0086] <3> The system further includes a slurry relative permittivity measuring unit for measuring the relative permittivity of the solidification material slurry, A corrected value is calculated by correcting the electrical conductivity of the solidifying agent slurry based on the relative permittivity of the solidifying agent slurry. The aforementioned <1> or <2> A system for predicting the electrical conductivity of improved soil as described above.

[0087] <4> The aforementioned <1> ~ <3> The system has 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 electrical conductivity of the unhardened improved soil, predicted by the improved soil electrical conductivity prediction system described in any one of the above, with the measured value of the electrical conductivity and / or the measured value of the variation in electrical conductivity of the unhardened improved soil. A system for verifying the quality of improved soil.

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

[0089] <6> The quality of the improved soil is determined by the amount of cement-based solidifying agent used in the mixture. The aforementioned <4> The quality verification system for improved soil as described above.

[0090] <7> It has a ground electrical conductivity measuring unit for measuring the electrical conductivity of the ground, The prediction unit compares the predicted value of the electrical conductivity and / or the predicted value of the variation in electrical conductivity of the unhardened improved soil with the measured value of the electrical conductivity and / or the measured value of the variation in electrical conductivity of the original ground. The aforementioned <4> ~ <6> A quality verification system for improved soil described in any one of the following:

[0091] <8> A method for predicting the electrical conductivity of improved soil, which involves mixing a cement-based solidifying agent slurry, obtained by mixing a solidifying agent slurry (a mixture of cement-based solidifying agent and mixing water) with the original ground, and then stirring the unhardened improved soil to predict its electrical conductivity in the depth direction. A step of measuring the electrical conductivity of the solidifying agent slurry, A step of measuring the relative permittivity of the in-ground ground, A step of calculating the volumetric water content of the original ground from the relative permittivity, The process includes predicting the electrical conductivity of the unhardened improved soil and the variation in electrical conductivity based on the water-solidifying agent ratio of the solidifying agent slurry, the electrical conductivity of the solidifying agent 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> The method includes a step of determining the quality of the improved soil by 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 above, with the measured value of the electrical conductivity of the unhardened improved soil. Methods for checking the quality of improved soil.

[0093] <10> The aforementioned <8> or <9> The method includes a step of determining the quality of the improved soil by comparing the predicted value of the variation in the electrical conductivity of the unhardened improved soil, predicted by the method for predicting the electrical conductivity of improved soil described above, with the measured value of the variation in the electrical conductivity of the unhardened improved soil. Methods for checking the quality of improved soil.

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

[0095] 1 pipe 2 Model ground (original ground) 3. Cone Penetration Tester 4 containers 5. Solidifying agent 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. Measurement section for the relative permittivity of the original ground. 60 Volumetric water content calculation unit 70 Prediction Section 80 Quality Judgment Department 90. Measurement section for electrical conductivity of the ground 100 Electrical Conductivity Prediction System

Claims

1. An improved soil electrical conductivity prediction system predicts the electrical conductivity in the depth direction of unhardened improved soil obtained by mixing a solidification slurry, which is a mixture of cement-based solidification material and mixing water, with the original ground and stirring it, A slurry electrical conductivity measuring unit for measuring the electrical conductivity of the solidifying material slurry, A ground relative permittivity measuring unit for measuring the relative permittivity of the ground, The system includes a prediction unit that estimates the electrical conductivity and variation of the unhardened improved soil based on the water-solidifying agent ratio of the solidifying agent slurry, the electrical conductivity of the solidifying agent slurry, and the relative permittivity of the original ground. A system for predicting the electrical conductivity of improved soil.

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

3. The system further includes a slurry relative permittivity measuring unit for measuring the relative permittivity of the solidification material slurry, A corrected value is calculated by correcting the electrical conductivity of the solidifying agent slurry based on the relative permittivity of the solidifying agent slurry. The electrical conductivity prediction system for improved soil according to claim 1.

4. 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 electrical conductivity of the unhardened improved soil, predicted by the improved soil electrical conductivity prediction system according to any one of claims 1 to 3, with the measured value of the electrical conductivity and / or the measured value of the variation in electrical conductivity of the unhardened improved soil. A system for verifying the quality of improved soil.

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

6. The quality of the improved soil is determined by the amount of cement-based solidifying agent used in the mixture. The quality confirmation system for improved soil according to claim 4.

7. It has a ground electrical conductivity measuring unit for measuring the electrical conductivity of the ground, In the quality determination unit, the predicted value of the electrical conductivity and / or the predicted value of the variation in electrical conductivity of the unhardened improved soil is compared with the measured value of the electrical conductivity of the original ground and the measured value of the relative permittivity and / or the measured value of the variation in electrical conductivity of the original ground. The quality confirmation system for improved soil according to claim 4.

8. A method for predicting the electrical conductivity of improved soil, which involves mixing a cement-based solidifying agent slurry, obtained by mixing a solidifying agent slurry (a mixture of cement-based solidifying agent and mixing water) with the original ground, and then stirring the unhardened improved soil to predict its electrical conductivity in the depth direction. A step of measuring the electrical conductivity of the solidifying agent slurry, A step of measuring the relative permittivity of the in-ground ground, A step of calculating the volumetric water content of the original ground from the relative permittivity, The process includes predicting the electrical conductivity of the unhardened improved soil and the variation in electrical conductivity based on the water-solidifying agent ratio of the solidifying agent slurry, the electrical conductivity of the solidifying agent slurry, and the volumetric water content of the original ground. A method for predicting the electrical conductivity of improved soil.

9. The method comprises a step of determining the quality of the improved soil by 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 according to claim 8, with the measured value of the electrical conductivity of the unhardened improved soil. Methods for checking the quality of improved soil.

10. The method comprises a step of determining the quality of the improved soil by comparing a predicted value of the variation in the electrical conductivity of the unhardened improved soil, predicted by the method for predicting the electrical conductivity of improved soil according to claim 8, with an actual measured value of the variation in the electrical conductivity of the unhardened improved soil. Methods for checking the quality of improved soil.

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