Method for calculating permeability coefficient of fine-grained soil by considering internal connected pore characteristics
By constructing a quantitative relationship between pore parameters and permeability coefficient of fine-grained soil and combining it with plasticity index data, the problems of insufficient accuracy and excessively long calculation cycle of permeability coefficient in existing technologies have been solved, realizing high-precision and short-time permeability coefficient prediction and supporting engineering design.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NORTHWEST ENGINEERING CORPORATION LIMITED
- Filing Date
- 2026-03-05
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies neglect the microscopic pore structure when calculating the permeability coefficient of fine-grained soil, resulting in insufficient calculation accuracy and excessively long test cycles, making it difficult to meet engineering requirements.
By constructing a quantitative relationship between pore parameters and permeability coefficient of fine-grained soil, and combining plasticity index data, liquid limit test and mercury intrusion porosimetry test are used to establish a quantitative relationship between permeability characterization parameters and plasticity index, and to predict the permeability coefficient of fine-grained soil.
It achieves high-precision, short-time permeability coefficient calculation, providing accurate technical support for the design of foundations, slope engineering, and environmental geotechnical isolation walls.
Smart Images
Figure CN122016601A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for calculating the permeability coefficient of fine-grained soil that takes into account the characteristics of internally connected pores, belonging to the field of foundation technology. Background Technology
[0002] Fine-grained soils (such as clay and silty clay) are widely used in foundation engineering, slope engineering, and environmental soil and rock barrier projects. Their permeability coefficient, as a core parameter characterizing permeability, directly determines the settlement rate of the foundation, the stability of the slope, and the seepage prevention effect of the barrier. Therefore, accurately obtaining the permeability coefficient of fine-grained soils plays an irreplaceable role in engineering design and safety management.
[0003] Currently, the methods for calculating the permeability coefficient of fine-grained soil are mainly divided into two categories: empirical formula methods and experimental testing methods. However, both have significant limitations, as follows: (1) The empirical formula method usually uses macroscopic physical indicators such as dry density and void ratio to establish the relationship between them and the permeability coefficient. However, this method simplifies the pores inside the soil as a homogeneous connected medium and fails to consider the "connectivity difference" of the pore system—that is, the difference between "connected pores" that actually contribute to permeability and "closed pores" that do not contribute. Since it ignores key microscopic characteristics such as the number and pore size distribution of connected pores, the method can have an error of 1 to 3 orders of magnitude when calculating high void ratio, heterogeneous fine-grained soils, which is difficult to meet the requirements of high-precision engineering.
[0004] (2) Although experimental testing methods (such as the constant head method or the variable head method) can directly determine the permeability coefficient, fine-grained soils have extremely low permeability (for example, the permeability coefficient of expansive soil is often less than 1×10⁻⁶). -9 The permeability coefficient (C / s) can be measured in cm / s, and a single indoor test can take weeks or even months, resulting in low efficiency. In addition, mechanical disturbance during undisturbed soil sampling can alter the internal pore structure of the soil and disrupt the original distribution of interconnected pores, leading to deviations between the test results and the actual permeability coefficient under working conditions. Therefore, it is not suitable for engineering sites that require rapid calculations.
[0005] In summary, given the technical limitations of existing methods, such as neglecting microscopic pore structure, insufficient calculation accuracy, and excessively long testing cycles, there is an urgent need to establish a new method for calculating permeability coefficients. Summary of the Invention
[0006] This invention provides a method for calculating the permeability coefficient of fine-grained soil that considers the characteristics of internally connected pores, which can solve the problems of existing methods ignoring the microscopic pore structure, insufficient calculation accuracy, and excessively long testing cycles.
[0007] This invention provides a method for calculating the permeability coefficient of fine-grained soil considering the characteristics of internally interconnected pores, the method comprising: S1. Construct the first quantitative relationship between pore parameters, permeability characterization parameters and permeability coefficient of fine-grained soil; S2. Determine the plasticity index data and permeability characterization data of various fine-grained soil samples, and construct a second quantitative relationship between the plasticity index and permeability characterization parameters of fine-grained soil based on the plasticity index data and the permeability characterization data. S3. Determine the measured value of the plasticity index of the target fine-grained soil, and determine the predicted value of the permeability characterization parameter of the target fine-grained soil based on the measured value of the plasticity index and the second quantitative relationship. S4. Determine the measured values of the pore parameters of the target fine-grained soil, and determine the predicted value of the permeability coefficient of the target fine-grained soil based on the measured values of the pore parameters, the predicted values of the permeability characterization parameters, and the first quantitative relationship.
[0008] Optionally, determining the permeability characterization data of various fine-grained soil samples in S2 specifically includes: Each type of fine-grained soil sample was prepared into multiple sub-samples with different dry densities, and the pore parameters and permeability coefficients of each sub-sample were determined. The permeability characterization data of the corresponding fine-grained soil sample is determined based on the pore parameter data and permeability coefficient data of all sub-samples in the same type of fine-grained soil sample.
[0009] Optionally, determine the pore parameter data for each subsample, specifically including: Mercury intrusion porosimetry was performed on each subsample to obtain the pore parameter data of the corresponding subsample.
[0010] Optionally, determine the permeability coefficient data for each sample, specifically including: An indoor constant head permeability test was conducted on each subsample to obtain the permeability coefficient data for the corresponding subsample.
[0011] Optionally, the permeability characterization data of the corresponding fine-grained soil sample can be determined based on the pore parameter data and permeability coefficient data of all sub-samples in the same fine-grained soil sample, specifically including: Multiple assumed values for the permeability characterization parameters are preset, and each assumed value and the pore parameter data of each sub-sample are substituted into the independent variable part of the first quantitative relationship to obtain the calculated value of the independent variable part of each sub-sample under each assumed value. Based on the calculated values of the independent variables of all sub-samples in the same type of fine-grained soil sample under each assumed value and the first quantitative relationship, the theoretical straight line of the permeability coefficient of the corresponding fine-grained soil sample under the corresponding assumed value is determined. Based on the theoretical straight line of the permeability coefficient of each fine-grained soil sample under each assumed value and the permeability coefficient data of all sub-samples of the corresponding fine-grained soil sample, the permeability characterization data of the corresponding fine-grained soil sample are determined.
[0012] Optionally, determining the plasticity index data of various fine-grained soil samples in S2 specifically includes: Liquid limit and plastic limit tests were conducted on various fine-grained soil samples to obtain plasticity index data for each sample.
[0013] Optionally, the second quantitative relationship between the plasticity index and permeability characterization parameters of fine-grained soil constructed in step S2 based on the plasticity index data and the permeability characterization data specifically includes: The plasticity index data and the permeability characterization data are subjected to nonlinear fitting to obtain a second quantitative relationship between the plasticity index and permeability characterization parameters of fine-grained soil. The second quantitative relationship is a power function.
[0014] Optionally, the pore parameters include porosity, the number of pores per cross section in the fine-grained soil, and the diameter of each pore.
[0015] The beneficial effects that this invention can produce include: This invention provides a method for calculating the permeability coefficient of fine-grained soil considering the characteristics of internally connected pores. It proposes permeability characterization parameters for the permeability coefficient of fine-grained soil and establishes quantitative relationships between these parameters and the permeability coefficient and plasticity index. In practical prediction, only liquid limit and plastic limit tests and mercury intrusion porosimetry tests are needed to obtain the plasticity index, porosity, pore size, and number of the target fine-grained soil; then the permeability coefficient can be calculated. This method can more accurately predict and calculate the permeability coefficient of fine-grained soil, providing technical support for the design of foundations, slope engineering, and environmental geotechnical retaining walls.
[0016] This invention provides a method for calculating the permeability coefficient of fine-grained soil considering the characteristics of internally connected pores. It presents a detailed derivation of the relationship between the permeability coefficient and the internal interconnected pores of the soil layer, with clear physical and mechanical concepts and a highly refined formula, thus achieving high accuracy in permeability coefficient calculation. When calculating the permeability coefficient of fine-grained soil using the formula of this invention, only liquid limit and plastic limit tests and mercury intrusion porosimetry tests are required to obtain the soil's plasticity index, porosity, pore size, and number. Liquid limit and plastic limit tests and mercury intrusion porosimetry tests are time-efficient and yield highly accurate results; therefore, the calculation of the permeability coefficient is also time-efficient and highly accurate. Attached Figure Description
[0017] Figure 1 A flowchart of a method for calculating the permeability coefficient of fine-grained soil considering the characteristics of internally connected pores, provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of single-hole seepage provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of seepage in a single cross-section inside fine-grained soil, provided in an embodiment of the present invention. Figure 4This is a schematic diagram of seepage when two cross sections are formed inside fine-grained soil, as provided in an embodiment of the present invention. Figure 5 The interior of fine-grained soil provided in the embodiments of the present invention Schematic diagram of seepage when composed of multiple cross sections; Figure 6 A schematic diagram illustrating the pore size and number of fine-grained soil provided in an embodiment of the present invention; Figure 7 Permeation characterization parameters provided for embodiments of the present invention A schematic diagram showing the predicted permeability coefficient line and the measured permeability coefficient of a fine-grained soil sample with a value of 1. Figure 8 Permeation characterization parameters provided for embodiments of the present invention A schematic diagram showing the predicted permeability coefficient and the measured permeability coefficient of a fine-grained soil sample at time 2. Figure 9 Permeation characterization parameters provided for embodiments of the present invention This is a schematic diagram showing the predicted permeability coefficient line and the measured permeability coefficient of the fine-grained soil sample at time 3. Figure 10 Permeation characterization parameters provided for embodiments of the present invention This is a schematic diagram showing the predicted permeability coefficient line and the measured permeability coefficient of a fine-grained soil sample at time 4. Figure 11 Permeation characterization parameters provided for embodiments of the present invention With plasticity index Schematic diagram of the relationship curve; Figure 12 This is a schematic diagram comparing the predicted and measured values of the permeability coefficient provided in an embodiment of the present invention. Detailed Implementation
[0018] The present invention will now be described in detail with reference to the embodiments, but the present invention is not limited to these embodiments.
[0019] This invention provides a method for calculating the permeability coefficient of fine-grained soil considering the characteristics of internally connected pores, such as... Figure 1 As shown, the method includes: S1. Construct the first quantitative relationship between the pore parameters, permeability characterization parameters and permeability coefficient of fine-grained soil.
[0020] The above pore parameters include porosity. Number of pores per cross section in fine-grained soil and the diameter of each channel The probability that any two channels on two adjacent cross sections in fine-grained soil are connected. .
[0021] The specific construction process of the first quantitative relationship is described in detail below.
[0022] Fine-grained soil contains numerous pores. Poiseuille assumed that each individual pore is circular in shape and has a diameter of [missing information]. ,See Figure 2 As shown. Although the pore shape inside fine-grained soil is not perfectly circular, existing studies based on the circularity assumption and the Poiseuille equation have found that it can well describe and predict the permeability coefficient of fine-grained soil. Therefore, this invention also adopts this assumption, that is, it does not consider the influence of pore shape. Poiseuille considers the flow of liquid water in a single pore to be laminar flow, and the flow rate of liquid water through a single pore per unit time is derived based on theoretical methods. As shown in equation (1): (1) In formula (1) The diameter of a single hole; Water head pressure; The seepage length; Let be the viscosity coefficient of water. Transforming equation (1) (see equation (2)) yields the single-pore permeability coefficient. See equation (3).
[0023] (2)
[0024] (3) In formula (2) For hydraulic gradient, The water head height; in equation (3) Permeability coefficient, ρ w The density of water, This is the acceleration due to gravity.
[0025] The study focuses on a single cross-section within fine-grained soil (see...). Figure 3 As shown), the volume of permeable pores on the cross-section is The impermeable volume is The total volume is The porosity of the sample is There exists on the cross-section One channel, numbered as The area of each single hole on the cross-section is respectively The values are successively equal to ,in for The proportion of pores in the cross-section can be obtained from mercury intrusion porosimetry. Based on equation (3), the permeability coefficient of this cross-section can be derived. The details are shown below. It should be noted that the physical concepts from the single-pore permeability coefficient (Equation 3) to the cross-sectional permeability coefficient (Equation 9) are clear and straightforward. The cross-sectional permeability coefficient is the sum of the single-pore permeability coefficients, but it needs to be multiplied by the probability of a single pore appearing on the cross-section, i.e. .
[0026] (4)
[0027] (5)
[0028] (6)
[0029] (7)
[0030] (8)
[0031] (9) In equation (9) For the first The diameter of each channel, for Kong Zai The proportion of pores in the cross-section.
[0032] In fact, fine-grained soils (including undisturbed and remolded fine-grained soils) consist of many cross-sections. For water to penetrate the sample during seepage, the pores on each cross-section must be interconnected. Taking two adjacent cross-sections 1 and 2 inside the sample as examples (see...),... Figure 4 As shown in the figure, assuming the soil sample is in a homogeneous state, the porosity of each cross-section inside the sample is 1. (Same porosity as the sample), both sections contain If there are 10 channels, and the number of identical channels is equal on each cross section, then on cross section 1... On single-hole connected section 2 The probability of a single hole is By employing a derivation process similar to that of equation (9), the permeability coefficient of fine-grained soil after combining the two sections can be obtained. The calculation formula is shown in equation (10): (10) In formula (10) For section 1, the first The diameter of each channel, For section 2, the first The diameter of each channel, for and The smaller pore size is used because, in the case of two interconnected pores, soil permeability depends primarily on the smaller pore. By analogy, the permeability coefficient for numerous cross-sectional combinations can be obtained (see...). Figure 5 As shown in the figure, the first quantitative relationship has been established, specifically as shown in equation (11). Equation (11) contains only one unknown parameter. (Other parameters can be obtained through experimental testing), and this unknown parameter is called the permeability characterization parameter of the permeability coefficient, which can reflect the influence of the characteristics of connected pores. In practical applications, equation (11) can be transformed to obtain equation (12). The expression of PSP in equation (12) is shown in equation 13, where PSP is the independent variable composed of pore parameters and permeability characterization parameters.
[0033] (11)
[0034] (12)
[0035] (13)
[0036] S2. Determine the plasticity index data and permeability characterization data of various fine-grained soil samples, and construct a second quantitative relationship between the plasticity index and permeability characterization parameters of fine-grained soil based on the plasticity index data and permeability characterization data.
[0037] (1) The plasticity index data for various fine-grained soil samples determined above specifically include: Liquid limit and plastic limit tests were conducted on various fine-grained soil samples to obtain plasticity index data for each sample.
[0038] (2) The permeability characterization data for various fine-grained soil samples determined above specifically include: a) Prepare multiple sub-samples with different dry densities for each type of fine-grained soil sample, and determine the pore parameter data and permeability coefficient data for each sub-sample.
[0039] In practical applications, mercury intrusion porosimetry and constant head permeability tests are conducted on fine-grained soil to obtain pore parameter data (including total porosity n, pore diameter and the number of pores) and permeability coefficient data for each sample of fine-grained soil.
[0040] Taking compacted loess with a moisture content of 13.7% as an example, three compacted loess samples with different dry densities were prepared indoors (values were 1.79 g / cm³, respectively). 3 1.611 g / cm 3 and 1.432 g / cm 3 Then, mercury intrusion porosimetry was used to test the pore parameters of three compacted loess samples, including pore distribution and quantity (at a ratio of 1.79 g / cm³). 3For example, see the results of the 100% compaction test sample. Figure 6 (As shown). Furthermore, for the three compacted loess samples with different dry densities mentioned above, indoor constant head permeability tests were conducted to determine their permeability coefficients, i.e., permeability coefficients. .
[0041] b) Determine the permeability characterization data of the corresponding fine-grained soil sample based on the pore parameter data and permeability coefficient data of all sub-samples in the same type of fine-grained soil sample.
[0042] Specifically, it includes: Multiple assumed values for the permeability characterization parameters are preset, and each assumed value and the pore parameter data of each sub-sample are substituted into the independent variable part of the first quantitative relationship to obtain the calculated value of the independent variable part of each sub-sample under each assumed value. Based on the calculated values of the independent variables of all sub-samples in the same type of fine-grained soil sample under each assumed value and the first quantitative relationship, the theoretical straight line of the permeability coefficient of the corresponding fine-grained soil sample under the corresponding assumed value is determined. Based on the theoretical straight line of the permeability coefficient of each fine-grained soil sample under each assumed value and the permeability coefficient data of all sub-samples of the corresponding fine-grained soil sample, the permeability characterization data of the corresponding fine-grained soil sample are determined.
[0043] Setting permeation characterization parameters Multiple assumed values (such as) ), and based on each assumed value and the pore parameter data (section porosity) of each sub-sample. The pore diameter and the number of pores per section; since it is assumed that the fine-grained soil is a homogeneous sample, the pore parameter data on each section are the same) and Equation (13) can be used to calculate the pore parameters and permeability characterization parameters. The independent variable component (i.e., PSP) is calculated. Since PSP is known, it can be plotted according to equation (12). The theoretical straight lines for the permeability coefficient of fine-grained soil samples under each assumed value are shown below. Figure 7 , Figure 8 , Figure 9 as well as Figure 10 .
[0044] At the same time, the permeability coefficient data (i.e., the measured permeability coefficient values) of each sub-sample of the fine-grained soil sample obtained from the experiment were put into... Figure 7 , Figure 8 , Figure 9 and Figure 10 In a specific Numerical values indicate that when the theoretical straight line of permeability matches the measured value of permeability well, it means... This assumed value is the permeability characterization data (i.e., the permeability coefficient characterization value) for this type of fine-grained soil. From Figures 7 to 10The permeability characterization parameters of the compacted loess samples in this experiment can be determined. The value is 3. Based on this method, pore parameters and permeability coefficients of different fine-grained soils (such as bentonite and clay) can be tested indoors, thus determining the permeability characterization parameters of different fine-grained soils. Numerical value.
[0045] (3) The second quantitative relationship between the plasticity index and permeability characterization parameters of fine-grained soil, constructed based on the plasticity index data and permeability characterization data, specifically includes: Nonlinear fitting was performed on the plasticity index data and permeability characterization data to obtain a second quantitative relationship between the plasticity index and permeability characterization parameters of fine-grained soil. The second quantitative relationship is a power function.
[0046] This invention establishes permeation characterization parameters Plasticity index of fine-grained soil The second quantitative relationship between them is as follows: Figure 11 As shown in equation (14).
[0047] (14)
[0048] S3. Determine the measured value of the plasticity index of the target fine-grained soil, and determine the predicted value of the permeability characterization parameter of the target fine-grained soil based on the measured value of the plasticity index and the second quantitative relationship.
[0049] In practical applications, the measured value of the plasticity index of the target fine-grained soil (including undisturbed or remolded fine-grained soil) can be obtained through the liquid limit and plastic limit test; then, the measured value of the plasticity index is substituted into equation (14) to determine the permeability characterization parameters of the target fine-grained soil. Predicted value.
[0050] S4. Determine the measured values of the pore parameters of the target fine-grained soil, and determine the predicted value of the permeability coefficient of the target fine-grained soil based on the measured values of the pore parameters, the predicted values of the permeability characterization parameters, and the first quantitative relationship.
[0051] In practical applications, mercury intrusion porosimetry can be used to directly measure the pore parameters (including porosity) of the target fine-grained soil. , channel diameter and number of channels ) Measured values, then combined with permeability characterization parameters The permeability coefficient of the target fine-grained soil can be calculated from the predicted value and equations (11) to (14). Predicted value.
[0052] Figure 12 The comparison between the predicted and measured permeability coefficients obtained by this method is presented. The figure shows a good agreement, demonstrating the effectiveness and accuracy of the proposed method.
[0053] This invention proposes permeability characterization parameters that consider the characteristics of interconnected pores and establishes a quantitative relationship between these parameters and the plasticity index of fine-grained soils. In subsequent applications, the plasticity index of the fine-grained soil is used to determine its permeability characterization parameters, and then mercury intrusion porosimetry (MIP) is used to determine the internal pore parameters. Based on the MIP results and the permeability characterization parameters, the permeability coefficient of the fine-grained soil can be calculated. This method can more accurately predict and calculate the permeability coefficient of fine-grained soils, providing technical support for the design of foundations, slope engineering, and environmental geotechnical retaining walls.
[0054] Based on the above-described invention and calculation steps, it can be seen that the present invention has the following advantages: (1) This invention provides a detailed derivation process of the permeability coefficient and the interconnected pores inside the soil layer. The physical and mechanical concepts are clear and the formula is highly refined, so it has a high accuracy in calculating the permeability coefficient.
[0055] (2) When calculating the permeability coefficient of fine-grained soil using the formula in this invention, only liquid limit test and mercury intrusion porosimetry test are required to obtain the plasticity index, porosity, pore diameter and quantity of fine-grained soil. Liquid limit test and mercury intrusion porosimetry test are time-saving and the test results are highly accurate. Therefore, the calculation of permeability coefficient is also time-saving and highly accurate.
[0056] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A method for calculating the permeability coefficient of fine-grained soil considering the characteristics of internally interconnected pores, characterized in that, The method includes: S1. Construct the first quantitative relationship between pore parameters, permeability characterization parameters and permeability coefficient of fine-grained soil; S2. Determine the plasticity index data and permeability characterization data of various fine-grained soil samples, and construct a second quantitative relationship between the plasticity index and permeability characterization parameters of fine-grained soil based on the plasticity index data and the permeability characterization data. S3. Determine the measured value of the plasticity index of the target fine-grained soil, and determine the predicted value of the permeability characterization parameter of the target fine-grained soil based on the measured value of the plasticity index and the second quantitative relationship. S4. Determine the measured values of the pore parameters of the target fine-grained soil, and determine the predicted value of the permeability coefficient of the target fine-grained soil based on the measured values of the pore parameters, the predicted values of the permeability characterization parameters, and the first quantitative relationship.
2. The method according to claim 1, characterized in that, The determination of permeability characterization data for various fine-grained soil samples in S2 specifically includes: Each type of fine-grained soil sample was prepared into multiple sub-samples with different dry densities, and the pore parameters and permeability coefficients of each sub-sample were determined. The permeability characterization data of the corresponding fine-grained soil sample is determined based on the pore parameter data and permeability coefficient data of all sub-samples in the same type of fine-grained soil sample.
3. The method according to claim 2, characterized in that, Determine the pore parameter data for each subsample, specifically including: Mercury intrusion porosimetry was performed on each subsample to obtain the pore parameter data of the corresponding subsample.
4. The method according to claim 2, characterized in that, Determine the permeability coefficient data for each sample, specifically including: An indoor constant head permeability test was conducted on each subsample to obtain the permeability coefficient data for the corresponding subsample.
5. The method according to claim 2, characterized in that, Based on the pore parameter data and permeability coefficient data of all sub-samples in the same type of fine-grained soil sample, the permeability characterization data of the corresponding fine-grained soil sample are determined, specifically including: Multiple assumed values for the permeability characterization parameters are preset, and each assumed value and the pore parameter data of each subsample are substituted into the independent variable part of the first quantitative relationship to obtain the calculated value of the independent variable part of each subsample under each assumed value; the expression of the independent variable part is: ; Wherein, PSP is the independent variable of the first quantitative relationship; This is a permeation characterization parameter, whose assumed value is an integer greater than or equal to 1; Porosity; This represents the number of pores per cross-section in the fine-grained soil. It is the smallest aperture among all the apertures; for Kong Zai The proportion of pores in the cross-section; Based on the calculated values of the independent variables of all sub-samples in the same type of fine-grained soil sample under each assumed value and the first quantitative relationship, the theoretical straight line of the permeability coefficient of the corresponding fine-grained soil sample under the corresponding assumed value is determined. Based on the theoretical straight line of the permeability coefficient of each fine-grained soil sample under each assumed value and the permeability coefficient data of all sub-samples of the corresponding fine-grained soil sample, the permeability characterization data of the corresponding fine-grained soil sample are determined.
6. The method according to claim 1, characterized in that, The determination of plasticity index data for various fine-grained soil samples in S2 specifically includes: Liquid limit and plastic limit tests were conducted on various fine-grained soil samples to obtain plasticity index data for each sample.
7. The method according to claim 1, characterized in that, The second quantitative relationship between the plasticity index and permeability characterization parameters of fine-grained soil, constructed in step S2 based on the plasticity index data and the permeability characterization data, specifically includes: The plasticity index data and the permeability characterization data are subjected to nonlinear fitting to obtain a second quantitative relationship between the plasticity index and permeability characterization parameters of fine-grained soil. The second quantitative relationship is a power function.
8. The method according to claim 1, characterized in that, The pore parameters include porosity, the number of pores in each cross section of the fine-grained soil, and the diameter of each pore.