Inversion method, system, equipment and medium for total water content of salinized soil

Abstract

The invention provides an inversion method, system, equipment and medium for the total water content of salinized soil, and belongs to the field of freeze thawing monitoring of salinized soil, and the method comprises the steps: firstly obtaining the dielectric constant # imgabs0 #, the conductivity # imgabs1 #, the real-time temperature T and the initial water content # imgabs2 # of target salinized soil; the soluble salt content P is calculated through conductivity, and the freezing temperature is determined by combining the initial water content. When the real-time temperature T is higher than the freezing temperature, calculating the content of unfrozen water by using # imgabs3 and # imgabs4; when T is lower than the freezing temperature, the corrected salt concentration of the unfrozen water is calculated through the conductivity, then the unfrozen water amount is calculated in combination with # imgabs5 #, then the frozen water amount is obtained according to the difference value of the initial water content and the unfrozen water amount, the freezing rate is determined according to the ratio of the frozen water amount to the initial water content, and the freezing rate is determined according to the freezing rate. And finally, realizing quantitative analysis of moisture distribution in the freezing and thawing process of the salinized soil by utilizing the freezing rate. According to the method, the technical problem that the frozen water quantity of the frozen saline soil cannot be directly measured is solved, and accurate calculation of unfrozen water and frozen water at any temperature is realized.

Description

Technical Field

[0001] The present invention belongs to the field of saline soil freeze-thaw monitoring, and in particular relates to an inversion method, system, equipment and medium for total water content of saline soil. Background Art

[0002] Currently, methods for measuring the unfrozen water content and ice content in frozen soil primarily include gas expansion, nuclear magnetic resonance (NMR), thermometry, frequency domain reflectometry (FDR), and time domain reflectometry (TDR). The gas expansion method estimates the unfrozen water content by measuring the volume change of a frozen soil sample in a sealed container. As frozen soil thaws, ice converts to water, causing a volume contraction. The volume difference is calculated using the pressure change of a gas (such as helium), indirectly determining the ice content and unfrozen water content. This method requires destructive sampling and cannot be used for in situ measurements. Furthermore, the method is complex and requires high airtightness from the equipment, with even small leaks resulting in significant errors. It is only suitable for laboratory environments and cannot monitor dynamic processes in real time.

[0003] Nuclear magnetic resonance (NMR) distinguishes liquid water from ice by using the difference in the relaxation time of hydrogen nuclei (¹H) in a magnetic field. Unfrozen water molecules are in active motion and have a short relaxation time, while ice molecules are immobile and have a long relaxation time. The ratio of the two is calculated based on signal intensity. However, the equipment is expensive and bulky, making it difficult to use for field measurements. Salt or impurities in frozen soil can also interfere with the signal, causing errors. Instrument stability may decrease in low temperatures, requiring precise temperature control.

[0004] The thermometry method is based on the latent heat release and absorption during phase transitions in frozen soil. By monitoring temperature curves (such as the temperature plateau caused by the latent heat released by water freezing during cooling), combined with thermodynamic models, the unfrozen water content is calculated. However, this method relies on precise temperature sensors and a uniform temperature field. The complex temperature gradients in actual frozen soil can easily introduce errors. Furthermore, it can only indirectly estimate the unfrozen water content and cannot directly distinguish the ice-water ratio. The frequency domain reflectometry method estimates the unfrozen water content by measuring the dielectric constant of frozen soil (which is related to the water content).

[0005] When high-frequency electromagnetic waves propagate through a medium, the dielectric constant varies with the unfrozen water content. A calibration model is established using the frequency response of the reflected signal. However, this method requires frequent calibration because the dielectric constant is affected by multiple factors, such as soil texture, salinity, and temperature. The presence of ice significantly alters the dielectric properties, and the nonlinear response of ice-water mixtures can also lead to model deviations.

[0006] Time-domain reflectometry, similar to FDR, calculates the dielectric constant based on the propagation time of electromagnetic waves. The propagation time of the pulse signal between the probes is related to the dielectric constant, which is converted to the unfrozen water content using an empirical formula. This method exhibits minimal differences in the dielectric properties of ice and unfrozen water in frozen soil, resulting in low sensitivity. Pre-calibration for soil texture, pore structure, and salinity is required, limiting its general applicability.

[0007] Existing technologies rely on frequency domain reflectometry (FDR) and time domain reflectometry (TDR) to measure dielectric constant and conductivity, and indirectly infer unfrozen water content through empirical models. However, these methods have significant limitations: First, existing models can only invert unfrozen water content, while the calculation of total water content relies on the sum of ice content and unfrozen water content. However, in actual freezing environments, direct measurement of ice content is difficult to achieve due to technical limitations. Second, salt concentration in saline soils undergoes dynamic migration with changes in water phase. Traditional models do not consider the dynamic characteristics of salt solution concentration, resulting in a sharp decrease in measurement accuracy under salt crystallization conditions. Third, existing technologies are not compatible with the effective application of water-salt sensors (such as 5TE) in negative temperature environments. Their unfrozen water measurements are prone to distortion errors during the freezing phase, seriously restricting the applicability of these devices in cold-region projects. Summary of the Invention

[0008] In order to solve the problem of accurate calculation of unfrozen water and frozen water at any temperature, the present invention provides an inversion method, system, equipment and medium for total water content of saline soil.

[0009] In order to achieve the above object, the present invention provides the following technical solutions, including: Obtain the dielectric constant of the target saline soil , conductivity , real-time temperature T and initial water content .

[0010] Through conductivity Calculate the soluble salt content of the target saline soil P ; According to soluble salt content P and initial water content Determining the freezing temperature .

[0011] When the real-time temperature T Above freezing temperature When the dielectric constant of the target saline soil is used and conductivity Calculate unfrozen water content ; When the real-time temperature is lower than the freezing temperature When using conductivity Calculate the corrected unfrozen water salt concentration , using the dielectric constant and the unfrozen water salt concentration Calculate the amount of unfrozen water . From the initial water content and unfrozen water Calculate the amount of frozen water , by the amount of frozen water and initial water content The ratio of the freezing rate ;

[0012] Utilize the freeze rate Quantitative analysis of water distribution in saline soil during freeze-thaw.

[0013] Preferably, the soluble salt content P and initial water content Determining the freezing temperature ,include: The target saline soil is converted into saline soil aqueous solution, and the number of salt molecule particles in the saline soil aqueous solution is obtained respectively. n、 Density of saline soil water solution mass , the molar mass of saline soil aqueous solution M ; The expression is as follows: ; (1) In formula (1), The freezing temperature constant of pure water , temperature constant of saturated salt-free soil and the universal gas constant R Calculated.

[0014] Preferably, the real-time temperature T Above freezing temperature When the dielectric constant of the target saline soil is used and conductivity Calculate unfrozen water content , The expression is: ; (2) In formula (2), 、 、 is the fitting coefficient.

[0015] Preferably, when the real-time temperature is less than the freezing temperature When using conductivity Calculate the corrected unfrozen water salt concentration ,include: By conductivity , real-time temperature T and reference temperature Calculated Conductivity under ; pass and Establishing ionic strength Relationship, among which , The concentrations of saline soil aqueous solution at the initial state and at any time of the target saline soil are The ionic strength, G are electrical parameters, Initial ionic strength, is saturation; is the saturation index; is the coefficient; (3) = (4) (5) ; (6) Combining equations (3), (4) and (5), we can calculate the ionic strength in the pore solution of saline soil: , calculated by formula (6) .

[0016] Preferably, the dielectric constant and unfrozen water salt concentration Calculate the amount of unfrozen water , The expression is: ; (7) In formula (7), 、 、 、 is the fitting coefficient.

[0017] Preferably, the initial water content and unfrozen water Calculate the amount of frozen water , by the amount of frozen water and initial water content The ratio of the freezing rate , and The expressions are shown in (8) and (9).

[0018] ; (8) (9) The present invention also provides an inversion system for total water content of saline soil, comprising: Data acquisition module, used to obtain the dielectric constant of the target saline soil , conductivity , real-time temperature T and initial water content .

[0019] Freeze temperature calculation module for conductivity Calculate the soluble salt content of the target saline soil P ; According to soluble salt content P and initial water content Determining the freezing temperature .

[0020] Moisture content calculation module, used when real-time temperature T Above freezing temperature When the dielectric constant of the target saline soil is used and conductivity Calculate unfrozen water content ; When the real-time temperature is lower than the freezing temperature When using conductivity Calculate the corrected unfrozen water salt concentration , using the dielectric constant and the unfrozen water salt concentration Calculate the amount of unfrozen water ; From the initial water content and unfrozen water Calculate the amount of frozen water , by the amount of frozen water and initial water content The ratio of the freezing rate .

[0021] Freeze rate application module, used to utilize freeze rate Quantitative analysis of water distribution in saline soil during freeze-thaw.

[0022] The present invention also provides a computer device, comprising a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement any one of the steps in the inversion method for the total moisture content of saline soil.

[0023] The present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is loaded by a processor, it can execute any one of the steps in the inversion method for the total moisture content of saline soil.

[0024] The inversion method for total water content of saline soil provided by the present invention has the following beneficial effects: The present invention breaks the static assumption of the traditional empirical model, introduces the dynamic migration mechanism of salt solution concentration and freezing rate parameters, and constructs a multi-physics field coupling model of dielectric constant, conductivity and total water content to calculate the unfrozen water content. and frozen water volume , which solves the technical problem that the ice content in frozen saline soil cannot be directly measured; by establishing a freezing rate and conductivity correction function, it can achieve accurate calculation of unfrozen water and frozen water at any temperature. The technical solution is different from the existing single dielectric constant inversion method. It only requires a universal water-salt sensor to obtain the dielectric constant of the target saline soil. , conductivity , real-time temperature T and initial water content , no additional equipment is required, significantly reducing the monitoring cost of cold region projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] To more clearly illustrate the embodiments of the present invention and its design, the following briefly introduces the drawings required for this embodiment. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0026] Figure 1 This is a flow chart of a method for inverting the total water content of saline soil according to an embodiment of the present invention; Figure 2 The relationship between the initial water content and the freezing temperature of the embodiment of the present invention; Figure 3 This is a graph showing the relationship between ice content and temperature under different water and salt content conditions according to an embodiment of the present invention; Figure 4 This is a comparison chart for accuracy verification of an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solution of the present invention and to be able to implement it, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention.

[0028] The present invention provides a method for inverting the total water content of saline soil, specifically Figure 1 Shown, including: S1. Obtain the dielectric constant of the target saline soil , conductivity , real-time temperature T and initial water content .

[0029] S2, through conductivity Calculate the soluble salt content of the target saline soil P ; According to soluble salt content P and initial water content Determining the freezing temperature .

[0030] The conductivity measured by the sensor is used to calculate the soluble salt content in the saline soil. The freezing temperature is then determined based on the soluble salt content, and this information is used to determine whether the saline soil has undergone a water-to-ice phase transition. The temperature at which the water-to-ice phase transition occurs during the freezing process is called the freezing temperature. The relationship between the freezing temperature, water content, and salt content is as follows:

[0031] ; (1) In formula (1), is the freezing temperature of saturated salt-free soil ( K ); is the freezing temperature of soil ( K ); R is the universal gas constant (R = 8.31 (J / (mol·K))); η is the constant in the generalized Clapeyron equation (1.23 MPa / °C); n is the number of particles (molecules or ions) produced by one salt molecule in the solution; is the density of the liquid solution mass (kg / m3); P is the soluble salt content (kg / kg); M is the molar mass of the solute (kg / mol); is the initial moisture content (kg / kg); is the temperature reduction coefficient (K·m3 / mol); is the concentration of salt solution in unfrozen water (mol / L).

[0032] The effective molar concentration of ions in the non-ideal dilute solution in saline soil (mol / L) is: ; (2) ; (3) In formula (3), k is the effective molar concentration correction factor (mol / L); is the molar concentration of the initial solution (ion) (mol / m3); is the freezing temperature of pure water (273.15K).

[0033] Arranging formulas (1) and (3) yields: ; (4) By reorganizing the formula, we can get the freezing temperature expression of different initial moisture contents: ; (5) ; (6) In formula (5) As shown in formula (6), is the influence coefficient of soluble salt content.

[0034] S3, when the real-time temperature T Above freezing temperature When the dielectric constant of the target saline soil is used and conductivity Calculate unfrozen water content ; When the real-time temperature is lower than the freezing temperature When using conductivity Calculate the corrected unfrozen water salt concentration , using the dielectric constant and the unfrozen water salt concentration Calculate the amount of unfrozen water ; From the initial water content and unfrozen water Calculate the amount of frozen water , by the amount of frozen water and initial water content The ratio of the freezing rate .

[0035] When the temperature is above the freezing point, the total water content of saline soil is equal to the unfrozen water content. This method uses a temperature measurement method to calculate the unfrozen water content and fits it with a proposed theoretical formula to determine the various parameter values ​​for calculating the unfrozen water content based on dielectric properties. This method posits that the relationship between the unfrozen water content and temperature during the freezing process of saline soil is:

[0036] ; (7) In formula (7), Indicates the unfrozen water content in saline soil (kg / kg); T is the measured temperature (K); is an empirical parameter; are empirical parameters; their values ​​are generally affected by soil quality, salinity of saline soil, etc. Using the relationship between freezing temperature and initial moisture content, draw a straight line with the absolute value of freezing temperature as the horizontal axis and the initial moisture content as the vertical axis, as shown in the figure below: Figure 2 By transforming the two sets of data points of freezing temperature and initial moisture content, the formula was derived, and finally an expression containing only the parameter q was obtained:

[0037] ; (8) In formula (8), Indicates the unfrozen water content in saline soil (kg / kg); is the initial moisture content (kg / kg); is the freezing temperature of soil ( K ); T is the measured temperature ( K ); is an empirical parameter; is an empirical parameter; According to two different initial water contents and their corresponding freezing temperatures, the empirical parameters can be calculated separately and , thus determining the relationship between unfrozen water content and temperature, namely: ; (9) ; (10) In formula (9), 、 represents the initial water content in two different saline soils (kg / kg); 、 is the freezing temperature of two different soils ( K ); T is the measured temperature ( K ); is an empirical parameter; is an empirical parameter.

[0038] In order to improve the accuracy of formula (8), the present invention performs a pairwise analysis of n groups of initial water contents and their corresponding freezing temperatures in the experimental design under the same salinity conditions, as shown in formula (11). Specifically, for each group of water content and freezing temperature, its parameters are calculated separately. p and q The results were evaluated by the mean absolute error (MAE) and mean relative error (MRE). Under the same salinity condition, the present invention selected five groups of different water contents and their corresponding freezing temperatures for combined analysis, namely, As shown in Table 1, it can be seen from Table 1 that when the initial moisture content is 8% and 16%, the calculated parameters p and q The results showed the smallest mean absolute error and mean relative error, which were 0.0025 and 0.339, respectively. Finally, the optimal parameters were selected for quantitative analysis of the relationship between unfrozen water content and temperature.

[0039] ; (11) The mean absolute error is: ; (12) In formula (12): is the initial moisture content (kg / kg); Indicates the unfrozen water content in saline soil (kg / kg).

[0040] The relative absolute error is: ; (13) In formula (13), is the initial moisture content (kg / kg); Indicates the unfrozen water content in saline soil (kg / kg).

[0041] Table 1 Soil samples with different initial water contents and a salt content of 0.84% p 、 q Parameter calculation results When the temperature is below or equal to the freezing point, the mass of ice is further calculated using the freezing rate and unfrozen water content. Changes in soil moisture are primarily manifested as changes in the dielectric constant with temperature. Salt concentration significantly affects its conductivity and the accuracy of FDR sensors. This paper comprehensively considers the effects of salt content and moisture content on soil dielectric constant and conductivity, and proposes a moisture model based on dielectric constant and conductivity, namely:

[0042] ; (14) In formula (14), Indicates the unfrozen water content in saline soil (kg / kg); 、 、 , are fitting coefficients; is the conductivity; is the dielectric constant.

[0043] During the freezing process of saline soil, when the temperature reaches the freezing point, its dielectric constant and conductivity will change significantly. However, soil conductivity is not only affected by temperature and salt concentration, but is also closely related to the conductive paths within the frozen soil. In order to accurately describe the impact of salt concentration and temperature on the unfrozen water content, this paper adopts a model for calculating the unfrozen water content based on the initial salt concentration and dielectric constant, namely:

[0044] ; (15) In formula (15), is the unfrozen water content (kg / kg); 、 、 、 is the fitting coefficient; is the conductivity; is the dielectric constant; is the salt solution concentration in the unfrozen water (mol / L). Formula (15) calculates the specific parameters of the unfrozen water content based on the dielectric constant of saline soil and the soluble salt content in the unfrozen water. As shown in Table 2, the coefficient of determination (R2) of this formula is 0.9499, which is greater than 0.8500, indicating that the formula has a good fitting effect.

[0045] Table 2 Unfrozen water content formula coefficients During the freezing process of saline soil, the concentration of the solution in the unfrozen water increases as its content decreases. When the concentration of soluble salts in the unfrozen water exceeds its maximum saturation solubility, salt crystallization occurs, reducing the soluble salt content. Therefore, to more accurately describe the changes in salt solution concentration in unfrozen water at different temperatures, the present invention derives a relationship between soil conductivity and initial soil conductivity based on the changes in pore solution conductivity:

[0046] (16) In formula (16), and Temperature and , the pore concentration is Soil conductivity and pore water conductivity; is the slope of conductivity changing with temperature (when the reference temperature is When the temperature is 20℃, ); is saturation; is the saturation index (n=2); are electrical parameters ( ).

[0047] The expression is: (17) = (18) ; (19) In formula (18), and Temperature and ; pore concentration is Soil conductivity and pore water conductivity; is saturation; is the saturation index (n=2); is the slope of conductivity changing with temperature (when the reference temperature is When the temperature is 20℃, ); , The concentration of the solution at the initial state and at any time is The ionic strength; represents the square of the ionic charge; are electrical parameters ( ).

[0048] By combining equations (17) and (18), we can calculate the ionic strength of the pore solution. Based on the specific type and type of salt in the pore solution, we can deduce the salt concentration in the unfrozen water using equation (19). This concentration value can be further combined with equations to determine the unfrozen water content at different temperatures.

[0049] Calculation of ice content: During the freezing process of saline soil, free water in the soil transforms into ice. If we ignore the influence of external factors such as evaporation from the soil surface, we can assume that the soil follows the law of conservation of mass during freezing, meaning that the total mass of water in the soil remains constant. Therefore, the ice content of saline soil during freezing can be calculated using the unfrozen water content, namely:

[0050] ; (20) In formula (20), is the initial moisture content (kg / kg); Indicates the unfrozen water content in saline soil (kg / kg).

[0051] According to the unfrozen water content determined by the dielectric constant and the soluble salt content in unfrozen water at different temperatures, combined with formula (20), the relationship between the mass content of ice and temperature under different water content and salt content conditions can be obtained, as follows: Figure 3 As shown in Figure 1, ice content is a key indicator for evaluating the degree of ice formation in saline soil during freezing. Therefore, the present invention introduces the parameter of freezing rate to quantitatively describe the freezing ratio of the initial water content of saline soil under freeze-thaw conditions. Based on the relationship between the mass content of ice and temperature under different water and salt content conditions, the relationship between the freezing rate of ice in saline soil and temperature can be derived, namely:

[0052] ; (twenty one) In formula (21), T is the measured temperature (K).

[0053] The freezing rate is defined as the percentage of the ratio of the mass content of ice in saline soil to the total water content (initial water content), that is: ; (twenty two) In formula (22), is the initial moisture content (kg / kg); Indicates the unfrozen water content in saline soil (kg / kg); is the ice content (kg / kg).

[0054] According to formulas (20) and (22), the mass content of ice at different temperatures can be expressed as: ; (twenty three) In formula (23), is the mass content of ice (kg / kg), is the freezing rate (%); Indicates the unfrozen water content in saline soil (kg / kg); T is the measured temperature (K).

[0055] During the freezing process of saline soil, the total water content consists of unfrozen water and ice. The form of water present is primarily influenced by temperature and initial mass fraction. When the temperature of saline soil is above the freezing point, the total water content is entirely unfrozen water, equivalent to the initial water content. When the temperature drops below the freezing point, the liquid water in the soil begins to gradually transform into ice. However, due to the effects of surface energy, a certain amount of unfrozen water will still remain in the soil at extremely low temperatures. Therefore, the total water content in saline soil can be expressed as:

[0056] ; (twenty four) In formula (24), is the initial moisture content (kg / kg); Indicates the unfrozen water content in saline soil (kg / kg); is the ice content (kg / kg); T is the measured temperature ( K ); is the freezing temperature of soil ( K） .

[0057] S4. Utilization freezing rate Quantitative analysis of water distribution in saline soil during freeze-thaw.

[0058] To verify the accuracy of the proposed method, this paper refers to existing research methods that use the freezing temperature of saline soil to calculate the unfrozen water content and ice content at different temperatures, as well as methods that calculate the water content of saline soil using the dielectric constant. Subsequently, this paper applies the experimental data to these models for calculation and compares them with the model established in this paper. The specific results are as follows: Figure 4 As shown, from Figure 4As can be seen from the data, the calculation method proposed in this paper is consistent with the overall trends of existing research results. Under the same temperature conditions, the difference between the unfrozen water content and the ice content is extremely small, and the relative errors of the two models are both within 2%, demonstrating high accuracy. This shows that the model established in this paper can accurately invert the total water content, including the unfrozen water content and ice content, in saline soil during the freeze-thaw process.

[0059] Based on the same inventive concept, the present invention also provides a method system for inverting the total moisture content of saline soil, comprising: Data acquisition module, used to obtain the dielectric constant of the target saline soil , conductivity , real-time temperature T and initial water content .

[0060] Freeze temperature calculation module for conductivity Calculate the soluble salt content of the target saline soil P ; According to soluble salt content P and initial water content Determining the freezing temperature .

[0061] Moisture content calculation module, used when real-time temperature T Above freezing temperature When the dielectric constant of the target saline soil is used and conductivity Calculate unfrozen water content ; When the real-time temperature is lower than the freezing temperature When using conductivity Calculate the corrected unfrozen water salt concentration , using the dielectric constant and the unfrozen water salt concentration Calculate the amount of unfrozen water ; From the initial water content and unfrozen water Calculate the amount of frozen water , by the amount of frozen water and initial water content The ratio of the freezing rate .

[0062] Freeze rate application module, used to utilize freeze rate Quantitative analysis of water distribution in saline soil during freeze-thaw.

[0063] The present invention also provides a computer device. At the hardware level, the computer device includes a processor, an internal bus, a network interface, memory, and non-volatile storage, and may also include other hardware required for operations. The processor reads a corresponding computer program from the non-volatile storage into the internal memory and then executes it to implement the above-mentioned method for inverting the total moisture content of saline soil.

[0064] The present invention also provides a computer-readable storage medium, which stores a computer program. The computer program can be used to execute the inversion method for the total water content of saline soil provided above.

[0065] The specific limitations of the calculation system for the inversion method of the total moisture content of saline soil can be found in the limitations of the inversion method for the total moisture content of saline soil described above and will not be repeated here. Each module in the above-mentioned inversion system for the total moisture content of saline soil can be implemented in whole or in part through software, hardware, or a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in hardware form, or can be stored in a memory in a computer device in software form, so that the processor can call and execute the corresponding operations of each of the above modules.

[0066] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. In addition, the above-mentioned embodiments only express several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of this application, several variations and improvements can be made, which all fall within the scope of protection of this application. Therefore, the scope of protection of the patent in this application shall be based on the attached claims.

Claims

1. A method for inverting the total water content of saline soil, characterized in that: The method comprises: Obtain the dielectric constant of the target saline soil , conductivity , real-time temperature T and initial water content ; Through conductivity Calculate the soluble salt content of the target saline soil P ; According to soluble salt content P and initial water content Determining the freezing temperature ; When the real-time temperature T Above freezing temperature When the dielectric constant of the target saline soil is used and conductivity Calculate unfrozen water content ; When the real-time temperature is lower than the freezing temperature When using conductivity Calculate the corrected unfrozen water salt concentration , using the dielectric constant and the unfrozen water salt concentration Calculate the amount of unfrozen water ; From the initial water content and unfrozen water Calculate the amount of frozen water , by the amount of frozen water and initial water content The ratio of the freezing rate ; Utilize the freeze rate Quantitative analysis of water distribution in saline soil during freeze-thaw.

2. The inversion method for total water content of saline soil according to claim 1, characterized in that: The soluble salt content P and initial water content Determining the freezing temperature ,include: The target saline soil is converted into saline soil aqueous solution, and the number of salt molecule particles in the saline soil aqueous solution is obtained respectively. n、 Density of saline soil water solution mass , the molar mass of saline soil aqueous solution M ; The expression is as follows: ； （1） In formula (1), The freezing temperature constant of pure water , temperature constant of saturated salt-free soil and the universal gas constant R Calculated.

3. The inversion method for total water content of saline soil according to claim 1, characterized in that: When the real-time temperature T Above freezing temperature When the dielectric constant of the target saline soil is used and conductivity Calculate unfrozen water content , The expression is: ； （2） In formula (2), 、 、 is the fitting coefficient.

4. The inversion method for total water content of saline soil according to claim 1, characterized in that: When the real-time temperature is lower than the freezing temperature When using conductivity Calculate the corrected unfrozen water salt concentration ,include: By conductivity , real-time temperature T and reference temperature Calculated Conductivity under ; pass and Establishing ionic strength Relationship, among which , The concentrations of saline soil aqueous solution at the initial state and at any time of the target saline soil are The ionic strength, G are electrical parameters, Initial ionic strength, is saturation; is the saturation index; is the coefficient; （3） = （4） （5） ； （6） Combining equations (3), (4) and (5), we can calculate the ionic strength in the pore solution of saline soil: , calculated by formula (6) .

5. The inversion method for total water content of saline soil according to claim 1, characterized in that: The dielectric constant and unfrozen water salt concentration Calculate the amount of unfrozen water , The expression is: ； （7） In formula (7), 、 、 、 is the fitting coefficient.

6. The inversion method for total water content of saline soil according to claim 1, characterized in that: The initial water content and unfrozen water Calculate the amount of frozen water , by the amount of frozen water and initial water content The ratio of the freezing rate , and The expressions are shown in (8) and (9).

7. ； （8） （9） An inversion system for total water content of saline soil, characterized in that: include: Data acquisition module, used to obtain the dielectric constant of the target saline soil , conductivity , real-time temperature T and initial water content ; Freeze temperature calculation module for conductivity Calculate the soluble salt content of the target saline soil P ; According to soluble salt content P and initial water content Determining the freezing temperature ; Moisture content calculation module, used when real-time temperature T Above freezing temperature When the dielectric constant of the target saline soil is used and conductivity Calculate unfrozen water content ; When the real-time temperature is lower than the freezing temperature When using conductivity Calculate the corrected unfrozen water salt concentration , using the dielectric constant and the unfrozen water salt concentration Calculate the amount of unfrozen water ; From the initial water content and unfrozen water Calculate the amount of frozen water , by the amount of frozen water and initial water content The ratio of the freezing rate ; Freeze rate application module, used to utilize freeze rate Quantitative analysis of water distribution in saline soil during freeze-thaw.

8. A computer device, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the method steps according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method steps according to any one of claims 1 to 6 are implemented.

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