A method for optimizing the number of times solid-phase stabilization materials and contaminated soil are mixed

Abstract

The present invention belongs to the field of heavy metal contaminated soil stabilization and remediation, and specifically relates to a method for optimizing the number of times solid-phase stabilization materials and contaminated soil are mixed, using solid-phase stabilization materials and specific elements in contaminated soil as detection indicators; constructing a solid-phase stabilization material and contaminated soil mixing degree measurement model through the content of the detection indicators after different mixing times; constructing a unit energy consumption mixing degree model based on the mixing degree and energy consumption, and then obtaining the unit energy consumption mixing degree of different mixing times; the mixing number corresponding to the maximum value of the unit energy consumption mixing degree is the optimized mixing number for the contaminated soil mixing stabilization treatment. The present invention is aimed at the stabilization and remediation of heavy metal contaminated soil, considering the heterogeneity of both solid-phase stabilization materials and heavy metals in the soil during the mixing process, constructing a mixing degree measurement model based on the coefficient of variation of two variables, taking into account the relationship between the mixing number and energy consumption, and optimizing the mixing number of solid-phase stabilization materials and contaminated soil.

Description

Technical Field

[0001] The invention belongs to the field of heavy metal contaminated soil stabilization and restoration, and specifically relates to a method for optimizing the number of times a solid phase stabilization material and contaminated soil are mixed. Background Art

[0002] Heavy metals are a typical toxic and harmful pollutant. Due to their accumulation, stability and persistence in the soil, they will cause a series of ecological and environmental problems. In recent years, soil heavy metal pollution has been increasingly valued by countries around the world. Stabilization has been widely used in actual remediation projects due to its simple principles and convenient operation. According to the statistics of the 16th edition of the Superfund Remedy Report released by the EPA in 2020, stabilization technology was used in 478 of the 2,633 contaminated site remediation projects between 1982 and 2017. In addition, in actual projects, due to the constraints of economic costs and construction schedules, the number of mixing times for stabilization and remediation of heavy metal contaminated soil is determined. The degree of mixing of stabilization materials and contaminated soil is not considered. Therefore, measuring the degree of mixing of stabilization materials and contaminated soil is the premise and basis for optimizing the number of mixing times of solid phase stabilization materials and contaminated soil.

[0003] For solid-phase stabilized materials (blending materials) and heavy metal-contaminated soils (blended materials), there are many methods for evaluating the degree of homogeneity of solid-phase materials after blending. The research and development ideas of this type of technology are (1) assuming that the blending and blended solid-phase materials are different and that there is no heterogeneity between the two (202210668363.7); (2) detecting specific components of the blended solid-phase materials, and the detection is usually a rapid test (202111463989.6); (3) calculating the coefficient of variation of the detected components, and determining the degree of homogeneity between the materials by the size of the coefficient of variation (202210926447.6).

[0004] However, this type of technology is not suitable for measuring the degree of mixing of solid-phase stabilization materials with contaminated soil. This is because (1) in the stabilization and remediation of contaminated soil, the purpose of mixing solid-phase stabilization materials (blending materials) and contaminated soil (blended materials) is to ensure sufficient contact and reaction between heavy metals in the soil and stabilization materials; (2) however, there is a large heterogeneity in the heavy metals in the contaminated soil (blended materials). Therefore, only detecting and analyzing the coefficient of variation of the stabilization material (blending material) cannot meet the stabilization requirements; (3) the range of the coefficient of variation is a non-negative rational number, which cannot uniformly measure the degree of mixing of different materials, and is not convenient for measuring the degree of mixing of solid-phase stabilization materials and contaminated soil in actual engineering.

[0005] In addition, as the number of times the solid-phase stabilization material and the contaminated soil are mixed increases, the mixing of the two becomes more uniform. However, as the number of times the mixing increases, the energy consumption or cost also increases accordingly. The relationship between mixing uniformity and energy consumption cannot be simply judged. How to balance the mixing degree and energy consumption is the key to optimizing the number of times the solid-phase stabilization material and the contaminated soil are mixed. In summary, it is necessary to establish a method for optimizing the number of times the mixing is mixed based on the measurement of the mixing degree. Summary of the invention

[0006] The present invention aims to provide a method for optimizing the number of times a solid phase stabilization material and contaminated soil are mixed evenly.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is:

[0008] A method for optimizing the number of times solid-phase stabilization materials and contaminated soil are mixed evenly.

[0009] (1) Using solid-phase stabilized materials and specific elements in contaminated soil as detection indicators;

[0010] (2) Constructing a measurement model for the degree of mixing of solid-phase stabilization materials and contaminated soil by measuring the contents of the above-mentioned detection indicators after different mixing times;

[0011] (3) constructing a unit energy consumption mixing degree model based on the mixing degree and energy consumption obtained in step (2), and then obtaining the unit energy consumption mixing degree of different mixing times;

[0012] (4) The number of mixing times corresponding to the maximum mixing degree per unit energy consumption is the optimized number of mixing times for the mixing stabilization treatment of contaminated soil.

[0013] The step (2) comprises mixing the solid-phase stabilization material and the contaminated soil, and determining the content of the detection index under different mixing times; obtaining the bivariate coefficient of variation after mixing by the degree of difference in the content of the detection index after different mixing times; the calculation indicators of the degree of difference are the mean value and the standard deviation; and constructing a solid-phase stabilization material and contaminated soil mixing degree measurement model based on the bivariate coefficient of variation, which is used to measure the mixing degree corresponding to different mixing times.

[0014] The step (1) is:

[0015] 1) The solid phase stabilization material is used as the blending material (A) and the contaminated soil is used as the blended material (B);

[0016] 2) Compare the content of Fe, Ca, S and P in the blended material (A) A and the content C in the blended material (B) B , select C A / C BThe element with the largest ratio is used as the detection index (IndexA) of the blended material (A);

[0017] 3) Selecting the heavy metal to be stabilized as the detection index (IndexB) of the blended material (B).

[0018] Step (2) Determine the content of the detection index under different mixing times:

[0019] 1) The solid phase stabilization material and the contaminated soil are mixed for n times;

[0020] 2) Divide the mixed material into m portions as samples to be tested;

[0021] 3) Determine the content of the detection indexes IndexA and IndexB respectively. ij and b ij , i=1,2,…n; j=1,2,…m;

[0022] 4) Select a ij The maximum value is normalized to obtain the detection index IndexA content as A ij ;

[0023] 5) Select b ij The maximum value is normalized to obtain the detection index IndexB content B ij .

[0024] Step (2) constructs the coefficient of variation of the bivariate after mixing:

[0025] 1) The average values ​​of the contents of the detection indexes IndexA and IndexB after the i-th mixing are μ Ai and μ Bi , i=1,2,…n,j=1,2,…m, the calculation formula is as follows;

[0026]

[0027]

[0028] 2) The standard deviations of the contents of the detection indexes IndexA and IndexB after the i-th mixing are δ Ai and δ Bi , i=1,2,…n,j=1,2,…m, the calculation formula is as follows;

[0029]

[0030]

[0031] 3) The coefficient of variation (CV) of the two variables of the content of IndexA and IndexB detected after the i-th mixing i , i=1,2,…n,j=1,2,…m, the calculation formula is as follows;

[0032]

[0033] Step (2) constructs a measurement model of the degree of mixing of solid phase stabilization materials and contaminated soil based on the bivariate coefficient of variation:

[0034] 1) Construct a relationship model between the number of equal mixing times and the corresponding bivariate coefficient of variation;

[0035]

[0036] In the formula: x is the number of times of mixing; y is the coefficient of variation of the two variables; a, b and c are fitting parameters;

[0037] 2) The above model is converted into a mixing degree equation. By normalization, the mixing degree corresponding to the maximum mixing number N is converted to 1, and a standardized mixing degree measurement model is constructed:

[0038]

[0039] Wherein: x is the number of uniform mixing, x = 1, 2, ... N; U is the uniform mixing degree; N is the maximum number of uniform mixing; a, b and c are the fitting parameters of formula (6).

[0040] The energy consumption of different mixing times is measured by mechanical energy consumption, and the calculation formula is as follows;

[0041]

[0042] Where: E i is the energy consumption of the ith mixing (yuan / m 3 ); F is the diesel consumption per cubic meter of contaminated soil (L / m 3 ); P is the unit price of diesel (yuan / L).

[0043] Step (3) constructs a unit energy consumption mixing degree model based on the mixing degree and energy consumption.

[0044]

[0045] Where: EU i is the unit energy consumption of the ith mixing (m3 / yuan); U i is the mixing degree of formula (7); E i is the energy consumption of formula (8).

[0046] The maximum mixing times are calculated as follows:

[0047]

[0048] Wherein: △y is the absolute value of the difference in the coefficient of variation of the two variables between two consecutive equal mixing times; when △y<5%, the maximum equal mixing times N=i+1.

[0049] The present invention has the following advantages and beneficial effects:

[0050] The present invention aims at the stabilization and remediation of heavy metal contaminated soil. Taking into account the heterogeneity of both solid-phase stabilization materials and heavy metals in the soil during the mixing process, the present invention constructs a mixing degree measurement model based on the bivariate coefficient of variation, which is used to measure the mixing degrees corresponding to different mixing times. At the same time, the relationship between the mixing times and energy consumption is taken into account, and the mixing times of the solid-phase stabilization materials and the contaminated soil are optimized to guide the implementation of heavy metal contaminated soil stabilization and remediation projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 The present invention provides a flowchart for constructing a uniform mixing degree measurement model according to an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The specific implementation modes of the present invention are further described below in conjunction with examples. It should be noted that the specific implementation modes described here are only for illustrating and explaining the present invention, and are not limited to the present invention.

[0053] A method for optimizing the number of times solid-phase stabilization materials and contaminated soil are mixed evenly.

[0054] (1) Using solid-phase stabilized materials and specific elements in contaminated soil as detection indicators;

[0055] (2) Constructing a measurement model for the degree of mixing of solid-phase stabilization materials and contaminated soil by measuring the contents of the above-mentioned detection indicators after different mixing times;

[0056] (3) constructing a unit energy consumption mixing degree model based on the mixing degree and energy consumption obtained in step (2), and then obtaining the unit energy consumption mixing degree of different mixing times;

[0057] (4) The number of mixing times corresponding to the maximum mixing degree per unit energy consumption is the optimized number of mixing times for the mixing and stabilization of contaminated soil, which is used to guide the engineering construction of mixing and stabilization.

[0058] The step (2) comprises mixing the solid-phase stabilization material and the contaminated soil, and determining the content of the detection index under different mixing times; obtaining the bivariate coefficient of variation after mixing by the degree of difference in the content of the detection index after different mixing times; the difference degree calculation indicators are the mean value and the standard deviation; and constructing a solid-phase stabilization material and contaminated soil mixing degree measurement model based on the bivariate coefficient of variation, which is used to measure the mixing degree corresponding to different mixing times.

[0059] The step (1) is:

[0060] 1) The solid phase stabilization material is used as the blending material (A) and the contaminated soil is used as the blended material (B);

[0061] 2) Compare the content of Fe, Ca, S and P in the blended material (A) A and the content C in the blended material (B) B , select C A / C B The element with the largest ratio is used as the detection index (IndexA) of the blended material (A);

[0062] 3) Selecting the heavy metal to be stabilized as the detection index (IndexB) of the blended material (B).

[0063] Step (2) Determine the content of the detection index under different mixing times:

[0064] 1) Based on similar projects, the number of times the solid phase stabilization material and the contaminated soil are mixed is initially determined to be n;

[0065] 2) Divide the mixed material into m portions as samples to be tested;

[0066] 3) Determine the content of the detection indexes IndexA and IndexB respectively. ij and b ij , i=1,2,…n; j=1,2,…m;

[0067] 4) Select a ij The maximum value is normalized to obtain the detection index IndexA content as A ij ;

[0068] 5) Select b ij The maximum value is normalized to obtain the detection index IndexB content B ij .

[0069] Step (2) constructs the coefficient of variation of the bivariate after mixing:

[0070] 1) Calculate the average values ​​of the contents of the detection indexes IndexA and IndexB after the i-th mixing, which are μAi and μ Bi , i=1,2,…n, j=1,2,…m;

[0071]

[0072]

[0073] 2) Calculate the standard deviation of the content of the detection indexes IndexA and IndexB after the i-th mixing, which are δ Ai and δ Bi , i=1,2,…n, j=1,2,…m;

[0074]

[0075]

[0076] 3) Calculate the bivariate coefficient of variation CV of the content of the detection indexes IndexA and IndexB after the i-th mixing i , i=1,2,…n, j=1,2,…m;

[0077]

[0078] Step (2) constructs a measurement model of the degree of mixing of solid phase stabilization materials and contaminated soil based on the bivariate coefficient of variation:

[0079] 1) Construct a relationship model between the number of equal mixing times and the corresponding bivariate coefficient of variation;

[0080]

[0081] In the formula: x is the number of times of mixing; y is the coefficient of variation of the two variables; a, b and c are fitting parameters;

[0082] 2) The above model is converted into a mixing degree equation, and the mixing degree corresponding to the maximum mixing number N is converted to 1 through the normalization method to construct a standardized mixing degree measurement model:

[0083]

[0084] Wherein: x is the number of uniform mixing, x = 1, 2, ... N; U is the uniform mixing degree, U ≤ 1; N is the maximum number of uniform mixing; a, b and c are the fitting parameters of formula (6).

[0085] The energy consumption of different mixing times is measured by mechanical energy consumption, and the calculation formula is as follows;

[0086] E i =F·P·i (Formula 8)

[0087] Where: Ei is the energy consumption of the ith mixing (yuan / m 3 ); F is the diesel consumption per cubic meter of contaminated soil (L / m 3 ); P is the unit price of diesel (yuan / L).

[0088] Step (3) constructs a unit energy consumption mixing degree model based on the mixing degree and energy consumption.

[0089]

[0090] Where: EU i is the unit energy consumption of the ith mixing (m3 / yuan); U i is the mixing degree of formula (7); E i is the energy consumption of formula (8).

[0091] The maximum number of mixing times is the minimum number of mixing times + 1 when the absolute value of the difference in the coefficient of variation of the two variables between two consecutive mixing times is less than 5%;

[0092] The absolute value calculation formula of the difference between the coefficient of variation of two adjacent mixing times is as follows:

[0093] Δy=|y i+1 -y i | (Formula 10)

[0094] Wherein: △y is the absolute value of the difference in the coefficient of variation of the two variables between two consecutive equal mixing times; when △y<5%, the maximum equal mixing times N=i+1.

[0095] Example 1

[0096] The contaminated soil repaired in this example is arsenic (As) contaminated soil from a site left over from an inorganic chemical plant in Dalian. Visible impurities and plant roots were removed, and the soil was naturally air-dried indoors before being sieved through a 2 mm sieve for later use. Iron salt was used as a solid phase stabilization material, with an addition amount of 5%.

[0097] The method for measuring the degree of mixing of the solid phase stabilization material and the contaminated soil in this embodiment has specific implementation steps (see Figure 1 ):

[0098] Step 1: Use solid phase stabilization materials and specific elements in contaminated soil as detection indicators, as follows:

[0099] (1) The solid phase stabilization material is used as the blending material (A) and the contaminated soil is used as the blended material (B);

[0100] (2) XRF detection was used to compare the contents of Fe, Ca, S, and P in the blending material (A) and the blended material (B). A and C B, calculate the ratio C of the two A / C B (See Table 1), select the Fe element with the largest ratio as the detection index of the blended material (IndexA);

[0101] Table 1 Element content (mg / kg)

[0102] Fe Ca S P <![CDATA[Blended material C A > 40300 23 8 12 <![CDATA[Blended material C B > 32300 9513 132 453 <![CDATA[Ratio C A / C B > 1.248 0.002 0.061 0.026

[0103] (3) Select the heavy metal As to be stabilized as the detection index of the blended material (Index B).

[0104] Step 2: Construct a measurement model of the degree of mixing of solid phase stabilization materials and contaminated soil through the content of the detection indicators after different mixing times, specifically:

[0105] 1. Mix the solid phase stabilization material and the contaminated soil, and determine the content of the detection index in step 1 under different mixing times, as follows:

[0106] (1) Based on the survey results of similar remediation projects in China, the number of times the solid phase stabilization material and the contaminated soil are mixed is initially set to n=4 in this embodiment;

[0107] (2) In this embodiment, an Allu bucket is used to evenly mix the As contaminated soil and Fe oxides. Each time the mixed material is about 0.5m 3 (bucket capacity), divide the mixed material into 5 equal parts as the samples to be tested;

[0108] (3) The content of Fe and As in the test indicators is respectively a ij and b ij , i=1,2,…n;j=1,2,…m(see Table 2);

[0109] Table 2 Determination results of test indicators (mg / kg)

[0110]

[0111]

[0112] (4) Select a ij The maximum value is normalized to obtain the detection index Fe content as A ij (See Table 3);

[0113] (5) Select b ij The maximum value is normalized to obtain the detection index As content as B ij (See Table 3).

[0114] Table 3 Normalized test results of test indicators (mg / kg)

[0115]

[0116] 2. The coefficient of variation of the bivariate variables after mixing is constructed by the difference in the content of the detection indicators at different mixing times; the details are as follows:

[0117] (1) According to formula 1 and formula 2, the average values ​​of Fe and As contents after the i-th mixing are calculated, which are μ Ai and μ Bi (See Table 4);

[0118] Table 4 Average values ​​of test indicators at different mixing times (mg / kg)

[0119] Mixed for the first time Mixed 2nd time Mixed for the 3rd time Mixed 4th time <![CDATA[μ Ai ]]> 0.81 0.85 0.84 0.81 <![CDATA[μ Bi ]]> 0.39 0.38 0.39 0.31

[0120] (2) According to Formula 3 and Formula 4, the standard deviations of Fe and As contents after the i-th mixing are calculated as δ Ai and δ Bi (See Table 5);

[0121] Table 5 Standard deviation of test indicators for different mixing times (mg / kg)

[0122] Mixed for the first time Mixed 2nd time Mixed for the 3rd time Mixed 4th time <![CDATA[δ Ai ]]> 0.10 0.06 0.02 0.02 <![CDATA[δ Bi ]]> 0.32 0.12 0.17 0.09

[0123] (3) According to formula 5, calculate the bivariate coefficient of variation CV of Fe and As content of the detection index after the i-th mixing i (See Table 6);

[0124] Table 6 Bivariate coefficient of variation of different mixing times

[0125] Mixed for the first time Mixed 2nd time Mixed for the 3rd time Mixed 4th time <![CDATA[CV i ]]> 0.37 0.15 0.19 0.11

[0126] 3. Construct a measurement model of the degree of mixing of solid-phase stabilization materials and contaminated soil based on the coefficient of variation of two variables to measure the degree of mixing corresponding to different mixing times, specifically:

[0127] (1) Construct a functional relationship model between the number of mixing times and the corresponding two-variable coefficient of variation, and obtain

[0128]

[0129] (2) The above model is converted into a mixing degree equation, and the mixing degree corresponding to the maximum mixing number N = 3 is converted to 1 through the normalization method to construct a standardized mixing degree measurement model:

[0130]

[0131] The maximum number of mixing times is the minimum number of mixing times + 1 when the absolute value of the difference in the bivariate coefficient of variation of two adjacent mixing times is less than 5% (see Table 7), that is, the maximum number of mixing times N = 2 + 1 = 3.

[0132] Table 7 Absolute value of the difference in the coefficient of variation of the two variables between two consecutive mixing times

[0133]

[0134] Note: In this embodiment, the fifth mixing is not carried out, so there is no calculation result of |y5-y4|.

[0135] 4. The energy consumption of different mixing times is shown in Table 8, and the mechanical energy consumption is used as the measurement, which is calculated by formula (8);

[0136] In this embodiment, a 50 shovel truck is used as the driving vehicle of the mixing equipment. The fuel tank of the truck is 290L, and the fuel consumption is about 15L per hour. About 100 cubic meters of contaminated soil can be mixed per hour. The price of No. 0 diesel in Liaoning Province is about 8 yuan / L.

[0137] Table 8 Energy consumption corresponding to different mixing times

[0138] Mixed for the first time Mixed 2nd time Mixed for the 3rd time F <![CDATA[15L / 100m 3 ]]> <![CDATA[15L / 100m 3 ]]> <![CDATA[15L / 100m 3 ]]> P 8 yuan / L 8 yuan / L 8 yuan / L <![CDATA[E i ]]> <![CDATA[1.2 yuan / m 3 > <![CDATA[2.4 yuan / m 3 > <![CDATA[3.6 yuan / m 3 >

[0139] Step 3: Using the mixing degree and energy consumption obtained in step 2, the mixing degree per unit energy consumption corresponding to different mixing times is obtained by formula (9), as shown in Table 9;

[0140] Table 9 Unit energy consumption and repair effect corresponding to different mixing times

[0141]

[0142] Note: Stabilization efficiency is the ratio of the reduction in the effective state of heavy metal As to the initial effective state.

[0143] Step 4: Select the unit energy consumption mixing degree EU i The maximum value corresponds to a mixing number of 2 times, which is the optimized mixing number for contaminated soil mixing stabilization treatment.

[0144] At the same time, it can be seen from Table 9 that after the number of equal mixing optimized by the above method is implemented, the stabilization efficiency of As contaminated soil remediation can reach 33.5%, and the energy consumption is significantly lower than that of 3 equal mixing, which can be used as a construction guide for the engineering construction of equal mixing stabilization of heavy metal contaminated soil.

[0145] The above content is a further detailed description of the present invention in combination with a specific preferred implementation case, and the specific implementation of the present invention cannot be considered to be limited to this. Without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for optimizing the number of times a solid phase stabilization material and contaminated soil are mixed, characterized in that: (1) Using solid-phase stabilized materials and specific elements in contaminated soil as detection indicators; (2) Constructing a measurement model for the degree of mixing of solid-phase stabilization materials and contaminated soil by measuring the contents of the above-mentioned detection indicators after different mixing times; (3) constructing a unit energy consumption mixing degree model based on the mixing degree and energy consumption obtained in step (2), and then obtaining the unit energy consumption mixing degree of different mixing times; (4) The mixing times corresponding to the maximum mixing degree per unit energy consumption is the optimized mixing times for the mixing and stabilization treatment of contaminated soil; The step (2) comprises mixing the solid phase stabilization material and the contaminated soil, and determining the content of the detection index under different mixing times; obtaining the bivariate coefficient of variation after mixing by the difference in the content of the detection index after different mixing times; the difference degree calculation index is the mean value and the standard deviation; constructing a solid phase stabilization material and contaminated soil mixing degree measurement model based on the bivariate coefficient of variation, which is used to measure the mixing degree corresponding to different mixing times, Step (3) constructs a unit energy consumption mixing degree model based on the mixing degree and energy consumption. Where: EU i is the unit energy consumption of the ith mixing, in m 3 / yuan;U i E is the degree of mixing; i For energy consumption.

2. The method for optimizing the number of times the solid phase stabilization material and the contaminated soil are mixed according to claim 1, characterized in that: The step (1) is: 1) The solid phase stabilization material is used as the blending material A and the contaminated soil is used as the blended material B; 2) Compare the content of Fe, Ca, S and P in the blended material A A and the content C in the blended material B B , select C A / C B The element with the largest ratio is used as the detection index IndexA of the blended material A; 3) Select the heavy metal to be stabilized as the detection index IndexB of the blended material B.

3. The method for optimizing the number of times the solid phase stabilization material and the contaminated soil are mixed according to claim 1, characterized in that: Step (2) Determine the content of the detection index under different mixing times: 1) The solid phase stabilization material and the contaminated soil are mixed for n times; 2) Divide the mixed material into m portions as samples to be tested; 3) Determine the content of the detection indexes IndexA and IndexB respectively. ij and b ij , i=1,2,…n; j=1,2,…m; 4) Select a ij The maximum value is normalized to obtain the detection index IndexA content as A ij ; 5) Select b ij The maximum value is normalized to obtain the detection index IndexB content B ij .

4. The method for optimizing the number of times the solid phase stabilization material and the contaminated soil are mixed according to claim 3, characterized in that: Step (2) constructs the coefficient of variation of the bivariate after mixing: 1) The average values ​​of the contents of the detection indexes IndexA and IndexB after the i-th mixing are μ Ai and μ Bi , i=1,2,…n,j=1,2,…m, the calculation formula is as follows; 2) The standard deviations of the contents of the detection indexes IndexA and IndexB after the i-th mixing are δ Ai and δ Bi , i=1,2,…n,j=1,2,…m, the calculation formula is as follows; 3) The coefficient of variation (CV) of the two variables of the content of IndexA and IndexB detected after the i-th mixing i , i=1,2,…n,j=1,2,…m, the calculation formula is as follows; 5. The method for optimizing the number of times the solid phase stabilization material and the contaminated soil are mixed according to claim 1, characterized in that: Step (2) constructs a measurement model of the degree of mixing of solid phase stabilization materials and contaminated soil based on the bivariate coefficient of variation: 1) Construct a relationship model between the number of equal mixing times and the corresponding bivariate coefficient of variation; In the formula: x is the number of times of mixing; y is the coefficient of variation of the two variables; a, b and c are fitting parameters; 2) The above model is converted into a mixing degree equation. By normalization, the mixing degree corresponding to the maximum mixing number N is converted to 1, and a standardized mixing degree measurement model is constructed: Wherein: x is the number of uniform mixing, x = 1, 2, ... N; U is the uniform mixing degree; N is the maximum number of uniform mixing; a, b and c are the fitting parameters of formula 6.

6. The method for optimizing the number of times the solid phase stabilization material and the contaminated soil are mixed according to claim 1, characterized in that: The energy consumption calculation formula for different mixing times is as follows; E i =F·P·i Formula 8 Where: E i is the energy consumption of the ith mixing, in yuan / m 3 ; F is the diesel consumption per cubic meter of contaminated soil, in L / m 3 ; P is the unit price of diesel, in Yuan / L.

7. The method for optimizing the number of times the solid phase stabilization material and the contaminated soil are mixed according to claim 1, characterized in that: The maximum mixing times are calculated as follows: Δy = |y i+1 - y i | Equation 10 Wherein: △y is the absolute value of the difference in the coefficient of variation of the two variables between two consecutive equal mixing times; when △y<5%, the maximum equal mixing times N=i+1.

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