Accurate site selection method for silt dam project

Abstract

The invention discloses a precise site selection method for a silt dam project. The method comprises the following steps: selecting a plurality of silt dam primary selection construction addresses according to basin planning; collecting dam site selected evaluation index data, and determining a weight coefficient of each evaluation index by utilizing expert scoring; processing dam site selected evaluation index data to obtain a first decision matrix of evaluation indexes, and calculating to obtain a second decision matrix; determining a positive ideal vector and a negative ideal vector of a second decision matrix of the evaluation index; respectively calculating Euclidean distances between the evaluation index and the positive ideal vector and the negative ideal vector of the second decision matrix; and respectively calculating the evaluation coefficient of the primary selection construction address of each silt dam, and selecting a selected address. According to the accurate site selection method for the silt dam project, the accuracy and reliability of site selection of the silt dam project are improved, the method has good applicability to site selection of the silt dam project, and the defects that indexes are not easy to quantify and the accuracy is not high in the site selection process of an existing silt dam project are overcome.

Description

Technical Field

[0001] The invention belongs to the technical field of construction engineering site selection and relates to a precise site selection method for a silt dam project. Background Art

[0002] Warping dams can intercept silt and rocks in mountain torrents or debris flows, slow down the slope of the ditch bed upstream of the dam, and reduce the flow rate and scouring force downstream. They are important green ecological, water conservancy, and soil and water conservation engineering measures. They are widely used in areas such as the Loess Plateau. Warping dams not only have the function of flood control and sediment retention, but also have the advantages of using local materials and being green and environmentally friendly. They are of great significance to the ecological protection and high-quality development of the Yellow River Basin.

[0003] The site selection of the silt dam project is affected by many restrictive factors such as the conditions of the filling soil, the geology of the dam base, and the construction conditions. Different from the general earth-rock dam, the benefits of the silt dam project focus on ecological value. Its site selection and construction mainly consider the satisfaction of local materials, safety and reliability, ease of operation and management, and the loss of project benefits. The existing site selection method for silt dam projects refers to the site selection method for earth-rock dams in water conservancy and hydropower projects. However, due to the different characteristics of the silt dam project itself, the existing site selection method for silt dam projects cannot completely and accurately select the optimal dam site. It relies too much on the subjective experience of designers for evaluation and determination, and lacks accurate quantification and scientific and applicable methods for the precise selection of silt dam projects, resulting in large differences in judgments among different designers and low reliability of the determined dam site.

[0004] In summary, the existing technology has the problems of low reliability in site selection for silt dam projects and over-reliance on subjective experience and judgment of designers. Summary of the invention

[0005] The purpose of the present invention is to provide a precise site selection method for a silt dam project, which solves the problems in the prior art of low reliability of site selection for silt dam projects and excessive reliance on subjective experience and judgment of designers.

[0006] The technical solution adopted by the present invention is a method for accurately selecting a site for a silt dam project, comprising the following steps: Step 1: Select several preliminary construction sites for silt dams based on the river basin planning; Step 2: Collect the evaluation index data of the dam site selection of the preliminary selected construction sites of the silt dam respectively, and use the expert scoring to determine the weight coefficient of each evaluation index in the dam site selection evaluation index data; Step 3: Processing the evaluation index data of the dam site selection by the range normal method to obtain the first decision matrix of the evaluation index, and calculating the second decision matrix by the first decision matrix and the weight coefficient; Step 4: Determine the positive ideal vector and the negative ideal vector of the second decision matrix of the evaluation index; Step 5: Calculate the Euclidean distance between the evaluation index and the positive ideal vector and the negative ideal vector of the second decision matrix respectively; Step 6: Calculate the evaluation coefficient of each preliminary selected construction site of the silt dam respectively, and select the preliminary selected construction site of the silt dam with the largest evaluation coefficient as the selected site.

[0007] The present invention is also characterized in that: The number of preliminary selected construction sites for the silt dam shall not be less than 3; The evaluation index data for dam site selection include the following evaluation indexes: maximum dam height u1 of the silt dam, maximum thickness of the loess layer at the dam foundation u2, thickness of collapsible loess at the foundation surface u3, elevation difference between the top surface of the useful layer of the material field and the dam top u4, sunshine duration at the transfer field u5, distance between the material field and the transfer field u6, distance between the silt dam and the transfer field u7, difference between the natural moisture content of the material field and the optimal moisture content u8, degree of dispersion of soil materials at the material field u9, and sediment retention capacity u10. 10 , flooded cultivated land area 11 、Number of immigrants relocated 12 .

[0008] The maximum dam height u1 of the silt dam is the maximum dam height of the silt dam to be constructed at the preliminary selected construction site of the silt dam; the maximum dam height u1 of the silt dam is a negative indicator and a low-optimal indicator; The maximum thickness u2 of the loess layer at the dam foundation is the maximum thickness of the loess layer at the dam foundation on the dam axis section of the silt dam to be constructed at the preliminary selected construction site of the silt dam; the maximum thickness u2 of the loess layer at the dam foundation is a negative indicator and a low-quality indicator; The collapsible loess thickness u3 of the foundation surface is the maximum thickness of medium and above collapsible loess or self-weight collapsible loess on the foundation surface of the silt dam on the dam axis section of the silt dam to be built at the preliminary construction site of the silt dam; the collapsible loess thickness u3 of the foundation surface is a negative indicator and a low-quality indicator; The elevation difference u4 between the top surface of the useful layer of the material yard and the dam crest is the elevation difference between the crest of the silt dam to be built at the preliminary construction site of the silt dam and the top surface of the useful layer of the main earth material yard of the silt dam; the elevation difference u4 between the top surface of the useful layer of the material yard and the dam crest is a negative indicator and a low-quality indicator.

[0009] The sunshine duration u5 of the transfer yard is the sunshine duration on the spring equinox day of the soil material construction transfer yard of the silt dam to be built at the preliminary construction site of the silt dam; the sunshine duration u5 of the transfer yard is a positive indicator and a high-quality indicator; The distance u6 between the material yard and the transfer yard is the straight-line distance from the plane centroid of the earth material yard of the silt dam to be constructed at the preliminary construction site of the silt dam to the plane centroid of the construction transfer yard; the distance u6 between the material yard and the transfer yard is a negative indicator and a low-optimal indicator; The distance u7 between the silt dam and the transfer yard is the straight-line distance from the midpoint of the dam axis of the silt dam to be constructed at the preliminary construction site of the silt dam to the plane centroid of the construction transfer yard; the distance u7 between the silt dam and the transfer yard is a negative indicator and a low-optimal indicator; The difference u8 between the natural moisture content of the material yard and the optimal moisture content is the difference between the natural moisture content of the soil material yard for the silt dam to be built at the preliminary construction site of the silt dam and the optimal moisture content of the soil itself; the difference u8 between the natural moisture content of the material yard and the optimal moisture content is a negative indicator and a low-quality indicator.

[0010] The dispersion degree of soil material in the material field u9 is the product of the dispersion degree D of the soil material field of the silt dam to be constructed at the preliminary construction site of the silt dam and the processing difficulty coefficient K; the dispersion degree of soil material in the material field u9 is a negative indicator and a low-quality indicator; The calculation formula for the dispersion D of the earth material field to be built for the silt dam is as follows:

[0011] in, Indicates the dispersion of the soil material field of the silt dam to be built at the preliminary construction site of the silt dam, It indicates the content of colloid or clay in the soil material of the soil material field of the silt dam to be built at the preliminary construction site of the silt dam measured by the unconventional densitometer test. It indicates the content of colloid particles or clay particles in the soil material of the soil material field of the silt dam to be constructed at the preliminary construction site of the silt dam measured by conventional densitometer test; The values ​​of the processing difficulty coefficient K of the soil material field for the construction of the silt dam are as follows: if the soil material of the soil material field for the construction of the silt dam is non-dispersed soil, the value of the processing difficulty coefficient K is 1; if the soil material of the soil material field for the construction of the silt dam is transitional soil, the value of the processing difficulty coefficient K is 1.5; if the soil material of the soil material field for the construction of the silt dam is physically dispersed soil, the value of the processing difficulty coefficient K is 2; if the soil material of the soil material field for the construction of the silt dam is chemically dispersed soil, the value of the processing difficulty coefficient K is 2.5; if the soil material of the soil material field for the construction of the silt dam is physically-chemically dispersed soil, the value of the processing difficulty coefficient K is 3; Sediment retention capacity 10 The accumulated sedimentation volume of the silt dam to be constructed at the preliminary selected construction site after reaching the designed sedimentation period; the sediment retention capacity u 10 It is a positive indicator and a high-quality indicator; The design sedimentation period is determined according to the basin planning. If the design sedimentation period is not determined in the basin planning, the design sedimentation period is 30 years for small and medium-sized silt dams to be built, and 50 years for large silt dams to be built. Flooded cultivated land area 11 It is the sum of all cultivated land areas in the area below the normal water level of the dam to be built and the temporary flooded area above the normal water level of the reservoir at the preliminary construction site of the dam; the flooded cultivated land area u 11 It is a negative indicator and a low-quality indicator; Number of immigrants relocated12 The number of immigrants who need to be relocated and resettled within the scope of land acquisition for the construction of the silt dam at the preliminary selected construction site; the number of immigrants to be relocated u 12 It is a negative indicator and a low-quality indicator.

[0012] The experts who participate in the expert scoring are persons with the professional title of senior engineer or above in the design of water conservancy projects or water conservation projects. The number of experts who participate in the expert scoring meets the following requirements: no less than 3 people when the silt dam to be built is a small water conservancy project, no less than 5 people when the silt dam to be built is a medium-sized water conservancy project, and no less than 7 people when the silt dam to be built is a large water conservancy project; the number of experts who belong to the area where the project is located among the experts who participate in the expert scoring shall not be less than 30% of the total number of experts who participate in the scoring; The sum of the weight coefficients of each evaluation index is 100%; the weight coefficient of each evaluation index shall not be less than 3% and not more than 20%. If the weight coefficient of each evaluation index is less than 3% or greater than 20%, an additional expert shall be added to re-determine the weight coefficient of each evaluation index in the dam site selection evaluation index data.

[0013] The first decision matrix of the evaluation index is obtained in the following way: X=(x ij )m×12 , in, X Represents the first decision matrix of the evaluation index, x ij Indicates i The first site of the preliminary selection of the construction site of the silt dam j The first decision value of the evaluation index, It indicates the number of preliminary selected construction sites for check dams; If the evaluation index is a high-quality index, the calculation formula for the first decision value of the evaluation index is as follows:

[0014] in, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The first decision value of the evaluation index, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The basic value of the evaluation index, The first one indicates the preliminary construction site of the silt dam. j The minimum value among the basic values ​​of the evaluation indicators, The first one indicates the preliminary construction site of the silt dam. j The maximum value among the basic values ​​of the evaluation indicators, It indicates the number of preliminary selected construction sites for check dams; If the evaluation index is a high-quality index, the calculation formula for the first decision value of the evaluation index is as follows:

[0015] in, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The first decision value of the evaluation index, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The basic value of the evaluation index, The first one indicates the preliminary construction site of the silt dam. j The minimum value among the basic values ​​of the evaluation indicators, The first one indicates the preliminary construction site of the silt dam. j The maximum value among the basic values ​​of the evaluation indicators, Indicates the number of preliminary selected construction sites for check dams.

[0016] The calculation formula for the positive ideal vector is as follows: , in, represents the positive ideal vector of the evaluation index, The maximum value of the second decision value of the first evaluation index for the preliminary selection of the construction site of the silt dam, The maximum value of the second decision value of the second evaluation index for the preliminary selection of the construction site of the silt dam, The maximum value among the second decision values ​​of the twelfth evaluation index of the preliminary selection of the construction site of the silt dam; The calculation formula for the negative ideal vector is as follows: , in, represents the negative ideal vector of the evaluation index, The minimum value of the second decision value of the first evaluation index for the preliminary selection of the construction site of the silt dam, represents the minimum value of the second decision value of the second evaluation index for the preliminary selection of the construction site of the silt dam, It represents the minimum value among the second decision values ​​of the twelfth evaluation indicator for the preliminary selection of the construction site of the silt dam.

[0017] The calculation formula of the Euclidean distance between the evaluation index and the positive ideal vector of the second decision matrix is ​​as follows:

[0018] in, Indicates iThe Euclidean distance between each evaluation index of the preliminary construction site of the silt dam and the positive ideal vector of the second decision matrix, The first one indicates the preliminary construction site of the silt dam. j The maximum value of the second decision values ​​of the evaluation indicators, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The second decision value of the evaluation index, i Indicates i The preliminary construction site of the silt dam is j Indicates the first selected construction site of the silt dam j evaluation indicators, It indicates the total number of evaluation indicators in the preliminary selection of construction sites for check dams; The calculation formula of the Euclidean distance between the evaluation index and the negative ideal vector of the second decision matrix is ​​as follows:

[0019] in, Indicates i The Euclidean distance between each evaluation index of the preliminary construction site of the silt dam and the negative ideal vector of the second decision matrix, The first one indicates the preliminary construction site of the silt dam. j The minimum value of the second decision value of the evaluation index, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The second decision value of the evaluation index, i Indicates i The preliminary construction site of the silt dam is j Indicates the first selected construction site of the silt dam j evaluation indicators, It indicates the total number of evaluation indicators in the preliminary selection of construction sites for check dams; No. i The first site of the preliminary selection of the construction site of the silt dam j The second decision value of the evaluation index is obtained by The weight coefficient of the evaluation index is The first soil material site to be evaluated It is obtained by multiplying the first decision values ​​of the evaluation indicators.

[0020] The calculation formula for the evaluation coefficient of the preliminary construction site of the silt dam is as follows: , in, Indicates i The evaluation coefficient of the preliminary selection of the construction site of the silt dam, Indicates iThe Euclidean distance between the initial construction site of the silt dam and the negative ideal vector of the second decision matrix, Indicates i The Euclidean distance between the initial construction site of the silt dam and the positive ideal vector of the second decision matrix.

[0021] The beneficial effects of the present invention are as follows: the present invention improves the accuracy and reliability of site selection for silt dam projects, has good applicability for site selection for silt dam projects, solves the shortcomings of difficult quantification and low accuracy of indicators in the existing site selection process for silt dam projects, reduces the adverse effects of human subjective decision-making errors, does not require engineering quantity and investment calculations, reduces the construction decision-making risks brought about by the uncertainty of the silt dam site, better plays the ecological benefits of the silt dam, and promotes ecological protection and high-quality development in the Yellow River Basin of the Loess Plateau. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic flow chart of the precise site selection method for a silt dam project of the present invention. DETAILED DESCRIPTION

[0023] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Precise site selection method for silt dam project, such as Figure 1 As shown, the following steps are included: Step 1: Select several preliminary construction sites for silt dams based on the river basin planning; The number of preliminary selected construction sites for the silt dam shall not be less than 3; Step 2: Collect the evaluation index data of the dam site selection of the preliminary selected construction sites of the silt dam respectively, and use the expert scoring to determine the weight coefficient of each evaluation index in the dam site selection evaluation index data; The evaluation index data for dam site selection include the following evaluation indexes: maximum dam height u1 of the silt dam, maximum thickness of the loess layer at the dam foundation u2, thickness of collapsible loess at the foundation surface u3, elevation difference between the top surface of the useful layer of the material field and the dam top u4, sunshine duration at the transfer field u5, distance between the material field and the transfer field u6, distance between the silt dam and the transfer field u7, difference between the natural moisture content of the material field and the optimal moisture content u8, degree of dispersion of soil materials at the material field u9, and sediment retention capacity u10. 10 , flooded cultivated land area 11 、Number of immigrants relocated 12 ; The maximum dam height u1 of the silt dam is the maximum dam height of the silt dam to be constructed at the preliminary selected construction site of the silt dam; the maximum dam height u1 of the silt dam is a negative indicator and a low-optimal indicator; The maximum thickness u2 of the loess layer at the dam foundation is the maximum thickness of the loess layer at the dam foundation on the dam axis section of the silt dam to be constructed at the preliminary selected construction site of the silt dam; the maximum thickness u2 of the loess layer at the dam foundation is a negative indicator and a low-quality indicator; The collapsible loess thickness u3 of the foundation surface is the maximum thickness of medium and above collapsible loess or self-weight collapsible loess on the foundation surface of the silt dam on the dam axis section of the silt dam to be built at the preliminary construction site of the silt dam; the collapsible loess thickness u3 of the foundation surface is a negative indicator and a low-quality indicator; The elevation difference u4 between the top surface of the useful layer of the material field and the dam crest is the elevation difference between the dam crest of the silt dam to be constructed at the preliminary construction site of the silt dam and the top surface of the useful layer of the main soil material field of the silt dam; the elevation difference u4 between the top surface of the useful layer of the material field and the dam crest is a negative indicator and a low-quality indicator; The sunshine duration u5 of the transfer yard is the sunshine duration on the spring equinox day of the soil material construction transfer yard of the silt dam to be built at the preliminary construction site of the silt dam; the sunshine duration u5 of the transfer yard is a positive indicator and a high-quality indicator; The distance u6 between the material yard and the transfer yard is the straight-line distance from the plane centroid of the earth material yard of the silt dam to be constructed at the preliminary construction site of the silt dam to the plane centroid of the construction transfer yard; the distance u6 between the material yard and the transfer yard is a negative indicator and a low-optimal indicator; The distance u7 between the silt dam and the transfer yard is the straight-line distance from the midpoint of the dam axis of the silt dam to be constructed at the preliminary construction site of the silt dam to the plane centroid of the construction transfer yard; the distance u7 between the silt dam and the transfer yard is a negative indicator and a low-optimal indicator; The difference u8 between the natural moisture content of the material field and the optimal moisture content is the difference between the natural moisture content of the soil material field of the silt dam to be built at the preliminary construction site of the silt dam and the optimal moisture content of the soil itself; the difference u8 between the natural moisture content of the material field and the optimal moisture content is a negative indicator and a low-quality indicator; The dispersion degree of soil material in the material field u9 is the product of the dispersion degree D of the soil material field of the silt dam to be constructed at the preliminary construction site of the silt dam and the processing difficulty coefficient K; the dispersion degree of soil material in the material field u9 is a negative indicator and a low-quality indicator; The calculation formula for the dispersion D of the earth material field to be built for the silt dam is as follows:

[0025] in, Indicates the dispersion of the soil material field of the silt dam to be built at the preliminary construction site of the silt dam, It indicates the content of colloid or clay in the soil material of the soil material field of the silt dam to be built at the preliminary construction site of the silt dam measured by the unconventional densitometer test. It indicates the content of colloid particles or clay particles in the soil material of the soil material field of the silt dam to be constructed at the preliminary construction site of the silt dam measured by conventional densitometer test; The values ​​of the processing difficulty coefficient K of the soil material field for the construction of the silt dam are as follows: if the soil material of the soil material field for the construction of the silt dam is non-dispersed soil, the value of the processing difficulty coefficient K is 1; if the soil material of the soil material field for the construction of the silt dam is transitional soil, the value of the processing difficulty coefficient K is 1.5; if the soil material of the soil material field for the construction of the silt dam is physically dispersed soil, the value of the processing difficulty coefficient K is 2; if the soil material of the soil material field for the construction of the silt dam is chemically dispersed soil, the value of the processing difficulty coefficient K is 2.5; if the soil material of the soil material field for the construction of the silt dam is physically-chemically dispersed soil, the value of the processing difficulty coefficient K is 3; Sediment retention capacity 10 The accumulated sedimentation volume of the silt dam to be constructed at the preliminary selected construction site after reaching the designed sedimentation period; the sediment retention capacity u 10 It is a positive indicator and a high-quality indicator; The design sedimentation period is determined according to the basin planning. If the design sedimentation period is not determined in the basin planning, the design sedimentation period is 30 years for small and medium-sized silt dams to be built, and 50 years for large silt dams to be built. Flooded cultivated land area 11 It is the sum of all cultivated land areas in the area below the normal water level of the dam to be built and the temporary flooded area above the normal water level of the reservoir at the preliminary construction site of the dam; the flooded cultivated land area u 11 It is a negative indicator and a low-quality indicator; Number of immigrants relocated 12 The number of immigrants who need to be relocated and resettled within the scope of land acquisition for the construction of the silt dam at the preliminary selected construction site; the number of immigrants to be relocated u 12 It is a negative indicator and a low-quality indicator; The experts who participate in the expert scoring are persons with the professional title of senior engineer or above in the design of water conservancy projects or water conservation projects. The number of experts who participate in the expert scoring meets the following requirements: no less than 3 people when the silt dam to be built is a small water conservancy project, no less than 5 people when the silt dam to be built is a medium-sized water conservancy project, and no less than 7 people when the silt dam to be built is a large water conservancy project; the number of experts who belong to the area where the project is located among the experts who participate in the expert scoring shall not be less than 30% of the total number of experts who participate in the scoring; The sum of the weight coefficients of each evaluation index is 100%; the weight coefficient of each evaluation index shall not be less than 3% and not more than 20%. If the weight coefficient of each evaluation index is less than 3% or greater than 20%, an additional expert shall be added to re-determine the weight coefficient of each evaluation index in the evaluation index data for dam site selection; Step 3: Processing the evaluation index data of the dam site selection by the range normal method to obtain the first decision matrix of the evaluation index, and calculating the second decision matrix by the first decision matrix and the weight coefficient; The first decision matrix of the evaluation index is obtained in the following way: X=(x ij )m×12 , in, X Represents the first decision matrix of the evaluation index, x ij Indicates i The first site of the preliminary selection of the construction site of the silt dam j The first decision value of the evaluation index, It indicates the number of preliminary selected construction sites for check dams; If the evaluation index is a high-quality index, the calculation formula for the first decision value of the evaluation index is as follows:

[0026] in, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The first decision value of the evaluation index, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The basic value of the evaluation index, The first one indicates the preliminary construction site of the silt dam. j The minimum value among the basic values ​​of the evaluation indicators, The first one indicates the preliminary construction site of the silt dam. j The maximum value among the basic values ​​of the evaluation indicators, It indicates the number of preliminary selected construction sites for check dams; If the evaluation index is a high-quality index, the calculation formula for the first decision value of the evaluation index is as follows:

[0027] in, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The first decision value of the evaluation index, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The basic value of the evaluation index, The first one indicates the preliminary construction site of the silt dam. j The minimum value among the basic values ​​of the evaluation indicators, The first one indicates the preliminary construction site of the silt dam. j The maximum value among the basic values ​​of the evaluation indicators, It indicates the number of preliminary selected construction sites for check dams; Step 4: Determine the positive ideal vector and the negative ideal vector of the second decision matrix of the evaluation index; The calculation formula for the positive ideal vector is as follows: , in, represents the positive ideal vector of the evaluation index, The maximum value of the second decision value of the first evaluation index for the preliminary selection of the construction site of the silt dam, The maximum value of the second decision value of the second evaluation index for the preliminary selection of the construction site of the silt dam, The maximum value among the second decision values ​​of the twelfth evaluation index of the preliminary selection of the construction site of the silt dam; The calculation formula for the negative ideal vector is as follows: , in, represents the negative ideal vector of the evaluation index, The minimum value of the second decision value of the first evaluation index for the preliminary selection of the construction site of the silt dam, represents the minimum value of the second decision value of the second evaluation index for the preliminary selection of the construction site of the silt dam, The minimum value among the second decision values ​​of the twelfth evaluation index of the preliminary selection of the construction site of the silt dam; Step 5: Calculate the Euclidean distance between the evaluation index and the positive ideal vector and the negative ideal vector of the second decision matrix respectively; The calculation formula of the Euclidean distance between the evaluation index and the positive ideal vector of the second decision matrix is ​​as follows:

[0028] in, Indicates i The Euclidean distance between each evaluation index of the preliminary construction site of the silt dam and the positive ideal vector of the second decision matrix, The first one indicates the preliminary construction site of the silt dam. j The maximum value of the second decision values ​​of the evaluation indicators, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The second decision value of the evaluation index, i Indicates i The preliminary construction site of the silt dam is j Indicates the first selected construction site of the silt dam j evaluation indicators, It indicates the total number of evaluation indicators in the preliminary selection of construction sites for check dams; The calculation formula of the Euclidean distance between the evaluation index and the negative ideal vector of the second decision matrix is ​​as follows:

[0029] in, Indicates i The Euclidean distance between each evaluation index of the preliminary construction site of the silt dam and the negative ideal vector of the second decision matrix, The first one indicates the preliminary construction site of the silt dam. j The minimum value of the second decision value of the evaluation index, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The second decision value of the evaluation index, i Indicates i The preliminary construction site of the silt dam is j Indicates the first selected construction site of the silt dam j evaluation indicators, It indicates the total number of evaluation indicators in the preliminary selection of construction sites for check dams; No. i The first site of the preliminary selection of the construction site of the silt dam j The second decision value of the evaluation index is obtained by The weight coefficient of the evaluation index is The first soil material site to be evaluated The first decision value of each evaluation index is multiplied to obtain; Step 6: Calculate the evaluation coefficient of each preliminary selected construction site of the silt dam respectively, and select the preliminary selected construction site of the silt dam with the largest evaluation coefficient as the selected site; The calculation formula for the evaluation coefficient of the preliminary construction site of the silt dam is as follows: , in, Indicates i The evaluation coefficient of the preliminary selection of the construction site of the silt dam, Indicates i The Euclidean distance between the initial construction site of the silt dam and the negative ideal vector of the second decision matrix, Indicates i The Euclidean distance between the initial construction site of the silt dam and the positive ideal vector of the second decision matrix.

[0030] Example 1 This embodiment proposes a precise site selection method for a silt dam project, such as Figure 1 As shown, the following steps are included: Step 1: Select several preliminary construction sites for silt dams based on the river basin planning; Step 2: Collect the evaluation index data of the dam site selection of the preliminary selected construction sites of the silt dam respectively, and use the expert scoring to determine the weight coefficient of each evaluation index in the dam site selection evaluation index data; Step 3: Processing the evaluation index data of the dam site selection by the range normal method to obtain the first decision matrix of the evaluation index, and calculating the second decision matrix by the first decision matrix and the weight coefficient; Step 4: Determine the positive ideal vector and the negative ideal vector of the second decision matrix of the evaluation index; Step 5: Calculate the Euclidean distance between the evaluation index and the positive ideal vector and the negative ideal vector of the second decision matrix respectively; Step 6: Calculate the evaluation coefficient of each preliminary selected construction site of the silt dam respectively, and select the preliminary selected construction site of the silt dam with the largest evaluation coefficient as the selected site.

[0031] Example 2 This embodiment proposes a precise site selection method for a silt dam project, such as Figure 1 As shown, the following steps are included: Step 1: Select several preliminary construction sites for silt dams based on the river basin planning; The number of preliminary selected construction sites for the silt dam shall not be less than 3; Step 2: Collect the evaluation index data of the dam site selection of the preliminary selected construction sites of the silt dam respectively, and use the expert scoring to determine the weight coefficient of each evaluation index in the dam site selection evaluation index data; The evaluation index data for dam site selection include the following evaluation indexes: maximum dam height u1 of the silt dam, maximum thickness of the loess layer at the dam foundation u2, thickness of collapsible loess at the foundation surface u3, elevation difference between the top surface of the useful layer of the material field and the dam top u4, sunshine duration at the transfer field u5, distance between the material field and the transfer field u6, distance between the silt dam and the transfer field u7, difference between the natural moisture content of the material field and the optimal moisture content u8, degree of dispersion of soil materials at the material field u9, and sediment retention capacity u10. 10 , flooded cultivated land area 11 、Number of immigrants relocated 12 ; Step 3: Processing the evaluation index data of the dam site selection by the range normal method to obtain the first decision matrix of the evaluation index, and calculating the second decision matrix by the first decision matrix and the weight coefficient; Step 4: Determine the positive ideal vector and the negative ideal vector of the second decision matrix of the evaluation index; Step 5: Calculate the Euclidean distance between the evaluation index and the positive ideal vector and the negative ideal vector of the second decision matrix respectively; Step 6: Calculate the evaluation coefficient of each preliminary selected construction site of the silt dam respectively, and select the preliminary selected construction site of the silt dam with the largest evaluation coefficient as the selected site.

[0032] Example 3 This embodiment proposes a precise site selection method for a silt dam project, such as Figure 1 As shown, the following steps are included: Step 1: Select several preliminary construction sites for silt dams based on the river basin planning; The number of preliminary selected construction sites for the silt dam shall not be less than 3; Step 2: Collect the evaluation index data of the dam site selection of the preliminary selected construction sites of the silt dam respectively, and use the expert scoring to determine the weight coefficient of each evaluation index in the dam site selection evaluation index data; The evaluation index data for dam site selection include the following evaluation indexes: maximum dam height u1 of the silt dam, maximum thickness of the loess layer at the dam foundation u2, thickness of collapsible loess at the foundation surface u3, elevation difference between the top surface of the useful layer of the material field and the dam top u4, sunshine duration at the transfer field u5, distance between the material field and the transfer field u6, distance between the silt dam and the transfer field u7, difference between the natural moisture content of the material field and the optimal moisture content u8, degree of dispersion of soil materials at the material field u9, and sediment retention capacity u10. 10 , flooded cultivated land area 11 、Number of immigrants relocated 12 ; The maximum dam height u1 of the silt dam is the maximum dam height of the silt dam to be constructed at the preliminary selected construction site of the silt dam; the maximum dam height u1 of the silt dam is a negative indicator and a low-optimal indicator; The maximum thickness u2 of the loess layer at the dam foundation is the maximum thickness of the loess layer at the dam foundation on the dam axis section of the silt dam to be constructed at the preliminary selected construction site of the silt dam; the maximum thickness u2 of the loess layer at the dam foundation is a negative indicator and a low-quality indicator; The collapsible loess thickness u3 of the foundation surface is the maximum thickness of medium and above collapsible loess or self-weight collapsible loess on the foundation surface of the silt dam on the dam axis section of the silt dam to be built at the preliminary construction site of the silt dam; the collapsible loess thickness u3 of the foundation surface is a negative indicator and a low-quality indicator; The elevation difference u4 between the top surface of the useful layer of the material yard and the dam crest is the elevation difference between the crest of the silt dam to be built at the preliminary construction site of the silt dam and the top surface of the useful layer of the main earth material yard of the silt dam; the elevation difference u4 between the top surface of the useful layer of the material yard and the dam crest is a negative indicator and a low-quality indicator.

[0033] The sunshine duration u5 of the transfer yard is the sunshine duration on the spring equinox day of the soil material construction transfer yard of the silt dam to be built at the preliminary construction site of the silt dam; the sunshine duration u5 of the transfer yard is a positive indicator and a high-quality indicator; The distance u6 between the material yard and the transfer yard is the straight-line distance from the plane centroid of the earth material yard of the silt dam to be constructed at the preliminary construction site of the silt dam to the plane centroid of the construction transfer yard; the distance u6 between the material yard and the transfer yard is a negative indicator and a low-optimal indicator; The distance u7 between the silt dam and the transfer yard is the straight-line distance from the midpoint of the dam axis of the silt dam to be constructed at the preliminary construction site of the silt dam to the plane centroid of the construction transfer yard; the distance u7 between the silt dam and the transfer yard is a negative indicator and a low-optimal indicator; The difference u8 between the natural moisture content of the material yard and the optimal moisture content is the difference between the natural moisture content of the soil material yard for the silt dam to be built at the preliminary construction site of the silt dam and the optimal moisture content of the soil itself; the difference u8 between the natural moisture content of the material yard and the optimal moisture content is a negative indicator and a low-quality indicator.

[0034] The dispersion degree of soil material in the material field u9 is the product of the dispersion degree D of the soil material field of the silt dam to be constructed at the preliminary construction site of the silt dam and the processing difficulty coefficient K; the dispersion degree of soil material in the material field u9 is a negative indicator and a low-quality indicator; The calculation formula for the dispersion D of the earth material field to be built for the silt dam is as follows:

[0035] in, Indicates the dispersion of the soil material field of the silt dam to be built at the preliminary construction site of the silt dam, It indicates the content of colloid or clay in the soil material of the soil material field of the silt dam to be built at the preliminary construction site of the silt dam measured by the unconventional densitometer test. It indicates the content of colloid particles or clay particles in the soil material of the soil material field of the silt dam to be constructed at the preliminary construction site of the silt dam measured by conventional densitometer test; The values ​​of the processing difficulty coefficient K of the soil material field for the construction of the silt dam are as follows: if the soil material of the soil material field for the construction of the silt dam is non-dispersed soil, the value of the processing difficulty coefficient K is 1; if the soil material of the soil material field for the construction of the silt dam is transitional soil, the value of the processing difficulty coefficient K is 1.5; if the soil material of the soil material field for the construction of the silt dam is physically dispersed soil, the value of the processing difficulty coefficient K is 2; if the soil material of the soil material field for the construction of the silt dam is chemically dispersed soil, the value of the processing difficulty coefficient K is 2.5; if the soil material of the soil material field for the construction of the silt dam is physically-chemically dispersed soil, the value of the processing difficulty coefficient K is 3; Sediment retention capacity 10 The accumulated sedimentation volume of the silt dam to be constructed at the preliminary selected construction site after reaching the designed sedimentation period; the sediment retention capacity u 10 It is a positive indicator and a high-quality indicator; The design sedimentation period is determined according to the basin planning. If the design sedimentation period is not determined in the basin planning, the design sedimentation period is 30 years for small and medium-sized silt dams to be built, and 50 years for large silt dams to be built. Flooded cultivated land area 11 It is the sum of all cultivated land areas in the area below the normal water level of the dam to be built and the temporary flooded area above the normal water level of the reservoir at the preliminary construction site of the dam; the flooded cultivated land area u 11 It is a negative indicator and a low-quality indicator; Number of immigrants relocated 12The number of immigrants who need to be relocated and resettled within the scope of land acquisition for the construction of the silt dam at the preliminary selected construction site; the number of immigrants to be relocated u 12 It is a negative indicator and a low-quality indicator.

[0036] Step 3: Processing the evaluation index data of the dam site selection by the range normal method to obtain the first decision matrix of the evaluation index, and calculating the second decision matrix by the first decision matrix and the weight coefficient; Step 4: Determine the positive ideal vector and the negative ideal vector of the second decision matrix of the evaluation index; Step 5: Calculate the Euclidean distance between the evaluation index and the positive ideal vector and the negative ideal vector of the second decision matrix respectively; Step 6: Calculate the evaluation coefficient of each preliminary selected construction site of the silt dam respectively, and select the preliminary selected construction site of the silt dam with the largest evaluation coefficient as the selected site.

[0037] Example 4 This embodiment proposes a precise site selection method for a silt dam project, such as Figure 1 As shown, the following steps are included: Step 1: Select several preliminary construction sites for silt dams based on the river basin planning; Step 2: Collect the evaluation index data of the dam site selection of the preliminary selected construction sites of the silt dam respectively, and use the expert scoring to determine the weight coefficient of each evaluation index in the dam site selection evaluation index data; The experts who participate in the expert scoring are persons with the professional title of senior engineer or above in the design of water conservancy projects or water conservation projects. The number of experts who participate in the expert scoring meets the following requirements: no less than 3 people when the silt dam to be built is a small water conservancy project, no less than 5 people when the silt dam to be built is a medium-sized water conservancy project, and no less than 7 people when the silt dam to be built is a large water conservancy project; the number of experts who belong to the area where the project is located among the experts who participate in the expert scoring shall not be less than 30% of the total number of experts who participate in the scoring; The sum of the weight coefficients of each evaluation index is 100%; the weight coefficient of each evaluation index shall not be less than 3% and not more than 20%. If the weight coefficient of each evaluation index is less than 3% or greater than 20%, an additional expert shall be added to re-determine the weight coefficient of each evaluation index in the dam site selection evaluation index data.

[0038] Step 3: Processing the evaluation index data of the dam site selection by the range normal method to obtain the first decision matrix of the evaluation index, and calculating the second decision matrix by the first decision matrix and the weight coefficient; Step 4: Determine the positive ideal vector and the negative ideal vector of the second decision matrix of the evaluation index; Step 5: Calculate the Euclidean distance between the evaluation index and the positive ideal vector and the negative ideal vector of the second decision matrix respectively; Step 6: Calculate the evaluation coefficient of each preliminary selected construction site of the silt dam respectively, and select the preliminary selected construction site of the silt dam with the largest evaluation coefficient as the selected site.

[0039] Example 5 This embodiment proposes a precise site selection method for a silt dam project, such as Figure 1 As shown, the following steps are included: Step 1: Select several preliminary construction sites for silt dams based on the river basin planning; Step 2: Collect the evaluation index data of the dam site selection of the preliminary selected construction sites of the silt dam respectively, and use the expert scoring to determine the weight coefficient of each evaluation index in the dam site selection evaluation index data; Step 3: Processing the evaluation index data of the dam site selection by the range normal method to obtain the first decision matrix of the evaluation index, and calculating the second decision matrix by the first decision matrix and the weight coefficient; The first decision matrix of the evaluation index is obtained in the following way: X=(x ij )m×12 , in, X Represents the first decision matrix of the evaluation index, x ij Indicates i The first site of the preliminary selection of the construction site of the silt dam j The first decision value of the evaluation index, It indicates the number of preliminary selected construction sites for check dams; If the evaluation index is a high-quality index, the calculation formula for the first decision value of the evaluation index is as follows:

[0040] in, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The first decision value of the evaluation index, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The basic value of the evaluation index, The first one indicates the preliminary construction site of the silt dam. j The minimum value among the basic values ​​of the evaluation indicators, The first one indicates the preliminary construction site of the silt dam. j The maximum value among the basic values ​​of the evaluation indicators, It indicates the number of preliminary selected construction sites for check dams; If the evaluation index is a high-quality index, the calculation formula for the first decision value of the evaluation index is as follows:

[0041] in, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The first decision value of the evaluation index, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The basic value of the evaluation index, The first one indicates the preliminary construction site of the silt dam. j The minimum value among the basic values ​​of the evaluation indicators, The first one indicates the preliminary construction site of the silt dam. j The maximum value among the basic values ​​of the evaluation indicators, Indicates the number of preliminary selected construction sites for check dams.

[0042] Step 4: Determine the positive ideal vector and the negative ideal vector of the second decision matrix of the evaluation index; The calculation formula for the positive ideal vector is as follows: , in, represents the positive ideal vector of the evaluation index, The maximum value of the second decision value of the first evaluation index for the preliminary selection of the construction site of the silt dam, The maximum value of the second decision value of the second evaluation index for the preliminary selection of the construction site of the silt dam, The maximum value among the second decision values ​​of the twelfth evaluation index of the preliminary selection of the construction site of the silt dam; The calculation formula for the negative ideal vector is as follows: , in, represents the negative ideal vector of the evaluation index, The minimum value of the second decision value of the first evaluation index for the preliminary selection of the construction site of the silt dam, represents the minimum value of the second decision value of the second evaluation index for the preliminary selection of the construction site of the silt dam, It represents the minimum value among the second decision values ​​of the twelfth evaluation indicator for the preliminary selection of the construction site of the silt dam.

[0043] Step 5: Calculate the Euclidean distance between the evaluation index and the positive ideal vector and the negative ideal vector of the second decision matrix respectively; Step 6: Calculate the evaluation coefficient of each preliminary selected construction site of the silt dam respectively, and select the preliminary selected construction site of the silt dam with the largest evaluation coefficient as the selected site.

[0044] Example 6 This embodiment proposes a precise site selection method for a silt dam project, such as Figure 1 As shown, the following steps are included: Step 1: Select several preliminary construction sites for silt dams based on the river basin planning; Step 2: Collect the evaluation index data of the dam site selection of the preliminary selected construction sites of the silt dam respectively, and use the expert scoring to determine the weight coefficient of each evaluation index in the dam site selection evaluation index data; Step 3: Processing the evaluation index data of the dam site selection by the range normal method to obtain the first decision matrix of the evaluation index, and calculating the second decision matrix by the first decision matrix and the weight coefficient; Step 4: Determine the positive ideal vector and the negative ideal vector of the second decision matrix of the evaluation index; Step 5: Calculate the Euclidean distance between the evaluation index and the positive ideal vector and the negative ideal vector of the second decision matrix respectively; The calculation formula of the Euclidean distance between the evaluation index and the positive ideal vector of the second decision matrix is ​​as follows:

[0045] in, Indicates i The Euclidean distance between each evaluation index of the preliminary construction site of the silt dam and the positive ideal vector of the second decision matrix, The first one indicates the preliminary construction site of the silt dam. j The maximum value of the second decision values ​​of the evaluation indicators, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The second decision value of the evaluation index, i Indicates i The preliminary construction site of the silt dam is j Indicates the first selected construction site of the silt dam j evaluation indicators, It indicates the total number of evaluation indicators in the preliminary selection of construction sites for check dams; The calculation formula of the Euclidean distance between the evaluation index and the negative ideal vector of the second decision matrix is ​​as follows:

[0046] in, Indicates i The Euclidean distance between each evaluation index of the preliminary construction site of the silt dam and the negative ideal vector of the second decision matrix, The first one indicates the preliminary construction site of the silt dam. j The minimum value of the second decision value of the evaluation index, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The second decision value of the evaluation index, iIndicates i The preliminary construction site of the silt dam is j Indicates the first selected construction site of the silt dam j evaluation indicators, It indicates the total number of evaluation indicators in the preliminary selection of construction sites for check dams; No. i The first site of the preliminary selection of the construction site of the silt dam j The second decision value of the evaluation index is obtained by The weight coefficient of the evaluation index is The first soil material site to be evaluated It is obtained by multiplying the first decision values ​​of the evaluation indicators.

[0047] Step 6: Calculate the evaluation coefficient of each preliminary selected construction site of the silt dam respectively, and select the preliminary selected construction site of the silt dam with the largest evaluation coefficient as the selected site; The calculation formula for the evaluation coefficient of the preliminary construction site of the silt dam is as follows: , in, Indicates i The evaluation coefficient of the preliminary selection of the construction site of the silt dam, Indicates i The Euclidean distance between the initial construction site of the silt dam and the negative ideal vector of the second decision matrix, Indicates i The Euclidean distance between the initial construction site of the silt dam and the positive ideal vector of the second decision matrix.

[0048] The dam site selection evaluation index data in the embodiment of the present invention is shown in Table 1: Table 1 Evaluation index data for dam site selection

[0049] The weight coefficients of the evaluation indicators in the dam site selection evaluation indicator data in the embodiment of the present invention are as follows: 0.06, 0.09, 0.11, 0.1, 0.08, 0.07, 0.05, 0.04, 0.17, 0.15, 0.04, 0.04; The Euclidean distances between the preliminary selected construction sites of the silt dam in the embodiment of the present invention and the positive ideal vectors and negative ideal vectors of the second decision matrix, and the evaluation coefficients of the preliminary selected construction sites of the silt dam are shown in Table 2: Table 2 Evaluation coefficients of preliminary selection of construction sites for silt dams

Claims

1. The precise site selection method for silt dam project is characterized by: The following steps are involved: Step 1: Select several preliminary construction sites for silt dams based on the river basin planning; Step 2: Collect the evaluation index data of the dam site selection of the preliminary selected construction sites of the silt dam respectively, and use the expert scoring to determine the weight coefficient of each evaluation index in the dam site selection evaluation index data; Step 3: Processing the evaluation index data of the dam site selection by the range normal method to obtain the first decision matrix of the evaluation index, and calculating the second decision matrix by the first decision matrix and the weight coefficient; Step 4: Determine the positive ideal vector and the negative ideal vector of the second decision matrix of the evaluation index; Step 5: Calculate the Euclidean distance between the evaluation index and the positive ideal vector and the negative ideal vector of the second decision matrix respectively; Step 6: Calculate the evaluation coefficient of each preliminary selected construction site of the silt dam respectively, and select the preliminary selected construction site of the silt dam with the largest evaluation coefficient as the selected site.

2. The precise site selection method for a silt dam project according to claim 1 is characterized in that: The number of preliminary selected construction sites for the silt dam is no less than 3; The evaluation index data for dam site selection include the following evaluation indexes: maximum dam height u1 of the silt dam, maximum thickness of the loess layer at the dam foundation u2, thickness of collapsible loess at the foundation surface u3, elevation difference between the top surface of the useful layer of the material field and the dam top u4, sunshine duration at the transfer field u5, distance between the material field and the transfer field u6, distance between the silt dam and the transfer field u7, difference between the natural moisture content of the material field and the optimal moisture content u8, degree of dispersion of soil materials at the material field u9, sand interception storage capacity u10, and the maximum value of the dam site selection evaluation index data. 10 , flooded cultivated land area 11 、Number of immigrants relocated 12 .

3. The precise site selection method for a silt dam project according to claim 2 is characterized in that: The maximum dam height u1 of the silt dam is the maximum dam height of the silt dam to be constructed at the preliminary selected construction site of the silt dam; the maximum dam height u1 of the silt dam is a negative indicator and a low-optimal indicator; The maximum thickness u2 of the loess layer at the dam foundation is the maximum thickness of the loess layer at the dam foundation on the dam axis section of the silt dam to be constructed at the preliminary selected construction site of the silt dam; the maximum thickness u2 of the loess layer at the dam foundation is a negative indicator and a low-quality indicator; The collapsible loess thickness u3 of the foundation surface is the maximum thickness of medium and above collapsible loess or self-weight collapsible loess on the foundation surface of the silt dam on the dam axis section of the silt dam to be built at the preliminary construction site of the silt dam; the collapsible loess thickness u3 of the foundation surface is a negative indicator and a low-quality indicator; The elevation difference u4 between the top surface of the useful layer of the material yard and the dam crest is the elevation difference between the crest of the silt dam to be built at the preliminary construction address of the silt dam and the top surface of the useful layer of the main earth material yard of the silt dam; the elevation difference u4 between the top surface of the useful layer of the material yard and the dam crest is a negative indicator and a low-quality indicator.

4. The precise site selection method for a silt dam project according to claim 3 is characterized in that: The sunshine duration u5 of the transfer yard is the sunshine duration on the spring equinox day of the soil material construction transfer yard of the silt dam to be built at the preliminary construction site of the silt dam; the sunshine duration u5 of the transfer yard is a positive indicator and a high-quality indicator; The distance u6 between the material yard and the transfer yard is the straight-line distance from the plane centroid of the earth material yard of the silt dam to be constructed at the preliminary construction address of the silt dam to the plane centroid of the construction transfer yard; the distance u6 between the material yard and the transfer yard is a negative indicator and a low-optimal indicator; The distance u7 between the silt dam and the transfer yard is the straight-line distance from the midpoint of the dam axis of the silt dam to be constructed at the preliminary construction site of the silt dam to the centroid of the plane of the construction transfer yard; the distance u7 between the silt dam and the transfer yard is a negative indicator and a low-optimal indicator; The difference u8 between the natural moisture content of the material yard and the optimal moisture content is the difference between the natural moisture content of the soil material yard for the silt dam to be built at the preliminary construction site of the silt dam and the optimal moisture content of the soil itself; the difference u8 between the natural moisture content of the material yard and the optimal moisture content is a negative indicator and a low-quality indicator.

5. The precise site selection method for a silt dam project according to claim 4 is characterized in that: The dispersion degree u9 of the soil material in the material field is the product of the dispersion degree D of the soil material field of the silt dam to be constructed at the preliminary construction site of the silt dam and the processing difficulty coefficient K; the dispersion degree u9 of the soil material in the material field is a negative indicator and a low-quality indicator; The calculation formula of the dispersion degree D of the earth material field for the silt dam to be constructed is as follows: in, Indicates the dispersion of the soil material field of the silt dam to be built at the preliminary construction site of the silt dam, It indicates the content of colloid or clay in the soil material of the soil material field of the silt dam to be built at the preliminary construction site of the silt dam measured by the unconventional densitometer test. It refers to the content of colloid particles or clay particles in the soil material of the soil material field where the silt dam is to be constructed at the preliminary construction site of the silt dam as measured by conventional densitometer test; The value of the processing difficulty coefficient K of the soil material field for the silt dam to be built is as follows: if the soil material of the soil material field for the silt dam to be built is non-dispersed soil, the value of the processing difficulty coefficient K is 1; if the soil material of the soil material field for the silt dam to be built is transitional soil, the value of the processing difficulty coefficient K is 1.5; if the soil material of the soil material field for the silt dam to be built is physically dispersed soil, the value of the processing difficulty coefficient K is 2; if the soil material of the soil material field for the silt dam to be built is chemically dispersed soil, the value of the processing difficulty coefficient K is 2.5; if the soil material of the soil material field for the silt dam to be built is physically-chemically dispersed soil, the value of the processing difficulty coefficient K is 3; The sediment retention capacity u 10 is the accumulated sedimentation volume of the silt dam to be constructed at the preliminary selected construction site after reaching the designed sedimentation period; the sediment retention capacity u 10 It is a positive indicator and a high-quality indicator; The designed sedimentation period is determined according to the river basin planning. If the designed sedimentation period is not determined in the river basin planning, the designed sedimentation period is 30 years for the small or medium-sized sedimentation dam to be built, and 50 years for the large-scale sedimentation dam to be built. The flooded cultivated land area u 11 It is the sum of all cultivated land areas in the area below the normal water level of the silt dam to be built and the temporary flooded area above the normal water level of the reservoir at the preliminary construction site of the silt dam; the flooded cultivated land area u 11 It is a negative indicator and a low-quality indicator; The number of immigrants relocated u 12 The number of immigrants who need to be relocated and resettled within the scope of land acquisition for the construction of the silt dam at the preliminary selected construction site; the number of immigrants to be relocated u 12 It is a negative indicator and a low-quality indicator.

6. The precise site selection method for a silt dam project according to claim 1 is characterized in that: The experts participating in the expert scoring are persons with the professional title of senior engineer or above in the design of water conservancy projects or water conservation projects. The number of experts participating in the expert scoring meets the following requirements: no less than 3 people when the silt dam to be built is a small water conservancy project, no less than 5 people when the silt dam to be built is a medium-sized water conservancy project, and no less than 7 people when the silt dam to be built is a large water conservancy project; the number of experts participating in the expert scoring who belong to the area where the project is constructed shall not be less than 30% of the total number of experts participating in the scoring; The sum of the weight coefficients of the evaluation indicators is 100%; the weight coefficient of each evaluation indicator is not less than 3% and not more than 20%. If the weight coefficient of each evaluation indicator is less than 3% or greater than 20%, an additional expert will be added to re-determine the weight coefficient of each evaluation indicator in the dam site selection evaluation indicator data.

7. The precise site selection method for a silt dam project according to claim 1 is characterized in that: The first decision matrix of the evaluation index is obtained in the following way: X=(x ij )m×12 ， in, X Represents the first decision matrix of the evaluation index, x ij Indicates i The first site of the preliminary selection of the construction site of the silt dam j The first decision value of the evaluation index, It indicates the number of preliminary selected construction sites for check dams; If the evaluation index is a high-quality index, the calculation formula for the first decision value of the evaluation index is as follows: in, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The first decision value of the evaluation index, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The basic value of the evaluation index, The first one indicates the preliminary construction site of the silt dam. j The minimum value among the basic values ​​of the evaluation indicators, The first one indicates the preliminary construction site of the silt dam. j The maximum value among the basic values ​​of the evaluation indicators, It indicates the number of preliminary selected construction sites for check dams; If the evaluation index is a high-quality index, the calculation formula for the first decision value of the evaluation index is as follows: in, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The first decision value of the evaluation index, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The basic value of the evaluation index, The first one indicates the preliminary construction site of the silt dam. j The minimum value among the basic values ​​of the evaluation indicators, The first one indicates the preliminary construction site of the silt dam. j The maximum value among the basic values ​​of the evaluation indicators, Indicates the number of preliminary selected construction sites for check dams.

8. The precise site selection method for a silt dam project according to claim 1 is characterized in that: The calculation formula of the positive ideal vector is as follows: ， in, represents the positive ideal vector of the evaluation index, The maximum value of the second decision value of the first evaluation index for the preliminary selection of the construction site of the silt dam, The maximum value of the second decision value of the second evaluation index for the preliminary selection of the construction site of the silt dam, The maximum value among the second decision values ​​of the twelfth evaluation index of the preliminary selection of the construction site of the silt dam; The calculation formula of the negative ideal vector is as follows: ， in, represents the negative ideal vector of the evaluation index, The minimum value of the second decision value of the first evaluation index for the preliminary selection of the construction site of the silt dam, represents the minimum value of the second decision value of the second evaluation index for the preliminary selection of the construction site of the silt dam, It represents the minimum value among the second decision values ​​of the twelfth evaluation indicator for the preliminary selection of the construction site of the silt dam.

9. The precise site selection method for a silt dam project according to claim 1 is characterized in that: The calculation formula of the Euclidean distance between the evaluation index and the positive ideal vector of the second decision matrix is ​​as follows: in, Indicates i The Euclidean distance between each evaluation index of the preliminary construction site of the silt dam and the positive ideal vector of the second decision matrix, The first one indicates the preliminary construction site of the silt dam. j The maximum value of the second decision values ​​of the evaluation indicators, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The second decision value of the evaluation index, i Indicates i The preliminary construction site of the silt dam is j Indicates the first selected construction site of the silt dam j evaluation indicators, It indicates the total number of evaluation indicators in the preliminary selection of construction sites for check dams; The calculation formula of the Euclidean distance between the evaluation index and the negative ideal vector of the second decision matrix is ​​as follows: in, Indicates i The Euclidean distance between each evaluation index of the preliminary construction site of the silt dam and the negative ideal vector of the second decision matrix, The first one indicates the preliminary construction site of the silt dam. j The minimum value of the second decision value of the evaluation index, Indicates i The first site of the preliminary selection of the construction site of the silt dam j The second decision value of the evaluation index, i Indicates i The preliminary construction site of the silt dam is j Indicates the first selected construction site of the silt dam j evaluation indicators, It indicates the total number of evaluation indicators in the preliminary selection of construction sites for check dams; The said i The first site of the preliminary selection of the construction site of the silt dam j The second decision value of the evaluation index is obtained by The weight coefficient of the evaluation index is The first soil material site to be evaluated It is obtained by multiplying the first decision values ​​of the evaluation indicators.

10. The precise site selection method for a silt dam project according to claim 1 is characterized in that: The calculation formula of the evaluation coefficient of the preliminary selection of the construction site of the silt dam is as follows: ， in, Indicates i The evaluation coefficient of the preliminary selection of the construction site of the silt dam, Indicates i The Euclidean distance between the initial construction site of the silt dam and the negative ideal vector of the second decision matrix, Indicates i The Euclidean distance between the initial construction site of the silt dam and the positive ideal vector of the second decision matrix.

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