Method for evaluating adaptability of water delivery pipeline in mountain city

Abstract

The invention provides a mountain city water delivery pipeline adaptability evaluation method, which comprises the following steps: firstly, constructing an adaptability comprehensive evaluation index system based on an analytic hierarchy process according to each factor index influencing a long-distance large-caliber water delivery pipeline project, and then on the basis of project original data, respectively adopting the analytic hierarchy process and an entropy weight method to evaluate the adaptability of a long-distance large-caliber water delivery pipeline project. And respectively analyzing the qualitative evaluation weight and entropy weight of each factor index of the water conveying pipeline as a qualitative index and a quantitative index of evaluation, and finally performing comprehensive adaptability evaluation on the pipeline by combining the qualitative index and the quantitative index so as to perform preferential selection of the pipe of the water conveying pipeline according to an adaptability evaluation result. According to the method, the qualitative indexes and the quantitative indexes are comprehensively considered to obtain the comprehensive weight, errors caused by subjective and objective factors are reduced, the evaluation result is more scientific and reasonable, and reasonable preferential recommendation can be more comprehensively and scientifically provided for pipe selection of the water conveying pipeline in the mountain city water conveying project.

Description

Technical Field

[0001] The invention belongs to the technical field of water network construction and application, and in particular relates to an adaptability evaluation method for water pipelines in mountainous cities. Background Art

[0002] Building a national water network is an inevitable requirement to solve the uneven distribution of water resources in time and space and achieve a larger range of spatial balance. It is imperative to build long-distance and large-diameter water transmission projects. In large-diameter and long-distance water transmission projects, pipe investment is usually 70% to 80% of the investment in water transmission pipeline projects. Pipes have a significant impact on project investment, safety, construction and maintenance. Therefore, high safety requirements, good economy and simple construction technology are one of the key points that must be considered when selecting pipes.

[0003] In mountainous urban water supply projects, pipes with a diameter of DN1200 or above are usually called large-diameter pipes. The pipes used in large-diameter long-distance water supply projects mainly include prestressed steel cylinder concrete pipes (PCCP), steel pipes (SP), ductile iron pipes (DIP) and glass fiber reinforced plastic sand-filled pipes (RPMP). In current practical engineering applications, in the selection of large-diameter water supply pipes, experience or expert scoring is usually relied on to judge the quality of each pipe, or the comparison of parameters of individual qualitative indicators is relied on to determine the quality of each pipe, and the pipes are selected based on merit. However, these methods have strong subjective dependence, and the evaluation results are easily affected by decision makers. The parameter selection of qualitative indicators also focuses on certain individual solutions, which lacks comprehensiveness and scientificity.

[0004] Therefore, how to establish a more comprehensive, scientific and reasonable evaluation and selection scheme for the adaptability selection of water pipelines in mountainous urban water supply projects has become a problem that needs to be solved. Summary of the invention

[0005] In view of the above-mentioned deficiencies of the prior art, the present invention provides a method for evaluating the adaptability of water pipelines in mountainous cities, so as to provide more comprehensive and scientific rational recommendations for the selection of pipe materials for water pipelines in water supply projects in mountainous cities.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A method for evaluating the adaptability of a water pipeline in a mountainous city comprises the following steps:

[0008] S1. Based on the analytic hierarchy process, a comprehensive evaluation index system for the adaptability of water pipelines is established;

[0009] S2. Based on the adaptability comprehensive evaluation index system of the water pipeline, a judgment matrix of different hierarchical structures in the adaptability comprehensive evaluation index system is established by using the hierarchical analysis method to calculate the qualitative evaluation weight of the water pipeline in each factor index;

[0010] S3. Based on the comprehensive evaluation index system of the adaptability of the water pipeline, the entropy weight method is used to calculate the entropy weight of each factor index of the water pipeline;

[0011] S4. Calculate the comprehensive weight value of each factor index of the water pipeline by combining the qualitative evaluation weight and entropy weight;

[0012] S5. Based on the comprehensive weight value of each factor index, the adaptability of the alternative water pipelines with different pipe materials is evaluated to obtain the adaptability evaluation results of the water pipelines.

[0013] Specifically, in step S1, the adaptability comprehensive evaluation index system includes an index hierarchy model for the comprehensive evaluation of adaptability of the water pipeline, the bottom layer of the index hierarchy model is a sub-criteria layer, and the sub-criteria layer includes multiple factor indicators for evaluating the adaptability performance of the water pipeline.

[0014] Specifically, the index hierarchy model includes a target layer, a criterion layer and a sub-criterion layer from top to bottom; the target layer takes the maximum comprehensive adaptability as the decision-making target; the criterion layer includes comprehensive cost factors, safety factors and construction adaptability factors;

[0015] The factor indicators of the sub-criteria layer of the comprehensive cost factor include operation and maintenance costs, installation costs, pipe material costs and pipeline roughness;

[0016] The factor indicators of the sub-criteria layer of the safety factor include water hammer resistance, corrosion resistance, high pressure resistance, negative pressure resistance and service life;

[0017] The factor indicators of the sub-criteria layer of the construction adaptability factor include terrain adaptability, maintenance difficulty and installation complexity.

[0018] Specifically, in step S2, the judgment matrix A of the criterion layer in the adaptability comprehensive evaluation index system is expressed as:

[0019]

[0020] Among them, a ij represents the scale value of the i-th factor relative to the j-th factor in the criterion layer of the adaptability comprehensive evaluation index system, and a ij ×a ji =1; m is the number of factor dimensions contained in the criterion layer of the adaptability comprehensive evaluation index system;

[0021] The judgment matrix B of the sub-criteria layer of the i-th factor in the adaptability comprehensive evaluation index system i It is expressed as:

[0022]

[0023] Among them, b i,kl It represents the scale value of the kth factor index in the sub-criteria layer of the i-th factor in the adaptability comprehensive evaluation index system relative to the l-th factor index, and b i,kl ×b i,lk =1; n is the number of factor indicator dimensions contained in the sub-criteria layer of the i-th factor in the adaptability comprehensive evaluation index system.

[0024] Specifically, in step S2, the specific method for calculating the qualitative evaluation weight of the water pipeline in each factor index is:

[0025] S201, calculating the weight of each factor in the criterion layer based on the judgment matrix of the criterion layer:

[0026]

[0027] In the formula, The eigenvector of the i-th factor in the criterion layer is the m-th root of the product of the i-th row elements in the judgment matrix A of the criterion layer; W i represents the weight of the i-th factor in the criterion layer;

[0028] S202, calculating the sub-weight of each factor index in the sub-criteria layer of each factor based on the judgment matrix of the sub-criteria layer:

[0029]

[0030] In the formula, The characteristic vector of the kth factor index in the sub-criteria layer of the i-th factor is the judgment matrix B of the sub-criteria layer of the i-th factor. i The nth root of the product of the elements in the kth row; W i,k represents the sub-weight of the k-th factor indicator in the sub-criteria layer of the i-th factor;

[0031] S203, based on the weight of each factor in the criterion layer and the sub-weight of each factor indicator in the sub-criterion layer, calculate the qualitative evaluation weight of each factor indicator in the sub-criterion layer:

[0032] [W i,k ]=W i ×W i,k ;

[0033] In the formula, [W i,k ] represents the qualitative evaluation weight of the kth factor indicator in the sub-criteria layer of the i-th factor.

[0034] Specifically, in step S202, for any i-th factor, the sub-weights W of the various factor indicators in the sub-criteria layer of the factor are calculated. i,k After that, the corresponding consistency ratio CR needs to be calculated.i And perform consistency verification; if CR i ≤0.1, the consistency test is considered to have passed, and the sub-weight W is retained. i,k The calculation result; if CR i >0.1, it is considered that the consistency test has not passed, and the judgment matrix B of the sub-criteria layer of the i-th factor needs to be i After adjusting the scale value in, recalculate until it passes the consistency test.

[0035] Specifically, the consistency ratio CR i The calculation method is:

[0036]

[0037] In the formula, CI i is the consistency index of the i-th factor; RI is the average random consistency index of the sub-criteria layer, where:

[0038]

[0039] In the formula, λ i,max is the judgment matrix B of the sub-criteria layer of the i-th factor i The largest characteristic root of i ] is the qualitative evaluation weight of each factor index in the sub-criteria layer of the i-th factor [W i,k ] is a qualitative evaluation weight vector; {B i [W i ]} k Represents the judgment matrix B i and the qualitative evaluation weight vector [W i ]The resulting vector B i [W i ] is the kth component in the adaptive comprehensive evaluation index system; n is the number of factor indicator dimensions contained in the sub-criteria layer of the i-th factor in the adaptive comprehensive evaluation index system.

[0040] Specifically, step S3 is as follows:

[0041] S301, quantifying and normalizing each factor index in the sub-criteria layer of the comprehensive evaluation index system of suitability of each candidate water pipeline, and obtaining the normalized index value of each factor index of each water pipeline;

[0042] S302, calculating the entropy weight of each factor index of the water pipeline in the following manner:

[0043]

[0044] in,

[0045] g q=1-e q ;

[0046]

[0047]

[0048] In the formula, w q is the entropy weight of the water pipeline in the qth factor index; P pq is the proportion of the normalized index value of the pth water pipeline selected under the qth factor index; X pq is the normalized index value of the qth factor index of the pth alternative water pipeline; e q is the scalar entropy value of the qth factor index; g q is the difference coefficient of the qth factor index; p = 1, 2, ..., M, M is the number of alternative water pipeline types; q = 1, 2, ..., N, N is the number of all factor indicators contained in the sub-criteria layer in the adaptability comprehensive evaluation index system.

[0049] Specifically, in step S4, the specific method for calculating the comprehensive weight value of the water pipeline in each factor index is: one-to-one correspondence is made between the qualitative evaluation weight and the entropy weight of each factor index contained in the sub-criteria layer in the adaptability comprehensive evaluation index system, and then the comprehensive weight value of the water pipeline in each factor index is calculated according to the following formula:

[0050] W zq =α[W q ]+(1-α)w q ;

[0051] Where W zq is the comprehensive weight value of the water pipeline in the qth factor index; [W q ]、w q They respectively represent the qualitative evaluation weight and entropy weight of the qth factor indicator, q=1, 2, ..., N, N is the number of all factor indicators contained in the sub-criteria layer in the adaptability comprehensive evaluation indicator system; α is the preset resolution coefficient.

[0052] Specifically, in step S5, the specific method of evaluating the adaptability of the candidate water pipelines of different pipe materials based on the comprehensive weight value of each factor index is as follows:

[0053] Calculate the adaptability evaluation scores of alternative water pipelines with different pipe materials:

[0054]

[0055] Among them, Z prepresents the adaptability evaluation score of the pth alternative water pipeline, and the water pipeline with the highest adaptability evaluation score is identified as the most preferred water pipeline among the alternatives; W zq is the comprehensive weight value of the water pipeline in the qth factor index; X pq is the normalized index value of the pth alternative water pipeline in the qth factor index; p = 1, 2, ..., M, M is the number of alternative water pipeline types; q = 1, 2, ..., N, N is the number of all factor indicators contained in the sub-criteria layer in the adaptability comprehensive evaluation index system.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] 1. For long-distance and large-diameter water pipelines, this invention proposes for the first time a new method for evaluating the adaptability of water pipelines based on the analytic hierarchy process and the entropy weight method. The adaptability evaluation of water pipelines is divided into multiple levels and factors, and the relative importance of each factor is determined by the analytic hierarchy process and the entropy weight method. The qualitative and quantitative indicators are combined to comprehensively evaluate the adaptability of water pipeline materials, providing a quantifiable scientific basis for the selection of water pipeline materials. This method can also provide a reference for the selection of pipe materials for other similar long-distance and large-diameter water pipeline projects.

[0058] 2. The adaptability evaluation method for mountainous urban water pipelines of the present invention was applied to a long-distance and large-diameter water pipeline project in the southwest. The results showed that PCCP pipes had the highest score and the best comprehensive performance, and were the preferred main water pipeline materials for this project. Steel pipe materials were used for some pipelines that passed through special areas such as rivers and swamps and areas with complex terrain. This material selection scheme can ensure the safety, economy, and convenience of operation and maintenance of the water pipeline project.

[0059] 3. Based on the adaptability evaluation method for water pipelines in mountainous cities of the present invention, a set of visualization calculation systems is also designed, covering the results of analytic hierarchy process, entropy weight method and comprehensive weight calculation, and performing comprehensive score calculation and analysis on each pipeline material, thus realizing the adaptability evaluation and visualization rapid calculation of long-distance and large-diameter water pipelines, proving that the method of the present invention has good technical application value.

[0060] In summary, the method of the present invention comprehensively considers qualitative indicators and quantitative indicators to obtain comprehensive weights, reduces errors caused by subjective and objective factors, makes the evaluation results more scientific and reasonable, and can provide more comprehensive and scientific rational recommendations for the selection of pipe materials for water pipelines in mountainous urban water supply projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to make the purpose, technical solution and advantages of the invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings, in which:

[0062] Figure 1It is a flow chart of the adaptability evaluation method of the water pipeline in mountainous cities of the present invention;

[0063] Figure 2 It is a schematic diagram of the index hierarchy model framework in the adaptability comprehensive evaluation index system of the present invention;

[0064] Figure 3 This is an example diagram of the visual interface of the evaluation software system implemented by the adaptability evaluation method for water pipelines in mountainous cities of the present invention in the embodiment. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but only represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0066] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0067] 1.1 Technical route of the adaptability evaluation method of water pipelines in mountainous cities

[0068] like Figure 1 As shown, the adaptability evaluation method for water pipelines in mountainous cities provided by the present invention comprises the following steps:

[0069] S1. Based on the analytic hierarchy process, a comprehensive evaluation index system for the adaptability of water pipelines is established;

[0070] S2. Based on the adaptability comprehensive evaluation index system of the water pipeline, a judgment matrix of different hierarchical structures in the adaptability comprehensive evaluation index system is established by using the hierarchical analysis method to calculate the qualitative evaluation weight of the water pipeline in each factor index;

[0071] S3. Based on the comprehensive evaluation index system of the adaptability of the water pipeline, the entropy weight method is used to calculate the entropy weight of each factor index of the water pipeline;

[0072] S4. Calculate the comprehensive weight value of each factor index of the water pipeline by combining the qualitative evaluation weight and entropy weight;

[0073] S5. Based on the comprehensive weight value of each factor index, the adaptability of the alternative water pipelines with different pipe materials is evaluated to obtain the adaptability evaluation results of the water pipelines.

[0074] The present invention provides a method for evaluating the adaptability of a water pipeline in a mountainous city. The method first constructs an adaptability comprehensive evaluation index system based on the analytic hierarchy process according to various factor indicators that affect a long-distance and large-diameter water pipeline project. Then, based on the original data of the project, the analytic hierarchy process and the entropy weight method are used to analyze the qualitative evaluation weights and entropy weights of the water pipeline in various factor indicators, respectively, to serve as qualitative indicators and quantitative indicators for evaluation. Finally, a comprehensive adaptability evaluation is performed relative to the pipeline in combination with the qualitative indicators and the quantitative indicators, to select the best pipe material for the water pipeline according to the adaptability evaluation results. The method comprehensively considers the qualitative indicators and the quantitative indicators to obtain the comprehensive weight, reduces the error caused by subjective and objective factors, makes the evaluation result more scientific and reasonable, and can provide a more comprehensive and scientific rational recommendation for the selection of pipe materials for the water pipeline in the water pipeline project in the mountainous city.

[0075] 1.2 Construction of adaptability comprehensive evaluation index system

[0076] The pipes commonly used in long-distance and large-diameter water supply projects mainly include prestressed steel cylinder concrete pipe (PCCP), steel pipe (SP), ductile iron pipe (DIP), and glass fiber reinforced plastic composite pipe (RPMP). In step S1 of the present invention, all factors affecting the pipeline are comprehensively considered, and various factor indicators of the comprehensive evaluation of the adaptability of the water supply pipeline are included. The hierarchical analysis method is used to establish an indicator hierarchy model in the comprehensive evaluation index system of the adaptability of the water supply pipeline. The indicator hierarchy model includes a target layer, a criterion layer, and a sub-criterion layer from top to bottom. The sub-criterion layer is the bottom layer, which includes various factor indicators used to evaluate the adaptability performance of the water supply pipeline.

[0077] Specifically, as a preferred embodiment, Figure 2 As shown in the figure, in the indicator hierarchy model, the target layer takes the maximum comprehensive adaptability as the decision-making target; the criterion layer includes comprehensive cost factors, safety factors and construction adaptability factors; the factor indicators of the sub-criterion layer of the comprehensive cost factor include operation and maintenance costs, installation costs, pipe material costs and pipeline roughness; the factor indicators of the sub-criterion layer of the safety factor include water hammer resistance, corrosion resistance, high pressure resistance, negative pressure resistance and service life; the factor indicators of the sub-criterion layer of the construction adaptability factor include terrain adaptability, maintenance difficulty and installation complexity.

[0078] 1.3 Qualitative evaluation of various factors of water pipelines

[0079] In step S2 of the present invention, the analytic hierarchy process is used as a qualitative analysis method for various factor indicators of the water pipeline, and the specific steps are:

[0080] ①Use the hierarchical analysis method to establish the judgment matrix of different hierarchical structures in the adaptability comprehensive evaluation index system.

[0081] Here we need to construct the judgment matrix of the criterion layer and the sub-criterion layer in the adaptability comprehensive evaluation index system respectively, where the judgment matrix A of the criterion layer is expressed as:

[0082]

[0083] Among them, a ij represents the scale value of the i-th factor relative to the j-th factor in the criterion layer of the adaptability comprehensive evaluation index system, and a ij ×a ji =1; m is the number of factor dimensions contained in the criterion layer of the adaptability comprehensive evaluation index system;

[0084] The judgment matrix B of the sub-criteria layer of the i-th factor is i It is expressed as:

[0085]

[0086] Among them, b i，kl It represents the scale value of the kth factor index in the sub-criteria layer of the i-th factor in the adaptability comprehensive evaluation index system relative to the l-th factor index, and b i，kl ×b i，lk =1; n is the number of factor indicator dimensions contained in the sub-criteria layer of the i-th factor in the adaptability comprehensive evaluation index system.

[0087] When determining the values ​​of the scale values ​​in each judgment matrix, Santy's 1-9 scale method can be used for assignment, as shown in Table 1 below.

[0088] Table 1 Santy's 1-9 scale method

[0089]

[0090] ② Use the geometric mean method to calculate the weight of each factor index in the judgment matrix, and then obtain the qualitative evaluation weight of the water pipeline in each factor index. The specific method is:

[0091] S201, calculating the weight of each factor in the criterion layer based on the judgment matrix of the criterion layer:

[0092]

[0093] In the formula, The eigenvector of the i-th factor in the criterion layer is the m-th root of the product of the i-th row elements in the judgment matrix A of the criterion layer; W i represents the weight of the i-th factor in the criterion layer;

[0094] S202, calculating the sub-weight of each factor index in the sub-criteria layer of each factor based on the judgment matrix of the sub-criteria layer:

[0095]

[0096] In the formula, The characteristic vector of the kth factor index in the sub-criteria layer of the i-th factor is the judgment matrix B of the sub-criteria layer of the i-th factor. i The nth root of the product of the elements in the kth row; W i，k represents the sub-weight of the k-th factor indicator in the sub-criteria layer of the i-th factor;

[0097] S203, based on the weight of each factor in the criterion layer and the sub-weight of each factor indicator in the sub-criterion layer, calculate the qualitative evaluation weight of each factor indicator in the sub-criterion layer:

[0098] [W i，k ]=W i ×W i，k ; (5)

[0099] In the formula, [W i，k ] represents the qualitative evaluation weight of the kth factor indicator in the sub-criteria layer of the i-th factor.

[0100] Among them, for any i-th factor, the sub-weight W of each factor indicator in the sub-criteria layer of the factor is calculated i，k After that, the corresponding consistency ratio CR needs to be calculated. i And perform consistency verification; if CR i ≤0.1, the consistency test is considered to have passed, and the sub-weight W is retained. i，k The calculation result; if CR i >0.1, it is considered that the consistency test has not passed, and the judgment matrix B of the sub-criteria layer of the i-th factor needs to be i After adjusting the scale value in, recalculate until it passes the consistency test.

[0101] Consistency ratio CR i The calculation method is:

[0102]

[0103] In the formula, CI i is the consistency index of the i-th factor; R is the average random consistency index of the sub-criteria layer; where:

[0104]

[0105] In the formula, λ i，max is the judgment matrix B of the sub-criteria layer of the i-th factor i The largest characteristic root of i ] is the qualitative evaluation weight of each factor index in the sub-criteria layer of the i-th factor [W i，k ] is a qualitative evaluation weight vector; {B i [W i ]} k Represents the judgment matrix B i and the qualitative evaluation weight vector [W i ]The resulting vector B i [W i ] is the kth component in the adaptive comprehensive evaluation index system; n is the number of factor indicator dimensions contained in the sub-criteria layer of the i-th factor in the adaptive comprehensive evaluation index system.

[0106] The value of the average random consistency index R, of the sub-criteria layer is obtained by looking up the standard reference table according to the matrix order of each sub-criteria layer, as shown in Table 2. For example, according to the standard reference table, the sub-criteria layer is located at the third order in the adaptability comprehensive evaluation index system, so the average random consistency index R, of the sub-criteria layer is 0.58.

[0107] Table 2 Consistency Index RI Value Table

[0108]

[0109] 1.4 Quantitative evaluation of various factors of water pipelines

[0110] In step S3 of the present invention, the entropy weight method is used as a quantitative analysis method for various factor indicators of the water pipeline.

[0111] The entropy weight method is a quantitative analysis method. For some qualitative indicators in the evaluation system, such as operation and maintenance costs, water hammer resistance, corrosion resistance, high pressure resistance, negative pressure resistance, terrain adaptability, maintenance difficulty and installation complexity, it is difficult to quantify them with data. They need to be converted into quantitative indicators by certain methods before they can be calculated. The present invention uses fuzzy membership function to quantify them, and adopts a four-level division method, that is, excellent, good, medium and general four levels to evaluate qualitative indicators. The corresponding membership degrees are 0.8, 0.6, 0.4 and 0.2 respectively. The membership function is shown in the following formula:

[0112]

[0113] Where A(x) represents the membership function; x represents the evaluation level of the qualitative index.

[0114] As for the quantifiable indicators such as installation fee, pipe cost, pipeline roughness and service life, they are quantitatively calculated based on the original data of the actual project.

[0115] The normalization of positive indicators is calculated according to formula (9), and the normalization of negative indicators is calculated according to formula (10). The calculation formula is as follows:

[0116]

[0117]

[0118] Where, X pq , X pq They represent the positive normalized index value and negative normalized index value of the p-th water pipeline under the q-th factor index respectively; minx pq 、maxx pq They respectively represent the minimum and maximum values ​​of the normalized index value under the qth factor index.

[0119] Specifically, pipeline roughness and service life are positive indicators, while installation fees and pipe cost are negative indicators. Therefore, the corresponding formulas above are used to calculate the indicator values.

[0120] Based on the above analysis, the various factor indicators of each candidate water pipeline in the sub-criteria layer of the comprehensive evaluation index system are quantified and normalized. After obtaining the normalized index value of each water pipeline in each factor indicator, the entropy weight of the water pipeline in each factor indicator can be calculated according to the following formulas (11) to (14):

[0121]

[0122] in,

[0123] g q =1-e q ; (12)

[0124]

[0125]

[0126] In the formula, w q is the entropy weight of the water pipeline in the qth factor index; P pq is the proportion of the normalized index value of the pth water pipeline selected under the qth factor index; X pq is the normalized index value of the qth factor index of the pth alternative water pipeline; e q is the scalar entropy value of the qth factor index; g qis the difference coefficient of the qth factor index; p = 1, 2, ..., M, M is the number of alternative water pipeline types; q = 1, 2, ..., N, N is the number of all factor indicators contained in the sub-criteria layer in the adaptability comprehensive evaluation index system.

[0127] The proportion of each normalized index value P is obtained by formula (14): pq The normalized index value standardized matrix formed by the combination is denoted as P, which is used as the pipeline basic data table to participate in the calculation of formula (16).

[0128] 1.5 Calculation of the comprehensive weight value of each factor index

[0129] In step S4, considering that the analytic hierarchy process and the entropy weight method have certain limitations individually, the present invention combines the two to obtain the comprehensive weight value of each factor index, taking into account both subjective experience and objective reality. Based on this technical idea, the specific method for calculating the comprehensive weight value of each factor index of the water pipeline in step S4 is:

[0130] The qualitative evaluation weight and entropy weight of each factor index contained in the sub-criteria layer of the adaptability comprehensive evaluation index system are matched one by one, and then the comprehensive weight value of each factor index of the water pipeline is calculated according to the following formula (15):

[0131] W zq =α[W q ]+(1-α)w q ; (15)

[0132] Where W zq is the comprehensive weight value of the water pipeline in the qth factor index; [W q ]、w q They respectively represent the qualitative evaluation weight and entropy weight of the qth factor indicator, q=1,2,...,N, N is the number of all factor indicators contained in the sub-criteria layer in the adaptability comprehensive evaluation index system; α is the preset resolution coefficient.

[0133] In practical applications, the value of the resolution coefficient α can be preset as needed, and is generally set to 0.5.

[0134] 1.6 Results of adaptability evaluation of water pipelines

[0135] In step S5, the specific method of evaluating the adaptability of the candidate water pipelines with different pipe materials based on the comprehensive weight values ​​of various factor indicators is as follows:

[0136] Calculate the adaptability evaluation scores of alternative water pipelines with different pipe materials:

[0137]

[0138] Among them, Z p represents the adaptability evaluation score of the pth alternative water pipeline, and the water pipeline with the highest adaptability evaluation score is identified as the most preferred water pipeline among the alternatives; W zq is the comprehensive weight value of the water pipeline in the qth factor index; P is the normalized index value standardization matrix, P pq ∈P,P pq is the proportion of the normalized index value of the pth alternative water pipeline under the qth factor index; p = 1, 2, ..., M, M is the number of alternative water pipelines; q = 1, 2, ..., N, N is the number of all factor indicators contained in the sub-criteria layer in the adaptability comprehensive evaluation index system.

[0139] Adaptability evaluation score Z p The highest water pipeline is identified as the most preferred water pipeline among the alternatives and can be used as the optimal option for selecting pipes for water supply projects.

[0140] Example

[0141] In order to better illustrate the effect of the present method, the present method is further illustrated by an application case of the present method in optimizing long-distance and large-diameter water pipes in mountainous cities in actual engineering.

[0142] 2.1 Overview of application cases

[0143] The design life of a long-distance large-diameter water pipeline project in the southwest is 50 years. It serves a population of 450,000. The total length of the pipeline is about 44km, and the diameter is DN1400. The new pipeline adopts pressurized gravity flow water delivery throughout the entire line. The maximum working pressure of the pipeline reaches 0.98MPa, and the water delivery scale is 90,000m 3 / day, the earthquake fortification intensity of the project area is 8 degrees, and it is necessary to determine the pipes suitable for long-distance and large-diameter water transmission, with high safety, good economy, good construction adaptability, small head loss and convenient maintenance. After research, the main pipes available are prestressed steel cylinder concrete pipe (PCCP), steel pipe (SP), ductile iron pipe (DIP), and glass reinforced plastic composite pipe (RPMP). Now we conduct an adaptability evaluation to determine the optimal pipe solution.

[0144] 2.2 Adaptability evaluation

[0145] 2.2.1 Calculation of weights in AHP

[0146] A judgment matrix was constructed based on the evaluation system constructed above, and values ​​were assigned according to Santy's 1-9 scaling method and consistency tests were performed. The calculation results are shown in Table 3 below.

[0147] Table 3 Summary of judgment matrix results at the criterion level and sub-criterion level

[0148]

[0149] Therefore, the judgment matrix A of the criterion layer is:

[0150]

[0151] Judgment matrix B of the sub-criteria layer of comprehensive cost factors 1 for:

[0152]

[0153] Judgment matrix B of the sub-criteria layer of safety factors 2 for:

[0154]

[0155] Judgment matrix B of the sub-criteria layer of construction adaptability factors 3 for:

[0156]

[0157] By sorting the levels according to formulas (3) to (5), the qualitative evaluation weights of the various factor indicators in the sub-criteria layer can be obtained. The calculation results are shown in Table 4 below:

[0158] Table 4 Calculation results of qualitative evaluation weights of various factor indicators in the sub-criteria layer

[0159]

[0160] Get the qualitative evaluation weights of each factor indicator, and perform a full sorting set to get the qualitative evaluation weight vector [W]:

[0161] [W]=([W 1 ],[W 2 ],[W 3 ],[W 4 ],[W 5 ],[W 6 ],[W 7 ],[W 8 ],[W 9 ],[W 10 ],[W 11 ],[W 12 ]) T

[0162] =(0.037, 0.037, 0.141, 0.010, 0.101, 0.144, 0.109, 0.083, 0.237, 0.050, 0.020, 0.031) T

[0163] 2.2.2 Entropy weight calculation

[0164] For some indicators in the evaluation system, such as operation and maintenance costs, water hammer resistance, corrosion resistance, high pressure resistance, negative pressure resistance, terrain adaptability, maintenance difficulty and installation complexity, these eight qualitative indicators are difficult to quantify with data and need to be converted into quantitative indicators through certain methods before calculation. This embodiment uses fuzzy membership functions to quantify qualitative indicators.

[0165] This embodiment adopts a four-level classification method, that is, four levels of excellent, good, medium and general are used to evaluate the qualitative indicators, and their corresponding membership degrees are 0.8, 0.6, 0.4 and 0.2 respectively. The specific calculation is calculated according to formula (8). Combined with the actual engineering data, the fuzzy evaluation of the performance of the four pipes is shown in Table 5 below:

[0166] Table 5 Comparison of pipeline performance fuzzy evaluation

[0167]

[0168] Pipe roughness and service life are positive indicators, calculated according to formula (9), installation fee, pipe material cost, etc. are negative indicators, calculated according to formula (10). Based on the normalized results, the entropy value e of each factor index is calculated according to formulas (11) to (14). q , coefficient of variation g q , entropy weight w q , the calculation results are shown in Table 6 below:

[0169] Table 6 Calculation results of the weights of each indicator using the entropy weight method

[0170]

[0171] From the above calculation, we get the entropy weight method index weight vector w:

[0172] w=(w 1 , w 2 , w 3 , w 4 , w 5 , w 6 , w 7 , w 8 , w 9 , w 10 , Bw 11 , w 12 ) T =(0.081, 0.092, 0.089, 0.086, 0.079, 0.083, 0.083, 0.081, 0.078, 0.081, 0.086, 0.079) T .

[0173] 2.2.3 Calculation of comprehensive weight value

[0174] The weights of each indicator calculated by the analytic hierarchy process and entropy weight method are calculated according to formula (15) to obtain the comprehensive weight value. The results are shown in Table 7 below:

[0175] Table 7 Comprehensive weight table

[0176]

[0177] After obtaining the comprehensive weight value, the adaptability evaluation scores of different water pipelines can be calculated according to formula (16). The results are shown in Table 8 below:

[0178] Table 8 Scheme adaptability evaluation score table

[0179]

[0180] As can be seen from the table above, PCCP pipe has the highest adaptability evaluation score of 0.357 points, while steel pipe, ductile iron pipe and FRP composite pipe scored 0.228, 0.218 and 0.197 points respectively. The calculation results show that PCCP pipe has the best comprehensive performance in terms of economic performance, safety performance and construction adaptability. Therefore, PCCP pipe is used as the main pipe material for this water transfer project, and steel pipe materials are used for some pipelines passing through rivers, swamps and other special areas with complex terrain.

[0181] 2.2.4 Visual operation interface design

[0182] This embodiment also combines the adaptability evaluation method with visualization technology, develops relevant software and designs a visual operation interface for the optimization of long-distance and large-diameter water pipes in mountainous cities. Its main interface consists of five parts, namely the run button, the weight of the hierarchical analysis method, the weight of the entropy weight method, the comprehensive weight and the bar chart of the scores of different pipes. When the user executes the run button, the relevant data can be input according to the program requirements to obtain the comprehensive score table of each weight value and each pipeline material. The calculation is fast and simple, and the results are as follows: Figure 3 As shown. Figure 3 It can be seen that PCCP pipe has the highest comprehensive score, followed by steel pipe, which means that PCCP pipe has the best comprehensive performance in terms of economy, safety and construction adaptability. Therefore, PCCP pipe is used as the main pipe material for this water supply project, and steel pipe materials are used for some pipelines passing through rivers, swamps and other special areas with complex terrain. According to the evaluation results of the water supply pipe adaptability evaluation method based on the combination of hierarchical analysis method and entropy weight method, this project has been successfully constructed and operated according to the optimal pipe selection scheme (PCCP pipe is used as the main pipe material), and has achieved good engineering results.

[0183] 4. Conclusion

[0184] ① For long-distance and large-diameter water pipelines, this invention proposes for the first time a new method for evaluating the adaptability of water pipelines based on the analytic hierarchy process and the entropy weight method. The adaptability evaluation of water pipelines is divided into multiple levels and factors, and the analytic hierarchy process and the entropy weight method are used to determine the relative importance of each factor. The qualitative and quantitative indicators are combined to comprehensively evaluate the adaptability of water pipeline materials, providing a quantifiable scientific basis for the selection of water pipeline materials. This method can also provide a reference for the selection of pipe materials for other similar long-distance and large-diameter water pipeline projects.

[0185] ② The adaptability evaluation method for mountainous urban water pipelines of the present invention was applied to a long-distance and large-diameter water pipeline project in the southwest. The results showed that PCCP pipes had the highest score and the best comprehensive performance, and were the preferred main water pipeline materials for this project. Steel pipe materials were used for some pipelines that passed through special areas such as rivers and swamps and places with complex terrain. This material selection scheme can ensure the safety, economy and convenience of operation and maintenance of the water pipeline project.

[0186] ③ Based on the adaptability evaluation method of mountainous urban water pipelines of the present invention, a visualization calculation system is also designed, covering the hierarchical analysis method, entropy weight method and comprehensive weight calculation results, and a comprehensive score calculation and analysis is performed on each pipeline material, realizing the adaptability evaluation of long-distance and large-diameter water pipelines and rapid visualization calculation, proving that the method of the present invention has good technical application value.

[0187] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. A method for evaluating the adaptability of water pipelines in mountainous cities, characterized in that: The following steps are involved: S1. Based on the analytic hierarchy process, a comprehensive evaluation index system for the adaptability of water pipelines is established; S2. Based on the adaptability comprehensive evaluation index system of the water pipeline, a judgment matrix of different hierarchical structures in the adaptability comprehensive evaluation index system is established by using the hierarchical analysis method to calculate the qualitative evaluation weight of the water pipeline in each factor index; S3. Based on the comprehensive evaluation index system of the adaptability of the water pipeline, the entropy weight method is used to calculate the entropy weight of each factor index of the water pipeline; S4. Calculate the comprehensive weight value of each factor index of the water pipeline by combining the qualitative evaluation weight and entropy weight; S5. Based on the comprehensive weight value of each factor index, the adaptability of the alternative water pipelines with different pipe materials is evaluated to obtain the adaptability evaluation results of the water pipelines.

2. The method for evaluating the adaptability of water pipelines in mountainous cities according to claim 1, characterized in that: In step S1, the adaptability comprehensive evaluation index system includes an index hierarchy model for the comprehensive evaluation of adaptability of the water pipeline, the bottom layer of the index hierarchy model is a sub-criteria layer, and the sub-criteria layer includes multiple factor indicators for evaluating the adaptability performance of the water pipeline.

3. The method for evaluating the adaptability of water pipelines in mountainous cities according to claim 2, characterized in that: The index hierarchy model includes a target layer, a criterion layer and a sub-criterion layer from top to bottom; the target layer takes the maximum comprehensive adaptability as the decision-making target; the criterion layer includes comprehensive cost factors, safety factors and construction adaptability factors; The factor indicators of the sub-criteria layer of the comprehensive cost factor include operation and maintenance costs, installation costs, pipe material costs and pipeline roughness; The factor indicators of the sub-criteria layer of the safety factor include water hammer resistance, corrosion resistance, high pressure resistance, negative pressure resistance and service life; The factor indicators of the sub-criteria layer of the construction adaptability factor include terrain adaptability, maintenance difficulty and installation complexity.

4. The method for evaluating the adaptability of water pipelines in mountainous cities according to claim 3, characterized in that: In step S2, the judgment matrix A of the criterion layer in the adaptability comprehensive evaluation index system is expressed as: Among them, a ij represents the scale value of the i-th factor relative to the j-th factor in the criterion layer of the adaptability comprehensive evaluation index system, and a ij ×a ji =1; m is the number of factor dimensions contained in the criterion layer of the adaptability comprehensive evaluation index system; The judgment matrix B of the sub-criteria layer of the i-th factor in the adaptability comprehensive evaluation index system i It is expressed as: Among them, b i,kl It represents the scale value of the kth factor index in the sub-criteria layer of the i-th factor in the adaptability comprehensive evaluation index system relative to the l-th factor index, and b i,kl ×b i,lk =1; n is the number of factor indicator dimensions contained in the sub-criteria layer of the i-th factor in the adaptability comprehensive evaluation index system.

5. The method for evaluating the adaptability of water pipelines in mountainous cities according to claim 4, characterized in that: In step S2, the specific method of calculating the qualitative evaluation weight of the water pipeline in each factor index is: S201, calculating the weight of each factor in the criterion layer based on the judgment matrix of the criterion layer: In the formula, The eigenvector of the i-th factor in the criterion layer is the m-th root of the product of the i-th row elements in the judgment matrix A of the criterion layer; W i represents the weight of the i-th factor in the criterion layer; S202, calculating the sub-weight of each factor index in the sub-criteria layer of each factor based on the judgment matrix of the sub-criteria layer: In the formula, The characteristic vector of the kth factor index in the sub-criteria layer of the i-th factor is the judgment matrix B of the sub-criteria layer of the i-th factor. i The nth root of the product of the elements in the kth row; W i,k represents the sub-weight of the k-th factor indicator in the sub-criteria layer of the i-th factor; S203, based on the weight of each factor in the criterion layer and the sub-weight of each factor indicator in the sub-criterion layer, calculate the qualitative evaluation weight of each factor indicator in the sub-criterion layer: [IN i,k ]=W i ×W i,k ; In the formula, [W i,k ] represents the qualitative evaluation weight of the kth factor indicator in the sub-criteria layer of the i-th factor.

6. The method for evaluating the adaptability of water pipelines in mountainous cities according to claim 5, characterized in that: In step S202, for any i-th factor, the sub-weights W of the various factor indicators in the sub-criteria layer of the factor are calculated. i,k After that, the corresponding consistency ratio CR needs to be calculated. i And perform consistency verification; if CR i ≤0.1, the consistency test is considered to have passed, and the sub-weight W is retained. i,k The calculation result; if CR i >0.1, it is considered that the consistency test has not passed, and the judgment matrix B of the sub-criteria layer of the i-th factor needs to be i After adjusting the scale value in, recalculate until it passes the consistency test.

7. The method for evaluating the adaptability of water pipelines in mountainous cities according to claim 6, characterized in that: The consistency ratio CR i The calculation method is: In the formula, CI i is the consistency index of the i-th factor; RI is the average random consistency index of the sub-criteria layer; where: In the formula, λ i,max is the judgment matrix B of the sub-criteria layer of the i-th factor i The largest characteristic root of i ] is the qualitative evaluation weight of each factor index in the sub-criteria layer of the i-th factor [W i，k ] is a qualitative evaluation weight vector; {B i [W i ]} k Represents the judgment matrix B i and the qualitative evaluation weight vector [W i ]The resulting vector B i [W i ] is the kth component in the adaptive comprehensive evaluation index system; n is the number of factor indicator dimensions contained in the sub-criteria layer of the i-th factor in the adaptive comprehensive evaluation index system.

8. The method for evaluating the adaptability of water pipelines in mountainous cities according to claim 2, characterized in that: Step S3 is specifically as follows: S301, quantifying and normalizing each factor index in the sub-criteria layer of the comprehensive evaluation index system of suitability of each candidate water pipeline, and obtaining the normalized index value of each factor index of each water pipeline; S302, calculating the entropy weight of each factor index of the water pipeline in the following manner: in, g q =1-e q ; In the formula, w q is the entropy weight of the water pipeline in the qth factor index; P pq is the proportion of the normalized index value of the pth water pipeline selected under the qth factor index; X pq is the normalized index value of the qth factor index of the pth alternative water pipeline; e q is the scalar entropy value of the qth factor index; g q is the difference coefficient of the qth factor index; p = 1, 2, ..., M, M is the number of alternative water pipeline types; q = 1, 2, ..., N, N is the number of all factor indicators contained in the sub-criteria layer in the adaptability comprehensive evaluation index system.

9. The method for evaluating the adaptability of water pipelines in mountainous cities according to claim 2, characterized in that: In step S4, the specific method of calculating the comprehensive weight value of the water pipeline in each factor index is: one-to-one correspondence between the qualitative evaluation weight and the entropy weight of each factor index contained in the sub-criteria layer in the adaptability comprehensive evaluation index system, and then calculating the comprehensive weight value of the water pipeline in each factor index according to the following formula: W zq =α[W q ]+(1-α)w q ; Where W zq is the comprehensive weight value of the water pipeline in the qth factor index; [W q ]、w q They respectively represent the qualitative evaluation weight and entropy weight of the qth factor indicator, q=1, 2, ..., N, N is the number of all factor indicators contained in the sub-criteria layer in the adaptability comprehensive evaluation indicator system; α is the preset resolution coefficient.

10. The method for evaluating the adaptability of water pipelines in mountainous cities according to claim 2, characterized in that: In step S5, the specific method of evaluating the adaptability of the candidate water pipelines with different pipe materials based on the comprehensive weight values ​​of various factor indicators is as follows: Calculate the adaptability evaluation scores of alternative water pipelines with different pipe materials: Among them, Z p represents the adaptability evaluation score of the pth alternative water pipeline, and the water pipeline with the highest adaptability evaluation score is identified as the most preferred water pipeline among the alternatives; W zq is the comprehensive weight value of the water pipeline in the qth factor index; P is the normalized index value standardization matrix, P pq ∈P,P pq is the proportion of the normalized index value of the pth alternative water pipeline under the qth factor index; p = 1, 2, ..., M, M is the number of alternative water pipelines; q = 1, 2, ..., N, N is the number of all factor indicators contained in the sub-criteria layer in the adaptability comprehensive evaluation index system.

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