Urban underground comprehensive pipe gallery gas pipeline risk assessment method

Abstract

The invention discloses an urban underground comprehensive pipe gallery gas pipeline risk assessment method. The method comprises the following steps: determining the possibility of an accident of an urban underground comprehensive pipe gallery gas pipeline; calculating the vulnerability of the gas pipeline of the utility tunnel; calculating and determining the accident consequence severity of the urban underground comprehensive pipe gallery gas pipeline through the accident consequence severity and the accident prevention capability; calculating a risk score of the urban underground comprehensive pipe gallery gas pipeline based on the possibility of the accident of the urban underground comprehensive pipe gallery gas pipeline, the vulnerability of the comprehensive pipe gallery gas pipeline and the severity of the accident consequence; and according to the urban underground comprehensive pipe gallery gas pipeline risk score, the urban underground comprehensive pipe gallery gas pipeline risk grade is determined, and a corresponding disposal method is adopted. The risk assessment index system established by the method is more systematic, comprehensive, comprehensive and reasonable, and the risk value and the risk level of the assessed pipeline can be obtained through simple calculation.

Description

Technical Field

[0001] The invention relates to a risk assessment method, and in particular to a risk assessment method for gas pipelines in urban underground integrated pipe galleries. Background Art

[0002] Urban gas pipelines are affected by their own properties, medium characteristics and management and scheduling, and there is a risk of leakage during operation. As for the safety risk assessment of gas pipelines, they are mainly conceptual, principled and guiding, and have not been refined to the specific operational level. There is a lack of professional and operational risk assessment methods.

[0003] The Chinese patent with publication number: CN118536405A and application date of July 19, 2024 discloses "a method and device for gas pipeline risk assessment, and a computer-readable storage medium". The pipeline characteristic value passes through the input layer, hidden layer, gated activation unit, and output layer of the gated pixel convolutional neural network in sequence to obtain the pipeline risk level; the method includes: obtaining a second candidate signal according to the first candidate signal and the gated signal; obtaining a third candidate signal according to the second candidate signal and the hyperbolic tangent function; obtaining the output of the gated activation unit according to the third candidate signal and the gated signal; wherein the first candidate signal is obtained by the candidate convolution layer and the hyperbolic tangent function, the gated signal is obtained by the gated convolution layer and the sigmiod function, and the candidate convolution layer and the gated convolution layer are obtained by the input of the gated activation unit. This patent is aimed at the risk assessment of buried gas pipelines, and does not involve the risk assessment of gas pipelines in the integrated pipeline corridor, and does not consider the characteristics of risk assessment under this specific condition.

[0004] The Chinese patent with the publication number CN118690661A and the application date of August 23, 2024 discloses "Dynamic risk assessment method and equipment for failure of gas pipelines in integrated pipe corridors". According to the accident tree and event tree model of failure of gas pipelines in integrated pipe corridors, a Bow-tie model of failure of gas pipelines in integrated pipe corridors is constructed, and the Bow-tie model of failure of gas pipelines in pipe corridors is converted into a dynamic Bayesian network model to determine the consequences of accidents caused by pipeline failure events. According to the risk calculation model, the consequences of accidents are evaluated to obtain risk assessment results. This method is relatively complex, not universal and general, and has certain difficulties in actual operation and use. Summary of the invention

[0005] The purpose of the present invention is to provide a method for risk assessment of gas pipelines in urban underground comprehensive pipe galleries. The method can be used to reasonably assess the risk level of gas pipelines in urban underground comprehensive pipe galleries.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] A method for risk assessment of gas pipelines in an urban underground integrated pipe gallery of the present invention comprises the following steps:

[0008] Step 1: Determine the possibility of accidents occurring in the city's underground integrated pipe gallery gas pipelines;

[0009] Step 2: Calculate the vulnerability of the gas pipeline in the integrated pipeline gallery;

[0010] Step 3: Determine the severity of the accident consequences of the urban underground integrated pipe gallery gas pipeline by calculating the severity of the accident consequences and the accident prevention capability;

[0011] Step 4: Based on the possibility of accidents in the urban underground integrated pipe gallery gas pipeline, the vulnerability of the integrated pipe gallery gas pipeline and the severity of the accident consequences, the risk score of the urban underground integrated pipe gallery gas pipeline is calculated. The calculation formula is:

[0012]

[0013] Where Rsik is the pipeline risk; P is the possibility of an accident; V is the pipeline vulnerability; I is the severity of the accident consequences;

[0014] Step 5. Determine the risk level of the gas pipelines in the urban underground comprehensive pipeline corridor according to the risk score of the gas pipelines in the urban underground comprehensive pipeline corridor and take corresponding disposal measures.

[0015] The beneficial effects of the present invention are:

[0016] (1) The conventional pipeline risk assessment method is to determine the risk level by the possibility of pipeline accidents and the severity of accident consequences. This method adds pipeline vulnerability indicators, considers the possibility of risks caused by the pipeline's own characteristics, and also considers the pipeline prevention capability indicators in the severity of accident consequences. It also takes into account indicators such as emergency plans, emergency support, and education and training that can reduce the severity of pipeline accident consequences. The established risk assessment indicator system is more systematic, comprehensive, comprehensive, and reasonable.

[0017] (2) This method conducts risk assessment on gas pipelines in integrated pipeline corridors. When considering risk indicators, it highlights the characteristics of integrated pipeline corridors and proposes indicators including the corridor itself, pipelines entering the corridor, and ancillary facilities in the corridor. This method can solve the technical problems of risk assessment of gas pipelines in integrated pipeline corridors.

[0018] (3) The risk assessment calculation method proposed in this method is simple and highly operational, and the risk assessment indicators proposed are highly universal. When using this assessment method, only experts are used to determine the quantitative values ​​of each secondary indicator, that is, the quantitative scores of the secondary indicators are determined according to the actual situation of the assessed pipeline. The risk value and risk level of the assessed pipeline can be obtained through simple calculations. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a flow chart of a method for risk assessment of gas pipelines in an urban underground integrated pipe gallery according to the present invention;

[0020] Figure 2 It is an index of the possibility of gas pipeline accidents occurring in the urban underground integrated pipe gallery of the present invention;

[0021] Figure 3 It is the vulnerability index of the gas pipeline in the urban underground comprehensive pipe gallery of the present invention;

[0022] Figure 4 It is the severity index of the consequences of the gas pipeline accident in the urban underground comprehensive pipe gallery of the present invention;

[0023] Figure 5 It is the gas pipeline accident prevention capability index of the urban underground comprehensive pipeline gallery of the present invention. DETAILED DESCRIPTION

[0024] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments:

[0025] As attached Figure 1 As shown, the present invention provides a method for risk assessment of gas pipelines in an urban underground integrated pipe gallery, comprising the following steps:

[0026] Step 1: Determine the possibility of an accident in the city's underground integrated pipe gallery gas pipeline, which specifically includes the following steps:

[0027] Step 101, determine the probability index of the accident of the gas pipeline in the urban underground integrated pipe gallery, as shown in the attached Figure 2 As shown, there are four factors, including corrosion, design and construction defects, misoperation and environmental factors.

[0028] Step 102, determining the weight of the accident probability index of the integrated pipe gallery gas pipeline, can be done by searching the statistical data of gas pipeline accidents in relevant cities, counting the number of various types of accidents that occurred in the evaluated integrated pipe gallery gas pipeline, the length of the evaluated integrated pipe gallery gas pipeline, and the service life of the evaluated integrated pipe gallery gas pipeline. The various types of accidents refer to accidents caused by corrosion, design and construction defects, misoperation, and environmental factors. The weight formula of the accident probability index of the integrated pipe gallery gas pipeline is:

[0029] (1)

[0030] (2)

[0031] Where e i is the failure rate function of the accident type corresponding to the i-th accident probability index within the statistical period. When i=1, 2, 3, 4, e iThey represent the failure rate functions of accidents caused by corrosion, design and construction defects, misoperation, and environmental factors; m i is the total number of accident types corresponding to the i-th accident probability index within the statistical period. When i=1, 2, 3, 4, m i They represent the total number of accidents caused by corrosion, design and construction defects, misoperation, and environmental factors respectively; L is the length of the gas pipeline in the evaluated integrated pipe gallery; N is the statistical number of years for gas pipeline accidents (the statistical number refers to the number of various accidents that have occurred in the past 10 or 15 years, determined based on statistical data); t is the service life of the gas pipeline in the evaluated integrated pipe gallery; W P i is the weight of the probability index of the ith accident.

[0032] Step 103, classify the accident probability index and calculate the quantitative value. The specific process is as follows:

[0033] The accident probability index is divided into 5 levels, and the quantitative value K p i They are 1, 2, 3, 4, and 5, representing that such accidents are unlikely to occur in urban underground comprehensive pipeline corridor gas pipelines, such accidents occasionally occur, such accidents occur from time to time, such accidents occur regularly, and such accidents occur frequently.

[0034] Step 104, calculate the probability of the accident, the calculation formula is as follows:

[0035] (3)

[0036] Where P is the probability of an accident; n is the number of accident probability indicators; W p i is the weight of the probability index of the i-th accident; K p i is the quantitative value of the factors affecting the possibility of the i-th accident. When i=1, 2, 3, 4, K p i They represent the possibility of accidents in the assessed pipeline due to corrosion, design and construction defects, misoperation, and environmental factors. K is determined based on the actual situation of the assessed pipeline. p i The quantitative value of K p The quantitative values ​​of 1 are 1, 2, 3, 4, and 5, which respectively indicate that accidents due to corrosion are unlikely to occur in the assessed pipeline, accidents due to corrosion may occur occasionally, accidents due to corrosion occur from time to time, accidents due to corrosion occur regularly, and accidents due to corrosion occur frequently.

[0037] Step 2: Calculate the vulnerability of the gas pipeline in the integrated pipe gallery. The specific process is as follows:

[0038] Step 201, determine the vulnerability index of the gas pipeline in the integrated pipe gallery, such as Figure 3 As shown:

[0039] The first-level indicators include the surrounding environment of the pipeline corridor, underground integrated pipeline corridor, gas pipeline system and other factors;

[0040] The second-level indicators include: the pipeline corridor itself, pipelines entering the corridor and ancillary facilities in the corridor included in the pipeline corridor indicators; the geological conditions, seismic intensity, pipeline area grade and surrounding underground space conditions included in the surrounding environment indicators of the underground comprehensive pipeline corridor; the gas pipelines, gas pipeline accessories and gas pipeline protection measures included in the gas pipeline system indicators; the procedural compliance, unit qualifications and operation and maintenance management system of the construction process included in other factor indicators.

[0041] The pipe gallery body refers to the pipe gallery structure, which is a cast-in-place concrete structure, a prefabricated assembled concrete structure, a steel structure or other structures;

[0042] The pipelines entering the corridor refer to whether there are other pipelines in the integrated pipeline corridor besides the gas pipeline, including water supply and renewable water pipelines, drainage pipelines, thermal pipelines, power cables, communication cables and other pipelines;

[0043] The ancillary facilities in the corridor refer to whether there are flammable gas detection and alarm systems, fire protection systems, ventilation systems, monitoring and alarm systems, drainage systems, power supply and lighting systems, sign systems, etc. in the integrated pipe corridor;

[0044] The surrounding underground space conditions refer to whether there are underground traffic conditions, underground commercial projects, underground civil air defense projects and other underground projects within 200 meters on both sides of the gas pipeline in the integrated pipe gallery;

[0045] The gas pipeline refers to the pipeline operating pressure and pipe material conditions;

[0046] The gas pipeline accessories refer to whether the settings of sectional valves, pipeline relief measures, pipeline compensation measures, etc. are reasonable;

[0047] The pipeline protection measures refer to whether the anti-corrosion layer, lightning protection and anti-static grounding measures, earthquake-resistant measures, and anti-floating measures are reasonably set.

[0048] Step 202, determine the weight of the vulnerability index of the gas pipeline in the integrated pipe gallery, and use the hierarchical analysis method to determine the respective weights of the first-level index and the second-level index in the vulnerability index through expert scoring:

[0049] The specific steps of the present invention are described below by taking examples:

[0050] Step 221, using expert questionnaire survey judgment analysis, divide the importance of the first-level indicators into 9 levels, and compare them pairwise. According to the importance of the two-way comparison of indicators, a vulnerability indicator judgment matrix is ​​constructed, where 1, 3, 5, 7, and 9 respectively represent that two indicators are equally important, slightly important, quite important, obviously important, and absolutely important, and 2, 4, 6, and 8 are between two important indicators; relatively unimportant indicators are taken in the form of reciprocal values, such as 1 / 3, 1 / 5, 1 / 7, 1 / 9, etc. The same method is used to construct the judgment matrix of the second-level indicators;

[0051] Judgment matrix:

[0052] (4)

[0053] Where A ij is the element of the judgment matrix A, which represents the scale of the relative importance of index i and index j; n is the order of the judgment matrix A, that is, the number of first-level indexes or second-level indexes;

[0054] Step 2022, perform normalization processing, calculate the product of each row of the judgment matrix, and then perform nth root calculation on the product to complete the normalization processing of the data and obtain the indicator weight.

[0055] (5)

[0056] (6)

[0057] (7)

[0058] Where M i is the product of the elements in the i-th row of the judgment matrix A; n is the order of the judgment matrix A, that is, the number of first-level indicators or second-level indicators; A ij is the element of the judgment matrix A; m i is the nth root of the product of the elements in the i-th row of the judgment matrix A (the value of the nth root is equal to the order of the judgment matrix. When calculating the weight of the first-level indicators, n is the number of the first-level indicators. When calculating the weight of the second-level indicators, n is the number of the second-level indicators). W i is the weight of the i-th indicator;

[0059] Step 2023, calculate the maximum eigenvalue λ of the judgment matrix max , calculate the consistency ratio C R , C R When it is less than 0.1, the consistency test is satisfied. The specific formula is as follows:

[0060] (8)

[0061] (9)

[0062] (10)

[0063] (11)

[0064] Where R is the newly constructed matrix (n×1); A is the judgment matrix; W is the weight matrix of the indicator (n×1); λ max is the maximum eigenvalue; R i is the i-th element of the newly constructed matrix R; Wi is the weight of the i-th indicator; C I is the consistency index; C R is the consistency ratio; R I is a random consistency index. When n is 1, 2, 3, 4, 5, 6, 7, 8, 9, R I They are 0, 0, 0.58, 0.90, 1.12, 1.24, 1.32, 1.41 and 1.45 respectively.

[0065] Step 203: classify and quantify the second-level indicators of pipeline vulnerability. The specific process is as follows: the second-level indicators in the pipeline vulnerability index are divided into 5 levels, and the quantization value K V ij They are 1, 2, 3, 4, and 5, representing the extremely low vulnerability, low vulnerability, medium vulnerability, high vulnerability, and extremely high vulnerability of the urban underground comprehensive pipeline gallery gas pipelines.

[0066] Step 204, calculate the pipeline vulnerability, the formula is as follows:

[0067] (12)

[0068] Where V is the pipeline vulnerability; n V is the number of first-level vulnerability indicators; m V is the number of second-level vulnerability indicators under the i-th first-level indicator; W V i is the weight of the i-th first-level vulnerability indicator; W V ij K is the weight of the jth second-level vulnerability indicator under the i-th first-level indicator; V ij is the quantitative value of the jth second-level vulnerability indicator under the i-th first-level indicator. K is determined according to the actual situation of the pipeline being evaluated. V ij The quantitative value of K V 11 The quantitative values ​​of are 1, 2, 3, 4, and 5, which respectively indicate that the corridor itself in the corridor causes extremely low vulnerability, low vulnerability, medium vulnerability, high vulnerability, and extremely high vulnerability of the gas pipeline.

[0069] Step 3: Determine the severity of accident consequences of urban underground integrated pipe gallery gas pipelines through calculation of accident consequence severity and accident prevention capability. The calculation method is as follows:

[0070] Step 301, determine the severity index of the accident consequence of the urban underground integrated pipe gallery gas pipeline, as shown in the attached Figure 4 As shown, it includes the first-level accident consequence severity index and the second-level accident consequence severity index; the first-level accident consequence severity indexes are respectively personal injury, economic loss and social impact;

[0071] The second-level accident consequence severity indicators include: population density along the line included in the personal injury index; building types, building density along the line and user gas interruption included in the economic loss index; city influence, importance of surrounding units, gas outage impact range and traffic impact included in the social impact index.

[0072] Determine the indicators for judging accident prevention capabilities, such as Figure 5 As shown, it includes first-level accident prevention capability indicators and second-level accident prevention capability indicators. The first-level accident prevention capability indicators include emergency plans, emergency support and education and training; the second-level accident prevention capability indicators include: plan formulation and plan management included in the emergency plan indicators; emergency communications and material equipment included in the emergency support indicators; publicity and education, emergency training and emergency drills included in the education and training indicators.

[0073] Step 302, determine the weight of the accident consequence severity index and the weight of the accident prevention capability index. Similarly, the analytic hierarchy process can be used to determine the index weights through expert scoring. The calculation formula is shown in formulas (4) to (11).

[0074] Step 303: classify and quantify the second-level indicators of the severity of the accident consequences into 5 levels, with the quantification value K C ij They are 1, 2, 3, 4, and 5, representing the consequences of gas pipeline accidents in urban underground comprehensive pipeline corridors as not serious, serious, relatively serious, very serious, and very serious.

[0075] The second-level indicators of prevention capability are graded and quantified into 5 levels, with a quantified value of K. F ij They are 1, 2, 3, 4, and 5, representing strong, relatively strong, average, relatively weak, and weak capabilities in preventing accidents of gas pipelines in urban underground comprehensive pipeline corridors.

[0076] Step 304, calculate the severity of the accident consequences, the formula is as follows:

[0077] (13)

[0078] Where C is the severity of the accident consequences; n C is the number of first-level accident consequence severity indicators; m C is the number of second-level accident consequence severity indicators under the i-th first-level indicator; W C i is the weight of the severity index of the i-th first-level accident consequence; W C ij K is the weight of the jth second-level accident consequence severity indicator under the i-th first-level indicator; C ij K is the quantitative value of the jth second-level accident consequence severity index under the i-th first-level index. K is determined according to the actual situation of the pipeline being evaluated. C ij The quantitative value of K C 11 When the quantitative value of is 1, 2, 3, 4, and 5, it means that the accident consequences caused by the population density along the line in personal injury are not serious, serious, relatively serious, very serious, and very serious, respectively.

[0079] The accident prevention capability is calculated using the following formula:

[0080] (14)

[0081] (15)

[0082] Where F is the accident prevention capability; n F is the number of first-level accident prevention capability indicators; m F is the number of second-level accident prevention capability indicators under the i-th first-level indicator; W F i is the weight of the i-th first-level accident prevention capability indicator; W F ij K is the weight of the jth second-level accident prevention capability indicator under the i-th first-level indicator; F ij is the quantitative value of the jth second-level accident prevention capability indicator under the i-th first-level indicator. K is determined according to the actual situation of the pipeline being evaluated. F ij The quantitative value of K F 11 The quantitative value of is 1, 2, 3, 4, and 5, which respectively represent the pipeline accident prevention capability brought about by the emergency plan formulation as strong, relatively strong, average, relatively weak, and weak; f is the accident prevention capability coefficient.

[0083] Step 305, calculate the severity of the consequences of the gas pipeline accident in the urban underground integrated pipe gallery, the formula is as follows:

[0084] (16)

[0085] Where I is the severity of the accident consequences; C is the severity of the accident consequences; and f is the accident prevention capability coefficient.

[0086] Step 4: Based on the possibility of accidents in the urban underground comprehensive pipe gallery gas pipeline, pipeline vulnerability and the severity of accident consequences, calculate the risk score of the urban underground comprehensive pipe gallery gas pipeline. The calculation formula is:

[0087] (17)

[0088] Where Rsik is the pipeline risk; P is the possibility of an accident; V is the pipeline vulnerability; and I is the severity of the accident consequences.

[0089] Step 5. According to the risk score of the gas pipeline in the urban underground comprehensive pipeline gallery, determine the risk level of the gas pipeline in the urban underground comprehensive pipeline gallery and take corresponding disposal methods. The disposal methods can be: when the risk score is between 0 and 4, the risk level is extremely low risk, and extremely low risk is an acceptable risk. The risk level is maintained according to the risk disposal plan; when the risk score is between 5 and 9, the risk level is low risk, and response measures should be taken for low risk, and disposal plans should be formulated in time; when the risk score is between 10 and 16, the risk level is medium risk, and emergency response measures should be taken for medium risk to reduce the risk as soon as possible; when the risk score is between 17 and 25, the risk level is high risk, and disposal measures should be taken immediately for high risk, and the pipeline operation should be stopped before the risk is reduced.

[0090] The technical solution of the present invention is described below with a specific embodiment:

[0091] A risk assessment was conducted on a city's underground integrated pipe gallery gas pipeline project, which is located near a shopping mall in a megacity. The pipe gallery is a prefabricated assembled concrete structure trunk integrated pipe gallery with complete ancillary facilities and pipelines, including water supply and recycled water pipelines, drainage pipelines, thermal pipelines, power cables and communication cables. The gas pipeline is a DN600 sub-high pressure pipeline made of low alloy steel, with a length of 100m and normal operation of 5 years. The conditions that affect the risk level of pipelines include the following: (1) Pipeline corridors: The overall planning and design of the pipeline corridors are good, the natural gas pipelines and water supply pipelines are in the same cabin, the locations of some nodes such as the personnel entrances and exits are unreasonable, and some ancillary facilities such as the combustible gas detection alarm system, fire protection system, ventilation system, and sign system in the corridor need to be improved and improved. Other contents are in compliance with relevant technical standards; (2) Surrounding environment: The geological conditions where the pipeline corridor project is located are basically good, the site is basically stable, the geotechnical engineering properties are Class II, the groundwater level is lower than the bottom of the pipeline corridor, there is no liquefaction of the foundation, the earthquake intensity is 6 degrees, the pipeline area level is Class II, and there are underground transportation and underground commercial projects near the pipeline corridor; (3) Gas pipeline system: The pipeline release measures need to be improved and improved, the pipeline lacks lightning protection and anti-static grounding measures, and no anti-floating verification has been performed. Other contents are in compliance with relevant technical standards; (4) Other factors: The planning, feasibility study preparation units and construction units lack relevant performance.

[0092] Step 1: Calculate the probability of gas pipeline accidents in urban underground integrated pipe corridors, as follows:

[0093] Step 101 Determine the probability indicators of gas pipeline accidents in urban underground integrated pipe corridors, including corrosion, design and construction defects, misoperation, and environmental factors.

[0094] Step 102: Determine the weight of the accident probability index. Take the statistical data of different causes of gas transmission and distribution pipeline accidents in the United States from 2010 to 2023 as an example for analysis. The accidents caused by corrosion, design and construction defects, misoperation, and environmental factors in gas transmission and distribution pipelines are 33, 155, 105, and 1026 respectively. The pipeline length is 100 m. The statistical pipeline accident period is 13 years, and the pipeline service life is 5 years. According to formulas (1) to (2), the weights of corrosion, design and construction defects, misoperation, and environmental factors are 0.0144, 0.0708, 0.0469, and 0.8679 respectively.

[0095] Step 103: Determine the accident probability index level description and its quantitative value. According to the actual operation of the urban underground integrated pipe gallery gas pipeline, the quantitative values ​​of the accident probability caused by corrosion, design and construction defects, misoperation, and environmental factors are determined to be 3, 3, 2, and 1 respectively.

[0096] Step 104: Based on the weight and quantified value of the accident probability index, formula (3) is used to calculate the probability of a gas pipeline accident in the urban underground integrated pipe gallery to be 1.2173.

[0097] Step 2: Calculate the vulnerability of the gas pipeline in the urban underground integrated pipeline gallery, as follows:

[0098] Step 201 Determine the vulnerability indicators of the gas pipelines in the urban underground comprehensive pipeline corridor, including the first-level indicators and the second-level indicators. The first-level indicators include 4 factors: the pipeline corridor, the surrounding environment, the gas pipeline system, and other factors. The second-level indicators include 13 factors: the pipeline corridor itself, the pipelines entering the corridor, the ancillary facilities in the corridor, the geological conditions, the earthquake intensity, the pipeline area grade, the surrounding underground space conditions, the gas pipelines, the gas pipeline accessories, the gas pipeline protection measures, the procedural compliance of the construction process, the unit qualifications, and the operation and maintenance management system.

[0099] Step 202: Determine the weight of the pipeline vulnerability index. The index weight is determined by expert scoring using the hierarchical analysis method. The calculation results are as follows:

[0100] Table 1 Judgment matrix of the first-level vulnerability indicators

[0101]

[0102] Maximum eigenvalue λ max =4.1391, CI=0.0464, CR=CI / RI=0.0515<0.1, which satisfies the consistency check.

[0103] Table 2 Judgment matrix of the second level indicators under the first level vulnerability indicator corridor

[0104]

[0105] Maximum eigenvalue λ max =3, CI=0, CR=CI / RI=0<0.1, which satisfies the consistency check.

[0106] Table 3 Judgment matrix of second-level indicators in the surrounding environment of first-level vulnerability indicators

[0107]

[0108] Maximum eigenvalue λ max =4, CI=0, CR=CI / RI=0<0.1, which satisfies the consistency check.

[0109] Table 4 Judgment matrix of second-level indicators under the first-level vulnerability indicator gas pipeline system

[0110]

[0111] Maximum eigenvalue λ max =3, CI=0, CR=CI / RI=0<0.1, which satisfies the consistency check.

[0112] Table 5 Judgment matrix of the second-level indicators under other factors of the first-level vulnerability indicators

[0113]

[0114] Maximum eigenvalue λ max =3, CI=0, CR=CI / RI=0<0.1, which satisfies the consistency check.

[0115] Step 203: Determine the second-level index quantitative value of pipeline vulnerability according to the basic situation of the assessed pipeline corridor, which are as follows:

[0116] Table 6 Pipeline vulnerability second-level indicator weights and their quantitative values

[0117]

[0118] Step 204: According to the pipeline vulnerability index weight and quantitative value, based on formula (12), the pipeline vulnerability score is calculated to be 2.6441.

[0119] Step 3: Calculate the severity of the consequences of the gas pipeline accident in the urban underground integrated pipe gallery, as follows:

[0120] Step 301 Determine the severity index of the consequences of gas pipeline accidents in urban underground comprehensive pipe corridors, including first-level indicators and second-level indicators. The first-level indicators include 3: personal injury, economic loss, and social impact. The second-level indicators include 8: population density along the line, building type, building density along the line, user interruption, urban influence, importance of surrounding units, gas outage impact range, and traffic impact. At the same time, determine the urban underground comprehensive pipe corridor gas accident prevention capability index, including second-level indicators. The first-level indicators include 3: emergency plan, emergency support, and education and training. The second-level indicators include 7: plan formulation, plan management, emergency communication, materials and equipment, publicity and education, emergency training, and emergency drills.

[0121] Step 302: Determine the weight of the accident consequence severity index and the accident prevention capability index. The analytic hierarchy process is also used to determine the index weight through expert scoring. The calculation results are as follows according to formulas (4) to (11):

[0122] Table 7 Judgment matrix of the first level accident consequence severity index

[0123]

[0124] Maximum eigenvalue λ max=3, CI=0, CR=CI / RI=0<0.1, which satisfies the consistency check.

[0125] Table 8 Judgment matrix of second-level indicators under the first-level accident consequence severity index economic loss

[0126]

[0127] Maximum eigenvalue λ max =3, CI=0, CR=CI / RI=0<0.1, which satisfies the consistency check.

[0128] Table 9 Judgment matrix of the second level indicators under the social impact of the first level accident consequence severity indicators

[0129]

[0130] Maximum eigenvalue λ max =4.0434, CI=0.0145, CR=CI / RI=0.0161<0.1, which satisfies the consistency check.

[0131] Table 10 Judgment matrix of first-level accident prevention capability indicators

[0132]

[0133] Maximum eigenvalue λ max =3, CI=0, CR=CI / RI=0<0.1, which satisfies the consistency check.

[0134] Table 11 Judgment matrix of second-level indicators under the first-level accident prevention capability indicator emergency plan

[0135]

[0136] Maximum eigenvalue λ max =, CI=, CR=CI / RI=<0.1, which satisfies the consistency check.

[0137] Table 12 Second-level indicator judgment matrix under the first-level accident prevention capability indicator emergency guarantee

[0138]

[0139] Maximum eigenvalue λ max =, CI=, CR=CI / RI=<0.1, which satisfies the consistency check.

[0140] Table 13 Judgment matrix of second-level indicators under first-level accident prevention capability indicator education and training

[0141]

[0142] Maximum eigenvalue λ max =3, CI=0, CR=CI / RI=0<0.1, which satisfies the consistency check.

[0143] Step 303: Determine the second-level indicator quantification value of the severity of accident consequences and the second-level indicator quantification value of the accident prevention capability according to the basic situation of the evaluated pipeline corridor, and the results are as follows:

[0144] Table 14 Accident consequence severity index weights and their quantitative values

[0145]

[0146] Table 15 Accident prevention capability index weights and their quantitative values

[0147]

[0148] Step 304: According to the weights and quantitative values ​​of the accident consequence severity and accident prevention capability indicators, based on formulas (13) and (14), the accident consequence severity and accident prevention capability scores are calculated to be 2.8372 and 1.9081 respectively. At the same time, based on formula (15), the accident prevention capability coefficient is determined to be 0.85.

[0149] Step 305 Based on the accident consequence severity score and the accident prevention capability coefficient, and based on formula (16), the accident consequence severity score of the urban underground integrated pipe gallery gas pipeline is calculated to be 2.4116.

[0150] Step 4: Based on the above-calculated probability score of the gas pipeline accident in the urban underground comprehensive pipeline corridor, the pipeline vulnerability score and the severity score of the accident consequences, the urban underground comprehensive pipeline corridor gas pipeline risk score is calculated to be 6.3765 based on formula (17).

[0151] Step 5: According to the risk score of the gas pipeline in the urban underground comprehensive pipeline corridor, it is 6.3765. When it is 5 to 9, the risk level is low risk. Countermeasures should be taken for low risk and disposal plans should be formulated in time.

Claims

1. A method for risk assessment of gas pipelines in urban underground integrated pipe gallery, characterized in that The steps include: Step 1: Determine the possibility of accidents occurring in the city's underground integrated pipe gallery gas pipelines; Step 2: Calculate the vulnerability of the gas pipeline in the integrated pipeline gallery; Step 3: Determine the severity of the accident consequences of the urban underground integrated pipe gallery gas pipeline by calculating the severity of the accident consequences and the accident prevention capability; Step 4: Based on the possibility of accidents in the urban underground integrated pipe gallery gas pipeline, the vulnerability of the integrated pipe gallery gas pipeline and the severity of the accident consequences, the risk score of the urban underground integrated pipe gallery gas pipeline is calculated. The calculation formula is: Where Rsik is the pipeline risk; P is the possibility of an accident; V is the pipeline vulnerability; I is the severity of the accident consequences; Step 5. Determine the risk level of the gas pipelines in the urban underground comprehensive pipeline corridor according to the risk score of the gas pipelines in the urban underground comprehensive pipeline corridor and take corresponding disposal measures.

2. The urban underground comprehensive pipe gallery gas pipeline risk assessment method according to claim 1 is characterized in that: The step 1 specifically includes the following steps: Step 101, determining the accident possibility index of the gas pipeline in the urban underground integrated pipe gallery, including corrosion, design and construction defects, misoperation and environmental factors; Step 102, determine the weight of the accident probability index of the integrated pipe gallery gas pipeline, count the number of various types of accidents that occurred in the evaluated integrated pipe gallery gas pipeline, the length of the evaluated integrated pipe gallery gas pipeline and the service life data of the evaluated integrated pipe gallery gas pipeline, the various types of accidents refer to accidents caused by corrosion, design and construction defects, misoperation, and environmental factors. The weight formula of the accident probability index of the integrated pipe gallery gas pipeline is: Where e i is the failure rate function of the accident type corresponding to the i-th accident probability index within the statistical period. When i=1, 2, 3, 4, e i They represent the failure rate functions of accidents caused by corrosion, design and construction defects, misoperation, and environmental factors; m i is the total number of accident types corresponding to the i-th accident probability index within the statistical period. When i=1, 2, 3, 4, m i They represent the total number of accidents caused by corrosion, design and construction defects, misoperation, and environmental factors respectively; L is the length of the gas pipeline in the evaluated integrated pipeline corridor; N is the statistical number of years in which accidents occurred in the gas pipeline; t is the service life of the gas pipeline in the evaluated integrated pipeline corridor; W P i is the weight of the probability index of the i-th accident; Step 103, classify the accident probability index and calculate the quantitative value. The specific process is as follows: The accident probability index is divided into 5 levels, and the quantitative value K p i They are 1, 2, 3, 4, and 5, representing that such accidents are unlikely to occur in the urban underground comprehensive pipe gallery gas pipeline, such accidents occur occasionally, such accidents occur from time to time, such accidents occur regularly, and such accidents occur frequently; Step 104, calculate the probability of the accident, the calculation formula is as follows: Where P is the probability of an accident; n is the number of accident probability indicators; W p i is the weight of the probability index of the i-th accident; K p i is the quantitative value of the factors affecting the possibility of the i-th accident. When i=1, 2, 3, 4, K p i They respectively represent the possibility of accidents occurring in the assessed pipeline due to corrosion, design and construction defects, misoperation, and environmental factors.

3. The urban underground integrated pipe gallery gas pipeline risk assessment method according to claim 1 or 2, characterized in that: The specific process of step 2 is as follows: Step 201, determine the vulnerability index of the gas pipeline in the integrated pipe gallery: The first-level indicators include the surrounding environment of the pipeline corridor, underground integrated pipeline corridor, gas pipeline system and other factors; The second level indicators include: the pipeline corridor itself, pipelines entering the corridor and ancillary facilities in the corridor included in the pipeline corridor indicators; The surrounding environment indicators of underground integrated pipeline corridors include geological conditions, earthquake intensity, pipeline area grade and surrounding underground space conditions; the indicators of gas pipeline systems include gas pipelines, gas pipeline accessories and gas pipeline protection measures; the procedural compliance, unit qualifications and operation and maintenance management system of the construction process include other factor indicators; Step 202, determine the weight of the vulnerability index of the gas pipeline in the integrated pipe gallery, and use the hierarchical analysis method to determine the respective weights of the first-level index and the second-level index in the vulnerability index through expert scoring: Step 203, classify and quantify the second-level indicators of pipeline vulnerability. The specific process is as follows: the second-level indicators in the pipeline vulnerability index are divided into 5 levels, and the quantization value K V ij They are 1, 2, 3, 4, and 5, respectively representing the extremely low vulnerability, low vulnerability, medium vulnerability, high vulnerability, and extremely high vulnerability of the urban underground integrated pipeline gallery gas pipeline; Step 204, calculate the pipeline vulnerability, the formula is as follows: Where V is the pipeline vulnerability; n V is the number of first-level vulnerability indicators; m V is the number of second-level vulnerability indicators under the i-th first-level indicator; W V i is the weight of the i-th first-level vulnerability indicator; W V ij K is the weight of the jth second-level vulnerability indicator under the i-th first-level indicator; V ij It is the quantitative value of the jth second-level vulnerability indicator under the i-th first-level indicator.

4. The method for risk assessment of urban underground integrated pipe gallery gas pipelines according to claim 3 is characterized by: The calculation method in step 3 is as follows: Step 301, determining and judging the accident consequence severity index of the urban underground integrated pipe gallery gas pipeline, including the first-level accident consequence severity index and the second-level accident consequence severity index; the first-level accident consequence severity index is respectively personal injury, economic loss and social impact; The second-level accident consequence severity indicators include: population density along the line included in the personal injury index; building types, building density along the line and user interruption of gas use included in the economic loss index; city influence, importance of surrounding units, gas outage impact range and traffic impact included in the social impact index; Determine the indicators for judging accident prevention capabilities, including first-level accident prevention capability indicators and second-level accident prevention capability indicators. The first-level accident prevention capability indicators include emergency plans, emergency support, and education and training; the second-level accident prevention capability indicators include: plan formulation and plan management included in the emergency plan indicators; emergency communications and supplies and equipment included in the emergency support indicators; publicity and education, emergency training, and emergency drills included in the education and training indicators; Step 302, using the analytic hierarchy process to determine the weight of the accident consequence severity index and the weight of the accident prevention capability index through expert scoring; Step 303: classify and quantify the second-level indicators of the severity of the accident consequences into 5 levels, with the quantification value K C ij They are 1, 2, 3, 4, and 5, representing the consequences of gas pipeline accidents in urban underground comprehensive pipe corridors are not serious, serious, relatively serious, very serious, and very serious respectively; The second-level indicators of prevention capability are graded and quantified into 5 levels, with a quantified value of K. F ij They are 1, 2, 3, 4, and 5, representing strong, relatively strong, average, relatively weak, and weak capabilities in preventing accidents of gas pipelines in urban underground comprehensive pipe galleries; Step 304, calculate the severity of the accident consequences, the formula is as follows: Where C is the severity of the accident consequences; n C is the number of first-level accident consequence severity indicators; m C is the number of second-level accident consequence severity indicators under the i-th first-level indicator; W C i is the weight of the severity index of the i-th first-level accident consequence; W C ij K is the weight of the jth second-level accident consequence severity indicator under the i-th first-level indicator; C ij is the quantitative value of the jth second-level accident consequence severity indicator under the i-th first-level indicator; The accident prevention capability is calculated using the following formula: Where F is the accident prevention capability; n F is the number of first-level accident prevention capability indicators; m F is the number of second-level accident prevention capability indicators under the i-th first-level indicator; W F i is the weight of the i-th first-level accident prevention capability indicator; W F ij K is the weight of the jth second-level accident prevention capability indicator under the i-th first-level indicator; F ij is the quantitative value of the jth second-level accident prevention capability indicator under the i-th first-level indicator; f is the accident prevention capability coefficient; Step 305, calculate the severity of the consequences of the gas pipeline accident in the urban underground integrated pipe gallery, the formula is as follows: Where I is the severity of the accident consequences; C is the severity of the accident consequences.

5. The method for risk assessment of urban underground integrated pipe gallery gas pipelines according to claim 1 or 2, characterized in that: The step five includes the following steps: when the risk score is between 0 and 4, the risk level is extremely low risk, which is an acceptable risk, and the risk level is maintained according to the risk disposal plan; when the risk score is between 5 and 9, the risk level is low risk, and response measures should be taken for low risk, and disposal plans should be formulated in time; when the risk score is between 10 and 16, the risk level is medium risk, and emergency response measures should be taken for medium risk to reduce the risk as soon as possible; when the risk score is between 17 and 25, the risk level is high risk, and disposal measures should be taken immediately for high risk, and pipeline operation should be stopped before the risk is reduced.

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