Numerical simulation method for predicting vibration velocity of PE gas pipeline under blasting load

Abstract

The application discloses a numerical simulation method for predicting vibration speed of PE gas pipeline under blasting load. The method uses three-dimensional simulation software to establish a PE pipeline blasting model, and then obtains the dynamic parameters of the material in the PE pipeline blasting model; a model boundary condition and a related algorithm keyword are added to the PE pipeline blasting model; according to the investigation specification and the subway construction data, a plurality of PE pipeline blasting sub-models are established based on the PE pipeline blasting model in step S1 by using the orthogonal experiment theory; a plurality of experimental data are obtained; finally, the plurality of experimental data are fitted by using the dimensional analysis method, and a vibration speed prediction formula of the buried polyethylene gas pipeline under the blasting load is obtained. The method solves the problem that it is difficult to predict the vibration speed of the buried polyethylene gas pipeline under the blasting load in the actual engineering process, and the numerical simulation method is used to establish the pipeline numerical model step by step, and the method is simple and easy to implement.

Description

Technical Field

[0001] This invention relates to the fields of pipeline engineering and blasting engineering technology, specifically to a numerical simulation method for predicting the vibration velocity of polyethylene gas pipelines under blasting loads. Background Technology

[0002] Polyethylene is widely used in urban gas pipeline systems due to its excellent impact resistance, corrosion resistance, and ease of installation. The damage caused by a gas pipeline rupture under external load is immense. Gas pipelines are generally laid along main urban roads, and the types of external loads they experience include vehicle live loads, ground deformation, and vibration loads, with vibration loads having the greatest impact. Vibration loads are mainly generated by natural earthquakes and earthquakes caused by human activities. The complex geological conditions in cities, with soil overlying rock, make subway tunnel construction difficult. When encountering hard rock during excavation, blasting is often used to break the rock, but this leads to secondary disasters, such as blast earthquakes, which are a major source of man-made earthquakes.

[0003] Predicting the vibration velocity of polyethylene gas pipelines under blasting excavation loads and adjusting appropriate blasting parameters for safe construction are pressing issues in blasting operations. The rapid development of numerical simulation software has facilitated the simulation of the entire blasting process, studying the response of explosive initiation stress waves as they propagate to the structure. This has promoted further research on pipeline response under blasting vibration loads and provided a basis for improving blasting design technology. However, current research on predicting the vibration velocity of polyethylene gas pipelines under blasting loads lacks a unified approach. Limited by the diverse pipeline structures, complex geological conditions, and varying vibration load magnitudes, it is difficult to provide a scientifically sound basis for blasting engineering construction and pipeline safety protection.

[0004] The research findings have significant practical implications and engineering application value for solving safety protection issues in buried pipeline projects and guiding normal construction of blasting projects; they also have important practical significance for enriching methods for predicting pipeline vibration velocity variations, studying pipeline dynamic response, and evaluating safety. Summary of the Invention

[0005] This invention provides a numerical simulation method for predicting the vibration velocity of PE gas pipelines under blasting loads, addressing the problem in existing technologies where it is difficult to effectively predict the vibration velocity of PE gas pipelines under blasting loads. This aims to provide a valid reference for blasting engineering construction and a scientifically sound basis for the protection of buried PE gas pipelines. The method specifically includes the following steps:

[0006] S1: Use 3D simulation software to establish a PE pipeline blasting model and mesh the PE pipeline blasting model; the PE pipeline blasting model includes a rock layer, soil on the rock layer, PE pipeline in the soil, and vertically arranged blast holes spaced apart from the PE pipeline, and explosives at the bottom of the blast.

[0007] S2: Obtain the dynamic parameters of the materials in the PE pipeline blasting model based on the exploration and design data and indoor geotechnical dynamics tests;

[0008] S3: Add model boundary conditions and related algorithm keywords to the PE pipeline blasting model. The related algorithm keywords include the automatic contact keyword between the pipeline and the soil layer, the explosive ALE algorithm keyword, and the keyword for defining and applying the internal pressure load curve of the pipeline.

[0009] S4: Based on the survey specifications and subway construction data, and using the PE pipeline blasting model in step S1, multiple PE pipeline blasting sub-models were established using orthogonal experimental theory. The PE pipeline blasting sub-models included multiple PE gas pipelines of different sizes, the maximum single-segment charge in subway tunnel blasting construction, and the relationship between the pipeline and the seismic source. Simulated blasting experiments were conducted using the above PE pipeline blasting sub-models to obtain multiple sets of experimental data.

[0010] S5: Using dimensional analysis, a mathematical prediction model for pipeline vibration velocity is established. The mathematical prediction model for pipeline vibration velocity is then used to fit multiple sets of experimental data from step S4 to obtain a prediction formula for the vibration velocity of buried polyethylene gas pipelines under blasting load, taking into account pipeline structure, blast center distance, explosive quantity, and pipeline burial depth.

[0011] Furthermore, the process of establishing a PE pipeline burst model using three-dimensional simulation software in step S1 is as follows:

[0012] S101: Combining the unique geological conditions of the urban area, and based on the exploration and design data, investigate the characteristics and thickness of the soil and rock layers in the urban area, and establish a rectangular three-dimensional digital model at a 1:1 scale.

[0013] S102: Based on the typical engineering subway tunnel section blasting construction data, the maximum single-section charge of the section blasting and the shortest distance to the buried PE gas pipeline are obtained, and the blast hole and explosive model are established on the three-dimensional digital model.

[0014] Furthermore, the mesh size of the PE pipe burst model after mesh generation is 5cm.

[0015] Furthermore, in step S2, the selected material model includes

[0016] Rock and explosive plugging material models, soil material models, explosive models, and pipe material models;

[0017] The rock and explosive plugging material models are as follows:

[0018]

[0019] Where: σ y Let σ0 be the yield stress, σ0 be the initial yield stress, C and P be the strain rate parameters, and ε be the strain rate. For effective plastic strain, β is the hardening coefficient, and E P The calculation equation for the plastic hardening modulus is as follows.

[0020]

[0021] Where: E tan E is the tangent modulus, and E is Young's modulus;

[0022] The soil material model is as follows:

[0023]

[0024] Where: T is the shear strength, σ m φ is the average stress, φ is the internal friction angle, and c' is the cohesive force.

[0025] The explosive model is a rock emulsion explosive model, and the JWL equation of state for this rock emulsion explosive model is:

[0026]

[0027] Where: P is the relative specific volume of the detonation products, V is the pressure of the detonation products, E0 is the internal energy per unit volume, and R1, R2, A, B, and ω are material constants.

[0028] Furthermore, in step S3, the methods for adding relevant keywords include:

[0029] S301: To eliminate the reflection effect of the blasting stress wave generated by the explosive blasting at the model boundary, all boundary conditions except the upper surface of the model are set to non-reflection boundary conditions.

[0030] S302: To fully reflect the interaction between the pipeline and the soil layer, automatic surface-to-surface contact is simulated by setting up an automatic surface-to-surface contact mechanism.

[0031] S303: Locate the standard, determine the peak pressure load inside the pipeline, define the load curve, then select the pipeline unit and apply the curve vertically to the inner wall of the pipeline.

[0032] S304: Select the keyword to add control ALE algorithm to simulate the explosion and detonation process.

[0033] Furthermore, in step S4, the methods for determining the numerical model for different working conditions include:

[0034] S401: Based on the Urban Gas Design Code and the Technical Specification for Polyethylene Gas Pipeline Engineering, determine the parameters of five diameters Dn, five wall thicknesses δ, and five internal pressures P for a PE100 pipeline; then, through research on construction data, determine the five maximum single-section charge Q, the five spatial distances R between the seismic source and the pipeline, and the five pipeline burial depths B for tunnel and subway construction.

[0035] S402: Based on the orthogonal experimental theory, some representative points were selected from the comprehensive test for testing. Based on this, 25 sets of orthogonal working conditions with six factors and five levels were comprehensively considered, including pipe diameter Dn, wall thickness δ, maximum single-section charge Q, detonation distance R, burial depth B, and internal pressure P of the pipeline. Numerical models of the relevant working conditions were established according to the working condition sequence number.

[0036] Furthermore, in step S5, the research method for predicting the vibration velocity of PE gas pipelines under blast load includes:

[0037] S501: Considering the relationship between pipeline vibration attenuation and various factors, using the dimensionless analysis method, it is assumed that the pipeline vibration velocity and various influencing factors have the following physical relationship:

[0038] V p =Φ(Q,R,D,δ,B,P,ρ,c)

[0039] Where Vp is the particle velocity in the pipe, Q is the maximum single-stage charge, R is the blasting distance, D is the pipe diameter, δ is the pipe wall thickness, B is the pipe burial depth, P is the internal pressure of the pipe, ρ is the pipe density, and c is the wave velocity in the medium.

[0040] According to the homogeneity theorem of dimensions, if we choose Q, R, and c as dimensionless quantities and the other parameters as dimensionless quantities, we can obtain the dimensionless numbers as follows:

[0041]

[0042] Among them, π, π2, π3, π4, π5, and π6 are all dimensionless parameters;

[0043] Based on practical engineering considerations, when site conditions are constant, density and propagation speed can be approximated as constants.

[0044]

[0045] The above formula can then be expressed as:

[0046]

[0047] Where β, β2, β3, β4, β5, and β6 are all fitting coefficients;

[0048] S502: Statistically analyze the calculation results of various numerical models established in S402, fit the maximum vibration velocity of the pipeline model using the prediction formula, and obtain the vibration velocity prediction formula for buried polyethylene gas pipelines.

[0049] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0050] (1) This invention provides a numerical simulation method for predicting the vibration velocity of PE gas pipelines under blasting loads. A 3D simulation software is used to establish a PE pipeline blasting model. Based on this model, multiple PE pipeline blasting sub-models are established using orthogonal experimental theory to obtain multiple sets of experimental data. Finally, a dimensional analysis method is used to establish a mathematical prediction model for pipeline vibration velocity. This model, combined with multiple sets of experimental data, yields a prediction formula for the vibration velocity of buried polyethylene gas pipelines under blasting loads at different burial depths. This method addresses the lack of a unified approach to predicting the vibration velocity of PE gas pipelines under blasting loads in existing technologies. It fails to comprehensively consider various factors such as pipeline structure and load magnitude, making it difficult to provide a scientific and reasonable basis for blasting engineering construction. The research results have significant practical and engineering application value for solving technical development issues related to safety protection and disaster prevention in buried pipeline engineering; and they have important theoretical significance for enriching the prediction of PE gas pipeline vibration velocity.

[0051] (2) The present invention provides a numerical simulation method for predicting the vibration velocity of PE gas pipelines under explosive load. Different pipeline and load parameters are determined through experiments and relevant specifications, which has a wider range of applications and more reliable results. Attached Figure Description

[0052] Figure 1 This is a flowchart of the numerical simulation method for predicting the vibration velocity of a PE gas pipeline under blasting load according to the present invention;

[0053] Figure 2 A diagram of a PE pipeline blasting model in the numerical simulation method for predicting the vibration velocity of a PE gas pipeline under blasting load of the present invention.

[0054] In the diagram: 1-soil, 2-rock layer, 3-PE gas pipe, 4-blast hole, 5-explosive. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0056] Please refer to Figure 1 and Figure 2The present invention relates to a numerical simulation method for predicting the vibration velocity of PE gas pipelines under blasting loads. This method specifically includes the following steps:

[0057] S1: A PE pipeline blasting model is established using 3D simulation software, and the PE pipeline blasting model is meshed; the 3D simulation software is ANSYS analysis software; the PE pipeline blasting model includes a rock layer 2, soil 1 located on the rock layer, a PE gas pipe 3 located in the soil 1, and blast holes 4 arranged vertically and spaced apart from the PE pipeline 3, explosives 5 at the bottom of the blast, and rock and explosives plugging mud in the blast holes 4.

[0058] The specific process of establishing the PE pipeline burst model using 3D simulation software in step S1 is as follows:

[0059] S101. Based on the unique geological conditions of the urban area and the exploration and design data, investigate the characteristics and thickness of the soil and rock layers in the urban area, and establish a rectangular three-dimensional digital model at a 1:1 scale. The overall size of the three-dimensional digital model is 20m*10m*15m, of which the thickness of soil 1 is 4m and the thickness of rock layer 2 is 6m. Determine the size of the buried gas pipeline: a single pipe section is 10m long, 500mm in diameter, 45.5mm thick, and the internal pressure of the pipeline is 0.5MPa. Based on this, establish a pipeline numerical model, and set up a PE gas pipe 3 buried in soil 1 at a depth of 2m.

[0060] S102. Based on the typical engineering subway tunnel cross-section blasting construction data, the maximum single-section charge amount and the shortest distance to the buried PE gas pipeline are obtained, and the borehole and explosive models are established on the three-dimensional digital model; the borehole burial depth is set to 8m, the coupled charge is 12kg, and the explosive is No. 2 rock emulsion explosive.

[0061] In step S1, the mesh size is a crucial attribute affecting the accuracy of the simulation results. A mesh size that is too small leads to low computation speed and a high workload, while a large mesh size may produce unreliable results. Based on relevant research, the mesh size is set to be less than 1 / 8 to 1 / 10 of the wavelength. To ensure computational speed, the mesh size is determined after the model is built, taking into account both computation time and accuracy. In this embodiment, considering both computation time and accuracy, a mesh size of 5 cm is used.

[0062] S2: Based on the exploration and design data and indoor geotechnical dynamics tests, various material models based on dynamic parameters were set up in the PE pipeline blasting model.

[0063] In step S2, the selected material models include rock and explosive plugging material models, clay material models, explosive models, and pipe material models;

[0064] The model uses the *MAT_PLASTIC_KINEMATIC model for selecting the rock and explosive plugging materials. This model is suitable for selecting isotropic and kinematic hardening plasticity, including the rate effect. The equations for this material model are as follows:

[0065]

[0066] Where: σ y Let σ0 be the yield stress, σ0 be the initial yield stress, C and P be the strain rate parameters, and ε be the strain rate. For effective plastic strain, β is the hardening coefficient, and E P The equation for calculating the plastic hardening modulus is as follows:

[0067]

[0068] Where: E tan E is the tangent modulus, and E is Young's modulus.

[0069] The material selected in the soil material model is *MAT_DRUCKER_PRAGER, whose yield surface is determined by the friction angle and cohesion. A modified Drucker-Prager yield surface is used in this material model, distorting the surface shape to a more realistic soil definition. The yield surface model is represented as follows:

[0070]

[0071] Where: T is the shear strength, σ m φ is the average stress, φ is the internal friction angle, and c' is the cohesive force.

[0072] The explosive model is a rock emulsion explosive model, and the JWL equation of state for this rock emulsion explosive model is:

[0073]

[0074] Where: P is the relative specific volume of the detonation products, V is the pressure of the detonation products, E0 is the internal energy per unit volume, and R1, R2, A, B, and ω are material constants.

[0075] S3: Add model boundary conditions and related algorithm keywords to the PE pipeline blasting model. The related algorithm keywords include the automatic contact keyword between the pipeline and the soil layer, the explosive ALE algorithm keyword, and the keyword for defining and applying the internal pressure load curve of the pipeline.

[0076] In step S3, the methods for adding relevant keywords specifically include:

[0077] S301. In order to eliminate the reflection effect of the blasting stress wave generated by the explosive blasting at the model boundary, all boundary conditions except the upper surface of the model are set to non-reflection boundary conditions.

[0078] S302. To fully reflect the interaction between the pipe and the soil, the automatic contact keyword *CONTACT_AUTOMATIC_SURFACE_TO_SURFACE_TIEBREAK is set to simulate this.

[0079] S303. Locate the standard, determine the internal pressure load curve of the pipeline, define and apply it using *DEFINE_CURVE, then select the pipeline unit and apply the curve vertically to the inner wall of the pipeline.

[0080] S304. The ALE algorithm is selected to simulate the explosion and detonation process. This algorithm (Arbitrary Lagrange-Eulerian) means that the object can move arbitrarily in space within the grid. It is suitable for problems where the entire object has large spatial displacement and large deformation. This algorithm is set by adding the keyword *CONTROL_ALE.

[0081] S4: Based on the survey specifications and subway construction data, and using the PE pipeline blasting model in step S1, multiple PE pipeline blasting sub-models were established using orthogonal experimental theory. The PE pipeline blasting sub-models included multiple PE gas pipelines of different sizes, the maximum single-segment charge in subway tunnel blasting construction, and the relationship between the pipeline and the seismic source. Simulated blasting experiments were conducted using the above PE pipeline blasting sub-models to obtain multiple sets of experimental data.

[0082] S401. Based on the Urban Gas Design Code (GB50028-2008) and the Technical Specification for Polyethylene Gas Pipeline Engineering (CJJ 63-2008), determine the parameters for five diameters (Dn), five wall thicknesses (δ), and five internal pressures (P) of a PE100 pipeline; then, through research on construction data, determine the five maximum single-section charge amounts (Q), the five spatial distances between the seismic source and the pipeline (R), and the five pipeline burial depths (B) for tunnel and subway construction.

[0083] S402. Taking into account the numerical modeling under multiple factors and multiple levels of working conditions, based on the orthogonal experimental theory, by selecting some representative points from the comprehensive test, the following six-factor, five-level orthogonal experimental table is designed, taking into account the pipe diameter Dn, wall thickness δ, maximum single-section charge Q, detonation center distance R, burial depth B, and pipeline internal pressure P. The relevant working condition numerical models are established according to the working condition sequence number.

[0084] Orthogonal experimental design table for pipeline model

[0085]

[0086]

[0087] S5: Using dimensional analysis, a mathematical prediction model for pipeline vibration velocity is established. This model is then used to fit multiple sets of experimental data from step S4, yielding a prediction formula for the vibration velocity of buried polyethylene gas pipelines under blasting load, taking into account pipeline structure, blast center distance, explosive charge, and pipeline burial depth. The specific process is as follows: S501. Considering the relationship between pipeline vibration attenuation and various factors, using dimensionless analysis, the following physical relationship is assumed between pipeline vibration velocity and various influencing factors:

[0088] V p =Φ(Q,R,D,δ,B,P,ρ,c)

[0089] The physical meaning and dimensional representation of each parameter are shown in the table below:

[0090] Vibration velocity related parameters and dimensions diagram

[0091]

[0092]

[0093] Note: L—dimension of length; T—dimension of time; M—dimension of mass.

[0094] According to the homogeneity theorem of dimensions, if we choose Q, R, and c as dimensionless quantities and the other parameters as dimensionless quantities, we can obtain the dimensionless numbers as follows:

[0095]

[0096] Among them, π, π2, π3, π4, π5, and π6 are all dimensionless parameters;

[0097] Based on practical engineering considerations, when site conditions are constant, density and propagation speed can be approximated as constants.

[0098] set up

[0099]

[0100] The above formula can then be expressed as:

[0101]

[0102] Where β, β2, β3, β4, β5, and β6 are all fitting coefficients;

[0103] S502. Further, the calculation results of various numerical models established in S402 are statistically analyzed, and the maximum vibration velocity of the pipeline model is fitted using the prediction formula to obtain the vibration velocity prediction formula for buried polyethylene gas pipelines.

[0104] In this document, the directional terms such as front, back, top, and bottom are defined based on the location of the components in the accompanying drawings and their relative positions to each other, solely for the purpose of clarity and convenience in expressing the technical solution. It should be understood that the use of these directional terms should not limit the scope of protection claimed in this application.

[0105] Where there is no conflict, the above embodiments and features described herein can be combined with each other.

[0106] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A numerical simulation method for predicting the vibration velocity of a PE gas pipeline under blasting load, characterized in that: Specifically, the following steps are included: S1: Use 3D simulation software to establish a PE pipeline blasting model and mesh the PE pipeline blasting model; the PE pipeline blasting model includes a rock layer, soil on the rock layer, PE pipeline in the soil, and vertically arranged blast holes spaced apart from the PE pipeline, and explosives at the bottom of the blast. S2: Obtain the dynamic parameters of the materials in the PE pipeline blasting model based on the exploration and design data and indoor geotechnical dynamics tests; S3: Add model boundary conditions and related algorithm keywords to the PE pipeline blasting model. The related algorithm keywords include the automatic contact keyword between the pipeline and the soil layer, the explosive ALE algorithm keyword, and the keyword for defining and applying the internal pressure load curve of the pipeline. S4: Based on the survey specifications and subway construction data, and using the PE pipeline blasting model in step S1, multiple PE pipeline blasting sub-models were established using orthogonal experimental theory. The PE pipeline blasting sub-models included multiple PE gas pipelines of different sizes, the maximum single-segment charge in subway tunnel blasting construction, and the relationship between the pipeline and the seismic source. Simulated blasting experiments were conducted using the above PE pipeline blasting sub-models to obtain multiple sets of experimental data. S5: Using dimensional analysis, a mathematical prediction model for pipeline vibration velocity is established. The mathematical prediction model for pipeline vibration velocity is then used to fit multiple sets of experimental data from step S4 to obtain a prediction formula for the vibration velocity of buried polyethylene gas pipelines under blasting load, taking into account pipeline structure, blast center distance, explosive quantity, and pipeline burial depth. In step S5, the research method for predicting the vibration velocity of PE gas pipelines under blast load includes: S501: Considering the relationship between pipeline vibration attenuation and various factors, using the dimensionless analysis method, it is assumed that the pipeline vibration velocity and various influencing factors have the following physical relationship: Where Vp is the vibration velocity of the pipeline particles, Q is the maximum single-stage charge, R is the blasting distance, D is the pipeline diameter, δ is the pipeline wall thickness, B is the pipeline burial depth, P is the pipeline internal pressure, ρ is the pipeline density, and c is the wave propagation velocity in the medium. According to the homogeneity theorem of dimensions, select Q , R , c Given that the quantities are dimensionless and the other parameters are dimensionless, the dimensionless numbers are as follows: Where π, π2, π3, π4, π5, and π6 are dimensionless parameters, and L is the pipe length; Based on practical engineering considerations, when site conditions are constant, density and propagation speed can be approximated as constants. Where α3 and α4 are both fitting coefficients; The above formula can then be expressed as: Where β, β2, β3, β4, β5, and β6 are all fitting coefficients; S502: Further, the calculation results of various numerical models established in S402 are statistically analyzed, and the maximum vibration velocity of the pipeline model is fitted using the prediction formula to obtain the vibration velocity prediction formula for buried polyethylene gas pipelines.

2. The numerical simulation method for predicting the vibration velocity of a PE gas pipeline under blasting load as described in claim 1, characterized in that: The process of establishing a PE pipeline blasting model using 3D simulation software in step S1 is as follows: S101: Combining the unique geological conditions of the urban area, and based on the exploration and design data, investigate the characteristics and thickness of the soil and rock layers in the urban area, and establish a rectangular three-dimensional digital model at a 1:1 scale. S102: Based on the blasting construction data of typical subway tunnel sections, the maximum single-section charge amount and the shortest distance to the buried PE gas pipeline were obtained, and the borehole and explosive models were established on the three-dimensional digital model.

3. The numerical simulation method for predicting the vibration velocity of a PE gas pipeline under blasting load as described in claim 1, characterized in that: The mesh size of the PE pipe burst model after mesh generation is 5cm.

4. The numerical simulation method for predicting the vibration velocity of a PE gas pipeline under blasting load as described in claim 1, characterized in that, In step S2, the selected material model includes Rock and explosive plugging material models, soil material models, explosive models, and pipe material models; The rock and explosive plugging material models are as follows: in: For yield stress, The initial yield stress, C and P For strain rate parameters, ε For strain rate, For effective plastic strain, β The hardening coefficient, The equation for calculating the plastic hardening modulus is as follows: in: E tan Tangent modulus, E It is Young's modulus; The soil material model is as follows: in: T Shear strength, For average stress, φ It is the internal friction angle. c ' To gather strength; The explosive model is a rock emulsion explosive model, and the JWL equation of state for this rock emulsion explosive model is: in: P The relative specific volume of the detonation products. V The pressure of the detonation products, E 0 represents the internal energy per unit volume. R 1. R 2. A , B , ω is a material constant.

5. The numerical simulation method for predicting the vibration velocity of a PE gas pipeline under blasting load as described in claim 1, characterized in that: In step S3, the methods for adding relevant keywords include: S301: To eliminate the reflection effect of the blasting stress wave generated by the explosive blasting at the model boundary, all boundary conditions except the upper surface of the model are set to non-reflection boundary conditions. S302: To fully reflect the interaction between the pipeline and the soil layer, automatic surface-to-surface contact is simulated by setting up an automatic surface-to-surface contact mechanism. S303: Locate the standard, determine the peak pressure load inside the pipeline, define the load curve, then select the pipeline unit and apply the curve vertically to the inner wall of the pipeline. S304: Select the keyword to add control ALE algorithm to simulate the explosion and detonation process.

6. The numerical simulation method for predicting the vibration velocity of a PE gas pipeline under blasting load as described in claim 1, characterized in that, In step S4, the methods for determining the numerical model for different working conditions include: S401: Based on the Urban Gas Design Code and the Technical Specification for Polyethylene Gas Pipeline Engineering, five diameters are specified for a PE100 pipe. Dn Five wall thicknesses δ Five types of pipeline internal pressure P The parameters were determined; then, by investigating construction data, the maximum single-section explosive charge for tunnel and subway construction was determined. Q The spatial distance between the five types of seismic sources and the pipeline R and five types of pipeline burial depth B ; S402: Based on orthogonal experimental theory, representative points are selected from the comprehensive experiment for testing. Based on this, the pipe diameter is comprehensively considered. Dn Wall thickness δ Maximum single-stage charge Q , explosion center distance R burial depth B Pipeline internal pressure P The six factors and five levels of orthogonal 25 working conditions were used to establish numerical models of the relevant working conditions according to the working condition number.

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