A method for optimizing the safe distance between gas pipelines and subways based on numerical simulation

Abstract

The invention discloses a method for optimizing the safe distance between a gas pipeline and a subway based on numerical simulation, which relates to the field of subway tunnel safety technology, including: simulating gas pipeline explosion data through a KFX Exsim gas explosion model; establishing a fluid-solid coupling model, a soil dynamics model and a thermodynamic coupling model, and coupling the three to obtain a multi-physical field coupling model; based on the multi-physical field coupling model, combining a parallel computing framework to decompose and divide the numerical simulation tasks into regions, and simulating the impact of the gas pipe explosion on the subway; based on the numerical simulation results, evaluating the safety of the tunnel under the action of the explosion load; based on the safety evaluation results, optimizing the safe distance between the gas pipeline and the tunnel; the invention establishes a fluid-solid coupling model, a soil dynamics model and a thermodynamic coupling model, and couples the three to form a multi-physical field coupling model that comprehensively covers the explosion environment, thereby realizing an accurate simulation of the complex behavior of the subway tunnel under the explosion environment.

Description

Technical Field

[0001] The invention relates to the technical field of subway tunnel safety, and in particular to a method for optimizing a safe distance between a gas pipeline and a subway based on numerical simulation. Background Art

[0002] With the acceleration of urbanization, the development and utilization of urban underground space has become increasingly extensive. As important urban infrastructure, gas pipelines and subway tunnels are often closely distributed in underground space. However, the high-pressure transmission of gas pipelines and the characteristics of flammable gases may cause serious damage to adjacent subway tunnels when leaks or even explosions occur, including deformation of tunnel structures, lining failure, and operational safety risks.

[0003] The traditional design of safe distances between gas pipelines and subway tunnels mainly relies on empirical rules and regulatory requirements. However, although these methods guarantee safety to a certain extent, they fail to fully consider multiple factors such as complex geological conditions, explosion shock wave propagation mechanisms, and soil dynamic characteristics. Summary of the invention

[0004] In view of the above existing problems, the present invention is proposed.

[0005] Therefore, the present invention provides a method for optimizing the safe distance between gas pipelines and subways based on numerical simulation to solve the problem that the design of the safe distance between traditional gas pipelines and subway tunnels is not comprehensive enough.

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

[0007] In a first aspect, the present invention provides a method for optimizing the safe distance between a gas pipeline and a subway based on numerical simulation, which comprises:

[0008] Use KFX Exsim gas explosion model to simulate gas pipeline explosion data;

[0009] Establish a fluid-solid coupling model, a soil dynamics model and a thermodynamic coupling model, and couple the three to obtain a multi-physics field coupling model;

[0010] Based on the multi-physics field coupling model and the parallel computing framework, the numerical simulation tasks were decomposed and divided into regions to simulate the impact of gas pipe explosion on the subway.

[0011] Based on the numerical simulation results, the safety of the tunnel under blast loads is evaluated;

[0012] Based on the safety assessment results, optimize the safe distance between the gas pipeline and the tunnel.

[0013] As a preferred solution of the method for optimizing the safe distance between gas pipelines and subways based on numerical simulation described in the present invention, the gas pipeline explosion data is simulated by the KFX Exsim gas explosion model, and the specific steps are as follows:

[0014] After on-site investigation and design planning drawings of the tunnel and gas pipeline, the specific location of the explosion source was determined;

[0015] According to the location of the gas pipeline and the subway tunnel, the surrounding soil environment and the location of the explosion source, the KFX Exsim gas explosion model was constructed to simulate the gas pipeline explosion;

[0016] Output maximum explosion pressure, explosion shock wave velocity, explosion energy and temperature.

[0017] As a preferred solution of the method for optimizing the safe distance between gas pipelines and subways based on numerical simulation described in the present invention, the fluid-solid coupling model, soil dynamics model and thermodynamic coupling model are established, and the three are coupled to obtain a multi-physical field coupling model. The specific steps are as follows:

[0018] According to the maximum output explosion pressure, explosion shock wave velocity, explosion energy and temperature, fluid-solid coupling model, soil dynamics model and thermodynamic coupling model are established;

[0019] For the fluid-solid coupling model, the Cartesian coordinate system is used to divide the computational domain of the fluid-solid coupling model into the fluid region and the solid region;

[0020] Divide the meshes for tunnel, soil and air together and increase the mesh density at the flow-solid interface;

[0021] The fluid motion of the gas pipeline explosion shock wave is described by the Navier-Stokes equation;

[0022] The elastic-plastic deformation of the tunnel is described by the Drucker-Prager criterion;

[0023] For the soil dynamics model, the yield strength of soil under complex stress state is described by the Drucker-Prager elastoplastic criterion based on the introduction of dynamic loading rate effect.

[0024] For the thermodynamic coupling model, the Fourier heat conduction equation is used to describe the heat transfer inside the tunnel material.

[0025] The fluid-solid coupling model is coupled with the soil dynamics model through the interface stress transfer condition;

[0026] The thermodynamic coupling model is coupled with the soil dynamics model by adjusting the material parameters through the temperature field;

[0027] The decay of tunnel elastic modulus and yield strength is calculated by exponential decay formula;

[0028] The effect of fluid pressure wave will change the heat transfer coefficient of the tunnel surface. Through the combination of momentum equation and heat conduction equation, the fluid-solid coupling model is coupled with the thermodynamic coupling model.

[0029] Through the pairwise coupling of fluid-solid coupling model, soil dynamics model and thermodynamic coupling model, a multi-physics coupling model is obtained.

[0030] As a preferred solution of the method for optimizing the safe distance between gas pipelines and subways based on numerical simulation described in the present invention, the multi-physics field coupling model is combined with a parallel computing framework to decompose and divide the numerical simulation tasks into regions to simulate the impact of gas pipeline explosions on subways. The specific steps are as follows:

[0031] The impact of gas pipe explosion on subway is decomposed into four sub-tasks: explosion shock wave propagation, soil dynamic response, tunnel structure stress and thermal response;

[0032] The regional decomposition method is used to refine the calculation domain of the multi-physics field coupling model into high-gradient regions and low-gradient regions according to the gradients of pressure, temperature and stress.

[0033] The computational grid in the high gradient area is locally encrypted, and uniform grid division is used in the low gradient area;

[0034] A hybrid parallel computing framework based on MPI and CUDA is used to synchronize data and calculate the multi-physics field coupling model to simulate the impact of gas pipe explosion on the subway.

[0035] As a preferred solution of the method for optimizing the safe distance between gas pipelines and subways based on numerical simulation described in the present invention, the hybrid parallel computing framework based on MPI and CUDA is used to synchronize and calculate the multi-physical field coupling model. The specific steps are as follows:

[0036] Each subtask is calculated independently in high-gradient and low-gradient regions using explicit dynamic finite element method;

[0037] Using CUDA to solve the Navier-Stokes equations in parallel, the explosion shock wave propagation is calculated step by step based on the explicit time integration method;

[0038] The explicit finite element method is used to solve the Drucker-Prager yield criterion, and the soil dynamic response and tunnel structure stress are calculated step by step based on the stress deviator and strain rate.

[0039] The Fourier heat conduction equation is used to describe the heat transfer law inside the tunnel, and the thermal response is calculated step by step through the explicit time integration method;

[0040] At the fluid-solid interface, the high temperature environment is introduced to soften the tunnel surface, the heat conduction boundary conditions are dynamically adjusted, and the influence of the temperature field on the elastic modulus and yield strength of the tunnel material is dynamically updated;

[0041] Through MPI, the subtasks are synchronized and data integrated, the velocity and pressure of the fluid-solid interface are updated at the fluid-solid interface, and the normal stress, tangential stress and displacement continuity are synchronized at the tunnel soil interface;

[0042] The calculation results of high-gradient areas and low-gradient areas are integrated into a global solution, and the dynamic distribution of stress field, displacement field and temperature field of the tunnel during the gas pipe explosion is output.

[0043] As a preferred solution of the method for optimizing the safe distance between gas pipelines and subways based on numerical simulation described in the present invention, the safety of the tunnel under the action of explosion load is evaluated based on the numerical simulation results, and the specific steps are as follows:

[0044] According to the stress field distribution of the tunnel when the gas pipe explodes, the stress tensor of the grid is obtained;

[0045] By calculating the principal stress eigenvalues, the maximum principal stress, intermediate principal stress and minimum principal stress of the grid are obtained;

[0046] The peak value and corresponding position of the principal stress of each grid are recorded in the stress field distribution to form the maximum and minimum principal stress distribution diagram;

[0047] Based on the calculated maximum principal stress, intermediate principal stress and minimum principal stress, the principal strain of the mesh is calculated by generalized Hooke's law;

[0048] Summarize the principal strains of all grids to obtain the principal strain distribution diagram of the tunnel when the gas pipe explodes, record the peak value and position of the maximum principal strain, and form the maximum principal strain distribution diagram;

[0049] According to the geometric characteristics of the tunnel, the arch is taken as the concentrated impact point of normal stress, the side wall as the concentrated impact point of lateral shock wave, and the bottom plate as the concentrated impact point of reflected wave and shear stress;

[0050] From the displacement field distribution of the tunnel when the gas pipe explodes, the displacement values ​​of the vault, side wall and floor are extracted and decomposed into three directional components of the three-dimensional coordinates. The peak value and corresponding time point of each component are recorded to form a displacement field distribution diagram.

[0051] Based on the high temperature resistance of the tunnel, the critical temperature at which the tunnel performance decays is determined through high temperature testing and the temperature threshold is defined;

[0052] According to the dynamic distribution of the temperature field in the tunnel when the gas pipe explodes, the temperature value of each grid is obtained, all grids are screened, and the areas where the temperature exceeds the critical value are marked as thermal softening areas;

[0053] Generate a thermal softening area distribution map and superimpose it on the temperature field distribution map to intuitively display the softening range;

[0054] Combined with the tunnel material properties, the safety of the tunnel under blast loads is evaluated.

[0055] As a preferred solution of the method for optimizing the safe distance between gas pipelines and subways based on numerical simulation described in the present invention, the safety of the tunnel under the action of explosion load is evaluated by combining the tunnel material performance, and the specific steps are as follows:

[0056] The actual elastic modulus and yield strength of the tunnel are calculated by combining the temperature data of the temperature field distribution diagram through the exponential decay formula;

[0057] Recalculate the theoretical compressive strength and tensile strength of the tunnel based on the elastic modulus and yield strength recalculated according to the exponential decay formula and compare them with the maximum principal stress;

[0058] Compare the maximum displacement allowable values ​​of the arch, side wall and bottom plate given in the design during the construction of the subway tunnel with the maximum displacement values ​​of the arch, side wall and bottom plate in the three directions of the coordinate axis in the displacement field distribution diagram;

[0059] Combined with the simulation results of the heat conduction equation, the temperature distribution and time changes in the thermal softening area are analyzed. Through the temperature simulation data and combined with the thermal softening formula, the material properties are dynamically updated and the areas where the tunnel performance is attenuated are marked;

[0060] By conducting thermal fatigue tests on the tunnel's structural materials in a high temperature environment, we can obtain stress-life curves, fatigue parameters and thermal fatigue index;

[0061] The thermal fatigue life of the tunnel is calculated based on the number of cycles and the temperature variation range.

[0062] As a preferred solution of the method for optimizing the safe distance between the gas pipeline and the subway based on numerical simulation described in the present invention, the safe distance between the gas pipeline and the tunnel is optimized based on the safety assessment result, and the specific steps are as follows:

[0063] The optimization objectives are to minimize the tunnel pressure caused by the gas pipe explosion, maximize the ratio of the actual compressive strength of the tunnel structure to the maximum principal stress, and minimize the distance between the subway tunnel and the gas pipeline.

[0064] In the optimization process, the maximum principal stress of the tunnel lining is less than the compressive strength, the minimum principal stress is less than the tensile strength, the maximum temperature of the tunnel lining is less than the critical temperature of thermal softening, the maximum displacement of the tunnel vault, side wall and floor is less than the maximum allowable displacement value of the design, and the distance between the subway tunnel and the gas pipeline is greater than the minimum allowable distance of the design as constraints;

[0065] When the optimization result does not meet any constraint condition, it is considered that the optimization result does not meet the requirements and will not be adopted;

[0066] The horizontal distance between the gas pipeline and the tunnel, the buried depth of the gas pipeline, and the soil thickness between the gas pipeline and the subway tunnel were taken as design variables;

[0067] Discretize the design variables into several values ​​within the value range to generate design variable combinations;

[0068] The design variables are combined and input into the multi-physics coupling model for calculation to obtain the maximum and minimum principal stresses of the tunnel lining, the maximum temperature of the tunnel lining, and the maximum displacements of the tunnel vault, side wall and floor;

[0069] Record the optimization results corresponding to each set of design variables, and screen them according to the constraints, and delete the design variable combinations and corresponding optimization results whose optimization results do not meet the constraints; use genetic algorithms for multi-objective optimization, and use the design variable combinations as population individuals;

[0070] Use non-dominated sorting to sort the individuals in the population, select the Pareto frontier optimization result, compare the optimization results of each individual, and determine whether the optimization result is dominated by other individuals;

[0071] Select individuals from the Pareto frontier optimization results as the parents of the next generation population;

[0072] Perform a crossover operation on the linear combination of the design variable values ​​of any two parent individuals to generate two offspring individuals, and make any changes to the design variables of the offspring individuals within the value range;

[0073] For the newly generated population individuals, run the multi-physics field coupling model to perform numerical simulation, recalculate the optimization results, and update the Pareto frontier solution;

[0074] Through iterative optimization, when the maximum number of iterations is reached, the optimization is stopped;

[0075] From the Pareto frontier solution, the minimum optimization result value and the corresponding design variables are found to obtain the optimal horizontal distance between the gas pipeline and the tunnel, the buried depth of the gas pipeline, and the soil thickness between the gas pipeline and the subway tunnel.

[0076] In a second aspect, the present invention provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program is executed by the processor, any step of the method for optimizing the safe distance between a gas pipeline and a subway based on numerical simulation as described in the first aspect of the present invention is implemented.

[0077] In a third aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, it implements any step of the method for optimizing the safe distance between a gas pipeline and a subway based on numerical simulation as described in the first aspect of the present invention.

[0078] The beneficial effects of the present invention are as follows: by establishing a fluid-solid coupling model, a soil dynamics model and a thermodynamic coupling model, and coupling the three, a multi-physics field coupling model that comprehensively covers the explosion environment is formed, which realizes the accurate simulation of the complex behavior of the subway tunnel under the explosion environment, and significantly improves the simulation accuracy and reliability. By combining the multi-physics field coupling model with the parallel computing framework, not only the calculation speed is accelerated to ensure the high accuracy of the simulation results, but also a comprehensive assessment of the safety of the subway tunnel under the explosion load is carried out based on the numerical simulation results, which is helpful to discover safety hazards in advance, take preventive measures, and ensure the safety of subway operations. Based on the safety assessment results, a multi-objective optimization algorithm is used to determine the optimal safety distance between the gas pipeline and the subway tunnel, which solves important problems in actual engineering, and also provides a scientific basis for similar projects, promoting the safe utilization and development of urban underground space. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0080] Figure 1 This is a flow chart of the method for optimizing the safe distance between gas pipelines and subways based on numerical simulation in Example 1.

[0081] Figure 2 This is a synthetic diagram of the multi-physics field coupling model in Example 1. DETAILED DESCRIPTION

[0082] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0083] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0084] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0085] Example 1, reference Figure 1 and Figure 2 , which is the first embodiment of the present invention, provides a method for optimizing the safe distance between a gas pipeline and a subway based on numerical simulation, comprising the following steps:

[0086] S1. Use KFX Exsim gas explosion model to simulate gas pipeline explosion data.

[0087] After on-site investigation and design planning drawings of the tunnel and gas pipeline, the specific location of the explosion source was determined;

[0088] After on-site investigation and design planning drawings of the tunnel and gas pipeline, the specific location of the explosion source was determined;

[0089] In addition to methane, the main component of natural gas, there are also small amounts of ethane, propane, n-butane, isobutane, isopentane, N2 and CO2. Since the content of methane can generally reach about 90%, the study of natural gas leakage and diffusion process is simplified to the study of methane leakage and diffusion process;

[0090] According to the location of the gas pipeline and the subway tunnel, the main components of the gas, the surrounding soil environment and the specific location of the explosion source, the KFX Exsim gas explosion model was constructed to simulate the gas pipeline explosion;

[0091] Specifically, the gas leakage amount is determined according to the gas properties and state in the gas pipeline and the leakage aperture of the gas pipeline, and the formation of the leaking gas cloud is simulated;

[0092] First, determine the flow properties of the leaked gas, the expression is as follows:

[0093] ;

[0094] ;

[0095] in, is the environmental pressure, is the gas pressure in the pipeline, is the adiabatic index of the leaking gas;

[0096] When (1) holds true, it is a subsonic flow, and when (2) holds true, it is a sonic flow.

[0097] For subsonic flow, the gas leakage is calculated using the following expression:

[0098] ;

[0099] ;

[0100] in, is the gas leakage rate, is the crack shape coefficient, the circle is 1.00, the triangle is 0.95, and the rectangle is 0.90. is the gas leakage hole area, is the molecular weight of the fuel gas, is the universal gas constant, is the gas temperature;

[0101] For sonic flow, the gas leakage is calculated using the following expression:

[0102] ;

[0103] Based on the simulation of the leaking gas cloud, the explosion load is calculated using the TNO Multi-Energy Method (MEM);

[0104] Specifically, the TNO multi-energy method is a typical scaled explosion prediction model, which obtains a set of explosion intensity curves based on a large amount of experimental verification and numerical simulation data by assuming that the steam cloud is hemispherical and ignited at the center;

[0105] Output maximum explosion pressure, explosion shock wave velocity, explosion energy and temperature.

[0106] S2. Establish a fluid-solid coupling model, a soil dynamics model and a thermodynamic coupling model, and couple the three to obtain a multi-physics field coupling model.

[0107] According to the maximum output explosion pressure, explosion shock wave velocity, explosion energy and temperature, fluid-solid coupling model, soil dynamics model and thermodynamic coupling model are established;

[0108] For the fluid-solid coupling model, the Cartesian coordinate system is used to divide the calculation domain of the fluid-solid coupling model into the fluid area (explosion shock wave) and the solid area (tunnel);

[0109] The tunnel, soil and air are meshed together, and the mesh density is increased at the flow-solid interface to capture the detail changes;

[0110] The fluid motion of the gas pipeline explosion shock wave is described by the Navier-Stokes equation, and the expression is as follows:

[0111] ;

[0112] in, is the explosion shock wave density, is the partial derivative of the explosion shock wave velocity vector with respect to time, indicating the rate of change of the explosion shock wave velocity with time, is the explosion shock wave velocity vector, represents the velocity gradient of the explosion shock wave, For time, is the pressure gradient, which indicates the rate of change of pressure in space, is the dynamic viscosity, which characterizes the magnitude of the friction force in the explosion shock wave. The Laplace operator of the explosion shock wave velocity vector represents the spatial second-order derivative of the velocity field. is the volume force, such as gravity, inertia, etc.;

[0113] The elastic-plastic deformation of the tunnel is described by the Drucker-Prager criterion, which is expressed as follows:

[0114] ;

[0115] in, is the yield function of the material (tunnel), indicating whether the material (tunnel) is in an elastic or plastic state. , the material (tunnel) is in an elastic state, when , the material (tunnel) enters the plastic state, is the yield strength of the material (tunnel), is the second-order invariant of the stress deviator, that is, the intensity of the shear stress, is the yield surface control parameter, is the expansion coefficient of the material (tunnel), reflecting the expansion and compressibility of the material (tunnel). is the first stress invariant, i.e. the sum of the principal stresses, reflecting the spherical stress part;

[0116] At the fluid-solid interface, continuity and momentum balance conditions are imposed, i.e., continuity of velocity and normal stress is ensured;

[0117] Specifically, at the fluid-solid interface, at any instant, the velocity of the fluid particles is equal to the velocity of the solid nodes on the contact surface;

[0118] The normal stress on the interface remains continuous to satisfy the principle of conservation of momentum. For solids, it refers to the normal stress, and for fluids, it refers to the pressure, that is, ;

[0119] Shear stress continuity: The tangential stress of the fluid is equal to the tangential stress of the solid;

[0120] For the soil dynamics model, the yield strength of soil under complex stress state is described by the Drucker-Prager elastoplastic criterion based on the introduction of dynamic loading rate effect. The expression is as follows:

[0121] ;

[0122] in, is the yield function of the material (soil), indicating whether the material (soil) is in an elastic or plastic state. , the material (soil) is in an elastic state, when , the material (tunnel) enters the plastic state, is the yield strength of the material (soil), is the static shear strength of the soil, corresponding to the yield strength at a low loading rate, is the loading rate coefficient, reflecting the increase in yield strength caused by dynamic loading. is the strain rate;

[0123] For the thermodynamic coupling model, the Fourier heat conduction equation is used to describe the heat transfer inside the tunnel material. The expression is as follows:

[0124] ;

[0125] in, is the tunnel density, is the tunnel specific heat capacity, is the temperature gradient, is the tunnel thermal conductivity, Internal heat from gas pipe explosions;

[0126] The fluid-structure interaction model describes the effect of the gas pipe explosion pressure wave on the tunnel and its structural response, while the soil dynamics model describes the stress transfer from the tunnel structure to the surrounding soil and the nonlinear dynamic behavior of the soil;

[0127] Furthermore, the fluid-solid coupling model is coupled with the soil dynamics model through the interface stress transfer condition;

[0128] Specifically, at the interface between the tunnel and the surrounding soil, the normal stresses of the tunnel and the soil are equal, the tangential stresses of the tunnel and the soil are equal, and the displacements of the tunnel and the soil are equal;

[0129] The thermodynamic coupling model describes the effect of high temperature on tunnel material properties (e.g. elastic modulus, yield strength), while the soil dynamics model requires the use of tunnel material property parameters to calculate stress and deformation states;

[0130] The thermodynamic coupling model is coupled with the soil dynamics model by adjusting the material parameters through the temperature field;

[0131] Under the high temperature environment generated by the gas pipe explosion, the mechanical properties of the tunnel will produce a softening effect. The attenuation of the tunnel elastic modulus and yield strength is calculated using the exponential attenuation formula. The expression is as follows:

[0132] ;

[0133] ;

[0134] in, For the temperature When , the tunnel elastic modulus is is the initial tunnel elastic modulus (elastic modulus at room temperature), is the thermal softening coefficient of the tunnel elastic modulus, For the temperature When the tunnel yield strength is is the initial tunnel yield strength (yield strength at room temperature), is the thermal softening coefficient of the tunnel yield strength;

[0135] The pressure wave of the gas pipe explosion in the fluid-structure interaction model will impact and deform the tunnel structure, causing local temperature rise and affecting the heat transfer process of the material;

[0136] The effect of fluid pressure waves will change the thermal convection heat transfer coefficient on the tunnel surface and affect the thermal conduction boundary conditions. By combining the momentum equation and the heat conduction equation, the fluid-solid coupling model and the thermodynamic coupling model are coupled. The expression is as follows:

[0137] ;

[0138] in, Indicates the direction of the method. is the convective heat transfer coefficient, which describes the ability of fluid and solid to transfer heat through convection. is the temperature of the tunnel surface, The temperature generated by the explosion of the gas pipe;

[0139] Through the pairwise coupling of fluid-solid coupling model, soil dynamics model and thermodynamic coupling model, a multi-physics coupling model is obtained.

[0140] S3. Based on the multi-physics field coupling model and combined with the parallel computing framework, the numerical simulation tasks are decomposed and divided into regions to simulate the impact of the gas pipe explosion on the subway.

[0141] The impact of gas pipe explosion on subway is decomposed into four sub-tasks: explosion shock wave propagation, soil dynamic response, tunnel structure stress and thermal response;

[0142] The domain decomposition method (DDM) is used to divide the computational domain of the multi-physics coupling model.

[0143] According to the gradients of pressure, temperature and stress, the computational domain of the multi-physics coupling model is refined into high-gradient regions and low-gradient regions;

[0144] The high gradient area refers to the location close to the explosion source. After the explosion, the shock wave, temperature field and stress field change rapidly in this area. The pressure, temperature and stress gradients in this area are significant, showing a violent nonlinear characteristic.

[0145] Determine the scope of the high gradient area based on the explosion scale (gas leakage), medium characteristics (soil sound velocity, density) and geometric boundary conditions (such as the distance between the tunnel and the explosion source);

[0146] The computational grid in the high gradient area is locally encrypted, and uniform grid division is used in the low gradient area without the need for local encryption;

[0147] Furthermore, a hybrid parallel computing framework based on MPI (Message Passing Interface) and CUDA (Compute UnifiedDevice Architecture) was used to synchronize data and calculate multi-physics coupling models to simulate the impact of gas pipe explosions on subways;

[0148] Each subtask is calculated independently in high-gradient and low-gradient regions using explicit dynamic finite element method;

[0149] Using CUDA to solve the Navier-Stokes equations in parallel, the explosion shock wave propagation is calculated step by step based on the explicit time integration method. The expression is as follows:

[0150] ;

[0151] in, is the explicit time step, is the Courant number, is the grid cell size, is the wave speed;

[0152] The explicit finite element method is used to solve the Drucker-Prager yield criterion, and the soil dynamic response and tunnel structure stress are calculated step by step based on the stress deviator and strain rate.

[0153] The Fourier heat conduction equation is used to describe the heat transfer law inside the tunnel, and the thermal response is calculated step by step through the explicit time integration method;

[0154] At the fluid-solid interface, the high temperature environment is introduced to soften the tunnel surface, the heat conduction boundary conditions are dynamically adjusted, and the influence of the temperature field on the elastic modulus and yield strength of the tunnel material is dynamically updated;

[0155] Through MPI, the subtasks are synchronized and data integrated, the velocity and pressure of the fluid-solid interface are updated at the fluid-solid interface, and the normal stress, tangential stress and displacement continuity are synchronized at the tunnel-soil interface;

[0156] The calculation results of high-gradient areas and low-gradient areas are integrated into a global solution, and the dynamic distribution of stress field, displacement field and temperature field of the tunnel during the gas pipe explosion is output.

[0157] S4. Based on the numerical simulation results, the safety of the tunnel under blast load is evaluated.

[0158] For the pre- and post-processing of multi-physics field coupling models, the human-computer interaction pre- and post-processing module ABAQUS / CAE provided by ABAQUS is used to model, submit tasks, monitor the calculation process and post-processing results for ABAQUS / Standard or ABAQUS / Explicit problems;

[0159] ABAQUS has the Mohr-Coulomb model and Drucker-Prager model, which can truly reflect most of the stress-strain characteristics of materials and are suitable for simulating short-term or transient dynamic problems, such as structural response under impact and explosion loads.

[0160] According to the stress field distribution of the tunnel when the gas pipe explodes, the stress tensor of the grid is obtained in the form of a three-dimensional symmetric tensor, and the expression is as follows:

[0161] ;

[0162] in, is the stress tensor of the mesh, are the normal stresses along the coordinate axis, are the shear stresses in different planes;

[0163] By calculating the principal stress eigenvalues, the maximum principal stress, intermediate principal stress and minimum principal stress of the grid are obtained. The expressions are as follows:

[0164] ;

[0165] in, are the principal stress eigenvalues, is a 3×3 identity matrix, with elements on the diagonal being 1 and the rest being 0. Arrange by size to get the maximum principal stress , intermediate principal stress and minimum principal stress ;

[0166] The peak value and corresponding position of the principal stress of each grid are recorded in the stress field distribution to form the maximum and minimum principal stress distribution diagram, where when the principal stress is greater than 0, it indicates pressure, and when the principal stress is less than 0, it indicates tension;

[0167] Based on the calculated maximum principal stress, intermediate principal stress and minimum principal stress, the principal strain of the mesh is calculated by generalized Hooke's law, and the expression is as follows:

[0168] ;

[0169] in, As the main strain, is the elastic modulus of the tunnel material, is the Poisson's ratio of the tunnel material;

[0170] Furthermore, the principal strains of all grids are summarized to obtain the principal strain distribution diagram of the tunnel when the gas pipe explodes, and the peak value and position of the maximum principal strain are recorded to form the maximum principal strain distribution diagram;

[0171] According to the geometric characteristics of the tunnel, the arch is taken as the concentrated impact point of normal stress, the side wall as the concentrated impact point of lateral shock wave, and the bottom plate as the concentrated impact point of reflected wave and shear stress;

[0172] From the displacement field distribution of the tunnel when the gas pipe explodes, the displacement values ​​of the vault, side wall and floor are extracted and decomposed into three directional components of the three-dimensional coordinates. The peak value and corresponding time point of each component are recorded to form a displacement field distribution diagram.

[0173] Based on the high temperature resistance of the tunnel, the critical temperature at which the tunnel performance decays is determined through high temperature testing and the temperature threshold is defined;

[0174] According to the dynamic distribution of the temperature field in the tunnel when the gas pipe explodes, the temperature value of each grid is obtained, all grids are screened, and the areas where the temperature exceeds the critical value are marked as thermal softening areas;

[0175] Generate a thermal softening area distribution map and superimpose it on the temperature field distribution map to intuitively display the softening range;

[0176] The actual elastic modulus and yield strength of the tunnel are calculated by combining the temperature data of the temperature field distribution diagram through the exponential decay formula;

[0177] When the temperature rises, the internal molecular structure of the material changes, which is manifested as an exponential decrease in elastic modulus and yield strength;

[0178] The theoretical compressive strength and tensile strength of the tunnel are recalculated based on the elastic modulus and yield strength recalculated according to the exponential decay formula and compared with the maximum principal stress;

[0179] When the maximum principal stress is greater than the theoretical compressive strength, it means that the local area of ​​the tunnel exceeds the compressive limit and there is a risk of crushing. When the minimum principal stress is less than the theoretical tensile strength, it means that the local area of ​​the tunnel exceeds the tensile limit and there is a risk of cracking.

[0180] According to the maximum allowable displacement values ​​of the arch, side wall and bottom plate given in the design of subway tunnel construction, compare with the maximum displacement values ​​of the arch, side wall and bottom plate in the three directions of the coordinate axis in the displacement field distribution diagram;

[0181] If the displacement of the arch is too large, it will cause cracks in the lining or damage to ancillary equipment (such as cables). If the side wall displacement exceeds the limit, it will cause the lateral stability of the tunnel to fail. If the bottom plate displacement exceeds the limit, it means that the bearing capacity of the tunnel foundation is reduced.

[0182] Combined with the simulation results of the heat conduction equation, the temperature distribution and time changes in the thermal softening area are analyzed. Through the temperature simulation data and combined with the thermal softening formula, the material properties are dynamically updated and the areas where the tunnel performance is attenuated are marked;

[0183] By conducting thermal fatigue tests on the tunnel's structural materials under high temperature conditions, the stress-life curve and fatigue parameters were obtained. and thermal fatigue index ;

[0184] According to the number of cycles and temperature variation range, the thermal fatigue life of the tunnel is calculated as follows:

[0185] ;

[0186] in, is the thermal fatigue life of the tunnel, is the temperature difference between the maximum temperature and the normal temperature;

[0187] When the thermal fatigue life of a tunnel is less than the design life of the tunnel, it means that the service life of the tunnel will be reduced.

[0188] S5. Based on the safety assessment results, optimize the safe distance between the gas pipeline and the tunnel.

[0189] The optimization objectives are to minimize the tunnel pressure caused by the gas pipe explosion, maximize the ratio of the actual compressive strength of the tunnel structure to the maximum principal stress, and minimize the distance between the subway tunnel and the gas pipeline.

[0190] In the optimization process, the maximum principal stress of the tunnel lining is less than the compressive strength, the minimum principal stress is less than the tensile strength, the maximum temperature of the tunnel lining is less than the critical temperature of thermal softening, the maximum displacement of the tunnel vault, side wall and floor is less than the maximum allowable displacement value of the design, and the distance between the subway tunnel and the gas pipeline is greater than the minimum allowable distance of the design as constraints;

[0191] When the optimization result does not meet any constraint condition, it is considered that the optimization result does not meet the requirements and will not be adopted;

[0192] The horizontal distance between the gas pipeline and the tunnel, the buried depth of the gas pipeline, and the soil thickness between the gas pipeline and the subway tunnel were taken as design variables;

[0193] Discretize the design variables into several values ​​within the maximum value range required by the specification to generate design variable combinations;

[0194] The design variables are combined and input into the multi-physics coupling model for calculation to obtain the maximum and minimum principal stresses of the tunnel lining, the maximum temperature of the tunnel lining, and the maximum displacements of the tunnel vault, side wall and floor;

[0195] Record the optimization results corresponding to each set of design variables, and filter them according to the constraints, deleting the design variable combinations and corresponding optimization results whose optimization results do not meet the constraints;

[0196] Furthermore, a genetic algorithm (such as NSGA-II) is used for multi-objective optimization, and the design variable combinations are regarded as individuals in the population;

[0197] Use non-dominated sorting to sort the individuals in the population and select the Pareto frontier optimization result;

[0198] Compare the optimization results of each individual to determine whether the optimization results are dominated by other individuals;

[0199] Specifically, if the optimization result Q is better than the optimization result S in at least one objective and is not worse than S in all other objectives, then Q is said to dominate S;

[0200] When the optimization result A is not dominated by any other optimization result in the population, A is called a non-dominated optimization result;

[0201] All non-dominated optimization results constitute the first-level Pareto frontier optimization results and are removed from the population;

[0202] Repeat the non-dominated sorting for the remaining optimization results to form the second-level Pareto front optimization results, and remove them, and repeat the non-dominated sorting until all optimization results are assigned to a certain level of Pareto front optimization results;

[0203] Select individuals from the Pareto frontier optimization results as the parents of the next generation population;

[0204] The simulated binary crossover (SBX) method is used for crossover operation, and the design variable values ​​of any two parent individuals are linearly combined to generate two offspring individuals. The expression is as follows:

[0205] ;

[0206] ;

[0207] in, are the values ​​of the two generated offspring individuals on the design variable, are the values ​​of the two parent individuals on the design variables, is the similarity parameter;

[0208] The polynomial mutation method is used to arbitrarily change the design variables of the offspring individuals within the maximum value range required by the specification to increase population diversity;

[0209] For the newly generated population individuals, run the multi-physics field coupling model to perform numerical simulation, recalculate the optimization results, and update the Pareto frontier solution;

[0210] Through iterative optimization, when the maximum number of iterations is reached (e.g., 100 times, set according to the scale of the tunnel and the scale of the gas pipeline), the optimization is stopped;

[0211] From the Pareto frontier solution, the minimum optimization result value and the corresponding design variables are found to obtain the optimal horizontal distance between the gas pipeline and the tunnel, the buried depth of the gas pipeline, and the soil thickness between the gas pipeline and the subway tunnel.

[0212] This embodiment also provides a computer device, which is suitable for the case of a method for optimizing the safe distance between a gas pipeline and a subway based on numerical simulation, including: a memory and a processor; the memory is used to store computer executable instructions, and the processor is used to execute computer executable instructions to implement the method for optimizing the safe distance between a gas pipeline and a subway based on numerical simulation as proposed in the above embodiment.

[0213] The computer device may be a terminal, and the computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, an operator network, NFC (near field communication) or other technologies. The display screen of the computer device may be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device may be a touch layer covered on the display screen, or a key, trackball or touchpad provided on the housing of the computer device, or an external keyboard, touchpad or mouse, etc.

[0214] This embodiment also provides a storage medium on which a computer program is stored. When the program is executed by a processor, the method for optimizing the safe distance between a gas pipeline and a subway based on numerical simulation as proposed in the above embodiment is implemented; the storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as a static random access memory (SRAM), an electrically erasable programmable read-only memory (EEPROM), an erasable programmable read-only memory (EPROM), a programmable read-only memory (PROM), a read-only memory (ROM), a magnetic storage device, a flash memory, a disk or an optical disk.

[0215] In summary, the present invention establishes a fluid-solid coupling model, a soil dynamics model and a thermodynamic coupling model, and couples the three to form a multi-physics field coupling model that comprehensively covers the explosion environment, thereby achieving accurate simulation of the complex behavior of the subway tunnel under the explosion environment, and significantly improving the simulation accuracy and reliability. By combining the multi-physics field coupling model with the parallel computing framework, it not only speeds up the calculation speed and ensures the high accuracy of the simulation results, but also comprehensively evaluates the safety of the subway tunnel under the action of the explosion load based on the numerical simulation results, which is helpful to discover safety hazards in advance, take preventive measures, and ensure the safety of subway operations. Based on the safety assessment results, a multi-objective optimization algorithm is used to determine the optimal safety distance between the gas pipeline and the subway tunnel, which solves important problems in actual engineering, provides a scientific basis for similar projects, and promotes the safe utilization and development of urban underground space.

[0216] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for optimizing the safe distance between gas pipelines and subways based on numerical simulation, characterized in that: include, Use KFX Exsim gas explosion model to simulate gas pipeline explosion data; Establish a fluid-solid coupling model, a soil dynamics model and a thermodynamic coupling model, and couple the three to obtain a multi-physics field coupling model; Based on the multi-physics field coupling model and the parallel computing framework, the numerical simulation tasks were decomposed and divided into regions to simulate the impact of gas pipe explosion on the subway. Based on the numerical simulation results, the safety of the tunnel under blast loads is evaluated; Based on the safety assessment results, optimize the safe distance between the gas pipeline and the tunnel; Based on the multi-physics field coupling model, the numerical simulation task is decomposed and divided into regions in combination with the parallel computing framework to simulate the impact of the gas pipe explosion on the subway. The specific steps are as follows: The impact of gas pipe explosion on subway is decomposed into four sub-tasks: explosion shock wave propagation, soil dynamic response, tunnel structure stress and thermal response; The regional decomposition method is used to refine the calculation domain of the multi-physics field coupling model into high-gradient regions and low-gradient regions according to the gradients of pressure, temperature and stress. The computational grid in the high gradient area is locally encrypted, and uniform grid division is used in the low gradient area; A hybrid parallel computing framework based on MPI and CUDA is used to synchronize and calculate data for multi-physics coupling models to simulate the impact of gas pipe explosions on subways; Based on the numerical simulation results, the safety of the tunnel under the blast load is evaluated. The specific steps are as follows: According to the stress field distribution of the tunnel when the gas pipe explodes, the stress tensor of the grid is obtained; By calculating the principal stress eigenvalues, the maximum principal stress, intermediate principal stress and minimum principal stress of the grid are obtained; The peak value and corresponding position of the principal stress of each grid are recorded in the stress field distribution to form the maximum and minimum principal stress distribution diagram; Based on the calculated maximum principal stress, intermediate principal stress and minimum principal stress, the principal strain of the mesh is calculated by generalized Hooke's law; Summarize the principal strains of all grids to obtain the principal strain distribution diagram of the tunnel when the gas pipe explodes, record the peak value and position of the maximum principal strain, and form the maximum principal strain distribution diagram; According to the geometric characteristics of the tunnel, the arch is taken as the concentrated impact point of normal stress, the side wall as the concentrated impact point of lateral shock wave, and the bottom plate as the concentrated impact point of reflected wave and shear stress; From the displacement field distribution of the tunnel when the gas pipe explodes, the displacement values ​​of the vault, side wall and floor are extracted and decomposed into three directional components of the three-dimensional coordinates. The peak value and corresponding time point of each component are recorded to form a displacement field distribution diagram. Based on the high temperature resistance of the tunnel, the critical temperature at which the tunnel performance decays is determined through high temperature testing and the temperature threshold is defined; According to the dynamic distribution of the temperature field in the tunnel when the gas pipe explodes, the temperature value of each grid is obtained, all grids are screened, and the areas where the temperature exceeds the critical value are marked as thermal softening areas; Generate a thermal softening area distribution map and superimpose it on the temperature field distribution map to intuitively display the softening range; Combined with the tunnel material properties, evaluate the safety of the tunnel under blast loads; Based on the safety assessment results, the safe distance between the gas pipeline and the tunnel is optimized. The specific steps are as follows: The optimization objectives are to minimize the tunnel pressure caused by the gas pipe explosion, maximize the ratio of the actual compressive strength of the tunnel structure to the maximum principal stress, and minimize the distance between the subway tunnel and the gas pipeline. In the optimization process, the maximum principal stress of the tunnel lining is less than the compressive strength, the minimum principal stress is less than the tensile strength, the maximum temperature of the tunnel lining is less than the critical temperature of thermal softening, the maximum displacement of the tunnel vault, side wall and floor is less than the maximum allowable displacement value of the design, and the distance between the subway tunnel and the gas pipeline is greater than the minimum allowable distance of the design as constraints; When the optimization result does not meet any constraint condition, it is considered that the optimization result does not meet the requirements and will not be adopted; The horizontal distance between the gas pipeline and the tunnel, the buried depth of the gas pipeline, and the soil thickness between the gas pipeline and the subway tunnel were taken as design variables; Discretize the design variables into several values ​​within the value range to generate design variable combinations; The design variables are combined and input into the multi-physics coupling model for calculation to obtain the maximum and minimum principal stresses of the tunnel lining, the maximum temperature of the tunnel lining, and the maximum displacements of the tunnel vault, side wall and floor; Record the optimization results corresponding to each set of design variables, and filter them according to the constraints, deleting the design variable combinations and corresponding optimization results whose optimization results do not meet the constraints; Genetic algorithm is used for multi-objective optimization, and the combination of design variables is regarded as the individuals in the population; Use non-dominated sorting to sort the individuals in the population, select the Pareto frontier optimization result, compare the optimization results of each individual, and determine whether the optimization result is dominated by other individuals; Select individuals from the Pareto frontier optimization results as the parents of the next generation population; Perform a crossover operation on the linear combination of the design variable values ​​of any two parent individuals to generate two offspring individuals, and make any changes to the design variables of the offspring individuals within the value range; For the newly generated population individuals, run the multi-physics field coupling model to perform numerical simulation, recalculate the optimization results, and update the Pareto frontier solution; Through iterative optimization, when the maximum number of iterations is reached, the optimization is stopped; From the Pareto frontier solution, the minimum optimization result value and the corresponding design variables are found to obtain the optimal horizontal distance between the gas pipeline and the tunnel, the buried depth of the gas pipeline, and the soil thickness between the gas pipeline and the subway tunnel.

2. The method for optimizing the safe distance between a gas pipeline and a subway based on numerical simulation according to claim 1, characterized in that: The KFX Exsim gas explosion model is used to simulate gas pipeline explosion data. The specific steps are as follows: After on-site investigation and design planning drawings of the tunnel and gas pipeline, the specific location of the explosion source was determined; According to the location of the gas pipeline and the subway tunnel, the surrounding soil environment and the location of the explosion source, the KFX Exsim gas explosion model was constructed to simulate the gas pipeline explosion; Output maximum explosion pressure, explosion shock wave velocity, explosion energy and temperature.

3. The method for optimizing the safe distance between a gas pipeline and a subway based on numerical simulation according to claim 2, characterized in that: The fluid-solid coupling model, soil dynamics model and thermodynamic coupling model are established, and the three are coupled to obtain a multi-physics field coupling model. The specific steps are as follows: According to the maximum output explosion pressure, explosion shock wave velocity, explosion energy and temperature, fluid-solid coupling model, soil dynamics model and thermodynamic coupling model are established; For the fluid-solid coupling model, the Cartesian coordinate system is used to divide the computational domain of the fluid-solid coupling model into the fluid region and the solid region; Divide the meshes for tunnel, soil and air together and increase the mesh density at the flow-solid interface; The fluid motion of the gas pipeline explosion shock wave is described by the Navier-Stokes equation; The elastic-plastic deformation of the tunnel is described by the Drucker-Prager criterion; For the soil dynamics model, the yield strength of soil under complex stress state is described by the Drucker-Prager elastoplastic criterion based on the introduction of dynamic loading rate effect. For the thermodynamic coupling model, the Fourier heat conduction equation is used to describe the heat transfer inside the tunnel material; The fluid-solid coupling model is coupled with the soil dynamics model through the interface stress transfer condition; The thermodynamic coupling model is coupled with the soil dynamics model by adjusting the material parameters through the temperature field; The decay of tunnel elastic modulus and yield strength is calculated by exponential decay formula; Through the combination of momentum equation and heat conduction equation, the fluid-solid coupling model and the thermodynamic coupling model are coupled; Through the pairwise coupling of fluid-solid coupling model, soil dynamics model and thermodynamic coupling model, a multi-physics coupling model is obtained.

4. The method for optimizing the safe distance between a gas pipeline and a subway based on numerical simulation according to claim 3 is characterized in that: The hybrid parallel computing framework based on MPI and CUDA is used to synchronize and calculate the data of the multi-physics field coupling model. The specific steps are as follows: Each subtask is calculated independently in high-gradient and low-gradient regions using explicit dynamic finite element method; Using CUDA to solve the Navier-Stokes equations in parallel, the explosion shock wave propagation is calculated step by step based on the explicit time integration method; The explicit finite element method is used to solve the Drucker-Prager yield criterion, and the soil dynamic response and tunnel structure stress are calculated step by step based on the stress deviator and strain rate. The Fourier heat conduction equation is used to describe the heat transfer law inside the tunnel, and the thermal response is calculated step by step through the explicit time integration method; At the fluid-solid interface, the high temperature environment is introduced to soften the tunnel surface, the heat conduction boundary conditions are dynamically adjusted, and the influence of the temperature field on the elastic modulus and yield strength of the tunnel material is dynamically updated; Through MPI, the subtasks are synchronized and data integrated, the velocity and pressure of the fluid-solid interface are updated at the fluid-solid interface, and the normal stress, tangential stress and displacement continuity are synchronized at the tunnel soil interface; The calculation results of high-gradient areas and low-gradient areas are integrated into a global solution, and the dynamic distribution of stress field, displacement field and temperature field of the tunnel during the gas pipe explosion is output.

5. The method for optimizing the safe distance between a gas pipeline and a subway based on numerical simulation according to claim 4, characterized in that: The specific steps of evaluating the safety of the tunnel under blast load by combining the tunnel material performance are as follows: The actual elastic modulus and yield strength of the tunnel are calculated by combining the temperature data of the temperature field distribution diagram through the exponential decay formula; Recalculate the theoretical compressive strength and tensile strength of the tunnel based on the elastic modulus and yield strength recalculated according to the exponential decay formula and compare them with the maximum principal stress; Compare the maximum displacement allowable values ​​of the arch, side wall and bottom plate given in the design during the construction of the subway tunnel with the maximum displacement values ​​of the arch, side wall and bottom plate in the three directions of the coordinate axis in the displacement field distribution diagram; Combined with the simulation results of the heat conduction equation, the temperature distribution and time changes in the thermal softening area are analyzed. Through the temperature simulation data and combined with the thermal softening formula, the material properties are dynamically updated and the areas where the tunnel performance is attenuated are marked; By conducting thermal fatigue tests on tunnel structural materials in high temperature environments, stress-life curves, fatigue parameters and thermal fatigue indexes were obtained; The thermal fatigue life of the tunnel is calculated based on the number of cycles and the temperature variation range.

6. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method for optimizing the safe distance between a gas pipeline and a subway based on numerical simulation as described in any one of claims 1 to 5 are implemented.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for optimizing the safe distance between a gas pipeline and a subway based on numerical simulation as described in any one of claims 1 to 5 are implemented.

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