Personnel evacuation simulation method and system under flood spreading condition aiming at underground scene

Abstract

The invention discloses a method and a system for simulating personnel evacuation under the flood spreading situation of an underground scene, and the method comprises the steps: building an underground scene model, simulating the flood spreading process of the underground scene model, obtaining the flood dynamic information of each position point in the underground scene model, and carrying out the simulation of the flood spreading process of the underground scene model; the flood dynamic information comprises flood water depth, flow velocity and flow direction; gridding the space in the underground scene model, and determining an initial pedestrian position; building a static field, a water depth field, a support field and a flow velocity field based on the cellular automaton, and further calculating the transition probability of pedestrians; judging the human body stability of the pedestrian based on the flood dynamic information, and calculating the moving speed of the pedestrian; and updating the pedestrian position based on the transition probability and the pedestrian moving speed, and finely simulating the evacuation of the pedestrian in the underground scene in the flood spreading process. According to the invention, the movement stability and movement speed of pedestrians in flood are considered, which is beneficial for studying how to evacuate crowds timely, efficiently and safely under the flood situation.

Description

Technical Field

[0001] The present invention relates to the technical field of computer simulation, and in particular to a method and system for simulating the evacuation of personnel from a subway station under the condition of flood spread. Background Art

[0002] In recent years, extreme precipitation events have occurred frequently around the world, manifested in rising temperatures and frequent extreme weather events. At the same time, more and more underground transportation systems have entered people's daily lives, causing a sharp expansion of impermeable surfaces in cities, blocking drainage systems in cities, and causing subway stations or lines to be flooded in many cities. If a flood disaster occurs, the people in the station cannot be evacuated in time, which will cause serious casualties. Therefore, it is necessary to explore how to evacuate people in subway stations in a timely, efficient and safe manner under flood conditions.

[0003] The micro-simulation system simulates the crowd dynamics model under the condition of flood spreading in subway stations, explores the traffic operation rules and vehicle behavior characteristics in the simulation process, and provides an experimental platform for related research such as urban road traffic management planning.

[0004] The existing microscopic evacuation models for studying pedestrian evacuation models can be divided into continuous models and discrete models. The social force model is a typical continuous model, and the discrete models include the lattice gas model and the cellular automaton model. Due to the high complexity and particularity of pedestrian movement in floods, the social force model and the lattice gas model cannot accurately reflect these complex behavioral characteristics, and the current cellular automaton model does not fully consider the impact of flood factors on crowd movement and behavioral decision-making.

[0005] When existing cellular automata models simulate the movement of pedestrians in floods, the evacuation process of subway stations under floods usually assumes flood parameters such as water depth and flow rate, mainly considering the impact of water depth on evacuation speed, ignoring the impact of water flow speed and direction on crowd movement and behavioral decisions. In addition, in the existing research on crowd evacuation modeling in flood scenarios, most of the focus is on two-dimensional plane channels, while ignoring the bottleneck area of ​​three-dimensional stairs. At the same time, few studies consider instability conditions in floods. In summary, the flood spreading process in existing cellular automata models is mainly based on assumptions, and the impact of flood factors on crowd movement and behavioral decisions is not fully considered. The evacuation characteristics of pedestrians under flood conditions in subway stations are still unclear. Summary of the invention

[0006] In order to address the deficiencies in the prior art, the present application proposes a method and system for simulating the evacuation of people in underground scenes under flood spreading conditions, which fully considers factors such as the stability and speed of pedestrians moving in floods, and is conducive to studying how to evacuate people in underground scenes in a timely, efficient and safe manner under flood situations.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A method for simulating personnel evacuation in the event of flood spreading in an underground scene, comprising the following steps:

[0009] S1, building an underground scene model to be analyzed, simulating the flood spreading process of the underground scene model, and obtaining flood dynamic information at each location point in the underground scene model, wherein the flood dynamic information includes flood water depth, flow velocity, and flow direction;

[0010] S2, gridding the space in the underground scene model and determining the initial pedestrian position;

[0011] S3, based on cellular automata, constructs static field, water depth field, support field, and flow velocity field, and then calculates the pedestrian's transfer probability P i,j , expressed as:

[0012]

[0013] Where N is the normalization parameter, k S , k H , k U , k F They are the weight coefficients of static field, water depth field, support field, and flow velocity field; represents the dimensionless static field value, represents the dimensionless water depth field value, represents the dimensionless support field value, represents the dimensionless velocity field; η i,j Indicates whether the cell is occupied by pedestrians, if so, it is assigned 1, otherwise it is 0; α i,j Indicates whether it is occupied by a wall or obstacle, if so, it is assigned a value of 0, otherwise, it is 1;

[0014] S4, based on the flood dynamic information in S1, judge the stability of pedestrians and calculate the pedestrian moving speed V p , expressed as:

[0015]

[0016] Where M is the specific flood force per unit width, V pc represents the speed of pedestrians on the platform under flood conditions, V ps represents the speed of pedestrians on the stairs without water, V f is the water velocity;

[0017] S5, based on the transition probability P i,j , pedestrian moving speed V pUpdate the positions of pedestrians and simulate the evacuation of pedestrians in underground scenes during the flood spread process.

[0018] Furthermore, the MIKE21 two-dimensional hydrodynamic model was used to simulate the flood spreading process of the underground scene model.

[0019] Furthermore, the method for simulating flood spreading of underground scene model is as follows:

[0020] S1.1, build an underground scene model using MIKE21 according to the spatial structure of the underground scene to be analyzed;

[0021] S1.2, using the data extraction tool Mike2Txt of the MIKE software, the flood dynamic information of each grid point in the underground scene model at each time step is obtained, including key information such as water depth, flow velocity, and flow direction.

[0022] Further, the process of S2 is as follows:

[0023] S2.1, the underground scene is discretized based on cellular automata, and the spatial grid in the underground scene is consistent with the flood simulation scene;

[0024] S2.2, use simulation software to construct structures representing pedestrians or obstacles in the space of the underground scene.

[0025] Furthermore, the static field S i,j It is used to describe the distance from the cell to the exit. The field value increases along the exit direction and reaches the maximum at the exit. It is expressed as:

[0026]

[0027] Among them, (i, j) represents the coordinates of the cell in the space, (i e , j e ) represents the coordinates of the exit cell, (i l , j l ) represents the coordinates of any cell in space, d max is the maximum distance of any cell from the exit in the space, x,y∈[-1,1]; Represents the dimensionless static field value; max(S i+x,j+y ) is the maximum value of the static field in cell (i, j) and its eight adjacent cells.

[0028] Furthermore, the water depth field H i,j It is used to describe the effect of water depth on pedestrian movement. The field value is designed to be inversely proportional to the water depth, expressed as:

[0029] H i,j =H max -h i,j

[0030]

[0031] Among them, h i,j represents the water depth at cell (i, j), H max Represents the critical water depth for people to walk in water, Represents the dimensionless water depth field value; max(H i+x,j+y ) is the maximum value of the water depth field in cell (i, j) and its eight adjacent cells.

[0032] Furthermore, the support field is used to characterize the influence of the support on the movement of personnel. The value of the support field increases with the increase of water depth, which is expressed as:

[0033]

[0034]

[0035] Among them, U' i,j To describe the distance from the support to the exit, (i U , j U ) represents the cell coordinates where the support is located, d Umax Represents the maximum distance between any cell in space and the support. represents the dimensionless support field value; max(U i+x,j+y ) is the maximum value of the support field in cell (i, j) and its eight adjacent cells.

[0036] Furthermore, the velocity field F i,j It is used to describe the impact of flood velocity and direction on pedestrian movement, expressed as:

[0037]

[0038]

[0039] in, represents the magnitude and direction of the flow velocity in the cell, is a unit vector, F i,j represents the projection of the flow velocity on the cell (i, j), represents the dimensionless velocity field, max(F i+x,j+y ) is the maximum value of the velocity field in cell (i, j) and its eight adjacent cells.

[0040] Furthermore, the thresholds of flow velocity or water depth at different locations are used to judge whether pedestrians are unstable in waterlogging disasters, which can be expressed as:

[0041] On the platform:

[0042] (1)V fh≥1.2m 2 / s

[0043] (2) V f ≥2.6m / s

[0044] (3)h≥1.1m

[0045] On the stairs:

[0046]

[0047] Where V f is the water velocity and h is the water depth.

[0048] A simulation system for evacuating people from a subway station under flood spreading conditions, used to implement the above-mentioned simulation method for evacuating people under flood spreading conditions for underground scenes, the system comprising a parameter definition module, a flood spreading module and a pedestrian position update module;

[0049] The parameter definition module is used to build the underground scene model, establish the grid coordinate system of the underground scene model, and define the cell size after fine grid division, the time step length, the positions occupied by pedestrians and obstacles in the subway grid coordinate system, and the pedestrian movement speed;

[0050] The flood spread module is equipped with the MIKE21 two-dimensional hydrodynamic model, which is used to simulate the movement of water bodies in flood events and can generate real-time data on water depth, flow velocity and flow direction in the flooded area;

[0051] The pedestrian position update module is used to quantify the impact of floods on pedestrian movement. It integrates the flood dynamic information provided by the flood spread module and considers the influencing factors of water depth, flow velocity and flow direction on the direction and speed of pedestrian movement.

[0052] Beneficial effects of the present invention:

[0053] (1) The present invention combines professional flood simulation software and cellular automaton model to establish a subway station personnel evacuation model under flood spreading conditions, which can accurately simulate the flood spreading process of subway stations and the movement characteristics of pedestrians.

[0054] (2) The present invention calculates the transfer probability of the target cell based on the cellular automaton model. In addition, it also comprehensively considers the stability and movement speed of pedestrians in floods to ensure the accuracy and practicality of the simulation. Specifically, the present invention calculates the transfer probability of the target cell to predict the position choice of pedestrians at each time step. At the same time, it considers the impact of the flood environment on the stability of pedestrian movement and introduces instability parameters to simulate the evacuation of pedestrians in floods. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is a flow chart of the present invention;

[0056] Figure 2 A schematic diagram of the pedestrian neighboring cells and transition probabilities according to the present invention;

[0057] Figure 3 This is a schematic diagram of the subway platform layer of the present invention;

[0058] Figure 4 The interactive relationship between the flood spreading model and the pedestrian evacuation model of the present invention;

[0059] Figure 5 This is a flow chart of the model simulation described in the present invention. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0061] like Figure 1 As shown, a method for simulating personnel evacuation in a flood spreading situation in an underground scene includes the following steps:

[0062] S1, for the underground scene to be analyzed, first build the underground scene model, and simulate the flood spreading process of the underground scene model, and calculate the flood dynamic information at each grid point in the underground scene model, wherein the flood dynamic information includes flood water depth, flow velocity, and flow direction.

[0063] The specific process of using the MIKE21 two-dimensional hydrodynamic model to simulate flood spreading in step S1 is as follows:

[0064] S1.1, use MIKE21 to build an underground scene model according to the spatial structure of the underground scene to be analyzed.

[0065] The present invention is mainly aimed at underground transportation facilities where the population is densely distributed, such as subway stations, underground tunnels, etc. Figure 3The platform layer of a typical island station shown in the figure is used as a simulation scenario. The length of the platform is 108.5m and the width is 23m. Two B-type subway trains are used in the simulation, each consisting of 6 carriages, to simulate the up and down operations of the trains. There are staircase exits on both sides of the platform, the width of the entrance and exit is defined as W (unit: m), and the length is defined as L (unit: m), where W is 3.5m and L is 12m. In the simulated emergency situation, that is, when the flood spreads, consider setting one side of the stairs as the entrance and exit and the other side of the stairs as the evacuation exit. The personnel evacuation preparation time t is defined as the time from the beginning of the flood spread to the time when the personnel begin to evacuate to the exit, and the pedestrian evacuation time T is the time from the beginning of the evacuation to the end of all evacuations. The number of pedestrians initially set is N, of which 80% are randomly distributed in the subway train and the remaining 20% ​​are distributed on the platform. To simplify the calculations, the model simulation is based on two main assumptions: first, when a subway platform encounters flooding, the train will stop running and park inside the station with all doors open; second, this simulation only considers flooding and does not consider the drainage capacity of the subway station.

[0066] When simulating the flooding of subway stations, considering that the subway station is a semi-enclosed underground space, flooding usually occurs at the entrance and exit. Therefore, in this simulation, in order to simulate the most likely flood intrusion point in reality, the left staircase of the subway station is set as the water inlet.

[0067] S1.2, using the data extraction tool Mike2Txt of the MIKE software, the flood dynamic information of each grid point in the underground scene model at each time step is obtained, including key information such as water depth, flow velocity, and flow direction.

[0068] It should be noted that the MIKE series of hydrodynamic software was developed by the Danish Hydraulics Institute (DHI), and MIKE21 is a two-dimensional hydrodynamic model in the series, which is widely used to simulate the changes in water level and flow velocity in rivers, lakes, estuaries and other water bodies. The MIKE series of hydrodynamic software can grid the space and calculate each grid point, and can easily, quickly and accurately output the change data of water flow and water level.

[0069] S2, based on the underground scene model, grids the space in the subway station and determines the initial pedestrian position; S2 includes the following specific steps:

[0070] S2.1, the present invention evacuates people in subway station scenes, so the above subway station scenes are evacuation scenes; the evacuation scenes are discretized based on cellular automata, and in order to make the grid consistent with the MIKE21 flood simulation scene, and combined with the average shoulder width data of the human body, the cell size is set to 0.5m×0.5m, and the space in the subway station is gridded.

[0071] S2.2, use MATLAB to construct a structure in the subway station space, name the structure Grid, and create multiple fields for the structure (such as Grid.obstacle) to store grid data (such as obstacle matrix). Since the subway platform is 108.5m long, 23m wide, and the cell size is 0.5m×0.5m, the capacity of each field of the structure is set to 217 cells long and 46 cells wide. Taking Grid.obstacle as an example, this field stores the position of obstacles in the subway station. In the calculation of pedestrian movement probability, αi,j represents whether it is occupied by a wall or obstacle. If the position of Grid.obstacle(i,j) is occupied by a wall or obstacle, then αi,j=1, otherwise it is 0.

[0072] S3, based on cellular automata, constructs static field (SFF), water depth field (HFF), support field (UFF), and flow velocity field (FFF), and then calculates the pedestrian's transfer probability P i,j A cellular automaton is a dynamic system that evolves in a discrete time dimension based on fixed local rules in a discrete cellular space, where the cells have discrete and finite states. In this system, the space is divided into multiple units through a regular grid of a specific form, each unit is called a cell, and they only take values ​​in a finite set of discrete states.

[0073] S3.1, in this application, the static field (SFF), water depth field (HFF), support field (UFF), and flow velocity field (FFF) are respectively represented as follows:

[0074] a: static field S i,j Describes the distance from the cell to the exit. The field value increases along the exit direction and reaches the maximum at the exit. The calculation formula is as follows:

[0075]

[0076] Among them, (i, j) represents the coordinates of the cell in the space, (i e , j e ) represents the coordinates of the exit cell, (i l , j l ) represents the coordinates of any cell in space, d max is the maximum distance of any cell from the exit in the space, x,y∈[-1,1]; Represents the dimensionless static field value; max(S i+x,j+y ) is the maximum value of the static field in cell (i, j) and its eight adjacent cells.

[0077] b: Water depth field H i,jDescribes the effect of water depth on pedestrian movement. Considering that pedestrians usually avoid deep water areas and move to shallower water areas, the field value is designed to be inversely proportional to the water depth, that is, the deeper the water, the smaller the field value. The calculation formula is as follows:

[0078] H i,j =H max -h i,j (4)

[0079]

[0080] Among them, h i,j represents the water depth at cell (i, j), H max The critical water depth for people to walk in water is about 0.7m. Represents the dimensionless water depth field value; max(H i+x,j+y ) is the maximum value of the water depth field in cell (i, j) and its eight adjacent cells.

[0081] c: Support field U i,j Describe the impact of supports on people's movement. In flood situations, pedestrians tend to look for objects such as walls and handrails for support to maintain balance and stability. As the water depth increases, people's dependence on these supports also increases accordingly. Therefore, the value of the support field will increase with the increase of water depth. The calculation formula is as follows:

[0082]

[0083] Among them, U' i,j To describe the distance from the support to the exit, (i U , j U ) represents the cell coordinates where the support is located, d Umax Represents the maximum distance between any cell in space and the support. represents the dimensionless support field value; max(U i+x,j+y ) is the maximum value of the support field in cell (i, j) and its eight adjacent cells.

[0084] d: Flow velocity field F i,j Describes the impact of flood flow velocity and direction on pedestrian movement. The flow of flood water can assist or hinder the movement of people, depending on the magnitude of the flow velocity and its direction. The calculation formula is as follows:

[0085]

[0086] in, represents the magnitude and direction of the flow velocity in the cell, is a unit vector, F i,j represents the projection of the flow velocity on the cell (i, j), represents the dimensionless velocity field, max(F i+x,j+y ) is the maximum value of the velocity field in cell (i, j) and its eight adjacent cells.

[0087] S3.2, based on the static field, water depth field, support field, and flow velocity field, calculate the transfer probability P of pedestrians moving to adjacent cells i,j , the formula is as follows:

[0088]

[0089] Where N is the normalization parameter to ensure that ∑P i,j =1; k S , k H , k U , k F are the weight coefficients of static field, water depth field, support field and flow velocity field respectively; η i,j Indicates whether the cell is occupied by pedestrians, if yes, it is 1, otherwise, it is 0; α i,j Indicates whether it is occupied by a wall or obstacle, if so, it is 0, if not, it is 1.

[0090] like Figure 2 As shown in Figure 2, the model simulates the movement of pedestrians during the evacuation process. It uses Moore's neighborhood. Each cell has 8 adjacent cells. Pedestrians can move horizontally, vertically, and diagonally. At each moment, the probability of pedestrians moving to adjacent cells is marked in Figure 2 middle.

[0091] S4, based on the flood dynamic information in S1, judge the stability of the pedestrian's body and calculate the pedestrian's moving speed V p ;

[0092] S4.1, determine whether pedestrians are unstable during flood disasters based on flood dynamic information.

[0093] The degree of danger to pedestrians in flood disasters can be quantitatively reflected by the stability of the human body in the flood. Specifically, when the flow rate or water depth exceeds the threshold, the individual will lose balance and stability. According to the "Guidelines for the Preparation of Urban Flood Control Emergency Plans: SL754-2017" and previous studies, the critical conditions for pedestrian instability are given as follows:

[0094] On the platform:

[0095] V f h≥1.2m 2 / s;

[0096] V f ≥2.6m / s; (13)

[0097] h≥1.1m

[0098] On the stairs:

[0099]

[0100] Where V f is the water velocity, h is the water depth. Once the pedestrian at (i, j) satisfies the above two instability conditions, the pedestrian motion at the cell (i, j) is only affected by the velocity field in formula (12), that is, k S =k H =k U =0.

[0101] S4.2, calculate the pedestrian moving speed V p The formula is as follows:

[0102]

[0103] Where V pc represents the speed of pedestrians on the platform under flood conditions, which is set to 1.5 m / s; V ps represents the speed of pedestrians on the stairs without water, which is set to 0.7 m / s, M is the flood force per unit width, g is the acceleration of gravity, V f is the water velocity and h is the water depth.

[0104] S5, based on the transition probability P i,j , pedestrian moving speed V p Update the positions of pedestrians and simulate the evacuation of pedestrians in underground scenes during the flood spread process.

[0105] The interactive relationship between the flood spreading model and the pedestrian evacuation model is as follows: Figure 4 As shown, the present application combines the flood spreading process with the pedestrian movement process, and considers the influencing factors of water depth, flow velocity, and flow direction on the pedestrian movement direction and speed by integrating the data provided by the flood spreading model.

[0106] The specific process is as follows Figure 5 As shown in the figure, first, the model checks whether each pedestrian has reached the safe exit in each simulation time step. If the pedestrian has not reached the exit, the model further determines whether the pedestrian is unstable. The basis for judging instability includes water depth and flow velocity. For pedestrians who are not unstable, the transition probability P is calculated based on four key fields: static field (SFF), water depth field (HFF), support field (UFF) and flow velocity field (VFF). i,j ; For unstable pedestrians, the transition probability P is calculated based only on the velocity field (VFF) i,j , which means that the person will be pushed by the water flow and cannot choose the direction of movement independently. Then, the model calculates the pedestrian's movement speed V according to environmental factors and pedestrian status. p, which aims to simulate the moving speed of pedestrians in different water depths. Finally, based on the calculated transition probability P i,j and the movement speed V p , the pedestrian moves to the target cell.

[0107] In order to realize the above-mentioned personnel evacuation simulation method under the flood spreading situation for underground scenes, the present application also proposes a subway station personnel evacuation simulation system under the flood spreading situation, the system includes a parameter definition module, a flood spreading module and a pedestrian position update module;

[0108] The parameter definition module is used to build the underground scene model, establish the grid coordinate system of the underground scene model, and define the cell size after fine grid division, the time step length, the positions occupied by pedestrians and obstacles in the subway grid coordinate system, and the pedestrian movement speed;

[0109] The flood spread module, equipped with the MIKE21 planar two-dimensional hydrodynamic model, is used to simulate the movement of water bodies in flood events and can generate real-time water depth, flow velocity and flow direction data for flooded areas.

[0110] The pedestrian position update module is used to quantify the impact of floods on pedestrian movement. It integrates the flood dynamic information provided by the flood spread module and considers the influencing factors of water depth, flow velocity and flow direction on the direction and speed of pedestrian movement.

[0111] The above embodiments are only used to illustrate the design ideas and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, any equivalent changes or modifications made based on the principles and design ideas disclosed by the present invention are within the protection scope of the present invention.

Claims

1. A method for simulating personnel evacuation in the event of flooding in underground scenes, characterized in that: The steps include: S1, building an underground scene model to be analyzed, simulating the flood spreading process of the underground scene model, and obtaining flood dynamic information at each location point in the underground scene model, wherein the flood dynamic information includes flood water depth, flow velocity, and flow direction; S2, gridding the space in the underground scene model and determining the initial pedestrian position; S3, based on cellular automata, constructs static field (SFF), water depth field (HFF), support field (UFF), and flow velocity field (FFF), and then calculates the pedestrian's transfer probability P i,j , expressed as: Where N is the normalization parameter, k S , k H , k U , k F They are the weight coefficients of static field, water depth field, support field, and flow velocity field; represents the dimensionless static field value, represents the dimensionless water depth field value, represents the dimensionless support field value, represents the dimensionless velocity field; η i,j Indicates whether the cell is occupied by pedestrians, if so, it is assigned 1, otherwise it is 0; α i,j Indicates whether it is occupied by a wall or obstacle, if so, it is assigned a value of 0, otherwise, it is 1; S4, based on the flood dynamic information in S1, judge the stability of pedestrians and calculate the pedestrian moving speed V p , expressed as: Where M is the specific flood force per unit width, V pc represents the speed of pedestrians on the platform under flood conditions, V ps represents the speed of pedestrians on the stairs without water, V f is the water velocity; S5, based on the transition probability P i,j , pedestrian moving speed V p Update the positions of pedestrians and simulate the evacuation of pedestrians in underground scenes during the flood spread process.

2. The method for simulating personnel evacuation in a flood spreading situation for an underground scene according to claim 1, characterized in that: The MIKE21 two-dimensional hydrodynamic model is used to simulate the flood spreading process of the underground scene model.

3. The method for simulating personnel evacuation in a flood spreading situation for an underground scene according to claim 2, characterized in that: The method for simulating flood spread in underground scene models is: S1.1, build an underground scene model using MIKE21 according to the spatial structure of the underground scene to be analyzed; S1.2, using the data extraction tool Mike2Txt of the MIKE software, the flood dynamic information of each grid point in the underground scene model at each time step is obtained, including key information such as water depth, flow velocity, and flow direction.

4. The method for simulating personnel evacuation in a flood spreading situation in an underground scene according to claim 1, characterized in that: The process of S2 is as follows: S2.1, the underground scene is discretized based on cellular automata, and the spatial grid in the underground scene is consistent with the flood simulation scene; S2.2, use simulation software to construct structures representing pedestrians or obstacles in the space of the underground scene.

5. The method for simulating personnel evacuation in a flood spreading situation in an underground scene according to claim 1, characterized in that: Static field S i,j It is used to describe the distance from the cell to the exit. The field value increases along the exit direction and reaches the maximum at the exit. It is expressed as: Among them, (i, j) represents the coordinates of the cell in the space, (i e , j e ) represents the coordinates of the exit cell, (i l , j l ) represents the coordinates of any cell in space, d max is the maximum distance of any cell from the exit in the space, x,y∈[-1,1]; Represents the dimensionless static field value; max(S i+x,j+y ) is the maximum value of the static field in cell (i, j) and its eight adjacent cells.

6. The method for simulating personnel evacuation in a flood spreading situation for an underground scene according to claim 1, characterized in that: Water depth field H i,j It is used to describe the effect of water depth on pedestrian movement. The field value is designed to be inversely proportional to the water depth, expressed as: H i,j =H max -h i,j Among them, h i,j represents the water depth at cell (i, j), H max Represents the critical water depth for people to walk in water, Represents the dimensionless water depth field value; max(H i+x,j+y ) is the maximum value of the water depth field in cell (i, j) and its eight adjacent cells.

7. The method for simulating personnel evacuation in a flood spreading situation in an underground scene according to claim 1, characterized in that: The support field is used to describe the influence of the support on the movement of personnel. The value of the support field increases with the increase of water depth, which is expressed as: Among them, U' i,j To describe the distance from the support to the exit, (i U , j U ) represents the cell coordinates where the support is located, d Umax Represents the maximum distance between any cell in space and the support. represents the dimensionless support field value; max(U i+x,j+y ) is the maximum value of the support field in cell (i, j) and its eight adjacent cells.

8. The method for simulating personnel evacuation in a flood spreading situation in an underground scene according to claim 1, characterized in that: Velocity field F i,j It is used to describe the impact of flood velocity and direction on pedestrian movement, expressed as: in, represents the magnitude and direction of the flow velocity in the cell, is a unit vector, F i,j represents the projection of the flow velocity on the cell (i, j), represents the dimensionless velocity field, max(F i+x,j+y ) is the maximum value of the velocity field in cell (i, j) and its eight adjacent cells.

9. The method for simulating personnel evacuation in a flood spreading situation in an underground scene according to claim 1, characterized in that: The thresholds of flow velocity or water depth at different locations are used to judge whether pedestrians are unstable in waterlogging disasters, which can be expressed as: On the platform: (1)V f h≥1.2m 2 / s (2)V f ≥2.6m / s (3)h≥1.1m On the stairs: Where V f is the water velocity and h is the water depth.

10. A personnel evacuation simulation system for underground flood spreading situations, characterized in that: Used to implement a method for simulating personnel evacuation in a flood spreading situation for an underground scene as described in claim 1, the system includes a parameter definition module, a flood spreading module and a pedestrian position update module; The parameter definition module is used to build the underground scene model, establish the grid coordinate system of the underground scene model, and define the cell size after fine grid division, the time step length, the position occupied by pedestrians and obstacles in the subway grid coordinate system, and the pedestrian movement speed; The flood spread module is equipped with the MIKE21 two-dimensional hydrodynamic model, which is used to simulate the movement of water bodies in flood events and can generate real-time data on water depth, flow velocity and flow direction in the flooded area; The pedestrian position update module is used to quantify the impact of floods on pedestrian movement. It integrates the flood dynamic information provided by the flood spread module and considers the influencing factors of water depth, flow velocity and flow direction on the direction and speed of pedestrian movement.

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