Method for simulating process of mass sudden water inrush accidents in underground space and method for evaluating escape safety level

Abstract

The invention discloses an underground space mass water inrush accident process simulation method and an escape safety level evaluation method, and the method comprises the steps: building a three-dimensional model according to the building structure and equipment arrangement of an underground space; grid division is carried out on the three-dimensional model, and unit and node data needed by fluid dynamics simulation are generated and calculated; determining initial conditions and boundary conditions; establishing a multiphase flow model according to the initial condition and the boundary condition; inputting the unit and node data, the initial condition and the boundary condition into a multiphase flow model, and simulating the dynamic process of a large number of water inrush accidents in the underground space to obtain a simulation result; and determining emergency disposal measures according to the simulation result. By means of the scheme, the dynamic process analysis precision of a large number of sudden water inrush accidents in the underground space can be improved, and therefore the escape safety level of each area in the underground space can be scientifically and reasonably evaluated.

Description

Technical Field

[0001] The present invention relates to the technical field of public safety and disaster prevention and reduction, and particularly relates to a method for simulating the process of a large amount of sudden water inrush accidents in underground spaces and evaluating the escape safety level. Background Art

[0002] In extremely heavy rain and debris flow disaster events, underground spaces, such as underground factories, subway systems, underground garages, etc., due to their special geographical locations and building structure characteristics, are prone to accidents such as flood intrusion and high-pressure pipeline rupture and water inrush. Coupled with the significant internal space drop and complex building structures, it greatly increases the destructiveness of disasters and the difficulty of escape and rescue. In order to improve the prevention level of the water inlet risk in underground spaces and propose more targeted prevention and emergency measures, some scholars have tried to use empirical formulas to analytically calculate the submerged water depth and corresponding time in underground spaces. However, the analytical calculation formula simplifies the spatial pattern of underground spaces. Due to the large number of chambers in underground spaces, the connecting channels are intricate, and when facing fast water flow velocity, turbulent flow state, and diverse forms, the direct solution results of empirical formulas are difficult to accurately reflect the flow field characteristics during the water inlet process in underground spaces, and it is also difficult to give key information such as flow velocity, flow state, and water level rising speed, unable to meet the design requirements of emergency response. By means of computational fluid dynamics (CFD) simulation technology, it is possible to accurately simulate the flooding process of underground spaces under different water inflow conditions, thereby providing a scientific basis and technical support for key design links such as evacuation passage planning and emergency shelter setting. In addition, combined with the cellular automata method, the escape time of each area in the underground space can be estimated, thereby evaluating the escape safety level of each area in the underground space. Summary of the Invention

[0003] The present invention provides a method for simulating the process of a large amount of sudden water inrush accidents in underground spaces and a method for evaluating the escape safety level, so as to improve the analysis accuracy of the dynamic process of a large amount of sudden water inrush accidents in underground spaces and provide a method for evaluating the escape safety level of each area in the underground space.

[0004] To this end, the present invention provides the following technical solutions: A method for simulating the process of a large amount of sudden water inrush accidents in underground spaces, the method comprising: Constructing a three-dimensional model according to the building structure and equipment layout of the underground space; Performing mesh division on the three-dimensional model to obtain the cell and node data required for computational fluid dynamics simulation; Determining the initial conditions and boundary conditions; Establishing a multiphase flow model according to the initial conditions and boundary conditions, the multiphase flow model being used to calculate the data of the flooded factory building; Inputting the unit and node data, as well as the initial conditions and boundary conditions into the multiphase flow model, simulating the dynamic process of a large amount of sudden water inrush accident in the underground space, and obtaining simulation results; Emergency response measures are determined according to the simulation results, and the emergency response measures include emergency escape route planning.

[0005] Optionally, the method also includes: when constructing the three-dimensional model, ignoring fine structures to reduce the amount of calculation, simplifying the extraction of water flow space involved in the dynamic process of water inflow disasters, and for solid areas that do not participate in fluid numerical simulation, only retaining the wall surface of the solid area as the fluid boundary.

[0006] Optionally, meshing the three-dimensional model includes any one or more of the following: Use structured meshing to divide regular geometry to improve computational efficiency; Unstructured grids are used to divide complex structures to improve adaptability to complex structures; Densify the mesh in key areas to capture eddies and turbulence; The final grid division method is determined based on the calculation accuracy and time cost of grid division at each granularity.

[0007] Optionally, the key area includes any one or more of the following areas: an entrance, a narrow passage, and a staircase.

[0008] Optionally, determining the initial conditions and boundary conditions includes: Large-scale sudden water inrush accidents in underground spaces are divided into two categories: one is that flood water intrudes from the entrance and exit holes of the underground space, and the corresponding hole is set as the open channel inlet boundary condition, and the water depth is used to represent the magnitude of the intruding flood; the other is that sudden water inrush occurs when the high-pressure pipeline in the underground space ruptures, and the corresponding rupture is set as the pressure inlet boundary condition, and the pressure value is used to represent the intensity of the water inrush; The remaining openings of the underground space are set as pressure outlet boundaries with atmospheric pressure; the remaining walls adopt no-slip wall boundary conditions.

[0009] Optionally, establishing a multiphase flow model includes: Determine the numerical calculation method of three-dimensional fluid mechanics; A multiphase flow model is established according to the three-dimensional fluid mechanics numerical calculation method.

[0010] Optionally, the method further includes: analyzing the impact of the water intrusion disaster based on the simulation results.

[0011] A method for evaluating the escape safety level of each area in an underground space in a large amount of sudden water inrush accident, the method comprising: Divide the underground space into uniform cells and allocate personnel in the cells; Determine the attribute set of the cell where the escape personnel are located; Determine the escape movement direction of the personnel in the cell according to the emergency escape route planning determined by the underground space large-scale sudden water inrush accident process simulation method, and determine the movement speed according to the attribute set of the cell; Determine the total evacuation time of the personnel according to the escape movement direction and movement speed of the personnel in the cell; Determine the escape safety level according to the total evacuation time of the personnel, and obtain the escape safety levels of each area of the underground space.

[0012] Optionally, the distribution of the personnel in the cell includes: randomly or distributing the personnel in the cell according to a specific distribution.

[0013] Optionally, the attribute set of the cell includes: the water depth of the cell, the flow velocity, and the dot product of the water flow direction and the human movement direction.

[0014] Optionally, the determination of the escape movement direction and movement speed of the personnel in the cell includes: Determine the escape movement direction of the personnel in the cell according to the pre-determined emergency escape route planning; Determine the movement speed of the personnel in the cell according to the cell attributes.

[0015] Optionally, the movement speeds of the personnel in the same cell are the same.

[0016] Optionally, the total evacuation time includes: a preparation time and a movement time; the preparation time is the time from the occurrence of the accident to the start of the personnel's movement; the movement time is the time for the personnel to reach the designated safe area from the initial area.

[0017] Optionally, the method further includes: determining the escape success probability according to the escape uncertainty; Correspondingly, the determination of the escape safety level according to the total evacuation time of the personnel includes: determining the escape safety level by comprehensively considering the total evacuation time and the escape success probability.

[0018] The method for simulating the process of a large amount of sudden water inrush accidents in underground spaces and evaluating the escape safety level provided by the present invention, based on the overall layout of the underground space building structure and equipment facilities, uses a multiphase flow model to construct a numerical simulation model for the dynamic process of a large amount of sudden water inrush accidents in underground spaces. By using this model, it is possible to improve the accuracy of the analysis of the dynamic process of a large amount of sudden water inrush accidents in underground spaces, and thus contribute to the planning of emergency escape routes through dynamic process simulation, propose targeted preventive and emergency measures, support the compilation of emergency plans, and improve the safety and emergency management level of underground public spaces. In combination with the cellular automata method, it is also possible to estimate the escape time of each area in the underground space, so as to evaluate the escape safety level of each area in the underground space. Moreover, this solution is simple to use. Users do not need to understand the internal implementation process of the solution, nor do they need to have a professional knowledge background in relevant CFD numerical calculations. Based on the pre-constructed multiphase flow model and escape safety level evaluation model, according to the process prompts and different water inflow situations in the underground space, by setting the initial conditions and boundary conditions, the numerical simulation results of the dynamic process of water inflow in the underground space, emergency escape routes, and the escape safety level of each area can be automatically obtained, greatly improving the analysis efficiency and reducing the user's usage threshold. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the embodiments. Obviously, the drawings described below are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0020] Figure 1 is a flowchart of a method for simulating the process of a large amount of sudden water inrush accidents in an underground space according to an embodiment of the present invention; Figure 2 is a schematic diagram of a three-dimensional model of an underground space established in an embodiment of the present invention; Figure 3 is a schematic diagram of the mesh division effect of the three-dimensional model of the underground space; Figure 4 is a schematic diagram of the measured point water head change curves in three different large amount of sudden water inrush accidents in the underground space calculated by using the multiphase flow model established in an embodiment of the present invention; Figure 5 is Figure 4 the schematic diagram of the stable water level in the two different underground space water inflow accidents shown; Figure 6 is Figure 4 the schematic diagram of the flow velocity distribution in the corridor layer when the water inrush floods the corridor layer in the two different underground space water inflow accidents shown; Figure 7 is Figure 4Schematic diagram of the flow velocity distribution in the middle layer when the water surges to the middle layer in two different underground space water inlet accidents shown; Figure 8 It is a flowchart of a method for evaluating the escape safety level of each area in the case of a large amount of sudden water gushing in the underground space in the embodiment of the present invention; Figure 9 It is a schematic diagram of the cell division and numbering of the middle layer in the underground space in the embodiment of the present invention; Figure 10 It is a schematic diagram of the calculation rule of the personnel movement speed based on the cellular automaton in one layer of the underground space. Detailed implementation manners

[0021] The following will describe the detailed implementation manners of the present invention in conjunction with the accompanying drawings. It should be understood that the detailed implementation manners described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0022] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] Due to the many problems existing in the existing solution of directly analyzing the flooding process of the underground space by using the direct solution results of empirical formulas, it cannot meet the requirements of emergency response design. In addition, with the continuous development of computing technology, computational fluid dynamics has become more and more mature in dealing with unsteady problems where the flow field changes rapidly with time, and can perform numerical simulations of fluid flow conditions based on the high-precision three-dimensional model of the physical object, and obtain the characteristic information of the flow field at each moment, thereby effectively making up for the defects of empirical formulas. For this reason, the embodiments of the present invention provide a method for simulating the process of a large amount of sudden water gushing in the underground space and evaluating the escape safety level, which, based on the overall layout of the underground space, uses fluid mechanics to construct a multiphase flow model for numerical calculation of the dynamic process of a large amount of sudden water gushing in the underground space, performs high-precision simulation of the dynamic process of a large amount of sudden water gushing in the underground space, and realizes reasonable emergency evacuation route planning. And on this basis, combined with the cellular automaton method, the escape time of each area in the underground space is estimated, so as to evaluate the escape safety level of each area in the underground space.

[0024] As Figure 1 shown, it is a flowchart of a method for simulating the process of a large amount of sudden water gushing in the underground space in the embodiment of the present invention, including the following steps: Step 101, construct a three-dimensional model according to the building structure and equipment layout of the underground space.

[0025] The three-dimensional model needs to construct important flow spaces such as the main power building, the main transformer tunnel and the connecting passages between the caverns.

[0026] When constructing the three-dimensional model, small structures (such as vents, pipes, etc.) can be ignored to reduce the amount of calculation, simplify the extraction of the water flow space involved in the dynamic process of water inflow disasters, and for solid areas that do not participate in fluid numerical simulation, only the wall surface of the solid area is retained as the fluid boundary.

[0027] like Figure 2 , which is a schematic diagram of a three-dimensional model of an underground space established in an embodiment of the present invention.

[0028] The three-dimensional model includes structures such as the main plant building 1, the main transformer tunnel 2, the busbar shaft 3, the ventilation and safety tunnel 4, the plant access tunnel 5, and the busbar corridor 6.

[0029] It should be noted that underground space usually also includes structures such as drainage corridors and various connecting passages. Figure 2 They are not shown one by one.

[0030] Step 102, meshing the three-dimensional model to obtain unit and node data required for computational fluid dynamics simulation.

[0031] Specifically, the three-dimensional model is network-divided to obtain mesh division diagrams of different regions, and then the unit and node data required for computational fluid dynamics simulation are obtained based on the mesh division diagrams.

[0032] The meshing diagram is a grid structure that discretizes continuous space into a finite number of units or nodes during numerical simulation and calculation. This process divides complex geometric shapes into a series of simple geometric units for numerical calculation and analysis.

[0033] In some embodiments, structured meshes can be used to divide regular geometry to improve computational efficiency, and unstructured meshes can be used to divide complex structures to improve adaptability to complex structures. In addition, meshes can be encrypted in key areas such as entrances, narrow passages, and stairs to capture eddies and turbulence.

[0034] In some embodiments, the three-dimensional model may be meshed in a variety of different granularities; the final meshing method is determined based on the calculation accuracy and time cost of the meshing of each granularity.

[0035] For example, in order to find a balance between calculation accuracy and calculation speed, three grid division schemes with a total grid number of 2 million, 3 million, and 4 million are selected. The three grid division schemes have a slightly local impact on the results, but do not change the overall trend. The difference in the initial flooding flow rate calculated in Scheme 2 and Scheme 3 is less than 2%. The initial flooding flow rate refers to the relative difference between the initial flow rates of the water inrush points. The acceptable relative error default in engineering is 5%. Since the calculation accuracies of Scheme 2 and Scheme 3 are comparable, and the grid of Scheme 3 is significantly more, more computing resources are required. Therefore, considering both calculation accuracy and time cost comprehensively, Scheme 2 is selected as the final grid division method, and its total grid number is 3 million.

[0036] Figure 3 The schematic diagram showing the grid division effect corresponding to the three-dimensional model is shown.

[0037] Step 103, determine the initial conditions and boundary conditions.

[0038] The initial conditions refer to the initial values of the boundary conditions or the initial values of the variables for which the definite solution is obtained through iterative calculation.

[0039] In order to improve the accuracy of the simulation results, a large number of sudden water inrush accidents in the underground space can be divided into two categories: one is that the flood invades from the inlet and outlet openings of the underground space, and the corresponding openings are set as the open channel inlet boundary conditions, and the water depth is used to characterize the magnitude of the invading flood volume; the other is that the sudden water inrush is caused by the rupture of the high-pressure pipeline inside the underground space, and the corresponding rupture is set as the pressure inlet boundary condition, and the pressure value is used to characterize the water inrush intensity. The remaining openings of the underground space are set as the pressure outlet boundaries, and the pressure value is the atmospheric pressure; the remaining walls adopt the no-slip wall boundary conditions.

[0040] For example, in one example, the initial conditions and boundary conditions of a large number of sudden water inrush accidents in the underground space in the three-dimensional numerical simulation are shown in Table 1 below.

[0041] Table 1

[0042] Step 104, establish a multiphase flow model according to the initial conditions and boundary conditions, and the multiphase flow model is used to calculate the data of the flooded workshop.

[0043] Specifically, the three-dimensional hydrodynamics numerical calculation method needs to be determined first. For example, in a non-limiting embodiment, the calculation methods are mainly divided into the following two types: (1)Generally, the VOF (Volume of Fluid) model is preferably adopted. This model is a numerical method for simulating multiphase flows. It can model two or more immiscible fluids by solving a set of momentum equations and tracking the volume fraction of each fluid throughout the computational domain, and has outstanding advantages in capturing the interfacial boundaries between phases. The VOF model tracks the fluid interfaces by solving the volume fractions of different fluids in each computational cell, thereby simulating the interfacial positions of two or more immiscible fluids.

[0044] (2)If there is a situation where the water flow contains a large amount of sediment, the Mixture model can be used. This model is a simplified Eulerian multiphase flow model that describes the overall flow behavior by solving the mixture momentum equation and uses the relative velocity to characterize the motion characteristics of the dispersed phase, thus can be used to simulate multiphase flows with different velocities for each phase.

[0045] Then, a multiphase flow model is established according to the three-dimensional hydrodynamic numerical calculation method.

[0046] Step 105: Input the units, the node data, as well as the initial conditions and boundary conditions into the multiphase flow model to simulate the dynamic process of a large amount of sudden water inrush accidents in the underground space, and obtain the simulation results.

[0047] The simulation results are the flow field data during the dynamic process of a large amount of sudden water inrush accidents in the underground space, mainly including: the changes in water depth, flow rate, and flow velocity of each layer in the underground space over time, the moment when the water level reaches key positions, the time history of the water level submerging key channels, etc., which can be obtained by iteratively calculating the fluid continuity equation, motion equation, and multiphase flow equation on the grid.

[0048] Using the multiphase flow model, the flow field data during the dynamic process of a large amount of sudden water inrush accidents in the underground space can be calculated conveniently, efficiently, and accurately, improving the analysis accuracy of the dynamic process of water inflow into the underground space.

[0049] Step 106: Determine the emergency response measures according to the simulation results. For example, determine the emergency evacuation route planning according to the simulation results.

[0050] For example, in a specific application example, using the multiphase flow model established in the embodiment of the present invention, the measured point water head change curves under two different (hereinafter referred to as: Example 1, Example 2) underground space water inflow accidents calculated, and the water inflow time node data of each layer of the main plant building and the main transformer cave are respectively as Figure 4 shown in (a) and (b) below. Among them, Figure 4In (a) and (b), they respectively correspond to Example 1 and Example 2. The head change curve is drawn based on the head of the measuring point at the bottom layer of the corridor. The measuring point is located at the bottom plate of the corridor layer at an elevation of 1965.1 m. The red and blue punctuation marks indicate the water inlet time points of each layer of the main powerhouse and the main transformer cavern.

[0051] Under different water inlet conditions, the water inlet times of each layer of the main powerhouse and the main transformer cavern are shown in Table 2 below.

[0052] Table 2

[0053] The stable water levels in the above two different underground space water inlet accidents are as Figure 5 shown, Figure 5 In (a) and (b), they respectively correspond to the stable water levels of Example 1 and Example 2 in Table 2.

[0054] It can be seen from Figure 5 that in both examples, the water level after stabilization will submerge the access tunnel to the power plant, the generator floor of the main powerhouse, and the main transformer floor of the main transformer cavern.

[0055] Under the above two different underground space water inlet accidents, when the water gushing from the water gushing accident reaches the corridor layer, the velocity distribution in the corridor layer is as Figure 6 shown, and when the water gushing reaches the middle layer, the velocity distribution in the middle layer is as Figure 7 shown.

[0056] It can be seen from Figure 6 that in Example 1, the water surface velocity in most areas at the connection end of the access tunnel to the power plant and the powerhouse is greater than 1 m / s. In Example 2 and Working Condition 3, the initial water surface velocity has exceeded 3 m / s, and it will be relatively difficult for personnel to wade through the access tunnel to the power plant.

[0057] Figure 7 In the three working conditions shown, the upper and lower ends on the left are the positions of the access doors. The initial water flow in the busbar channel flows from the main powerhouse to the main transformer cavern. There are strong vortices in the channel, and the high-speed velocity area is located on the left side of the channel near the door. In Example 1 and Example 2, the water flow velocity at the access door is greater than 1 m / s. In Example 3, since the water flows from the access tunnel to the main powerhouse and the main transformer cavern at similar times, when the busbar channel is flooded, its upper structure is already filled with water. Therefore, personnel should not wade through the busbar channel during the underground space water inlet accident.

[0058] From the above calculation results, it can be seen that at the initial stage of the underground space water inlet, personnel should not move between the main powerhouse and the main transformer cavern through the busbar channel. They should reduce the horizontal movement at the initial stage of flooding and move upward to the safe area as soon as possible, and then escape along the safe passage.

[0059] Based on the above calculation results, the escape route design and escape time calculation can be carried out. Specifically as follows: At the first moment of a large-scale sudden water inrush accident in the underground space, personnel should move upward to the upper layer as soon as possible and should not stay at the bottom layer. From the distribution of the water inflow velocity in the access tunnel and the horizontal busbar tunnel, it can be seen that personnel should not make horizontal displacements, nor should they move to different cavities at a relatively long distance.

[0060] Therefore, the escape routes of personnel in the main powerhouse during a large-scale sudden water inrush accident in the underground space are planned as shown in Table 3, that is: Gallery Floor 1965.1 m → Turbine Floor 1980 m → Intermediate Floor 1986 m → Generator Floor 1992 m → Roof of the Auxiliary Powerhouse in the Erection Bay → Ventilation and Safety Tunnel. It is recommended that the personnel in the main powerhouse move upward to the upper layer as soon as possible and then escape through the ventilation and safety tunnel on the roof of the auxiliary powerhouse in the erection bay. The top floor of the First Auxiliary Powerhouse where the central control room is located is connected to the ventilation and safety tunnel through the upper drainage tunnel. The personnel in the central control room can move to the ventilation and safety tunnel through the upper drainage tunnel from the top floor of the First Auxiliary Powerhouse.

[0061] Table 3

[0062] From the water inlet time of each working condition, it can be seen that the escape time left for the personnel at the bottom layer of the main powerhouse is extremely short. In the water inlet working condition of the access tunnel, the water inlet time of each floor of the main powerhouse except the top floor is less than 4 minutes, which puts higher requirements on the early warning system in the underground space.

[0063] The escape routes of personnel on each floor of the main transformer cavity are shown in Table 4, that is: Cable Floor 1986 m → Main Transformer Floor 1992 m → Ventilation Floor 2007 m → Busbar Shaft. It is recommended that the personnel in the main transformer cavity escape through the busbar shaft near the middle of the main transformer cavity.

[0064] Table 4

[0065] Compared with the main powerhouse, the overall elevation difference of the main transformer cavity is smaller, and the personnel in the main transformer cavity have more escape time through the busbar shaft.

[0066] It can be seen that by using the method for constructing a large-scale sudden water inrush accident scenario in the underground space provided by the embodiment of the present invention, key information such as the change process of the water inrush flow rate, the change process of the water level in the powerhouse, the flow velocity distribution in the powerhouse, and the flooding time of each floor in the powerhouse during the water inlet process of the underground space can be analyzed in cases such as high-pressure water passing structures and water inlet in the access tunnel. This method can efficiently and accurately analyze the dynamic process of water inlet in the underground space and support the preparation of relevant emergency plans.

[0067] In some embodiments, the impact of the water inlet disaster can also be analyzed according to the simulation results.

[0068] Correspondingly, the embodiment of the present invention also provides a method for evaluating the escape safety level of each area in a large-scale sudden water inrush accident in the underground space, such asFigure 8 As shown in the figure, it is a flowchart of a method for evaluating the escape safety level of each area in the case of a large amount of sudden water inrush in the underground space of an embodiment of the present invention, including the following steps: Step 801: Divide the underground space into uniform cells and allocate the people in the cells.

[0069] The cell division is to divide the evacuation space into uniform grids, that is, cells, by introducing the idea of cellular automata (CA). The cellular automata is a grid dynamics model with discrete time, space, and state, and local spatial interaction and time causality, and has the ability to simulate the spatio-temporal evolution process of complex systems.

[0070] In some embodiments, the people in the cells can be placed randomly or according to a specific distribution.

[0071] As Figure 9 shown in the figure, it is a schematic diagram of cell division and numbering of the middle layer in the underground space of an embodiment of the present invention. Among them Figure 9 (a) in the figure is the middle layer structure, Figure 9 and (b) in the figure is the cell numbering corresponding to the middle layer division. The middle layer is divided into 100 cells as a whole, and the non-flow area is represented by "×".

[0072] Step 802: Determine the attribute set of the cell where the escape personnel are located.

[0073] To simplify the calculation process, a suitable time step is selected in this example for step-by-step calculation. When calculating to a certain moment t, the number of steps that have been calculated is n. The attribute set of the cell includes the water depth v, the flow velocity magnitude u, the dot product of the water flow direction and the human movement direction and other attributes, which can be expressed as: where represents the current position of the escape personnel, and represents the number of steps calculated. To simplify the calculation process, a suitable time step n can be selected for step-by-step calculation. When calculating to a certain moment

[0074] t, the number of steps that have been calculated is

[0075] The emergency escape route plan can be in accordance with the above Figure 1The emergency escape route plan obtained by the simulation method for a large number of sudden water inrush accidents in underground spaces using the shown process.

[0076] In some embodiments, the escape movement direction of the people in each cell can be determined according to the pre-determined emergency escape route plan. To reduce the computational complexity, when determining the movement speed, individual differences such as gender, age, familiarity, willingness to escape, panic index, physical strength value, etc. of the people may not be considered, and the people in the same cell have the same movement speed.

[0077] In the embodiments of the present invention, the movement speed of people is only related to the cell attributes, and the relevant function can be obtained based on experience and tests.

[0078] In the calculation of the movement speed of people, first, the flow field situation of the underground space is determined according to the CFD calculation results, and the movement direction is determined according to the emergency escape route plan results; then, a calculation local area is delimited for the area where the escape people are located, and the calculation is performed according to the movement speed calculation rules for the local area.

[0079] As Figure 10 shown, it is a schematic diagram of the calculation rules for the movement speed of people based on cellular automata in one layer of the underground space.

[0080] Among them, the yellow marked area is the cell where the current person is located x , the blue ripples represent the attribute set of the cell where the current person is located , the blue arrow represents the movement direction of the people determined according to the CDF calculation results, and the black arrow represents the movement speed of the current person.

[0081] Assume that the global flow field and the local area movement direction are as Figure 10 shown in (a) below, and the calculation process is as follows: The first step is to determine the initial state, as Figure 10 shown in (b) below.

[0082] Only the flow field state of the area where the people are located is required, and the attribute set of each cell described in step 802 can be obtained according to the CFD calculation results .

[0083] The second step is to determine the movement speed of the people according to the flow field situation of the area where the people are located, as Figure 10 shown in (c) below.

[0084] The movement speed of the people at the current moment and the movement speed at the previous moment , the attribute set are related as: ; In the formula, is the water depth resistance coefficient (the velocity decay coefficient related to water depth); is the water flow resistance coefficient (dimensionless, reflecting the hindrance of water flow to movement).

[0085] In the third step, adjust the speed and route, as shown in (d) of Figure 10 .

[0086] Considering that the moving speed will slow down when turning or climbing stairs from the current position to the next position, the moving speed needs to be adjusted to: ; where is the distance from the current position to the position that needs to turn, is the time step. Combining with the moving direction of the person, the displacement of the person can be finally determined.

[0087] In the fourth step, update the position, as shown in (e) of Figure 10 .

[0088] According to the current coordinates and the finally determined displacement , obtain the new coordinates : .

[0089] In the fifth step, update the flow field, as shown in (f) of Figure 10 .

[0090] According to the time step and the updated position of the person, combined with the CFD calculation results, update the flow field: .

[0091] Step 804: Determine the total evacuation time of the person according to the escape movement direction and moving speed of the person in the cell.

[0092] The total evacuation time includes the preparation time and the moving time, that is:

[0093] where the preparation time is the time from the occurrence of the accident to the start of the person's movement, including the detection time, the alarm time, the recognition time and the reaction time, that is:

[0094] where the moving time is the time for the person to reach the designated safe area from the initial area.

[0095] Step 805: Determine the escape safety level according to the total evacuation time of the person, and obtain the escape safety levels of each area in the underground space.

[0096] It should be noted that if the flow field conditions in the area where the personnel are located are harsh, such as the water depth is too deep or the flow velocity is too fast, and it does not support the escape of personnel, the moving speed of the personnel can be set to zero and the escape time can be set to infinity.

[0097] The escape safety level is related to the total evacuation time RSET (Required Safe Egress Time). The longer the total evacuation time, the higher the escape safety level. By calculating the total evacuation time RSET of the personnel in each area of the middle layer, the escape safety level of each area of the underground space can be determined.

[0098] Considering the uncertainty of the escape individuals and the environment, for different individuals and environments, the probability of successful escape will also be different. Therefore, in some embodiments, the probability of successful escape can also be determined through uncertainty analysis. The higher the probability of successful escape, the higher the escape safety level. Correspondingly, the escape safety level can be determined by comprehensively considering the total evacuation time and the probability of successful escape. The escape safety level can be calculated by setting a function including these two parameters of the total evacuation time and the probability of successful escape, or can be determined by setting a grading standard based on these two parameters. The embodiments of the present invention do not make any limitations in this regard.

[0099] The specific function formula and the grading standard of the escape level can be determined according to the following principles: the longer the total evacuation time, the higher the escape safety level; the higher the probability of successful escape, the higher the escape safety level.

[0100] For example, the time ASET (Available Safe Egress Time) from the occurrence of danger to the environment reaching the non-survivable condition can be obtained from the CDF calculation result, such as when the flood water depth exceeds 0.8m and the flow velocity exceeds 2m / s, etc.

[0101] Considering the uncertainty, the probability of success is simulated through Monte Carlo. It is considered that ASET is affected by the spread speed of the water situation, and RSET is affected by factors such as personnel reaction, physical strength, and emotion, and both show a normal distribution. Safety level = P(ASET > RSET). For example: If P is greater than 99%, the safety level is level one; If P is greater than 99% and less than 95%, the safety level is level two; If P is less than 95%, the safety level is level three.

[0102] Assume that the standard deviation of the normal distribution is 0.05×RSET, and some typical areas are selected for display, as shown in Table 5.

[0103] Table 5

[0104] The method for constructing the scenario of a large amount of sudden water inrush accidents in underground spaces and the method for evaluating the escape safety level provided by the embodiments of the present invention, according to the overall layout of the underground space, adopt the finite volume method. By constructing a three-dimensional model of the underground space, key information such as the change process of the elevation of the inundation water level and the distribution of water surface velocities in the underground space are analyzed under the conditions of high-pressure pipeline rupture and water inrush, external flood inflow, etc. Using the solution of the present invention, it is possible to conveniently, efficiently and accurately calculate the data of the underground space based on different water inflow conditions, realize the numerical simulation and scenario deduction of the inundation dynamic process of the underground space, so as to provide a scientific basis and technical support for key design links such as evacuation passage planning and the setting of emergency shelters. In addition, combined with the cellular automata method, the escape time of each area of the underground space can be estimated, so as to evaluate the escape safety level of each area of the underground space. Provide accurate data support for the compilation of relevant emergency plans.

[0105] The embodiments of the present invention have been introduced in detail above. Specific implementation manners have been used in this article to elaborate on the present invention. The description of the above embodiments is only used to help understand the method of the present invention. They are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention. The content of this specification should not be construed as a limitation to the present invention. Therefore, any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A simulation method for the process of a large amount of sudden water inrush accidents in underground spaces, characterized in that, The method includes: Construct a three-dimensional model according to the architectural structure and equipment layout of the underground space; Perform mesh division on the three-dimensional model to obtain the element and node data required for computational fluid dynamics simulation; Determine the initial conditions and boundary conditions: Classify the large-scale sudden water inrush accidents in the underground space into two categories: One category is that flood water invades from the inlet and outlet openings of the underground space, and the corresponding openings are set as open-channel inlet boundary conditions, with the water depth representing the magnitude of the invading flood water volume; The other category is that a sudden water inrush occurs due to the rupture of a high-pressure pipeline inside the underground space, and the corresponding rupture opening is set as a pressure inlet boundary condition, with the pressure value representing the water inrush intensity; The remaining openings of the underground space are set as pressure outlets, and the pressure value is the atmospheric pressure; The remaining walls adopt no-slip wall boundary conditions; Establish a multiphase flow model according to the initial conditions and boundary conditions, and the multiphase flow model is used to calculate the data of the flooded plant; Input the element and node data, as well as the initial conditions and boundary conditions into the multiphase flow model, simulate the dynamic process of the large-scale sudden water inrush accident in the underground space, and obtain the simulation results; Determine the emergency response measures according to the simulation results, and the emergency response measures include emergency escape route planning.

2. The method for simulating the process of a large amount of sudden water inrush accident in underground space according to claim 1, characterized in that, The method further includes: When constructing the three-dimensional model, ignore small structures to reduce the computational amount, simplify the extraction of the water flow space involved in the dynamic process of the water inrush disaster, and for the solid regions that do not participate in the fluid numerical simulation, only retain the walls of the solid regions as fluid boundaries.

3. The simulation method for the process of large-scale sudden water inrush accidents in underground spaces according to claim 1, characterized in that, The mesh division of the three-dimensional model includes any one or more of the following: Adopt structured grid meshing for regular geometries to improve the computational efficiency; Adopt unstructured grid meshing for complex structures to improve the adaptability to complex structures; Dense the grid in key regions to capture vortices and turbulence; The key regions include any one or more of the following regions: entrances, narrow channels, stairs; Determine the final mesh division method according to the computational accuracy and time cost of the mesh division of each granularity.

4. The method for simulating the process of a large amount of sudden water inrush accident in underground space according to claim 1, characterized in that, The establishment of the multiphase flow model includes: Determine the three-dimensional fluid mechanics numerical calculation method; Establish a multiphase flow model according to the three-dimensional fluid mechanics numerical calculation method.

5. The method for simulating the process of a large amount of sudden water inrush accident in underground space according to any one of claims 1 to 4, characterized in that, The method further includes: Analyze the impact of the water inrush disaster according to the simulation results.

6. A method for evaluating the escape safety level of each area in a large-scale sudden water inrush accident in underground space, characterized in that, The method includes: Divide the underground space into uniform cells, and randomly or according to a specific distribution allocate the people in the cells; Determine the attribute set of the cells where the escaping people are located; Determine the escape movement direction of the people in the cells according to the emergency escape route planning determined by the method for simulating the process of large-scale sudden water inrush accidents in the underground space according to any one of claims 1 to 5, and determine the movement speed according to the attribute set of the cells; Determine the total evacuation time of the people according to the escape movement direction and movement speed of the people in the cells; Determine the escape safety level according to the total evacuation time of the people, and obtain the escape safety levels of each region of the underground space.

7. The method for evaluating the escape safety level of each area in the accident of a large amount of sudden water inrush in underground space according to claim 6, characterized in that, The attribute set of the cells includes: the water depth of the cells, the flow velocity, and the dot product of the water flow direction and the human movement direction.

8. The method for evaluating the escape safety level of each area in the accident of a large amount of sudden water gushing in underground space according to claim 6, characterized in that, The determination of the escape movement direction and movement speed of the people in the cells includes: Determine the escape movement direction of the people in the cell according to the pre-determined emergency escape route plan; Determine the movement speed of the people in the cell according to the cell attributes; the movement speeds of the people in the same cell are the same.

9. The method for evaluating the escape safety level of each area in the accident of a large amount of sudden water inrush in underground space according to claim 6, characterized in that, The total evacuation time includes: a preparation time and a movement time; the preparation time is the time from the occurrence of the accident to the start of the movement of the people; the movement time is the time for the people to reach the designated safe area from the initial area.

10. The method for evaluating the escape safety level of each area in the accident of a large amount of sudden water gushing in underground space according to any one of claims 6 to 9, characterized in that, The method further includes: Determine the escape success probability according to the escape uncertainty; The determining the escape safety level according to the total evacuation time of the people includes: Comprehensively determine the escape safety level based on the total evacuation time and the escape success probability.

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