A layered simulation method for surface structures in communities

Abstract

The present invention provides a layered simulation method for surface structures in a community, including obtaining building information, and further comprising the following steps: using a hydrological response unit to simulate the flow generation process of the building roof; and using a two-dimensional surface model to simulate the flow confluence process of the building itself. The layered simulation method for surface structures in a community proposed by the present invention can not only simulate the roof water runoff process, but also simulate the surface flooding process of the building.

Description

Technical Field

[0001] The invention relates to the technical field of surface runoff calculation, and in particular to a layered simulation method for surface structures in a community. Background Art

[0002] With the in-depth and refined research on urban flood disasters, more and more studies have shown that urban buildings can have an important impact on the flood process. Buildings have a water-blocking effect and change the flow path of surface runoff. In the process of urban rainstorm floods, the surface water flow caused by rainfall belongs to thin-layer water flow. The elevation of the transition point of buildings in the urban environment changes suddenly, and the water flow state is complex. There are currently four methods for dealing with buildings, namely the solid wall boundary method, the building elevation method, the increased roughness method, and the area correction rate method. Among them, when the solid wall boundary method is used to simulate the rainfall runoff process of buildings, the net rain on the roof of the building is not included in the numerical simulation calculation. It is necessary to artificially increase the rainfall intensity in other areas and calculate the rainfall falling on the roof of the building. This method artificially changes the rainfall process, and the rationality of the calculation method needs further analysis. When the building area correction rate method is used to simulate the rainfall runoff process of buildings, in the grid with a high proportion of building area, the rainfall is evenly distributed to the non-building area of ​​the grid unit. In the process, extremely high water depth will be generated in the calculation unit, which is easy to cause instability in numerical calculation. Under heavy rainfall conditions, although the building elevation method is the most suitable method for urban flood simulation among various building simulation methods, this method also has its shortcomings. The shortcomings are manifested in the following aspects:

[0003] (1) Existing methods can only simulate the water-blocking effect of surface structures, without considering the runoff generation and convergence function of the building roof, nor the function of the rainwater collection system on the roof.

[0004] (2) Buildings have the function of storing water and may become flooded objects. Existing methods cannot simulate their flooding process.

[0005] (3) It is difficult to obtain the elevation of the building roof, so the building roof is also simulated using a fine grid, which is a solution with a high computational cost.

[0006] The invention patent application with application number CN 114330152 A discloses a method for calculating surface runoff based on smooth particle fluid dynamics, including the following steps: initializing calculation conditions, using bottom particles to describe surface information, and using fluid particles to describe surface runoff; calculating acceleration according to the velocity and position of fluid particles at the current moment; calculating the velocity and position of the particle at the next moment according to the acceleration and position of the fluid particle; calculating the density and smooth length of the particle after moving to the new position; calculating the mass of the fluid particle according to the amount of rainfall and infiltration water, and performing momentum correction on the fluid particle; adding fluid particles in the initial state to the upstream area without particle coverage; calculating each time step and outputting the calculation results of surface runoff. The disadvantage of this method is that it cannot reflect the actual runoff process of the building.

[0007] The invention patent application with application number CN 110532641 A discloses a surface grid layered modeling method and system, wherein the method includes obtaining basic modeling data, and also includes the following steps: dividing the surface structure into several layers of grids; performing rainfall runoff calculation on the top grid; performing runoff calculation on each layer of surface grids; and generating a complex multi-layer structure runoff process model. The disadvantage of this method is that it is difficult to obtain the elevation of the building roof, and the building roof is also simulated using a refined grid, which is a solution with a high computational cost. In addition, the roof often has a complex drainage pipe system, and the topological relationship between the upper and lower layers modeled by this method is complex. Summary of the invention

[0008] In order to solve the above technical problems, the present invention proposes a layered simulation method for surface structures in a community, which can not only simulate the roof water runoff process, but also simulate the surface flooding process of buildings.

[0009] The purpose of the present invention is to provide a method for simulating layered surface structures in a community, comprising obtaining building information and further comprising the following steps:

[0010] Step 1: Use the hydrological response unit to simulate the runoff process on the roof of the building;

[0011] Step 2: Use a 2D surface model to simulate the flow process of the building itself.

[0012] Preferably, the building information includes building roof type and building floor information.

[0013] In any of the above solutions, it is preferred that the building roof types are generalized into two types, permeable roofs and impermeable roofs.

[0014] In any of the above solutions, preferably, the building floor information includes the building height and the number of building floors.

[0015] In any of the above schemes, preferably, step 1 includes calculating the runoff coefficient method for the flow generation process on the roof, and the formula is:

[0016] R=α×P

[0017] Among them, R is the runoff depth of the roof, α is the runoff coefficient, and P is the average rainfall depth in the corresponding period.

[0018] In any of the above schemes, preferably, the runoff coefficient α of the impermeable roof is 1.00, and the runoff coefficient α of the permeable roof is in the range of 0.30-0.40.

[0019] In any of the above solutions, preferably, step 2 includes determining a connection mode of the building drainage system and simulating a confluence process according to the connection mode.

[0020] In any of the above solutions, it is preferred that the connection method includes a connection method for high-rise buildings and multi-story buildings, and a connection method for low-rise buildings.

[0021] In any of the above schemes, it is preferred that the high-rise building refers to a residential building with a height greater than 27 meters and other non-single-story civil buildings with a height greater than 24 meters.

[0022] In any of the above schemes, preferably, the multi-storey building refers to a building that satisfies 10 meters < multi-storey building height < 24 meters and 3 floors < number of building floors < 7 floors.

[0023] In any of the above schemes, preferably, the low-rise building refers to a building with a building height of less than or equal to 10 meters and a building number of floors of less than or equal to 3.

[0024] In any of the above schemes, preferably, step 2 also includes establishing coupling relationships between the hydrological response unit and the surface grid unit and the pipe network node unit respectively according to the actual position of the downpipe for the high-rise building and the multi-story building.

[0025] In any of the above solutions, preferably, the runoff calculation steps for the high-rise building and the multi-story building are as follows:

[0026] Step 201: The hydrological response unit calculates the runoff depth using the runoff coefficient method;

[0027] Step 202: multiplying the runoff depth by the area of ​​the hydrological response unit to obtain the runoff volume;

[0028] Step 203: evenly distribute the runoff to M surface grids and pipe network nodes coupled thereto, where M is a positive integer greater than or equal to 1.

[0029] In any of the above solutions, preferably, the runoff calculation steps for the low-rise building are as follows:

[0030] Step 211: The hydrological response unit calculates the runoff depth using the runoff coefficient method;

[0031] Step 212: Calculate the overflow of the roof using the weir flow formula;

[0032] Step 213: evenly distribute the overflow of the roof to N surface grids coupled with the roof, where N is a positive integer greater than or equal to 1.

[0033] In any of the above solutions, preferably, the calculation formula for the overflow of the roof is:

[0034]

[0035] Among them, Q is the overflow, σ s is the flooding coefficient, m is the discharge coefficient, b is the roof width, g is the gravitational acceleration, and h is the height of the runoff depth of the hydrological response unit exceeding the cofferdam.

[0036] The present invention proposes a layered simulation method for surface structures in a community, which does not require refined roof elevation data, reduces the number of model grids to a certain extent, and reduces calculation complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The present invention is a flow chart of a preferred embodiment of the method for simulating layered surface structures in a community according to the present invention.

[0038] Figure 2 A drainage diagram of a high-rise building according to an embodiment of the method for simulating layered surface structures in a community according to the present invention.

[0039] Figure 3 A drainage diagram of a multi-story building according to an embodiment of the method for simulating layered surface structures in a community according to the present invention.

[0040] Figure 4 A drainage diagram of a low-rise building according to an embodiment of the method for simulating layered surface structures in a community according to the present invention.

[0041] Figure 5 It is a schematic diagram of the coupling relationship between the hydrological response unit and the surface grid unit according to an embodiment of the layered simulation method of surface structures in a community of the present invention.

[0042] Figure 6 It is a schematic diagram of the coupling relationship between the hydrological response unit and the pipe network node unit according to an embodiment of the layered simulation method of surface structures in a community of the present invention.

[0043] Figure 7 It is a schematic diagram of numerical simulation of roof runoff according to an embodiment of the layered simulation method of surface structures in a community according to the present invention.

[0044] Figure 8 A schematic diagram of the topographic distribution of roof runoff according to an embodiment of the method for simulating the layered surface structures in a community according to the present invention.

[0045] Fig. 9 It is a schematic diagram of a building elevation method according to an embodiment of the maximum surface flooding depth process of the method for simulating layered surface structures in a community according to the present invention.

[0046] Fig.10 A schematic diagram of a surface structure layering method according to an embodiment of the maximum surface flooding depth process of a method for simulating layering of surface structures in a community according to the present invention.

[0047] Fig.11 A schematic diagram of a building elevation method for simulating flow field distribution for 50 minutes according to an embodiment of the layered simulation method for surface structures in a community of the present invention.

[0048] Fig.12 A schematic diagram of a surface structure layering method for simulating flow field distribution for 50 minutes according to an embodiment of the method for simulating layering of surface structures in a community of the present invention.

[0049] Fig.13 It is a schematic diagram of numerical simulation of building flooding according to an embodiment of the layered simulation method of surface structures in a community of the present invention.

[0050] Fig.14 A schematic diagram of terrain distribution of an embodiment of building flooding according to the method for simulating layered surface structures in a community of the present invention.

[0051] Fig.15 It is a schematic diagram of the process of an embodiment of the water depth change of the grid inside the building according to the layered simulation method of the surface structure in the community of the present invention.

[0052] Fig.16 This is a schematic diagram of the results of a 150-minute flow field in a study area according to an embodiment of the method for simulating the layered surface structures in a community according to the present invention. DETAILED DESCRIPTION

[0053] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0054] Embodiment 1

[0055] like Figure 1As shown, a method for simulating the layering of surface structures in a community is performed, step 100 is executed to obtain building information, the building information includes building roof type and building floor information, the building roof type is generalized into two types, permeable roof and impermeable roof; the building floor information includes building height and building number of floors.

[0056] Execute step 110, use the hydrological response unit to simulate the runoff process of the building roof, and use the runoff coefficient method to calculate the runoff process of the roof. The formula is:

[0057] R=α×P

[0058] Among them, R is the runoff depth of the roof, α is the runoff coefficient, and P is the average rainfall depth in the corresponding period;

[0059] The runoff coefficient α of the impermeable roof is 1.00, and the runoff coefficient α of the permeable roof ranges from 0.30 to 0.40.

[0060] Execute step 120, simulate the confluence process of the building itself with a two-dimensional surface model, determine the connection method of the building drainage system, and simulate the confluence process according to the connection method; for the high-rise building and the multi-story building, establish the coupling relationship between the hydrological response unit and the surface grid unit and the pipe network node unit according to the actual position of the downpipe.

[0061] The connection methods include connection methods for high-rise buildings and multi-story buildings, and connection methods for low-rise buildings.

[0062] High-rise buildings refer to residential buildings with a height greater than 27 meters and other non-single-story civil buildings with a height greater than 24 meters;

[0063] A multi-storey building refers to a building that meets the conditions of 10 meters < multi-storey building height < 24 meters and 3 floors < building number of floors < 7 floors;

[0064] A low-rise building refers to a building with a height of less than or equal to 10 meters and a number of floors less than or equal to 3.

[0065] The runoff calculation steps for high-rise and multi-story buildings are as follows:

[0066] Step 201: The hydrological response unit calculates the runoff depth using the runoff coefficient method;

[0067] Step 202: multiplying the runoff depth by the area of ​​the hydrological response unit to obtain the runoff volume;

[0068] Step 203: evenly distribute the runoff to M surface grids and pipe network nodes coupled thereto, where N is a positive integer greater than or equal to 1.

[0069] The runoff calculation steps for the low-rise building are as follows:

[0070] Step 211: The hydrological response unit calculates the runoff depth using the runoff coefficient method;

[0071] Step 212: Use the weir flow formula to calculate the overflow of the roof. The calculation formula for the overflow of the roof is:

[0072]

[0073] Among them, Q is the overflow, σ s is the flooding coefficient, m is the discharge coefficient, b is the roof width, g is the gravity acceleration, and h is the height of the runoff depth of the hydrological response unit exceeding the cofferdam;

[0074] Step 213: evenly distribute the overflow of the roof to N surface grids coupled with the roof, where N is a positive integer greater than or equal to 1.

[0075] Embodiment 2

[0076] The present invention is based on the water flow movement mechanism of buildings in urban environments. The building unit is both a flow-generating unit and a flow-converging unit. A layered method is proposed to simulate the flow generation and confluence process of buildings, a "hydrological response unit" method is used to simulate the flow generation process of the building roof, and a two-dimensional surface model is used to simulate the flow confluence process of the building itself.

[0077] The roofs of buildings are generalized into two types, permeable units and impermeable units. One is an impermeable roof, that is, the infiltration process of the roof is not considered during the runoff generation process, and the other is a green roof, that is, the infiltration effect of the roof is considered during the runoff generation process.

[0078] The runoff generation and convergence process of the roof is calculated using the runoff coefficient method. The runoff coefficient of an impermeable roof is 1.00. Referring to relevant standards and specifications, it is recommended that the runoff coefficient of a green roof be in the range of 0.30-0.40.

[0079] R=α×P (1)

[0080] Among them, α is the runoff coefficient, P is the average rainfall depth in the corresponding period, and R is the runoff depth of the roof.

[0081] There are many different ways to construct drainage systems in buildings, such as Figure 2-4 As described above, the connection methods are divided into two types. One is the connection method for high-rise and multi-story buildings, and the other is the connection method for low-rise buildings. For both connection methods, first, it is necessary to establish the coupling relationship between the hydrological response unit and other elements. Then, relevant simulation calculations are performed. The specific calculation process of the two connection methods is described as follows.

[0082] like Figure 2The following is a schematic diagram of drainage in a high-rise building. Figure 3 The figure shows the drainage diagram of multi-story buildings. For high-rise and multi-story buildings, the coupling relationship between the hydrological response unit and the surface grid unit and the pipe network node unit is established according to the actual location of the downpipe, as shown in Figure 5 and Figure 6 As shown in the figure, simulating the runoff process on the roof of a building in this way is equivalent to directly converging the net rain on the roof of the building to the nodes of the drainage pipe network system or the lower-level grid units on the surface. The specific calculation method is as follows: first, the hydrological response unit uses the runoff coefficient method to calculate the runoff depth, then multiply the runoff depth by the area of ​​the hydrological unit to obtain its runoff, and finally, the runoff is evenly distributed to multiple surface grids and pipe network nodes coupled with it.

[0083] For low-rise buildings, the coupling relationship between the hydrological response unit and the surrounding surface grid units is established. The specific calculation method is as follows: first, the hydrological response unit uses the runoff coefficient method to calculate the runoff depth, then the weir flow formula is used to calculate the overflow of the roof, as shown in formula (2), and finally, the water volume is evenly distributed to multiple surface grids coupled with it.

[0084]

[0085] Where Q is the overflow (m 3 / s), b is the roof width (m), h is the height of the runoff depth of the hydrological response unit exceeding the cofferdam, and the flooding coefficient σ s and flow coefficient m can be obtained by looking up Table 1.

[0086] Table 1 Weir flow formula coefficient query table

[0087] <![CDATA[h s / H]]> ≤0.80 0.82 0.84 0.86 0.88 0.90 0.92 0.94 0.96 0.98 σs 1 0.99 0.97 0.95 0.90 0.84 0.78 0.70 0.59 0.40 P′ / H ≈0.0 0.20 0.40 0.60 0.80 1.00 2.00 4.00 6.00 8.00 ≈∞ m 0.385 0.366 0.356 0.350 0.345 0.342 0.333 0.327 0.325 0.324 0.320

[0088] like Figure 4 The figure shows the drainage diagram of low-rise buildings. According to the rainfall runoff characteristics and flood inundation characteristics of surface structures, a hierarchical simulation method is proposed. The "hydrological response unit" is used to simulate the roof rainfall runoff process, and the two-dimensional surface model is used to simulate the flood inundation process of the building. Different from the previous simulation methods, this method can not only simulate the roof water runoff process, but also simulate the surface inundation process of the building. At the same time, the method does not require refined roof elevation data, which reduces the number of model grids to a certain extent and reduces the computational complexity.

[0089] Embodiment 3

[0090] In this example, it is assumed that within the 20m×30m area, the study area contains 10m×6m buildings, the buildings flow to the lower surface area through downspouts, and the roofs of the buildings are impermeable, such as Figure 7The figure shows the numerical simulation diagram of roof runoff. The topographic data of the study area, such as Figure 8 The topographic distribution map of roof runoff is shown in Figure 1. The topography decreases from the building area to the surrounding areas. A 1m regular grid is used to construct a two-dimensional fine surface model. The outlet boundary is set as the critical outflow flow, and the other boundaries are set as solid wall boundaries. The location of the downpipe is as follows: Figure 7 As shown, the surface Manning coefficient is 0.035s·m -1 / 3 In this case, the rainfall intensity was 50 mm / h and lasted for 2 hours. The simulation calculation was carried out for 6 hours in total. The simulation calculation was carried out using the hydrological response unit method and the building elevation method.

[0091] The simulation results of the two building simulation methods are as follows: Figure 9-12 As shown in Figure 2, they are the maximum surface flooding depth process and the flow field distribution after 50 minutes of simulation. Fig. 9 and Fig.11 As shown in the figure, the building elevation method is used to simulate the building. Since the roof area is assumed to be a flat area, as the net rain in the roof area occurs, the water on the roof flows evenly to the surrounding grids, and the flow field on the roof is also evenly dispersed around. The hydrological response unit is used to simulate the flow generation process on the roof of the building. At the same time, according to the location of the downpipe, the corresponding surface grid is coupled to analyze the following: Fig.10 and Fig.12 As shown in the simulation results using the hydrological response unit method, the rainwater on the roof will flow to the corresponding coupled surface position through the downpipe under the action of its own gravity. As shown in the flow field diagram, the water that flows from the roof to the surface will disperse and flow from the grid at the downpipe position to the surrounding area.

[0092] The case shows that the hydrological response unit method can be used to simulate the roof runoff process of buildings. On the one hand, it can generalize the roof runoff process more realistically, and on the other hand, it does not require detailed elevation data of the roof. For urban areas, it can improve calculation efficiency and reduce calculation complexity.

[0093] Embodiment 4

[0094] In this embodiment, the building flooding case, such as Fig.13 The figure shows the numerical simulation of building flooding. All boundaries in the entire area are set as solid wall boundaries. Topographic data of the study area, Fig.14 The figure shows the topographic distribution of the building flooded by water. The topography decreases from the building area to the surrounding areas. The building elevation is slightly higher than the surrounding areas. In addition, the surrounding areas are set as weir flow edges to block water. Fig.13As shown, the building contains a door with a width of about 0.5m, which allows water to enter the building. In the simulation, the building's open door function is generalized by a dike-type edge with a gap of 0.5m wide. The rainfall intensity is 50mm / h and lasts for 8 hours. The simulation calculation is carried out for a total of 12 hours.

[0095] Building flooding simulation results, such as Figure 15-16 As shown in Figure 2, the water depth variation process of the grid inside the building is as follows: Fig.15 As shown in the figure, the flow field diagram of the study area for 150 minutes is as follows: Fig.16 At the beginning of the simulation, the surface runoff flows along the terrain to the surrounding low-lying areas. As the rainfall continues, at 143 minutes of simulation time, the building area begins to be flooded. After the building is flooded, as shown in the flow field diagram, the surface runoff disperses and flows from the door position to the inside of the building. As the rainfall continues to increase, the water depth in the building is also increasing. After 8 hours, as the rainfall stops, the water depth in the building will maintain a fixed depth and will no longer increase.

[0096] The building layering method proposed in this embodiment is equivalent to generalizing the building area into a two-layer structure, namely the roof runoff generation layer and the building runoff collection layer. During the simulation process, the hydrological response unit is used to simulate the runoff generation process of the building, and the two-dimensional surface model is used to simulate the building flooding process. Then, through the established coupling relationship, the net rain on the roof of the building is discharged to the surface area with lower terrain. As the surface water gradually increases, the surface runoff can be collected into the building. By setting a cofferdam with a gap around the building, the building water inflow process can be simulated. The building elevation method regards the building as a single-layer structure. This method cannot simulate the building water inflow and flooding process.

[0097] In order to better understand the present invention, the above is described in detail in conjunction with the specific embodiments of the present invention, but it is not intended to limit the present invention. Any simple modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention. Each embodiment in this specification focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referenced to each other. For the system embodiment, since it basically corresponds to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

Claims

1. A method for stratifying surface structures in a community, comprising obtaining building information, and further comprising the following steps: Step 1: Use the hydrological response unit to simulate the runoff process on the roof of the building; Step 2: Simulate the confluence process of the building itself with a two-dimensional surface model, determine the connection method of the building drainage system, and simulate the confluence process according to the connection method; The connection methods include connection methods for high-rise buildings and multi-story buildings, as well as connection methods for low-rise buildings; For the high-rise building and the multi-story building, according to the actual location of the downpipe, the coupling relationship between the hydrological response unit and the surface grid unit and the pipe network node unit is established. The runoff calculation steps for the high-rise building and the multi-story building are as follows: Step 201: The hydrological response unit calculates the runoff depth using the runoff coefficient method; Step 202: multiplying the runoff depth by the area of ​​the hydrological response unit to obtain the runoff volume; Step 203: evenly distribute the runoff to M surface grids and pipe network nodes coupled thereto, where M is a positive integer greater than or equal to 1; The runoff calculation steps for the low-rise building are as follows: Step 211: The hydrological response unit calculates the runoff depth using the runoff coefficient method; Step 212: Calculate the overflow of the roof using the weir flow formula. The calculation formula for the overflow of the roof is: ， in, Q is the overflow volume, σ s is the flooding coefficient, m is the flow coefficient, b is the roof width, g is the acceleration due to gravity, h The runoff depth of the hydrological response unit exceeds the height of the cofferdam; Step 213: evenly distribute the overflow of the roof to N surface grids coupled with the roof, where N is a positive integer greater than or equal to 1.

2. The method for stratifying surface structures in a community as claimed in claim 1, characterized in that: The building information includes building roof type and building floor information.

3. The method for stratifying surface structures in a community as claimed in claim 2, characterized in that: The building roof types are generalized into two types, permeable roofs and impermeable roofs.

4. The method for stratifying surface structures in a community as claimed in claim 3, characterized in that: The step 1 includes calculating the runoff coefficient method for the flow generation process on the roof, and the formula is: R = α × P in, R is the runoff depth of the roof, α is the runoff coefficient, P is the average rainfall depth during the corresponding period.

5. The method for stratifying surface structures in a community as claimed in claim 4, characterized in that: The runoff coefficient of the impermeable roof α is 1.00, the runoff coefficient of the permeable roof α The value range is 0.30-0.

40.

6. The method for stratifying surface structures in a community as claimed in claim 1, characterized in that: The high-rise buildings refer to residential buildings with a height greater than 27 meters and other non-single-story civil buildings with a height greater than 24 meters.

7. The method for stratifying surface structures in a community as claimed in claim 6, characterized in that: The multi-storey building refers to a building that satisfies 10 meters < multi-storey building height < 24 meters and 3 floors < number of floors < 7 floors.

8. The method for stratifying surface structures in a community as claimed in claim 1, characterized in that: The low-rise building refers to a building with a height of less than or equal to 10 meters and a number of floors less than or equal to 3.

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