Calculation method of debris flow impact building vulnerability based on FLO-2D and ABAQUS

Abstract

The present invention is a method for calculating the vulnerability of debris flow impacting buildings based on FLO-2D and ABAQUS. The steps of the calculation method are: using FLO-2D software to simulate debris flow events, recording the debris flow velocity and flow depth at different times; calculating the total impact pressure at different times; modeling the building in ABAQUS, applying the relationship data of the total impact pressure and time to the building model, and calculating the stiffness failure cloud map at different times; calculating the stiffness failure grid ratio P i ; Draw P i The functional relationship graph of i; the building vulnerability at the moment of the first slope mutation in the graph is defined as 1, and the stiffness failure grid ratio is P j，max ; P i With P j，max The value of the building's vulnerability V at the i-th moment is determined by comparison. For the first time, the combination of FLO‑2D and ABAQUS realizes a complete quantitative assessment of the building's vulnerability, making the calculation results more accurate.

Description

Technical Field

[0001] The invention belongs to the field of engineering geological research, and in particular relates to a method for calculating the vulnerability of debris flow impacting buildings based on FLO-2D and ABAQUS. Background Art

[0002] Debris flow is a solid-liquid two-phase flow of fluid mainly containing sediment, gravel, large rocks and other materials. It mainly develops in mountainous areas and is a common type of geological disaster. The formation process of debris flow is very complicated, and the outbreak process is often accompanied by disasters such as collapse, floods and landslides. This is because the debris flow outbreak process is sudden, the duration is short, the momentum is extremely fierce, and the destructive power is amazing. Therefore, debris flow has developed into a natural disaster that needs special attention in my country's mountainous areas, and has seriously hindered the pace of economic construction in my country's mountainous areas.

[0003] my country has a vast mountainous area, accounting for about two-thirds of the country's land area. These mountainous areas have natural conditions for debris flow, including strong neotectonic movement, large earthquake intensity, complex and changeable terrain, steep slopes, broken surface, high-intensity rainstorms, and low vegetation coverage due to human deforestation. The natural conditions for the formation of debris flow make these areas widely distributed, with high frequency and large number of debris flow, and my country has become one of the typical countries in the world that are deeply affected by debris flow.

[0004] However, due to the complexity of debris flow movement and the uncertainty of building structure dynamic response, quantitative evaluation of building vulnerability is still a major challenge. Currently, there are few methods to make a complete quantitative assessment of the vulnerability of houses under debris flow impact. In the article "Numerical simulation of the destruction mechanism and protective structure of brick masonry houses under debris flow impact", Zhao Xiaoyun simulated the destruction process of brick masonry houses under debris flow impact based on ABAQUS and combined with the calculation formulas of uniformly distributed force of debris flow slurry and concentrated force of blocks. However, when calculating the impact load, it only used the formula to calculate the instantaneous load when the debris flow impacted the masonry structure, without introducing the concept of "action time"; in addition, it did not consider the coupling between sediment, gravel and mud.

[0005] In "Numerical Simulation Study on Frame Structure under Debris Flow Impact", Li Jian used ANSYS software to simulate the destruction process of frame structure, but it was insufficient in solving structural nonlinear problems when simulating structural components, while ABAQUS software has obvious advantages in solving such problems.

[0006] In summary, in response to the existing problems of selecting debris flow velocity and debris flow depth and the nonlinear problem of building components that needs to be solved urgently, the present invention provides a new calculation method for the vulnerability of debris flow impacting buildings based on FLO-2D and ABAQUS numerical simulation. Summary of the invention

[0007] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a method for calculating the vulnerability of buildings to debris flow impact based on FLO-2D and ABAQUS. This method aims to solve the existing problems of quantifying the disaster resistance of buildings under the action of debris flow and the disaster intensity of debris flow, as well as the disadvantage of low quantification degree, which is of great significance for the effective implementation of debris flow risk assessment and reasonable early warning.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is specifically as follows:

[0009] A method for calculating the vulnerability of debris flow impacting buildings based on FLO-2D and ABAQUS, the steps of the calculation method are:

[0010] S1. Obtaining relevant information of debris flow and basic information of buildings within the debris flow threat range, wherein the relevant information of debris flow includes debris flow basin range, debris flow soil information, and debris flow clean water flow data; the basic information of buildings includes building information and structural information;

[0011] S2. Use FLO-2D software to simulate debris flow events and perform parameter inversion of solid-liquid mixtures, and record the debris flow velocity v at different times when the debris flow moves to the location of the building. c and debris flow depth h;

[0012] S3, calculating the total impact pressure on the building when the debris flow moves to the location of the building at different times, and obtaining a set of relationship data between the total impact pressure and time;

[0013] S4, modeling the building in ABAQUS to obtain a building model, applying the relationship data between the total impact pressure and time calculated in step S3 to the building model, meshing the built building model, and calculating and outputting the stiffness failure cloud map of the building model at different times;

[0014] S5. Check and count the number of meshes that have experienced stiffness failure in the divided meshes at different times; and make a ratio between the number of meshes that have experienced stiffness failure and the total number of meshes, and define the ratio as P i , i represents the time; P at different times is plotted i The graph of the function relationship with i;

[0015] S6. Observation Pi The functional relationship graph of i defines the building vulnerability at the moment of the first slope mutation as 1, and stipulates that the ratio at this time is P j，max ; The ratio P at the i-th moment i With P j，max For comparison, P i / P j，max Determine the value of the vulnerability V of this type of building at the i-th moment.

[0016] Furthermore, the total impact pressure p is calculated according to formula (3):

[0017]

[0018] Among them, p st is the average static pressure of debris flow, in N / m 2 ; ρ is the average density of debris flow soil, unit: kg / m 3 ; g is the acceleration of gravity, unit N / kg; h is the depth of debris flow, unit m; λ is the shape coefficient of the building; v c is the velocity vector of debris flow, in m / s; α is the angle between the force-bearing surface of the building and the direction of the debris flow pressure, in degrees;

[0019] The debris flow velocity v at different times obtained in step S2 is c Substitute the debris flow depth h into formula (3) and use formula (3) to calculate a set of data on the total impact pressure of the debris flow on the building when the debris flow moves to the location of the building at different times.

[0020] Furthermore, the calculation method is used to evaluate the vulnerability of buildings on the path of debris flow and the risk resistance design of buildings, to evaluate the vulnerability of a specific building under a specific stiffness, and then to evaluate the loss of life and property of such buildings after they may be hit by a debris flow based on the vulnerability values ​​of such buildings at different times; or to provide a design basis for how to improve the anti-destruction performance of buildings under the total impact intensity of the debris flow.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) This paper combines FLO-2D and ABAQUS for the first time to achieve a complete quantitative assessment of building vulnerability, making the calculation results more accurate.

[0023] (2) This paper first uses a new evaluation system. The system first obtains the debris flow velocity and flow depth at different times through FLO-2D simulation, then converts the dynamic pressure, and then applies the dynamic pressure to the building through ABAQUS. The "stiffness failure" model in ABAQUS is used for the first time to quantitatively evaluate the vulnerability of the building. Finally, the ratio of the number of grids with stiffness failure to the total number of grids is used as the ratio P i As a relevant parameter for evaluating the vulnerability of buildings.

[0024] (3) The present invention adopts a connection method of binding the column-beam connection surface in ABAQUS to solve the problem that shear and buckling failures are prone to occur at the beam end of the connection surface due to the difference in stiffness between the beam and the column.

[0025] (4) The present invention determines the buildings that may be affected by the debris flow based on the simulation of the debris flow movement process, and then uses the simulation results to quantitatively determine the vulnerability of the buildings that may be affected by the debris flow intensity, providing a new idea for government departments to carry out risk assessment and management. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Depth distribution of debris flow in Jiwozi Village simulated by FLO-2D at 2.5s

[0027] Figure 2 The debris flow velocity distribution map of Jiwozi Village simulated by FLO-2D at 2.5s.

[0028] Figure 3 A set of data on the total impact pressure of debris flows onto buildings in Jiwozi Village at different times.

[0029] Figure 4 Stiffness failure mesh ratio P of a building model in Jiwozi Village i Relationship diagram with time.

[0030] Figure 5 A building in Jiwozi Village 2.5,max Stiffness failure cloud map of the building model at the time.

[0031] Figure 6 A building in Jiwozi Village 2 Stiffness failure cloud map of the building model at the time. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Of course, the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0033] The present invention is based on the debris flow impact building vulnerability calculation method of FLO-2D and ABAQUS, using FLO-2D software and ABAQUS software to perform numerical simulation coupling analysis, including the following steps:

[0034] S1. Obtain relevant information about debris flow and basic information about buildings within the debris flow threat range

[0035] Collect basic information about debris flow, debris flow soil and buildings within the debris flow threat range, understand the mechanism and path of debris flow on buildings,

[0036] The relevant information of debris flow includes: debris flow basin range, debris flow soil information, debris flow clean water flow data, more specifically, the average density of debris flow soil ρ, the width of debris flow on the structure b, and the data required for FLO-2D modeling. The debris flow clean water flow data is used to obtain the size of the clean water flow of the debris flow through the inflow point.

[0037] The basic information of the building includes: architectural information, structural information and data required for ABAQUS modeling;

[0038] Data required for FLO-2D modeling: geological information and hydrological information of the disaster area. Debris flow severity, elevation terrain DEM data, Manning coefficient (n) within the watershed, debris inflow point shp.file obtained through remote sensing images and field surveys. Debris inflow point shp.file is directly imported into FLO-2D to make inflow points. Manning coefficient is used to reflect surface roughness information. The rougher the surface, the greater the Manning coefficient.

[0039] Data required for ABAQUS modeling: building area, material information of beams, slabs, columns and steel bars.

[0040] S2. Based on the elevation terrain DEM data, debris flow basin range, debris flow clean water flow data, debris inflow point shp. file obtained from the survey, and the Manning coefficient, yield stress, viscosity coefficient, laminar flow resistance coefficient and other data obtained by referring to the "FLO-2D User Manual" and comparing them with the conditions of the study area, these parameters of the debris flow fluid and the debris inflow point shp. file were input into the FLO-2D software to simulate the debris flow event and perform parameter inversion of the solid-liquid mixture, and finally the debris flow velocity v when the debris flow moves to the location of the building at different times was obtained. c and the debris flow depth h, the flow velocity v is obtained c Flow depth h diagram.

[0041] S3, calculating the total impact pressure on the building when the debris flow moves to the location of the building at different times, and obtaining a set of relationship data between the total impact pressure and time;

[0042] For building structures under the impact of fast-moving debris flows, the debris flows have two kinds of pressure effects on them: rapid impact pressure and static pressure of debris flow accumulation when the movement stops.

[0043] Static pressure effect of debris flow accumulation:

[0044]

[0045] Where p st is the average static pressure of debris flow, in N / m 2 ; ρ is the average density of debris flow soil, unit: kg / m 3 ; g is the acceleration due to gravity, unit is N / kg; h is the depth of the debris flow at this point, unit is m.

[0046] Impact pressure of debris flow:

[0047]

[0048] Where p dy is the impact pressure of debris flow, in N / m 2 ;v c is the velocity vector of debris flow, in m / s; λ is the building shape factor, where the circular building is 1.0 and the rectangular building is 1.33; ρ is the average density of debris flow soil, in kg / m 3 ; α is the angle between the load-bearing surface of the building and the direction of the debris flow pressure, unit "°".

[0049] Combining the above two equations, the final total impact pressure of the debris flow is as follows:

[0050]

[0051] The derivation process of formula (3) can be referred to the Code for Design of Debris Flow Prevention and Control Engineering T / CAGHP021-2018.

[0052] The debris flow velocity v at different times obtained in step S2 is c Substitute the debris flow depth h into formula (3) and use formula (3) to calculate a set of data on the total impact pressure of the debris flow on the building when the debris flow moves to the location of the building at different times.

[0053] S4. Using the basic information of the building, create accessories such as beams, slabs, and columns in ABAQUS, and assign material cross-sectional properties; assemble the components to form a building model; set relevant analysis steps; determine the interaction between the components, the binding between beams, slabs, and columns, and the embedding between steel bars and various parts; determine the boundary conditions, input the total impact pressure at different times calculated in step S3, and apply the total impact pressure to the action surface of the building model;

[0054] Apply the relationship data of the total impact pressure and time obtained in step S3 to the building; mesh the building model, calculate and output the stiffness failure cloud map of the building model at different times;

[0055] S5. Check and count the number of meshes that have experienced stiffness failure in the divided meshes at different times; and make a ratio between the number of meshes that have experienced stiffness failure and the total number of meshes, and define the ratio as P i , i represents the time; P at different times is plotted i The graph of the function relationship with i;

[0056] S6. Observation P i The functional relationship graph of i defines the building vulnerability at the moment of the first slope mutation as 1. And the ratio at this time is defined as P j，max ; The ratio P at the i-th moment i With P j，max For comparison, P i / P j，max Determined as the value of the vulnerability V of this type of building at the i-th moment, the specific calculation formula is formula (4):

[0057]

[0058] Among them, the value range of V is between 0 and 1. If P i / P j，max If the value of is greater than 1, set it to 1.

[0059] The calculation method of the present invention is intended to provide a basis for the vulnerability assessment of other buildings on the path of debris flow and the risk resistance design of buildings. The present invention can provide a vulnerability evaluation for a specific building under a specific stiffness, and then evaluate the loss of life and property of such buildings after a possible debris flow according to the vulnerability values ​​of such buildings at different times; or provide a design basis for how to improve the anti-destruction performance of the building under the total impact intensity of the debris flow (the anti-destruction performance of the building can be improved by increasing the cross-sectional size of each component, the material strength of each component, and the number of each component).

[0060] The specific steps of S4 are:

[0061] 4.1) Open ABAQUS, select "Use Standard / Explicit model", select the appropriate unit size, and the corresponding units of force, mass, time, stress, etc.

[0062] 4.2) Create beams, slabs, columns, stress-bearing bars, stirrups and other components in sequence. For steel bars, input their elastic modulus, density, plasticity and other related data; for concrete, when inputting material information, add relevant data such as the concrete damage (CDP) model. This data input plays a key role in the subsequent export of the building stiffness failure cloud map.

[0063] 4.3) Assemble the components, that is, assemble them according to their positions. After assembly, bind the beams, plates and columns, and assemble the steel bars in their respective parts using the "built-in area" method. At this point, a complete model is assembled.

[0064] 4.4) Select the analysis step in the module. When creating the analysis step, select "Dynamic, Explicit". The time interval of the analysis step is determined based on the time and interval obtained by simulation in FLO-2D.

[0065] 4.5) According to the environmental conditions around the building, different boundary conditions are applied (if there are no other buildings around, only the column base is "fully fixed", that is, the column base is set to have no displacement and rotation. If there are constraints around, the building needs to be subject to corresponding displacement restrictions.), according to the velocity and depth data of the debris flow at different times obtained by FLO-2D, combined with formula (3), the pressure magnitude at different times is calculated, and then an amplitude table is created in ABAQUS, and each time and the corresponding total impact pressure at each time are input into the amplitude table for applying the total impact pressure. Then select the component to which the total impact pressure is to be applied.

[0066] 4.6) Divide the model into grids. When dividing the grids, you can set the uniform cell side length to directly divide the model; you can also divide different parts into different grid sizes. For example, because the impact pressure of debris flow is mainly lateral impact, it has a greater impact on the column, so the column grid is divided into smaller sizes to improve accuracy. For beams and plates, the lateral impact has less impact on them, so the grid can be divided into larger sizes to improve calculation efficiency.

[0067] 4.7) Assign all components to dynamic calculations, then create a "job", start the calculation, and get the results; export the stiffness failure cloud diagram of the building model at different times.

[0068] About grid division: ABAQUS is a finite element software. For simulation calculations of finite element software, the software usually divides a large model into countless small "cells", and then calculates each small "cell" to get the final result. Here, the "cell" is the grid. The smaller the grid, the more grids the model is divided into, the greater the calculation accuracy and the longer the calculation time.

[0069] Example 1

[0070] The case of this study is the debris flow in Jiwozizi Village. Jiwozizi Village is located in Jiwozizi Group, Weiziping Village, Luanzhen Street, Chang'an District, Xi'an City, Shaanxi Province. On August 11, 2023, after on-site investigation and drone survey by water conservancy experts, preliminary analysis showed that the cause of the disaster was the blockage of the channel caused by the collapse of the upstream mountain, and the accumulation of floods broke through the blocking body, causing mountain torrents and debris flows. 21 victims have been found in the Xi'an debris flow, and 6 people are still missing. The mountain torrents and debris flow in Weiziping Village, Xi'an have caused 4 deaths.

[0071] In order to study the impact of debris flow on buildings, a frame structure within the impact range of the debris flow was selected. The density of the debris flow is: 2.65×10 4 kg / m 3 The basic information of the building is: the structural floor height is 3900mm, the span is 5000mm, the column cross-section area is 400mm×400mm, the beam cross-section width is 550mm×250mm, the entire building uses C30 concrete, and the steel grade is HRB400.

[0072] Step S1: Through field investigation and data purchase, we can obtain the average soil density ρ of the debris flow in Jiwozi Village, the width b of the debris flow on the building; the geological and hydrological information of the disaster area (debris flow severity, elevation terrain DEM data, Manning coefficient (n) within the basin, debris flow clear water flow data, and debris flow point SHP files obtained through remote sensing images and field investigation); building area, beam, slab, column size and other building information. Structural information such as building concrete strength, steel bar type, reinforcement information, etc.

[0073] Step S2:

[0074] First, the physical simulation model was established in FLO-2D using the elevation terrain DEM data of Jiwozi Village obtained by S1; then the physical simulation model was divided into 12m×12m cells in the software; then the terrain of the area was assigned values, including: Manning coefficient n, clean water flow data, and debris flow severity. Then the shp. file of the debris inflow point was imported into FLO-2D to generate the inflow point. Finally, the debris flow event was simulated and the required debris flow depth and velocity maps at different times were exported.

[0075] After FLO-2D simulation, Figure 1 , 2 As shown in the figure, the debris flow velocity v when the debris flow hits the building 2.5s after the debris flow hits the building is obtained. c =2m / s, the accumulation thickness of the debris flow deposit here is h=2.4m.

[0076] Step S3:

[0077] In this embodiment, the rectangular building is λ = 1.3; α is the angle between the force-bearing surface of the building and the direction of the debris flow pressure, α = 90°, and the debris flow density is: ρ = 2.65 × 10 4 kg / m 3 According to formula (3), the total impact pressure on the building caused by the debris flow at different times when it moves to the location of the building is calculated, and a set of pressure and time relationship data is obtained; the flow depth and flow velocity data at 2.5s are taken as an example, and the data are substituted into formula (3) to obtain:

[0078]

[0079] The total impact pressure values ​​at other times can be found in Figure 3 .

[0080] Step S4:

[0081] Open ABAQUS, select "Use Standard / Explicit model", and use mm as the unit for modeling. The corresponding units of force, mass, time, and stress are: force is N, mass is t, time is s, and stress is MPa.

[0082] Based on the building data obtained from the on-site investigation, components including beams, slabs, columns, stress bars, stirrups, etc. are created in sequence, and their respective material properties are applied to the materials. In particular, for concrete, relevant data on the "concrete damage model" is added.

[0083] When assembling, cut out the section in contact with the beam on the column, select this section as the main section, select the surface of the beam in contact with the column as the secondary section, and select the binding key to bind. Repeat the steps to bind the beam to the column, the beam to the plate, and the column to the plate. Then select "Built-in Area" and click the corresponding steel bars and concrete of each part in turn to inlay the steel bars and concrete. At this point, a building model is generated.

[0084] Select the analysis step in the module of ABAQUS software. When creating the analysis step, select "Dynamic, Explicit". According to the time obtained by FLO-2D simulation, the total simulation time of ABAQUS is finally determined to be 6s, and the analysis step\frame is set to 0.5 seconds.

[0085] When selecting boundary conditions, considering that the building only has the constraint of the foundation, a full constraint method is adopted (that is, there is no displacement or rotation at the bottom of the column). Create an amplitude table in ABAQUS, input each moment and the corresponding pressure at each moment calculated in S3 into the amplitude table, and then select the components to be loaded. Then mesh the model, select the side length of the unit mesh as 100mm, and specify all components for dynamic calculation. Create a "job" and start the calculation. Export the stiffness failure cloud map of the building model at different times.

[0086] In step S5:

[0087] Check and count the number of grids with stiffness failure in the divided grids at different times, that is, the number of stiffness failure units at different times; make a ratio P of the number of stiffness failure units to the total number of grids (13444) i , then draw to get P i -i(time) function graph (see Figure 4 ).

[0088] In step S6:

[0089] Observation P i The functional relationship graph with i shows that when the debris flow is 2.5s (the number of stiffness failure units is 1042) (see Figure 5 ), the slope of the straight line suddenly changes, so the structural fragility at 2.5s is defined as 1 and the ratio is P 2.5，max ,

[0090] Use P at 2s 2 (At this moment, the number of stiffness failure units is 503) (See Figure 6 ) and P at 2.5s 2.5，max Make a ratio,

[0091] Therefore, from formula (4), the building vulnerability V at 2s can be obtained as follows:

[0092]

[0093] Therefore, it is believed that the vulnerability of this type of building under the impact pressure of the debris flow corresponding to the 2s moment is 0.483.

[0094] Any matters not described in the present invention are applicable to the prior art.

Claims

1. A method for calculating the vulnerability of debris flow impacting buildings based on FLO-2D and ABAQUS, characterized in that: The steps of the calculation method are: S1. Obtaining relevant information of debris flow and basic information of buildings within the debris flow threat range, wherein the relevant information of debris flow includes debris flow basin range, debris flow soil information, and debris flow clean water flow data; the basic information of buildings includes building information and structural information; S2. Use FLO-2D software to simulate debris flow events and perform parameter inversion of solid-liquid mixtures, and record the debris flow velocity v at different times when the debris flow moves to the location of the building. c and debris flow depth h; S3, calculating the total impact pressure on the building when the debris flow moves to the location of the building at different times, and obtaining a set of relationship data between the total impact pressure and time; In step S3, the total impact pressure p is calculated according to the following formula: Among them, p st is the average static pressure of debris flow, in N / m 2 ; ρ is the average density of debris flow soil, unit: kg / m 3 ; g is the acceleration of gravity, unit N / kg; h is the depth of debris flow, unit m; λ is the shape coefficient of the building; v c is the velocity vector of debris flow, in m / s; α is the angle between the force-bearing surface of the building and the direction of the debris flow pressure, in "°"; p dy is the impact pressure of debris flow, in N / m 2 ; S4, modeling the building in ABAQUS to obtain a building model, applying the relationship data between the total impact pressure and time calculated in step S3 to the building model, meshing the built building model, and calculating and outputting the stiffness failure cloud map of the building model at different times; S5. Check and count the number of meshes that have experienced stiffness failure in the divided meshes at different times; and make a ratio between the number of meshes that have experienced stiffness failure and the total number of meshes, and define the ratio as P i , i represents the time; P at different times is plotted i The graph of the function relationship with i; S6. Observation P i The functional relationship graph of i defines the building vulnerability at the moment of the first slope mutation as 1, and stipulates that the ratio at this time is P j，max ; The ratio P at the i-th moment i With P j，max For comparison, P i / P j，max Determine the value of the vulnerability V of this type of building at the i-th moment.

2. The calculation method according to claim 1, characterized in that: The specific process of step S4 is: 4.1) Open ABAQUS, select "Use Standard / Explicit Model", select the appropriate unit size, and the corresponding units of force, mass, time, and stress; 4.2) Create components including beams, plates, columns, stress bars, and stirrups in sequence. For steel bars, input their elastic modulus, density, and plasticity related data; for concrete, when inputting material information, add the relevant data of concrete damage model; 4.3) Assemble the components, that is, assemble them according to their positions. After the assembly is completed, bind the beams, plates and columns together, and assemble the steel bars in their respective parts using the "built-in area" method. At this point, a complete model is assembled; 4.4) Select the analysis step in the module of ABAQUS software. When creating the analysis step, select "Dynamic, Explicit". The time interval of the analysis step is determined according to the time and interval obtained by FLO-2D simulation; 4.5) According to the environment around the building, different boundary conditions are applied, and an amplitude table is created in ABAQUS. The total impact pressure corresponding to each moment is input into the amplitude table for applying the total impact pressure; then the component to which the total impact pressure is applied is selected; the rule for applying different boundary conditions is: if there are no other buildings around, only the column base is "fully fixed", that is, the column base is set to have no displacement and rotation; if there are constraints around, the building needs to be subject to corresponding displacement restrictions; 4.6) Divide the model into grids. When dividing the grids, the grid division of the columns is smaller than that of the beams and slabs. 4.7) Assign all components to dynamic calculations, then create a "job", start the calculation, and get the results; export the stiffness failure cloud diagram of the building model at different times.

3. The calculation method according to claim 1, characterized in that: The calculation method is used for assessing the vulnerability of buildings on the path of debris flow and designing buildings to resist risks. It is aimed at evaluating the vulnerability of a certain building under a specified stiffness, and then evaluating the loss of life and property of such buildings after being hit by a debris flow based on the vulnerability values ​​of such buildings at different times.

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