Summary of the invention
In order to overcome above-mentioned deficiency, the purpose of the present invention is by extensive grid carry out region division, to material resource ratio
The different region of example uses different grades of thick tessellated mesh, pays close attention to region refinement, and other area grid roughening provide one
Kind is drawn again based on region and the extensive Landslide Hazards Fast numerical simulation method and system of structured grid, overcomes
It is big to extensive Landslide Hazards numerical simulation time domain in the prior art, number of grid is more, computation rate is slow actually asks
Topic.
To achieve the goals above, the present invention adopts the following technical scheme:
A kind of extensive Landslide Hazards Fast numerical simulation method, includes the following steps:
Step 1: obtaining Landslide Hazards terrain data, source area range, elevation and physical and mechanical parameter;
Step 2: dividing extensive Landslide Hazards zoning;
Step 3: thick tessellated mesh condition being judged, and to the roughening of zoning grid, mesh refinement and grid knot
Structure;
Step 4: numerical simulation calculation being carried out to earth's surface disaster dynamic process using numerical simulation software;
Step 5: the calculated result of n zoning of output, and the calculated result of n zoning is merged into a meter
Calculate region output.
Preferably, the method for Landslide Hazards terrain data is obtained in the step 1 specifically: acquire using unmanned plane
Terrain data, and dem data is generated with 3 d modeling software.
It is furthermore preferred that taking fixed point to fly according to Landslide Hazards range when the acquisition terrain data using unmanned plane
Row, S-ing or the flight of the back-shaped line of flight, the 3 d modeling software are generated using smart3D, Pix4D or Photoscan
Dem data.
Preferably, the method that Landslide Hazards source area range and elevation acquisition are obtained in the step 1 specifically: benefit
The unmanned plane or remote sensing altitude data that front and back occurs with landslide disaster, are subtracted each other by grid, obtain source area range and elevation.
Preferably, the method for Landslide Hazards physical and mechanical parameter is obtained in the step 1 specifically: pass through correlative
Reason experiment of machanics obtains the parameters such as disaster volume density, coefficient of friction by way of tentative calculation.
Preferably, the method for extensive Landslide Hazards zoning is divided in the step 2 specifically: using simply
Be divided by and complementation, obtained extensive Landslide Hazards dem data is divided into n*n region, then will before great Qu
Calculating parameter involved in domain is assigned to n*n region, and the equivalence after guaranteeing region division, wherein n is according to different calculating
Precision and computer capacity carry out value.
Preferably, the method judged in the step 3 thick tessellated mesh condition specifically includes: according to calculating pair
As carrying out grid thickness to different zonings, using material resource as Rule of judgment, i.e., no material resource does not need the area calculated
Grid roughening in domain has the calculative area grid refinement of material resource, the grade that simultaneous selection is roughened, refines, such as zoning
Material resource amount is more than 50% grid constantly to refine to two-stage, zoning have material resource but material resource amount less than 50% by mesh refinement
Level-one;Or grid is roughened using Time step as Rule of judgment, such as initial time step, it is carried out with calculating, material resource
Amount increases, subsequent time step grid roughening;Different thickness conditions is used according to oneself calculating needs and computation rate etc. simultaneously.
Preferably, the method that area grid refinement is calculated in the step 3 specifically includes:
(1) refinement levels are set, and every level-one refinement includes to grid node number, sizing grid and grid virtual number of nodes
Refinement, implement such as formula 1:
(nx) '=2* (nx) -1
(ny) '=2* (ny) -1
(dx) '=0.5* (dx)
(dy) '=0.5* (dy)
(mbc) '=2* (mbc)
Formula 1
Wherein, nx, (nx) ' indicate to divide the direction forward and backward calculating grid x number of nodes;Ny, (ny) ' indicate to divide forward and backward meter
Calculate net (dy) ' the direction lattice y number of nodes;Dx, (dx) ' indicate to divide the direction forward and backward calculating grid x element length;Dy indicates to divide
The direction forward and backward calculating grid y element length;Mbc, (mbc) ' indicate to divide forward and backward calculating grid virtual number of nodes;
(2) to cell node assignment after refinement: respectively including carrying out assignment with the point of refinement front unit conode, in x and y
Direction newly refines node of the cell node between two cell nodes and carries out assignment, and the new node that refines is among rectangular element
Node carries out assignment;
(3) boundary condition is assigned to the region after thin draw, boundary condition includes symmetrical boundary condition, open boundaryconditions, wall
Boundary condition.
Preferably, the method that area grid roughening is calculated in the step 3 specifically includes:
(1) setting roughening grade, every level-one roughening includes grid node number, sizing grid and grid virtual number of nodes
Roughening, it is that odd number or even number save the last one if present node number is even number that every level-one roughening, which is divided into present node number,
Point is used as dummy node;
When number of nodes is odd number, every level-one roughening is such as formula 2:
(nx) '=((nx)+1)/2
(ny) '=((ny)+1)/2
(dx) '=2* (dx)
(dy) '=2* (dy)
(mbc) '=(mbc)/2
Formula 2
Wherein, nx, (nx) ' indicate to divide the direction forward and backward calculating grid x number of nodes;Ny, (ny) ' indicate to divide forward and backward meter
Calculate the direction grid y number of nodes;Dx, (dx) ' indicate to divide the direction forward and backward calculating grid x element length;Dy, (dy) ' indicate to divide
The direction forward and backward calculating grid y element length;Mbc, (mbc) ' indicate to divide forward and backward calculating grid virtual number of nodes;
(2) to cell node assignment after roughening: mainly carrying out assignment to the point of new roughening unit and former unit conode, examine
Considering number of nodes may be for even number, and assignment procedure need to judge to be roughened whether posterior nodal point is more than roughening prosthomere points in advance, then into
Row assignment;
(3) boundary condition is assigned to the region after roughening, boundary condition mainly includes symmetrical boundary condition, opens perimeter strip
Part, wall boundary condition.
Preferably, the method that area grid structuring is calculated in the step 3 specifically includes:
Which target area the dummy node unit of inquiry current region is located in;
The dummy node unit of current region is inquired in which unit of target area;
Utilize the design parameter of the dummy node unit of 5 shape function interpolation calculation current region of formula 3- formula:
Formula 3
N1=β1(x-1)(y-1)
N2=β2(x+1)(y-1)
N3=β3(x+1)(y+1)
N4=β4(x-1)(y+1)
Formula 4
Formula 5
Wherein, u indicates the relevant parameter of the dummy node unit of current region, such as height h, the momentum hu of the direction x speed,
The momentum hv etc. of the direction y speed.
Preferably, the step 4 specifically includes: the step 4 specifically includes: the numerical simulation software uses
Massflow software carries out numerical simulation meter to earth's surface disaster dynamic process according to the result of step 1, step 2 and step 3
It calculates.
Preferably, the step 5 specifically includes: the calculated result of n zoning of output, as a result with dem or
The calculated result of n zoning, is merged into according to different-format using Arcgis or tecplot by the output of tecplot format
One region is exported.
The present invention also provides a kind of extensive Landslide Hazards Fast numerical analogue simulation systems, including memory and place
Manage device, in which:
The memory is for storing program instruction;
The processor is for running described program instruction, to execute following steps:
Obtain geological disaster terrain data, source area range and elevation h and physical and mechanical parameter;
Divide extensive Landslide Hazards zoning;
The roughening of zoning grid, mesh refinement and network;
Numerical simulation calculation is carried out to earth's surface disaster dynamic process using simulation softward Massflow;
The calculated result of n zoning is exported, and the calculated result of n zoning is merged into a zoning
Output.
Compared with the prior art, the invention has the following advantages:
(1) extensive grid computing, improve computation rate: the present invention is right by carrying out region division to extensive grid
The different region of material resource ratio uses different grades of thick tessellated mesh, pays close attention to region refinement, and other area grids are roughened,
Due to many geological disasters, its motion path often only accounts for its slope surface landform sub-fraction, and above-mentioned strategy had both been avoided that extensive
Large-scale area is narrowed down to the zonule paid close attention to by the calculating in some non-material resource regions in region, guarantees computational accuracy,
Calculation amount can be saved again, improve computation rate.
(2) dynamic adjusts the thickness of zoning grid: the present invention not only needs and calculates speed to calculate according to oneself
Rate etc. uses different thickness conditions, more it is essential that Landslide Hazards are a Dynamic Evolutions, with landslide ground
The dynamic evolution of matter disaster, grid carries out dynamic thickness according to variations such as region material resource amounts, thus change of the grid with calculating
Change and changes, thus the region that more accurate calculating needs emphasis to calculate, such as in a super large basin, such as bridge pier,
The thin portions structure such as debris dam and drainage groove needs fine grid blocks that can just portray local feature, therefore structured grid and with calculating
Process grid divides with the obvious advantage again.
(3) structured grid and grid node interaction: the present invention is to realize the feature modeling in region and intending for boundary node
It closes, need to grid node structuring, traditional structured grid generation technique usually be utilized indirect method, be carried out by other grids
It generates, not anxious low efficiency, and there are certain error, the present invention is by by the dummy node unit adjacent domain of current region
Calculate node replace, it is theoretical by the shape function in finite element, the exchange of node is realized by " inquiry-exchange ", that is, is inquired
To where dummy node target area, after object element, the dummy node list of current region is solved using shape function interpolation
The design parameter of member.For this method relative to conventional method, computational efficiency is higher, while reducing the error after interpolation to the greatest extent.
Embodiment
By taking Lishui is come down as an example, a kind of extensive Landslide Hazards Fast numerical simulation method, including it is following several
A step:
1, (1) obtains image data using fixed point flight using unmanned plane by investigating Lishui landslide areas, by
Smart3D generates the Lishui DEM landslide image and DSM image.As shown in Figure 1, wherein (a) is Lishui landslide morphology digital elevation
(DEM) image (b) is Lishui landslide areas numerical cutting tool (DSM) image.
(2) it chooses wherein one section of landslide and carries out quantitative simulation calculating, while the DEM using Lishui landslide before sliding and after sliding,
Raster symbol-base is carried out using Arcgis, to obtain the landslide source area range and elevation.
Specific formula such as formula 6:
q2=(- 0.00247* (t-450)2+500.4)/6
H=0.4885*q2 0.6
Formula 6
Wherein, q2The momentum in the direction x speed is represented, t represents current time step, and h represents mud-rock flow source area elevation.
(3) measuring density of material by corresponding physical and mechanical experiment is 1000g/cm3, using coulomb model, wherein in
Poly- power is 10000, and Basement surge 0.35 does not consider interstitial hydraulic pressure.
2, more than 30 ten thousand steres are measured by Lishui landslide side, larger, therefore the region division is carried out at 25 zonules
It calculates.
3, to zoning grid thickness and structured grid, to zoning material resource amount be more than 50% can be by grid
Constantly refinement two-stage, zoning have material resource but material resource amount less than 50% by mesh refinement level-one, no material resource and do not need
The region of calculating is roughened two-stage.The thick tessellated mesh of dynamic simultaneously, i.e. guarantee grid can be flowed according to region material resource amount etc. change into
Mobile state thickness changes with the variation of calculating.
4, the above results are subjected to numerical simulation to earth's surface disaster dynamic process using numerical simulation softwares such as massflow
It calculates.
Wherein, massflow (i.e. surficial process dynamic numerical simulation software) is a earth's surface dynamic process numerical simulation
Software is that the exploitation of research team, the Chinese Academy of Sciences is completed, and pacifies a of Technology Co., Ltd.'s sale of preventing and reducing natural disasters by Chengdu mountainous region ring
Commercial software.
It is primary every mono- Time step output of 2s, the calculated result of 25 zonings of output output utilizes
Tecplot is merged into a zoning output, and some numerical results after being calculated by numerical simulation software are as shown in Figure 2.
Above-described embodiment, by dividing to zoning, the region different to material resource ratio is using different grades of
Thick tessellated mesh pays close attention to region refinement, other area grid roughening.A length of 12s when entire calculating, and utilize traditional number
It is 25s or so that value simulation (not having to region division and network), which calculates total duration, it is seen that has been obviously shortened calculating duration, has mentioned
High computation rate.Grid flows variation progress dynamic thicknessization adjustment according to region material resource amount simultaneously, pays close attention to material resource amount
More region, improves computational accuracy, can simulate extensive Landslide Hazards dynamical evolution process rapidly, thus to take precautions against natural calamities
Mitigation department provides faster more accurate data and supports.
The foregoing is merely the preferred embodiment of the present invention, are not intended to restrict the invention, for this field
For technical staff, the invention may be variously modified and varied.All within the spirits and principles of the present invention, made any
Modification, equivalent replacement, improvement etc., should all be included in the protection scope of the present invention.