A spatial reconstruction high-efficiency spectral element modeling method based on fracture strike

Abstract

The application discloses a kind of spatial reconstruction high-efficiency spectrum unit modeling methods based on fracture trend, comprising: in UTM coordinate system, the fault outcrop line coordinate and site coordinate of simulation area are determined;According to fault outcrop line coordinate, the initial latitude and longitude range of simulation area is determined, and then the initial topographic data of simulation area is obtained and projected into UTM coordinate system;In the initial latitude and longitude range of simulation area, according to fault outcrop line coordinate and site coordinate, the fracture surface sub-source distribution model is constructed, and then the topographic model and crust model of simulation area are constructed according to initial topographic data, and the spectrum unit model construction is completed.The method of the application saves computing resources, and the calculation result is extremely small with traditional method error, and can meet the demand of seismic motion simulation engineering.

Description

Technical Field

[0001] This invention belongs to the field of earthquake engineering technology, specifically relating to an efficient spectral unit modeling method for spatial reconstruction based on fault orientation. Background Technology

[0002] In seismic design of structures, one of the current mainstream research directions is physical-based direct simulation methods. Among them, the spectral element method has the advantage of fully considering various influencing factors such as the source rupture process, three-dimensional non-uniform crustal structure, complex terrain, and site effects. It simulates site ground motion based on the basic physical mechanism of wave propagation, which is naturally reasonable. In the calculation of the maximum credible ground motion of a site, since the required ground motion frequency range for engineering projects is often large (maximum frequency greater than 10Hz), the computational workload of spectral element modeling is often very large. Currently, to avoid the transmission problem of inclined boundaries, spectral element modeling generally adopts a cuboid model directly established based on the local coordinate system of UTM (Universal Transverse Mercator Grid System). To avoid the transmission problem of inclined boundaries, it does not consider the fault strike and the correlation between the fault and the site. For the simulation of the maximum credible ground motion of the site, it only focuses on the influence of the surrounding terrain, crustal structure, and fault seismogenesis on the site. The modeling range is only related to the geographical coordinates of the fault and the site, and is independent of its strike. The resulting simulation range is much larger than the actual area of ​​interest, resulting in low computational efficiency. Summary of the Invention

[0003] To address the aforementioned shortcomings in existing technologies, the efficient spectral element modeling method based on fracture orientation spatial reconstruction provided by this invention solves the problems of large required range, low computational efficiency, and complex inclined boundary transmission issues in traditional modeling methods, which result in high costs for earthquake motion simulation using the spectral element method.

[0004] To achieve the above-mentioned objectives, this invention provides a method for efficient spectral unit modeling based on fracture orientation spatial reconstruction, comprising the following steps:

[0005] S100. In the UTM coordinate system, determine the fault outcrop coordinates and site coordinates of the simulated area;

[0006] S200. Based on the fault outcrop line coordinates, determine the initial latitude and longitude range of the simulation area, and then obtain the initial topographic data of the simulation area and project it into the UTM coordinate system.

[0007] S300. Within the initial latitude and longitude range of the simulation area, construct a fault surface source distribution model based on the fault outcrop coordinates and site coordinates.

[0008] S400. Based on the source distribution model of the fracture surface, construct a terrain model of the simulated area according to the initial terrain data;

[0009] S500. Based on the construction of the terrain model, a crustal model is constructed, and then the spectral unit model is constructed.

[0010] Further, step S100 includes the following steps:

[0011] S101. Based on the geological exploration data and deep geophysical inversion data within the study area, determine the latitude and longitude coordinates of the fault outcrop line of the seismogenic fault.

[0012] S102. Determine the latitude and longitude coordinates of the site;

[0013] S103. Determine the corresponding UTM area code of the simulation area based on the latitude and longitude coordinates of the site;

[0014] S104. Based on the UTM area code of the simulated area, project the latitude and longitude coordinates of the starting point and ending point of the fault outcrop line, as well as the latitude and longitude coordinates of the site, into the UTM coordinate system.

[0015] Further, step S200 includes the following sub-steps:

[0016] S201. Determine the fault strike based on the coordinates of the fault outcrop line. ;

[0017] S202. Determine the fault dip angle based on geological exploration data and deep geophysical inversion data. This allows for the determination of the fault rupture length. and width ;

[0018] S203, According to the fault strike Fault dip angle Fault rupture length and width Determine the initial longitude range of the geographic data for the simulation area;

[0019] S204. Based on the determined initial latitude and longitude range, obtain the initial terrain data of the simulation area and project it into the UTM coordinate system.

[0020] Furthermore, in step S203, the initial longitude range of the geographic data [Lon] 01 Lon 02 ] and latitude range [Lat 01 ,Lat 02 ] is represented as:

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027] In the formula, ( , () represents the geographical coordinates of the middle of the fault outcrop line. and These represent the length and width extensions considering terrain effects, respectively. This is for redundancy.

[0028] Furthermore, in step S300, in the constructed fracture surface source distribution model, the first [missing information] in the fracture strike direction The first tendency direction Coordinates of each source for:

[0029]

[0030]

[0031]

[0032] in, The local coordinates of the apex point of the fracture surface are represented as follows:

[0033]

[0034]

[0035]

[0036] In the formula, ( , )express( The projected coordinates in the S region of the UTM coordinate system, () represents the site coordinates. This indicates the minimum elevation of the surface outcrop line. Indicates the interval of the subsource along the direction of orientation. This indicates the interval of the subsource along the directional direction.

[0037] Further, step S400 includes the following sub-steps:

[0038] S401. Perform Delaunay triangulation on the initial terrain data projected onto the UTM coordinate system;

[0039] S402. Based on the Delaunay triangulation results, calculate the horizontal coordinates of the topographic corner points in the simulated area;

[0040] S403. Construct a terrain model based on the horizontal coordinates of the terrain corner points and the accuracy of the initial terrain data.

[0041] Furthermore, in step S402, the horizontal coordinates of the terrain corner points in the simulated area include the horizontal coordinates of the southwest corner point of the terrain. and the horizontal coordinates of the northeast corner point ( ), which are respectively represented as:

[0042]

[0043]

[0044]

[0045]

[0046] In the formula, , These are the horizontal coordinates of the southwest corner of the topography, determined by the site topographic effect and the source distribution model of the rupture surface; , The horizontal coordinates of the northeast corner point of the terrain, determined by the site topographic effect and the source distribution model of the rupture surface, are respectively expressed as:

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055] In the formula, ( () represents the site coordinates. and These represent the length and width extensions, respectively, taking into account the terrain effects. For redundancy, The horizontal coordinates represent the first sub-source in the direction of the fracture strike and the first sub-source in the direction of the fracture dip.

[0056] Furthermore, in step S403, in the constructed terrain model, along Direction Individual and Direction The horizontal coordinates of each terrain grid point ( ) and its vertical elevation They are respectively:

[0057]

[0058]

[0059]

[0060] In the formula, This represents the accuracy of the terrain grid in the terrain model, compared to the accuracy of the initial terrain data. equal, This indicates the elevation of the three vertices of the Delaunay triangle containing the terrain grid point. These represent the distances from each point on the terrain grid to each vertex of the triangle. They represent The corresponding line segment is extended in the opposite direction to the distance of each side of the triangle.

[0061] Further, step S500 includes the following sub-steps:

[0062] S501. Construct an initial three-dimensional crustal model based on deep Earth inversion data and near-surface borehole data of the simulated area;

[0063] S502. Perform Delaunay triangulation on the initial three-dimensional crustal model;

[0064] S503. Determine the crustal grid for each layer based on the data accuracy of the initial three-dimensional crustal model;

[0065] S504. Based on the triangulation results, determine the physical property parameters of each crustal grid layer;

[0066] S505. Based on the terrain model construction method, determine the crustal data in each crustal grid, construct the crustal model, and complete the spectral unit model construction.

[0067] The beneficial effects of this invention are as follows:

[0068] (1) The method of the present invention reconstructs the space of the simulation area, and the simulation area is basically parallel to the fault surface trace. Therefore, the simulation range is greatly reduced and more computing resources are saved.

[0069] (2) The method of the present invention avoids the complex problem of transmission at inclined boundaries. Although the resource requirements for calculation are reduced by nearly four times, the calculation results have very small errors compared with the traditional method, which can meet the needs of earthquake motion simulation engineering. Attached Figure Description

[0070] Figure 1 The flowchart of the efficient spectral unit modeling method based on fracture orientation for spatial reconstruction provided by this invention is shown.

[0071] Figure 2 The invention provides the initial latitude and longitude range of the determined geographical data and the terrain parameters within the simulated area.

[0072] Figure 3 This is a schematic diagram of the initial terrain data partitioning using Delaunay triangulation, provided for the present invention.

[0073] Figure 4 This is a schematic diagram of the Delaunay triangle provided by the present invention.

[0074] Figure 5 This is a schematic diagram of the overall skewness of the spectral unit provided by the present invention.

[0075] Figure 6 A schematic diagram showing the computational grid required for the conventional method provided by this invention and its relative relationship with the site and the seismic source rupture surface.

[0076] Figure 7 A schematic diagram showing the computational grid required for the method provided by this invention and its relative relationship with the site and the seismic source rupture surface.

[0077] Figure 8 A schematic diagram comparing the three-component ground motion simulated by the method provided by this invention with that obtained by a conventional method. Detailed Implementation

[0078] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0079] This invention provides an efficient spectral unit modeling method based on fracture orientation spatial reconstruction, such as... Figure 1 As shown, it includes the following steps:

[0080] S100. In the UTM coordinate system, determine the fault outcrop coordinates and site coordinates of the simulated area;

[0081] S200. Based on the fault outcrop line coordinates, determine the initial latitude and longitude range of the simulation area, and then obtain the initial topographic data of the simulation area and project it into the UTM coordinate system.

[0082] S300. Within the initial latitude and longitude range of the simulation area, construct a fault surface source distribution model based on the fault outcrop coordinates and site coordinates.

[0083] S400. Based on the source distribution model of the fracture surface, construct a terrain model of the simulated area according to the initial terrain data;

[0084] S500. Based on the construction of the terrain model, a crustal model is constructed, and then the spectral unit model is constructed.

[0085] Step S100 of this embodiment of the invention includes the following steps:

[0086] S101. Based on the geological exploration data and deep geophysical inversion data within the study area, determine the latitude and longitude coordinates of the fault outcrop line of the seismogenic fault.

[0087] Specifically, based on geological exploration data and deep geophysical inversion data, the coordinates of the fault exposure line are determined. The least squares method is used to fit the fault exposure line into a straight line segment, and its starting and ending latitude and longitude coordinates are expressed as follows: (…). , )and( , ).

[0088] S102. Determine the latitude and longitude coordinates of the site. ;

[0089] S103. Determine the corresponding UTM area code of the simulation area based on the latitude and longitude coordinates of the site;

[0090] S104. Based on the simulated region UTM area code The latitude and longitude coordinates of the starting point and ending point of the fault outcrop, as well as the latitude and longitude coordinates of the site, are projected into the UTM coordinate system.

[0091] Specifically, the local coordinates of the starting and ending points of the projected fault outcrop line are as follows: )and( The local coordinates of the site are ( ); ).

[0092] Step S200 of this embodiment of the invention includes the following sub-steps:

[0093] S201. Determine the fault strike based on the coordinates of the fault outcrop line. ;

[0094] Among them, the fault strike The calculation formula is:

[0095]

[0096] In the formula, The range of values ​​for is ( , ];

[0097] S202. Determine the fault dip angle based on geological exploration data and deep geophysical inversion data. This allows for the determination of the fault rupture length. and width ;

[0098] Specifically, in determining the fault dip angle Based on the magnitude of the earthquake ,inclination And the focal rupture mechanism, determining the fault rupture length based on empirical scaling relationships. and width ;

[0099] S203, According to the fault strike Fault dip angle Fault rupture length and width Determine the initial longitude range of the geographic data for the simulation area;

[0100] Among them, the initial longitude range of the geographic data [Lon] 01 Lon 02 ] and latitude range [Lat 01 ,Lat 02 ] is represented as:

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107] In the formula, ( , () represents the geographical coordinates of the middle of the fault outcrop line. and These represent the length and width extensions considering terrain effects, respectively. This is for redundancy; the geographical coordinates of the middle of the fault outcrop line are:

[0108]

[0109]

[0110] S204. Based on the determined initial latitude and longitude range, obtain the initial terrain data of the simulation area and project it into the UTM coordinate system.

[0111] In a specific example of the present invention, Figure 2 The paper presents the initial terrain parameters of the simulated area obtained based on the initial latitude and longitude range, including terrain data and crustal velocity density structure data.

[0112] In step S300 of this embodiment of the invention, in the constructed fracture surface source distribution model, the first [missing information] in the fracture orientation direction The first tendency direction Coordinates of each source for:

[0113]

[0114]

[0115]

[0116] in, The local coordinates of the apex point of the fracture surface are represented by the coordinates and orientation of the midpoint of the fracture outcrop line. To conserve computational resources to the greatest extent possible, a fracture surface parallel to the Y-axis of the UTM coordinate system is constructed with the site as the center. The resulting local coordinates of the apex point of the fracture surface used for simulation are expressed as follows:

[0117]

[0118]

[0119]

[0120] In the formula, ( , )express( The projected coordinates in the S region of the UTM coordinate system, () represents the site coordinates. This indicates the minimum elevation of the surface outcrop line. Indicates the interval of the subsource along the direction of orientation. This indicates the interval of the subsource along the directional direction.

[0121] Step S400 of this embodiment of the invention includes the following sub-steps:

[0122] S401. Perform Delaunay triangulation on the initial terrain data projected onto the UTM coordinate system;

[0123] Specifically, the initial terrain data is usually regular latitude and longitude grid data or scattered data, but it is no longer regular after being projected into the UTM coordinate system. Therefore, Delaunay triangulation is needed to subdivide the initial terrain data projected into the UTM coordinate system, such as... Figure 3 As shown;

[0124] S402. Based on the Delaunay triangulation results, calculate the horizontal coordinates of the topographic corner points in the simulated area;

[0125] The horizontal coordinates of the terrain corner points in the simulated area include the horizontal coordinates of the southwest corner point. and the horizontal coordinates of the northeast corner point ( ), which are respectively represented as:

[0126]

[0127]

[0128]

[0129]

[0130] In the formula, , These are the horizontal coordinates of the southwest corner of the topography, determined by the site topographic effect and the source distribution model of the rupture surface; , The horizontal coordinates of the northeast corner point of the terrain, determined by the site topographic effect and the source distribution model of the rupture surface, are respectively expressed as:

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138]

[0139] In the formula, ( () represents the site coordinates. and These represent the length and width extensions, respectively, taking into account the terrain effects. For redundancy, The horizontal coordinates of the first sub-source in the strike direction and the first sub-source in the dip direction are indicated.

[0140] S403. Construct a terrain model based on the horizontal coordinates of the terrain corner points and the accuracy of the initial terrain data;

[0141] Specifically, in the constructed terrain model, along Direction Individual and Direction The horizontal coordinates of each terrain grid point ( ) and its vertical elevation They are respectively:

[0142]

[0143]

[0144]

[0145] In the formula, This represents the accuracy of the terrain grid in the terrain model, compared to the accuracy of the initial terrain data. equal, This indicates the elevation of the three vertices of the Delaunay triangle containing the terrain grid point. These represent the distances from each point on the terrain grid to each vertex of the triangle. They represent The corresponding line segment is extended in the opposite direction to the distance of each side of the triangle.

[0146] In a specific example of the present invention, such as Figure 4 The above is given in the middle. and Representation in the Delaunay triangle.

[0147] Step S500 of this embodiment of the invention includes the following sub-steps:

[0148] S501. Construct an initial three-dimensional crustal model based on deep Earth inversion data and near-surface borehole data of the simulated area;

[0149] S502. Perform Delaunay triangulation on the initial three-dimensional crustal model;

[0150] Specifically, the initial crustal data in the initial three-dimensional crustal model is usually a regular three-dimensional latitude, longitude, and elevation grid point data; the horizontal coordinate points of the initial crustal model projected onto the UTM coordinate system are subdivided in the same way as the terrain data;

[0151] S503. Determine the crustal grid for each layer based on the data accuracy of the initial three-dimensional crustal model;

[0152] Specifically, the method for determining crustal grids is the same as that for topographic grids;

[0153] S504. Based on the triangulation results, determine the physical property parameters of each crustal grid layer;

[0154] Specifically, the values ​​of each physical property parameter (density, P-wave and S-wave velocity, attenuation coefficient) of each crustal grid can be determined by interpolation based on the distance to the vertex of the Delaunay triangle where the grid point is located.

[0155] S505. Based on the terrain model construction method, determine the crustal data in each crustal grid, construct the crustal model, and complete the spectral unit model construction.

[0156] In embodiments of the present invention, such as Figure 5 As shown, the simulation range required for the spectral unit model obtained using the method of this invention is given. If the exact same simulation frequency and grid size are used, the computational grid required by the traditional method and its relative relationship with the site and the source rupture surface are as follows. Figure 6 As shown, the computational model has a total of 8,025,666 degrees of freedom; the computational grid required by the method of this invention and its relative relationship with the site and the seismic source rupture surface are as follows. Figure 7 As shown, the computational model has a total of 2,019,612 degrees of freedom. Therefore, the computational cost required by the traditional method is 3.97 times that of the method of this invention. The spectral unit model obtained by the method of this invention saves more computational resources compared to the traditional method.

[0157] In an embodiment of the present invention, Figure 8 A comparison of three-component ground motion simulations obtained using the method of this invention and conventional methods is presented. It can be seen that, by avoiding the complex problem of transmission through tilted boundaries, although the computational resource requirements of the method of this invention are reduced by nearly four times, the calculation results have minimal error compared to the conventional method, and can meet the needs of ground motion simulation engineering.

[0158] Specific embodiments have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

[0159] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A spatially reconstructed high-efficiency spectral cell modeling method based on fracture strike, characterized in that, Includes the following steps: S100. In the UTM coordinate system, determine the fault outcrop coordinates and site coordinates of the simulated area; S200. Based on the fault outcrop line coordinates, determine the initial latitude and longitude range of the simulation area, and then obtain the initial topographic data of the simulation area and project it into the UTM coordinate system. S300. Within the initial latitude and longitude range of the simulation area, construct a fault surface source distribution model based on the fault outcrop coordinates and site coordinates. S400. Based on the source distribution model of the fracture surface, construct a terrain model of the simulated area according to the initial terrain data; S500. Based on the construction of the terrain model, a crustal model is constructed, and then the spectral unit model is constructed. Step S200 includes the following sub-steps: S201、According to the fault outcrop line coordinates to determine the fault strike ; S202. Determine the fault dip angle based on geological exploration data and deep geophysical inversion data. This allows for the determination of the fault rupture length. and width ; S203, According to the fault strike Fault dip angle Fault rupture length and width Determine the initial longitude range of the geographic data for the simulation area; S204. Based on the determined initial latitude and longitude range, obtain the initial terrain data of the simulation area and project it into the UTM coordinate system; In the step S203, the geographical data initial longitude range [Lon 01 , Lon 02 ] and latitude range [Lat 01 ,Lat 02 ] are represented as: In the formula, ( , () represents the geographical coordinates of the middle of the fault outcrop line. and These represent the length and width extensions considering terrain effects, respectively. This is for redundancy; In step S300, in the constructed fracture surface source distribution model, the first [missing information] in the fracture strike direction The first tendency direction Coordinates of each source for: in, The local coordinates of the apex point of the fracture surface are represented as follows: In the formula, ( , )express( The projected coordinates in the S region of the UTM coordinate system, () represents the site coordinates. This indicates the minimum elevation of the surface outcrop line. Indicates the interval of the subsource along the direction of orientation. This indicates the interval of the subsource along the directional direction.

2. The efficient spectral unit modeling method based on fracture orientation spatial reconstruction according to claim 1, characterized in that, Step S100 includes the following steps: S101. Based on the geological exploration data and deep geophysical inversion data within the study area, determine the latitude and longitude coordinates of the fault outcrop line of the seismogenic fault. S102. Determine the latitude and longitude coordinates of the site; S103. Determine the corresponding UTM area code of the simulation area based on the latitude and longitude coordinates of the site; S104. Based on the UTM area code of the simulated area, project the latitude and longitude coordinates of the starting point and ending point of the fault outcrop line, as well as the latitude and longitude coordinates of the site, into the UTM coordinate system.

3. The efficient spectral unit modeling method based on fracture orientation spatial reconstruction according to claim 1, characterized in that, Step S400 includes the following sub-steps: S401. Perform Delaunay triangulation on the initial terrain data projected onto the UTM coordinate system; S402. Based on the Delaunay triangulation results, calculate the horizontal coordinates of the topographic corner points in the simulated area; S403. Construct a terrain model based on the horizontal coordinates of the terrain corner points and the accuracy of the initial terrain data.

4. The efficient spectral unit modeling method based on fracture orientation spatial reconstruction according to claim 3, characterized in that, In step S402, the horizontal coordinates of the terrain corner points in the simulated area include the horizontal coordinates of the southwest corner point of the terrain. and the horizontal coordinates of the northeast corner point ( ), which are respectively represented as: In the formula, , These are the horizontal coordinates of the southwest corner of the topography, determined by the site topographic effect and the source distribution model of the rupture surface; , The horizontal coordinates of the northeast corner point of the terrain, determined by the site topographic effect and the source distribution model of the rupture surface, are respectively expressed as: In the formula, ( () represents the site coordinates. and These represent the length and width extensions, respectively, taking into account the terrain effects. For redundancy, The horizontal coordinates represent the first sub-source in the direction of the fracture strike and the first sub-source in the direction of the fracture dip.

5. The efficient spectral unit modeling method based on fracture orientation spatial reconstruction according to claim 3, characterized in that, In step S403, in the constructed terrain model, along Direction One and Direction The horizontal coordinates of each terrain grid point ( ) and its vertical elevation They are respectively: In the formula, This represents the accuracy of the terrain grid in the terrain model, compared to the accuracy of the initial terrain data. equal, This indicates the elevation of the three vertices of the Delaunay triangle containing the terrain grid point. These represent the distances from each point on the terrain grid to each vertex of the triangle. They represent The corresponding line segment is extended in the opposite direction to the distance of each side of the triangle.

6. The efficient spectral unit modeling method based on fracture orientation spatial reconstruction according to claim 1, characterized in that, Step S500 includes the following sub-steps: S501. Construct an initial three-dimensional crustal model based on deep Earth inversion data and near-surface borehole data of the simulated area; S502. Perform Delaunay triangulation on the initial three-dimensional crustal model; S503. Determine the crustal grid for each layer based on the data accuracy of the initial three-dimensional crustal model; S504. Based on the triangulation results, determine the physical property parameters of each crustal grid layer; S505. Based on the terrain model construction method, determine the crustal data in each crustal grid, construct the crustal model, and complete the spectral unit model construction.

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