Three-dimensional modeling method for long and large tunnel engineering based on fusion of ellipsoidal system and Cartesian coordinate system

Abstract

The present invention relates to a three-dimensional modeling method for a long tunnel project that integrates an ellipsoid system and a Cartesian coordinate system, comprising the following steps: 1) terrain modeling and three-dimensional line selection are performed on the ellipsoid system; 2) a series of tunnel section positioning points are created based on a 5m or 10m spacing using the three-dimensional line as a skeleton; 3) a local Cartesian coordinate system is established based on the positioning points; 4) a tunnel cross section is created under the local coordinate system; 5) a tunnel three-dimensional model is created and assembled using the three-dimensional line under the ellipsoid system as a skeleton. The present invention realizes modeling under a unified ellipsoid system without the need for conversion between the ellipsoid system and the Cartesian coordinate system, thus avoiding the problems of projection coordinate system mutation, data set breakage, and increased projection error caused by projection band change, and at the same time, this also helps to reduce model conversion and assembly steps and improve modeling efficiency.

Description

Technical Field

[0001] The present invention is a technology for three-dimensional modeling of long and large tunnel projects, specifically a three-dimensional modeling method integrating an ellipsoid system and a Cartesian coordinate system. Background Art

[0002] 3D modeling technology has been widely used in long and large tunnel projects. Through 3D modeling, engineers can better understand and plan road projects, improve project design and construction efficiency, reduce project costs and risks, improve project delivery quality, and promote multidisciplinary collaboration. 3D modeling can also help engineers quickly generate multiple design plans, compare and evaluate them, provide guidance for the construction process, and reduce errors and waste. In addition, 3D modeling can also identify potential problems and risks during the design and construction process, make adjustments and optimizations as early as possible, and improve the overall level of the project;

[0003] In the 3D modeling of long and large tunnel projects, the ellipsoid shape of the earth has an important influence on the modeling results. Ignoring the ellipsoid shape of the earth may cause deviations of buildings on the earth's surface, which in turn may cause safety hazards and other problems. Therefore, in the 3D modeling of long and large tunnel projects, the ellipsoid system or Cartesian coordinate system is selected for modeling according to professional needs. In the process of multi-professional collaborative modeling, it is necessary to convert the data of the ellipsoid coordinate system into the Cartesian coordinate system for 3D modeling, and convert the modeling results back to the ellipsoid coordinate system;

[0004] The existing multi-disciplinary collaborative 3D modeling of long and large tunnel projects adopts the following steps: T1, establish a terrain model in the ellipsoid system and perform 3D line selection; T2, select appropriate projection methods and projection bands according to the geographical location and accuracy requirements of the project, and divide the long and large tunnel project into many small ellipsoid bands on the ellipsoid system; T3, project the terrain and lines on the ellipsoid bands to the Cartesian coordinate system respectively; T4, the tunnel professional establishes a tunnel professional 3D model based on the terrain and line 3D models on the projected Cartesian coordinate system; T5, convert the 3D model of the tunnel professional Cartesian coordinate system into a 3D model in the ellipsoid coordinate system to achieve 3D model integration. In the process of mutual conversion between the ellipsoid system and the Cartesian coordinate system, since the two coordinate systems are essentially different, the error caused by the projection band change increases with the selected projection latitude bandwidth and the distance to the projection center latitude line. Especially at the edge of the projection band change, there will be a problem of inaccurate position of the 3D elements crossing the band change boundary due to the sudden change of the projection coordinate system, which usually requires manual adjustment or secondary projection band change method to solve. In order to more conveniently realize the 3D modeling requirements of long and large tunnel projects, it is necessary to invent and innovate the 3D modeling method that integrates the ellipsoid system and the Cartesian coordinate system. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a three-dimensional modeling method integrating ellipsoid system and Cartesian coordinates for long tunnel projects, so as to meet the three-dimensional modeling requirements of long tunnel projects under the ellipsoid system;

[0006] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0007] The three-dimensional modeling method of a long tunnel engineering by integrating the ellipsoid system and the Cartesian coordinate system of the present invention is carried out according to the following steps:

[0008] 1) Terrain modeling and 3D line selection on the ellipsoid system;

[0009] 1-1) Terrain modeling includes three steps: terrain data acquisition, data import and model creation. The terrain elevation data can be satellite data or laser radar scanning data. The data is imported into the ellipsoid system, and the terrain modeling is completed by triangular patch fitting on the ellipsoid system.

[0010] 1-2) Using the intersection method to select the line on the ellipsoid system, the horizontal curve and the vertical curve of the line are selected respectively, and the two are spatially coupled to form a three-dimensional line;

[0011] 2) Using the 3D line as the framework, create a series of tunnel section positioning points at 5m or 10m intervals on the 3D line according to the starting and ending mileage of the tunnel;

[0012] 3) Create local Cartesian coordinates. The specific method is:

[0013] 3-1) According to the coordinate points of the tunnel section created in step 2), the tangent of the three-dimensional line is obtained, and the x' coordinate axis is established with the line forward direction as the positive direction;

[0014] 3-2) According to the tunnel section coordinate points created in step 2), a z coordinate axis is established based on the out-of-plane normal direction of the reference ellipsoid surface;

[0015] 3-3) Using the z-axis of step 3-2) and the x' axis established in step 3-1), establish the y-axis according to the right-hand rule z-x';

[0016] 3-4) The y-axis of step 3-3) and the z-axis established in step 3-2) are used to establish the x-axis according to the right-hand rule to form an xyz Cartesian coordinate system, thus completing the creation of the local Cartesian coordinate system of the tunnel section;

[0017] 4) In the local Cartesian coordinate system of a series of tunnel sections established in step 3), a sketch is created in the yz plane, and a series of tunnel cross sections are created using arcs and polylines, including: tunnel outline, primary support, secondary lining, invert, drainage ditch, etc.;

[0018] 5) Using the 3D line as the skeleton, using a series of tunnel cross sections created in step 4), starting from the tunnel starting mileage, two adjacent cross sections are grouped together, and a 3D model of the segmented tunnel is established by using a scanning or multi-section fitting method, and then assembled into a complete 3D model of the tunnel;

[0019] The beneficial effects of the present invention are mainly reflected in the following aspects:

[0020] 1. The terrain and line models are both established in the ellipsoid system, and there is no need to convert between the ellipsoid system and the Cartesian coordinate system, which reduces the problems of projection coordinate system mutation, data set breakage and increased projection error caused by projection zone change in terrain and line models;

[0021] 2. According to the interval of 5m or 10m of the horizontal curve, the local coordinates of the tunnel section created on the three-dimensional line are accurate coordinates in the ellipsoid system. The three-dimensional model of the tunnel formed with the three-dimensional line in the ellipsoid system as the skeleton is also accurate;

[0022] 3. The three-dimensional modeling process is carried out under the ellipsoid system, which reduces the steps of model conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] This specification includes the following five drawings:

[0024] Figure 1 It is a flow chart of 3D modeling of existing long and large tunnel projects;

[0025] Figure 2 It is a flow chart of three-dimensional modeling of long tunnel engineering by integrating ellipsoid system and Cartesian coordinate system of the present invention;

[0026] Figure 3 It is a schematic diagram of the definition of the local Cartesian coordinate system under the ellipsoid system;

[0027] Figure 4 It is a schematic diagram of tunnel cross section created under the ellipsoid system;

[0028] Figure 5 It is a schematic diagram of three-dimensional modeling of tunnel under the ellipsoid system. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0030] Reference Figure 2 , the three-dimensional modeling method of long and large tunnel engineering by integrating ellipsoid system and Cartesian coordinate system of the present invention;

[0031] The implementation method of the present invention is to perform terrain modeling and three-dimensional line selection in an ellipsoid system, take the three-dimensional line as the skeleton, establish a series of tunnel section Cartesian local coordinate systems on the three-dimensional line at a specified interval on the flat curve, establish the tunnel section on this local coordinate system, and assemble to form a three-dimensional tunnel model through three-dimensional geometric modeling, according to the following steps:

[0032] S1, terrain modeling and 3D line selection on the ellipsoid system;

[0033] S1-1, terrain modeling includes three steps: terrain data acquisition, data import and model creation. The terrain elevation data can be satellite data or laser radar scanning data. The data is imported into the ellipsoid system, and the terrain modeling is completed by triangular patch fitting on the ellipsoid system.

[0034] S1-2, using the intersection method to select the line on the ellipsoid system, select the horizontal curve and the vertical curve of the line respectively, and the two are spatially coupled to form a three-dimensional line;

[0035] S2, using the 3D line as the skeleton, creates a series of tunnel section positioning points on the 3D line at intervals of 5m or 10m according to the starting and ending mileage of the tunnel;

[0036] S3, create local Cartesian coordinates, the specific method is:

[0037] S3-1, according to the coordinate points of the tunnel section created in step S2, obtain the tangent of the three-dimensional line, and establish the x' coordinate axis with the forward direction of the line as the positive direction;

[0038] S3-2, according to the tunnel section coordinate points created in step S2, a z coordinate axis is established based on the out-of-plane normal direction of the reference ellipsoid surface;

[0039] S3-3, using the z-axis of step S3-2 and the x'-axis established in step S3-1 to establish the y-axis according to the right-hand rule z-x';

[0040] S3-4, using the y-axis of step S3-3 and the z-axis established in step S3-2, according to the right-hand rule, yz establishes the x-axis to form an xyz Cartesian coordinate system, and the local Cartesian coordinate system of the tunnel section is created;

[0041] S4, in the local Cartesian coordinate system of a series of tunnel sections established in step S3, a sketch is established in the yz plane, and a series of tunnel cross sections are created by combining arcs and polylines, including: tunnel profile, primary support, secondary lining, invert, drainage ditch, etc.;

[0042] S5, using the three-dimensional line as the skeleton, using a series of tunnel cross sections created in step S4, starting from the tunnel starting mileage, two adjacent cross sections as a group, using a scanning or multi-section fitting method, to establish a segmented tunnel three-dimensional model, and assemble to form a complete tunnel three-dimensional model;

[0043] In step S2, the spacing of the tunnel section positioning points is 5m or 10m;

[0044] In step S4, the spacing of tunnel sections in the local Cartesian coordinate system is 5m or 10m.

Claims

1. A three-dimensional modeling method for long tunnel engineering by integrating ellipsoidal system and Cartesian coordinate system, characterized in that: The following steps are involved: 1) Terrain modeling and 3D line selection on the ellipsoid system; 1-1) Terrain modeling includes three steps: terrain data acquisition, data import and model creation. The terrain elevation data uses satellite data or laser radar scanning data, which is imported into the ellipsoid system. The terrain modeling is completed by triangular patch fitting on the ellipsoid system. 1-2) Using the intersection method to select the line on the ellipsoid system, the horizontal curve and the vertical curve of the line are selected respectively, and the two are spatially coupled to form a three-dimensional line; 2) Using the 3D line as the framework, create a series of tunnel section positioning points at 5m or 10m intervals on the 3D line according to the starting and ending mileage of the tunnel; 3) Create local Cartesian coordinates. The specific method is: 3-1) According to the tunnel section coordinate points created in step 2), the tangent of the three-dimensional line is obtained, and the x' coordinate axis is established with the line forward direction as the positive direction; 3-2) according to the tunnel section coordinate points created in step 2), a z coordinate axis is established based on the out-of-plane normal direction of the reference ellipsoid surface; 3-3) Using the z-axis of step 3-2) and the x'-axis established in step 3-1), establish the y-axis according to the right-hand rule z-x'; 3-4) The y-axis of step 3-3) and the z-axis established in step 3-2) are used to establish the x-axis according to the right-hand rule to form an xyz Cartesian coordinate system, thus completing the creation of the local Cartesian coordinate system of the tunnel section; 4) In the local Cartesian coordinate system of a series of tunnel sections established in step 3), a sketch is established in the yz plane, and a series of tunnel cross sections are created by combining arcs and polylines, including: tunnel outline, primary support, secondary lining, invert, and drainage ditch; 5) Using the three-dimensional line as the skeleton, using a series of tunnel cross sections created in step 4), starting from the starting mileage of the tunnel, two adjacent cross sections are grouped together, and a scanning or multi-section fitting method is used to establish a segmented tunnel three-dimensional model, which is assembled into a complete tunnel three-dimensional model.

2. The three-dimensional modeling method for long tunnel engineering by integrating the ellipsoidal system and the Cartesian coordinate system as claimed in claim 1 is characterized in that: In the step 2), the spacing between the tunnel section positioning points is 5m or 10m.

3. The three-dimensional modeling method for long tunnel engineering by integrating the ellipsoidal system and the Cartesian coordinate system as claimed in claim 1 is characterized in that: In the step 4), the spacing of the tunnel sections in the local Cartesian coordinate system is 5m or 10m.

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