Roadway three-dimensional modeling method and system based on actually measured boundary line and elevation point

Abstract

The invention relates to the technical field of mine underground engineering digital modeling, and discloses a roadway three-dimensional modeling method based on actual measurement boundary lines and elevation points, which comprises the following steps: S1, data preparation: importing an underground roadway actual measurement CAD drawing through a CAD file analysis function; s2, layering the roadway; s3, determining a three-dimensional surface of the bottom of the roadway: selecting a boundary line subset in any line layer in the step S2; and S5, combining roadway models. Three types of core data including roadway actual measurement boundary lines, elevation points and geological attributes are extracted from an actual measurement CAD drawing of an existing underground roadway of a mine, expensive equipment for laser scanning, drilling measurement and the like does not need to be additionally purchased, and the hardware input cost of digital modeling of small and medium-sized mines is effectively reduced; meanwhile, the data is stored in a unified mode through the shp format, the compatibility of the data and a GIS platform is guaranteed, a stable data basis is provided for the subsequent modeling process, and the method adapts to the current situation of existing data resources of a mine.

Description

Technical Field

[0001] This invention relates to the field of digital modeling technology for underground mining engineering, specifically to a method and system for three-dimensional modeling of tunnels based on measured boundary lines and elevation points. Background Technology

[0002] In the field of underground mining engineering, 3D modeling of tunnels is one of the core technologies for realizing digital management and intelligent operation of mines. Its core is to restore the spatial morphology of tunnels and the surrounding geological environment through digital means, providing accurate spatial data support for tunnel construction plan design, ventilation system optimization, safety risk monitoring and other work. It is a key foundation for the transformation of mines from traditional operation mode to intelligent operation.

[0003] In existing technologies, 3D modeling of tunnels mainly relies on two technical approaches: one is to acquire point cloud data based on laser scanning equipment, and then construct the tunnel model through point cloud denoising, registration, and modeling software; the other is to manually input parameters such as arch height, wall height, and tunnel width into the modeling software based on design drawings or manually measured cross-sectional parameters, and then generate a 3D model through operations such as stretching and lofting. Both approaches require specialized equipment or rely on human experience to complete key steps.

[0004] Existing 3D tunnel modeling technologies generally suffer from the problem of relying on high-cost equipment for data sources or requiring a large amount of manual parameter input during the modeling process. For small and medium-sized mines that only have measured CAD drawings of underground tunnels and lack high-priced equipment and professional modeling technicians, existing technologies are unable to meet their low-cost and low-tech modeling needs. This makes it difficult to advance the digital modeling of tunnels in these mines and prevents them from effectively relying on 3D models to carry out subsequent engineering management work. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method and system for three-dimensional tunnel modeling based on measured boundary lines and elevation points, solving the problem of tunnel modeling relying on high-cost data or manual parameters.

[0006] To achieve the above objectives, the present invention provides a three-dimensional tunnel modeling method based on measured boundary lines and elevation points, comprising the following steps: S1. Data Preparation: Import the measured CAD drawing of the underground tunnel using the CAD file parsing function, extract the measured boundary line layer and elevation point layer from the measured CAD drawing of the underground tunnel, and simultaneously extract the geological attribute layer associated with the measured CAD drawing of the underground tunnel. The geological attribute layer contains rock layer hardness, burial depth, and support type attribute information; save the measured boundary line layer of the tunnel as a first shapefile, the elevation point layer as a second shapefile, and the geological attribute layer as a third shapefile. S2, Tunnel Layering: Based on the spatial overlap relationship of the measured boundary lines of the tunnels, the tunnel branching logic, and the geological attribute partitioning of the third shapefile, the measured boundary lines of the tunnels in the first shapefile are processed into segmentation lines to obtain at least two non-spatial overlap subsets of boundary lines. Each subset of boundary lines is saved to a different line layer, and each line layer is associated with the corresponding geological attribute information. S3. Determine the three-dimensional surface of the tunnel bottom: Select a subset of boundary lines from any of the line layers mentioned in step S2. After topology checking, line creation area, elevation point filtering, contour line generation and adjustment, generate the corresponding three-dimensional surface of the tunnel bottom based on the adjusted contour lines and the subset of boundary lines. S4. Automatically construct the tunnel model: Triangulate the three-dimensional surface of the tunnel bottom obtained in step S3 to generate a bottom triangular mesh. Dynamically adjust the top surface parameters based on the geological attribute information of the corresponding line layer in the third shapefile. Then, construct a top triangular mesh based on the bottom triangular mesh and the adjusted top surface parameters. Simultaneously, extract the outer boundary lines of the bottom and top triangular meshes to construct a side triangular mesh. Stitch the bottom, top, and side triangular meshes together and apply texture to obtain a single-layered three-dimensional tunnel model. S5. Merge the tunnel models: For each of the remaining line layers in step S2, repeat steps S3 to S4 to obtain the single-layer tunnel 3D model corresponding to each line layer. After unifying the texture display parameters of all the single-layer tunnel 3D models, perform spatial stitching to obtain the overall tunnel 3D model.

[0007] Preferably, in step S1, the format of the measured CAD drawing of the underground tunnel is dwg or dxf, and the CAD file parsing function supports file parsing of AutoCAD 2007 and above; each elevation point in the elevation point layer is associated with an elevation value attribute, and the attribute information of the geological attribute layer comes from the geological annotation layer or attribute block data in the measured CAD drawing of the underground tunnel, and the boundary line vector is automatically associated with the corresponding geological attribute during the parsing process.

[0008] Preferably, in step S2, the geological attribute partitioning is based on the following criteria: hardness partitioning with a rock layer hardness of 30 MPa as the threshold, where rock layer hardness ≥ 30 MPa is one partition and rock layer hardness < 30 MPa is another partition; burial depth partitioning with a burial depth of 500 m as the threshold, where burial depth ≥ 500 m is one partition and burial depth < 500 m is another partition; branching and support partitioning according to support type, including anchor bolt support, masonry arch support, and anchor spraying support; different line layers include at least a black line layer and a green line layer, each line layer corresponds to an independent tunnel branch or a continuous tunnel segment without spatial overlap, and the boundary line subset of each line layer is associated with a unique identifier ID, which is mapped one-to-one with the geological attribute information in the third shapefile.

[0009] Preferably, in step S4, the rule for dynamically adjusting the top surface parameters based on geological attribute information is as follows: When the rock strata hardness associated with the corresponding line layer is ≥30MPa, the preset tunnel height h0 is adjusted to h. 0base ×1.1, adjust the arching parameter g at the top of the tunnel to g 0base ×0.8, where h 0base The initial preset tunnel height is 3m, g 0base The initial arching parameter is set to 0.3; when the burial depth associated with the corresponding line layer is ≥500m, the preset tunnel height h0 is adjusted to h. 0base ×1.2, adjust the arching parameter g at the top of the tunnel to g 0base ×0.7; When the support type associated with the corresponding line layer is masonry arch support, adjust the preset roadway height h0 to h 0base ×1.05, the arching parameter g remains g 0base constant.

[0010] Preferably, in step S3, the topology check includes checking the closure of the boundary lines, checking the unbroken state of the boundary lines, and checking the non-self-intersection of the boundary lines; the elevation point filtering is based on the roadway boundary area vector surface generated by the line-based area, and filters the target elevation points in the second shapefile file that are located within the roadway boundary area vector surface; the contour line generation adopts the Kriging interpolation method or the inverse distance weighted interpolation method; the contour line adjustment includes regenerating contour lines after identifying and removing abnormal elevation points by the standard deviation method, and adjusting the spatial position of the contour lines by the moving point function on the line.

[0011] A 3D tunnel modeling system based on measured boundary lines and elevation points includes a GIS platform and the following functional modules integrated into the GIS platform: The data import module is used to import measured CAD drawings of underground tunnels through the CAD file parsing function, extract the measured boundary line layer, elevation point layer, and associated geological attribute layer of the tunnel. The geological attribute layer contains rock hardness, burial depth, and support type attribute information. The measured boundary line layer of the tunnel is saved as a first shapefile, the elevation point layer is saved as a second shapefile, and the geological attribute layer is saved as a third shapefile. The tunnel layering module is used to perform segmentation processing on the measured boundary lines of the tunnel in the first shapefile based on the spatial overlap relationship of the measured boundary lines of the tunnel, the tunnel branching logic, and the geological attribute partitioning of the third shapefile. This process yields at least two non-spatial overlap subsets of boundary lines, stores each subset of boundary lines in a different line layer, and associates each line layer with the corresponding geological attribute information. The bottom 3D surface construction module is used to select a subset of boundary lines in any of the line layers, and after topology checking, line creation area, elevation point filtering, contour line generation and adjustment, generate the corresponding bottom 3D surface of the tunnel based on the adjusted contour lines and the subset of boundary lines. The automatic model building module is used to triangulate the three-dimensional surface of the bottom of the tunnel to generate a bottom triangular mesh, dynamically adjust the top surface parameters based on the geological attribute information of the corresponding line layer in the third shapefile, construct a top triangular mesh based on the bottom triangular mesh and the adjusted top surface parameters, extract the outer boundary lines of the bottom and top triangular meshes to construct a side triangular mesh, and stitch the bottom, top, and side triangular meshes together and apply texture to obtain a single-layer tunnel three-dimensional model. The model merging module is used to obtain the corresponding single-layer tunnel 3D model for each of the remaining line layers through the bottom 3D surface construction module and the automatic model construction module. After unifying the texture display parameters of all the single-layer tunnel 3D models, the modules are spatially stitched together to obtain the overall tunnel 3D model.

[0012] Preferably, the data import module is also used to perform vector data cleaning on the imported measured CAD drawings of underground tunnels. The vector data cleaning includes deleting redundant auxiliary drawing elements and repairing fractured boundary line vectors. The redundant auxiliary drawing elements include annotation lines and legend blocks. During the cleaning process, the attribute association relationship of the geological attribute layer is preserved to ensure the integrity of the mapping between the boundary line vector and the rock layer hardness, burial depth, and support type information.

[0013] Preferably, the automatic model construction module includes a triangulation densification unit, a top surface parameter adjustment unit, a top surface generation unit, a side surface generation unit, and a model stitching unit. The triangulation densification unit is used to set the mesh accuracy and perform triangulation processing on the three-dimensional surface of the tunnel bottom. The mesh accuracy is set to 0.5m to 2m, and the triangulation processing adopts the Delaunay triangulation algorithm. The top surface parameter adjustment unit is used to call the geological attribute information of the corresponding line layer in the third shapefile and dynamically adjust the top surface parameters h0 and g according to preset rules, which are consistent with the adjustment rules. The top surface generation unit is used to calculate the vertex movement height based on the adjusted h0 and g, combined with the nearest horizontal distance w from the vertex of the bottom triangulation to the boundary line, using the formula h=h0+pow(w,g), and adjust the vertex elevation to generate the tunnel top surface triangulation. The side surface generation unit is used to extract the outer boundary lines of the bottom and top triangulations and construct the side triangulations. The model stitching unit is used to stitch the bottom, top, and side triangulations according to the principle of coordinate consistency and assign an initial texture matching the support type.

[0014] Preferably, the bottom three-dimensional surface construction module includes a topology checking unit, a region filtering unit, an interpolation unit, an anomaly handling unit, and a three-dimensional surface generation unit; The topology checking unit is used to perform closure checks, no-breakpoint checks, and no-self-intersection checks on the boundary line subsets, and to perform line area creation processing on the boundary line subsets that pass the checks to generate the roadway boundary area vector surface. The zone filtering unit is used to filter target elevation points located within the zone in the second shapefile based on the vector surface of the lane boundary zone. The interpolation unit is used to interpolate the target elevation points using Kriging interpolation or inverse distance weighted interpolation to generate contour lines; The three-dimensional surface generation unit is used to generate a three-dimensional surface at the bottom of the tunnel based on the adjusted contour lines and corresponding boundary line subsets.

[0015] Preferably, the anomaly processing unit is used to identify and remove abnormal elevation points using the standard deviation method, and trigger the interpolation unit to regenerate contour lines; and / or, the anomaly processing unit supports adjusting the spatial position of contour lines by moving points on the line.

[0016] This invention provides a method and system for three-dimensional modeling of tunnels based on measured boundary lines and elevation points. It has the following beneficial effects: 1. This invention reuses existing underground roadway measured CAD drawings from mines to extract three core data types: measured roadway boundary lines, elevation points, and geological attributes. This eliminates the need to purchase expensive equipment such as laser scanning and borehole surveying, effectively reducing the hardware investment cost for digital modeling in small and medium-sized mines. At the same time, by storing data in a unified SHP format, it ensures data compatibility with GIS platforms, provides a stable data foundation for subsequent modeling processes, and adapts to the current status of existing data resources in mines.

[0017] 2. This invention achieves fully automated operation from data preparation to overall model generation through process design such as roadway layering, topology checking, automatic contour line generation, and triangular network modeling. It reduces manual intervention, avoids modeling deviations caused by manual parameter input, and improves the morphological restoration accuracy of the roadway 3D model. It is especially suitable for accurate modeling of complex structures such as roadway turns and intersections, ensuring the consistency between the model and the actual roadway.

[0018] 3. This invention integrates five major modules: data import, roadway layering, bottom 3D surface construction, automatic model construction and merging. Each module works in conjunction with geological attribute information. It can dynamically adjust modeling parameters according to rock layer hardness, burial depth and support type to adapt to roadway modeling needs under different geological conditions, enhance the scenario adaptability of the technical solution, and provide flexible data support for subsequent mine engineering planning and maintenance. Attached Figure Description

[0019] Figure 1 This is a flowchart of the present invention; Figure 2 This is a schematic diagram of the measured boundary line and elevation point coordinate data of the tunnel according to the present invention; Figure 3 This is a schematic diagram showing the layered display of the measured boundary lines of the tunnel according to the present invention; Figure 4 This is a schematic diagram showing the distribution of target elevation points at the bottom of the tunnel according to the present invention. Figure 5 This is a schematic diagram showing the superposition of contour lines and boundary lines at the bottom of the tunnel according to the present invention; Figure 6 This is a color scale diagram of the contour line elevation distribution of the present invention; Figure 7 This is a schematic diagram of the densification of the triangular mesh on the bottom surface of the tunnel according to the present invention; Figure 8 This is a diagram illustrating the outer boundary line of the bottom triangular mesh of the present invention. Figure 9 This is a schematic diagram of the arched triangular mesh on the top surface of the tunnel according to the present invention; Figure 10 This is a schematic diagram of the triangular mesh connection on the side of the tunnel according to the present invention; Figure 11This is a schematic diagram of a three-dimensional model (with texture) of a single-layer tunnel according to the present invention; Figure 12 This is a schematic diagram showing the independent display of the multi-layered tunnel three-dimensional model of the present invention; Figure 13 This is a schematic diagram showing the completed assembly of the overall three-dimensional tunnel model of the present invention. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1: Please see the appendix Figure 1-13 This invention provides a method for three-dimensional modeling of tunnels based on measured boundary lines and elevation points, specifically including the following steps: Step S1: Data Preparation Activate the CAD file parsing function to import the measured CAD drawings of underground tunnels provided by the mine. The CAD drawing format is dwg or dxf. The parsing function is compatible with AutoCAD 2007 and later versions, and can automatically identify and extract the three core layers in the drawing: The measured boundary line layer of the tunnel contains boundary vector information of the horizontal projection of the tunnel, covering the complete boundary outline of straight tunnel sections, turning sections, and intersection sections; Elevation point layer: Each elevation point is associated with a unique elevation value attribute, which is directly derived from the tunnel floor elevation data recorded during the actual measurement process, and can accurately reflect the vertical undulations of the tunnel floor. Geological attribute layer: Attribute information is extracted from the geological annotation layer or attribute block data of the CAD drawing, including three key parameters: rock layer hardness, burial depth, and support type. Rock layer hardness is the uniaxial compressive strength value of rock tested in the laboratory, burial depth is the vertical distance from the tunnel floor to the ground surface, and support type includes three common types: anchor bolt support, masonry arch support, and anchor spray support.

[0022] After extraction, the measured boundary line layer of the tunnel is saved as a first shapefile, the elevation point layer as a second shapefile, and the geological attribute layer as a third shapefile. Shapefile format was chosen because it is a common vector format for Geographic Information Systems (GIS), which can completely preserve the spatial topological relationships and attribute associations of the layers, providing a data foundation for subsequent layering and modeling.

[0023] Step S2: Channel layering Based on three criteria, the measured boundary lines of the tunnels in the first shapefile are processed into dividing lines: Spatial overlap relationship: When two or more boundary lines intersect or overlap on the horizontal projection, they are divided along the geometric intersection of the overlapping area to ensure that the subsets of boundary lines do not have spatial overlap after division; Roadway branching logic: For the branching structure formed by the intersection of roadways (such as "one main road and two branches" or "cross intersection"), the roadways are divided along the branch nodes so that each branch corresponds to an independent subset of boundary lines. Geological attribute zoning: Based on the geological attributes of the third-party SHP format file, the area is divided into zones. With rock hardness of 30MPa as the threshold, the area ≥30MPa is divided into hard rock zone and the area <30MPa is divided into soft rock zone. With burial depth of 500m as the threshold, the area ≥500m is divided into deep zone and the area <500m is divided into shallow zone. According to the support type, the area is divided into anchor bolt support zone, masonry arch support zone, and anchor spray support zone.

[0024] After segmentation, at least two subsets of boundary lines without spatial overlap are obtained, and each subset is saved to a different line layer. Each line layer contains at least a black line layer and a green line layer. The black line layer corresponds to main tunnel branches or long continuous tunnel segments, while the green line layer corresponds to auxiliary tunnel branches or short continuous tunnel segments. Each line layer is associated with a unique identifier ID, which maps one-to-one with the geological attribute information in the third-party shapefile, ensuring that the geological parameters of the corresponding area can be quickly retrieved during subsequent modeling.

[0025] Step S3: Determine the 3D surface of the tunnel bottom. Select a subset of the boundary lines of any line layer from Step S2, and generate the 3D surface of the tunnel bottom according to the following process: Topology check: Three checks are performed on the subset of boundary lines: closure check, ensuring the boundary lines form a complete closed profile with no open ends; no breakpoint check, ensuring the boundary line vectors are continuous and unbroken throughout the entire roadway segment; and no self-intersection check, ensuring the boundary lines have no redundant nodes formed by their own intersections. For boundary lines that fail the checks, breakpoints are automatically repaired or self-intersecting segments are deleted before re-checking until the topology requirements are met. Line creation zone: Perform the line creation zone operation on the subset of boundary lines that have passed the topology check. Generate a closed roadway boundary zone vector surface based on the spatial coordinates of the boundary lines. This vector surface accurately defines the horizontal range of the current roadway segment. Elevation point filtering: Using the vector plane of the roadway boundary area as a spatial constraint, the elevation points in the second shapefile are filtered, retaining only the target elevation points located within the vector plane and eliminating interfering elevation points outside the roadway range. Contour line generation: Kriging interpolation or inverse distance weighted interpolation is used to interpolate the target elevation points. Kriging interpolation, by constructing a semi-variogram model, considers the spatial correlation of elevation points and is suitable for tunnel sections with complex elevation changes. Inverse distance weighted interpolation, based on the principle that "closer distances have greater influence," calculates the distance weights between the target point and each elevation point to achieve interpolation, and is suitable for tunnel sections with gentle elevation changes. The choice between the two methods can be made according to the actual terrain of the tunnel, and the interpolation results generate continuous contour lines. Contour line adjustment: Abnormal elevation points are identified by the standard deviation method. The mean and standard deviation of the elevation values ​​of all target elevation points are calculated. Elevation points that exceed the mean ± 2 times the standard deviation are identified as abnormal points. After deleting the abnormal points, the interpolation is re-performed to generate contour lines. If there is a deviation between the spatial position of the contour lines and the actual shape of the roadway floor, the coordinates of the contour line nodes can be finely adjusted by moving the point on the line until the contour lines are consistent with the measured floor undulations. 3D surface generation: The adjusted contour lines are spatially superimposed with the subset of boundary lines in step S2. Based on the elevation information of the contour lines and the horizontal range of the boundary lines, the corresponding 3D surface of the tunnel bottom is constructed using the 3D surface generation function of the GIS platform. This 3D surface can completely restore the spatial morphology of the tunnel bottom.

[0026] Step S4: Automatically construct the tunnel model Base triangulation generation: Triangulation is performed on the three-dimensional surface of the tunnel bottom obtained in step S3. First, the mesh accuracy is set to 0.5m to 2m (the mesh accuracy can be adjusted according to the modeling accuracy requirements; the higher the accuracy, the denser the triangulation nodes). Then, the Delaunay triangulation algorithm is used for triangulation. This algorithm maximizes the minimum interior angle of the triangles, avoids generating narrow triangles, ensures the geometric stability of the base triangulation, and finally obtains a base triangulation that fits the shape of the tunnel bottom. Top surface parameter adjustment: The geological attribute information associated with the current line layer in the third shapefile is retrieved, and the top surface parameters are dynamically adjusted according to preset rules—the initial preset tunnel height h0 (denoted as h). 0base The initial arch height is 3m, and the initial arch height parameter is g (denoted as g). base The value is 0.3; if the rock layer hardness is ≥30MPa, h0 is adjusted to h. 0base ×1.1, g is adjusted to g base ×0.8; If the burial depth is ≥500m, adjust h0 to h 0base ×1.2, g is adjusted to g base ×0.7; If the support type is masonry arch support, adjust h0 to h 0base ×1.05, g maintains g base constant; Top triangulation generation: Copy the bottom triangulation as the base contour of the top triangulation. Calculate the nearest horizontal distance w from each vertex in the base contour to the corresponding subset of boundary lines. Calculate the moving height h of each vertex using the formula h=h0+pow(w,g) (pow is a power function). Adjust the elevation value of the vertex according to the moving height h, so that the vertex is raised vertically by the corresponding height, and finally form a top triangulation that is consistent with the actual arch structure of the tunnel. Side triangulation generation: Extract the outer boundary lines of the bottom triangulation and the top triangulation, and connect the corresponding nodes in the two outer boundary lines in sequence to construct a closed side triangulation. The height of the side triangulation is consistent with the elevation difference between the top and bottom triangulations, which can reflect the vertical height of the roadway. Model stitching and texture assignment: The bottom triangular mesh, top triangular mesh, and side triangular mesh are stitched together according to the principle of coordinate consistency to ensure seamless connection between the three in space; the initial texture is assigned according to the support type associated with the current line layer, the anchor bolt support is assigned a bitmap with anchor bolt arrangement texture, the masonry arch support is assigned a bitmap with concrete masonry arch texture, and the shotcrete support is assigned a bitmap with shotcrete texture, finally obtaining a single-layer tunnel 3D model.

[0027] Step S5: Merge the tunnel models For each remaining line layer in step S2, repeat steps S3 to S4 to obtain the single-layer 3D model of the tunnel corresponding to each line layer. Unify the texture display parameters of all single-layer models, including texture resolution and texture mapping ratio, to ensure consistent texture visual effects across different layer models. Based on the spatial coordinates and unique identifier IDs of the boundary line subsets of each line layer, perform spatial stitching on all single-layer models. During the stitching process, automatically correct the boundary coordinate deviations of adjacent models to ensure no cracks or overlaps at the stitching points, ultimately forming a complete 3D model of the tunnel that fully reflects its overall morphology.

[0028] Example 2: Three-dimensional tunnel modeling system based on measured boundary lines and elevation points This system is based on a GIS platform and integrates five functional modules. These modules work together to automate the modeling methods described above. Data import module Core functions include CAD file parsing, layer extraction, and vector data cleaning. CAD file parsing: Supports importing measured CAD drawings of underground tunnels in dwg or dxf format, compatible with AutoCAD 2007 and above, and can automatically identify measured boundary lines, elevation points, and geological attribute-related vector data in the drawings; Layer extraction: Extract the measured boundary line layer, elevation point layer, and geological attribute layer of the tunnel, and save them as a first shapefile, a second shapefile, and a third shapefile respectively. During the extraction process, the boundary line vector is automatically associated with the corresponding geological attributes. Vector data cleanup: Remove redundant auxiliary drawing elements (such as annotation lines, legend blocks, and dimension lines) from CAD drawings, repair broken boundary line vectors (connect breakpoints through node snapping function), and preserve the attribute associations of geological attribute layers during the cleanup process to ensure the integrity of the mapping between boundary line vectors and rock layer hardness, burial depth, and support type information.

[0029] Lane layered module The system receives the first and third shapefiles output by the data import module. Based on the spatial overlap of the measured boundary lines of the tunnels, the tunnel branching logic, and the geological attribute zoning, it performs segmentation processing on the boundary lines in the first shapefile. After segmentation, each subset of boundary lines without spatial overlap is stored in a different line layer, and each line layer is associated with corresponding geological attribute information and a unique identifier ID for subsequent module calls.

[0030] Bottom 3D Surface Building Module It includes a topology checking unit, a region filtering unit, an interpolation unit, an anomaly handling unit, and a 3D surface generation unit, with the following specific functions: Topology check unit: Performs closure, no breakpoints, and no self-intersection checks on any subset of boundary lines output by the roadway layering module; performs line area creation processing on the subset of boundary lines that pass the checks to generate a vector surface of the roadway boundary area; Zone Filtering Unit: Using the vector surface of the roadway boundary zone as a spatial constraint, filter the target elevation points located within the zone in the second shapefile and output them to the interpolation unit. Interpolation Unit: The target elevation points output by the receiving area filtering unit are used to generate contour lines using Kriging interpolation or inverse distance weighted interpolation, and then output to the anomaly processing unit. Anomaly handling unit: Identifies and removes abnormal elevation points using the standard deviation method, triggering the interpolation unit to regenerate contour lines; it also supports the function of moving points on the line, allowing manual adjustment of the spatial position of contour lines, and outputting the adjusted contour lines to the 3D surface generation unit; 3D Surface Generation Unit: Based on the adjusted contour lines and corresponding boundary line subsets, generate the 3D surface at the bottom of the tunnel and output it to the automatic model construction module.

[0031] Automatic model building module It includes a triangular mesh encryption unit, a top surface parameter adjustment unit, a top surface generation unit, a side surface generation unit, and a model stitching unit, with the following specific functions: Triangulation unit: Receives the bottom three-dimensional surface of the tunnel output by the bottom three-dimensional surface construction module, sets the grid accuracy from 0.5m to 2m, and performs triangulation processing using the Delaunay triangulation algorithm to generate the bottom triangulation network; Top surface parameter adjustment unit: calls the geological attribute information of the corresponding line layer in the third shapefile and dynamically adjusts the top surface parameters h0 and g according to preset rules (the adjustment rules are consistent with the top surface parameter adjustment rules in method step S4). Top surface generation unit: Based on the adjusted h0 and g, combined with the shortest horizontal distance w from the bottom triangulation vertex to the boundary line, the vertex movement height is calculated using the formula h=h0+pow(w,g), and the vertex elevation is adjusted to generate the top surface triangulation. Side triangle generation unit: Extract the outer boundary lines of the bottom and top triangular meshes to construct the side triangular mesh; Model stitching unit: The bottom triangular mesh, top triangular mesh and side triangular mesh are stitched together according to the principle of coordinate consistency, and an initial texture matching the support type is assigned to generate a single-layer roadway 3D model, which is then output to the model merging module.

[0032] Model merging module The system receives single-layered 3D tunnel models corresponding to each line layer from the automatic model building module. After unifying the texture display parameters of all models, it performs spatial stitching based on the spatial coordinates and unique identifier ID of each line layer, corrects the boundary deviation of adjacent models, and finally generates the overall 3D tunnel model.

[0033] Example verification Taking the No. 3 underground roadway of a coal mine as an example, the roadway is 800m long, including two turning sections and one intersection section. The support types are bolt support (first 400m) and masonry arch support (last 400m). The burial depth ranges from 420m to 580m, and the rock hardness ranges from 25MPa to 35MPa. The method and system of this invention are used for modeling: Import the measured CAD drawing of the tunnel in dwg format, extract the three types of layers and save it as shp format; The boundary lines are divided according to spatial overlap, branching logic, and geological attributes (rock hardness 30MPa, burial depth 500m, support type) to obtain 4 line layers; A bottom 3D surface is generated for each line layer, with contour lines generated using Kriging interpolation for turning sections and inverse distance weighted interpolation for straight sections; Construct layered models: for the first 400m anchor bolt support section, h0=3m, g=0.3; for the last 400m masonry arch support section, h0=3.15m, g=0.3. The four layered models are merged to obtain the overall three-dimensional model.

[0034] The verification results show that the modeling time is about 40 minutes, which is 80% more efficient than traditional manual modeling; the deviation between the model and the actual measured data is ≤5cm, which meets the accuracy requirements of mining engineering; the model can clearly reflect the differences in roadway morphology under different geological conditions, providing accurate spatial data support for subsequent roadway maintenance and ventilation design.

[0035] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for three-dimensional modeling of tunnels based on measured boundary lines and elevation points, characterized in that, Includes the following steps: S1. Data Preparation: Import the measured CAD drawing of the underground tunnel using the CAD file parsing function, extract the measured boundary line layer and elevation point layer from the measured CAD drawing of the underground tunnel, and simultaneously extract the geological attribute layer associated with the measured CAD drawing of the underground tunnel. The geological attribute layer contains rock layer hardness, burial depth, and support type attribute information; save the measured boundary line layer of the tunnel as a first shapefile, the elevation point layer as a second shapefile, and the geological attribute layer as a third shapefile. S2, Tunnel Layering: Based on the spatial overlap relationship of the measured boundary lines of the tunnels, the tunnel branching logic, and the geological attribute partitioning of the third shapefile, the measured boundary lines of the tunnels in the first shapefile are processed into segmentation lines to obtain at least two non-spatial overlap subsets of boundary lines. Each subset of boundary lines is saved to a different line layer, and each line layer is associated with the corresponding geological attribute information. S3. Determine the three-dimensional surface of the tunnel bottom: Select a subset of boundary lines from any of the line layers mentioned in step S2. After topology checking, line creation area, elevation point filtering, contour line generation and adjustment, generate the corresponding three-dimensional surface of the tunnel bottom based on the adjusted contour lines and the subset of boundary lines. S4. Automatically construct the tunnel model: Triangulate the three-dimensional surface of the tunnel bottom obtained in step S3 to generate a bottom triangular mesh. Dynamically adjust the top surface parameters based on the geological attribute information of the corresponding line layer in the third shapefile. Then, construct a top triangular mesh based on the bottom triangular mesh and the adjusted top surface parameters. Simultaneously, extract the outer boundary lines of the bottom and top triangular meshes to construct a side triangular mesh. Stitch the bottom, top, and side triangular meshes together and apply texture to obtain a single-layered three-dimensional tunnel model. S5. Merge the tunnel models: For each of the remaining line layers in step S2, repeat steps S3 to S4 to obtain the single-layer tunnel 3D model corresponding to each line layer. After unifying the texture display parameters of all the single-layer tunnel 3D models, perform spatial stitching to obtain the overall tunnel 3D model.

2. The method for three-dimensional tunnel modeling based on measured boundary lines and elevation points according to claim 1, characterized in that, In step S1, the measured CAD drawing of the underground tunnel is in dwg or dxf format, and the CAD file parsing function supports file parsing of AutoCAD 2007 and above. Each elevation point in the elevation point layer is associated with an elevation value attribute, and the attribute information of the geological attribute layer comes from the geological annotation layer or attribute block data in the measured CAD drawing of the underground tunnel. During the parsing process, the boundary line vector is automatically associated with the corresponding geological attribute.

3. The method for three-dimensional tunnel modeling based on measured boundary lines and elevation points according to claim 1, characterized in that, In step S2, the geological attribute partitioning is based on the following criteria: hardness partitioning with a rock layer hardness of 30 MPa as the threshold, with rock layer hardness ≥30 MPa forming one partition and rock layer hardness <30 MPa forming another partition; burial depth partitioning with a burial depth of 500 m as the threshold, with burial depth ≥500 m forming one partition and burial depth <500 m forming another partition; branching and support partitioning according to support type, including anchor bolt support, masonry arch support, and anchor spraying support; different line layers include at least a black line layer and a green line layer, each line layer corresponds to an independent tunnel branch or a continuous tunnel segment without spatial overlap, and the boundary line subset of each line layer is associated with a unique identifier ID, which is mapped one-to-one with the geological attribute information in the third shapefile.

4. The method for three-dimensional tunnel modeling based on measured boundary lines and elevation points according to claim 1, characterized in that, In step S4, the rule for dynamically adjusting the top surface parameters based on geological attribute information is as follows: When the rock strata hardness associated with the corresponding line layer is ≥30MPa, the preset tunnel height h0 is adjusted to h. 0base ×1.1, adjust the arching parameter g at the top of the tunnel to g 0base ×0.8, where h 0base The initial preset tunnel height is 3m, g 0base The initial arching parameter is set to 0.3; when the burial depth associated with the corresponding line layer is ≥500m, the preset tunnel height h0 is adjusted to h. 0base ×1.2, adjust the arching parameter g at the top of the tunnel to g 0base ×0.7; When the support type associated with the corresponding line layer is masonry arch support, adjust the preset roadway height h0 to h 0base ×1.05, the arching parameter g remains g 0base constant.

5. The method for three-dimensional tunnel modeling based on measured boundary lines and elevation points according to claim 1, characterized in that, In step S3, the topology check includes checking the closure of the boundary lines, checking the unbroken state of the boundary lines, and checking the non-self-intersection of the boundary lines; the elevation point filtering is based on the roadway boundary area vector surface generated by the line-based area, and filters the target elevation points in the second shapefile file that are located within the roadway boundary area vector surface; the contour line generation adopts the Kriging interpolation method or the inverse distance weighted interpolation method; the contour line adjustment includes regenerating contour lines after identifying and removing abnormal elevation points by the standard deviation method, and adjusting the spatial position of contour lines by moving the point on the line.

6. A three-dimensional modeling system for tunnels based on measured boundary lines and elevation points, characterized in that, This includes a GIS platform, and the following functional modules integrated into the GIS platform: The data import module is used to import measured CAD drawings of underground tunnels through the CAD file parsing function, extract the measured boundary line layer, elevation point layer, and associated geological attribute layer of the tunnel. The geological attribute layer contains rock hardness, burial depth, and support type attribute information. The measured boundary line layer of the tunnel is saved as a first shapefile, the elevation point layer is saved as a second shapefile, and the geological attribute layer is saved as a third shapefile. The tunnel layering module is used to perform segmentation processing on the measured boundary lines of the tunnel in the first shapefile based on the spatial overlap relationship of the measured boundary lines of the tunnel, the tunnel branching logic, and the geological attribute partitioning of the third shapefile. This process yields at least two non-spatial overlap subsets of boundary lines, stores each subset of boundary lines in a different line layer, and associates each line layer with the corresponding geological attribute information. The bottom 3D surface construction module is used to select a subset of boundary lines in any of the line layers, and after topology checking, line creation area, elevation point filtering, contour line generation and adjustment, generate the corresponding bottom 3D surface of the tunnel based on the adjusted contour lines and the subset of boundary lines. The automatic model building module is used to triangulate the three-dimensional surface of the bottom of the tunnel to generate a bottom triangular mesh, dynamically adjust the top surface parameters based on the geological attribute information of the corresponding line layer in the third shapefile, construct a top triangular mesh based on the bottom triangular mesh and the adjusted top surface parameters, extract the outer boundary lines of the bottom and top triangular meshes to construct a side triangular mesh, and stitch the bottom, top, and side triangular meshes together and apply texture to obtain a single-layer tunnel three-dimensional model. The model merging module is used to obtain the corresponding single-layer tunnel 3D model for each of the remaining line layers through the bottom 3D surface construction module and the automatic model construction module. After unifying the texture display parameters of all the single-layer tunnel 3D models, the modules are spatially stitched together to obtain the overall tunnel 3D model.

7. The tunnel three-dimensional modeling system based on measured boundary lines and elevation points according to claim 6, characterized in that, The data import module is also used to perform vector data cleaning on the imported measured CAD drawings of underground tunnels. The vector data cleaning includes deleting redundant auxiliary drawing elements and repairing fractured boundary line vectors. The redundant auxiliary drawing elements include annotation lines and legend blocks. During the cleaning process, the attribute association relationship of the geological attribute layer is preserved to ensure the integrity of the mapping between the boundary line vector and the rock layer hardness, burial depth, and support type information.

8. The tunnel three-dimensional modeling system based on measured boundary lines and elevation points according to claim 6, characterized in that, The automatic model construction module includes a triangulation unit, a top surface parameter adjustment unit, a top surface generation unit, a side surface generation unit, and a model stitching unit. The triangulation unit is used to set the mesh accuracy and perform triangulation processing on the three-dimensional surface of the tunnel bottom. The mesh accuracy is set to 0.5m to 2m, and the triangulation processing adopts the Delaunay triangulation algorithm. The top surface parameter adjustment unit is used to call the geological attribute information of the corresponding line layer in the third shapefile and dynamically adjust the top surface parameters h0 and g according to the preset rules. The preset rules are consistent with the adjustment rules. The top surface generation unit is used to calculate the vertex movement height based on the adjusted h0 and g, combined with the nearest horizontal distance w from the vertex of the bottom triangular mesh to the boundary line, using the formula h=h0+pow(w,g), and adjust the vertex elevation to generate the roadway top surface triangular mesh; the side surface generation unit is used to extract the outer boundary lines of the bottom and top triangular meshes and construct the side triangular meshes; the model stitching unit is used to stitch the bottom, top, and side triangular meshes according to the principle of coordinate consistency and assign an initial texture matching the support type.

9. The tunnel three-dimensional modeling system based on measured boundary lines and elevation points according to claim 6, characterized in that, The bottom 3D surface construction module includes a topology checking unit, a region filtering unit, an interpolation unit, an anomaly handling unit, and a 3D surface generation unit; The topology checking unit is used to perform closure checks, no-breakpoint checks, and no-self-intersection checks on the boundary line subsets, and to perform line area creation processing on the boundary line subsets that pass the checks to generate the roadway boundary area vector surface. The zone filtering unit is used to filter target elevation points located within the zone in the second shapefile based on the vector surface of the lane boundary zone. The interpolation unit is used to interpolate the target elevation points using Kriging interpolation or inverse distance weighted interpolation to generate contour lines; The three-dimensional surface generation unit is used to generate a three-dimensional surface at the bottom of the tunnel based on the adjusted contour lines and corresponding boundary line subsets.

10. The tunnel three-dimensional modeling system based on measured boundary lines and elevation points according to claim 9, characterized in that, The anomaly handling unit is used to identify and remove abnormal elevation points using the standard deviation method, and trigger the interpolation unit to regenerate contour lines; and / or, the anomaly handling unit supports adjusting the spatial position of contour lines by moving points on the line.

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