Method and system for automatically identifying contour features of blasting area of bench blasting

Abstract

The invention provides an automatic identification method and system for contour features of a blasting area of bench blasting, and the method comprises the following steps: defining a contour surface type of blasting design based on blasting design requirements; intercepting a target three-dimensional surface patch excavation body from the three-dimensional terrain or the design model, and determining the construction sequence of the target three-dimensional surface patch excavation body relative to other excavation bodies; obtaining normal vectors and geometric features of each patch of the target three-dimensional patch excavation body, and identifying the contour surface type to which each patch belongs according to the defined contour surface type; and extracting and fitting to generate contour lines and contour points based on the identified various contour surfaces. According to the method, the time for manual identification in the blasting area is effectively shortened, the data processing efficiency is improved, and application and development of automation and intelligence of intelligent blasting design in surface mines, large capital construction projects and the like are promoted.

Description

Technical Field

[0001] This invention belongs to the field of bench blasting technology, and particularly relates to an automatic identification method and system for the contour features of bench blasting zones. Background Technology

[0002] With the continuous development of intelligent construction, intelligent blasting has been widely used in large-scale infrastructure projects and open-pit mines. The ultimate goal of intelligent blasting design is to use computers to automate, intelligently, and efficiently design blasting parameters and borehole layout. In three-dimensional bench blasting design, the layout of blasting holes first requires accurate identification of the spatial structural characteristics of the excavation body, i.e., the types of points, lines, and surfaces, before further arranging the blasting holes. The surfaces of the excavation body include permanent contour surfaces, upper and lower bottom surfaces, true free surfaces, pre-splitting surfaces, and temporary surfaces. While manual methods can mark the positions of points, lines, and surfaces in an intelligent blasting design system, this process is time-consuming, increasing time costs and making it difficult to meet the needs of rapid and automated design. Summary of the Invention

[0003] This invention proposes a computer-based automatic identification method for the contour features of blasting zones in bench blasting, which is used in intelligent blasting design systems for the automatic identification and marking of the selected blasting excavation contour surfaces.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: An automatic identification method for the contour features of a bench blasting zone includes the following steps: Based on the requirements of blasting design, the contour surface type of blasting design is defined; Extract the target 3D excavation area from the 3D terrain or design model and determine its construction sequence relative to other excavation areas; Obtain the normal vectors and geometric features of each facet of the target three-dimensional excavated body, and identify the contour surface type to which each facet belongs based on the defined contour surface type; Based on the identified contour surfaces, contour lines and contour points are extracted and fitted to generate contours.

[0005] Furthermore, the types of the profile surfaces include: true free surfaces, pre-cracked surfaces, permanent profile surfaces, and temporary surfaces.

[0006] Furthermore, by comparing the spatial location and construction sequence of different excavation bodies, the order of the current excavation body with other excavation bodies can be determined.

[0007] Furthermore, identifying the contour surface type to which each patch belongs includes: Top and bottom surface identification sub-steps: Based on multiple indicators of the normal vector of each facet, the multiple identification indicators are weighted and scored, and the top surface subset is identified from the three-dimensional facet set according to a preset total score threshold; based on the height position of the facet, the bottom surface subset is identified from the remaining facets; the remaining facets constitute the side surface subset; Free face identification sub-step: Identify the face pieces in the side face piece set that do not belong to any planar area as free faces; if it is a pre-splitting face of the previous blasting zone, it will be automatically identified as the current free face when dividing the blasting zone in the next stage; Pre-cracked surface or permanent contour surface identification sub-step: Cluster the face patches in the side panel subset according to their normal vector direction, find large-area flat areas with spatial connectivity within each group, and identify them as pre-cracked surfaces or permanent contour surfaces.

[0008] Furthermore, in the top and bottom surface identification sub-step, the normal vector of each surface has multiple indices including at least upward orientation, slope, roundness, and levelness.

[0009] Furthermore, in the free surface identification sub-step, for free surfaces that are natural slopes, they are identified by determining whether their surface normal vectors deviate from any clustering plane region; for free surfaces that are pre-splitting surfaces in the previous blasting zone, their identification information is directly inherited from the blasting stage data.

[0010] Furthermore, in the sub-step of identifying pre-cracked surfaces or permanent contour surfaces, surface patches are clustered and grouped using a normal vector angle threshold, and spatially connected regions are extracted using a breadth-first search algorithm. When the area of ​​a certain connected region exceeds a specified proportion of the total surface area of ​​the excavation body, the region is identified as a pre-cracked surface or a permanent contour surface.

[0011] Furthermore, the identified contour surfaces are extracted and fitted to generate contour lines and contour points, including: Slope crest line generation sub-step: Extract the identified boundary point set of the top surface, project it onto the fitting plane, calculate the two-dimensional convex hull, and then generate a smooth slope crest line through arc length parameterized interpolation; Slope bottom line generation sub-step: Extract the identified boundary point set of the bottom surface, project it onto the fitting plane, calculate the two-dimensional convex hull, and then generate a smooth slope bottom line through arc length parameterized interpolation; Endpoint generation sub-step: On the slope crest line and slope bottom line, perform uniform parameterized interpolation based on the arc length to generate a series of slope top points and slope bottom endpoints.

[0012] Furthermore, the least squares method is used to project the three-dimensional boundary point set onto the best-fit plane for two-dimensional convex hull calculation.

[0013] On the other hand, the present invention provides an automatic marking system for the contour features of a stepped blasting zone, comprising: Type definition module: It is used to define the contour surface type of the blasting design based on the blasting design requirements; Excavation processing module: It is used to extract the target 3D surface excavation body from the 3D terrain or design model and determine its construction sequence relative to other excavation bodies; Contour surface recognition module: It is used to obtain the normal vector and geometric features of each facet of the target three-dimensional facet excavation body, and to identify the contour surface type to which each facet belongs based on the defined contour surface type; Contour line and point generation module: It is used to extract and fit contour lines and contour points based on the identified contour surfaces.

[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention proposes an automatic identification method for the contour features of bench blasting zones when using computers for blasting design. This method can automatically determine the types of surfaces, lines, and points within the selected bench blasting zone, providing reliable support for the subsequent automatic layout of blasting holes. This method effectively reduces the time spent on manual identification within the blasting zone, improves data processing efficiency, and promotes the application and development of automation and intelligence in intelligent blasting design in open-pit mines, large-scale infrastructure projects, and other fields. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a flowchart of an embodiment of the present invention; Figure 2 This is a schematic diagram of the normal vector of the free surface portion of the explosive body according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the permanent contour surface in an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the calculation of the included angle of the spatial normal vectors in an embodiment of the present invention; Figure 5 This is a schematic diagram of the top surface point set according to an embodiment of the present invention; Figure 6 This is a schematic diagram of convex hull boundary extraction according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the interpolation optimization algorithm in an embodiment of the present invention, where (a) is the original boundary line and (b) is the optimized boundary line. Detailed Implementation

[0017] The technical solutions of 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.

[0018] In specific implementation, the method proposed in the technical solution of this invention can be automatically executed by those skilled in the art using computer software technology. System devices for implementing the method, such as computer-readable storage media storing the corresponding computer program of the technical solution of this invention and computer equipment including the computer program running the corresponding computer program, should also be within the protection scope of this invention.

[0019] Example 1 Figure 1 An automatic identification method for the contour features of a stepped blasting zone provided in this disclosure includes the following steps: Step A: Based on the blasting design requirements, define the contour surface type of the blasting design; Step B: Extract the target 3D excavation area from the 3D terrain or design model, and determine its construction sequence relative to other excavation areas; Step C: Obtain the normal vectors and geometric features of each facet of the target three-dimensional excavated body, and identify the contour surface type to which each facet belongs based on the defined contour surface type; Step D: Extract and fit contour lines and contour points based on the identified contour surfaces.

[0020] In step A of this embodiment, the outline of the blasting zone includes: (1) True free surface: The surface is exposed to the air without being constrained by rock mass; (2) Pre-splitting surface: The surface controlled or formed by pre-splitting blasting to ensure that the structure has good integrity after blasting; (3) Permanent outline surface: The final excavation boundary surface, consistent with the construction design; (4) Temporary face: When the blasting zone is large, the construction needs to be carried out in stages. Some faces only exist in the current excavation face and are removed or changed as faces of the subsequent blasting zone, including the construction pre-splitting face and the new surrounding face.

[0021] In step C of this embodiment, the identification of the contour surface is mainly based on a comprehensive judgment of normal vectors, geometric features, and spatial relationships. Specifically, it includes: Step C1: Top and bottom face recognition sub-step: Based on the normal vector direction, curvature, height and spatial position relationship, set indicators such as upward orientation, slope score, roundness and levelness. After height filtering, this embodiment sets the weight of upward orientation to 0.4, the weight of slope score to 0.1, the weight of roundness to 0.3, the weight of levelness to 0.2, and the total score threshold to 0.6. The top face is automatically identified by a weighted scoring algorithm, and the bottom face is identified by height position. The side face is obtained by set calculation. Upward orientation is defined as the projection component of the normal vector of a surface onto the vertical direction (Z-axis), with the symbol denoted as . The formula is: (1) in, For the normal vector of the surface Z Axial components.

[0022] The slope score requires first calculating the angle between the normal vector of the surface and the vertical direction using equation (2). Then, use equation (3) to convert it into a slope score. : (2) (3) in, For the normal vector of the surface Z Axial components.

[0023] Circularity is an indicator used to measure how closely a surface resembles a circle, and is defined by the symbol . The formula is: (4) in, It is the area of ​​the triangular facet. It is the perimeter of the surface.

[0024] Horizontality is used to quantify the alignment between the normal vector of a surface and the horizontal direction, and is defined by the symbol . The formula is: (5) in, For the normal vector of the surface Z Axial components.

[0025] The height characteristic of a triangular facet is determined by the average height of its vertices. As shown in equation (6), the bottom surface, i.e., the combination of facets with the lowest height, can be directly identified based on its height characteristics. Furthermore, a height filter can be set to assist in top surface identification, as shown in equation (7), which sets the facet height... Normalization As shown in Equation (8), when identifying the top surface, the face with the lower normalized height is filtered out.

[0026] (6) (7) in For the triangular facet vertices Z Coordinate values The highest point of the model Z coordinate, The lowest point of the model Z coordinate.

[0027] After identifying the top and bottom surfaces, the set of side surfaces can be obtained through set calculation, as shown in equation (8): (8) in For the side set, For the set of all facets of the model, For the top face set, It is the base set.

[0028] Step C2: Identification of Free Surfaces: A free surface is either a natural slope surface or a pre-splitting surface from a previous blasting zone. Natural slope surfaces are uneven with significant curvature variations; while pre-splitting surfaces from previous blasting stages, serving as free surfaces for subsequent blasting zones, are cut and have smooth surfaces. If the free surface is a natural slope, it is determined based on the constantly changing normal vector. Figure 2 As shown, all surfaces that do not belong to any planar area are marked as free surfaces; if it is a pre-splitting surface of the previous blasting zone, it will be automatically marked as the current free surface when dividing the blasting zone in the next stage.

[0029] Step C3: Sub-step for identifying pre-cracked surfaces (permanent contour surfaces): Group all surfaces according to their normal vector directions. The default threshold for the included angle within a group is 1.0 degree; angles less than 1° are clustered into the same group. Within each normal vector group, find the set of spatially connected surfaces and calculate their total area. If the area of ​​a connected region exceeds a set proportion (e.g., 5%) of the total model area, it is identified as a planar region. From all planar regions, exclude the already identified bottom surfaces; the remaining parts are the pre-cracked surfaces (permanent contour surfaces), such as... Figure 3 As shown.

[0030] like Figure 4 As shown, the angle between spatial normal vectors is calculated using the following formula: (9) in, and They are dough pieces and dough sheets unit normal vector ， The angle between the two normal vectors is expressed in degrees.

[0031] Step D: Automatic identification of contour lines and contour points. This includes the slope crest line, slope base line, and the top and bottom points of the slope. Specifically, it includes: Step D1: Automatic identification and fitting of the slope crest line. Extract the boundary point set of the top surface, such as... Figure 5 As shown; the point set is projected onto the least squares fitting plane, and the slope crest line is extracted using the convex hull algorithm, as follows. Figure 6 As shown. Then, the boundary points are uniformly interpolated using an arc-length parameterization method and connected to form a smooth boundary line, as shown. Figure 7 As shown.

[0032] Step D2: Automatic identification and fitting of the slope baseline. Extract the boundary point set of the bottom surface, project the point set onto the least squares fitting plane, extract the slope baseline using the convex hull algorithm, then uniformly interpolate the boundary points using the arc length parameterization method, and connect them to form a smooth boundary line; Step D3: Slope crest point: Uniform interpolation is performed on the boundary points of the candidate slope crest line using the arc length parameterization method to obtain uniform endpoints on the slope crest line; Step D4: Slope bottom endpoints: Uniform interpolation is performed on the boundary points of the candidate slope bottom line using the arc length parameterization method to obtain uniform endpoints on the slope bottom line; Example 2 This embodiment provides an automatic marking system for the contour features of a stepped blasting zone, including: Type definition module: It is used to define the contour surface type of the blasting design based on the blasting design requirements; Excavation processing module: It is used to extract the target 3D surface excavation body from the 3D terrain or design model and determine its construction sequence relative to other excavation bodies; Contour surface recognition module: It is used to obtain the normal vector and geometric features of each facet of the target three-dimensional facet excavation body, and to identify the contour surface type to which each facet belongs based on the defined contour surface type; Contour line and point generation module: It is used to extract and fit contour lines and contour points based on the identified contour surfaces.

[0033] It should be understood that any parts not described in detail in this specification belong to the prior art.

[0034] It should be understood that the above description of the preferred embodiments is quite detailed, but this should not be construed as limiting the scope of protection of this invention. It is neither necessary nor possible to exhaustively describe all possible implementations. Those skilled in the art, guided by this invention, can make substitutions or modifications without departing from the scope of the claims, all of which fall within the scope of protection of this invention. The scope of protection of this invention should be determined by the appended claims.

Claims

1. A method for automatic identification of a blast area profile feature of a bench blast, characterized in that, The method comprises the following steps: Defining the profile surface type of the blasting design based on the blasting design requirements; Cutting the target three-dimensional surface patch excavation body from the three-dimensional terrain or design model, and clearly defining the construction sequence thereof relative to other excavation bodies; Obtaining the normal vector and geometric characteristics of each surface patch of the target three-dimensional surface patch excavation body, and identifying the profile surface type to which each surface patch belongs according to the defined profile surface type; Extracting and fitting the profile line and profile point based on the identified profile surface types.

2. The method according to claim 1, wherein, The profile surface types include a true free surface, a pre-splitting surface, a permanent profile surface and a temporary surface.

3. The method according to claim 1, wherein, The construction sequence of the current excavation body relative to other excavation bodies is determined by comparing the spatial positions and construction sequences of different excavation bodies.

4. The method according to claim 1, wherein, The identification of the profile surface type to which each surface patch belongs comprises: A top surface and bottom surface identification sub-step: based on multiple indexes of the normal vector of each surface patch, the multiple identification indexes are weighted and scored, and a top surface subset is identified from the three-dimensional surface patch set according to a preset total score threshold; based on the height position of the surface patch, a bottom surface subset is identified from the remaining surface patches; the remaining surface patches constitute a side surface subset; A free surface identification sub-step: the surface patches in the side surface patch set that do not belong to any planar region are identified as free surfaces; if the surface is a construction pre-splitting surface of a previous blasting blast area, it is directly identified as the current free surface in the next stage of blasting blast area division; A pre-splitting surface or permanent profile surface identification sub-step: the surface patches in the side surface subset are clustered and grouped according to their normal vector directions, spatially connected large-area flat regions in each group are found, and the regions are identified as pre-splitting surfaces or permanent profile surfaces.

5. The method according to claim 4, wherein, In the top surface and bottom surface identification sub-step, the multiple indexes of the normal vector of each surface patch at least include upwardness, slope, circularity and levelness.

6. The method according to claim 4, wherein, In the free surface identification sub-step, for a free surface that is a natural slope, whether the surface patch normal vector deviates from any clustered planar region is judged to identify the free surface; for a free surface that is a pre-splitting surface of a previous blast area, the identification information is directly inherited in the blasting staging data.

7. The method according to claim 4, wherein, In the pre-splitting surface or permanent profile surface identification sub-step, a normal vector angle threshold is used for surface patch clustering and grouping, and a breadth-first search algorithm is used to extract spatially connected regions; when the area of a connected region exceeds a specified proportion of the total surface area of the excavation body, the region is identified as a pre-splitting surface or a permanent profile surface.

8. The method of claim 1, wherein, The extraction and fitting of the profile line and profile point based on the identified profile surface types comprise: A slope top line generation sub-step: the boundary point set of the identified top surface is extracted, the point set is projected onto a fitting plane, a two-dimensional convex hull is calculated, and a smooth slope top line is generated through arc length parameterization interpolation; a slope bottom line generation sub-step: the boundary point set of the identified bottom surface is extracted, the point set is projected onto a fitting plane, a two-dimensional convex hull is calculated, and a smooth slope bottom line is generated through arc length parameterization interpolation; an end point generation sub-step: a series of slope top end points and slope bottom end points are generated on the slope top line and the slope bottom line through uniform parameterization interpolation according to the arc length.

9. The method for automatically identifying the characteristics of a blast area profile in a bench blasting according to claim 8, characterized in that, A least squares method is used to project the three-dimensional boundary point set onto the best fitting plane for two-dimensional convex hull calculation.

10. A system for automatic identification of blast area profile features in a bench blasting, characterized by The method comprises: A type definition module: used for defining the profile surface type of the blasting design based on the blasting design requirements; The excavation body processing module is used to intercept a target three-dimensional facet excavation body from a three-dimensional terrain or design model and to determine the construction sequence of the target three-dimensional facet excavation body relative to other excavation bodies. The contour surface identification module is used to obtain normal vectors and geometric features of each facet of the target three-dimensional facet excavation body and to identify the contour surface type to which each facet belongs according to a defined contour surface type. The contour line and point generation module is used to extract and fit contour lines and contour points based on the identified contour surface types. The automatic identification system of the bench blasting blast area contour feature is used to perform the steps in the automatic identification method of the bench blasting blast area contour feature according to any one of claims 1-9.

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