Rock mass structural surface characteristic parameter calculation and matching surface generation method and system based on three-dimensional point cloud
By processing 3D point cloud data using MatlabAPP, generating coordinate files that match the original structural surfaces, and calculating feature parameters, the shortcomings of existing technologies in calculating 3D features of rock mass structural surfaces are solved, and accurate data support for rock mass engineering is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-04-10
AI Technical Summary
Existing technologies cannot effectively utilize three-dimensional laser scanning technology to calculate the three-dimensional characteristic parameters of rock mass structural surfaces, resulting in a lack of accurate data support for rock mass engineering reinforcement and design.
MatlabAPP is used to perform coordinate transformation and processing of 3D point cloud data, generating another structural surface coordinate file that matches the original structural surface. Combined with the calculation formulas for tortuosity, undulation angle, roughness coefficient, relative undulation and maximum height difference, the structural surface characteristic parameters are accurately calculated and the schematic diagram is displayed.
It provides accurate calculation results of rock mass structural surface characteristic parameters, supports structural surface contact characteristics and mechanical calculations, and provides an efficient data foundation for the reinforcement and design of rock mass engineering.
Smart Images
Figure CN121837542A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of rock mass structure surface feature identification, and particularly relates to a rock mass structure surface feature parameter calculation and mating surface generation method based on three-dimensional point clouds. BACKGROUND
[0002] The discontinuous surface widely existing in the rock mass plays a control role in the deformation and failure of the rock mass. The joint is an important form of the discontinuous surface of the rock mass, which refers to the fracture of the rock on both sides without displacement or only a small amount of displacement along the fracture surface. The mechanical properties of the joint surface are important factors for evaluating the stability of the rock mass. The existence of the joint has an important influence on the mechanical properties of the rock, and the research on the strength of the jointed rock mass not only has theoretical significance, but also can directly guide the reinforcement and design of the related rock mass engineering. The mechanical properties of the joint depend largely on the geometric features of the joint surface, and how to measure the surface morphology of the rock mass structure surface and express the measurement results by a specific parameter index has always been a hot issue in the field of geotechnical engineering.
[0003] The commonly used geometric shape characterization parameters of the structure surface are only used to describe the structure features of the two-dimensional section line. With the development of three-dimensional scanning technology, the method of collecting structure surface data based on three-dimensional laser scanning technology to calculate and research the structure surface features has gradually become a trend. The calculation results of the three-dimensional structure surface feature parameters can be used for researches in many aspects such as the seepage and mechanical properties of the structure surface, and therefore it is an urgent need to provide a rock structure surface feature parameter calculation method based on a three-dimensional laser scanning model. SUMMARY
[0004] The application aims to overcome the defects of the prior art and provide a rock mass structure surface feature parameter calculation and mating surface generation method and system based on three-dimensional point clouds.
[0005] A rock mass structure surface feature parameter calculation and mating surface generation method based on three-dimensional point clouds comprises the following steps: Step S1, coordinate conversion: The Matlab APP is opened, the sample size of the rock structure surface sample and the number of pixel points on each side are filled in the window interface of the preset coordinate conversion system according to the actual situation, then the three-dimensional structure surface point cloud file to be converted is selected, the structure surface point cloud coordinate data obtained by the three-dimensional laser scanning is converted into real coordinate data, a real coordinate data file is obtained, and the converted real coordinate data file is saved in the Matlab path folder; Step S2, single structure surface generation mating structure surface: Open the MatlabAPP, in the window interface of the preset coordinate transformation system, select the transformed real coordinate data file, generate another structural plane coordinate file that matches the original structural plane based on the real coordinate data file, forming a pair of matching structural plane data files with spatial geometric complementary relationship, and save them in the Matlab path folder; Step S3, file reading: Open the Matlab app, select the 3D structural surface point cloud file that you want to read. After selecting the file, Matlab will display the file name in the software interface and add the file to the Matlab path folder. At the same time, the coordinate data in the file will be imported into Matlab. Step S4, parameter calculation: Matlab uses imported coordinate data to calculate the tortuosity, undulation angle, roughness coefficient, relative undulation, and maximum height difference of the structural surface based on the set tortuosity calculation formula, undulation angle calculation formula, roughness coefficient calculation formula, relative undulation, and maximum height difference calculation formula, and displays the calculation results. Step S5, structural plane diagram shown: Matlab uses the imported coordinate data to draw a schematic diagram of the structural surface and displays it on the software interface. The generated schematic diagram includes coordinate axes and color gradients divided by height.
[0006] Furthermore, in step S1, the process of constructing the three-dimensional structural surface point cloud file is as follows: Step S1.1, Preparation of rock structural surface samples: Rock structural surface samples are prepared by using natural structural surfaces present in the rock or by artificial splitting or direct shearing experiments, and the rock blocks are processed into the predetermined size; Step S1.2, Acquisition of structural surface point cloud data: A non-contact, high-precision laser scanner is used to measure the surface morphology of rock structures. Based on the principle of pulsed laser ranging, the horizontal azimuth angle between the laser beam and the scanned target is collected. ), vertical pitch angle ( ) and ranging ( Based on the coordinate formula, the three-dimensional coordinates of the target object in the coordinate system can be obtained, and finally a set of spatial points with three-dimensional coordinate (X, Y, Z) information is obtained. The set of spatial points is the point cloud data, which is stored as the three-dimensional structural surface point cloud file of the rock structural surface sample.
[0007] Further, in step S1.2, the coordinate formula is: .
[0008] Further, in the step S1.2, when the point cloud data obtained by scanning is processed, in order to eliminate the influence of the distortion at the scanning boundary or in the case of only selecting the local point cloud data of the scanned structural surface, the Geomagic Wrap software is used for data cutting and coordinate correction operation, and the specific process is as follows: The required area is determined by directly drawing a selection area in the model view through the left mouse button, or the target area is selected by using a rectangular selection tool; After the selection area is determined, the reverse selection area command is executed by clicking the right mouse button, and the reverse selected area is reversed; then the redundant point cloud data in the reverse selected area is deleted, so as to retain the target structural surface area and remove the redundant data at the scanning boundary; The joint surface after cutting is in an inclined state in the scanning coordinate system, and the coordinate correction is performed to make the joint surface reference plane coincide with the XY plane, and the specific operation is as follows: The joint surface is selected by the left mouse button; if there is a reference plane, the reference plane is also selected; In the menu bar, select Feature-Plane-Best Fit in sequence, generate a fitting plane based on the selected point cloud or reference plane, and take the plane as a new XY plane; The command of Align-Align to Global-Create is executed to align the fitting plane with the global XY plane, so as to realize the coordinate alignment of the joint surface.
[0009] Further, in the step S3, the three-dimensional structural surface point cloud file includes a real coordinate data file and a matching structural surface data file.
[0010] Further, in the step S4, The tortuosity calculation formula is: ; The relief angle calculation formula is: ; Wherein, is the X-direction tortuosity; is the number of profile lines; is the number of points on the profile line; is the profile line visual length; is the height of point (i, j); is the number of sample points along the X direction of the jth profile line; is the number of X-direction profile lines; is the height value of the ith sample point; is the scanning interval; The roughness coefficient calculation formula is: ; ; ; wherein, is the first derivative root mean square of the profile line; L is to obtain the length of the profile line; and is the point cloud coordinate on the profile line; N is the total number of samples; is the three-dimensional structure surface roughness; is the roughness of each profile line; m is the number of profile lines; The relative relief degree calculation formula is: ; ; The maximum height difference calculation formula is: ; wherein, is the maximum height value of the profile line; is the minimum value; is the straight line length of the profile line; is the number of profile lines in the X direction.
[0011] A rock mass structure surface feature parameter calculation and matching surface generation system based on three-dimensional point cloud, comprising: a Matlab APP module for reading a three-dimensional structure surface point cloud file, generating a real coordinate data file, generating a matching structure surface data file, generating a structure surface tortuosity parameter, generating a structure surface relief angle parameter, generating a structure surface roughness coefficient parameter, generating a structure surface relative relief degree parameter, generating a structure surface maximum height difference parameter, and generating a structure surface schematic diagram; a storage module for storing a three-dimensional structure surface point cloud file, a real coordinate data file, and a matching structure surface data file.
[0012] As described above, due to the adoption of the above technical solutions, the beneficial effects of the present application are: 1. In the present application, the structure surface point cloud coordinate data of the rock structure surface sample is obtained based on three-dimensional laser scanning, real coordinate conversion is performed through Matlab APP, and the spatial position and geometric shape of the corresponding surface are calculated according to the point cloud data of the original scanning surface, so as to generate another structure surface coordinate file matched with the original structure surface, form a pair of matching structure surface data with spatial geometric complementary relationship, and provide accurate data basis for contact feature calculation and mechanical calculation.
[0013] 2. In this invention, Matlab uses imported coordinate data to calculate the tortuosity, undulation angle, roughness coefficient, relative undulation, and maximum height difference of the structural surface based on the set tortuosity calculation formula, undulation angle calculation formula, roughness coefficient calculation formula, relative undulation, and maximum height difference calculation formula, and displays the calculation results and a schematic diagram of the structural surface, which facilitates researchers to efficiently obtain parameters and data. Attached Figure Description
[0014] Figure 1 This is a window interface diagram showing the parameter calculation and structural surface schematic diagram of the present invention.
[0015] Figure 2 This is a window interface diagram for coordinate transformation and the generation of mating structural surfaces from a single structural surface in this invention.
[0016] Figure 3 This is a surface morphology diagram of the three-dimensional structure of the present invention.
[0017] Figure 4 This is a schematic diagram of the three-dimensional laser scanning coordinate system of the present invention. Detailed Implementation
[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention are described clearly and completely below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Furthermore, the specific embodiments described herein are only used to explain this invention and are not intended to limit this invention.
[0019] A method for calculating characteristic parameters of rock mass structural surfaces and generating mating surfaces based on three-dimensional point clouds includes the following steps: Step S1, coordinate transformation: Open the MatlabAPP. In the window interface of the preset coordinate transformation system, fill in the sample size of the rock structure surface and the number of pixels on each side according to the actual situation. Then select the three-dimensional structure surface point cloud file to be transformed. Convert the coordinate data of the structure surface point cloud obtained by three-dimensional laser scanning into real coordinate data to obtain the real coordinate data file. The converted real coordinate data file is saved in the Matlab path folder. Step S2, generating mating structural surfaces from a single structural surface: Open the MatlabAPP, in the window interface of the preset coordinate transformation system, select the transformed real coordinate data file, generate another structural plane coordinate file that matches the original structural plane based on the real coordinate data file, forming a pair of matching structural plane data files with spatial geometric complementary relationship, and save them in the Matlab path folder; Step S3, file reading: Open the Matlab APP, select the three-dimensional structural plane point cloud file that needs to be read, select the file, and the Matlab displays the file name on the software interface and adds the file to the Matlab path folder. At the same time, the coordinate data in the file is imported into Matlab; Step S4, parameter calculation: Matlab calculates the tortuosity, relief angle, roughness coefficient, relative relief degree and maximum height difference of the structural plane based on the set tortuosity calculation formula, relief angle calculation formula, roughness coefficient calculation formula, relative relief degree calculation formula and maximum height difference calculation formula, and displays the calculation results using the imported coordinate data. Step S5, structural plane schematic diagram display: Matlab uses the imported coordinate data to draw a structural plane schematic diagram and displays it on the software interface. The generated schematic diagram contains coordinate axes and a color gradient divided by height.
[0020] Further, in step S1, the construction process of the three-dimensional structural plane point cloud file is as follows: Step S1.1, rock structural plane sample preparation: Natural structural planes in rocks or artificial splitting or straight shear tests are used to prepare rock structural plane samples. The rock mass is processed into a predetermined size. Step S1.2, structural plane point cloud data acquisition: A non-contact high-precision laser scanner is used to measure the rock structural plane topography. Based on the principle of pulsed laser ranging, the horizontal azimuth angle (θ), the vertical pitch angle (φ) and the range (r) between the laser beam and the scanning target are collected. Based on the coordinate formula, the three-dimensional coordinates of the target object in the coordinate system can be obtained. Finally, the spatial point set with three-dimensional coordinate (X, Y, Z) information is obtained, which is the point cloud data, and is stored as the three-dimensional structural plane point cloud file of the rock structural plane sample.
[0021] Further, in step S1.2, the coordinate formula is as follows: .
[0022] Further, in step S1.2, when processing the scanned point cloud data, in order to eliminate the distortion influence at the scanning boundary or in the case of only selecting local point cloud data of the scanned structural plane, Geomagic Wrap software is used for data cutting and coordinate correction operation. The specific process is as follows: Draw the selected area directly in the model view by left mouse button, or use the rectangular selection tool to select the target area; After the completion of the selection, click the right mouse button, execute the reverse selection command, reverse the selected area; then delete the redundant point cloud data in the reverse selected area, thereby retaining the target structural surface area and removing the redundant data at the scanning boundary; The coordinate system is adjusted to the cutting joint surface in the scanning coordinate system, and the reference surface of the joint surface is coincided with the XY plane through coordinate correction. The specific operation is as follows: The joint surface is selected by the left mouse button; if there is a reference plane, the reference plane is also selected; The menu bar is selected in sequence, feature-plane-best fitting, a fitting plane is generated based on the selected point cloud or reference plane, and the plane is taken as a new XY plane; The command of align-align to global-create is executed to align the fitting plane with the global XY plane, so as to realize the coordinate adjustment of the joint surface.
[0023] Further, in the step S3, the three-dimensional structural surface point cloud file includes a real coordinate data file and a matching structural surface data file.
[0024] Further, in the step S4, The tortuosity calculation formula is: ; The relief angle calculation formula is: ; Wherein, X direction tortuosity; The number of profile lines; The number of points on the profile line; The profile line visual length; The height of point (i, j); The number of X direction sample points of the jth profile line; The number of X direction profile lines; The height value of the ith sample point; The scanning interval; The roughness coefficient calculation formula is: ; ; ; Wherein, The first derivative root mean square of the profile line; L The length of the profile line is obtained; And The point cloud coordinates on the profile line; N The total number of sample points; The roughness of the three-dimensional structural surface; is the roughness of each profile line; m is the number of profile lines; The relative relief degree calculation formula is: ; ; The maximum height difference calculation formula is: ; wherein, is the maximum height value of the profile line; is the minimum value; is the straight line length of the profile line; is the number of profile lines in the X direction.
[0025] A rock mass structure surface feature parameter calculation and matching surface generation system based on three-dimensional point cloud, comprising: a Matlab APP module for reading a three-dimensional structure surface point cloud file, generating a real coordinate data file, generating a matching structure surface data file, generating a structure surface tortuosity parameter, generating a structure surface relief angle parameter, generating a structure surface roughness coefficient parameter, generating a structure surface relative relief degree parameter, generating a structure surface maximum height difference parameter, and generating a structure surface schematic diagram; a storage module for storing a three-dimensional structure surface point cloud file, a real coordinate data file, and a matching structure surface data file.
[0026] Embodiment (1) A three-dimensional laser scanner is used to obtain structure surface point cloud parameters of a rock sample, named 100X100.top.xyz. The obtained point cloud file, a three-dimensional structure surface topography diagram is shown in Figure 3 .
[0027] (2) Point cloud data is converted into actual size Since the upper and lower joint surfaces have a very high matching degree, only the top surface is processed, and after processing, its matching joint surface is generated as the bottom surface.
[0028] Open the Matlab APP, enter the corresponding window, click "coordinate conversion", and in the first function, input the sample size: 100, the number of pixel points on each side: 512, select the file 100X100.top.xyz, and the window interface diagram of coordinate conversion and single structure surface generating matching structure surface is shown in Figure 2 . The obtained file is transform.txt.
[0029] (3) 1mm interval sampling, open transform.txt with wrap, create a curve and select the curve, then create points, select the generated points, right-click to save as top.asc, which is used to generate the matching joint surface; select the next point generated in the previous step, encapsulate, and save the generated surface domain file as an STL (binary) file named top.stl, which is the top surface of the structural surface file.
[0030] (4) Open top.stl with wrap, repeat step (3), but set the section interval and point interval to 0.5mm, save the generated points as topcount.asc, which is used for parameter calculation.
[0031] (5) Generating a matching joint surface from a single joint surface Find top.asc and topcount.asc, open them with Notepad and delete the table header, Open Matlab APP and click "Coordinate Transformation", select file top.asc, generate matching joint surface point cloud data otherside.txt with an interval of 1mm, open otherside.txt with wrap, encapsulate it into a surface domain, and save the generated surface domain file as bottom.stl, which is the bottom surface of the structural surface file.
[0032] After completing the above steps, open Matlab APP and click "Coordinate Transformation", in the second function, select file topcount.asc, generate matching joint surface point cloud data otherside.txt with an interval of 0.5mm, and rename the file as bottomcount.txt.
[0033] (6) Parameter calculation Open Matlab APP, in the window interface of parameter calculation and structural surface diagram, as shown in Figure 1 , click "Select File" to open topcount.asc and bottomcount.txt respectively, and get the corresponding parameter calculation results and obtain the structural surface diagram.
[0034] As described above is an embodiment of the present application. The foregoing is each preferred embodiment of the present application, and each preferred embodiment can be arbitrarily combined and used if not obviously contradictory or with a certain preferred embodiment as a prerequisite. The embodiments and specific parameters in the embodiments are only for clearly describing the verification process of the application and are not intended to limit the patent protection scope of the application, which is still subject to the claims, and any equivalent structural changes made by using the content of the specification and drawings should also be included in the protection scope of the application.
Claims
1. A method for calculating characteristic parameters of rock mass structural surfaces and generating mating surfaces based on three-dimensional point clouds, characterized in that, Includes the following steps: Step S1, coordinate transformation: Open the MatlabAPP. In the window interface of the preset coordinate transformation system, fill in the sample size of the rock structure surface and the number of pixels on each side according to the actual situation. Then select the three-dimensional structure surface point cloud file to be transformed. Convert the coordinate data of the structure surface point cloud obtained by three-dimensional laser scanning into real coordinate data to obtain the real coordinate data file. The converted real coordinate data file is saved in the Matlab path folder. Step S2, generating mating structural surfaces from a single structural surface: Open the MatlabAPP, in the window interface of the preset coordinate transformation system, select the transformed real coordinate data file, generate another structural plane coordinate file that matches the original structural plane based on the real coordinate data file, forming a pair of matching structural plane data files with spatial geometric complementary relationship, and save them in the Matlab path folder; Step S3, file reading: Open the Matlab app, select the 3D structural surface point cloud file you want to read. After selecting the file, Matlab will display the file name in the software interface and add the file to the Matlab path folder. At the same time, the coordinate data in the file will be imported into Matlab. Step S4, parameter calculation: Matlab uses imported coordinate data to calculate the tortuosity, undulation angle, roughness coefficient, relative undulation, and maximum height difference of the structural surface based on the set tortuosity calculation formula, undulation angle calculation formula, roughness coefficient calculation formula, relative undulation, and maximum height difference calculation formula, and displays the calculation results. Step S5, structural plane diagram shown: Matlab uses the imported coordinate data to draw a schematic diagram of the structural surface and displays it on the software interface. The generated schematic diagram includes coordinate axes and color gradients divided by height.
2. The method for calculating rock mass structural surface characteristic parameters and generating mating surfaces based on three-dimensional point clouds according to claim 1, characterized in that, In step S1, the process of constructing the three-dimensional structural surface point cloud file is as follows: Step S1.1, Preparation of rock structural surface samples: Rock structural surface samples are prepared by using natural structural surfaces present in the rock or by artificial splitting or direct shearing experiments, and the rock blocks are processed into the predetermined size; Step S1.2, Acquisition of structural surface point cloud data: A non-contact, high-precision laser scanner is used to measure the surface morphology of rock structures. Based on the principle of pulsed laser ranging, the horizontal azimuth angle between the laser beam and the scanned target is collected. ), vertical pitch angle ( ) and ranging ( Based on the coordinate formula, the three-dimensional coordinates of the target object in the coordinate system can be obtained, and finally a set of spatial points with three-dimensional coordinate (X, Y, Z) information is obtained. The set of spatial points is the point cloud data, which is stored as the three-dimensional structural surface point cloud file of the rock structural surface sample.
3. The method for calculating rock mass structural surface characteristic parameters and generating mating surfaces based on three-dimensional point clouds according to claim 2, characterized in that, In step S1.2, the coordinate formula is: 。 4. The method for calculating rock mass structural surface characteristic parameters and generating mating surfaces based on three-dimensional point clouds according to claim 1, characterized in that, In step S1.2, when processing the scanned point cloud data, to eliminate the distortion effects at the scan boundary or when only local point cloud data of the scanned structural surface needs to be selected, Geomagic Wrap software is used to perform data cropping and coordinate correction operations. The specific process is as follows: Use the left mouse button to draw a selection area in the model view to determine the desired area, or use the rectangular selection tool to select the target area; After selecting the area, right-click and select "Invert Selection" to reverse the selected area. Then, redundant point cloud data within the inverse selection area is deleted, thereby preserving the target structural surface area and removing redundant data at the scan boundary; After the coordinate system is aligned and the cut joint surface is tilted in the scanning coordinate system, coordinate correction is performed to make the joint surface reference plane coincide with the XY plane. The specific operation is as follows: Select the cut joint surface with the left mouse button; if a reference plane exists, select the reference plane as well. In the menu bar, select Features-Plane-Best Fit to generate a fitting plane based on the selected point cloud or reference plane, and use this plane as the new XY plane; The command "Align to Global - Create Pair" aligns the fitted plane with the global XY plane, thereby correcting the coordinates of the joint surface.
5. The method for calculating rock mass structural surface characteristic parameters and generating mating surfaces based on three-dimensional point clouds according to claim 1, characterized in that, In step S3, the three-dimensional structural surface point cloud file includes a real coordinate data file and a matching structural surface data file.
6. The method for calculating rock mass structural surface characteristic parameters and generating mating surfaces based on three-dimensional point clouds according to claim 1, characterized in that, In step S4 The formula for calculating the tortuosity is: ； The formula for calculating the undulation angle is: ； in, The tortuosity in the X direction; The number of profile lines; It is the number of points on the cross-section line; The apparent length of the section line; It is the height at point (i, j); The number of sample points along the X direction for the j-th profile line; The number of profile lines in the X direction; This represents the height value of the i-th sample point; This refers to the scan interval; The roughness coefficient is calculated using the following formula: ； ； ； in, The root mean square of the first derivative of the profile line; L To obtain the profile length; and The coordinates of the points on the profile line; N This represents the total number of sample points; For the roughness of the three-dimensional structural surface; Roughness of each profile line; m The number of profile lines; The formula for calculating the relative undulation is: ； ； The formula for calculating the maximum elevation difference is: ； in, It is the maximum height value of the profile line; Minimum value; The length of the outline line; This represents the number of profile lines in the X direction.
7. A system for calculating rock mass structural surface feature parameters and generating mating surfaces based on three-dimensional point clouds for implementing the method described in any one of claims 1-6, characterized in that, include: This is a MatlabAPP module used to read 3D structural surface point cloud files, generate real coordinate data files, generate mating structural surface data files, generate structural surface tortuosity parameters, generate structural surface undulation angle parameters, generate structural surface roughness coefficient parameters, generate structural surface relative undulation parameters, generate structural surface maximum height difference parameters, and generate structural surface schematic diagrams. This module is used to store 3D structural surface point cloud files, real coordinate data files, and storage modules that work with structural surface data files.