Method for accurately obtaining complex structural rock mass structure and anisotropy characteristics thereof
By acquiring images within typical areas of rock mass structural features and performing binarization processing, combined with DIP technology and numerical calculation models, the problem of accurately acquiring the structural features of complex rock masses was solved, enabling precise simulation of rock mass mechanical parameters and ensuring the safety of engineering construction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- POWERCHINA HUADONG ENG CORP LTD
- Filing Date
- 2022-06-23
- Publication Date
- 2026-05-01
AI Technical Summary
Existing technologies are insufficient to accurately obtain the structural characteristics and anisotropic properties of complex rock masses, which affects the accuracy of obtaining rock mass mechanical parameters and engineering design.
By delineating measurement windows within typical areas of rock mass structure characteristics, rock mass structure information images are acquired and binarized. DIP technology is used to identify rock mass structure, establish numerical calculation models, adjust mechanical parameters to simulate rock mass stress-strain curves and failure modes, and analyze anisotropic characteristics.
It enables accurate acquisition of the anisotropic characteristics of complex structural rock masses, provides reliable data for engineering construction, and ensures construction safety and the safety of workers' lives and property.
Smart Images
Figure CN115357964B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for accurately obtaining the structure and anisotropic characteristics of complex rock masses. It is applicable to the field of rock mass engineering technology. Background Technology
[0002] In rock engineering, rock mass is defined as a heterogeneous, discontinuous, and anisotropic geological body composed of rocks containing various structural planes within a specific engineering project. Because rock masses are formed over long geological periods, they possess corresponding structures and textures, and are closely related to the specific rock engineering work.
[0003] For rock mass engineering, obtaining the structural characteristics of the rock mass is a crucial prerequisite for accurately acquiring its mechanical parameters and a vital foundation for rock mass engineering design, construction, and safety and stability evaluation. Therefore, the primary task in practical rock mass engineering is to study the structural characteristics of the rock mass, that is, to determine the mechanical and engineering geological features of the rock mass structural planes. Here, the accurate acquisition and geometric description of the rock mass structure plays a vital role in understanding the engineering rock mechanics, hydraulics, and stability characteristics.
[0004] However, how the fracture network and geometric characteristics of engineering rock masses affect their mechanical properties remains an ongoing research question. In this context, accurately acquiring the structural characteristics of complex rock masses is particularly important. However, current methods for obtaining rock mass structural information mostly provide simplified structural features based on field investigations, falling short of the requirements for accurately acquiring comprehensive rock mass structural information. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to provide an accurate method for obtaining the structure and anisotropic characteristics of complex rock masses, in view of the above-mentioned problems.
[0006] The technical solution adopted in this invention is: a method for accurately obtaining the structure and anisotropic characteristics of complex rock masses, characterized in that:
[0007] Identify typical regions that represent the structural characteristics of complex rock masses, and include representative information on this type of rock mass engineering within these regions;
[0008] Delineate the measurement window for obtaining rock mass structure information within the typical area of rock mass structure characteristics;
[0009] Acquire window images of rock mass structure information;
[0010] The rock mass structure within the rock mass structure information window image is identified, the window image is binarized, and then the rock mass structure information is accurately identified based on the binarized image.
[0011] The main rock mass structures within the rock mass structure information window image are statistically analyzed, and the relationship between rock mass structure and graphic color is established.
[0012] The experiment determined the mechanical properties of the main rock mass structure within the measurement window image;
[0013] The binarized rock mass image is imported into the DIP processing software. The DIP processing software performs color recognition and determines the rock mass structure on the rock mass based on the relationship between the rock mass structure and the graphic color. Based on the mechanical properties of the rock mass structure determined by the experiment, the mechanical parameters of the identified rock mass structure on the rock mass are assigned values, and multiple different numerical calculation models are constructed.
[0014] By comparing the stress-strain curves and failure modes of rock mass obtained from numerical simulation and laboratory tests using the numerical calculation model, and by adjusting the parameters of the numerical calculation model, a curve that is basically consistent with the failure mode of the laboratory tests was obtained.
[0015] Numerical calculation models with different inclination angles were tested to obtain the mechanical properties and failure modes under different inclination angle conditions;
[0016] Based on the brittle failure characteristics of the rock mass, the mechanical boundary conditions of the numerical calculation model are determined;
[0017] Based on the numerical analysis results, the typical mechanical parameters of different numerical calculation models are determined;
[0018] Analyze the anisotropic characteristics of the numerical calculation model and provide the variation curves.
[0019] The acquisition of rock mass structure information window images includes: using a digital imaging system or a CT scanning system to acquire images of complex rock mass structures.
[0020] The main rock mass structures within the rock mass structure information window image are statistically analyzed, including the shape of the rock block structure, the direction and number of joint surfaces, and the orientation and dip angle of micro-fractures.
[0021] The numerical calculation models with different tilt angles were tested to obtain the mechanical properties and failure modes under different tilt angle conditions. This included: making models at 10° intervals, and making a total of 10 models from 0° to 90°.
[0022] The beneficial effects of this invention are as follows: This invention acquires measurement windows of complex structural rock masses, then performs statistical analysis on the relevant structures within the measurement windows, selects representative areas for binarization processing, and further distinguishes different rock mass structures based on the binarization results. The binarized images are imported into digital image processing (DIP) software, and mechanical parameters of different structures are assigned according to experimental results. Numerical calculation models in different directions are then created, and the mechanical boundary conditions of the numerical calculation models are set. Typical mechanical parameters of different models are determined based on the numerical analysis results. Finally, the anisotropic characteristics of the numerical calculation models are analyzed, and variation curves are plotted. Based on this, the anisotropic characteristics of complex structural rock masses can be accurately acquired, thereby solving practical problems in engineering and providing protection for normal construction and the safety of workers' lives and property. Attached Figure Description
[0023] Figure 1 This is a flowchart illustrating the method for accurately acquiring complex structural rock masses and their anisotropic characteristics, as provided in an embodiment of the present invention.
[0024] Figure 2 The structural features of complex rock masses and schematic diagrams of various structures within the measurement window are provided for embodiments of the present invention.
[0025] Figure 3 The digital image within the measurement window and the digital model identified based on DIP technology are provided in the embodiments of the present invention.
[0026] Figure 4 The stress-strain curves and failure modes of columnar jointed rock mass provided in the embodiments of the present invention.
[0027] Figure 5 Shear stress-strain curves of a numerical model of columnar jointed rock mass provided in an embodiment of the present invention.
[0028] Figure 6 Numerical simulation results of the structural surface at different included angles provided for embodiments of the present invention include elastic modulus, maximum principal stress, and acoustic emission.
[0029] Figure 7 The stress-strain curves of the model including microcracks and structural planes, the model not including microcracks and structural planes, and the general model provided for embodiments of the present invention are shown.
[0030] Figure 8 The anisotropy of peak intensity, Poisson's ratio, etc., provided in the embodiments of the present invention. Detailed Implementation
[0031] like Figure 1As shown in the figure, this embodiment is a method for accurately obtaining the structure and anisotropic characteristics of complex rock masses, specifically including the following steps:
[0032] Step 101: Identify typical regions that can represent the structural characteristics of complex rock masses.
[0033] An engineering geological survey is conducted on the area from which rock mass structural information is to be obtained. A typical area representing the structural characteristics of complex rock masses is selected. Within this area, representative information of this type of rock mass engineering should be included, such as structural planes, joints, and fissures. In this embodiment, columnar jointed rock mass is selected, which contains micro-cracks and structural planes that are irregularly distributed.
[0034] Step 102: Delineate the measurement window for obtaining rock mass structure information within the typical rock mass structure characteristic area.
[0035] In this embodiment, the size of the rock mass structure feature measurement window is selected as 2.0m × 2.0m. (Illustration of the sampling window) Figure 2 In diagram 'a', the white dashed lines represent columnar joint structures, the solid white lines are prism lines of rock columns, and the solid blue lines within the rock columns are micro-cracks and structural planes. Figure 2 b is with Figure 2 A detailed schematic diagram of the corresponding measuring window. Within the measuring window, the horizontal centerline is used as a baseline to calculate the diameter of the rock column passing through the centerline.
[0036] Step 103: Image acquisition of typical rock mass structure information window.
[0037] During the acquisition of typical rock mass structure information window images, it is essential to ensure the clarity of the acquired image information to meet the requirements for clearly identifying the rock mass structure. If the measurement window for rock mass structure information is too large and does not meet the requirements of single-frame photography, a multi-frame stitching method can be used to acquire relevant images of a large-size measurement window.
[0038] In this embodiment, a measurement window of 2.0m x 2.0m is selected, and a digital imaging system or a CT scanning system can be used to acquire images of complex rock masses.
[0039] Step 104: Identify the rock mass structure within the rock mass structure information window image.
[0040] First, the windowed image is binarized, and then the rock mass structure information is accurately identified based on the binarized image.
[0041] In this embodiment, DIP technology is used to identify and classify the color information of pixels in the obtained digital image, that is, to process the pixels into a set of integer variables, and finally to divide the digital image into square units or grids.
[0042] Step 105: Statistical analysis of the main rock mass structures within the rock mass structure information window image.
[0043] After identifying the relevant structures in the rock mass structure information window, the main rock mass structures are statistically analyzed, including the shape of the rock block structure, the direction and number of joint surfaces, and the orientation and dip angle of microcracks.
[0044] In digital images, these major rock mass structures are displayed in different colors, making them easily distinguishable during pixel recognition and classification. Therefore, this embodiment establishes a relationship between rock mass structure and color to differentiate materials and parameters in numerical simulations. Figure 3 As shown in Figure a, solid blue lines represent microcracks and structural surfaces, while solid black lines represent columnar joints. Digital processing using DIP technology yields the following results: Figure 3 As shown in b.
[0045] Steps 106 and 107 determine the mechanical properties of the main rock mass structure within the measured image, including:
[0046] Step 106: Determine the mechanical properties of rock blocks within the rock mass structure. Obtain rock block structures within typical natural rock mass structures and prepare them into standard-sized rock cores, with dimensions of φ50mm × 100mm. Perform uniaxial compression tests on the standard-sized rock block samples to obtain their typical mechanical properties such as elastic modulus, strength, and Poisson's ratio. Figure 4 The failure modes and stress-strain curves of five standard-sized specimens are presented.
[0047] Step 107: Determine the mechanical properties of the structural planes in the rock mass structure. From the rock mass structure information, obtain the natural rock mass structural planes and prepare standard-sized natural rock mass structural plane specimens. Conduct shear mechanics tests on the natural rock mass structural plane specimens to obtain their shear strength, shear modulus, and other shear mechanics characteristics. In this embodiment, a model with dimensions of 250mm x 250mm is selected, and the mechanical parameters of the columnar joints are continuously adjusted to calculate the shear strength until a suitable shear strength is simulated. (Reference) Figure 5 .
[0048] Step 108: Import the binarized rock mass sample into the DIP processing software.
[0049] Digital images of rock samples are obtained, and the binarized images are imported into DIP (Digital Image Processing) software for color recognition. Here, the DIP software for rock mass structure must accurately identify the rock mass structure based on the pixel colors of the image. This involves processing pixels into a set of integer variables in grayscale space and finally segmenting the digital image into square cells or a grid. In numerical simulation, the grid is directly mapped to the required cells. Different colors are displayed in the digital image, allowing for clear differentiation during pixel recognition and classification. Based on this, the relationship between the established rock mass structure and the graphic colors is used to distinguish materials and parameters in the numerical simulation. The mechanical parameters of the identified rock mass structure are assigned values based on the experimentally determined mechanical properties of the rock mass, thus constructing multiple different numerical calculation models.
[0050] refer to Figure 3 The color information contained in the digital image is distinguished based on the changes in structural feature I, and the median value I of two adjacent different color structures is taken as the threshold for distinguishing different structures.
[0051] Step 109: Determine the mechanical parameters of different structures based on the test results.
[0052] The structure of columnar jointed rock masses mainly includes basalt columns, columnar joints, columnar microcracks, and structural planes. Verifying and determining the mechanical parameters of the structure is a necessary prerequisite for obtaining reliable numerical simulation results; therefore, it is necessary to determine the mechanical parameters of the columnar jointed rock mass.
[0053] This embodiment compares the stress-strain curves and failure modes of columnar jointed rock masses obtained from numerical simulation and laboratory tests using a numerical calculation model. A trial-and-error method is then employed to obtain the mechanical parameters of the columnar jointed rock mass. Furthermore, it ensures that the model sizes for the numerical simulation and laboratory tests are identical. By continuously adjusting the parameters in the numerical simulation examples, a curve that is essentially consistent with the failure mode in the laboratory tests is obtained, and this curve is then used for further numerical simulation.
[0054] In this embodiment, to analyze the influence of structural complexity on the mechanical properties of rock mass, three sets of models, A, B, and C, were created. Model A specifically considered the main characteristics of columnar jointed rock mass, including columnar joints, columnar microcracks, and columnar structural planes. Model B excluded some structures, such as microcracks and structural planes. By comparing models A and B, the mechanical and failure characteristics of columnar jointed rock mass were studied. Model C, based on model B, used straight lines to replace columnar joints. By comparing models B and C, the influence of the structural characteristics of columnar jointed rock mass on its mechanical and failure characteristics can be analyzed.
[0055] Step 110: Create numerical calculation models in different directions.
[0056] After determining the mechanical parameters of different structures, it is necessary to test the numerical calculation models with different inclination angles to obtain the mechanical properties and failure modes under different inclination angle conditions. When selecting the simulation area, the angle α between the longitudinal direction of the rock column and the loading direction is used as a reference.
[0057] In this embodiment, to understand the mechanical properties and failure characteristics of columnar jointed rock masses under different stress directions, models were created at 10° intervals, resulting in 10 models ranging from 0° to 90°. Figure 6 As shown.
[0058] The purpose of creating models with different included angles is to compare and summarize the failure characteristics of models with different included angles, and to plot the corresponding stress-strain curves. Furthermore, this allows for testing on engineering examples to obtain data suitable for practical engineering applications.
[0059] Step 111: Determine the mechanical boundary conditions of the numerical calculation model.
[0060] Complex rock masses exhibit obvious brittle failure characteristics under pressure. In this embodiment, numerical simulation software is used to simulate the mechanical process of the model, which can simulate the failure process of brittle materials such as rocks. An elastic-brittle damage constitutive model is used to describe the mechanical behavior of rocks during brittle failure.
[0061] After establishing the numerical model of the columnar jointed rock mass, the boundary conditions of the model need to be set according to the brittle failure characteristics of the rock mass. The lower plate is set as a fixed interface, and the upper plate is set as an interface subjected to normal stress. Displacement control can be used to simulate the mechanical boundaries.
[0062] Step 112: Determine the typical mechanical parameters of different models based on the numerical analysis results.
[0063] After setting the mechanical boundary conditions of the numerical calculation model, the shear strength of the joint surface can be calculated by continuously adjusting the mechanical parameters of each columnar joint until the simulated shear strength of the joint surface meets the requirements. Furthermore, different mechanical parameters are calibrated for the defective structure in the simulation, and parameter values are assigned to different structural components in the digital image.
[0064] Step 113: Analyze the anisotropic characteristics of the numerical calculation model and provide the variation curves.
[0065] In this embodiment, three sets of columnar jointed rock mass models, A, B, and C, were established respectively. Models with different angles were created in the preceding process to compare and summarize the failure characteristics of models with different angles, and to plot the corresponding stress-strain curves. This allows for testing on engineering examples to obtain data suitable for practical engineering applications, ensuring the normal construction of the project and protecting the lives and property of workers.
[0066] In this embodiment, a series of curves of columnar jointed rock mass were obtained through numerical simulation. Figure 7 The differences in the stress-strain curves directly reflect the gradual nonlinear effects caused by microcracks and irregular columns during the evolution of soil and rock failure.
[0067] Figure 8 The peak strength of three sets of columnar jointed rock mass models is shown to vary with the included angle α. Significant anisotropy is observed in the peak strength of all three numerical models; that is, the peak strength exhibits a U-shaped change as α increases, reaching its lowest point at α = 30°. It is important to note that the presence of microcracks and irregular columns weakens the directional structure within the rock mass, thereby reducing the directionality of the columnar jointed rock mass. The propagation of microcracks leads to early damage to the columns, and stress concentration occurs during deformation of irregular columns, similarly causing early damage. Therefore, columnar jointed rock masses have lower bearing capacity along the longitudinal direction of the columns, but higher bearing capacity in the transverse direction.
[0068] The elastic modulus decreases monotonically with increasing angle α. This is because the columnar joints in the three columnar joint rock mass models are relatively weak and are the main factor controlling deformation. When the angle α is small, the uniaxial stress of the model is mainly maintained by the strong columnar structure, and the overall deformation of the model is very small. As the angle α gradually increases, the model gradually deforms, and the elastic modulus of the columnar joints becomes relatively low.
[0069] When the included angle is α, the axial strain corresponding to the peak intensity exhibits significant anisotropy with the change in included angle α. Furthermore, the lateral strain and Poisson's ratio show an inverted U-shape with the change in included angle α, which is opposite to the trend of the peak intensity and corresponding strain.
[0070] This embodiment, based on obtaining measurement windows of complex rock masses, performs statistical analysis on relevant structures within the measurement windows, and then selects representative areas for binarization processing. Furthermore, it distinguishes different rock mass structures based on the binarization results. The binarized images are then imported into a numerical calculation program, and mechanical parameters for different structures are assigned according to experimental results. Numerical calculation models in different directions are created, and the mechanical boundary conditions of the numerical calculation models are set. Typical mechanical parameters for different models are determined based on the numerical analysis results. Finally, the anisotropic characteristics of the numerical calculation models are analyzed, and variation curves are plotted. Based on this, the anisotropic characteristics of complex rock masses can be accurately obtained, thereby solving practical problems in engineering and ensuring the normal construction of projects and the safety of workers' lives and property.
[0071] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the foregoing claims.
[0072] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.
Claims
1. A method for accurately obtaining the structure and anisotropic characteristics of complex rock masses, characterized in that: Identify typical regions that represent the structural characteristics of complex rock masses, and include representative information on this type of rock mass engineering within these regions; Delineate the measurement window for obtaining rock mass structure information within the typical area of rock mass structure characteristics; Acquire window images of rock mass structure information; The rock mass structure within the rock mass structure information window image is identified, the window image is binarized, and then the rock mass structure information is accurately identified based on the binarized image. The main rock mass structures within the rock mass structure information window image are statistically analyzed, and the relationship between rock mass structure and graphic color is established. The experiment determined the mechanical properties of the main rock mass structure within the measurement window image; The binarized rock mass image is imported into the DIP processing software. The DIP processing software performs color recognition and determines the rock mass structure on the rock mass based on the relationship between the rock mass structure and the graphic color. Based on the mechanical properties of the rock mass structure determined by the experiment, the mechanical parameters of the identified rock mass structure on the rock mass are assigned values, and multiple different numerical calculation models are constructed. The DIP processing software for rock mass structures must be able to accurately identify rock mass structures based on the pixel colors of images, that is, process pixels into a set of integer variables in grayscale space, and finally divide the digital image into square units or grids. By comparing the stress-strain curves and failure modes of rock mass obtained from numerical simulation and laboratory tests using the numerical calculation model, and by adjusting the parameters of the numerical calculation model, a curve that is basically consistent with the failure mode of the laboratory tests was obtained. Numerical calculation models with different inclination angles were tested to obtain the mechanical properties and failure modes under different inclination angle conditions; Based on the brittle failure characteristics of the rock mass, the mechanical boundary conditions of the numerical calculation model are determined; Based on the numerical analysis results, the typical mechanical parameters of different numerical calculation models are determined; Analyze the anisotropic characteristics of the numerical calculation model and provide the variation curves.
2. The method for accurately obtaining the structure and anisotropic characteristics of complex rock masses according to claim 1, characterized in that, The acquisition of rock mass structure information window images includes: using a digital imaging system or a CT scanning system to acquire images of complex rock mass structures.
3. The method for accurately obtaining the structure and anisotropic characteristics of complex rock masses according to claim 1, characterized in that, The main rock mass structures within the rock mass structure information window image are statistically analyzed, including the shape of the rock block structure, the direction and number of joint surfaces, and the orientation and dip angle of micro-fractures.
4. The method for accurately obtaining the structure and anisotropic characteristics of complex rock masses according to claim 1, characterized in that, The numerical calculation models with different tilt angles were tested to obtain the mechanical properties and failure modes under different tilt angle conditions. This included: making models at 10° intervals, and making a total of 10 models from 0° to 90°.