Modeling method for three-dimensional jointed rock masses with different roughness degrees and penetration degrees

Abstract

The invention discloses a modeling method for three-dimensional jointed rock masses with different roughness degrees and penetration degrees, which comprises the following steps of: 1, setting shape and size parameters of the rock masses, and generating a model space according to the shape and size parameters of the rock masses; step 2, setting joint parameters; and step 3, joint orientation control. And step 4, joint form control. And 5, modeling the residual space as a rock material to obtain a final jointed rock mass model. According to the method, morphological characteristics of real joints can be reflected, the obtained model is more practical, and a more accurate numerical model is provided for subsequent simulation analysis; according to the method, the spatial distribution characteristics of the joint surfaces can be freely controlled, and the analysis of the mechanical characteristics of the rock mass under multi-joint or different joint distribution conditions is facilitated. According to the method, the three-dimensional jointed rock mass model can be conveniently and quickly obtained, and the modeling process can be simplified. And the jointed rock mass model generated each time has non-repeatability, so that the randomness of the jointed rock mass model is ensured.

Description

Technical Field

[0001] The present invention relates to the field of numerical simulation of rock mechanics, and particularly to a three-dimensional jointed rock mass modeling method with different roughness and penetration degrees. Background Art

[0002] Joints, as a kind of macroscopic discontinuous structural plane, widely exist in natural rock masses and have a significant impact on the static and dynamic mechanical properties of rock masses. The research on the mechanical properties of jointed rock masses has always been a research topic that has received much attention. When studying the mechanical properties of jointed rock masses, due to the complex morphology of real joints, certain simplifications or assumptions are usually made in the theoretical and experimental studies of jointed rock masses. There is still a certain gap between the analysis results obtained and the actual stress state of jointed rock masses. Therefore, it is of great significance to propose an analysis method considering the complex morphological characteristics of joints for the study of the mechanical properties of jointed rock masses.

[0003] Numerical simulation is a computer-aided analysis method. By establishing a numerical model of jointed rock masses, the numerical simulation method can intuitively present the stress conditions inside jointed rock masses and play an important auxiliary role in analyzing the mechanical properties of jointed rock masses. Traditional modeling methods use regular thin layers to simulate real joint surfaces, which ignores the complex morphological characteristics of joints and the accuracy of the model needs to be improved. Therefore, it is necessary to study a numerical model modeling method that can reflect the morphological characteristics of joints to improve the accuracy of numerical models. Summary of the Invention

[0004] Aiming at the defects of the above-mentioned numerical model of jointed rock masses, the present invention provides a three-dimensional jointed rock mass modeling method that can control the roughness and penetration degree of joint surfaces, providing a more accurate and refined numerical model for the simulation of jointed rock masses. This method further realizes the control of joint morphology (roughness and penetration degree) on the basis of controlling the orientation (dip direction, dip angle, size, thickness and spacing) of joint surfaces in rock masses.

[0005] To achieve the above object, the technical solution of the present invention is: a three-dimensional jointed rock mass modeling method with different roughness and penetration degrees, wherein the modeling of joint surfaces mainly includes two parts: joint orientation control and joint morphology control, as Figure 1 shown. The specific modeling process is as follows:

[0006] Step 1, set the shape and size parameters of the rock mass, and generate a model space according to the shape and size parameters of the rock.

[0007] Step 2, set joint parameters, including: joint dip direction, dip angle, size, thickness, spacing, penetration degree and other parameters;

[0008] Step 3, joint orientation control. The joint surface is simulated using spatially thin layers that are parallel front and back. The direction and position of the 3D joint surface within the model space are determined based on the dip direction, dip angle, size, thickness, and spacing parameters of the joint. Subsequently, the joint surface is generated according to the orientation parameters and divided into grid cells to obtain a preliminary joint surface model;

[0009] Step 4, joint morphology control. Randomly select areas on the joint surface obtained in Step 3 and make it concave and convex on both sides of the joint surface. The number of concave and convex areas and the degree of concavity and convexity are determined according to the set joint roughness. Subsequently, randomly select grid cells in the model after the concave and convex treatment, and remove the grid cell and the cells within a certain range near it, so that the rock masses in front of and behind the joint surface are connected in some areas, realizing the control of joint penetration;

[0010] Step 5, model the remaining space as rock material to obtain the final jointed rock mass model.

[0011] Preferably, the size of the grid cell should not exceed 1 / 2 of the joint thickness. Excessive grid cell size will affect the accuracy of joint surface modeling.

[0012] The present invention mainly realizes the modeling of the 3D joint surface based on joint orientation control and joint morphology control. The modeling process of the joint surface is as Figure 2 shown. Specifically, joint orientation control is mainly used to control the dip direction, dip angle, size, thickness, and spacing of the joint, as Figure 3 shown. According to the set joint dip direction and dip angle, the normal vector direction of the joint surface can be determined, thereby determining the orientation of the joint surface; according to the set joint size, parameters such as the length and width of the joint surface can be determined; according to the set joint thickness, the thickness of the spatial thin layer used to simulate the joint can be determined; according to the set joint spacing, the distance between multiple parallel joints can be determined. Based on the above parameters, the direction and position of the joint within the model space can be accurately determined, and then the joint surface model is generated and divided into grid cells.

[0013] Specifically, joint morphology control is mainly used to control the roughness and penetration of the joint, as Figure 4 shown. First, perform concave and convex treatment on the joint surface model after joint orientation control. The specific steps of this process are as follows: use a random function to select circular areas on the joint surface, and both the center and radius of the circular areas are generated by the random function; then use the random function to determine the concave and convex direction and concave and convex distance of each area, and displace the grid cells within the area in the set concave and convex direction, where the grid cells near the center point have the largest displacement, and the displacement distance is the set concave and convex distance, and the displacement distance decreases from the center to the surrounding, and the grid cells at the edge of the circular area are not displaced.

[0014] Specifically, the joint surface model after the concavo-convex treatment is further subjected to the penetration degree treatment. The specific steps of this process are as follows: A batch of special units are selected from the grid units constituting the joint surface model with a certain probability; subsequently, these units grow around with a certain probability to obtain new special units. After completing the specified number of growth cycles, all special units are cleared to obtain the final three-dimensional joint surface model. The joint surface processed as above will have penetrating holes, and the hole area represents the connected area of the rock mass. The joint penetration degree is the ratio of the area of the connected area to the total area of the joint surface.

[0015] Compared with the current jointed rock mass modeling methods, the advantage of the solution of the present invention is that it can well control the roughness and penetration degree of joints, enabling it to reflect the morphological characteristics of real joints, and the obtained model is more in line with the actual situation, providing a more accurate numerical model for subsequent simulation analysis.

[0016] The modeling method provided by the present invention can control the dip direction, dip angle and spacing of each joint. Based on this method, the spatial distribution characteristics of the joint surface can be freely controlled, which is conducive to the analysis of the mechanical properties of rock masses with multiple joints or different joint distributions.

[0017] In addition, based on the modeling idea provided by the present invention, parametric modeling of jointed rock masses can be realized. According to this method, a three-dimensional jointed rock mass model can be obtained conveniently and quickly, which helps to simplify the modeling process. At the same time, each generated jointed rock mass model is non-repetitive, ensuring the randomness of the jointed rock mass model. Description of the Drawings

[0018] Figure 1 is the flow chart of the three-dimensional jointed rock mass modeling method;

[0019] Figure 2 is the schematic diagram of three-dimensional joint surface modeling;

[0020] Figure 3 is the schematic diagram of joint orientation control;

[0021] Figure 4 is the schematic diagram of joint morphology control;

[0022] Figure 5 is the three-dimensional jointed rock mass model diagram. Detailed Embodiments

[0023] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present application belong to the scope of protection of the present application.

[0024] The modeling process of the example of the present invention is as follows Figure 1 shown, and the specific implementation process is as follows:

[0025] Step 1: Set the shape and size of the jointed rock mass to generate a model space. In this example, the jointed rock mass model is set as a cube with a side length of 50 mm.

[0026] Step 2: Set the joint parameters. In this example, a rock mass model with a single thin-layer joint is generated. The length and width of the joint are both set to 42 mm, the thickness is 2 mm, and the unit normal vector of the joint surface is (0, 0.45, 0.89), and the joint penetration is 40%. Since there is only a single joint, the joint spacing parameter is not set.

[0027] Step 3: Joint orientation control. First, as shown in (a) of Figure 3 , based on the joint size, thickness, direction parameters set in Step 2 and the set joint position, accurately control the spatial orientation of the joint and generate a joint model; subsequently, as shown in (b) of Figure 3 , divide the joint into grid cells, and the aggregate composed of the joint grid cells is the preliminary joint surface model, as shown in (c) of Figure 3 . Among them, the joint position in this example is set at the center of the cube model, and the size of the grid cells in this example is 0.8 mm.

[0028] Step 4: Joint morphology control. The joint morphology control is as shown in Figure 4 and can be divided into two parts: concavo-convex treatment and penetration treatment.

[0029] The concavo-convex treatment is as shown in (a) of Figure 4 . (a) First, randomly select circular areas on the joint surface. The number of circular areas, the center coordinates and radius size of each area are all generated by a random function. In this example, the number of circular areas is set to 40, the radius value range of the semi-area is 0 - 7 mm, and the radius of each area is randomly selected by the random function within the radius value range. (b) Set the concavo-convex direction and concavo-convex distance of each area. In this example, the concavo-convex direction and concavo-convex distance of each area are set based on the random function, and the set concavo-convex distance range is 0 - 3 mm. (c) Displace the grid cells within the circular area in the concavo-convex direction. Among them, the grid cells near the center point have the largest displacement, and the displacement distance is the set concavo-convex distance. The displacement distance decreases from the center to the surrounding, and the grid cells at the edge of the circular area do not move, thus obtaining a joint model with different roughnesses.

[0030] The penetration treatment is as shown in Figure 4As shown in (b) of , (a) First, randomly select grid cells on the joint surface after concavo-convex treatment, and set this cell as a special cell; (b) Subsequently, set the number of growth cycles, and let the special cell grow in all directions to obtain new special cells. When the number of cycles is reached, the growth stops. In this example, the growth probability in each direction is set to 0.2, and the number of growth cycles is 15; (c) Clear all special cells to achieve the penetration of the rock masses before and after the joint surface. At the same time, judge whether the penetration degree of the processed joint surface meets the requirements. If it does not meet the requirements, repeat the above steps; if it meets the requirements, stop the cycle, and all the remaining grid cells are the final joint surface model.

[0031] Step 5, model the remaining space as rock material to obtain the final jointed rock mass model.

[0032] The core of the present invention is a control method for the roughness and penetration degree of jointed rock masses. Based on the concavo-convex treatment and penetration degree treatment in joint morphology control, the roughness and penetration degree of joints are finely controlled. Compared with the original modeling method, the model generated by the method of the present invention takes into account the morphological distribution characteristics of real joints and has randomness, providing a more accurate model for subsequent numerical simulations.

[0033] The specific implementation methods described above have elaborated in detail the purpose, technical solutions and beneficial effects of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for modeling three-dimensional jointed rock mass with different roughness and penetration, characterized in that: The modeling of joint surface includes two parts: joint orientation control and joint morphology control. The specific modeling process is as follows: Step 1, setting the rock shape and size parameters, and generating the model space according to the rock shape and size parameters; Step 2, setting joint parameters, including: joint inclination, dip, size, thickness, spacing, and penetration parameters; Step 3, joint orientation control: The joint surface is simulated by using a front-to-back parallel space thin layer, and the direction and position of the three-dimensional joint surface in the model space are determined according to the dip, inclination, size, thickness and spacing parameters of the joint; then the joint surface is generated according to the orientation parameters and divided into grid units to obtain a preliminary joint surface model; Step 4, joint morphology control: randomly select areas on the joint surface obtained in step 3 to make concave and convex on both sides of the joint surface, and the number and degree of concave and convex areas are determined according to the set joint roughness; then, randomly select grid cells in the model after concave and convex processing, clear the grid cells and the cells in a certain range nearby, so that the rock mass before and after the joint surface is connected in certain areas, so as to realize the control of joint penetration; Step 5: Model the remaining space as rock material to obtain the final jointed rock mass model.

2. A three-dimensional jointed rock mass modeling method with different roughness and penetration according to claim 1, characterized in that: The size of the grid unit should not exceed 1 / 2 of the joint thickness; a grid unit size that is too large will affect the accuracy of joint surface modeling.

3. A three-dimensional jointed rock mass modeling method with different roughness and penetration according to claim 1, characterized in that: The modeling of three-dimensional joint surfaces is realized based on joint orientation control and joint morphology control. The joint orientation control is used to control the inclination, dip, size, thickness and spacing of the joints. The normal vector direction of the joint surface is determined according to the set joint inclination and dip, thereby determining the orientation of the joint surface. The length and width parameters of the joint surface are determined according to the set joint size. The thickness of the spatial thin layer used to simulate the joints is determined according to the set joint thickness. The distance between multiple parallel joints is determined according to the set joint spacing. Based on the above parameters, the direction and position of the joints in the model space are accurately determined, and then the joint surface model is generated and divided into grid units.

4. A three-dimensional jointed rock mass modeling method with different roughness and penetration according to claim 1, characterized in that: Joint morphology control is used to control the roughness and penetration of joints. First, the joint surface model that has been controlled by joint orientation is subjected to concave-convex processing; the specific steps are as follows: a circular area is selected on the joint surface using a random function, and the center and radius of the circular area are generated by the random function; then the random function is used to determine the concave-convex direction and concave-convex distance of each area, and the grid units in the area are displaced in the set concave-convex direction, among which the grid units near the center of the circle have the largest displacement, and the displacement distance is the set concave-convex distance. The displacement distance decreases from the center of the circle to the surrounding areas, and the grid units at the edge of the circular area are not displaced.

5. A three-dimensional jointed rock mass modeling method with different roughness and penetration according to claim 4, characterized in that: The joint surface model after the concave-convex treatment is processed for connectivity; the specific steps of this process are: a group of special units are selected with a certain probability from the grid units that constitute the joint surface model; then these units are allowed to grow to the surrounding areas with a certain probability to obtain new special units; after completing the specified number of growth cycles, all special units are cleared to obtain the final three-dimensional joint surface model; the processed joint surface will have through holes, and the hole area represents the connected area of ​​the rock mass; the joint connectivity is the ratio of the area of ​​the connected area to the total area of ​​the joint surface.

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