Rock slope internal joint exploration method and system based on multi-element information

Abstract

The application discloses a kind of rock slope internal joint exploration methods based on multiple information, comprising the following steps: S1, the probe device with geological radar and three-dimensional laser scanner is stretched into the well of being previously laid in slope;S2, at different well height, the scanning data of well inner wall is obtained by three-dimensional laser scanner, and the joint radar information in a certain range of well wall is obtained by driving geological radar to rotate one week;S3, the radar information obtained is identified to joint space feature, including the joint that is not perpendicular to well inner wall and the joint that is perpendicular to well inner wall, and the depth of joint and the included angle between joint and well inner wall when not perpendicular can be calculated according to the radar data of multiple adjacent scanning periods;S4, the identified joint space feature is fused with the scanning data of three-dimensional laser scanner, and the rock structure surface containing joint three-dimensional information in corresponding well is drawn.The application can realize three-dimensional exploration of rock slope internal joint.

Description

Technical Field

[0001] This invention relates to the field of geological survey, and in particular to a method and system for detecting internal joints in rock slopes based on multi-source information. Background Technology

[0002] Geological surveys are crucial for formulating national and regional geological work plans, meeting societal needs such as mineral exploration, hydrogeological investigation, and engineering geological surveys, and providing vital data for land development, remediation, planning, and comprehensive development and utilization of marine resources. Geological surveys for rock slope engineering primarily utilize drilling and geophysical methods to investigate joints, fissures, and other information at the slope, thereby understanding its stability.

[0003] Joints are fracture surfaces or cracks formed in rocks under stress, and are structures in which the rocks on both sides of the fracture surface do not undergo significant displacement. However, most current geological survey methods can only detect joint information on the surface of slopes, and the methods for detecting joint development inside slopes are relatively limited. Therefore, there is an urgent need for a technical means that can, to a certain extent, determine the occurrence and scale of joints inside slopes, providing more reliable technical support for slope geological exploration. Summary of the Invention

[0004] The main objective of this invention is to provide a method and system for detecting internal joints in rock slopes based on multi-source information, which can enable the detection of internal joints in rock slopes.

[0005] The technical solution adopted in this invention is:

[0006] A method for detecting internal joints in rock slopes based on multivariate information is provided, including the following steps:

[0007] S1. Insert the probe device equipped with ground-penetrating radar and a three-dimensional laser scanner into the exploration well that has been pre-laid on the slope;

[0008] S2. At different well heights, scan data of the inner wall of the well is obtained by a three-dimensional laser scanner, and radar information of joints within a certain range inside the well wall is obtained by driving the ground-penetrating radar to rotate once.

[0009] S3. The acquired radar information is used to identify the spatial features of joints. The identification process is as follows: If there are three fluctuations in the radar data of the i-th scanning cycle, it indicates that there are joints in the rock mass and the inner wall of the joint well is not vertical. Then, the angle between the joint and the inner wall of the well is calculated based on the radar data, and the depth of the joint is calculated based on the radar data of multiple adjacent scanning cycles. If there is only one fluctuation in the radar data of the i-th scanning cycle, it indicates that there are joints in the rock mass and the inner wall of the joint well is vertical. The depth of the joint is calculated based on the radar data of multiple adjacent scanning cycles.

[0010] S4. The identified joint spatial features are fused with the scanning data of the 3D laser scanner to draw the rock structure surface containing the 3D information of the joints in the corresponding exploration well.

[0011] Following the above technical solution, step S4 specifically involves: establishing a three-dimensional data point cloud model using data from a three-dimensional laser scanner, importing the three-dimensional point cloud model into AutoCAD software to generate an AutoCAD file, and drawing the joint orientation in the AutoCAD file based on all calculated joint information.

[0012] Following the above technical solution, when the joint is not perpendicular to the inner wall of the well, the formula for calculating the joint depth is:

[0013]

[0014] In the formula: z i ε is the joint depth measured in the i-th radar scan cycle; c is the speed of electromagnetic wave propagation in air; t is the two-way travel time of electromagnetic wave propagation in the geological medium; x is the horizontal distance between the center points of the radar transmitting antenna and the receiving antenna; ε r is the relative permittivity of the corresponding rock mass material.

[0015] Following the above technical solution, when the joint is not perpendicular to the inner wall of the well, the angle between the joint and the inner wall of the well measured in the i-th scan is:

[0016]

[0017] In the formula: z i z is the joint depth measured in the i-th radar scan cycle; i-1 is the joint depth measured in the (i-1)th radar scan cycle; h is the height the radar descends in each scan.

[0018] Following the above technical solution, assuming a certain joint undergoes a total of n scans, the angle between the joint and the inner wall of the well is:

[0019]

[0020] The length of this joint is:

[0021]

[0022] Width is:

[0023]

[0024] In the formula: z n b is the joint depth measured in the nth radar scan cycle; i Let be the length of the radar wave fluctuation measured in the i-th scan.

[0025] Following the above technical solution, assuming a joint perpendicular to the inner wall of the well undergoes a total of n scans, and since the length of the joint perpendicular to the inner wall of the well cannot be calculated, assume this joint is a circular plane with a diameter of:

[0026]

[0027] In the formula, b i Let be the length of the radar wave fluctuation measured in the i-th scan.

[0028] This invention also provides a system for detecting internal joints in rock slopes based on multi-source information, comprising:

[0029] The probe device, equipped with a ground-penetrating radar and a 3D laser scanner, is used to extend into a pre-laid well on the slope. At different well heights, the 3D laser scanner acquires scanning data of the inner wall of the well, and the ground-penetrating radar is driven to rotate once to acquire radar information of joints within a certain range inside the well wall.

[0030] The joint spatial feature identification module is used to identify the spatial features of joints in the acquired radar information. The identification process is as follows: If there are three fluctuations in the radar data of the i-th scan cycle, it indicates that there are joints in the rock mass and the inner wall of the joint well is not vertical. Then, the angle between the joint and the inner wall of the well is calculated based on the radar data, and the depth of the joint is calculated based on the radar data of multiple adjacent scan cycles. If there is only one fluctuation in the radar data of the i-th scan cycle, it indicates that there are joints in the rock mass and the inner wall of the joint well is vertical. The depth of the joint is calculated based on the radar data of multiple adjacent scan cycles.

[0031] The fusion module is used to fuse the identified joint spatial features with the scanning data of the 3D laser scanner to draw the rock structure surface containing the 3D information of the joints in the corresponding exploration well.

[0032] According to the above technical solution, the probe device includes a ground-penetrating radar, a rotatable support structure, a power structure, and a three-dimensional laser scanner. The ground-penetrating radar is installed on the rotatable support structure. When the probe device is inserted into the well, the rotatable support structure drives the ground-penetrating radar to rotate around the device under the drive of the power structure. The ground-penetrating radar completes a full rotation to scan the well wall and obtain the information behind the wall at the current depth. At the current depth, the lens of the three-dimensional laser scanner rotates to scan the inner wall of the well.

[0033] According to the above technical solution, the main body of the rotatable bearing mechanism includes two clamps, upper and lower, which are welded together in the middle by a cylindrical structure. A large inner diameter cylindrical structure is then sleeved on the outside of the cylindrical structure. The lower part of the large inner diameter cylindrical structure has teeth that mesh with the power gear of the power mechanism. A clamping device is welded to the upper part of the large inner diameter cylindrical structure, on which a ground-penetrating radar is clamped.

[0034] According to the above technical solution, the power mechanism is protected by a metal shell. The power mechanism includes a small motor, which drives a rotatable load-bearing mechanism through a power gear.

[0035] The beneficial effects of this invention are as follows: This invention simultaneously acquires three-dimensional laser scanning information and ground-penetrating radar information within the well, then identifies joint spatial features based on the ground-penetrating radar information, and finally fuses the two information sets to draw joint information in a three-dimensional point cloud model, thus enabling the exploration of joints within rock slopes. Furthermore, this patent is the first to propose a method for identifying the spatial features of back-wall joints based on radar signal waveforms, and classifies back-wall joints into two types: vertical and non-perpendicular to the well wall, calculating the characteristic information of each joint separately.

[0036] Furthermore, this patent employs a combination of drilling and geophysical exploration methods to expand the scope of exploration for joint information within the slope. It utilizes an integrated probe carrying multiple exploration equipment, including ground-penetrating radar and a mobile 3D laser scanner, to collect various data in a single exploration. Moreover, the equipment can be changed according to different working conditions to complete different tasks. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1A This is a schematic diagram illustrating the scenario in which the multi-source information-based rock slope internal joint detection system of this invention is used;

[0039] Figure 1B This is a schematic diagram of the probe device for detecting internal joints in slopes according to an embodiment of the present invention. Figure 1A Part A of the text);

[0040] The components include: 1. Ground-penetrating radar; 2. Probe device; 3. Rotatable support mechanism (clamping ground-penetrating radar part); 4. Power mechanism; 5. Rotatable support mechanism (power transmission part); 6. Mobile 3D laser scanner.

[0041] Figure 2 This is a schematic diagram of the power mechanism according to an embodiment of the present invention;

[0042] Among them: 7. Small motor; 8. Drive gear; 9. Transmission gear.

[0043] Figure 3 This is a schematic diagram of the rotatable bearing mechanism according to an embodiment of the present invention;

[0044] Among them: 10. Upper clamp; 11. Internal cylindrical structure; 12. External cylindrical structure; 13. Lower clamp;

[0045] Figure 4 This is a vertical cross-sectional view of an exploration well according to an embodiment of the present invention;

[0046] Among them: 14. Inner wall of the exploration well; 15. Joints not perpendicular to the inner wall of the exploration well; 16. Joints perpendicular to the inner wall of the exploration well.

[0047] Figure 5 This is the radar signal mode in this embodiment of the invention when the joints are not perpendicular to the well wall;

[0048] Wherein: 17. First signal fluctuation; 18. Second signal fluctuation; 19. Third signal fluctuation; 20. i-th scan cycle; 21. (i+1)-th scan cycle.

[0049] Figure 6 This is the radar signal pattern when the joint is perpendicular to the well wall in this embodiment of the invention;

[0050] Where: 22. The i-th scan cycle; 23. The (i+1)-th scan cycle.

[0051] Figure 7 This is a schematic diagram illustrating the calculation of relevant information when the joint is not perpendicular to the well wall in an embodiment of the present invention;

[0052] Among them: 24. Joints not perpendicular to the well wall.

[0053] Figure 8 This is a schematic diagram of the three-dimensional point cloud model constructed in an embodiment of the present invention (a model for displaying joint information on the wall surface and behind the wall);

[0054] Among them: 25. 3D point cloud model of exploration well; 26. 3D point cloud model of joint;

[0055] Figure 9 This is a technical roadmap for the method of detecting internal joints in rock slopes based on multi-source information, according to an embodiment of the present invention.

[0056] Figure 10 This is a flowchart of a method for detecting internal joints in rock slopes based on multi-source information, according to an embodiment of the present invention. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0058] It should be noted that the illustrations provided in the embodiments of the present invention are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0059] In this invention, it should also be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used only for descriptive and distinguishing purposes and should not be construed as indicating or implying relative importance.

[0060] Example 1

[0061] like Figure 10 As shown, the method for detecting internal joints in rock slopes based on multi-source information in this embodiment mainly includes the following steps:

[0062] S1. Insert the probe device equipped with ground-penetrating radar and a three-dimensional laser scanner into the exploration well that has been pre-laid on the slope;

[0063] S2. At different well heights, scan data of the inner wall of the well is obtained by a three-dimensional laser scanner, and radar information of joints within a certain range inside the well wall is obtained by driving the ground-penetrating radar to rotate once.

[0064] S3. The acquired radar information is used to identify the spatial features of joints. The identification process is as follows: If there are three fluctuations in the radar data of the i-th scanning cycle, it indicates that there are joints in the rock mass and the inner wall of the joint well is not vertical. Then, the angle between the joint and the inner wall of the well is calculated based on the radar data, and the depth of the joint is calculated based on the radar data of multiple adjacent scanning cycles. If there is only one fluctuation in the radar data of the i-th scanning cycle, it indicates that there are joints in the rock mass and the inner wall of the joint well is vertical. The depth of the joint is calculated based on the radar data of multiple adjacent scanning cycles.

[0065] S4. The identified joint spatial features are fused with the scanning data of the 3D laser scanner to draw the rock structure surface containing the 3D information of the joints in the corresponding exploration well.

[0066] Further, step S4 specifically involves: establishing a three-dimensional data point cloud model using data from a three-dimensional laser scanner, importing the three-dimensional point cloud model into AutoCAD software to generate an AutoCAD file, and drawing the joint orientation in the AutoCAD file based on all calculated joint information.

[0067] Specifically, when the joint is not perpendicular to the inner wall of the well, the formula for calculating the joint depth is:

[0068]

[0069] In the formula: z i ε is the joint depth measured in the i-th radar scan cycle; c is the speed of electromagnetic wave propagation in air; t is the two-way travel time of electromagnetic wave propagation in the geological medium; x is the horizontal distance between the center points of the radar transmitting antenna and the receiving antenna; ε r is the relative permittivity of the corresponding rock mass material.

[0070] In a preferred embodiment, when the joint is not perpendicular to the inner wall of the well, the angle between the joint and the inner wall of the well measured in the i-th scan is:

[0071]

[0072] In the formula: z i z is the joint depth measured in the i-th radar scan cycle; i-1 is the joint depth measured in the (i-1)th radar scan cycle; h is the height the radar descends in each scan.

[0073] Assuming a joint undergoes a total of n scans, the angle between the joint and the well wall is:

[0074]

[0075] The length of this joint is:

[0076]

[0077] Width is:

[0078]

[0079] In the formula: z n b is the joint depth measured in the nth radar scan cycle; i Let be the length of the radar wave fluctuation measured in the i-th scan.

[0080] Assume a joint perpendicular to the wellbore's inner wall undergoes n scans. Since the joint's length cannot be calculated, assume it's a circular plane with a diameter of:

[0081]

[0082] In the formula, b i Let be the length of the radar wave fluctuation measured in the i-th scan.

[0083] Example 2

[0084] This embodiment is for implementing the multi-source information-based joint detection system for rock slopes in Embodiment 1, such as... Figure 1A and 1B As shown, the system includes:

[0085] The probe device, equipped with a ground-penetrating radar and a 3D laser scanner, is used to extend into a pre-laid well on the slope. At different well heights, the 3D laser scanner acquires scanning data of the inner wall of the well, and the ground-penetrating radar is driven to rotate once to acquire radar information of joints within a certain range inside the well wall.

[0086] The joint spatial feature identification module is used to identify the spatial features of joints in the acquired radar information. The identification process is as follows: If there are three fluctuations in the radar data of the i-th scan cycle, it indicates that there are joints in the rock mass and the inner wall of the joint well is not vertical. Then, the angle between the joint and the inner wall of the well is calculated based on the radar data, and the depth of the joint is calculated based on the radar data of multiple adjacent scan cycles. If there is only one fluctuation in the radar data of the i-th scan cycle, it indicates that there are joints in the rock mass and the inner wall of the joint well is vertical. The depth of the joint is calculated based on the radar data of multiple adjacent scan cycles.

[0087] The fusion module is used to fuse the identified joint spatial features with the scanning data of the 3D laser scanner to draw the rock structure surface containing the 3D information of the joints in the corresponding exploration well.

[0088] The probe device is mainly used for joint exploration inside rock slopes. As shown in Figure 1, the probe device includes a ground-penetrating radar, a rotatable support mechanism, a power mechanism, and a 3D laser scanner. The ground-penetrating radar is mounted on the rotatable support mechanism. When the device is inserted into the well, the rotatable support system drives the ground-penetrating radar to rotate around the device under the drive of the power mechanism. One rotation of the ground-penetrating radar can scan the well wall and obtain information behind the wall at that location.

[0089] First, several exploration wells are set up at the corresponding locations on the slope. Then, probe devices equipped with ground-penetrating radar and 3D laser scanners are inserted into the exploration wells. The 3D laser scanner is used to obtain 3D scanning information of joints on the inner wall of the exploration well. The ground-penetrating radar is used to obtain the location and size of joints within a certain range behind the exploration well wall, forming a joint exploration mode that combines information from the surface of the exploration well wall and information behind the wall.

[0090] like Figure 2 The diagram shows the power mechanism, whose main body is protected by a metal box. Its main structure is a small motor, which is connected to the lower gears of the outer cylindrical structure of the rotatable load-bearing mechanism through two power gears, providing power for the rotation of the load-bearing system.

[0091] like Figure 3 The diagram shows a rotatable bearing mechanism. Its main body consists of two clamps, upper and lower, welded together by a cylindrical structure. An additional cylindrical structure with a larger inner diameter is fitted over the outer clamps. The lower part of the larger inner diameter cylindrical structure has teeth that mesh with the power gear of the power mechanism. A clamping device is welded to the upper part to hold the ground-penetrating radar. When the ground-penetrating radar needs to rotate, the power mechanism is activated, and the motor drives the larger inner diameter cylindrical structure to rotate via the power gear, thus rotating the ground-penetrating radar.

[0092] The 3D laser scanner, protected by a metal casing, is mounted at the end of the device. Its main structure is a mobile 3D laser scanner. During installation, the scanner's lens is aimed at the inner wall of the well. After the entire device is lowered into the well, the 3D laser scanner is turned on, and the lens rotates to scan the well's inner wall. After completing these steps, one scanning cycle is finished. The scan data is saved, and the joint detection device is lowered to a certain depth to begin the next scanning cycle.

[0093] The core technology of this method lies in the data processing approach of the rock slope internal joint detection device based on multi-source information. The device uses a 3D laser scanner to establish a 3D point cloud model, which is then used to investigate the attitude of joint surfaces on the inner wall of the well. A 3D point cloud model is then created and imported into AutoCAD software to generate an AutoCAD file. Next, based on the acoustic signals acquired by ground-penetrating radar behind the well wall, and according to the proposed joint spatial feature identification method and joint size calculation formula, the attitude and location data of the rock mass joints behind the well wall are obtained. Finally, based on the relevant data, the joints are drawn in the AutoCAD file generated from the point cloud model, thus realizing the detection of joints inside the rock slope.

[0094] Previous processing and analysis of ground-penetrating radar (GPR) data could only identify the type of defects behind the rock mass, such as cavities, fissures, and water bodies, based on the characteristics of the acoustic signals. This paper proposes a method for identifying the spatial characteristics of joints based on radar signals, thereby determining the distribution type of joints in the rock mass. The joint types are divided into two categories: joints perpendicular to the inner wall of the well and joints not perpendicular to the inner wall of the well.

[0095] When identifying the spatial characteristics of joints using the aforementioned multi-source information-based joint detection system for rock slopes, the analysis first takes any joint surface behind the well wall. When the radar wave reaches the inner wall of the well, the radar signal generates a first fluctuation; when the radar wave reaches the joint surface, the signal generates a second fluctuation; and when the radar wave passes through the joint surface and reaches the next layer of rock medium, the radar signal generates a third fluctuation. If the joint is not perpendicular to the inner wall of the well, such as... Figure 4 As shown, the joint depths detected by the radar waves in the i-th and (i+1)-th scanning cycles are different, resulting in different radar waveforms. Figure 5 As shown, when two adjacent waveforms change, it can be determined that the joint surface is not perpendicular to the inner wall of the well. When the joint is perpendicular to the inner wall of the well, the radar wave cannot pass through the joint surface, resulting in the loss of the second and third signal fluctuations, as shown. Figure 6 As shown, only one radar wave is obtained, and this radar wave does not change with the exploration depth (scanning period). Based on these characteristics, the spatial distribution of joints behind the well wall can be preliminarily determined.

[0096] Assuming the joint is elliptical, calculate its dip angle and dimensions. When the joint is not perpendicular to the well wall, use the proposed formula for calculating the depth of joints inside the rock mass using ground-penetrating radar to calculate the depth of the joint surface from the well wall for each exploration. Calculate the angle between the joint surface and the well wall based on triangle characteristics, and finally take the average value as the angle between the joint and the well wall. Then, calculate the major axis length of the joint surface using the sine formula. The specific method is as follows:

[0097] Calculate the dip angle and dimensions of the joints. When the joints are not perpendicular to the inner wall of the well, the calculation formula for the depth of joints inside the rock mass detected by ground-penetrating radar can be used to determine this.

[0098]

[0099] In the formula: z i — Joint depth (m) measured in the i-th scan;

[0100] c—the speed of electromagnetic waves in air (m / s), usually taken as 300 mm / ns;

[0101] t — the two-way travel time (ns) of electromagnetic waves in the formation medium;

[0102] x — Horizontal distance (m) between the center points of the transmitting antenna and the receiving antenna;

[0103] ε r —The relative permittivity of the material.

[0104] like Figure 7 As shown, the angle between the joint and the inner wall of the well, as measured in the first scan, is:

[0105]

[0106] Where: z1——Joint depth (m) measured in the first scan;

[0107] h — the height (m) descended during each scan.

[0108] The angle between the joint and the inner wall of the well, as measured in the i-th scan, is:

[0109]

[0110] Assuming the joint undergoes a total of n scans, the angle between the joint and the well wall is:

[0111]

[0112] The length of the major axis of this joint is:

[0113]

[0114] The length of the minor axis is:

[0115]

[0116] In the formula: b i — The length of the radar wave (m) measured in the i-th scan;

[0117] Since the length of the major axis of the joint perpendicular to the inner wall of the well cannot be calculated, we assume here that this joint is a circular plane with a diameter of:

[0118]

[0119] Based on the calculated angle between the joint surface and the inner wall of the well, as well as the major and minor axes, the joint surface was plotted onto the AutoCAD file generated from the 3D point cloud model. The result is as follows: Figure 8 As shown.

[0120] The innovation of this invention lies mainly in:

[0121] (1) A combination of drilling and geophysical exploration was adopted to expand the scope of joint information exploration within the slope. A multi-integrated probe was used, which was equipped with ground-penetrating radar and mobile three-dimensional laser scanner. Multiple data were collected in one exploration, and the equipment could be changed according to different working conditions to complete different tasks.

[0122] (2) A preliminary judgment method based on the spatial characteristics of back joints based on radar signal waveforms was proposed. Based on the waveform characteristics obtained from the ground-penetrating radar, back joints can be divided into two types: vertical and non-vertical to the well wall, thus forming a preliminary understanding of back joints.

[0123] (3) Based on the waveform of the ground-penetrating radar signal and the proposed joint size calculation formula, calculate the relevant size and dip angle of the joint, and draw them into the Autocad file generated by the point cloud model according to the obtained parameters, forming a joint information display method that combines surface and back wall information.

[0124] Example 3

[0125] like Figure 9 As shown, this is another embodiment of the present invention, a method for detecting internal joints in rock slopes based on multi-source information.

[0126] First, based on the external survey results of the slope, a well layout plan is designed. The well diameter must meet the minimum radius required for the ground-penetrating radar to rotate around the rotatable bearing mechanism. Wells should be placed in strata with poor geological conditions or well-developed joints and fissures as much as possible. After the wells are laid out, the internal joint detection device is lowered parallel to the well wall to collect ground-penetrating radar data and 3D laser scanning data. The specific operation method of the entire probe device is as follows:

[0127] A. First, turn on the ground-penetrating radar and the mobile 3D laser scanner. Then, insert the device into the well. During the insertion process, ensure that the ground-penetrating radar is basically parallel to the well wall and that the rotation axis of the 3D laser scanner lens is basically aligned with the well axis.

[0128] B. Since the mobile 3D laser scanner can perform continuous scanning, when the device is stationary at the target point for ground-penetrating radar scanning, the 3D laser scanner can be switched to standby mode. The 3D laser scanner can be started again after the ground-penetrating radar scanning is completed, thus ensuring that the 3D laser scanner and ground-penetrating radar are in a "working alternately" state.

[0129] C. The operation of the ground-penetrating radar requires starting the motor of the power mechanism. The motor drives the ground-penetrating radar to rotate. After one rotation, the back wall information scan of that point is completed. The ground-penetrating radar is then switched to standby mode, and the device continues to probe into the depth of the well to collect information from other points.

[0130] D. The device stops descending just before it reaches the bottom to prevent the 3D laser scanner from being damaged by touching the bottom. The device is then raised and retrieved.

[0131] E. After data acquisition is completed, post-processing is performed, namely, using the data acquired by the 3D laser scanner to establish a point cloud model of the well surface, using the point cloud model to identify the occurrence information of joints on the well wall surface, and importing the obtained point cloud model into AutoCAD software.

[0132] By collecting acoustic signals behind the well wall using ground-penetrating radar, the locations of joints are identified at points of signal anomaly. Assuming the joints are elliptical planes, this paper proposes a method for identifying the spatial characteristics of joints and a formula for calculating joint dimensions. Using this method and formula, the location and orientation data of the joints are obtained, and the corresponding joints are drawn in the AutoCAD file imported from the point cloud model based on the obtained data.

[0133] The data processing method used by the multi-source information-based rock slope internal joint detection device is also a core technology of this device. Based on multi-source information, the device uses a 3D laser scanner to create a 3D point cloud model to investigate the fractures and structural planes on the inner wall of the well. Ground-penetrating radar is used to detect the size and scale of joints behind the well wall. Then, based on the point cloud data model, the joints detected by the ground-penetrating radar are plotted on the point cloud model, creating a 3D point cloud model combining the well wall surface and back wall data, providing a more detailed and intuitive display of the joint orientation information of the rock slope.

[0134] The processing method for back-wall joint information acquired by ground-penetrating radar is as follows:

[0135] A. Based on determining the distribution type of joints in the rock mass, according to Figure 4 As shown, joint types are divided into two categories: joints perpendicular to the inner wall of the well and joints not perpendicular to the inner wall of the well.

[0136] B. Based on the signal characteristics collected by the ground-penetrating radar, the joint type is determined. When the radar wave reaches the inner wall of the well, the radar signal generates the first fluctuation. When the radar wave reaches the joint surface, the signal generates the second fluctuation. When the radar wave passes through the joint surface and reaches the next layer of rock medium, the radar signal generates the third fluctuation. As the device penetrates deeper, the radar signal changes for the two types of joints differ in different scanning batches. When the joint is not perpendicular to the inner wall of the well, the depth of the device will cause the amplitude of the second and third signal fluctuations to change in adjacent scanning batches, such as... Figure 5 As shown; when the joint is perpendicular to the inner wall of the well, the deepening of the device will cause the loss of the second and third signal fluctuations in the second scanning batch, such as... Figure 6 Place.

[0137] C. Calculate the dip angle and dimensions of the joints. When the joints are not perpendicular to the inner wall of the well, the calculation formula for the depth of joints inside the rock mass detected by ground-penetrating radar can be used to determine this.

[0138]

[0139] In the formula: z i — Joint depth (m) measured in the i-th scan;

[0140] c—the speed of electromagnetic waves in air (m / s), usually taken as 300 mm / ns;

[0141] t — the two-way travel time (ns) of electromagnetic waves in the formation medium;

[0142] x — Horizontal distance (m) between the center points of the transmitting antenna and the receiving antenna;

[0143] ε r —The relative permittivity of the material.

[0144] like Figure 7 As shown, the angle between the joint and the inner wall of the well, as measured in the first scan, is:

[0145]

[0146] Where: z1——Joint depth (m) measured in the first scan;

[0147] h — the height (m) descended during each scan.

[0148] The angle between the joint and the inner wall of the well, as measured in the i-th scan, is:

[0149]

[0150] Assuming the joint undergoes a total of n scans, the angle between the joint and the well wall is:

[0151]

[0152] The length of this joint is:

[0153]

[0154] Width is:

[0155]

[0156] In the formula: b i — The length of the radar wave (m) measured in the i-th scan;

[0157] D. After the calculation is completed, the structural surfaces are drawn in a 3D laser scanner based on the obtained parameters. The result is as follows: Figure 8 As shown.

[0158] E. Since the length of joints perpendicular to the inner wall of the well cannot be calculated, it is assumed here that such joints are circular planes with a diameter of:

[0159]

[0160] b i Let be the length of the radar wave fluctuation measured in the i-th scan.

[0161] F. Repeat step D to draw the structural planes.

[0162] In summary, this invention first deploys exploratory wells at corresponding locations on the slope, and uses a designed and developed joint detection device to collect joint information within the wells. The device's probe is equipped with a mobile 3D laser scanner and a ground-penetrating radar. The scanning lens of the mobile 3D laser scanner faces the inner wall of the well to scan the well wall; the ground-penetrating radar detects joint information behind the wall. A 3D point cloud model is built using the data collected by the 3D laser scanner. Then, based on the acoustic signals obtained from behind the well wall by the ground-penetrating radar, and according to the proposed joint spatial feature identification method and joint size calculation formula, the attitude and location data of the rock mass joints behind the well wall are obtained. Finally, based on the relevant data, the joints are drawn in the point cloud model, realizing the detection of joints inside the rock slope.

[0163] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0164] The order of the steps in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0165] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for detecting internal joints in rock slopes based on multivariate information, characterized in that, Includes the following steps: S1. Insert the probe device equipped with ground-penetrating radar and a three-dimensional laser scanner into the exploration well that has been pre-laid on the slope; S2. At different well heights, scan data of the inner wall of the well is obtained by a three-dimensional laser scanner, and radar information of joints within a certain range inside the well wall is obtained by driving the ground-penetrating radar to rotate once. S3. The acquired radar information is used to identify the spatial features of joints. The identification process is as follows: If there are three fluctuations in the radar data of the i-th scanning cycle, it indicates that there are joints in the rock mass and the inner wall of the joint well is not vertical. Then, the angle between the joint and the inner wall of the well is calculated based on the radar data, and the depth of the joint is calculated based on the radar data of multiple adjacent scanning cycles. If there is only one fluctuation in the radar data of the i-th scanning cycle, it indicates that there are joints in the rock mass and the inner wall of the joint well is vertical. The depth of the joint is calculated based on the radar data of multiple adjacent scanning cycles. S4. The identified joint spatial features are fused with the scanning data of the 3D laser scanner to draw the rock structure surface containing the 3D information of the joints in the corresponding exploration well.

2. The method for detecting internal joints in rock slopes based on multi-source information according to claim 1, characterized in that, Step S4 specifically involves: establishing a three-dimensional point cloud model using data from a three-dimensional laser scanner, importing the three-dimensional point cloud model into AutoCAD software to generate an AutoCAD file, and drawing the joint orientation in the AutoCAD file based on all calculated joint information.

3. The method for detecting internal joints in rock slopes based on multi-source information according to claim 1, characterized in that, When the joint is not perpendicular to the inner wall of the well, the formula for calculating the joint depth is: In the formula: z i ε is the joint depth measured in the i-th radar scan cycle; c is the speed of electromagnetic wave propagation in air; t is the two-way travel time of electromagnetic wave propagation in the geological medium; x is the horizontal distance between the center points of the radar transmitting antenna and the receiving antenna; ε r is the relative permittivity of the corresponding rock mass material.

4. The method for detecting internal joints in rock slopes based on multi-source information according to claim 1, characterized in that, When the joint is not perpendicular to the inner wall of the well, the angle between the joint and the inner wall of the well measured in the i-th scan is: In the formula: z i z is the joint depth measured in the i-th radar scan cycle; i-1 is the joint depth measured in the (i-1)th radar scan cycle; h is the height the radar descends in each scan.

5. The method for detecting internal joints in rock slopes based on multi-source information according to claim 4, characterized in that, Assuming a joint undergoes a total of n scans, the angle between the joint and the well wall is: The length of this joint is: Width is: In the formula: z n b is the joint depth measured in the nth radar scan cycle; i Let be the length of the radar wave fluctuation measured in the i-th scan.

6. The method for detecting internal joints in rock slopes based on multi-source information according to claim 1, characterized in that, Assume a joint perpendicular to the wellbore's inner wall undergoes n scans. Since the joint's length cannot be calculated, assume it's a circular plane with a diameter of: In the formula, b i Let be the length of the radar wave fluctuation measured in the i-th scan.

7. A system for detecting internal joints in rock slopes based on multi-source information, characterized in that, include: The probe device, equipped with a ground-penetrating radar and a 3D laser scanner, is used to extend into a pre-laid well on the slope. At different well heights, the 3D laser scanner acquires scanning data of the inner wall of the well, and the ground-penetrating radar is driven to rotate once to acquire radar information of joints within a certain range inside the well wall. The joint spatial feature identification module is used to identify the spatial features of joints in the acquired radar information. The identification process is as follows: If there are three fluctuations in the radar data of the i-th scan cycle, it indicates that there are joints in the rock mass and the inner wall of the joint well is not vertical. Then, the angle between the joint and the inner wall of the well is calculated based on the radar data, and the depth of the joint is calculated based on the radar data of multiple adjacent scan cycles. If there is only one fluctuation in the radar data of the i-th scan cycle, it indicates that there are joints in the rock mass and the inner wall of the joint well is vertical. The depth of the joint is calculated based on the radar data of multiple adjacent scan cycles. The fusion module is used to fuse the identified joint spatial features with the scanning data of the 3D laser scanner to draw the rock structure surface containing the 3D information of the joints in the corresponding exploration well.

8. The rock slope internal joint detection system based on multi-source information according to claim 7, characterized in that, The probe device includes a ground-penetrating radar, a rotatable support structure, a power structure, and a 3D laser scanner. The ground-penetrating radar is mounted on the rotatable support structure. When the probe device is inserted into the well, the rotatable support structure drives the ground-penetrating radar to rotate around the device under the drive of the power structure. The ground-penetrating radar completes a full rotation to scan the well wall and obtain the information behind the wall at the current depth. At the current depth, the lens of the 3D laser scanner rotates to scan the inner wall of the well.

9. The rock slope internal joint detection system based on multi-source information according to claim 7, characterized in that, The main body of the rotatable bearing mechanism includes two clamps, upper and lower, which are welded together in the middle by a cylindrical structure. A large inner diameter cylindrical structure is then fitted onto the outside of the cylindrical structure. The lower part of the large inner diameter cylindrical structure has teeth that mesh with the power gear of the power mechanism. A clamping device is welded to the upper part of the large inner diameter cylindrical structure, on which a ground-penetrating radar is clamped.

10. The rock slope internal joint detection system based on multi-source information according to claim 7, characterized in that, The power mechanism is protected by a metal casing. The power mechanism includes a small motor that drives a rotatable load-bearing mechanism via a power gear.

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