A surrounding rock crack identification and segmented precision grouting system and method based on ultrasonic detection

Abstract

This invention discloses a system and method for identifying and precisely grouting segmented rock fissures based on ultrasonic detection. The system includes a piezoelectric ultrasonic sensor array, a data acquisition unit, a data processing unit, a multi-channel ultrasonic detector, and segmented grouting anchors. The segmented grouting anchors integrate an outer rod, an inner rod, a segmented sealing device, and a pressure control component, enabling segmented and segmented grouting operations in the surrounding rock. This invention acquires surrounding rock wave velocity and amplitude data using ultrasound, employs a joint iterative reconstruction algorithm to invert and construct a fissure model, divides grouting segments according to the surrounding rock strength, matches grouting parameters, and completes precise segmented grouting through the pressure control component. After grouting, secondary ultrasonic detection is used to achieve effect evaluation and closed-loop feedback. This allows for accurate identification of surrounding rock fissures, enabling differentiated grouting, improving anchoring effect and surrounding rock stability, avoiding insufficient or excessive grouting, saving material and engineering costs, and solving the shortcomings of traditional grouting methods such as blind application of parameters and poor reinforcement effect.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering technology, specifically to a system and method for identifying and precisely grouting segmented rock fissures based on ultrasonic detection. Background Technology

[0002] During the construction and long-term operation of underground engineering projects such as tunnel excavation, mining, and slope stabilization, stress redistribution in the surrounding rock, groundwater erosion, and engineering disturbances can easily lead to rock mass fissures, causing problems such as reduced surrounding rock strength, water leakage, and even collapse and instability. Grouting reinforcement is a core technical means to solve these problems, but traditional grouting processes have the following obvious drawbacks: The grouting process is blind and cannot accurately identify the location, opening and development degree of internal cracks in the surrounding rock. It is easy to cause insufficient grouting leading to reinforcement failure, or excessive grouting causing material waste and rock mass splitting. Traditional segmented grouting anchor bolt construction parameter settings rely on experience and cannot be adaptively adjusted according to the actual strength of the surrounding rock, resulting in low precision in grouting pressure and flow control. Ultrasonic detection technology is only used for rock mass quality testing or random inspection after grouting. It does not form a real-time closed-loop linkage with grouting construction, and cannot achieve integrated management and control of detection, grouting and evaluation.

[0003] Existing technologies cannot meet the needs of precise reinforcement of surrounding rock in underground engineering. Therefore, there is an urgent need for a technical solution that integrates ultrasonic non-destructive testing with segmented grouting to achieve precise crack identification, intelligent parameter matching, and closed-loop control of grouting. Summary of the Invention

[0004] The purpose of this invention is to overcome or at least partially solve the above problems by proposing a system and method for identifying surrounding rock fissures and performing segmented precision grouting based on ultrasonic detection.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a rock fissure identification and segmented precision grouting system based on ultrasonic detection, characterized in that it includes a piezoelectric ultrasonic sensor array with a frequency of 50kHz-250kHz, a data acquisition instrument, a data processing unit with a built-in joint iterative reconstruction algorithm, a multi-channel ultrasonic detector, and segmented grouting anchor bolts. The piezoelectric ultrasonic sensor array is connected to the data acquisition instrument via signal connection, and the data acquisition instrument is connected to the data processing unit via signal connection. The segmented grouting anchor bolt includes an outer rod, an inner rod, a grouting hole, an ultrasonic probe, an ultrasonic probe line, a segmented sealing device, and a pressure regulating component. The outer rod of the anchor bolt is a hollow rod body with external threads on its surface and grouting holes distributed axially. The inner rod is coaxially located inside the outer rod and has pipeline holes. The ultrasonic probe is fixed to the inner side of the inner rod and is electrically connected to a multi-channel ultrasonic detector through an ultrasonic probe line passing through the pipeline holes. The multi-channel ultrasonic detector is connected to the display signal. The segmented sealing device is spaced out on the outside of the outer rod of the anchor bolt, and the pressure regulating component is integrated inside the outer rod of the anchor bolt and connected to the grouting channel. The piezoelectric ultrasonic sensor array, data acquisition instrument, and data processing unit work together to complete the detection of surrounding rock fissures and the division and parameter matching of grouting areas. The multi-channel ultrasonic detector and ultrasonic probe work together to complete the detection of surrounding rock before and after grouting. The segmented grouting anchor bolts rely on segmented sealing devices and pressure control components to perform segmented grouting operations.

[0006] Preferably, the inner wall of the grouting channel of the outer anchor rod is uniformly provided with guide ribs along the axial direction. The guide ribs have a semi-circular cross section, which is used to guide the grout to flow uniformly and enhance the structural strength of the outer anchor rod.

[0007] Preferably, the segmented sealing device includes multiple high-pressure resistant and highly elastic rubber ring-shaped sealing elements. The outer diameter of the sealing element is larger than the diameter of the anchor bolt mounting hole, and the inner side is provided with annular anti-slip protrusions for tightly fitting with the inner wall of the borehole to separate and form independent grouting sections.

[0008] Preferably, the pressure regulation component includes a pressure regulating valve, a pressure sensor, a control chip, and a flow sensor; the pressure sensor and the flow sensor are both electrically connected to the control chip, and the control chip is controlled by the electric pressure regulating valve.

[0009] Preferably, the outer end of the anchor rod is sequentially equipped with a grout stop plug, a washer, and a nut; the grout stop plug is a frustoconical rubber component used to seal the grout overflow from the orifice; the washer is a square steel plate with a central hole and is located outside the grout stop plug to evenly distribute the anchoring force; the nut is a high-strength carbon steel component and is threaded into the outer end of the anchor rod to lock and fix the anchor rod.

[0010] Preferably, the multi-channel ultrasonic detector is equipped with a preamplifier, a bandpass filter, and a high-speed data acquisition module, which can perform noise reduction processing on ultrasonic signals and synchronously sample and record waveform data with sub-microsecond precision.

[0011] This invention also provides a method for identifying surrounding rock fractures and performing segmented, precise grouting based on ultrasonic detection, comprising the following steps: A piezoelectric ultrasonic sensor array is deployed to collect ultrasonic travel time and amplitude data of the surrounding rock and transmit them to the data processing unit. The data was inverted using a joint iterative reconstruction algorithm, a rock fissure model was constructed, and the grouting area was divided according to the ultrasonic wave velocity threshold and the grouting parameters were matched. Insert the segmented grouting anchor into the borehole, adjust the segmented sealing device to the corresponding grouting section, and complete the anchor assembly and fixation. Grouting is performed in stages from the bottom of the hole to the opening, and the grouting pressure and flow rate are adjusted in real time by a pressure control component. After grouting, a multi-channel ultrasonic detector is used for secondary detection to assess the grouting effect and supplement grouting as needed.

[0012] Furthermore, grouting zones are divided according to ultrasonic wave velocity. Zones with wave velocities below the first threshold are high-priority grouting zones, those between the first and second thresholds are medium-priority grouting zones, and those above the second threshold are intact rock mass zones, which are then grouted with low-priority grouting or temporarily not grouted.

[0013] Furthermore, during the grouting process, the control chip 17 automatically adjusts the opening of the pressure regulating valve based on real-time pressure and flow signals, thereby achieving independent and precise control of the parameters of each grouting section.

[0014] Furthermore, the grouting effect is quantitatively evaluated by comparing the changes in ultrasonic wave velocity field and attenuation field before and after grouting, forming a closed-loop reinforcement mechanism of detection, zoning, grouting, evaluation, and replenishment.

[0015] Compared with existing technologies, this invention provides a system and method for identifying and precisely grouting segmented rock fissures based on ultrasonic detection, which has the following advantages: By using a multi-channel ultrasonic detector to accurately detect the strength of the surrounding rock at different depths, and dividing the grouting sections according to the detection results, and combining the pressure control component to match the corresponding grouting parameters for different grouting sections, precise grouting of the surrounding rock fissures is achieved. This fundamentally solves the problem of unreasonable grouting caused by single parameters and blind construction in traditional grouting, and greatly improves the grouting effect. The optimal grouting parameters can be adapted to different areas of surrounding rock strength. In areas with low surrounding rock strength, the grout can fully fill internal cracks, significantly enhancing the bond between the anchor bolt and the surrounding rock. In areas with high surrounding rock strength, it can effectively prevent excessive grouting from causing splitting damage to the rock mass, ensuring the anchor bolt anchoring effect. With the synergistic effect of the grout stop plug, gasket, and nut, the connection between the anchor bolt and the surrounding rock is further enhanced, improving the overall anchor bolt anchoring force and the overall stability of the surrounding rock, significantly enhancing the support performance, and providing reliable protection for the long-term safety of underground engineering such as tunnels and mine roadways. By precisely controlling the grouting volume, the waste of materials caused by blind construction in traditional grouting is eliminated. Under the premise of ensuring the quality of support, the cost of engineering materials is effectively reduced. It can also reduce the repair work caused by insufficient support in the later stage, further save construction and operation and maintenance costs, and greatly improve the overall economic benefits of the project. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the segmented grouting anchor installation structure and surrounding rock stratification of the present invention; Figure 2 This is a flowchart illustrating the overall workflow of the present invention. Figure 3 This is a schematic diagram of one arrangement of the ultrasonic sensor array of the present invention in a tunnel cross section; Figure 4 This is a schematic diagram illustrating the segmented division of the surrounding rock grouting according to the present invention; Figure 5 This is a schematic diagram of the overall structure of the grouting rod body of the present invention; Figure 6 This is a schematic diagram of the internal structure of the outer rod of the anchor bolt of the present invention; Figure 7 This is a schematic diagram of the cross-section of the anchor rod body of the present invention; Figure 8 This is a schematic diagram of the pressure regulation component of the present invention.

[0017] In the diagram: 1. Grouting hole; 2. Display; 3. Ultrasonic probe; 4. Outer anchor rod; 5. Inner anchor rod; 6. Grout stop plug; 7. Gasket; 8. Nut; 9. Ultrasonic probe line; 10. Multi-channel ultrasonic detector; 11. Guide rib; 12. Segmented sealing device; 13. Pressure control assembly; 14. Pipeline hole; 15. Pressure regulating valve; 16. Pressure sensor; 17. Control chip; 18. Flow sensor. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the accompanying drawings.

[0019] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this description, those skilled in the art can make creative modifications to this embodiment as needed, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

[0020] This invention provides a system and method for identifying and precisely grouting segmented rock fissures based on ultrasonic detection, which solves the technical problems in the prior art. The overall concept is as follows: Example

[0021] Please see Figures 1-8A system for identifying surrounding rock fissures and performing segmented precision grouting based on ultrasonic detection is proposed. It utilizes piezoelectric ultrasonic sensors with frequencies ranging from 50kHz to 250kHz, arranged in an array along the tunnel's top contour at designed intervals. Equipped with a data acquisition unit and a data processing unit featuring a built-in Joint Iterative Reconstruction Algorithm (SIRT), it achieves full waveform data acquisition, ray tracing inversion, and simultaneous calculation of the surrounding rock wave velocity field and attenuation coefficient. The multi-channel ultrasonic detector 10 incorporates a preamplifier, bandpass filter, and high-speed data acquisition module. After noise reduction and conditioning, the ultrasonic signal is synchronously sampled with sub-microsecond precision, recording the waveform's initial arrival time and amplitude attenuation data, which are then transmitted to the surface host and displayed in real-time on a monitor 2.

[0022] High-strength alloy steel is selected and the hollow tubular outer rod 4 is machined. The outer wall is machined with standard external threads, and grouting holes 1 are evenly and staggered in the circumferential direction along the rod body axis. The inner rod 5 is coaxially machined inside the outer rod 4, and pipeline holes 14 are opened on the outer side. The head of the outer rod 4 is machined into the shape of a ball tooth alloy drill bit, which is convenient for drilling into the surrounding rock. The tail is machined into a connector to match the internal thread of the grouting pipe.

[0023] On the inner wall of the grouting channel of the outer anchor rod 4, semi-circular guide ribs 11 are evenly arranged axially to guide the uniform flow of grout and enhance the structural strength of the rod. A ring-shaped seal is made of high-pressure resistant, high-elasticity rubber using a rubber injection molding process. The outer diameter of the seal is larger than the diameter of the anchor rod installation hole, and annular anti-slip protrusions are machined on the inner side. It is then fitted onto the outer wall of the outer anchor rod 4 with an interference fit, forming an independent grouting section.

[0024] The strain gauge pressure sensor 16, the electromagnetic flow sensor 18, the high-performance microcontroller control chip 17, and the electric pressure regulating valve 15 are integrated and assembled, and installed inside the outer rod 4 of the anchor bolt and connected to the grouting channel to realize real-time monitoring and automatic adjustment of grouting pressure and flow.

[0025] A truncated cone-shaped grout stopper 6 is manufactured using a rubber molding process, with an annular sealing groove machined on its side. A square pad 7 is made by cutting and drilling steel plates. A nut 8 is machined from high-strength carbon steel and matched with the external thread of the outer rod 4 of the anchor bolt. An ultrasonic probe 3 is fixed inside the inner rod 5, and an ultrasonic probe wire 9 passes through the pipeline hole 14, with one end connected to the ultrasonic probe 3 and the other end connected to a multi-channel ultrasonic detector 10, thus completing the integration of the detection system with the anchor bolt.

[0026] In the area of ​​the tunnel to be reinforced, detection boreholes are laid out at intervals along the outline. The ultrasonic probe 3 of the multi-channel ultrasonic detector 10 is placed into the borehole and gradually moved upward from the bottom of the hole to measure and record the ultrasonic wave velocity and amplitude data at different depths. The data is transmitted to the data processing unit via a data acquisition instrument. A joint iterative reconstruction algorithm is used to invert and calculate, generating a surrounding rock wave velocity field and attenuation field model, which is then fused to construct a digital model of the fracture structure. The measurement data is imported into professional software to draw a strength-depth curve. Grouting sections are divided according to wave velocity thresholds. Areas with wave velocities below the first threshold are high-priority grouting areas, areas with wave velocities between the first and second thresholds are medium-priority grouting areas, and areas with wave velocities above the second threshold are intact rock mass areas, which can be temporarily left ungrown or grouted with low priority. At the same time, the grout parameter expert database is called to match the optimal grouting pressure, grout water-cement ratio, and grouting volume for each area. Drill anchor bolt installation holes in the surrounding rock according to the design, insert the assembled segmented grouting anchor bolts into the holes to the designed depth, adjust the position of the segmented sealing device 12 to make it accurately correspond to the divided grouting segments, install the grout stop plug 6 and the pad 7 in sequence at the hole end of the outer rod 4 of the anchor bolt, and tighten the nut 8 to achieve anchor bolt fixation, hole sealing and anchoring force distribution.

[0027] The grouting equipment is connected to the anchor bolt tail connector, and grouting begins from the bottom grouting section. Based on the strength of the surrounding rock in this section, the grouting pressure and grouting volume are set through the pressure control component 13. During the grouting process, the pressure sensor 16 and flow sensor 18 collect data in real time, and the control chip 17 automatically adjusts the opening of the electric pressure regulating valve 15. When the grouting volume and pressure reach the set values ​​and the pressure stabilizes, the grouting of this section is stopped, and the process is switched to the adjacent previous section, and so on, to complete the construction of all grouting sections. After the entire section is grouted, a second detection is performed using a multi-channel ultrasonic detector 10 to compare the changes in the wave velocity field and attenuation field before and after grouting, and to quantitatively evaluate the grouting filling and surrounding rock reinforcement effect. If the preset reinforcement standard is not met, the supplementary grouting process is immediately started until the design requirements are met.

[0028] This invention allows for the pre-reservation of anchor bolt installation holes in key areas during the initial support stage of a tunnel. Guide sleeves are pre-embedded and sealed within the holes for protection. After several years of tunnel operation, the pre-reserved inspection channels are opened, and an ultrasonic sensor array is deployed in the target area to collect ultrasonic data of the surrounding rock. This data is then compared with historical databases to identify the development of cracks and the degradation of strength. If new cracks or insufficient strength are detected in the surrounding rock, the segmented grouting anchor bolts of this invention are inserted through the pre-reserved holes. The above-mentioned detection, zoning, grouting, and evaluation steps are repeated to achieve targeted grouting reinforcement. This enables long-term safety management of tunnel support that is monitorable, maintainable, and reinforceable.

[0029] The above description of the embodiments is provided to facilitate understanding and use of the present invention by those skilled in the art. It is obvious to those skilled in the art that various modifications can be made to the embodiments, and the general principles described herein can be applied to other embodiments without creative effort. Therefore, the present invention is not limited to the above embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A system for identifying surrounding rock fissures and performing segmented precision grouting based on ultrasonic detection, characterized in that, It includes a piezoelectric ultrasonic sensor array, a data acquisition unit, a data processing unit, a multi-channel ultrasonic detector (10), and segmented grouting anchor bolts. The piezoelectric ultrasonic sensor array is connected to the data acquisition instrument via signal connection, and the data acquisition instrument is connected to the data processing unit via signal connection. The segmented grouting anchor bolt includes an outer rod (4), an inner rod (5), a grouting hole (1), an ultrasonic probe (3), an ultrasonic probe line (9), a segmented sealing device (12), and a pressure regulating component (13). The outer rod (4) of the anchor rod is a hollow rod body with external threads on its surface and grouting holes (1) distributed axially. The inner rod (5) is coaxially located inside the outer rod (4) of the anchor rod and has a pipeline hole (14). The ultrasonic probe (3) is fixed inside the inner rod (5) and is electrically connected to the multi-channel ultrasonic detector (10) through the ultrasonic probe line (9) passing through the pipeline hole (14). The multi-channel ultrasonic detector (10) is connected to the display (2) for signal connection. The segmented sealing device (12) is spaced out on the outside of the anchor rod (4), and the pressure regulating component (13) is integrated inside the anchor rod (4) and connected to the grouting channel; The piezoelectric ultrasonic sensor array, data acquisition instrument and data processing unit work together to complete the detection of surrounding rock fissures and the division and parameter matching of grouting areas. The multi-channel ultrasonic detector (10) and ultrasonic probe (3) work together to complete the detection of surrounding rock before and after grouting. The segmented grouting anchor bolts rely on the segmented sealing device (12) and pressure control component (13) to perform segmented grouting operations.

2. The system for identifying and precisely grouting segmented rock fissures based on ultrasonic detection according to claim 1, characterized in that, The inner wall of the grouting channel of the outer rod of the anchor (4) is uniformly provided with guide ribs (11) along the axial direction, and the cross section of the guide ribs (11) is semi-circular.

3. The system for identifying and precisely grouting segmented rock fissures based on ultrasonic detection according to claim 1, characterized in that, The segmented sealing device (12) includes multiple rubber ring seals, the outer diameter of which is larger than the diameter of the anchor bolt mounting hole and the inner side is provided with annular anti-slip protrusions.

4. The system for identifying and precisely grouting segmented rock fissures based on ultrasonic detection according to claim 1, characterized in that, The pressure control component (13) includes a pressure regulating valve (15), a pressure sensor (16), a control chip (17), and a flow sensor (18); the pressure sensor (16) and the flow sensor (18) are both electrically connected to the control chip (17), and the control chip (17) is controlled by the electric pressure regulating valve (15).

5. The system for identifying and precisely grouting segmented rock fissures based on ultrasonic detection according to claim 1, characterized in that, The anchor rod (4) is equipped with a grout stop plug (6), a pad (7) and a nut (8) in sequence at the hole end; the grout stop plug (6) is a truncated cone-shaped rubber part; the pad (7) is a square steel plate with a central hole and is located on the outside of the grout stop plug (6); the nut (8) is a carbon steel part and is threaded to the anchor rod (4).

6. The system for identifying and precisely grouting segmented rock fissures based on ultrasonic detection according to claim 1, characterized in that, The multi-channel ultrasonic detector (10) is equipped with a preamplifier, a bandpass filter and a high-speed data acquisition module, which can perform noise reduction processing on ultrasonic signals and synchronously sample and record waveform data with sub-microsecond precision.

7. A method for identifying surrounding rock fissures and performing segmented precision grouting based on ultrasonic detection, applied to the system described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Deploy a piezoelectric ultrasonic sensor array to collect ultrasonic travel time and amplitude data of the surrounding rock and transmit them to the data processing unit. S2. Use a joint iterative reconstruction algorithm to invert data, construct a surrounding rock fracture model, and divide the grouting area according to the ultrasonic wave velocity threshold and match the grouting parameters. S3. Insert the segmented grouting anchor into the borehole, adjust the segmented sealing device (12) to the corresponding grouting section and complete the anchor assembly and fixing; S4. Grouting is carried out in sections from the bottom of the hole to the opening, and the grouting pressure and flow rate are adjusted in real time by the pressure control component (13); S5. After grouting, a multi-channel ultrasonic detector (10) is used for secondary detection to evaluate the grouting effect and supplement grouting as needed.

8. The method for identifying surrounding rock fissures and performing segmented precise grouting based on ultrasonic detection according to claim 7, characterized in that, Grouting zones are divided according to ultrasonic wave velocity. Zones with wave velocities below the first threshold are high-priority grouting zones, zones with wave velocities between the first and second thresholds are medium-priority grouting zones, and zones with wave velocities above the second threshold are intact rock mass zones and are grouted with low-priority grouting or temporarily not grouted.

9. A method for identifying surrounding rock fissures and performing segmented precise grouting based on ultrasonic detection according to claim 7, characterized in that, During the grouting process, the control chip (17) automatically adjusts the opening of the pressure regulating valve (15) according to the real-time pressure and flow signals, so as to realize independent and precise control of the parameters of each grouting section.

10. A method for identifying surrounding rock fissures and performing segmented precise grouting based on ultrasonic detection according to claim 7, characterized in that, The grouting effect is quantitatively evaluated by comparing the changes in ultrasonic wave velocity field and attenuation field before and after grouting, forming a closed-loop reinforcement mechanism of detection, zoning, grouting, evaluation, and replenishment.

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