A device for detecting micro cracks in underground mass concrete

Abstract

The application discloses a device for detecting small cracks of underground mass concrete and relates to the technical field of concrete crack depth detection devices. The device for detecting small cracks of underground mass concrete comprises an I-shaped frame composed of a main rod and a vice rod, and further comprises frames arranged at two ends of the vice rod respectively, a floating plate arranged in the frame, an ultrasonic probe installed on the floating plate, and a positioning rod connected to the floating plate at one end and extending away from the floating plate at the other end. The ultrasonic probe is installed on the I-shaped frame, different forces are applied to the ultrasonic probe and a surface to be detected by adopting a three-segment type force compression measurement method, and a segmented data acquisition mechanism records crack depth data under different pressures in a one-segment type, a two-segment type and a three-segment type, thereby providing multi-dimensional references for small crack analysis, solving the problem of insufficient data information under single pressure, and effectively improving detection precision.

Description

Technical Field

[0001] This invention belongs to the technical field of concrete crack detection devices, specifically, it relates to a device for detecting micro-cracks in large-volume underground concrete. Background Technology

[0002] Underground large-volume concrete structures (such as subway tunnels, underground utility tunnels, and foundations for water conservancy projects) serve as core load-bearing units in engineering construction, and their structural integrity directly affects the safety and service life of the project. During concrete pouring, curing, and long-term service, micro-cracks are easily generated due to factors such as material shrinkage, temperature stress, and load effects. These cracks are initially difficult to detect, but if not detected and repaired in time, they will gradually develop into penetrating cracks, leading to problems such as groundwater seepage and steel corrosion. In severe cases, this can cause major safety accidents such as structural instability and collapse. Therefore, accurate detection of the depth of micro-cracks in underground large-volume concrete structures is a crucial step in ensuring the structural safety of engineering projects.

[0003] Currently, the industry mainly relies on ultrasonic testing technology to detect the depth of concrete cracks. The principle is to emit sound waves into the concrete using an ultrasonic probe and calculate the crack depth using the reflected signal characteristics at the crack interface. In existing technologies, the operation of ultrasonic testing instruments often relies on manual handheld operation, meaning the operator places at least two ultrasonic probes against the surface of the crack and obtains detection data by reading the sound wave propagation time difference or amplitude changes.

[0004] However, existing technologies have the following significant technical shortcomings when it comes to detecting minute cracks in large-volume underground concrete:

[0005] 1. Inconsistent contact force leads to decreased detection accuracy. Micro-cracks exhibit weak reflection signals and low identification accuracy, making them extremely sensitive to the contact state between the probe and the concrete surface. When manually holding the probe, individual differences in operator's force application habits and hand stability can easily lead to varying contact force between two or more probes and the surface, or even localized incomplete contact. This difference in force alters the propagation path and energy attenuation pattern of the ultrasonic waves, causing irregular deviations in the reflected signal. This makes it difficult to accurately distinguish between the true reflection from the crack and interference signals, ultimately resulting in a high error rate in crack depth detection results.

[0006] 2. Uneven coupling agent thickness exacerbates data dispersion. Ultrasonic testing requires applying coupling agent between the probe and the concrete surface to eliminate air gaps and ensure effective sound wave transmission. In existing technologies, the amount and distribution of coupling agent are entirely dependent on manual control. However, variations in the force applied by holding the probe can lead to uneven thickness of the coupling agent after compression (local thickness deviations can reach over 0.5 mm). For the detection of micro-cracks, even slight changes in coupling agent thickness can significantly affect the sound wave propagation speed, further amplifying the dispersion of the detection data and causing discrepancies in the results of multiple tests on the same crack.

[0007] 3. In the existing technology, the pressure of the probe on the surface depends entirely on the operator's experience and judgment. There is no clear pressure gradient standard or monitoring method. At the same time, when multiple probes are used for testing, it is impossible to verify whether each probe is under the same pressure state, which further increases the difficulty of data comparison.

[0008] In summary, existing ultrasonic testing technologies based on manual handheld operation suffer from technical bottlenecks in detecting the depth of micro-cracks in large-volume underground concrete, including unstable contact force, uneven distribution of couplant, and lack of quantitative pressure control. These limitations make it difficult to meet the engineering requirements for high-precision and high-reliability detection of micro-cracks. Therefore, developing an automated testing device capable of controlling clamping force, uniformly distributing couplant, and dynamically sensing and verifying the applied pressure is crucial to solving these technical problems. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a device for detecting micro-cracks in underground large-volume concrete that can overcome or at least partially solve the above problems.

[0010] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows: a device for detecting micro-cracks in large-volume underground concrete, comprising an I-beam frame composed of a main rod and a secondary rod, and further comprising: frames respectively set at both ends of the secondary rod, wherein a floating plate is set in the frame, and an ultrasonic probe is mounted on the floating plate; a positioning rod, one end of which is connected to the floating plate, and the other end extending away from the floating plate, wherein in its natural state, its end extends beyond the detection end face of the ultrasonic probe, so that the ultrasonic probe and the surface to be measured have an initial measurement distance; during measurement: a first force is applied, and the positioning rod is pre-retracted to the set stroke, so that the ultrasonic probe and the surface to be measured complete a one-stage force clamping of the ultrasonic probe; a second force is applied, so that the floating plate moves away from the bottom wall of the frame, and the completion of the two-stage force clamping of the ultrasonic probe is sensed by the positioning steel ball set on the floating plate; a third force is applied, so that the floating plate comes into contact with a pressure sensor two set on the top wall of the frame, and the cross-verification of the pressure sensor one and the pressure sensor two determines whether the force is up to standard. If the force is up to standard, a voice alarm is triggered, thus completing the three-stage force clamping of the ultrasonic probe.

[0011] Preferably, the auxiliary rod is slidably connected to the main rod via a connecting buckle, and a locking bolt is threaded onto the connecting buckle. The main rod and the auxiliary rod are respectively provided with scales.

[0012] Preferably, the pressure sensor one is installed on the auxiliary rod, and the pressure sensor one corresponds to the main rod. It collects pressure data in real time during the first, second and third stage of force pressing. The pressure sensor two on the top wall of the frame collects pressure data synchronously during the third stage of force pressing, so that the pressure sensor one and the pressure sensor two form a cross-verification mechanism.

[0013] Furthermore, a sealing cylinder is fixedly connected to the floating plate, and the end of the positioning rod with the piston slides in the sealing cylinder. A boss is provided on the inner wall of the sealing cylinder, and a spring is provided between the piston and the sealing cylinder. When the positioning rod is squeezed and retracted by the surface to be tested until the piston and the boss abut against each other and are limited, the ultrasonic probe is in contact with the surface to be tested, and a one-stage force clamping is completed.

[0014] Furthermore, a suction tube is provided on the sealing cylinder, which is connected to an external coupling fluid storage box. A drainage channel is provided in the positioning rod, one end of which is connected to the sealing cylinder and the other end passes through the outer periphery of the positioning rod and is connected to the drainage tube on the outer periphery of the positioning rod. The drainage tube leads to one side of the axis of the ultrasonic probe. A one-way valve is provided in both the suction tube and the drainage tube.

[0015] Preferably, guide posts are symmetrically fixedly connected to the floating plate, and the guide posts are slidably connected in the guide holes of the frame. A spring is sleeved on the guide post located between the floating plate and the top wall of the frame. An installation groove is opened on the outer periphery of the guide post, and the positioning steel ball is movably disposed in the installation groove. A spring is provided between the positioning steel ball and the installation groove. A groove is opened in the guide hole of the frame, and the groove corresponds to the positioning steel ball. An electromagnet is installed on the top surface of the floating plate, and the electromagnet corresponds to the sliding sleeve on the frame. When the electromagnet is energized, the floating plate and the sliding sleeve are attracted to each other.

[0016] Preferably, the frame is slidably mounted on the auxiliary rod via a sliding sleeve, and a locking bolt is threadedly connected to one side of the sliding sleeve to fix the frame to the auxiliary rod.

[0017] Furthermore, a second sealing cylinder is installed on the floating plate, and a piston rod is slidably connected in the second sealing cylinder. An air inlet pipe and an air outlet pipe are respectively connected to the second sealing cylinder. A one-way valve is provided on both the air inlet pipe and the air outlet pipe. The piston rod is fixedly connected to the positioning rod. The air outlet pipe leads to one side of the ultrasonic probe axis, and the air outlet end of the air outlet pipe is perpendicular to the liquid outlet end of the liquid outlet pipe.

[0018] Furthermore, when the pressure sensor reading of the one-stage force clamping exceeds the preset threshold range:

[0019] If the pressure sensor reading remains below the threshold of the one-stage force clamping and there is no obvious resistance feedback during the retraction of the positioning rod to the sealing cylinder and contact with the boss, it is determined that the spring 2 inside the sealing cylinder is broken, causing the positioning rod to be unable to provide sufficient support, causing the ultrasonic probe to contact the surface to be tested prematurely, the pressure not reaching the standard, triggering the abnormal voice alarm of the spring 2.

[0020] If the pressure sensor reading suddenly rises above the single-stage force clamping threshold and the positioning rod retracts haltingly, it is determined that the piston of the positioning rod is stuck against the inner wall of the sealing cylinder, requiring repair or replacement, triggering a positioning rod jamming voice alarm.

[0021] If the pressure sensor reading suddenly rises above the upper limit of the one-stage force clamping threshold, and there is no coupling agent being discharged from the drain pipe or the discharge volume is abnormal, it is determined that the drain pipe is blocked, triggering a voice alarm for drain pipe blockage.

[0022] Furthermore, when the three-stage force is applied, the pressure sensor on the top wall monitors the force value in real time. When the force value reaches the preset three-stage force threshold range, a primary compliance signal is triggered.

[0023] Simultaneously extract the real-time monitoring value of pressure sensor one on the auxiliary rod. If the value of pressure sensor one is within the three-stage force preset threshold range, and the ratio of the difference between the two detected values ​​to the value of pressure sensor two is ≤5%, then it is determined that the three-stage force pressing is accurate and meets the standard, triggering the final standard-meeting voice alarm signal.

[0024] If the pressure sensor reading exceeds the three-segment threshold range, or the difference between the two readings is greater than 5%, an abnormal force voice alarm signal will be triggered.

[0025] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0026] 1. This device for detecting micro-cracks in large-volume underground concrete achieves dual core benefits through the initial spacing design between the positioning rod and the ultrasonic probe. Firstly, the structure of the positioning rod end extending beyond the probe's detection surface ensures a safe distance between the probe and the surface being tested when not in use, effectively preventing damage from direct collisions during operation. Secondly, the positioning rod's ability to contact the surface before the ultrasonic probe allows for pre-positioning and confirmation of the ultrasonic probe's spacing and position via markers, avoiding waste of coupling agent and surface contamination caused by direct contact due to marker deviations. This provides a preliminary guarantee for the standardization of subsequent testing.

[0027] 2. This device for detecting micro-cracks in large-volume underground concrete exhibits significant advantages in its automatic supply of couplant driven by the retraction of the positioning rod during the one-stage pressing process. The coordinated design of the sealing cylinder one and the drain pipe enables precise discharge of couplant along the stroke of the positioning rod, replacing the crude method of traditional manual application and avoiding the problems of insufficient or excessive couplant. More importantly, the gas jet function of the sealing cylinder two, through vertically distributed air outlet pipes, evenly disperses the discharged couplant between the surfaces to be tested. Combined with the one-stage light pressure bonding, it ensures that the couplant fully fills the micro-gaps. This liquid-gas synergistic coupling optimization scheme creates a uniform medium environment for efficient sound wave propagation during subsequent force upgrades, effectively solving the signal attenuation problem caused by uneven thickness of manually applied couplant.

[0028] 3. This device for detecting micro-cracks in large-volume underground concrete utilizes a two-stage clamping mechanism that combines mechanical and elastic structures to create a precise force grading system. The positioning steel balls on the guide column and the grooves in the frame not only provide clear mechanical feedback to the operator through a "clicking sensation," ensuring stable application of the two-stage clamping force, but also transmit pressure through the elastic deformation of spring three, ensuring that the ultrasonic probe fits tightly against the concrete surface contour and eliminates air gaps. This design builds upon the basic fit of the first stage, further enhancing the wetting effect of the coupling agent, while providing transitional support for the three-stage stable pressure detection. Compared to the unquantitative control of traditional manual force application, this grading mechanism achieves a controllable progression of pressure from "light touch positioning" to "tight fit," avoiding probe displacement or coupling agent splashing caused by sudden changes in force.

[0029] 4. This device for detecting micro-cracks in large-volume underground concrete uses pressure sensor one to monitor the overall pressure in real time, and pressure sensor two to focus on the pressure of an ultrasonic probe on a single frame. Cross-verification between these two sensors ensures the accuracy of the three-stage pressure stabilization. This design builds upon the foundation of the two-stage pressure grading system, replacing manual experience-based judgment with quantified data, thus solving the signal fluctuation problem caused by pressure instability in traditional detection methods. Simultaneously, the symmetrical distribution of multiple frames and balanced pressure control keep the pressure deviation of the four ultrasonic probes within a small range, ensuring consistent ultrasonic propagation conditions and providing a reliable benchmark for comparative analysis of crack data at different locations.

[0030] 5. This device for detecting microcracks in large-volume underground concrete employs a segmented data acquisition mechanism. By recording crack depth data under different pressures in one, two, and three stages, it provides multi-dimensional references for microcrack analysis, solving the problem of insufficient data information under a single pressure. Meanwhile, a comprehensive anomaly alarm system undertakes pressure monitoring functions at each stage, accurately diagnosing faults such as spring breakage, positioning rod jamming, and coupling agent blockage. This allows for rapid identification of the problem's source, avoiding invalid detection or data errors. This combination of data layering and fault early warning not only improves the reliability of the detection results but also reduces equipment maintenance costs, ensuring the long-term stable operation of the device in complex underground environments.

[0031] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0032] In the attached diagram:

[0033] Figure 1 This is a three-dimensional structural schematic diagram of a device for detecting micro-cracks in large-volume underground concrete, as proposed in this invention.

[0034] Figure 2 This is a top view of a device for detecting micro-cracks in large-volume underground concrete, as proposed in this invention.

[0035] Figure 3 This is a schematic diagram of a pressure sensor for detecting micro-cracks in large-volume underground concrete, as proposed in this invention.

[0036] Figure 4 This is a schematic diagram of the frame, floating plate, and ultrasonic probe of a device for detecting micro-cracks in large-volume underground concrete, as proposed in this invention.

[0037] Figure 5 This is a schematic diagram of the sealing cylinder one, sealing cylinder two, and spring two of the device for detecting micro-cracks in underground large-volume concrete proposed in this invention;

[0038] Figure 6 This is a schematic diagram of the positioning steel ball and groove of the device for detecting micro-cracks in underground large-volume concrete proposed in this invention;

[0039] Figure 7 This is a diagram showing the initial distance between the positioning rod and the ultrasonic probe. Figure 1 ;

[0040] Figure 8 This is a diagram showing the initial distance between the positioning rod and the ultrasonic probe. Figure 2 ;

[0041] Figure 9The height position between the positioning rod and the ultrasonic probe when applying a single-stage clamping force. Figure 1 ;

[0042] Figure 10 The height position between the positioning rod and the ultrasonic probe when applying a single-stage clamping force. Figure 2 ;

[0043] Figure 11 Positioning of the floating plate and positioning steel balls when applying two-stage clamping force. Figure 1 ;

[0044] Figure 12 Positioning of the floating plate and positioning steel balls when applying two-stage clamping force. Figure 2 ;

[0045] Figure 13 Position of the floating plate relative to the top wall when applying three-stage pressure. Figure 1 ;

[0046] Figure 14 Position of the floating plate relative to the top wall when applying three-stage pressure. Figure 2 .

[0047] In the diagram: 1. I-beam frame; 11. Main rod; 12. Secondary rod; 13. Connecting buckle; 14. Locking bolt (one); 15. Handle; 16. Scale; 17. Pressure sensor (one);

[0048] 2. Frame; 21. Bottom wall; 22. Top wall; 23. Groove; 24. Sliding sleeve; 25. Locking bolts (two);

[0049] 3. Floating plate; 30. Top surface; 31. Guide post; 32. Spring three; 33. Mounting groove; 34. Spring one; 35. Positioning steel ball; 36. Groove; 37. Electromagnet;

[0050] 4. Ultrasonic probe; 41. Positioning rod; 42. Spring 2; 43. Sealing cylinder 1; 44. Boss; 45. Suction tube; 46. Drainage channel; 47. Drainage tube;

[0051] 5. Sealing cylinder two; 51. Piston rod; 52. Inlet pipe; 53. Outlet pipe;

[0052] 6. Pressure sensor two. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0054] The following is in conjunction with the appendix Figure 1- Appendix Figure 14 The technical solutions provided in the various embodiments of the present invention will be described in detail.

[0055] Example: Refer to Figures 1-14 A device for detecting micro-cracks in large-volume underground concrete is disclosed. The overall structure of the device is based on an I-beam frame 1 as the core supporting component. The I-beam frame 1 consists of a main rod 11 and multiple auxiliary rods 12. The number of auxiliary rods 12 can be increased or decreased according to the actual use scenario and the number of cracks. The main rod 11 and auxiliary rods 12 are made of high-strength aluminum alloy, which has high strength and light weight, making it easy to carry and operate. Protective sleeves are inserted at both ends of the main rod 11. The auxiliary rods 12 can be installed or removed by removing the protective sleeves. The auxiliary rod 12 is slidably connected to the main rod 11 via a connecting buckle 13. A locking bolt 14 is threaded onto the connecting buckle 13. Tightening the locking bolt 14 can fix the auxiliary rod 12 to any position on the main rod 11. The main rod 11 and the auxiliary rod 12 are each equipped with a scale 16, facilitating adjustment of the relative position between the two auxiliary rods 12 as needed. This allows for adjustment of the position and spacing of the ultrasonic probes 4 according to the different orientations required for the "same-side crack test method" (where two ultrasonic probes 4 in a set are placed on the same side of the crack) and the "double-sided crack test method" (where two ultrasonic probes 4 in a set are placed on opposite sides of the crack). This device, by setting two sets of ultrasonic probes 4 and rotating the angle between the I-beam frame 1 and the crack, facilitates both same-side and double-sided crack tests.

[0056] A frame 2 is provided at both ends of the auxiliary rod 12. The frame 2 is slidably mounted on the auxiliary rod 12 via a sliding sleeve 24. A locking bolt 25 is threadedly connected to one side of the sliding sleeve 24. Tightening the locking bolt 25 can fix the frame 2 on the auxiliary rod 12.

[0057] The frame 2 has a floating plate 3 inside, and the ultrasonic probe 4 is installed on the floating plate 3 (using a threaded connection to facilitate installation, disassembly and adjustment of the height difference between multiple ultrasonic probes 4). The ultrasonic probe 4 penetrates the bottom wall 21 of the frame 2 and is used to transmit and receive ultrasonic signals to detect the depth of concrete cracks.

[0058] A positioning rod 41 is connected to the floating plate 3. One end of the positioning rod 41 is connected to the floating plate 3, and the other end extends away from the floating plate 3 and passes through the bottom wall 21 of the frame 2. In its natural state, the end of the positioning rod 41 extends beyond the detection end face of the ultrasonic probe 4, thereby maintaining an initial test distance between the ultrasonic probe 4 and the surface to be tested. A sealing cylinder 43 is also fixedly connected to the floating plate 3. The piston-equipped end of the positioning rod 41 slides in the sealing cylinder 43. A boss 44 is provided on the inner wall of the sealing cylinder 43. A spring 42 connects the piston on the positioning rod 41 to the sealing cylinder 43.

[0059] A suction tube 45 is provided on the sealing cylinder 43, which is connected to the external coupling fluid storage box. A drainage channel 46 is provided in the positioning rod 41. One end of the drainage channel 46 is connected to the sealing cylinder 43, and the other end passes through the outer periphery of the positioning rod 41 and is connected to the drainage tube 47 on the outer periphery of the positioning rod 41. The drainage tube 47 leads to one side of the axis of the ultrasonic probe 4. Both the suction tube 45 and the drainage tube 47 are equipped with one-way valves to ensure that the coupling fluid can only flow in one direction.

[0060] Guide posts 31 are symmetrically fixedly connected to the floating plate 3. The guide posts 31 are slidably connected in the guide holes of the frame 2. A spring 32 is sleeved on the guide post 31 located between the floating plate 3 and the top wall 22 of the frame 2. An installation groove 33 is opened on the outer periphery of the guide post 31. A positioning steel ball 35 is movably disposed in the installation groove 33. A spring 34 is arranged between the positioning steel ball 35 and the installation groove 33. A groove 36 is opened in the guide hole of the frame 2, and the groove 36 corresponds to the positioning steel ball 35. An electromagnet 37 is installed on the top surface 30 of the floating plate 3. The electromagnet 37 corresponds to the sliding sleeve 24 on the frame 2. When the electromagnet 37 is energized, the floating plate 3 and the sliding sleeve 24 are attracted to each other.

[0061] A second sealing cylinder 5 is installed on the floating plate 3. A piston rod 51 is slidably connected in the second sealing cylinder 5 and is fixedly connected to the positioning rod 41. An air inlet pipe 52 and an air outlet pipe 53 are connected to the second sealing cylinder 5. Both the air inlet pipe 52 and the air outlet pipe 53 are equipped with one-way valves. The air outlet pipe 53 leads to one side of the axis of the ultrasonic probe 4, and the air outlet end of the air outlet pipe 53 is perpendicular to the liquid outlet end of the drain pipe 47. The top wall 22 of the frame 2 has a slot 23, which can be used to prevent the first sealing cylinder 43 and the second sealing cylinder 5 from moving upward when the floating plate 3 floats, and at the same time, it can facilitate the observation of the upward movement of the floating plate 3.

[0062] Reference Figure 3 A pressure sensor 17 is installed inside the secondary rod 12. One end of the pressure sensor 17 penetrates the upper surface of the secondary rod 12 and corresponds to the bottom surface of the main rod 11. (It should be understood that...) Figure 3 The pressure sensor 17 shown is visible through the auxiliary rod 12. The pressure sensor 17 is installed on the auxiliary rod 12, which is opposite to the main rod 11. The pressure sensor 26 is installed on the top wall 22 of the frame 2. The pressure sensor 26 corresponds to the top surface 30 of the floating plate 3. The pressure sensor 17 collects pressure data in real time during the first, second, and third stage of force pressing. The pressure sensor 26 on the top wall 22 of the frame 2 simultaneously collects pressure data from the floating plate 3 during the third stage of force pressing, so that the pressure sensor 17 and the pressure sensor 26 form a cross-verification mechanism.

[0063] Before conducting concrete crack depth detection, the operator first adjusts the position of the auxiliary rod 12 on the main rod 11 and the position of the frame 2 on the auxiliary rod 12 according to the location and extent of the concrete cracks to be detected, using the scale 16 on the main rod 11 and auxiliary rod 12. After adjustment, the locking bolts 14 and 25 are tightened to fix them in place. At the same time, ensure that there is enough coupling fluid in the external coupling fluid storage box, and replenish the coupling fluid into the sealing cylinder 43 through the suction pipe 45.

[0064] When testing crack depth:

[0065] When the operator applies force for the first time, the positioning rod 41 retracts to the set stroke (that is, the piston at one end of the positioning rod 41 reaches the boss 44 and abuts against the boss 44), so that the ultrasonic probe 4 contacts the surface to be tested, and contacts the surface to be tested with a one-stage force, and the crack depth data detected by the ultrasonic probe 4 under the one-stage force is recorded by the detector.

[0066] The initial test distance reserved between the positioning rod 41 and the ultrasonic probe 4 ensures that the ultrasonic probe 4 does not contact the test surface when the positioning rod 41 is in contact with the test surface, thus protecting the ultrasonic probe 4 before use. The positioning rod 41 is used to position the basic ultrasonic probe 4 (this positioning refers to determining the distance between two ultrasonic probes 4 in a set when detecting the depth of concrete cracks, and marking the contact position of the ultrasonic probe 4 on the test surface. Therefore, by first contacting the positioning rod 41 with the marked point, it is easy to confirm or readjust the position between the ultrasonic probes 4. If the marked position is incorrect, the ultrasonic probe 4 will directly contact the test surface, which will lead to waste of coupling agent and residual coupling agent on the test surface, affecting the test results). When a one-stage force is applied to tighten the pressure, the ultrasonic probe 4 on the I-beam 1 slowly contacts the test surface, thus protecting the ultrasonic probe 4. The designed one-stage force tightening operation method ensures that the ultrasonic probe 4 fits precisely with the test surface (without excessive pressure), avoiding the ultrasonic probe 4 from shifting due to excessive initial pressure, which would lead to inaccurate testing.

[0067] When the operator applies force for the second time, the electromagnet 37 is de-energized by operating the switch installed on the handle 15, and the floating plate 3 is no longer attracted to the frame 2. At this time, when force is applied for the second time, the floating plate 3 will move away from the bottom wall 21 of the frame 2 and compress the spring 32. (Because the positioning rod 41 has already abutted the protrusion 44 on the inner wall of the sealing cylinder 43 during the first application of force, the force is directly transmitted to the sealing cylinder 43 during the second application of force. And since the sealing cylinder 43 is installed on the floating plate 3, the force is directly transmitted to the sealing cylinder 43 during the second application of force.) When force is applied, the floating plate 3 will move, causing the positioning steel ball 35 on the guide post 31 to enter the groove 36. Before the guide post 31 enters the groove 36, it will contact the guide hole on the frame 2, causing the positioning steel ball 35 to retract into the mounting groove 33. When the groove 36 and the positioning steel ball 35 are aligned, the positioning steel ball 35 will enter the groove 36 under the push of the spring 34. This action process will have a "clunking" sensation transmitted to the operator's hand, thereby sensing the completion of the two-stage force clamping of the ultrasonic probe 4.

[0068] The two-stage pressure clamping, through the cooperation of positioning steel ball 35 and groove 36, achieves graded pressure enhancement, ensuring that ultrasonic probe 4 is in close contact with the surface to be tested, while providing clear operational feedback, allowing the operator to dynamically perceive the implementation of the two-stage pressure clamping. The preset threshold range of the two-stage pressure clamping is 40-50N, and pressure sensor 17 monitors and records the pressure data of this stage in real time. In contrast, the one-stage pressure clamping only achieves "contact between ultrasonic probe 4 and the surface to be tested". However, the concrete surface may have small protrusions, pores or surface cracks. Therefore, the two-stage pressure clamping appropriately increases the pressure to make ultrasonic probe 4 fit the contour of the surface to be tested more closely, and ensures that the coupling agent is evenly distributed on ultrasonic probe 4 and the surface to be tested. At the same time, the two-stage pressure clamping is transmitted through the elastic deformation of spring 32, and the force is greater than that of the one-stage clamping, which can further eliminate the air gap between ultrasonic probe 4 and the surface to be tested, and enhance the wetting effect of coupling agent.

[0069] After the two-stage force compression is applied, the data under this condition is recorded by a detector electrically connected to the ultrasonic probe 4.

[0070] The operator applies force for the third time, causing the floating plate 3 to come into contact with the pressure sensor 6 on the top wall 22 of the frame 2. The operator then cross-verifies the force between the pressure sensor 17 and the pressure sensor 6 to determine whether the force is sufficient. If the force is sufficient, an audio alarm is triggered to complete the three-stage force pressing of the ultrasonic probe 4.

[0071] Three-stage pressure is applied on the basis of the two-stage pressure. The positioning steel ball 35 on the guide post 31 disengages from the groove 36, and the floating plate 3 continues to move upward to overcome the spring 32 until it comes into contact with the pressure sensor 6 on the top wall 22 of the frame 2. At this time, the pressure sensor 6 monitors the pressure in real time, and the pressure sensor 17 on the auxiliary rod 12 collects the overall pressure data synchronously. When both values ​​are within the preset threshold range (the preset threshold range for three-stage pressure is 55-65N) and the difference is ≤5%, the pressure is determined to be up to standard, triggering a voice alarm, completing the final pressure, and the data in this state is recorded by the detector.

[0072] Therefore, by applying different pressure values ​​in one, two, and three stages, the ultrasonic probe 4 can measure the depth data of concrete cracks under different clamping forces, which facilitates in-depth analysis of the data under different forces and improves the accuracy of depth detection of micro-cracks.

[0073] During the initial force application, the positioning rod 41, with its piston-equipped end, slides within the sealing cylinder 43 during retraction, compressing the spring 42. As the positioning rod 41 retracts, the coupling fluid within the sealing cylinder 43 is squeezed and discharged through the drainage channel 46 and drainage pipe 47, spraying onto the area between the ultrasonic probe 4 and the surface to be tested. When the positioning rod 41 retracts to the point where the piston and boss 44 abut against each other, the ultrasonic probe 4 comes into contact with the surface to be tested, completing the one-stage force clamping. During this process, pressure sensor 17 collects pressure data in real time, and the preset threshold range for the one-stage force clamping is 10-20N. Therefore, this device, through the positioning rod 41, not only ensures a safe distance between the ultrasonic probe 4 and the surface to be tested in the initial state, but also automatically drives the spraying of the coupling agent while providing downward pressure damping, reducing the need for manual application of the coupling agent. Furthermore, the cooperation between the positioning rod 41 and the boss 44 provides dynamic sensing feedback for the one-stage force clamping operation.

[0074] At the same time, the retraction of the positioning rod 41 causes the piston rod 51 to slide inside the sealing cylinder 2 5. The gas inside the sealing cylinder 2 5 is compressed and discharged from the vent pipe 53. Since the vent end of the vent pipe 53 and the drain end of the drain pipe 47 are perpendicularly distributed, the sprayed gas can evenly disperse the discharged coupling liquid between the ultrasonic probe 4 and the surface to be tested, ensuring the coupling effect.

[0075] In some implementations, when the pressure sensor 17 of the one-stage force clamping exceeds the preset threshold range, the device will automatically determine the fault and trigger an alarm.

[0076] If the pressure sensor 17 detects a value that is consistently below the lower limit of the one-stage force clamping threshold, and there is no obvious resistance feedback during the retraction of the positioning rod 41 to the contact between the sealing cylinder 43 and the boss 44, it is determined that the spring 42 inside the sealing cylinder 43 is broken, causing the positioning rod 41 to be unable to provide sufficient support, causing the ultrasonic probe 4 to contact the surface to be tested prematurely, and the pressure does not reach the standard, triggering an abnormal voice alarm of the spring 42.

[0077] If the pressure sensor 17 detects a sudden increase in value exceeding the upper limit of the one-stage force clamping threshold, and the positioning rod 41 is stuck during the retraction process, it is determined that the piston of the positioning rod 41 is stuck with the inner wall of the sealing cylinder 43, and needs to be repaired or replaced, triggering a voice alarm for the stuck positioning rod 41.

[0078] If the pressure sensor 17 detects a sudden increase in value exceeding the upper limit of the one-stage force clamping threshold, and there is no coupling agent discharged from the drain pipe 47 or the discharge volume is abnormal, then the drain pipe 47 is determined to be blocked, triggering a voice alarm for the blockage of the drain pipe 47.

[0079] In some implementations, when the three-stage force is applied, the pressure sensor 26 on the top wall 22 monitors the force value in real time. When the force value reaches the preset three-stage force threshold range, a primary compliance signal is triggered.

[0080] Synchronously extract the real-time monitoring value of pressure sensor 17 on the auxiliary rod 12. If the value of pressure sensor 17 is within the three-stage force preset threshold range, and the ratio of the difference between the two detected values ​​to the value of pressure sensor 6 is ≤5%, then it is determined that the three-stage force pressing is accurate and meets the standard, triggering the final standard-meeting voice alarm signal.

[0081] If the pressure sensor reading exceeds the three-segment threshold range, or the difference between the two values ​​is greater than 5%, an abnormal force voice alarm signal will be triggered.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A device for detecting micro-cracks in large-volume underground concrete, comprising an I-beam frame (1) consisting of a main rod (11) and a secondary rod (12), characterized in that, Also includes: A frame (2) is set at both ends of the auxiliary rod (12), and a floating plate (3) is set in the frame (2). The ultrasonic probe (4) is installed on the floating plate (3). The positioning rod (41) is connected to the floating plate (3) at one end and extends away from the floating plate (3) at the other end. In its natural state, its end extends beyond the detection end face of the ultrasonic probe (4), so that the ultrasonic probe (4) and the surface to be measured have an initial test distance. During measurement: When applying force for the first time, the positioning rod (41) is retracted to the set stroke in advance, so that the ultrasonic probe (4) and the surface to be measured are pressed together in one step. The second force is applied to move the floating plate (3) away from the bottom wall (21) of the frame (2), and the positioning steel ball (35) set on the floating plate (3) senses the completion of the two-stage force pressing of the ultrasonic probe (4); The third force is applied to make the floating plate (3) come into contact with the pressure sensor 2 (6) set on the top wall (22) of the frame (2). The force is determined by cross-verification between pressure sensor 1 (17) and pressure sensor 2 (6). If the force is up to standard, a voice alarm is triggered to complete the three-stage force pressing of the ultrasonic probe (4). The auxiliary rod (12) is slidably connected to the main rod (11) via a connecting buckle (13). A locking bolt (14) is threaded onto the connecting buckle (13). Scales (16) are respectively provided on the main rod (11) and the auxiliary rod (12). The pressure sensor 1 (17) is installed on the auxiliary rod (12). The pressure sensor 1 (17) corresponds to the main rod (11) and collects pressure data in real time during the first, second and third stage force pressing process. The pressure sensor 2 (6) on the top wall (22) of the frame (2) collects pressure data synchronously during the three-stage force pressing, so that the pressure sensor 1 (17) and the pressure sensor 2 (6) form a cross-verification mechanism. The floating plate (3) is symmetrically fixed with guide posts (31), which are slidably connected in the guide holes of the frame (2). A spring (32) is sleeved on the guide post (31) located between the floating plate (3) and the top wall (22) of the frame (2). An installation groove (33) is opened on the outer periphery of the guide post (31). The positioning steel ball (35) is movably arranged in the installation groove (33). A spring (34) is arranged between the positioning steel ball (35) and the installation groove (33). A groove (36) is opened in the guide hole of the frame (2). The groove (36) corresponds to the positioning steel ball (35). An electromagnet (37) is installed on the top surface (30) of the floating plate (3). The electromagnet (37) corresponds to the sliding sleeve (24) on the frame (2). When the electromagnet (37) is energized, the floating plate (3) and the sliding sleeve (24) are attracted to each other.

2. The device for detecting micro-cracks in large-volume underground concrete according to claim 1, characterized in that, A sealing cylinder (43) is fixedly connected to the floating plate (3). The end of the positioning rod (41) with the piston slides in the sealing cylinder (43). A boss (44) is provided on the inner wall of the sealing cylinder (43). A spring (42) is provided between the piston and the sealing cylinder (43). When the positioning rod (41) is squeezed and retracted by the surface to be tested until the piston and the boss (44) come into contact and limit the movement, the ultrasonic probe (4) is in contact with the surface to be tested, and the one-stage force pressing is completed.

3. The device for detecting micro-cracks in large-volume underground concrete according to claim 2, characterized in that, A suction tube (45) is provided on the sealing cylinder (43). The suction tube (45) is connected to the external coupling liquid storage box. A drain channel (46) is provided in the positioning rod (41). One end of the drain channel (46) is connected to the sealing cylinder (43), and the other end passes through the outer periphery of the positioning rod (41) and is connected to the drain pipe (47) on the outer periphery of the positioning rod (41). The drain pipe (47) leads to one side of the axis of the ultrasonic probe (4). A one-way valve is provided in both the suction tube (45) and the drain pipe (47).

4. The device for detecting micro-cracks in large-volume underground concrete according to claim 1, characterized in that, The frame (2) is slidably mounted on the auxiliary rod (12) via a sliding sleeve (24). A locking bolt (25) is threadedly connected to one side of the sliding sleeve (24). The locking bolt (25) is used to fix the frame (2) on the auxiliary rod (12).

5. The device for detecting micro-cracks in large-volume underground concrete according to claim 3, characterized in that, A sealing cylinder 2 (5) is installed on the floating plate (3). A piston rod (51) is slidably connected in the sealing cylinder 2 (5). An air inlet pipe (52) and an air outlet pipe (53) are respectively connected to the sealing cylinder 2 (5). A one-way valve is provided on both the air inlet pipe (52) and the air outlet pipe (53). The piston rod (51) is fixedly connected to the positioning rod (41). The air outlet pipe (53) leads to one side of the axis of the ultrasonic probe (4), and the air outlet end of the air outlet pipe (53) is perpendicular to the liquid outlet end of the drain pipe (47).

6. The device for detecting micro-cracks in large-volume underground concrete according to claim 1, characterized in that, When the pressure sensor 1 (17) of the one-stage force clamping exceeds the preset threshold range: If the value detected by pressure sensor 1 (17) is consistently lower than the threshold of the one-stage force pressing, and there is no obvious resistance feedback during the process of the positioning rod (41) retracting to the sealing cylinder 1 (43) and the boss (44), it is determined that the spring 2 (42) inside the sealing cylinder 1 (43) is broken, causing the positioning rod (41) to be unable to provide sufficient support, causing the ultrasonic probe (4) to contact the surface to be tested prematurely, and the pressure does not reach the standard, triggering the abnormal voice alarm of spring 2 (42); If the value detected by pressure sensor 1 (17) suddenly rises above the upper limit of the one-stage force clamping threshold, and the positioning rod (41) is stuck during the retraction process, it is determined that the piston of the positioning rod (41) is stuck with the inner wall of the sealing cylinder 1 (43), and needs to be repaired or replaced, triggering the positioning rod (41) stuck voice alarm. If the value detected by pressure sensor 1 (17) suddenly rises above the upper limit of the one-stage force clamping threshold, and there is no coupling agent discharged from the drain pipe (47) or the discharge volume is abnormal, it is determined that the drain pipe (47) is blocked, triggering a voice alarm for the blockage of the drain pipe (47).

7. The device for detecting micro-cracks in large-volume underground concrete according to claim 6, characterized in that, When the three-stage force is applied, the pressure sensor 2 (6) on the top wall (22) monitors the force value in real time. When the force value reaches the preset three-stage force threshold range, the primary compliance signal is triggered. Synchronously extract the real-time monitoring value of pressure sensor 1 (17) on the auxiliary rod (12). If the value of pressure sensor 1 (17) is within the three-stage force preset threshold range, and the ratio of the difference between the two detected values ​​to the value of pressure sensor 2 (6) is ≤5%, then it is determined that the three-stage force pressing is accurate and the final standard voice alarm signal is triggered. If the value of pressure sensor 1 (17) exceeds the three-segment threshold range, or the difference between the two values ​​is greater than 5%, an abnormal force voice alarm signal will be triggered.

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