Hydraulic engineering crack expansion joint change detection device and method thereof

Abstract

The invention belongs to the technical field of hydraulic engineering expansion joint detection, and discloses a hydraulic engineering crack expansion joint change detection device and a method thereof.The device comprises a walking frame, and a square opening beam and a double-pipe armrest frame are fixed to the front outer wall and the rear outer wall of the walking frame correspondingly; an outer square opening stand column is detachably installed on the outer wall of the side, close to the double-pipe armrest frame, of the square opening beam, an inner square opening column is slidably installed in the outer square opening stand column in the vertical direction, the lower end of the inner square opening column extends to the exterior of the outer square opening stand column and is provided with an elastic self-returning type indication structure, and a graduated scale is fixed to the outer wall of one side of the outer square opening stand column. A lead screw lifting structure used for controlling the height position of the inner square opening column and the height position of the elastic self-returning type indication structure is arranged in the outer square opening column, a power source control box is installed on the outer wall of one side of the double-pipe armrest frame, and a monitoring assembly is installed on the portion, below the power source control box, of the walking frame. And the accuracy of detection data is improved.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic engineering expansion joint detection technology, specifically, it relates to a device and method for detecting changes in hydraulic engineering crack expansion joints. Background Technology

[0002] Expansion joints in concrete roads of large-scale water conservancy projects are crucial structures designed to accommodate the expansion and contraction of the structure due to changes in temperature and humidity. Whether their depth meets design requirements directly affects the safety and durability of the road. The main function of a crack expansion joint measuring device is to accurately detect the actual depth of the expansion joint, ensuring it meets design standards and preventing structural cracking due to insufficient depth. Such devices typically consist of a measuring probe, a guide device, a reading device, and a support structure. The measuring probe is slender and robust, capable of penetrating deep into the crack. The guide device ensures vertical insertion of the probe, the reading device displays the measurement results, and the support structure facilitates operation. During use, the device should be placed stably at the measurement point, ensuring good contact between the reference surface and the road surface. Then, the probe is slowly lowered until it lightly touches the bottom of the crack, and the depth value is obtained through mechanical reading or digital display. Finally, multiple measurements are taken on the same cross-section, and the average value is calculated to reduce errors. The location of the measuring point and the results are recorded in detail.

[0003] Chinese invention patent application number CN202110662582.X discloses a device for detecting changes in expansion joints and cracks in large-scale water conservancy projects. The device includes a frame, two depth measuring mechanisms, a width measuring mechanism, and a reading mechanism. The two depth measuring mechanisms are symmetrically arranged on both sides of the top of the frame, corresponding to the crack positions on the frame. The width measuring mechanism is installed on one of the depth measuring mechanisms, and the reading mechanism is installed on the other. Each depth measuring mechanism includes a mounting assembly and a depth measuring component. In embodiment 5, a pressure sensor processes data through a data processor and transmits it to a display terminal via a data transmission module. A camera transmits the collected data to the display terminal via a data acquisition module. The pressure sensor detects the depth of the cracks in the frame in real time. As the crack depth changes, the pressure on the sliding plate varies, allowing the data to be displayed in real time on the terminal screen under the coordination of the data processor. The camera collects data from the measuring ruler in real time and transmits it to the terminal display.

[0004] It can be seen that the above technical solution mainly adopts a fixed-point measurement method. In continuous measurement operations, workers need to continuously move and adjust the position of the device along the extension direction of the expansion joint of the concrete road. That is, to reach the predetermined position, put down the device, clean the gap at the measuring point, place the device stably, level it, lower the probe, record the reading, and then pack up the equipment and walk to the next measuring point to start the cycle again. In essence, it is a sampling inspection method. Its results depend heavily on the selection of measuring points. However, the depth of the expansion joint may be uneven in reality. The depth may be qualified at some points, but in the unmeasured area between two measuring points, there may be sudden changes in depth or shallow points due to uneven cutting, base settlement, or local damage. Therefore, the point-to-line method is prone to missing some representative defect locations, thus failing to fully and accurately grasp the complete structural condition of the expansion joint. Summary of the Invention

[0005] The purpose of this invention is to provide a device and method for detecting changes in expansion joints in hydraulic engineering cracks. The frame moves along the extension direction of the expansion joint in a concrete road of a hydraulic engineering project via rubber wheels. During the movement, the operator pre-adjusts the initial position of the elastic self-returning indicator structure using a screw lifting structure, so that the lower end of the elastic self-returning indicator structure lightly touches the bottom of the expansion joint. As the device moves along the extension direction of the expansion joint, the elastic self-returning indicator structure indicates the corresponding position on a scale according to the change in the depth of the expansion joint. The monitoring component records the numerical changes on the scale during the movement, thereby reflecting the overall depth change of the expansion joint at that location, thus solving the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A device for detecting changes in expansion joints and cracks in hydraulic engineering includes a walking frame. A square beam and a double-tube handrail are welded and fixed to the front and rear outer walls of the walking frame, respectively. An outer square column is detachably installed on the outer wall of the square beam near the double-tube handrail. An inner square column is slidably installed vertically inside the outer square column. The lower end of the inner square column extends to the outside of the outer square column and is equipped with a flexible self-returning indicating structure. A scale is fixed on one outer wall of the outer square column. A screw-driven lifting structure for controlling the height of the inner square column and the flexible self-returning indicating structure is installed inside the outer square column. A power control box is installed on one outer wall of the double-tube handrail. A monitoring component is installed on the walking frame below the power control box. A touch screen is installed on one outer wall of the power control box. The power control box is communicatively connected to both the touch screen and the monitoring component. Information monitored by the monitoring component is synchronously displayed on the touch screen.

[0007] The following are further optimizations of the above technical solution by the present invention: Two rubber wheels are mounted on the left and right sides of the bottom of the walking frame via U-shaped wheel frames.

[0008] Further optimization: The monitoring component includes side seats fixedly installed on the left and right inner walls of the walking frame. Support plates are hinged between the inner walls of the two side seats on opposite sides. A CCD camera is installed on the support plate, and the lens of the CCD camera is facing the scale.

[0009] Further optimization: A locator is installed on the outer wall of the outer square-mouth column away from the double-tube handrail frame, and the outer square-mouth column is detachably connected to the square-mouth beam through the locator.

[0010] Further optimization: The positioner consists of a C-shaped seat, a hollow sleeve, and bolts. There are two C-shaped seats, which are respectively snapped onto the front and rear outer walls of the square beam. The hollow sleeve is integrally connected to the top and bottom of the C-shaped seat. The bolts are used to connect the two hollow sleeves at the same height. The C-shaped seat near the outer square beam is fixedly connected to the outer square beam.

[0011] Further optimization: The lead screw lifting structure includes a threaded rod that is vertically rotated and installed at the center of the top of the outer square column via a bearing. A nut pair is fixedly installed at the center of the top of the inner square column. The nut pair is threadedly engaged with the threaded rod. A handle is fixedly installed at the top of the threaded rod.

[0012] Further optimization: The square beam, outer square column, and inner square column are all made of stainless steel.

[0013] Further optimization: The elastic self-returning indicator structure includes a boss integrally connected to the outer wall of one side of the inner square column. A steel rod is slidably installed in the vertical direction inside the boss. An elastic reset structure is provided at the top of the boss. A label plate is fixed at the upper end of the steel rod, and a ball is embedded at the lower end of the steel rod. The elastic reset structure is used to force the steel rod, label plate, and ball to move down as a whole.

[0014] Further optimization: The elastic reset structure includes a cylindrical shell fixedly installed on the top of the boss, a helical spring installed on the inner top of the cylindrical shell, the helical spring and the steel rod being concentrically fitted together, and a baffle plate integrally formed on the outer surface of the steel rod, the upper surface of the baffle plate being fixedly connected to the lower end of the helical spring.

[0015] This invention also provides a method for detecting changes in expansion joints of cracks in hydraulic engineering projects, using the aforementioned device for detecting changes in expansion joints of cracks in hydraulic engineering projects, comprising the following steps: S101: The staff moves the device smoothly to the beginning of the expansion joint using the double-tube handrail, allowing the device to move smoothly along the direction of the gap. Then, the staff manually operates the screw lifting structure, which drives the inner square column and the elastic self-returning indicator structure to move down until the lower end of the elastic self-returning indicator structure is pressed against the bottom of the expansion joint. This position is set as the depth reference zero point. S102: The device is pushed forward along the direction of the expansion joint at a uniform, slow and continuous speed. Any micro-change in the depth of the expansion joint will be immediately transmitted to the elastic self-returning indicator structure in close contact with it. The elastic self-returning indicator structure will then generate a corresponding vertical displacement and move back and forth on the clearly marked scale to intuitively display the instantaneous value of the depth. At the same time, the monitoring component continuously captures and records every position change of the elastic self-returning indicator structure on the scale. The monitoring component synchronously displays the depth position information on the touch screen to form a visible depth change curve. S103: After the device is pushed to the preset detection endpoint, the operator operates on the touch screen to stop data recording, operates the screw lifting structure to fully raise the elastic self-returning indicator structure to a safe height and remove it from the expansion joint.

[0016] The present invention, by adopting the above technical solution, has at least the following beneficial effects: 1. The device in this invention can move along the extension direction of the expansion joint of the concrete road in the hydraulic engineering project. During the movement, the staff adjusts the initial position of the elastic self-returning indicator structure in advance through the screw lifting structure, so that the lower end of the elastic self-returning indicator structure lightly touches the bottom of the expansion joint. When the device moves along the extension direction of the expansion joint, the elastic self-returning indicator structure indicates the corresponding position on the scale according to the change of the expansion joint depth. The monitoring component records the change of the value on the scale during the movement, thereby reflecting the overall depth change of the expansion joint. This ensures that any tiny depth change, shallow point or continuous uneven settlement in the expansion joint is recorded without interruption, so as to truly reflect the complete depth view of the entire expansion joint's longitudinal contour, avoiding the risk of missing local defects that may occur with traditional fixed-point sampling.

[0017] 2. The invention automates and standardizes the measurement process by using a flexible self-returning indicator structure and a monitoring component for continuous monitoring and recording. Once the initial contact pressure is preset by the lead screw lifting structure before movement, the flexible self-returning indicator structure adaptively tracks the undulations of the seam bottom during the entire movement process, and the monitoring component objectively records all changes, eliminating operational deviations that vary from person to person and from time to time, making the data more objective and comparable. At the same time, the staff no longer need to repeatedly perform the actions of bending over, placing, reading, standing up, and carrying, greatly reducing the labor intensity. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of an embodiment of the present invention. Figure 1 ; Figure 2 This is a three-dimensional structural diagram of an embodiment of the present invention. Figure 2 ; Figure 3This is a front view of the overall structure of an embodiment of the present invention; Figure 4 This is a three-dimensional sectional view of the overall structure in an embodiment of the present invention; Figure 5 This is a three-dimensional structural diagram of an embodiment of the present invention. Figure 3 ; Figure 6 This is a schematic diagram of the locator in an embodiment of the present invention; Figure 7 This is a side sectional view of the overall structure in an embodiment of the present invention; Figure 8 for Figure 4 A magnified view of a section at point A in the middle; Figure 9 This is a three-dimensional structural diagram of an embodiment of the present invention. Figure 4 .

[0019] In the diagram: 1-Traveling frame; 101-Rubber wheel; 2-Square beam; 3-Double tube handrail; 4-Power control box; 5-Touch screen; 6-Monitoring components; 601-Side seat; 602-Support plate; 603-CCD camera; 7-Positioner; 701-C-shaped seat; 702-Hollow sleeve; 703-Bolt; 8-Outer square column; 9-Inner square column; 10-Screw lifting structure; 1001-Threaded rod; 1002-Nut pair; 1003-Handle; 11-Scale; 12-Elastic self-returning indicator structure; 1201-Boss; 1202-Cylinder shell; 1203-Helical spring; 1204-Steel rod; 1205-Baffle; 1206-Ball bearing; 1207-Marker plate. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] Depend on Figures 1 to 4As shown, a device for detecting changes in expansion joints and cracks in hydraulic engineering includes a walking frame 1. A square beam 2 and a double-tube handrail 3 are welded and fixed to the front and rear outer walls of the walking frame 1, respectively. An outer square column 8 is detachably installed on the outer wall of the square beam 2 near the double-tube handrail 3. An inner square column 9 is slidably installed in the vertical direction inside the outer square column 8. The lower end of the inner square column 9 extends to the outside of the outer square column 8 and is equipped with an elastic self-returning indicator structure 12. A scale 11 is fixed on one outer wall of the outer square column 8. A screw lifting structure 10 for controlling the height position of the inner square column 9 and the elastic self-returning indicator structure 12 is provided inside the outer square column 8. A power control box 4 is installed on one outer wall of the double-tube handrail 3. A monitoring component 6 is installed on the walking frame 1 below the power control box 4. The monitoring end of the monitoring component 6 faces the scale 11.

[0022] A touch screen 5 is installed on one outer wall of the power control box 4. The power control box 4 is communicatively connected to the touch screen 5 and the monitoring component 6. The information monitored by the monitoring component 6 is synchronously displayed on the touch screen 5.

[0023] In this embodiment, in order to convert the images captured by the monitoring component 6 into depth values ​​displayed on the touch screen 5, the power control box 4 needs to be equipped with a central processing module, an image acquisition and processing module, a data conversion and calibration module, a power management module, and a communication interface module. The central processing module schedules the entire data processing flow. The image acquisition module first receives the raw video stream from the monitoring component 6 and executes noise reduction and feature recognition algorithms to accurately lock the pixel coordinates of the pointer on the scale in each frame of the image. Then, the data conversion module calls the pre-calibrated millimeter-per-pixel ratio coefficient to convert the identified pixel displacement into the real physical depth value in real time. During this process, the power management module provides multi-channel regulated power supply to all electronic components to ensure their stable operation. The communication interface module is responsible for high-speed data transmission between all modules and sends the finally generated depth data and graphical interface to the touch screen 5 for real-time rendering and display.

[0024] Two rubber wheels 101 are rotatably mounted on the left and right sides of the bottom of the walking frame 1 via a U-shaped wheel frame. The U-shaped wheel frame is fixedly connected to the walking frame 1, and the rubber wheels 101 are rotatably connected to the U-shaped wheel frame.

[0025] The walking frame 1 serves as the core load-bearing structure, integrating all the dispersed components into a robust and unified whole, effectively resisting the torque and vibration generated during the pushing process. The elastic material of the rubber wheel 101 provides excellent shock absorption, smoothly absorbing the bumps caused by minor unevenness in the road surface, ensuring a stable working environment for the monitoring components.

[0026] Depend on Figure 5 and Figure 6As shown, the monitoring component 6 includes side seats 601 fixedly installed on the left and right inner walls of the walking frame 1. A support plate 602 is hinged between the inner walls of the two side seats 601 on opposite sides. A CCD camera 603 is installed on the support plate 602, and the lens of the CCD camera 603 faces the scale 11.

[0027] When using the monitoring component 6, the staff can initially adjust the working angle of the CCD camera 603 according to the position indicated on the scale 11 at the upper end of the elastic self-returning indicator structure 12. At this time, the support plate 602 deflects with the hinge axis as the central axis and the side seat 601. The CCD camera 603 monitors the position change of the elastic self-returning indicator structure 12 on the scale 11 in real time, converts the dynamic change of the expansion joint depth into a digital signal and transmits it to the power control box 4 and the touch display screen 5.

[0028] A locator 7 is installed on the outer wall of the outer square column 8 away from the double-tube handrail 3. The outer square column 8 is detachably connected to the square beam 2 through the locator 7.

[0029] The positioner 7 consists of a C-shaped seat 701, a hollow sleeve 702, and a bolt 703. There are two C-shaped seats 701, which are respectively snapped onto the front and rear outer walls of the square beam 2. The hollow sleeve 702 is integrally connected to the top and bottom of the C-shaped seat 701. The bolt 703 is used to connect the two hollow sleeves 702 at the same height position.

[0030] In this embodiment, the C-shaped base 701 near the outer square-mouth column 8 is fixedly connected to the outer square-mouth column 8.

[0031] When the device is not in operation, the operator can remove the bolt 703 from between the two hollow sleeves 702 to release the connection restriction between the two C-shaped seats 701. At this time, the outer square-mouth column 8, the inner square-mouth column 9, and the screw lifting structure 10 can be removed from the square-mouth beam 2 for easy assembly and installation.

[0032] Depend on Figure 7 , Figure 8 and Figure 9 As shown, the screw lifting structure 10 includes a threaded rod 1001 that is vertically rotatably mounted at the top center of the outer square column 8 via a bearing. A nut pair 1002 is fixedly mounted at the top center of the inner square column 9. The nut pair 1002 is threadedly engaged with the threaded rod 1001. The top end of the threaded rod 1001 extends above the outer square column 8 and is fixedly mounted with a handle 1003.

[0033] In this embodiment, the square beam 2, the outer square column 8, and the inner square column 9 are all made of stainless steel.

[0034] With this design, the operator rotates the threaded rod 1001 by holding the handle 1003. During the rotation of the threaded rod 1001, the threaded rod 1001 will drive the inner square post 9 and the elastic self-returning indicator structure 12 to move up and down through the nut pair 1002, so as to change the initial height of the elastic self-returning indicator structure 12 and thus set the initial position of the lower end of the elastic self-returning indicator structure 12 in contact with the bottom of the seam.

[0035] The elastic self-returning indicator structure 12 includes a boss 1201 integrally connected to the outer wall of one side of the inner square column 9. A steel rod 1204 is slidably installed in the vertical direction inside the boss 1201. An elastic reset structure is provided at the top of the boss 1201. A label plate 1207 is fixed at the upper end of the steel rod 1204. A ball bearing 1206 is embedded at the lower end of the steel rod 1204. The elastic reset structure is used to force the steel rod 1204, the label plate 1207, and the ball bearing 1206 to move downward as a whole.

[0036] The elastic reset structure includes a cylindrical shell 1202 fixedly installed on the top of the boss 1201. A helical spring 1203 is installed on the inner top of the cylindrical shell 1202. The helical spring 1203 and the steel rod 1204 are concentrically fitted together. A baffle 1205 is integrally formed on the outer surface of the steel rod 1204 below the helical spring 1203. The upper surface of the baffle 1205 is fixedly connected to the lower end of the helical spring 1203.

[0037] The output force of the helical spring 1203 pushes the baffle 1205, causing the steel rod 1204 to move downward. In the initial state, the helical spring 1203 fully releases its force, at which time the steel rod 1204 drives the ball 1206 to the bottom.

[0038] With this design, the lead screw lifting structure 10 adjusts the initial position of the elastic self-returning indicator structure 12, so that the ball 1206 contacts the bottom of the expansion joint. During the movement of the device, if the ball 1206 encounters a protrusion at the bottom of the joint, the ball 1206, the steel rod 1204, and the marker plate 1207 are pushed upward. The steel rod 1204 compresses the helical spring 1203 inside the cylinder shell 1202 through the baffle 1205. At this time, the marker plate 1207 moves to the corresponding position in front of the scale 11.

[0039] After the ball bearing 1206 moves past the protrusion at the bottom of the seam, the ball bearing 1206, the steel rod 1204, and the marker plate 1207 automatically reset themselves under their own weight and the elastic force of the coil spring 1203 and remain in contact with the bottom of the seam.

[0040] When the depth of the expansion joint changes, the elastic self-returning indicator structure 12 will exert an upward or downward force on the ball bearing 1206 based on the bottom contour of the joint. With the elastic deformation of the helical spring 1203, it closely follows every undulation of the bottom of the joint and transmits this linear displacement without delay, thereby achieving continuous tracking of the bottom contour of the joint and making it convenient to use.

[0041] This invention also provides a method for detecting changes in expansion joints of cracks in hydraulic engineering projects, using the aforementioned device for detecting changes in expansion joints of cracks in hydraulic engineering projects, comprising the following steps: S101: The staff uses the double-tube handrail 3 to smoothly move the device to the beginning of the expansion joint, so that the device can move smoothly along the extension direction of the gap. Then, the staff manually operates the screw lifting structure 10, which drives the inner square column 9 and the elastic self-returning indicator structure 12 to move down until the lower end of the elastic self-returning indicator structure 12 is pressed against the bottom of the expansion joint. This position is set as the depth reference zero point.

[0042] In step S101: When using and debugging the device, first select a representative expansion joint as the detection starting point, and use special cleaning tools, such as high-pressure blowers and steel hooks, to thoroughly remove the mud, gravel, and aged and failed sealant residue accumulated in the joint. At the same time as cleaning, perform a pre-power-on check of the device to confirm that the power control box 4 has sufficient power, and quickly connect the circuits of each component to ensure that the touch screen 5 and monitoring components 6 are in standby mode.

[0043] In step S101, the working principle of the screw lifting structure 10 is as follows: the operator rotates the screw rod 1001 by the handle 1003. During the rotation of the screw rod 1001, the screw rod 1001 will drive the inner square column 9 and the elastic self-returning indicator structure 12 to move up and down through the nut pair 1002, so that the lower end of the elastic self-returning indicator structure 12 contacts the bottom of the seam, and adjusts the contact pressure between the lower end of the elastic self-returning indicator structure 12 and the bottom of the seam.

[0044] S102: The device is pushed forward along the direction of the expansion joint at a uniform, slow and continuous speed. Any microscopic change in the depth of the expansion joint will be immediately transmitted to the elastic self-returning indicator structure 12 in close contact with it. The elastic self-returning indicator structure 12 will then generate a corresponding vertical displacement and move back and forth on the clearly marked scale 11, intuitively displaying the instantaneous value of the depth. At the same time, the monitoring component 6 continuously captures and records every position change of the elastic self-returning indicator structure 12 on the scale 11. The monitoring component 6 synchronously displays the depth position information on the touch screen 5, forming a visible depth change curve.

[0045] In step S102, the working principle of the elastic self-returning indicator structure 12 is as follows: the output force of the helical spring 1203 pushes the baffle 1205, causing the steel rod 1204 to move downward, so that the steel rod 1204 drives the ball 1206 to keep in close contact with the bottom of the expansion joint. When the steel rod 1204 and the ball 1206 move along the direction of the expansion joint, the change in the depth of the expansion joint will generate an upward or downward force on the ball 1206. At this time, the steel rod 1204 drives the scale plate 1207 to move up and down in front of the scale 11, thereby realizing the elastic deformation of the helical spring 1203 to closely follow every undulation of the bottom of the joint and transmit this linear displacement without delay, realizing continuous tracking of the bottom contour of the joint, which is convenient to use.

[0046] S103: After the device is pushed to the preset detection endpoint, the operator operates on the touch screen 5 to stop data recording, operates the screw lifting structure 10, and fully raises the elastic self-returning indicator structure 12 to a safe height to disengage from the expansion joint.

[0047] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for detecting changes in cracks and expansion joints in hydraulic engineering, characterized in that: The frame includes a walking frame (1). A square beam (2) and a double-tube handrail frame (3) are welded and fixed to the front and rear outer walls of the walking frame (1), respectively. An outer square column (8) is detachably installed on the outer wall of the square beam (2) near the double-tube handrail frame (3). An inner square column (9) is slidably installed inside the outer square column (8) in the vertical direction. The lower end of the inner square column (9) extends to the outside of the outer square column (8) and is equipped with an elastic self-returning indicator structure (12). A scale (11) is fixed on one side of the outer wall of the outer square column (8). The part is equipped with a screw lifting structure (10) for controlling the height position of the inner square column (9) and the elastic self-returning indicator structure (12). A power control box (4) is installed on one side of the outer wall of the double tube handrail (3). A monitoring component (6) is installed on the walking frame (1) below the power control box (4). A touch screen (5) is installed on one side of the outer wall of the power control box (4). The power control box (4) is connected to the touch screen (5) and the monitoring component (6) respectively. The information monitored by the monitoring component (6) is displayed synchronously on the touch screen (5).

2. The device for detecting changes in cracks and expansion joints in hydraulic engineering according to claim 1, characterized in that: The walking frame (1) has two rubber wheels (101) mounted on the left and right sides of its bottom end via a U-shaped wheel frame.

3. The device for detecting changes in cracks and expansion joints in hydraulic engineering according to claim 1, characterized in that: The monitoring component (6) includes side seats (601) fixedly installed on the left and right inner walls of the walking frame (1). A support plate (602) is hinged between the inner walls of the two side seats (601) on opposite sides. A CCD camera (603) is installed on the support plate (602), and the lens of the CCD camera (603) faces the scale (11).

4. The device for detecting changes in cracks and expansion joints in hydraulic engineering according to claim 1, characterized in that: A locator (7) is installed on the outer wall of the outer square column (8) away from the double-tube handrail frame (3), and the outer square column (8) is detachably connected to the square beam (2) through the locator (7).

5. The device for detecting changes in cracks and expansion joints in hydraulic engineering according to claim 4, characterized in that: The locator (7) consists of a C-shaped seat (701), a hollow sleeve (702), and a bolt (703). There are two C-shaped seats (701), which are respectively snapped onto the front and rear outer walls of the square beam (2). The hollow sleeve (702) is integrally connected to the top and bottom of the C-shaped seat (701). The bolt (703) is used to connect the two hollow sleeves (702) at the same height position. The C-shaped seat (701) near the outer square column (8) is fixedly connected to the outer square column (8).

6. The device for detecting changes in cracks and expansion joints in hydraulic engineering according to claim 1, characterized in that: The screw lifting structure (10) includes a threaded rod (1001) that is vertically rotated by a bearing and installed at the center of the top of the outer square column (8). A nut pair (1002) is fixedly installed at the center of the top of the inner square column (9). The nut pair (1002) is threadedly engaged with the threaded rod (1001). A handle (1003) is fixedly installed at the top of the threaded rod (1001).

7. The device for detecting changes in cracks and expansion joints in hydraulic engineering according to claim 1, characterized in that: The square beam (2), outer square column (8), and inner square column (9) are all made of stainless steel.

8. The device for detecting changes in cracks and expansion joints in hydraulic engineering according to claim 6, characterized in that: The elastic self-returning indicator structure (12) includes a boss (1201) integrally connected to the outer wall of one side of the inner square column (9). A steel rod (1204) is slidably installed inside the boss (1201) in the vertical direction. An elastic reset structure is provided at the top of the boss (1201). A label plate (1207) is fixed at the upper end of the steel rod (1204). A ball bearing (1206) is embedded at the lower end of the steel rod (1204). The elastic reset structure is used to force the steel rod (1204), label plate (1207), and ball bearing (1206) to move down as a whole.

9. The device for detecting changes in cracks and expansion joints in hydraulic engineering according to claim 8, characterized in that: The elastic reset structure includes a cylindrical shell (1202) fixedly installed on the top of the boss (1201). A helical spring (1203) is installed on the inner top of the cylindrical shell (1202). The helical spring (1203) and the steel rod (1204) are concentrically fitted together. A baffle (1205) is integrally formed on the outer surface of the steel rod (1204). The upper surface of the baffle (1205) is fixedly connected to the lower end of the helical spring (1203).

10. A method for detecting changes in expansion joints of cracks in hydraulic engineering projects, using the hydraulic engineering expansion joint change detection device as described in any one of claims 1-9, characterized in that: Includes the following steps: S101: The staff moves the device smoothly to the beginning of the expansion joint using the double-tube handrail (3), so that the device moves smoothly along the extension direction of the gap. Then, the staff manually operates the screw lifting structure (10), which drives the inner square column (9) and the elastic self-returning indicator structure (12) to move down until the lower end of the elastic self-returning indicator structure (12) is pressed against the bottom of the expansion joint. This position is set as the depth reference zero point. S102: The device is pushed forward along the direction of the expansion joint at a uniform, slow and continuous speed. Any micro-change in the depth of the expansion joint will be immediately transmitted to the elastic self-returning indicator structure (12) in close contact with it. The elastic self-returning indicator structure (12) will then generate a corresponding vertical displacement and move back and forth on the clearly marked scale (11) to intuitively display the instantaneous value of the depth. At the same time, the monitoring component (6) continuously captures and records every position change of the elastic self-returning indicator structure (12) on the scale (11) throughout the process. The monitoring component (6) synchronously displays the depth position information on the touch screen (5) to form a visible depth change curve. S103: After the device is pushed to the preset detection endpoint, the staff operates on the touch screen (5) to stop data recording, operates the screw lifting structure (10) to fully lift the elastic self-returning indicator structure (12) to a safe height and get out of the expansion joint.

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