Radar device for detecting diseases behind shield tunnel wall

Abstract

The invention relates to the technical field of tunnel wall back disease detection, in particular to a radar device for shield tunnel wall back disease detection, which comprises a base, a movable bracket, a track structure and a radar detection mechanism, and is characterized in that the track structure and any section of a tunnel are kept in a concentric state by adjusting the horizontal position of the movable bracket on the base; an arc-shaped groove is formed in the inner side face of the arc-shaped guide rail, an inclined face facing the outer side of the track structure is arranged on the upper surface of the arc-shaped guide rail, the radar detection mechanism comprises a moving trolley and a ground penetrating radar, a roller mechanism of the moving trolley is matched with the arc-shaped groove and slidably connected with the arc-shaped groove, and the ground penetrating radar is arranged above the arc-shaped guide rail and fixed to the moving trolley. The transmitting signal of the radar can be completely reflected to the outer side of the track structure by the inclined plane after being reflected by the inner wall of the tunnel, and the arc surface on the roller mechanism cannot cause signal reflection, so that the superimposed interference of multiple reflection signals and detection signals can be avoided, and the detection accuracy and reliability of the ground penetrating radar can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel wall rear defect detection, and in particular to a radar device for shield tunnel wall rear defect detection. Background Art

[0002] The quality of the secondary lining of highway and railway tunnels is the focus of the tunnel support structure. The grouting quality of the tunnel support structure system is related to the safety of the entire tunnel. Due to the hidden nature of the tunnel lining structure, serious quality problems such as lining voids, insufficient thickness, tunnel water leakage, and secondary lining block loss occur during tunnel construction. Ground penetrating radar, as a non-destructive detection equipment, uses electromagnetic waves to quickly detect the quality of the secondary lining and analyze and judge based on the radar spectrum.

[0003] The time for the grouting behind the tunnel wall to reach a solidified and stable state is a period of time after the assembly of the segments is completed. At this time, the segment ring that needs to be detected is usually in the area of ​​the shield machine trolley. There are trolleys, pipelines and other equipment and tools in this area, and a transportation channel for transporting segments is also required in the middle, resulting in a relatively small available space for the ground penetrating radar. In order to solve the problem of insufficient detection space, a circular track is usually installed on the trolley. The ground penetrating radar can move back and forth on the circular track and scan the segments. The radar's transmitting signal can penetrate the segments, and the transmitting signal can be received by the radar after being reflected by the grouting layer.

[0004] However, the radar's transmitted signal propagates in a fan-shaped manner. When encountering the arc surface on the track structure, part of the signal will be received by the radar after multiple reflections from the inner wall of the segment and the track structure. Limited by the space between the inner wall of the segment and the track structure, the time when the radar receives the reflected signal of the grouting layer is close to the time when the signal after multiple reflections is received, resulting in signal superposition interference, which affects the accuracy and reliability of the detection results. In addition, shield tunnels have turning sections, and the trolleys in the turning sections usually deviate from the central axis of the tunnel, causing the circular track on the trolley to be unable to maintain a concentric state with any section of the tunnel, making the ground penetrating radar detection results inaccurate. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a radar device for detecting defects behind the shield tunnel wall, which can avoid signal superposition interference and improve the detection accuracy and reliability of the ground penetrating radar.

[0006] In order to solve the above technical problems, the present invention provides a radar device for detecting defects behind the shield tunnel wall, comprising: Base; A movable bracket, which is arranged on the base in a horizontally movable manner; A track structure, comprising two mirror-arranged arc guide rails, wherein the arrangement direction of the arc guide rails is the same as the moving direction of the mobile bracket, the arc guide rails are fixed to the mobile bracket, the inner side surface is provided with an arc groove, and the upper surface is provided with an inclined surface facing the outer side of the track structure; The radar detection mechanism comprises a moving trolley and a ground penetrating radar, wherein the roller mechanism of the moving trolley is adapted to the arc groove and is slidably connected to the arc groove, and the ground penetrating radar is arranged above the arc guide rail and fixed on the moving trolley.

[0007] Preferably, in the above scheme, the roller mechanism of the mobile trolley includes a driving wheel, a driven wheel and a telescopic structure, the driving wheel is arranged at the four corners of the mobile trolley and is slidably connected to the inner wall of the arc-shaped groove, the upper end of the telescopic structure is fixedly connected to the mobile trolley, and the lower end is fixedly connected to the rotating shaft of the driven wheel, the driven wheel is arranged below the driving wheel, and is slidably connected to the lower surface of the arc-shaped guide rail.

[0008] Preferably, in the above solution, the telescopic structure is configured as an elastic telescopic rod, and when the driven wheel abuts against the lower surface of the arc-shaped guide rail, the elastic telescopic rod is in a stretched state.

[0009] Preferably, in the above solution, the arc-shaped guide rail further includes a limiting protrusion, and the limiting protrusion is arranged outside the arc-shaped groove, and a spacing is left between the driven wheel and the movable bracket and the limiting protrusion.

[0010] Preferably, in the above scheme, the movable bracket includes a slide plate, a slideway and a support rod, the slide plate and the slideway are adapted to each other and slidably connected, the slideway is fixed on the base, the top ends of the multiple support rods are fixedly connected to the lower surface of the arc track, and the bottom ends are fixedly connected to the upper surface of the slide plate.

[0011] Preferably, in the above scheme, the movable bracket also includes a gear and a rack that mesh with each other and a first motor, the rack is fixed on the skateboard, the first motor is fixed on the slide, and the output end is fixedly connected to the gear for driving the gear to rotate and drive the rack and the skateboard to move left and right in the slide.

[0012] Preferably, in the above scheme, the movable bracket also includes a roller group and a blocking block, the roller group is arranged in the slideway and is slidably connected to the lower surface of the slide plate, and the blocking block is arranged in the middle of the upper surface of the slideway to limit the moving range of the slide plate.

[0013] Preferably, in the above solution, the mobile bracket further includes a first distance sensor, and the first distance sensor is respectively provided on the left and right sides of the skateboard.

[0014] Preferably, in the above scheme, the radar detection mechanism also includes a lifting mechanism and a second distance sensor, the lifting mechanism is fixed on the moving vehicle, the ground penetrating radar is fixed on the lifting mechanism, and the second distance sensors are respectively provided on the left and right sides of the ground penetrating radar.

[0015] Preferably, in the above scheme, the lifting mechanism includes a telescopic rod, a fixed plate and a second motor, the bottom end of the telescopic rod is installed at the top middle position of the moving vehicle, and the top end is installed at the bottom middle position of the fixed plate, the second motor is used to drive the telescopic rod to move up and down, and the ground penetrating radar is installed at the top middle position of the fixed plate.

[0016] Compared with the existing technology, the present invention has the following beneficial effects:

[0017] 1. A radar device for detecting defects behind a shield tunnel wall in the present invention comprises a base, a mobile bracket, a track structure, and a radar detection mechanism, wherein the mobile bracket is arranged on the base in a horizontally movable manner, the track structure comprises two arc guide rails arranged in a mirror image, the arrangement direction of the arc guide rails is the same as the movement direction of the mobile bracket, the arc guide rails are fixed on the mobile bracket, and the track structure is kept concentric with any section of the tunnel by adjusting the horizontal position of the mobile bracket; an arc groove is arranged on the inner side surface of the arc guide rail, and an inclined surface facing the outer side of the track structure is arranged on the upper surface; the radar detection mechanism comprises a mobile trolley and a ground penetrating radar, the roller mechanism of the mobile trolley is adapted to the arc groove and is slidably connected to the arc groove, the ground penetrating radar is arranged above the arc guide rail and fixed on the mobile trolley, the transmission signal of the radar is reflected by the inner wall of the tunnel and will be completely reflected to the outer side of the track structure by the inclined surface, and the arc surface on the roller mechanism of the mobile trolley will not cause signal reflection, and can avoid the superposition interference of multiple reflection signals and detection signals; in summary, the present invention can improve the accuracy and reliability of ground penetrating radar in detecting defects behind a tunnel wall.

[0018] 2. The arc guide rail in the present invention also includes a limiting protrusion, which is arranged on the outside of the arc groove. The limiting protrusion can prevent the rolling paths of the driving wheel and the driven wheel from deviating; the telescopic structure is arranged as an elastic telescopic rod. When the driven wheel abuts against the lower surface of the arc guide rail, the elastic telescopic rod is in a stretched state, and the driven wheel is subjected to the upward pulling force of the elastic telescopic rod and can fit tightly with the lower surface of the arc guide rail, so that the mobile trolley can run more smoothly on the track structure.

[0019] 3. The left and right sides of the slide in the present invention are respectively provided with distance sensors for detecting the distance between the left and right sides of the slide and the inner wall of the tunnel in real time, so as to adjust the horizontal position of the mobile bracket in real time, so that the track structure and any section of the tunnel remain concentric, and a blocking block is provided in the middle of the upper surface of the slide to limit the moving range of the slide and prevent the mobile bracket from detaching from the base when moving.

[0020] 4. The radar detection mechanism in the present invention also includes a lifting mechanism and a second distance sensor. The lifting mechanism is fixed on the mobile trolley, and the ground penetrating radar is fixed on the lifting mechanism. The lifting mechanism is used to adjust the distance between the ground penetrating radar and the inner wall of the tunnel. The left and right sides of the ground penetrating radar are respectively provided with second distance sensors, which can prevent the ground penetrating radar from scratching the protrusions on the inner wall of the tunnel during movement and avoid obstacles on the left and right sides of the ground penetrating radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a schematic structural diagram of a radar device for detecting defects behind a shield tunnel wall.

[0022] Figure 2 It is a schematic diagram of the installation structure of the mobile bracket and the track structure of the present invention.

[0023] Figure 3 It is a schematic structural diagram of the radar detection mechanism of the present invention.

[0024] Figure 4 It is a schematic diagram of the installation structure of the base and the slideway of the present invention.

[0025] Among them, 1-base, 11-bolt hole, 2-movable bracket, 21-skateboard, 22-slide, 23-support rod, 24-gear, 25-rack, 26-first motor, 27-roller group, 28-blocking block, 29-first distance sensor, 3-track structure, 31-arc guide rail, 311-arc groove, 312-inclined surface, 313-limiting protrusion, 4-radar detection mechanism, 41-moving trolley, 411-driving wheel, 412-driven wheel, 413-telescopic structure, 42-ground penetrating radar, 43-lifting mechanism, 431-telescopic rod, 432-fixed plate, 433-second motor, 44-second distance sensor. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0028] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If the terms "first", "second", "third" are described, they are only used for the purpose of description and distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The following is an explanation of the embodiments of the present invention based on its overall structure.

[0030] like Figure 1 , Figure 2 As shown, the present invention discloses a radar device for detecting defects behind the shield tunnel wall, comprising a base 1, a mobile bracket 2, a track structure 3, and a radar detection mechanism 4, wherein the mobile bracket 2 is horizontally movably arranged on the base 1, the track structure 3 comprises two arc guide rails 31 arranged in a mirror image, the arrangement direction of the arc guide rails 31 is the same as the moving direction of the mobile bracket 2, the arc guide rails 31 are fixed to the mobile bracket 2, the inner side surface is provided with an arc groove 311, and the upper surface is provided with an inclined surface 312 facing the outer side of the track structure 3, the radar detection mechanism 4 comprises a mobile trolley 41 and a ground penetrating radar 42, the roller mechanism of the mobile trolley 41 is mutually adapted to the arc groove 311, and is slidably connected to the arc groove 311, and the ground penetrating radar 42 is arranged above the arc guide rail 31 and fixed on the mobile trolley 41.

[0031] It can be understood that in this embodiment, the upper surface of the arc guide rail 31 is provided with an inclined surface 312 facing the outside of the track structure 3, and the ground penetrating radar 42 is arranged above the arc guide rail 31. The radar's transmission signal will be completely reflected to the outside of the track structure 3 by the inclined surface 312 after being reflected by the inner wall of the tunnel, which can avoid the superposition interference of multiple reflection signals and detection signals; and the roller mechanism of the mobile trolley 41 is mutually adapted to the arc groove 311, and is slidingly connected to the arc groove 311, which can avoid the arc surface on the roller mechanism causing signal reflection interference; in addition, the setting direction of the arc guide rail 31 is the same as the moving direction of the mobile bracket 2, and the horizontal position of the mobile bracket 2 is adjusted to make the track structure 3 and any section of the tunnel remain concentric; in summary, the present invention can improve the accuracy and reliability of ground penetrating radar in detecting tunnel wall defects.

[0032] Continue to refer Figure 3 The roller mechanism of the moving trolley 41 in this embodiment includes a driving wheel 411, a driven wheel 412 and a telescopic structure 413. The driving wheel 411 is arranged at the four corners of the moving trolley 41 and is slidably connected to the inner wall of the arc groove 311. The upper end of the telescopic structure 413 is fixedly connected to the moving trolley 41, and the lower end is fixedly connected to the rotating shaft of the driven wheel 412. The driven wheel 412 is arranged below the driving wheel 411 and is slidably connected to the lower surface of the arc guide rail 31.

[0033] Specifically, the arc guide rail 31 also includes a limiting protrusion 313, which is arranged on the outside of the arc groove 311. There is a distance between the driven wheel 412 and the movable bracket 2 and the limiting protrusion 313. The limiting protrusion 313 can prevent the rolling paths of the driving wheel 411 and the driven wheel 412 from deviating.

[0034] It is worth noting that the telescopic structure 413 is configured as an elastic telescopic rod. When the driven wheel 412 abuts against the lower surface of the arc guide rail 31, the elastic telescopic rod is in a stretched state, and the driven wheel 412 is subjected to the upward pulling force of the elastic telescopic rod and can fit tightly with the lower surface of the arc guide rail 31, so that the moving trolley 41 runs more smoothly on the track structure 3.

[0035] Continue to refer Figure 4 The mobile bracket 2 includes a slide plate 21, a slideway 22 and a support rod 23. The slide plate 21 and the slideway 22 are adapted to each other and slidably connected. The slideway 22 is fixed on the base 1. The top ends of the support rods 23 are fixedly connected to the lower surface of the arc track 31, and the bottom ends are fixedly connected to the upper surface of the slide plate 21. Specifically, the slide plate 21 is a square structure, the slideways 22 are respectively arranged in front and behind the slide plate 21, and a support rod 23 is respectively arranged at the four corners of the upper surface of the slide plate 21. There is a gap between the driven wheel 412 and the support rod 23, and the driven wheel 412 will not be affected by the support rod 23 when rolling on the lower surface of the arc guide rail 31.

[0036] Furthermore, the mobile bracket 2 further includes a gear 24 and a rack 25 meshing with each other and a first motor 26, the rack 25 is fixed on the slide 21, the first motor 26 is fixed on the slide 22, and the output end is fixedly connected to the gear 24, used to drive the gear 24 to rotate, and drive the rack 25 and the slide 21 to move left and right in the slide 22. Specifically, the rack 25 is fixed to the front surface of the slide 21, the first motor 26 is fixed to the middle position of the upper surface of the slide 22 above the rack 25, and the output end penetrates the slide 22 and is fixedly connected to the gear 24 coaxially.

[0037] Furthermore, the mobile bracket 2 also includes a roller group 27 and a blocking block 28. The roller group 27 is arranged in the slideway 22 and is slidably connected to the lower surface of the slide plate 21. The blocking block 28 is arranged in the middle of the upper surface of the slideway 22 to limit the moving range of the slide plate 21. Specifically, the blocking block 28 extends from the outer side to the inner side of the slide plate 21. When the slide plate 21 moves left and right in the slideway 22, the support rod 23 will be blocked by the blocking block 28, thereby achieving the purpose of limiting the left and right moving range of the slide plate 21 and preventing the mobile bracket 2 from being separated from the base 1 when moving. The base 1 is provided with an oblong bolt hole 11, so that the base 1 can be fixedly installed on the trolley by bolts.

[0038] Furthermore, the mobile bracket 2 also includes a first distance sensor 29, and the first distance sensors 29 are respectively provided on the left and right sides of the skateboard 21, which are used to detect the distance between the left and right sides of the skateboard 21 and the inner wall of the tunnel in real time, so as to adjust the horizontal position of the mobile bracket 2 in real time, so that the track structure 3 and any section of the tunnel remain concentric.

[0039] The radar detection mechanism 4 in this embodiment also includes a lifting mechanism 43 and a second distance sensor 44. The lifting mechanism 43 is fixed on the moving trolley 41, and the ground penetrating radar 42 is fixed on the lifting mechanism 43. The lifting mechanism 43 is used to adjust the distance between the ground penetrating radar 42 and the inner wall of the tunnel. The left and right sides of the ground penetrating radar 32 are respectively provided with second distance sensors 44, which can detect obstacles on the left and right sides in real time during the movement of the ground penetrating radar 32 to avoid scratches between the protrusions on the inner wall of the tunnel and the ground penetrating radar 32.

[0040] Specifically, the lifting mechanism 43 includes a telescopic rod 431, a fixed plate 432 and a second motor 433. The bottom end of the telescopic rod 431 is installed at the top middle position of the moving trolley 41, and the top end is installed at the bottom middle position of the fixed plate 432. The second motor 433 is used to drive the telescopic rod 431 to move up and down. The ground penetrating radar 42 is installed at the top middle position of the fixed plate 432. The fixed plate 432 can block the reflected signal from below from being received by the ground penetrating radar 42.

[0041] It is worth noting that the left and right sides of the mobile trolley 41 are provided with inclined surfaces facing outwards, and the left and right inclined surfaces of the mobile trolley 41 are respectively provided with second distance sensors 44. By setting the angle of the inclined surface, it is ensured that when the fixing plate 432 is in the lowest position, it will not block the second distance sensor 44 from detecting the inner wall of the tunnel, and the distance between the inner wall of the tunnel above the left and right sides of the mobile trolley 41 and the mobile trolley 41 can be detected in real time. The control system accurately controls the up and down movement distance of the telescopic rod 431 through the second motor 433, so that the distance between the ground penetrating radar 42 and the inner wall of the tunnel meets the safety threshold, and the ground penetrating radar 42 can be prevented from scratching the protrusions of the inner wall of the tunnel during movement, and avoid obstacles appearing above the left and right sides of the mobile trolley 41. The above-mentioned distance sensor is preferably an infrared ranging sensor or a laser ranging sensor. If an ultrasonic ranging sensor is used, it is necessary to use a signal of a different frequency from the ground penetrating radar 42 to avoid interference with the received signal.

[0042] Thus, the functions of a radar device for detecting defects behind a shield tunnel wall in this embodiment are as follows:

[0043] (1) Avoid reflection interference function An arc-shaped groove is provided on the inner side of the arc-shaped guide rail, and an inclined surface is provided on the upper surface toward the outer side of the track structure. The radar detection mechanism includes a moving trolley and a ground-penetrating radar. The roller mechanism of the moving trolley is adapted to the arc-shaped groove and is slidably connected to the arc-shaped groove. The ground-penetrating radar is arranged above the arc-shaped guide rail and fixed on the moving trolley. The radar's transmission signal will be completely reflected to the outer side of the track structure by the inclined surface after being reflected by the inner wall of the tunnel. Moreover, the arc surface on the roller mechanism of the moving trolley will not cause signal reflection, thereby avoiding the superposition interference of multiple reflection signals and detection signals.

[0044] (2) Horizontal movement function The movable bracket is horizontally movably arranged on the base, the track structure includes two arc guide rails arranged in a mirror image, the setting direction of the arc guide rails is the same as the moving direction of the movable bracket, the arc guide rails are fixed on the movable bracket, and the track structure is kept concentric with any section of the tunnel by adjusting the horizontal position of the movable bracket.

[0045] (3) Smooth movement function By arranging the limiting protrusion on the outside of the arc-shaped groove, the rolling paths of the driving wheel and the driven wheel can be prevented from deviating; when the driven wheel abuts against the lower surface of the arc-shaped guide rail, the elastic telescopic rod is in a stretched state, and the driven wheel is subjected to the upward pulling force of the elastic telescopic rod, and can fit tightly with the lower surface of the arc-shaped guide rail, so that the mobile trolley can run more smoothly on the track structure.

[0046] (4) Concentric state adjustment function Distance sensors are provided on the left and right sides of the slide respectively to detect the distance between the left and right sides of the slide and the inner wall of the tunnel in real time, so as to adjust the horizontal position of the mobile bracket in real time and keep the track structure concentric with any section of the tunnel.

[0047] (5) Obstacle detection function By setting up the lifting mechanism and the second distance sensor, it is possible to avoid the ground penetrating radar from scratching against the protrusions on the inner wall of the tunnel during movement, and avoid obstacles that appear above the left and right sides of the moving vehicle.

[0048] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A radar device for detecting defects behind a shield tunnel wall, characterized in that: include: Base; A movable bracket, which is arranged on the base in a horizontally movable manner; A track structure, comprising two mirror-arranged arc guide rails, wherein the arrangement direction of the arc guide rails is the same as the moving direction of the mobile bracket, the arc guide rails are fixed to the mobile bracket, the inner side surface is provided with an arc groove, and the upper surface is provided with an inclined surface facing the outer side of the track structure; The radar detection mechanism comprises a moving trolley and a ground penetrating radar, wherein the roller mechanism of the moving trolley is adapted to the arc groove and is slidably connected to the arc groove, and the ground penetrating radar is arranged above the arc guide rail and fixed on the moving trolley.

2. A radar device for detecting defects behind a shield tunnel wall according to claim 1, characterized in that: The roller mechanism of the mobile trolley includes a driving wheel, a driven wheel and a telescopic structure. The driving wheel is arranged at the four corners of the mobile trolley and is slidably connected to the inner wall of the arc-shaped groove. The upper end of the telescopic structure is fixedly connected to the mobile trolley, and the lower end is fixedly connected to the rotating shaft of the driven wheel. The driven wheel is arranged below the driving wheel and is slidably connected to the lower surface of the arc-shaped guide rail.

3. A radar device for detecting defects behind a shield tunnel wall according to claim 2, characterized in that: The telescopic structure is configured as an elastic telescopic rod, and when the driven wheel abuts against the lower surface of the arc-shaped guide rail, the elastic telescopic rod is in a stretched state.

4. A radar device for detecting defects behind a shield tunnel wall according to claim 2, characterized in that: The arc-shaped guide rail further includes a limiting protrusion, which is arranged outside the arc-shaped groove, and a spacing is left between the driven wheel, the movable bracket and the limiting protrusion.

5. The radar device for detecting defects behind the shield tunnel wall according to claim 1, characterized in that: The movable bracket includes a slide plate, a slideway and a support rod. The slide plate and the slideway are adapted to each other and slidably connected. The slideway is fixed on the base. The top ends of the multiple support rods are fixedly connected to the lower surface of the arc track, and the bottom ends are fixedly connected to the upper surface of the slide plate.

6. A radar device for detecting defects behind a shield tunnel wall according to claim 5, characterized in that: The mobile bracket also includes a gear and a rack that mesh with each other and a first motor. The rack is fixed on the skateboard, and the first motor is fixed on the slideway. The output end is fixedly connected to the gear to drive the gear to rotate and drive the rack and the skateboard to move left and right in the slideway.

7. A radar device for detecting defects behind a shield tunnel wall according to claim 6, characterized in that: The movable bracket also includes a roller group and a blocking block. The roller group is arranged in the slideway and is slidably connected to the lower surface of the slide plate. The blocking block is arranged in the middle of the upper surface of the slideway to limit the moving range of the slide plate.

8. A radar device for detecting defects behind a shield tunnel wall according to claim 6, characterized in that: The mobile bracket also includes a first distance sensor, and the first distance sensors are respectively arranged on the left and right sides of the skateboard.

9. A radar device for detecting defects behind a shield tunnel wall according to claim 1, characterized in that: The radar detection mechanism also includes a lifting mechanism and a second distance sensor. The lifting mechanism is fixed on the moving vehicle. The ground penetrating radar is fixed on the lifting mechanism. The second distance sensors are respectively arranged on the left and right sides of the ground penetrating radar.

10. A radar device for detecting defects behind a shield tunnel wall according to claim 9, characterized in that: The lifting mechanism includes a telescopic rod, a fixed plate and a second motor. The bottom end of the telescopic rod is installed at the middle position of the top of the mobile vehicle, and the top end is installed at the middle position of the bottom of the fixed plate. The second motor is used to drive the telescopic rod to move up and down. The ground penetrating radar is installed at the middle position of the top of the fixed plate.

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