Underground cavity 3D imaging equipment

Abstract

The invention discloses an underground cavity 3D imaging device, and relates to the technical field of underground cavity detection, the underground cavity 3D imaging device comprises a main body frame with a brake wheel at the bottom, and the main body frame is internally provided with a lifting assembly, a detection assembly, a hole protection assembly and a display terminal assembly; the detection assembly comprises a guide rod which is vertically arranged; through the design of the frustum protection cylinder and the air bag, hole collapse or foreign matter invasion can be effectively prevented, the device can be attached to the wall face of a hole through air pressure self-adaptive adjustment, and the safety and stability of the detection process are guaranteed; meanwhile, the arranged frustum protection cylinder can be close to and aligned with the hole so that the position of the device can be adjusted before detection, on the other hand, after detection is finished, the detection head can be retracted through the frustum protection cylinder firstly, and then the frustum protection cylinder is lifted, so that an effective protection effect can be formed on the detection head in the detection process, and the detection efficiency is improved. And meanwhile, collapse of the detection hole is effectively prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of underground cavity detection, and in particular to an underground cavity 3D imaging device. Background Art

[0002] In the traditional work process, it is difficult to accurately obtain the volume and morphological information of the cavity by measurement with a ruler, and it is impossible to enter the interior of the cavity for fine scanning. For the inducing causes and process analysis of cavity formation and some cavities that need to be grouted and repaired, the lack of accurate geometric information will lead to deviations in the analysis of inducing causes and the derivation of the cavity formation process. At the same time, problems such as unreasonable design parameters, insufficient or excessive grouting will occur during cavity grouting; to solve the above problems, the prior art often uses a probe to detect the interior of the cavity to provide visual data support for the grouting repair project of underground cavities.

[0003] In the prior art, detection devices (especially their front-end precision sensing components, such as lenses, radar transmitting / receiving units) usually lack effective guiding and protection mechanisms. During the process of lowering or retrieving the device along the drill hole, especially when the hole wall of the drill hole is irregular, there are sharp protrusions or loose gravel, the outer surface of the detection device is extremely likely to rub or collide with the hole wall. Such scratches will cause minor wear to the device shell, affecting its appearance and service life; in severe cases, it may directly damage key optical lenses, electromagnetic wave transmission windows or sensor surfaces, resulting in a serious decline in imaging quality, signal distortion or device malfunction, directly affecting the accuracy and reliability of detection results. At the same time, after the hole is drilled, the soil stability near the hole opening and the hole wall decreases, especially for loose or water-rich strata. The support structures of existing detection devices often only consider the connection and signal transmission of the device itself (such as simple rigid rods or cables), and lack effective support and reinforcement for the hole opening. During the operation of the device (such as lowering, lifting, slight rotation) or under slight external disturbances (such as personnel walking, device vibration), the loose soil at the hole opening is extremely likely to collapse; the collapse of the hole opening will not only block the passage, resulting in expensive detection devices being buried and difficult to recover, causing property losses; more seriously, the sudden collapse may also threaten the safety of on-site operators and interrupt the entire detection and verification process; therefore, there are limitations. Summary of the Invention

[0004] The purpose of the present invention is to provide an underground cavity 3D imaging device to solve the problems raised in the above background art.

[0005] The technical solution of the present invention is: an underground cavity D imaging device, including a main frame with a brake wheel installed at the bottom, and a lifting component, a detection component, a hole opening protection component and a display terminal component are installed in the main frame; The detection component includes a vertically arranged guide rod, and a detection head is arranged at the bottom end of the guide rod; The hole protection component includes a conical protection cylinder coaxially arranged with the guide rod, and an annular cavity plate is fixed to the top of the conical protection cylinder. A plurality of air bags are fixed on the outer peripheral wall of the conical protection cylinder at equal intervals. A plurality of ventilation cavity paths are arranged in the conical protection cylinder at equal intervals, and both ends of the ventilation cavity path are communicated with the annular cavity plate and the air bag respectively; The display terminal component includes a mounting plate fixed on the main body frame, and an arc-shaped protective cover is fixed on the mounting plate. A torsion spring shaft is arranged in the arc-shaped protective cover, a turning plate is fixed on the torsion spring shaft, and a processing terminal is fixedly arranged on one side of the turning plate.

[0006] Preferably, the lifting component includes two pairs of mounting blocks fixedly installed on the main body frame, and a lead screw is rotatably installed on each pair of mounting blocks. A moving cross bar is commonly connected to the two lead screws through threads, and the middle end of the moving cross bar is fixedly connected to the guide rod.

[0007] Preferably, a pair of end cylinders are fixed to the bottom of the moving cross bar, and a piston rod is slidably installed in the end cylinder. An ear plate is fixed between the bottom end of the piston rod and the conical protection cylinder.

[0008] Preferably, a pair of air holes one and a pair of air holes two are formed on each end cylinder. The air hole one is directly above the air hole two. A spiral air pipe is fixedly communicated with both end cylinders, and the spiral air pipe is spirally sleeved outside the end cylinder and the piston rod. The bottom end of the spiral air pipe is fixedly communicated with the annular cavity plate, and a connecting spring is fixed between the top of the piston rod and the top end of the end cylinder.

[0009] Preferably, a pair of guide rods are fixed at the position of the main body frame close to the mounting plate, and an extension side rod is sleeved on the guide rod. The end of the extension side rod is fixed on the moving cross bar.

[0010] Preferably, a folded rack is fixed on one side of both extension side rods. A transmission shaft is rotatably installed at one end close to the bottom of both sides of the mounting plate. A second transmission belt is sleeved between the transmission shaft and the torsion spring shaft, and a transmission gear adapted to the folded rack is fixed on the transmission shaft.

[0011] Preferably, a driving motor is fixed on one side of the main body frame, and the output shaft of the driving motor is fixedly connected to one of the lead screws.

[0012] Preferably, transmission wheels are fixed to the top ends of both lead screws. A pair of side wheels are installed at one end close to the top of the main body frame. A first transmission belt is sleeved on both transmission wheels and both side wheels.

[0013] Preferably, a signal line is fixed to the top of the guide rod. The signal line is spiral, and both ends of the signal line are electrically connected to the detection head and the processing terminal respectively.

[0014] Preferably, two side guard plates are fixed between one side of the main body frame and the mounting plate, a pair of transparent side plates are fixed on the other three sides of the main body frame, and a top cover is connected to the top of the main body frame through a hinge.

[0015] The present invention provides an underground cavity 3D imaging device through improvement. Compared with the prior art, it has the following improvements and advantages: First: Through the design of the frustum protection cylinder and the airbag, the present invention can not only effectively prevent the cave entrance from collapsing or foreign objects from invading, but also adaptively adjust the air pressure to fit the cave entrance wall surface, ensuring the safety and stability of the detection process; at the same time, by using the provided frustum protection cylinder, it can first approach and align with the cave entrance, so as to adjust the position of the device before detection. On the other hand, after the detection is completed, the detection head can first retract through the frustum protection cylinder, and then the frustum protection cylinder is lifted. Therefore, during the detection process, the detection head can be effectively protected, and at the same time, the collapse of the detection cave entrance can be effectively prevented. Second: By using the provided torsion spring shaft and the flip plate, the present invention facilitates flipping the processing terminal to the outside of the device during detection to avoid information display; after detection, the processing terminal will reset to the inside of the arc-shaped protective cover under the action of the torsion spring shaft, thereby realizing the effective protection of the processing terminal and information. Third: The frustum protection cylinder provided in the present invention is located outside the detection head and can play a protective role in the process of extending into the cave entrance to prevent the detection head from scratching against the cave entrance; when the frustum protection cylinder is inserted into the cave, the moving cross bar continues to move downward, while the frustum protection cylinder stays at the cave entrance position. At the same time, the end cylinder moves downward relative to the piston rod. When the piston rod moves above the air hole 1, the air in the upper part of the end cylinder can be input into the annular cavity plate through the spiral air pipe, and with the provided air ventilation cavity path, the airbag expands, thereby strengthening the support for the cave entrance. In addition, this design also enables the outer diameter of the frustum protection cylinder to be smaller than the inner diameter of the detection cave entrance, facilitating the insertion of the frustum protection cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 It is a schematic three-dimensional structure diagram of the whole of the present invention; Figure 2 It is a schematic diagram of the unfolded top cover and the exploded structure of the side guard plates of the present invention; Figure 3Schematic diagram of the internal structure of the main frame of the present invention; Figure 4 Schematic diagram of the three-dimensional structure of the frustum protection cylinder of the present invention; Figure 5 Schematic diagram of the partial sectional structure of the main frame of the present invention; Figure 6 Schematic diagram of the sectional structure of the arc-shaped protective cover of the present invention; Figure 7 Schematic diagram of the three-dimensional structure of the transmission shaft and transmission gear of the present invention; Figure 8 Schematic diagram of the three-dimensional structure of the lead screw and guide rod of the present invention; Figure 9 For the present invention Figure 8 Enlarged structure diagram at position A in; Figure 10 For the present invention Figure 8 Enlarged structure diagram at position B in.

[0018] Reference numerals: 1. Main frame; 2. Transparent side plate; 3. Brake wheel; 4. Mounting plate; 5. Flipping plate; 6. Torsion spring shaft; 7. Arc-shaped protective cover; 8. Top cover; 9. Side guard plate; 10. Guide rod; 11. Signal wire; 12. Lead screw; 13. Moving cross bar; 14. First transmission belt; 15. Second transmission belt; 16. Transmission gear; 17. Transmission shaft; 18. Folded rack; 19. Extended side rod; 20. Guide rail; 21. Driving motor; 22. Processing terminal; 23. End cylinder; 24. Piston rod; 25. Connecting spring; 26. First air hole; 27. Second air hole; 28. Spiral air pipe; 29. Ear plate; 30. Annular cavity plate; 31. Frustum protection cylinder; 32. Ventilation cavity path; 33. Air bag; 34. Detection head; 35. Mounting block; 36. Transmission wheel; 37. Side wheel. Detailed implementation manners

[0019] The present invention will be described in detail below. The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] The present invention provides an underground cavity 3D imaging device by making improvements. The technical solution of the present invention is as follows: As Figures 1 to 10 shown, an underground cavity 3D imaging device provided by an embodiment of the present invention includes a main frame 1 with a brake wheel 3 installed at the bottom. A lifting assembly, a detection assembly, a hole protection assembly, and a display terminal assembly are installed in the main frame 1; The detection component includes a vertically arranged guide rod 10, and a detection head 34 is provided at the bottom end of the guide rod 10; the detection head 34 supports 360° circumferential scanning and has an omnidirectional transmitting and receiving function. Specifically, it can actively emit high-frequency electromagnetic pulses and collect reflected signals in all directions to form an echo data set at multiple angles.

[0021] The hole protection component includes a frustum-shaped protection cylinder 31 coaxially arranged with the guide rod 10, and an annular cavity plate 30 is fixed at the top of the frustum-shaped protection cylinder 31. A plurality of air bags 33 are evenly distributed and fixed on the outer peripheral wall of the frustum-shaped protection cylinder 31. A plurality of evenly distributed ventilation cavity paths 32 are provided inside the frustum-shaped protection cylinder 31. Both ends of the ventilation cavity paths 32 are respectively communicated with the annular cavity plate 30 and the air bags 33; with the above structure, through the design of the frustum-shaped protection cylinder 31 and the air bags 33, it can not only effectively prevent the collapse of the hole or the intrusion of foreign objects, but also adaptively adjust the air pressure to fit the hole wall surface, ensuring the safety and stability of the detection process. At the same time, by using the provided frustum-shaped protection cylinder 31, it can first approach and align with the hole to facilitate the adjustment of the position of the device before detection. On the other hand, after the detection is completed, the detection head 34 can first retract through the frustum-shaped protection cylinder 31, and then the frustum-shaped protection cylinder 31 is lifted, so that during the detection process, an effective protective effect can be formed on the detection head 34.

[0022] The display terminal component includes a mounting plate 4 fixed on the main body frame 1, and an arc-shaped protective cover 7 is fixed on the mounting plate 4. A torsion spring shaft 6 is arranged inside the arc-shaped protective cover 7, and a turning plate 5 is fixed on the torsion spring shaft 6. A processing terminal 22 is fixedly arranged on one side of the turning plate 5. The processing terminal 22 is used to receive and process the hole echo signal, and through the display screen equipped with the processing terminal 22, the three-dimensional model and parameter report of the hole are displayed. By using the provided torsion spring shaft 6 and turning plate 5, it is convenient to turn the processing terminal 22 to the outside of the device during detection to avoid information display; after detection, the processing terminal 22 will reset to the inside of the arc-shaped protective cover 7 under the action of the torsion spring shaft 6, so as to effectively protect the processing terminal 22 and the information.

[0023] Furthermore, the lifting component includes two pairs of mounting blocks 35 fixedly installed on the main body frame 1, and a lead screw 12 is rotatably installed on each pair of mounting blocks 35. A moving cross bar 13 is commonly connected to the two lead screws 12 through threads, and the middle end of the moving cross bar 13 is fixedly connected to the guide rod 10; with the above structure, the provided lead screw 12 can drive the moving cross bar 13 to lift, ensuring the vertical movement of the guide rod 10, avoiding the deviation of the detection head 34, and preventing the detection head 34 and foreign objects from being collided.

[0024] As a further solution of the present invention, as Figures 8 - 10As shown, a pair of end cylinders 23 are fixed to the bottom of the moving crossbar 13, and a piston rod 24 is slidably installed in the end cylinder 23. An ear plate 29 is fixed between the bottom end of the piston rod 24 and the frustum-shaped protective cylinder 31.

[0025] Furthermore, a pair of first air holes 26 and a pair of second air holes 27 are formed in each end cylinder 23. The first air holes 26 are located directly above the second air holes 27. A spiral air pipe 28 is fixedly communicated with both end cylinders 23, and the spiral air pipe 28 is spirally sleeved outside the end cylinder 23 and the piston rod 24. The bottom end of the spiral air pipe 28 is fixedly communicated with the annular cavity plate 30. A connecting spring 25 is fixed between the top of the piston rod 24 and the top end of the end cylinder 23.

[0026] With the above structure, during detection, the moving crossbar 13 moves downward. As shown in the attachment Figures 3 - 5 As shown, the provided frustum-shaped protective cylinder 31 is located outside the detection head 34 and can protect the detection head 34 during the process of extending into the hole, avoiding scratching between the detection head 34 and the hole. When the frustum-shaped protective cylinder 31 is inserted into the hole, the moving crossbar 13 continues to move downward, while the frustum-shaped protective cylinder 31 stays at the hole position. At the same time, the end cylinder 23 moves downward relative to the piston rod 24. When the piston rod 24 moves above the first air holes 26, the air in the upper part of the end cylinder 23 can be input into the annular cavity plate 30 through the spiral air pipe 28, and in cooperation with the provided ventilation cavity path 32, the airbag 33 expands, thereby strengthening the support for the hole. In addition, this design also enables the outer diameter of the frustum-shaped protective cylinder 31 to be smaller than the inner diameter of the detection hole, facilitating the insertion of the frustum-shaped protective cylinder 31.

[0027] Furthermore, a pair of guide rods 20 are fixed at the position of the main body frame 1 close to the mounting plate 4, and an extended side rod 19 is sleeved on the guide rod 20. The end of the extended side rod 19 is fixed to the moving crossbar 13. By using the cooperation of the provided guide rod 20 and the extended side rod 19, the moving stability of the moving crossbar 13 can be further improved.

[0028] As a further solution of the present invention, as shown in Figures 4 - 7 As shown, a folded rack 18 is fixed to one side of each of the two extended side rods 19. A transmission shaft 17 is rotatably installed at one end near the bottom of both sides of the mounting plate 4. A second transmission belt 15 is sleeved between the transmission shaft 17 and the torsion spring shaft 6. A transmission gear 16 adapted to the folded rack 18 is fixed on the transmission shaft 17. With the above structure, during detection, the moving crossbar 13 moves downward and synchronously drives the extended side rod 19 to move downward synchronously. When the folded rack 18 contacts the transmission gear 16, it can push the transmission shaft 17 to rotate, and then through the transmission of the second transmission belt 15, drive the torsion spring shaft 6 and the processing terminal 22 to flip.

[0029] Further, a driving motor 21 is fixed on one side of the main body frame 1, and the output shaft of the driving motor 21 is fixedly connected to one of the lead screws 12.

[0030] Further, transmission wheels 36 are fixed to the tops of both lead screws 12, and a pair of side wheels 37 are installed at one end of the main body frame 1 close to the top. A first transmission belt 14 is sleeved on the two transmission wheels 36 and the two side wheels 37 together; through the above structure, when the driving motor 21 is started, the lead screw 12 connected thereto can be driven to rotate. At the same time, through the action of the first transmission belt 14, the side wheels 37 and the transmission wheels 36, the two lead screws 12 rotate synchronously. At the same time, the first transmission belt 14 can be moved away from the guide rod 10 to avoid interfering with the movement of the guide rod 10.

[0031] As a further solution of the present invention, as Figures 2 - 5 shown, a signal line 11 is fixed to the top of the guide rod 10. The signal line 11 is spiral. One section of the signal line 11 is embedded in the guide rod 10 for power supply and signal transmission. The two ends of the signal line 11 are electrically connected to the detection head 34 and the processing terminal 22 respectively; through the above structure, the detection head 34 scans circumferentially in the cavity, and the data is transmitted to the processing terminal 22 through the signal line 11.

[0032] Further, as Figures 1 - 3 shown, two side protection plates 9 are fixed between one side of the main body frame 1 and the mounting plate 4, and a pair of transparent side plates 2 are fixed on the other three sides of the main body frame 1. The top end of the main body frame 1 is hinged with a top cover 8; through the above structure, the provided side protection plates 9 and transparent side plates 2, together with the top cover 8, protect the device.

[0033] The specific working method is as follows: When in use, the device can be moved to the drilled detection hole. By using the provided frustum-shaped protective cylinder 31, it can first approach and align with the hole to facilitate adjusting the position of the device before detection. When the frustum-shaped protective cylinder 31 is aligned with the hole, the belt brake wheels 3 under the device can be braked, and the driving motor 21 can be started to drive the lead screw 12 connected thereto to rotate. At the same time, through the action of the first transmission belt 14, the side wheels 37 and the transmission wheels 36, the two lead screws 12 rotate synchronously, thereby driving the moving cross bar 13 to move up and down to ensure the vertical movement of the guide rod 10, avoid the deviation of the detection head 34, and prevent the detection head 34 from colliding with external objects; when detecting, the moving cross bar 13 moves downward, as shown in the appendix Figures 3 - 5As shown, the provided frustum-shaped protective cylinder 31 is located outside the detection head 34, and can play a protective role for the detection head 34 during the process of extending into the hole, avoiding scratching between the detection head 34 and the hole; when the frustum-shaped protective cylinder 31 is inserted into the hole, the moving cross bar 13 continues to move downward, while the frustum-shaped protective cylinder 31 stays at the position of the hole. At the same time, the end cylinder 23 moves downward relative to the piston rod 24. When the piston rod 24 moves above the air hole 1, part of the air in the upper part of the end cylinder 23 can be input into the annular cavity plate 30 through the spiral air pipe 28, and cooperate with the provided air ventilation cavity path 32 to make the airbag 33 expand, thus strengthening the support for the hole; at the same time, during detection, the moving cross bar 13 moves downward and synchronously drives the extension side bar 19 to move downward synchronously. When the folded rack 18 contacts the transmission gear 16, it can push the transmission shaft 17 to rotate, and then drive the torsion spring shaft 6 and the processing terminal 22 to flip through the transmission of the second transmission belt 15, facilitating the flipping of the processing terminal 22 to the outside of the device during detection to avoid information display. During the detection process, the detection head 34 performs a 360° circumferential scan, can actively emit high-frequency electromagnetic pulses and collect reflected signals in all directions to form a multi-angle echo data set; while the processing terminal 22 receives and processes the cavity echo signal, and displays the cavity three-dimensional model and parameter report through the display screen equipped on the processing terminal 22; after detection, the processing terminal 22 will be reset inside the arc-shaped protective cover 7 under the action of the torsion spring shaft 6, thus realizing the effective protection of the processing terminal 22 and information; at the same time, after detection, the provided moving cross bar 13 will move upward and first drive the detection head 34 to move upward. During this process, the end cylinder 23 moves upward relative to the piston rod 24, thus forming a negative pressure and making the airbag 33 contract. When the moving cross bar 13 is completely reset, the provided frustum-shaped protective cylinder 31 is sleeved outside the detection head 34 and forms a protective effect on the detection head 34 again.

[0034] The above description enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An underground cavity 3D imaging device, comprising a main body frame (1) with a brake wheel (3) installed at the bottom, characterized in that, A lifting component, a detection component, a hole protection component and a display terminal component are installed in the main body frame (1); the detection component includes a vertically arranged guide rod (10), and a detection head (34) is arranged at the bottom end of the guide rod (10). The hole protection component includes a conical protection cylinder (31) coaxially arranged with the guide rod (10), and an annular cavity plate (30) is fixed at the top of the conical protection cylinder (31). A plurality of air bags (33) are fixed on the outer peripheral wall of the conical protection cylinder (31) at equal intervals. A plurality of ventilation cavity paths (32) are arranged in the conical protection cylinder (31) at equal intervals, and both ends of the ventilation cavity path (32) are respectively communicated with the annular cavity plate (30) and the air bag (33); the display terminal component includes a mounting plate (4) fixed on the main body frame (1), and an arc-shaped protective cover (7) is fixed on the mounting plate (4). A torsion spring shaft (6) is arranged in the arc-shaped protective cover (7), a turning plate (5) is fixed on the torsion spring shaft (6), and a processing terminal (22) is fixedly arranged on one side of the turning plate (5).

2. The 3D imaging device for underground cavities according to claim 1, wherein: The lifting component includes two pairs of mounting blocks (35) fixedly installed on the main body frame (1), and a lead screw (12) is rotatably installed on each pair of mounting blocks (35). A moving cross bar (13) is commonly connected to the two lead screws (12) through threads, and the middle end of the moving cross bar (13) is fixedly connected to the guide rod (10).

3. The 3D imaging device for underground cavities according to claim 2, characterized in that: A pair of end cylinders (23) are fixed at the bottom of the moving cross bar (13), and a piston rod (24) is slidably installed in the end cylinder (23). An ear plate (29) is fixed between the bottom end of the piston rod (24) and the conical protection cylinder (31).

4. The 3D imaging device for underground cavities according to claim 3, characterized in that: A pair of air holes one (26) and a pair of air holes two (27) are formed in each end cylinder (23). The air hole one (26) is located directly above the air hole two (27). A spiral air pipe (28) is fixedly communicated with each of the two end cylinders (23), and the spiral air pipe (28) is spirally sleeved outside the end cylinder (23) and the piston rod (24). The bottom end of the spiral air pipe (28) is fixedly communicated with the annular cavity plate (30), and a connecting spring (25) is fixed between the top of the piston rod (24) and the top end of the end cylinder (23).

5. The 3D imaging device for underground cavities according to claim 2, characterized in that: A pair of guide rods (20) are fixed at a position of the main body frame (1) close to the mounting plate (4), and an extended side rod (19) is sleeved on the guide rod (20). The end of the extended side rod (19) is fixed on the moving cross bar (13).

6. The 3D imaging device for underground cavities according to claim 5, characterized in that: A folded rack (18) is fixed on one side of each of the two extended side rods (19). A transmission shaft (17) is rotatably installed at one end of each side of the mounting plate (4) close to the bottom. A second transmission belt (15) is sleeved between the transmission shaft (17) and the torsion spring shaft (6). A transmission gear (16) adapted to the folded rack (18) is fixed on the transmission shaft (17).

7. The 3D imaging device for underground cavities according to claim 2, wherein: A driving motor (21) is fixed on one side of the main body frame (1), and the output shaft of the driving motor (21) is fixedly connected to one of the lead screws (12).

8. The 3D imaging device for underground cavities according to claim 2, characterized in that: Drive wheels (36) are fixed to the tops of the two lead screws (12), and a pair of side wheels (37) are installed at one end of the main body frame (1) near the top. A first drive belt (14) is sleeved over the two drive wheels (36) and the two side wheels (37).

9. A 3D imaging device for underground cavities according to any one of claims 1-8, characterized in that: A signal line (11) is fixed to the top of the guide rod (10). The signal line (11) is spiral, and the two ends of the signal line (11) are electrically connected to the detection head (34) and the processing terminal (22) respectively.

10. The 3D imaging device for underground cavities according to claim 1, characterized in that: Two side guard plates (9) are fixed between one side of the main body frame (1) and the mounting plate (4). A pair of transparent side plates (2) are fixed to the other three sides of the main body frame (1). The top cover (8) is connected to the top of the main body frame (1) by a hinge.

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