Underwater building surface crack detection device and method thereof

Abstract

The invention discloses an underwater building surface crack detection device and method, and belongs to the technical field of crack detection, the underwater building surface crack detection device comprises an underwater positioning assembly, an underwater main driving assembly, an underwater auxiliary driving assembly and a crack gas detection mechanism; the crack gas detection mechanism comprises a reference frame, a crack gas detection box facing the underwater building is elastically installed on the reference frame, a gas detection cavity and a gas storage cavity which are spaced from each other are formed in the crack gas detection box, a cylinder communicating with the gas detection cavity and the gas storage cavity at the same time is fixedly installed above the crack gas detection box, and the gas detection cavity communicates with the outside. A pressure sensor is fixedly installed in the gas detection cavity, and an alarm electrically connected with the pressure sensor is fixedly installed above the crack gas detection box. The underwater building surface crack detection device is small in size and is more flexible during underwater operation; and secondly, the surface of the underwater building can be checked in a large area during detection, and the working efficiency is very high.

Description

Technical Field

[0001] The present invention relates to the technical field of crack detection, in particular to a device and method for detecting cracks on the surface of an underwater building. Background Art

[0002] Underwater buildings refer to those structures that are partially or completely located below the water surface, such as bridges, submarine tunnels, underwater oil platform foundations, etc. Most of the important structures in such underwater buildings are composed of concrete components. During long-term use, due to the invasion of external factors such as wind and waves, corrosion, hydraulic scouring and temperature stress, cracks will occur in the buildings, which requires timely inspection of underwater buildings.

[0003] Among the existing patent documents, there is a patent with publication number CN 112061304 A and the name of “An underwater building crack detection device”. This patent is used as a hull inspection and repair. Due to the large size of the hull, there are many inconveniences when driving or operating the hull underwater, and its flexibility in application is relatively poor. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a device and method for detecting cracks on the surface of an underwater building. The device for detecting cracks on the surface of an underwater building is small in size and more flexible when operating underwater. Secondly, it can conduct a large-area inspection of the surface of the underwater building during detection, and its working efficiency is very high.

[0005] To solve the above technical problems, the technical solution of the present invention is achieved as follows:

[0006] A device for detecting cracks on the surface of an underwater building comprises four groups of underwater positioning components, which are clamped and fixed on the side of the underwater building; each of the upper and lower groups of underwater positioning components are respectively fixedly installed with an underwater main drive component and an underwater auxiliary drive component; a crack gas detection mechanism is fixedly installed between the underwater main drive component and the underwater auxiliary drive component; the crack gas detection mechanism comprises a reference frame, the reference frame is elastically installed with a crack gas detection box facing the underwater building, the crack gas detection box is provided with a gas detection cavity and a gas storage cavity spaced from each other, and a gas cylinder connected to the gas detection cavity and the gas storage cavity is fixedly installed above the crack gas detection box, and the gas detection cavity is connected to the gas detection cavity and the gas storage cavity. The gas detection chamber is connected to the outside world, and can be sealed against the surface of the underwater building; a pressure sensor is fixedly installed in the gas detection chamber, and an alarm electrically connected to the pressure sensor is fixedly installed above the crack gas detection box, and the alarm is equipped with multiple alarm lights of different colors flashing alternately; an air injection nozzle is provided on the air storage chamber, and a one-way air injection valve assembly is installed at the location of the air injection nozzle; the one-way air injection valve assembly includes a valve core installed in the air injection nozzle, and both ends of the valve core are slidably installed on a guide shaft two fixed in the air storage chamber, and a spring two is mounted on the guide shaft for pushing the valve core to move, and the valve core can completely block the air injection nozzle under the elastic action of the spring two.

[0007] By adopting the above scheme, the underwater building surface crack detection device is small in size. When operating underwater, the gas in the air storage chamber is pumped into the gas detection chamber through the cylinder. At this time, the pressure in the gas detection chamber rises. If the pressure sensor detects a decrease in air pressure after a period of time, it indicates that the air pressure is leaking from the crack, which can prove that there is a crack here. Therefore, it will be more flexible in application; secondly, during detection, the movement of the crack gas detection mechanism can be realized through the underwater main drive component and the underwater auxiliary drive component, so that it can conduct a large-area inspection of the surface of the underwater building, and its working efficiency is very high.

[0008] As a preferred implementation of a device for detecting cracks on the surface of an underwater building, the two ends of a crack gas detection box are respectively slidably mounted on a guide shaft 1 fixed on the two ends of a reference frame, and the guide shaft 1 is sleeved with a spring 1 for pushing the crack gas detection box to move toward the underwater building; a sealing ring is clamped around the gas detection cavity, and the crack gas detection box can firmly press the sealing ring against the surface of the underwater building under the elastic push of the spring 1, so that the gas detection cavity can be fully sealed.

[0009] The above scheme is adopted, in order to realize the elastic propulsion of the crack gas detection box, it uses multiple sets of springs to push the crack gas detection box to the underwater building, so that the sealing ring is firmly pressed against the surface of the underwater building, thereby ensuring that the gas detection cavity has better sealing during detection.

[0010] As a preferred implementation of an underwater building surface crack detection device, the gas storage chamber is filled with an inert gas, such as nitrogen, whose pressure is higher than the external atmospheric pressure.

[0011] By adopting the above scheme, in order to reduce the dissolution of gas in the gas storage chamber into water, an inert gas with more stable chemical properties is used for gas intake detection, which will have a higher accuracy during detection.

[0012] As a preferred implementation of an underwater building surface crack detection device, a handle is provided in the valve core for sealing and rotating, a self-locking rod located in the air storage chamber is fixed at the end of the handle, a slot is provided at the rod head of the self-locking rod, and two bayonet pins for use with the slot are fixed in the air storage chamber; when the self-locking rod is rotated so that the slot is engaged with the bayonet pin, the lock core is self-locked.

[0013] By adopting the above scheme, in order to further improve the stability of the lock core, when air is injected, the lock core is pushed, and the spring 2 is compressed. At this time, the valve core no longer blocks the air injection nozzle, and the air injection can be completed; when the air injection is completed, by rotating the handle, when the self-locking rod is rotated so that the slot is engaged with the pin, the lock core is self-locked, thereby ensuring the reliability of the lock core.

[0014] As a preferred embodiment of an underwater building surface crack detection device, an underwater positioning assembly includes a positioning frame, a clamp seat 1 is fixed at one end of the positioning frame, a screw is rotatably installed at the end of the positioning frame away from the clamp seat 1, and a clamp seat 2 which is in the same straight line as the clamp seat 1 is fixed at the end of the screw; wherein, a plurality of anti-slip grooves are provided on the opposing surfaces of the clamp seat 1 and the clamp seat 2.

[0015] By adopting the above scheme, in order to achieve the clamping and fixing of the underwater positioning component on the side of the underwater building, by rotating the screw, the underwater positioning component can be firmly fixed to the side of the underwater building under the joint clamping of the clamp seat 1 and the clamp seat 2.

[0016] As a preferred embodiment of a surface crack detection device for underwater buildings, the underwater main drive assembly includes a stand 1 fixed on a positioning frame, a screw with a surface thread is rotatably installed on the stand 1, a waterproof motor for driving the screw to rotate is fixedly installed at the end of the stand 1, and a slide 1 for moving along the axial direction of the screw is mounted on the screw; the underwater auxiliary drive assembly includes a stand 2 fixed on the positioning frame, a slide rod with a smooth surface is rotatably installed on the stand 2, and a slide rod is mounted on the slide rod for moving along the axial direction of the slide rod; wherein the slide 1 and the slide 2 are respectively plugged and fixed to the two ends of the reference frame by pins.

[0017] By adopting the above scheme, in order to realize the large-range movement of the crack gas detection mechanism, the waterproof motor in the underwater main drive assembly can drive the screw to rotate. Under the threaded transmission, the slide one can move along the axial direction of the screw. At this time, the slide two moves synchronously with the slide one, and finally drives the reference frame to move.

[0018] A method for detecting cracks on the surface of an underwater building, the method for detecting cracks on the surface of an underwater building adopts the underwater building surface crack detection device for detection, and the specific operation steps are as follows:

[0019] S1. First, four sets of underwater positioning components are installed and fixed. During installation, by rotating the screw, the underwater positioning components can be firmly fixed to the side of the underwater building under the joint clamping of the clamp seat 1 and the clamp seat 2, and the distance between the upper and lower sets of underwater positioning components is exactly equal to the length of the underwater main drive component and the underwater auxiliary drive component.

[0020] S2, respectively fix the underwater main drive assembly and the underwater auxiliary drive assembly on each of the two upper and lower sets of underwater positioning assemblies, and then simultaneously insert the crack gas detection mechanism on the underwater main drive assembly and the underwater auxiliary drive assembly through the pin shaft to complete the installation of the device;

[0021] S3. During the inspection, check the state of the crack gas detection box; if the crack gas detection box is pushed toward the underwater building under the elastic push of spring 1, so that the sealing ring is firmly in contact with the surface of the underwater building, then the gas detection chamber is in a fully sealed state;

[0022] S4. Start the cylinder and draw the gas in the gas storage chamber into the gas detection chamber through the cylinder. At this time, the pressure in the gas detection chamber rises. If the pressure sensor detects a decrease in air pressure after a period of time, it indicates that the air pressure leaks from the crack, which proves that there is a crack here; otherwise, it proves that there is no crack here.

[0023] After adopting the above technical solution, the beneficial effects of the present invention are:

[0024] 1. The underwater building surface crack detection device is small in size. When operating underwater, the gas in the gas storage chamber is pumped into the gas detection chamber through the cylinder. At this time, the pressure in the gas detection chamber rises. If the pressure sensor detects a decrease in air pressure after a period of time, it indicates that the air pressure leaks from the crack, which can prove that there is a crack here. Therefore, it is more flexible in application; secondly, during detection, the underwater main drive component and the underwater auxiliary drive component can realize the movement of the crack gas detection mechanism, so that it can conduct a large-area inspection of the surface of the underwater building, and its working efficiency is very high;

[0025] 2. In order to realize the elastic push of the crack gas detection box, multiple sets of springs are used to push the crack gas detection box to the underwater building, so that the sealing ring is firmly pressed against the surface of the underwater building, so as to ensure that the gas detection cavity has better sealing during detection;

[0026] 3. In order to reduce the dissolution of gas in the gas storage cavity into water, the inert gas with more stable chemical properties is used for gas inlet detection, which will have higher accuracy during detection;

[0027] 4. In order to further improve the stability of the lock core, when air is injected, the lock core is pushed, and the second spring is compressed. At this time, the valve core no longer blocks the air injection nozzle, and the air injection can be completed. When the air injection is completed, the handle is rotated, and when the self-locking rod is rotated so that the card slot is connected to the card pin, the lock core is self-locked, thereby ensuring the reliability of the lock core;

[0028] 5. In order to realize the clamping and fixing of the underwater positioning component on the side of the underwater building, by rotating the screw, the underwater positioning component can be firmly fixed to the side of the underwater building under the joint clamping of the clamp seat 1 and the clamp seat 2;

[0029] 6. In order to realize the large-range movement of the crack gas detection mechanism, the waterproof motor in the underwater main drive assembly can drive the screw to rotate. Under the thread transmission, the slide seat 1 can move along the axial direction of the screw. At this time, the slide seat 2 moves synchronously with the slide seat 1, and finally drives the reference frame to move. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0031] Figure 1 The three-dimensional structure installed on the underwater building of the present invention Figure 1 ;

[0032] Figure 2 The three-dimensional structure installed on the underwater building of the present invention Figure 2 ;

[0033] Figure 3 It is a three-dimensional structural diagram of the present invention;

[0034] Figure 4 for Figure 3 Three-dimensional structure of the medium crack gas detection mechanism Figure 1 ;

[0035] Figure 5 for Figure 3 Three-dimensional structure of the medium crack gas detection mechanism Figure 2 ;

[0036] Figure 6 for Figure 4 The three-dimensional structure diagram of the interior;

[0037] Figure 7 for Figure 6 Three-dimensional structure of the one-way gas injection valve assembly Figure 1 ;

[0038] Figure 8 for Figure 6 Three-dimensional structure of the one-way gas injection valve assembly Figure 2 ;

[0039] Fig. 9 for Figure 3 Three-dimensional structure of underwater positioning components Figure 1 ;

[0040] Fig.10 for Figure 3 Three-dimensional structure of underwater positioning components Figure 2 ;

[0041] Fig.11 for Figure 3 A three-dimensional structural diagram of the underwater main drive assembly;

[0042] Fig.12 for Figure 3 A three-dimensional structural diagram of the underwater auxiliary drive assembly;

[0043] Markings in the figure: 1- underwater positioning assembly; 101- positioning frame; 102- clamp seat 1; 103- screw rod; 104- clamp seat 2; 2- underwater building; 3- underwater main drive assembly; 301- bench 1; 302- screw rod; 303- waterproof motor; 304- slide seat 1; 4- underwater auxiliary drive assembly; 401- bench 2; 402- slide rod; 403- slide seat 2; 5- crack gas detection mechanism; 501- reference frame; 502- crack gas detection box; 503-gas inspection chamber; 504-gas storage chamber; 505-cylinder; 506-pressure sensor; 507-alarm; 508-alarm light; 509-guide shaft one; 510-spring one; 511-sealing ring; 512-latch; 6-gas injection nozzle; 7-one-way gas injection valve assembly; 701-valve core; 702-guide shaft two; 703-spring two; 704-handle; 705-self-locking rod; 706-slot; 707-pin; 8-crack. DETAILED DESCRIPTION

[0044] 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.

[0045] like Figures 1 to 8As shown, a device for detecting cracks on the surface of an underwater building comprises four groups of underwater positioning components 1, which are clamped and fixed on the side of an underwater building 2; each of the upper and lower groups of underwater positioning components 1 are respectively fixedly installed with an underwater main drive component 3 and an underwater auxiliary drive component 4; a crack 8 gas detection mechanism 5 is fixedly installed between the underwater main drive component 3 and the underwater auxiliary drive component 4; the crack 8 gas detection mechanism 5 comprises a reference frame 501, the reference frame 501 is elastically installed with a crack 8 gas detection box 502 facing the underwater building 2, the crack 8 gas detection box 502 is provided with a gas detection cavity 503 and a gas storage cavity 504 spaced from each other, and a cylinder 505 which is connected to the gas detection cavity 503 and the gas storage cavity 504 at the same time is fixedly installed above the crack 8 gas detection box 502, and the gas detection cavity 503 is connected to the outside The gas inspection chamber 503 can be sealed against the surface of the underwater building 2; a pressure sensor 506 is fixedly installed in the gas inspection chamber 503, and an alarm 507 electrically connected to the pressure sensor 506 is fixedly installed above the crack 8 gas inspection box 502, and the alarm 507 is equipped with multiple alarm lights 508 of different colors flashing alternately; an air injection nozzle 6 is provided on the air storage chamber 504, and a one-way air injection valve assembly 7 is installed at the location of the air injection nozzle 6; the one-way air injection valve assembly 7 includes a valve core 701 installed in the air injection nozzle 6, and both ends of the valve core 701 are slidably installed on a guide shaft 702 fixed in the air storage chamber 504, and a spring 703 for pushing the valve core 701 to move is mounted on the guide shaft, and the valve core 701 can completely block the air injection nozzle 6 under the elastic action of the spring 703. The underwater building surface crack detection device is small in size. When operating underwater, the gas in the air storage chamber 504 is pumped into the air detection chamber 503 through the cylinder 505. At this time, the pressure in the air detection chamber 503 rises. If the pressure sensor 506 detects a decrease in air pressure after a period of time, it indicates that the air pressure is leaking from the crack 8, which can prove that the crack 8 exists here. Therefore, it will be more flexible in application; secondly, during detection, the movement of the crack 8 air detection mechanism 5 can be realized through the underwater main drive component 3 and the underwater auxiliary drive component 4, so that it can conduct a large-area inspection of the surface of the underwater building 2, and its working efficiency is very high.

[0046] like Figures 5 and 6As shown, the two ends of the crack 8 gas detection box 502 are respectively slidably mounted on the guide shaft 1 509 fixed at the two ends of the reference frame 501, and the guide shaft 1 509 is sleeved with a spring 1 510 for pushing the crack 8 gas detection box 502 to move to the underwater building 2; the surrounding limit clamp of the gas detection cavity 503 is connected with a sealing ring 511, and the crack 8 gas detection box 502 can firmly press the sealing ring 511 against the surface of the underwater building 2 under the elastic push of the spring 1 510, and the gas detection cavity 503 can be fully sealed. In order to realize the elastic push of the crack 8 gas detection box 502, it uses multiple sets of springs 1 510 to push the crack 8 gas detection box 502 to the underwater building 2, so that the sealing ring 511 is firmly pressed against the surface of the underwater building 2, so as to ensure that the gas detection cavity 503 has better sealing during detection.

[0047] like Figure 6 As shown, the gas storage chamber 504 is filled with an inert gas with a pressure higher than the external atmospheric pressure, such as nitrogen, etc. In order to reduce the gas in the gas storage chamber 504 from dissolving in water, an inert gas with more stable chemical properties is used for gas inlet detection, which will have a higher accuracy during detection.

[0048] like Figures 7 and 8 As shown, a rotary handle 704 is sealed and rotated inside the valve core 701, and a self-locking rod 705 located in the gas storage chamber 504 is fixed at the end of the rotary handle 704. A slot 706 is provided at the rod head of the self-locking rod 705, and two bayonet pins 707 used in conjunction with the slot 706 are fixed inside the gas storage chamber 504; when the self-locking rod 705 is rotated so that the slot 706 is engaged with the bayonet pin 707, the lock core is self-locked. In order to further improve the stability of the lock core, when gas is injected, the lock core is pushed, and the spring 2 703 is compressed. At this time, the valve core 701 no longer blocks the gas injection nozzle 6, and gas injection can be completed at this time; when gas injection is completed, the rotary handle 704 is rotated, and when the self-locking rod 705 is rotated so that the slot 706 is engaged with the bayonet pin 707, the lock core is self-locked, thereby ensuring the reliability of the lock core.

[0049] like Figures 9 and 10 As shown, the underwater positioning assembly 1 includes a positioning frame 101, one end of which is fixed with a clamp seat 102, and the end of the positioning frame 101 away from the clamp seat 102 is rotatably mounted with a screw rod 103, and the end of the screw rod 103 is fixed with a clamp seat 2 104 which is in the same straight line as the clamp seat 102; wherein, the opposing surfaces of the clamp seat 102 and the clamp seat 2 104 are provided with a plurality of anti-skid grooves. In order to achieve the clamping and fixing of the underwater positioning assembly 1 on the side of the underwater building 2, by rotating the screw rod 103, the underwater positioning assembly 1 can be firmly fixed to the side of the underwater building 2 under the joint clamping of the clamp seat 102 and the clamp seat 2 104.

[0050] like Figure 11 to Figure 12As shown, the underwater main driving component 3 includes a stand 301 fixed on the positioning frame 101, a screw rod 302 with a surface thread is rotatably installed on the stand 301, a waterproof motor 303 for driving the screw rod 302 to rotate is fixedly installed at the end of the stand 301, and a slide 304 is mounted on the screw rod 302 for axial movement along the screw rod 302; the underwater auxiliary driving component 4 includes a stand 401 fixed on the positioning frame 101, a slide rod 402 with a smooth surface is rotatably installed on the stand 401, and a slide 403 is mounted on the slide rod 402 for axial movement along the slide rod 402; wherein, the slide 304 and the slide 403 are respectively plugged and fixed to the two ends of the reference frame 501 by pins 512. In order to realize a large range of movement of the crack 8 gas detection mechanism 5, the waterproof motor 303 in the underwater main drive assembly 3 can drive the screw 302 to rotate. Under the threaded transmission, the slide 1 304 can move axially along the screw 103. At this time, the slide 2 403 moves synchronously with the slide 1 304, and finally drives the reference frame 501 to move.

[0051] A method for detecting cracks on the surface of an underwater building, the method for detecting cracks on the surface of an underwater building adopts the underwater building surface crack detection device for detection, and the specific operation steps are as follows:

[0052] S1. First, four groups of underwater positioning components 1 are installed and fixed. During installation, by rotating the screw 103, the underwater positioning components 1 can be firmly fixed to the side of the underwater building 2 under the joint clamping of the clamp seat 1 102 and the clamp seat 2 104, and the distance between the upper and lower groups of underwater positioning components 1 is exactly equal to the length of the underwater main drive component 3 and the underwater auxiliary drive component 4.

[0053] S2, the underwater main drive assembly 3 and the underwater auxiliary drive assembly 4 are fixedly installed on each upper and lower set of underwater positioning assemblies 1, and then the crack 8 gas detection mechanism 5 is simultaneously inserted into the underwater main drive assembly 3 and the underwater auxiliary drive assembly 4 through the pin shaft, and the installation of the device can be completed. Figure 1 to Figure 2 As shown;

[0054] S3. During the inspection, check the state of the crack 8 gas detection box 502; if the crack 8 gas detection box 502 is pushed toward the underwater building 2 by the elastic force of the spring 1 510, so that the sealing ring 511 is firmly in contact with the surface of the underwater building 2, then the gas detection chamber 503 is in a fully sealed state;

[0055] S4, start the cylinder 505, and draw the gas in the gas storage chamber 504 into the gas detection chamber 503 through the cylinder 505. At this time, the pressure in the gas detection chamber 503 rises. If the pressure sensor 506 detects a decrease in air pressure after a period of time, it indicates that the air pressure leaks from the crack 8, which proves that the crack 8 exists here; otherwise, it proves that there is no crack 8 here.

[0056] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A device for detecting cracks on the surface of an underwater building, comprising four groups of underwater positioning components, which are clamped and fixed on the side of the underwater building; each upper and lower groups of underwater positioning components are respectively fixedly installed with an underwater main drive component and an underwater auxiliary drive component; a crack gas detection mechanism is commonly fixedly installed between the underwater main drive component and the underwater auxiliary drive component; Features: The crack gas detection mechanism comprises a reference frame, on which a crack gas detection box facing the underwater building is elastically mounted, a gas detection chamber and a gas storage chamber spaced apart from each other are provided in the crack gas detection box, a gas cylinder connected to both the gas detection chamber and the gas storage chamber is fixedly mounted above the crack gas detection box, the gas detection chamber is connected to the outside, and the gas detection chamber can be sealed against the surface of the underwater building; a pressure sensor is fixedly mounted in the gas detection chamber, an alarm electrically connected to the pressure sensor is fixedly mounted above the crack gas detection box, and a plurality of alarm lights flashing alternately in different colors are mounted on the alarm; The air storage chamber is provided with an injection nozzle, and a one-way injection valve assembly is installed at the location of the injection nozzle; the one-way injection valve assembly includes a valve core installed in the injection nozzle, and both ends of the valve core are slidably installed on a guide shaft 2 fixed in the air storage chamber, and a spring 2 is mounted on the guide shaft to push the valve core to move, and the valve core can completely block the injection nozzle under the elastic action of the spring 2.

2. The underwater building surface crack detection device according to claim 1, Features: The two ends of the crack gas detection box are respectively slidably mounted on a guide shaft 1 fixed on the two ends of the reference frame, and a spring 1 is sleeved on the guide shaft 1 to push the crack gas detection box to move toward the location of the underwater building.

3. The underwater building surface crack detection device according to claim 2, Features: The gas detection cavity is provided with a sealing ring at a limit position clamp around it. The crack gas detection box can firmly press the sealing ring against the surface of the underwater building under the elastic push of the spring 1, so that the gas detection cavity can be fully sealed.

4. The underwater building surface crack detection device according to claim 3, Features: The gas storage cavity is filled with an inert gas whose pressure is higher than the external atmospheric pressure.

5. The underwater building surface crack detection device according to claim 4, Features: A handle is provided in the valve core for sealing and rotation, a self-locking rod located in the air storage chamber is fixed to the end of the handle, a slot is provided at the rod head of the self-locking rod, and two bayonet pins for use with the slot are fixed in the air storage chamber; when the self-locking rod is rotated so that the slot is engaged with the bayonet pin, the lock core is self-locked.

6. The underwater building surface crack detection device according to claim 5, Features: The underwater positioning assembly includes a positioning frame, one end of which is fixed with a clamp seat 1, the end of the positioning frame away from the clamp seat 1 is rotatably mounted with a screw, and the end of the screw is fixed with a clamp seat 2 which is in the same straight line as the clamp seat 1.

7. The underwater building surface crack detection device according to claim 6, Features: A plurality of anti-slip grooves are arranged on the opposite surfaces of the clamp seat 1 and the clamp seat 2.

8. The underwater building surface crack detection device according to claim 7, Features: The underwater main drive assembly includes a stand 1 fixed on the positioning frame, a screw with a surface thread is rotatably mounted on the stand 1, a waterproof motor for driving the screw to rotate is fixedly mounted on the end of the stand 1, and a slide seat 1 is mounted on the screw to move along the axial direction of the screw; The underwater auxiliary driving assembly comprises a second platform fixed on the positioning frame, a sliding rod with a smooth surface is rotatably mounted on the second platform, and a sliding seat second which moves along the axial direction of the sliding rod is mounted on the sliding rod.

9. The underwater building surface crack detection device according to claim 8, Features: The first slide and the second slide are respectively plugged and fixed with two ends of the reference frame through latches.

10. A method for detecting cracks on the surface of an underwater building. Features: The underwater building surface crack detection method uses the underwater building surface crack detection device according to claim 9 for detection, and its specific operation steps are as follows: S1. First, four sets of underwater positioning components are installed and fixed. During installation, by rotating the screw, the underwater positioning components can be firmly fixed to the side of the underwater building under the joint clamping of the clamp seat 1 and the clamp seat 2, and the distance between the upper and lower sets of underwater positioning components is exactly equal to the length of the underwater main drive component and the underwater auxiliary drive component. S2, respectively fix the underwater main drive assembly and the underwater auxiliary drive assembly on each of the two upper and lower sets of underwater positioning assemblies, and then simultaneously insert the crack gas detection mechanism on the underwater main drive assembly and the underwater auxiliary drive assembly through the pin shaft to complete the installation of the device; S3. During the inspection, check the state of the crack gas detection box; if the crack gas detection box is pushed toward the underwater building under the elastic push of spring 1, so that the sealing ring is firmly in contact with the surface of the underwater building, then the gas detection chamber is in a fully sealed state; S4, start the cylinder, and draw the gas in the gas storage chamber into the gas detection chamber through the cylinder. At this time, the pressure in the gas detection chamber rises. If the pressure sensor detects that the air pressure decreases after a period of time, it indicates that the air pressure leaks from the crack, which can prove that there is a crack here; Otherwise, it proves that there is no crack here.

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