An unshielded offshore bridge bottom intelligent riprapping device and method

Abstract

The application discloses a kind of unshielded outer sea bridge bottom intelligent riprapping devices, belong to building construction technical field, including horizontal rail, horizontal rail is fixed on bridge deck, hoisting beam is slidably connected in the lower portion of horizontal rail, hoisting beam moves along horizontal rail, hoisting beam is fixedly connected with longitudinal rail, electric hoist is installed on longitudinal rail, electric hoist moves along longitudinal rail, and hook is provided on electric hoist, to throw stone to bridge bottom by hook.The application further discloses a kind of unshielded outer sea bridge bottom intelligent riprapping method.The application can be safely and firmly installed on existing bridge deck structure, resist outer sea wind vibration and sway, while having sufficient flexibility, can cover the area of bridge bottom needing to throw stone, and can realize the automatic lifting, translation and drop of stone, complete accurate throwing.

Description

Technical Field

[0001] This invention belongs to the field of building construction technology, and in particular relates to an intelligent rock-throwing device and method for unprotected offshore bridge bottoms. Background Technology

[0002] Offshore bridges, especially those in unprotected sea areas far from the coastline, are subject to long-term erosion and corrosion from waves, which can easily lead to foundation erosion and structural damage, severely affecting the overall stability and durability of the bridge. To address this, filling the top and surrounding areas of the seabed piles with riprap, gravel, or other protective materials to form a protective abutment or erosion layer is a common and effective protective measure.

[0003] However, traditional rock-dropping operations heavily rely on large rock-dropping vessels. In the open, unprotected sea, with complex wind, wave, and current conditions, precise vessel positioning and stable anchoring are inherently difficult, the construction window is short, and safety risks are high. Especially for the areas beneath existing bridges, vessels, due to the limitations of their large cranes' operating radius and draft, cannot easily enter the confined space under the bridge for close-range, precise rock-dropping, making collisions with the pile foundations highly likely. Even using smaller vessels presents problems such as low efficiency, poor uniformity of rock-dropping, and high costs, making pile foundation protection difficult to implement or ineffective for many existing offshore bridges.

[0004] Therefore, there is an urgent need to design an intelligent rock-throwing device and method for unprotected offshore bridge foundations to solve the problem mentioned above of the difficulty in implementing or the poor effectiveness of pile foundation protection for offshore bridges. Summary of the Invention

[0005] To address the technical problem mentioned in the background art that the protection of the pile foundations of offshore bridges is difficult to implement or has poor effect, an unprotected intelligent rock-throwing device and method for the bottom of offshore bridges is provided to solve the above problems.

[0006] To achieve the above objectives, the specific technical solution of the unprotected offshore bridge-bottom intelligent rock-throwing device and method of the present invention is as follows:

[0007] An unprotected intelligent rock-throwing device for the underside of an offshore bridge includes a transverse track, which is fixed to the bridge deck. A lifting beam is slidably connected below the transverse track and moves along the transverse track. A longitudinal track is fixedly connected to the lifting beam, and an electric hoist is installed on the longitudinal track. The electric hoist moves along the longitudinal track and is equipped with a hook, thereby throwing rocks under the bridge through the hook.

[0008] Furthermore, multiple clamping devices are fixedly connected to the transverse track. The transverse track is secured to the bridge deck through the clamping devices. The clamping devices include an upper clamping block and a lower clamping block. The upper clamping block has a first screw hole, and the lower clamping block has a second screw hole. A connecting screw is screwed between the first screw hole and the second screw hole. The lower clamping block is fixedly connected to the transverse track.

[0009] Furthermore, the connecting screw includes a first thread and a second thread, the first thread and the second thread are opposite threads, the first thread is adapted to the first threaded hole, and the second thread is adapted to the second threaded hole. Rotating the connecting screw causes the upper clamping block and the lower clamping block to clamp the bridge surface.

[0010] Furthermore, a wheel guard recess is provided on the upper clamping block, and a buffer layer is provided inside the wheel guard recess. The wheel guard recess abuts against the wheel guard on the bridge deck through the buffer layer.

[0011] Furthermore, a groove is provided on the bottom surface of the lower clamping block, and a slider is slidably connected in the groove. A base is connected to the bottom of the connecting screw, and the base can rotate relative to the connecting screw. A first diagonal brace is hinged to the slider, and the end of the first diagonal brace away from the slider is hinged to the base. A top support is connected to the top of the connecting screw, and the top support can rotate relative to the connecting screw. A fixed seat is provided on the upper clamping block, and the fixed seat and the top support are fixedly connected by a second diagonal brace. A hexagonal nut is fixedly connected to the connecting screw. Rotating the hexagonal nut causes the connecting screw to rotate.

[0012] Furthermore, the electric hoist includes a moving mechanism and a lifting mechanism. The moving mechanism is fixedly connected to the lifting mechanism. The moving mechanism is equipped with a traveling wheel and a first motor. The traveling wheel is rotatably connected to the longitudinal track. The output end of the first motor is connected to the traveling wheel to drive the traveling wheel to move on the longitudinal track, thereby driving the lifting mechanism to move on the longitudinal track. The lifting mechanism is equipped with a second motor and a wire rope drum. The hook is fixedly connected to the wire rope on the wire rope drum. The output end of the second motor is fixedly connected to the wire rope drum. The second motor drives the wire rope drum to rotate forward or backward, thereby driving the hook to rise or fall.

[0013] Furthermore, the longitudinal track includes a straight track and an ascending track, which are fixedly connected, and the top of the ascending track is greater than or equal to the bridge deck height.

[0014] The ascending track consists of an ascending section and a top section. The ascending section and the top section are connected by an arc to form the first arc track section. The ascending section and the straight track are connected by an arc to form the second arc track section.

[0015] Furthermore, the traveling wheel includes a gear wheel and a circular wheel. The gear wheel is fixedly connected to the circular wheel and is located outside the circular wheel. The rising rail is provided with a rack protrusion that matches the gear wheel. The traveling wheel moves on the straight rail via the circular wheel, and the traveling wheel moves on the rising rail via the combined movement of the circular wheel and the gear wheel.

[0016] Another object of the present invention is to provide a method for intelligent rock-throwing under an unprotected offshore bridge, using the aforementioned intelligent rock-throwing device for unprotected offshore bridges, comprising the following steps:

[0017] S1. Fill sandbags or gravel into special net bags and transport them to the designated area on the bridge surface by transport vehicles;

[0018] S2. The bridge crane lifts the net bag to the edge of the bridge deck, and the electric hoist moves it to the top of the rising rail.

[0019] S3. The electric hoist is attached to the net bag. The crane moves the net bag to the connection position between the straight rail and the rising rail. The electric hoist hook remains attached but does not bear any load.

[0020] S4. The electric hoist gradually applies force until it fully supports the net bag, then the crane disconnects.

[0021] S5. Based on the target rock-throwing coordinates, adjust the lifting beam and electric hoist using a multi-modal positioning system to lower the net bag to 1.0 m directly above the rock-throwing point.

[0022] S6. The intelligent sensing unit of the multimodal positioning system detects the stone-throwing position in real time. If the position matches, the stone-throwing is executed; otherwise, the stone-throwing is dynamically adjusted.

[0023] Furthermore, the multimodal positioning system includes:

[0024] The Gray busbar positioning system, laid on the transverse and longitudinal tracks, is used to detect the planar coordinates of the hook;

[0025] A rotary encoder mounted on the first motor calculates the vertical coordinates of the net bag based on the length of the wire rope being extended and retracted.

[0026] The hook is equipped with a motion sensing unit, including a sonar ranging module and a visual recognition module;

[0027] After the target coordinates of the rock-throwing are input, the multimodal positioning system automatically plans the path, controls the lifting beam and electric hoist to move to the target position, and dynamically corrects the spatial pose of the net bag through the data transmitted by the sonar ranging module and the visual recognition module. The visual recognition module compares the real-time image with the preset rock-throwing area. If the matching degree exceeds the threshold, the rock-throwing is triggered; otherwise, the deviation is reported and the positioning is re-established.

[0028] The visual recognition module uses deep learning algorithms to identify the boundary of the area to be thrown through a pre-trained rock-throwing area segmentation model, and combines sonar data and visual recognition results to construct a three-dimensional rock-throwing decision space, thereby achieving adaptive rock-throwing positioning under complex sea conditions.

[0029] The unprotected intelligent rock-throwing device and method under the offshore bridge of the present invention have the following advantages:

[0030] This invention can be safely and securely installed on existing bridge structures, resisting offshore wind vibrations and swaying, while also possessing sufficient flexibility to cover the area under the bridge where stones need to be thrown, and can realize the automatic lifting, horizontal movement and lowering of stones to complete precise throwing.

[0031] This invention constructs a three-dimensional stone-throwing decision space. The multimodal positioning system can combine multi-source information to make the optimal stone-throwing judgment, reducing human error. At the same time, through real-time data feedback and closed-loop control, the system can dynamically compensate for the impact of environmental changes. After the operator inputs the coordinates, the entire process from target identification, path planning, precise docking to stone-throwing triggering can be automated, achieving high-precision stone-throwing operations and avoiding environmental impact problems. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the unprotected offshore bridge bottom intelligent rock-throwing device of the present invention;

[0033] Figure 2 This is a front view of the unprotected offshore bridge-bottom intelligent rock-throwing device of the present invention;

[0034] Figure 3 This is a schematic diagram of the snap-fit ​​device structure of the present invention;

[0035] Figure 4 This is a schematic diagram of the bottom structure of the snap-fit ​​device of the present invention;

[0036] Figure 5 This is a schematic diagram of the electric hoist structure of the present invention;

[0037] Figure 6 This is a schematic diagram of the walking wheel structure of the present invention;

[0038] Figure 7 for Figure 1 Enlarged view of part A in the image;

[0039] Figure 8 This is a flowchart of the unprotected offshore bridge bottom intelligent rock-throwing method of the present invention.

[0040] Explanation of markings in the diagram: 1. Transverse track; 2. Lifting beam; 3. Longitudinal track; 31. Straight track; 32. Ascending track; 321. Ascending section; 322. Top section; 323. First arc-shaped track section; 324. Second arc-shaped track section; 325. Rack and pinion protrusion; 4. Electric hoist; 41. Hook; 42. Moving mechanism; 421. Traveling wheel; 4211. Gear wheel; 4212. Circular wheel; 422. First motor; 43. Lifting mechanism; 431 432. Second motor; 5. Wire rope drum; 6. Clamping device; 501. Upper clamping block; 502. Lower clamping block; 503. Connecting screw; 504. Guard wheel notch; 505. Slide groove; 506. Sliding block; 507. Base support; 508. First diagonal brace; 509. Fixed seat; 510. Top support; 511. Second diagonal brace; 512. Hexagonal nut; 100. First screw hole; 200. Second screw hole; 300. First thread; 400. Second thread; 6. Bridge deck. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] Those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the claims, any of the claimed embodiments can be used in any combination.

[0043] The following is a reference to the appendix. Figure 1 To be continued Figure 8 This invention describes an unprotected intelligent rock-throwing device and method for the underside of an offshore bridge.

[0044] An unprotected intelligent rock-throwing device under a bridge in the open sea, such as Figure 1 and Figure 2As shown, the system includes a transverse track 1, which is fixed to the bridge deck 6. A lifting beam 2 is slidably connected below the transverse track 1 and moves along the transverse track 1. A longitudinal track 3 is fixedly connected to the lifting beam 2, and an electric hoist 4 is installed on the longitudinal track 3. The electric hoist 4 moves along the longitudinal track 3 and is equipped with a hook 41, which is used to throw stones from the bridge bottom. Specifically, the electric hoist 4 is driven to move in three dimensions by the transverse track 1 and the longitudinal track 3 fixed to the bridge deck 6, so as to accurately throw stones from the bridge bottom and avoid the problem of anchoring and positioning of ships. This enables the operation of throwing stones directly from the bridge deck 6 to the bridge bottom under unprotected open sea conditions. Optionally, the lifting beam 2 is equipped with a drive motor (not shown in the figure) and a drive wheel (not shown in the figure). The output end of the drive motor is connected to the drive wheel, which is rotatably connected to the transverse track 1. The drive motor drives the drive wheel to rotate, so that the lifting beam 2 moves on the transverse track 1.

[0045] As a preferred option, such as Figures 1-3 As shown, multiple clamping devices 5 are fixedly connected to the transverse track 1. The transverse track 1 is secured to the bridge deck 6 through the clamping devices 5. The clamping device 5 includes an upper clamping block 501 and a lower clamping block 502. The upper clamping block 501 has a first screw hole 100, and the lower clamping block 502 has a second screw hole 200. A connecting screw 503 is screwed between the first screw hole 100 and the second screw hole 200. The lower clamping block 502 is fixedly connected to the transverse track 1. Specifically, the clamping device 5 provides a stable installation foundation for the entire device, and also avoids drilling holes in the bridge deck 6, thus avoiding damage to the prestressed structure of the bridge.

[0046] Meanwhile, it is understood that the number of connecting screws 503 on the snap-fit ​​device 5 and the number of snap-fit ​​devices 5 on the transverse track 1 are calculated according to different load conditions. The number of snap-fit ​​devices 5 and connecting screws 503 in the embodiments of the present invention is only for the purpose of more clearly and intuitively illustrating the technical solution of the present invention.

[0047] Furthermore, such as Figure 3 As shown, the connecting screw 503 includes a first thread 300 and a second thread 400. The first thread 300 and the second thread 400 are reverse threads. The first thread 300 is adapted to the first threaded hole 100, and the second thread 400 is adapted to the second threaded hole 200. Rotating the connecting screw 503 causes the upper clamping block 501 and the lower clamping block 502 to clamp the bridge surface 6. Specifically, the first thread 300 is a left-hand thread, and the corresponding first threaded hole 100 is a left-hand threaded hole. The second thread 400 is a right-hand thread, and the corresponding second threaded hole 200 is a right-hand threaded hole. Rotating the connecting screw 503 causes the upper clamping block 501 and the lower clamping block 502 to move closer to each other and clamp the bridge surface 6.

[0048] Preferably, the upper clamping block 501 has a wheel guard recess 504, and a buffer layer is provided in the wheel guard recess 504. The wheel guard recess 504 abuts against the wheel guard of the bridge deck 6 through the buffer layer. Preferably, the buffer layer can be set as a rubber pad, so as to provide structural avoidance and protection for the wheel guard.

[0049] As a preferred option, such as Figure 3 and Figure 4 As shown, the bottom surface of the lower clamping block 502 has a sliding groove 505, and a slider 506 is slidably connected in the sliding groove 505. The bottom of the connecting screw 503 is connected to a base 507, which can rotate relative to the connecting screw 503. A first inclined brace 508 is hinged to the slider 506, and the end of the first inclined brace 508 away from the slider 506 is hinged to the base 507. A top support 510 is connected to the top of the connecting screw 503, which can rotate relative to the connecting screw 503. A fixed seat 509 is provided on the upper clamping block 501, and the fixed seat 509 and the top support 510 are connected. The second diagonal brace 511 is fixedly connected; a hexagonal nut 512 is fixedly connected to the connecting screw 503. Rotating the hexagonal nut 512 causes the connecting screw 503 to rotate. Specifically, during installation, the upper clamping block 501 is engaged with the top of the bridge deck 6 through the guard wheel recess 504 for rotational limitation. The operator rotates the connecting screw 503 through the hexagonal nut 512, causing the connecting screw 503 to drive the lower clamping block 502 upward until it clamps the bridge deck 6. Then, one end of the second diagonal brace 511 is hinged or fixedly connected to the top support 510. Figure 3 The second diagonal brace 511 is fixedly connected to the fixed base 509 via a hinged connection. This allows the second diagonal brace 511, the upper clamping block 501, and the portion of the connecting screw 503 extending beyond the top surface of the upper clamping block 501 to form the first stable triangular support structure. Furthermore, since the height of the connecting screw 503 is fixed, the angle between the connecting screw 503 and the first diagonal brace 508 is also fixed. This allows the first diagonal brace 508, the lower clamping block 502, and the portion of the connecting screw 503 extending beyond the bottom surface of the lower clamping block 502 to form the second stable triangular support structure. This allows the connecting screw 503 to achieve a further locking effect through the second diagonal brace 511 while maintaining its own thread self-locking, thus improving the safety of the structure. At the same time, the two triangular support structures ensure the stability and impact resistance of the overall structure, greatly improving the structural rigidity and reliability.

[0050] As a preferred option, such as Figure 5As shown, the electric hoist 4 includes a moving mechanism 42 and a lifting mechanism 43. The moving mechanism 42 and the lifting mechanism 43 are fixedly connected. The moving mechanism 42 is equipped with a traveling wheel 421 and a first motor 422. The traveling wheel 421 is rotatably connected to the longitudinal track 3. The output end of the first motor 422 is driven by the traveling wheel 421 to drive the traveling wheel 421 to move on the longitudinal track 3, thereby driving the lifting mechanism 43 to move on the longitudinal track 3. The lifting mechanism 43 is equipped with a second motor 431 and a wire rope drum 4. 32. The hook 41 is fixedly connected to the wire rope on the wire rope drum 432. The output end of the second motor 431 is fixedly connected to the wire rope drum 432. The second motor 431 drives the wire rope drum 432 to rotate in the forward or reverse direction, so as to drive the hook 41 to rise or fall. Specifically, the traveling wheel 421 travels on the longitudinal track 3 and cooperates with the lifting beam 2 to move on the transverse track 1 to achieve planar coverage of the stone throwing position. Then, the hook 41 is used to throw the stone, which ensures the stability and reliability of the movement and lifting process during the stone throwing process.

[0051] As a preferred option, such as Figure 2 , Figure 7 As shown, the longitudinal track 3 includes a straight track 31 and an ascending track 32, which are fixedly connected. The top of the ascending track 32 is greater than or equal to the height of the bridge deck 6. The ascending track 32 includes an ascending section 321 and a top section 322. The ascending section 321 and the top section 322 form a first arc-shaped track section 323 through an arc transition. The ascending section 321 and the straight track 31 form a second arc-shaped track section 324 through an arc transition. Specifically, the top of the ascending track 32 is greater than or equal to the height of the bridge deck 6, which facilitates personnel to hook the hook 41 of the electric hoist 4 on the bridge deck 6. At the same time, the arc-shaped track forms a buffer structure, making the longitudinal track 3 linear and smooth, reducing the pressure on the output power of the first motor 422, and enabling the electric hoist to move stably on the longitudinal track 3.

[0052] As a preferred option, such as Figure 6 and Figure 7 As shown, the traveling wheel 421 includes a gear wheel 4211 and a circular wheel 4212. The gear wheel 4211 and the circular wheel 4212 are fixedly connected. The gear wheel 4211 is located outside the circular wheel 4212. The rising rail 32 is provided with a rack protrusion 325 that matches the gear wheel 4211. The traveling wheel 421 moves on the straight rail 31 via the circular wheel 4212. The traveling wheel 421 moves on the rising rail 32 via the coordinated movement of the circular wheel 4212 and the gear wheel 4211. Specifically, on the straight rail 31, the circular wheel 4212 provides efficient and low-resistance movement. On the rising rail 32, the meshing of the gear and rack provides greater driving force and reliable anti-slip protection, effectively solving the problem of insufficient power and slippage that may occur when the electric hoist 4 is climbing a slope.

[0053] A method for intelligent rock dumping under an unprotected offshore bridge, such as Figure 8 As shown, it includes the following steps:

[0054] S1. Fill sandbags or gravel into special net bags and transport them to the designated area on the bridge surface using transport vehicles;

[0055] S2, the crane on bridge deck 6 lifts the net bag to the edge of bridge deck 6, and the electric hoist 4 moves to the top of the lifting rail 32;

[0056] S3. The electric hoist 4 hooks the net bag, and the crane moves the net bag to the connection position between the straight rail 31 and the rising rail 32. The hook 41 of the electric hoist 4 remains hooked but does not bear any force.

[0057] S4, the electric hoist 4 gradually applies force until it fully supports the net bag, then the crane disconnects;

[0058] S5. Based on the target rock-throwing coordinates, the lifting beam 2 and electric hoist 4 are adjusted using a multimodal positioning system to lower the net to a position 1.0 m directly above the rock-throwing point. The multimodal positioning system includes: a Gray line positioning system laid on the transverse track 1 and the longitudinal track 3 to detect the planar coordinates of the hook 41; a rotary encoder installed on the first motor 422 to calculate the vertical coordinates of the net based on the length of the wire rope; and a motion sensing unit installed on the hook 41, including a sonar ranging module and a visual recognition module.

[0059] S6. The intelligent sensing unit of the multimodal positioning system detects the position of the stone in real time. If the position matches, the stone is thrown. Otherwise, the stone is thrown after dynamic adjustment. After the target coordinates of the stone are input, the multimodal positioning system automatically plans the path and controls the lifting beam 2 and electric hoist 4 to move to the target position. The spatial pose of the net is dynamically corrected through the data transmitted by the sonar ranging module and the visual recognition module. The visual recognition module compares the real-time image with the preset stone throwing area. If the matching degree exceeds the threshold, the stone is thrown. Otherwise, the deviation is fed back and the positioning is re-established.

[0060] The visual recognition module uses deep learning algorithms to identify the boundary of the area to be thrown through a pre-trained rock-throwing area segmentation model, and combines sonar data and visual recognition results to construct a three-dimensional rock-throwing decision space to achieve adaptive rock-throwing positioning under complex sea conditions.

[0061] Specifically, the distance between the hook 41 and the target below (i.e., the top of the pile) is measured by the transmission and reception of sound waves. The visual recognition module captures images of the underwater environment through a camera and analyzes them through a deep learning algorithm to identify the target area, boundaries, and matching degree with a preset reference.

[0062] Deep learning algorithms include:

[0063] Pre-trained stone-throwing region segmentation model: The model is trained using a large number of labeled stone-throwing region images, such as semantic segmentation or instance segmentation models like U-Net and Mask R-CNN, which can identify the boundaries of the region to be thrown.

[0064] Image comparison: The image captured in real time by the camera is compared with a preset throwing area model or reference image. For example, the threshold is set to 95%. When the overlap between the visually recognized throwing area and the current net projection position reaches more than 95%, the image comparison is completed, confirming that the net has reached the target area.

[0065] Construction of a 3D boulder throwing decision space: A 3D decision space is constructed by combining distance and depth information provided by sonar ranging data and planar position and boundary information provided by the visual recognition module. In this space, the system evaluates the feasibility of throwing boulder at different locations, such as: whether the current net is within the preset boulder throwing area, and the deviation between the net and the target point. Based on the evaluation results in this 3D space, a boulder throwing decision is made.

[0066] Meanwhile, if the matching degree is insufficient or there is a large deviation, the multimodal positioning system will feed back the deviation information to the operator so that the operator can understand the underwater conditions, reposition, and perform path planning and precise positioning again.

[0067] This invention can be safely and securely installed on the existing bridge deck structure, resisting offshore wind vibration and swaying, while having sufficient flexibility to cover the area under the bridge where stones need to be thrown, and can realize the automatic lifting, horizontal movement and lowering of stones to complete precise throwing.

[0068] This invention constructs a three-dimensional stone-throwing decision space. The multimodal positioning system can combine multi-source information to make the optimal stone-throwing judgment, reducing human error. At the same time, through real-time data feedback and closed-loop control, the system can dynamically compensate for the impact of environmental changes. After the operator inputs the coordinates, the entire process from target identification, path planning, precise docking to stone-throwing triggering can be automated, achieving high-precision stone-throwing operations and avoiding environmental impact problems.

[0069] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An unprotected intelligent rock-throwing device for the underside of a bridge in the open sea, characterized in that, It includes a transverse track, which is fixed to the bridge deck. A lifting beam is slidably connected below the transverse track. The lifting beam moves along the transverse track. A longitudinal track is fixedly connected to the lifting beam. An electric hoist is installed on the longitudinal track. The electric hoist moves along the longitudinal track. A hook is set on the electric hoist, so that stones can be thrown from the bottom of the bridge through the hook. The electric hoist includes a moving mechanism and a lifting mechanism. The moving mechanism is fixedly connected to the lifting mechanism. The moving mechanism is equipped with a traveling wheel and a first motor. The traveling wheel is rolledly connected to the longitudinal track. The output end of the first motor is driven by the traveling wheel to drive the traveling wheel to move on the longitudinal track, thereby driving the lifting mechanism to move on the longitudinal track. The lifting mechanism is equipped with a second motor and a wire rope drum. The hook is fixedly connected to the wire rope on the wire rope drum. The output end of the second motor is fixedly connected to the wire rope drum. The second motor drives the wire rope drum to rotate forward or backward to drive the hook to rise or fall. The longitudinal track includes a straight track and an ascending track, which are fixedly connected. The top of the ascending track is greater than or equal to the height of the bridge deck. The ascending track includes an ascending section and a top section. The ascending section and the top section are connected by an arc to form the first arc track section. The ascending section and the straight track are connected by an arc to form the second arc track section. The traveling wheel includes a gear wheel and a round wheel. The gear wheel is fixedly connected to the round wheel and is located outside the round wheel. The rising rail is provided with a rack protrusion that matches the gear wheel. The traveling wheel moves on the straight rail via the round wheel, and the traveling wheel moves on the rising rail via the coordinated movement of the round wheel and the gear wheel.

2. The unprotected offshore bridge-bottom intelligent rock-throwing device according to claim 1, characterized in that, Multiple clamping devices are fixedly connected to the transverse track. The transverse track is secured to the bridge deck through the clamping devices. The clamping devices include an upper clamping block and a lower clamping block. The upper clamping block has a first screw hole and the lower clamping block has a second screw hole. A connecting screw is screwed between the first screw hole and the second screw hole. The lower clamping block is fixedly connected to the transverse track.

3. The unprotected offshore bridge-bottom intelligent rock-throwing device according to claim 2, characterized in that, The connecting screw includes a first thread and a second thread. The first thread and the second thread are opposite threads. The first thread is adapted to the first threaded hole, and the second thread is adapted to the second threaded hole. Rotating the connecting screw causes the upper clamping block and the lower clamping block to clamp the bridge surface.

4. The unprotected offshore bridge-bottom intelligent rock-throwing device according to claim 2, characterized in that, The upper clamping block has a wheel guard recess, and a buffer layer is installed inside the wheel guard recess. The wheel guard recess abuts against the wheel guard on the bridge deck through the buffer layer.

5. The unprotected offshore bridge-bottom intelligent rock-throwing device according to claim 2, characterized in that, The bottom surface of the lower clamping block has a sliding groove, in which a slider is slidably connected. The bottom of the connecting screw is connected to a base support, which can rotate relative to the connecting screw. A first diagonal brace is hinged to the slider, and the end of the first diagonal brace away from the slider is hinged to the base support. A top support is connected to the top of the connecting screw, which can rotate relative to the connecting screw. A fixed seat is provided on the upper clamping block, and the fixed seat and the top support are fixedly connected by a second diagonal brace. A hexagonal nut is fixedly connected to the connecting screw. Rotating the hexagonal nut causes the connecting screw to rotate.

6. A method for intelligent rock-throwing under an unprotected offshore bridge, using the intelligent rock-throwing device for unprotected offshore bridges as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Fill sandbags or gravel into special net bags and transport them to the designated area on the bridge surface by transport vehicles; S2. The bridge crane lifts the net bag to the edge of the bridge deck, and the electric hoist moves it to the top of the rising rail. S3. The electric hoist is attached to the net bag. The crane moves the net bag to the connection position between the straight rail and the rising rail. The electric hoist hook remains attached but does not bear any load. S4. The electric hoist gradually applies force until it fully supports the net bag, then the crane disconnects. S5. Based on the target rock-throwing coordinates, adjust the lifting beam and electric hoist using a multi-modal positioning system to lower the net bag to 1.0 m directly above the rock-throwing point. S6. The intelligent sensing unit of the multimodal positioning system detects the stone-throwing position in real time. If the position matches, the stone-throwing is executed; otherwise, the stone-throwing is dynamically adjusted.

7. The intelligent rock-throwing method under an unprotected offshore bridge as described in claim 6, characterized in that, Multimodal positioning systems include: The Gray busbar positioning system, laid on the transverse and longitudinal tracks, is used to detect the planar coordinates of the hook; A rotary encoder mounted on the first motor calculates the vertical coordinates of the net bag based on the length of the wire rope being extended and retracted. The hook is equipped with a motion sensing unit, including a sonar ranging module and a visual recognition module; After the target coordinates of the rock-throwing are input, the multimodal positioning system automatically plans the path, controls the lifting beam and electric hoist to move to the target position, and dynamically corrects the spatial pose of the net bag through the data transmitted by the sonar ranging module and the visual recognition module. The visual recognition module compares the real-time image with the preset rock-throwing area. If the matching degree exceeds the threshold, the rock-throwing is triggered; otherwise, the deviation is reported and the positioning is re-established. The visual recognition module uses deep learning algorithms to identify the boundary of the area to be thrown through a pre-trained rock-throwing area segmentation model, and combines sonar data and visual recognition results to construct a three-dimensional rock-throwing decision space, thereby achieving adaptive rock-throwing positioning under complex sea conditions.

Images