Hoisting test method of short-arm underwater hoisting mechanism
By constructing an adjustable underwater test platform, the problem that short-arm underwater cranes cannot directly lift heavy objects has been solved, improving the accuracy and economy of test data, avoiding the impact of silt adsorption and the need for large crane vessels.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CCCC FOURTH HARBOR ENG CO LTD
- Filing Date
- 2026-01-16
- Publication Date
- 2026-04-10
AI Technical Summary
In existing technologies, the lifting point of short-arm underwater cranes is only slightly above the water surface, making it impossible to lift heavy objects directly from the lowest point on the seabed. This results in silt adsorption affecting the accuracy of test data, and large crane vessels are required to recover the heavy objects after the test, increasing costs and extending the cycle.
An adjustable underwater test platform was constructed, and the suspended load was pre-fixed on the support platform and launched into the water as a whole with the inclined ship frame. The barge was connected to the platform through the immersed tube and the load was lifted simultaneously. After the test was completed, the platform was recovered to the shore as a whole to avoid the suspended load from contacting the silt on the bottom of the water.
It significantly improved the accuracy of test data, reduced test costs, shortened test cycles, and increased economic efficiency and test reliability.
Smart Images
Figure CN121823418A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of ship crane testing technology, and in particular to a lifting test method for a short-arm underwater crane mechanism. Background Technology
[0002] During the testing of underwater lifting mechanisms on immersed tube installation barges, conventional lifting test methods have significant limitations. Because the lifting point of a short-arm lifting mechanism is only slightly above the water surface, it cannot directly lift heavy objects from the lowest point on the seabed as a long-arm crane can. Traditional methods require the heavy object to be pre-sunk to a designated location on the seabed, followed by moving the immersed tube installation barge above the object for connection and lifting. However, the silt on the seabed continuously attracts the heavy object, requiring additional suction to be overcome during lifting, distorting the measured load values and failing to accurately reflect the performance parameters of the lifting mechanism, severely impacting the accuracy and reliability of the test data. Furthermore, after the test, the heavy object remains on the seabed, necessitating the use of large crane vessels for retrieval, which significantly increases equipment rental and operating costs, prolongs the test cycle, and reduces overall economic efficiency. These problems have long existed in existing technologies, restricting the feasibility and practicality of underwater lifting tests. Therefore, existing technologies urgently need improvement to address these issues. Summary of the Invention
[0003] To address the shortcomings of the existing technology, this invention provides a lifting test method for a short-arm underwater crane, which has the advantages of improving the accuracy of test data, reducing test costs, and shortening the test cycle.
[0004] This invention is achieved using the following technical solution: A lifting test method for a short-arm underwater crane includes the following steps: S1. Construct an adjustable underwater test platform: Erect a support platform between two inclined boat frames, pre-fix the suspended load to the support platform, and then launch the inclined boat frame equipped with the suspended load and the support platform as a whole into the water and sink it to the specified underwater depth; S2. Positioning and connection of the crane vessel: Move the immersed tube installation barge to the designated position, so that it is positioned between the suspended loads on the two bearing platforms, and connect the lifting point of each short boom crane mechanism to one of the suspended loads. S3. Synchronous lifting test: Operate the two lifting mechanisms to synchronously lift the corresponding loads and conduct a lifting test; S4. Heavy object recovery: After the test is completed, the suspended heavy object is placed back on the bearing platform, and the inclined boat frame and the bearing platform are recovered as a whole to the shore.
[0005] Furthermore, the supporting platform includes multiple I-beams arranged in parallel along the transverse direction, with each I-beam's two ends fixedly connected to a corresponding inclined ship frame.
[0006] Furthermore, the outermost I-beams on both sides of the bearing platform are double beam structures arranged side by side, while the I-beams between the outermost I-beams on both sides of the bearing platform are multiple single beam structures arranged in parallel and at equal intervals.
[0007] Furthermore, the I-beam is an HM-shaped steel beam.
[0008] Furthermore, in step S2, the immersed tube installation barge is positioned by its own anchoring equipment and fixed facilities set on the shore.
[0009] Furthermore, the immersed tunnel installation barge has multiple anchor winches, which are connected to winches on the shore via steel cables to achieve positioning and attitude fine-tuning of the immersed tunnel installation barge.
[0010] Furthermore, in step S1, the inclined boat frame is controlled by a cable winch to slide into the water and be retrieved along a preset inclined track.
[0011] Furthermore, prior to step S1, a feasibility verification step for the test water depth is also included: Obtain the draft parameters of the immersed tube installation barge under relevant test conditions; Determine the lowest possible placement position of the load-bearing platform and the suspended load on the inclined ship frame; Under a predetermined extreme low water level benchmark, calculate the effective working space of the lifting point of the short boom crane at the lowest possible placement position; When the effective working space is greater than the lifting point travel required due to the change in draft of the immersed tube installation barge, the test water depth requirement is deemed met.
[0012] Furthermore, the feasibility verification of the test water depth specifically includes: Below the 0m tidal reference plane, place the inclined ship frame and the supporting platform carrying the suspended load at their lowest available position; Measure the actual clearance H between the end of the lifting point of the short boom crane and the lifting point of the load at this time; Calculate the draft change ΔD of the immersed tube installation barge as it transitions from the no-load test state to the overload test state; If H is satisfied If ΔD is obtained, it is determined that the specified depth meets the test requirements when the tide level is 0m.
[0013] Furthermore, the draft under no-load test conditions is 1m, the draft under overload test conditions is 2.66m, the draft change ΔD is 1660mm, and the measured clearance distance H is 1755mm.
[0014] Compared with the prior art, the beneficial effects of the present invention include at least the following: This invention constructs an adjustable underwater test platform, pre-fixing the suspended load onto the support platform. The platform is then launched into the water as a whole along with the inclined vessel frame, effectively avoiding direct contact between the suspended load and the underwater silt, thus eliminating the influence of silt suction on the accuracy of the test results. Compared to the traditional method of placing the load directly on the seabed, this method significantly improves the reliability of the test data. Furthermore, after the test, the inclined vessel frame and support platform can be retrieved as a whole to the shore, eliminating the need for additional large crane vessels for underwater load transport, greatly reducing the cost of recovering the suspended load after the test and improving economic efficiency. This method has the advantages of improving the accuracy of test data, reducing test costs, and shortening the test cycle. Attached Figure Description
[0015] Figure 1 This is a schematic diagram of the positioning of the immersed tube installation barge according to an embodiment of the present invention; Figure 2 This is a schematic diagram of launching the inclined ship frame according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a suspended load on a support platform according to an embodiment of the present invention; Figure 4 This is a schematic diagram of a short-arm crane mechanism performing lifting operations according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the assembly between the support platform and the two inclined ship frames according to an embodiment of the present invention; In the diagram: 1. Inclined frame; 2. Load-bearing platform; 21. Double beam structure; 22. Single beam structure; 3. Lifting heavy objects; 4. Barge for immersed tube installation; 41. Short-arm crane mechanism; 5. Anchor winch; 6. Steel cable; 7. Winch; 8. Cable winch. Detailed Implementation
[0016] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided to make the invention more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore repeated descriptions of them will be omitted.
[0017] The terms used to express position and direction in this invention are illustrated with reference to the accompanying drawings, but changes can be made as needed, and all such changes are included within the scope of protection of this invention.
[0018] like Figures 1 to 5 As shown, the present invention provides a lifting test method for a short-arm underwater crane, comprising the following steps: S1. Construct an adjustable underwater test platform: Erect a support platform 2 between two inclined boat frames 1, pre-fix the suspended weight 3 onto the support platform 2, and then lower the inclined boat frame 1 equipped with the suspended weight 3 and the support platform 2 into the water as a whole, and sink them to the specified underwater depth. S2. Positioning and connection of the crane vessel: Move the immersed tube installation barge 4 to the designated position, so that it is positioned between the suspended loads 3 on the two bearing platforms 2, and connect the lifting point of each short boom crane 41 to one of the suspended loads 3. S3. Synchronous lifting test: Operate the two lifting mechanisms to synchronously lift the corresponding lifting load 3 and conduct a lifting test; S4. Heavy object recovery: After the test is completed, the suspended heavy object 3 is placed back on the bearing platform 2, and the inclined boat frame 1 and the bearing platform 2 are recovered as a whole to the shore.
[0019] In this embodiment, in step S1, an adjustable underwater test platform is constructed. The "adjustable" characteristic of this platform is reflected in its ability to be positioned at different water depths or locations. A support platform 2 is erected between two inclined boat frames 1. The support platform 2 can be placed and fixed between the two inclined boat frames 1, for example, by mechanical fasteners, clamps, or temporary welding. The inclined boat frames 1 provide a guide rail. Subsequently, a suspended load 3 is pre-fixed to the support platform 2. The suspended load 3 can be securely fixed to the support platform 2 by means of chains, wire ropes, or special clamps to prevent displacement during launching and testing. Next, the inclined boat frame 1 equipped with the suspended load 3 and the support platform 2 are launched as a whole and submerged to a specified underwater depth. This overall launching process can be carried out by large shore-based lifting equipment or by a controlled sliding mechanism, such as using pulley blocks and cable systems, to allow the entire assembly to smoothly slide into the water along the inclined boat frame 1. The submersion depth can be monitored in real time by a depth sensor.
[0020] In step S2, the immersed tunnel installation barge 4 is moved to the designated position. The barge can be moved using its own propulsion system or with the assistance of a tugboat. Initial positioning can be achieved visually or with basic GPS assistance. The immersed tunnel installation barge 4 is positioned between the two loads 3 on the two support platforms 2, ensuring that the short-arm crane 41 on the barge is accurately aligned and connected to the loads 3. Subsequently, the lifting points of each short-arm crane 41 are connected to a corresponding load 3. The connection operation can be performed using standard marine shackles, hooks, or quick-release connectors, which can be installed manually or with remote assistance.
[0021] In step S3, a synchronous lifting test is conducted. Two short-boom crane mechanisms 41 are operated to synchronously lift their corresponding loads 3. The two short-boom crane mechanisms 41 can be operated by their respective operators using independent control levers, with coordination between operators via vision or radio to achieve synchronous lifting. Alternatively, a basic linkage control system can be used to ensure consistent movement between the two mechanisms. The lifting test typically involves raising the load 3 to a preset height and holding it for a period of time while monitoring the lifting load, mechanism stability, and other relevant parameters.
[0022] In step S4, after the test is completed, the short-arm crane 41 slowly lowers the suspended load 3, ensuring its safe return to the predetermined position on the support platform 2. Subsequently, the inclined frame 1 and the support platform 2 are retrieved together and brought back to the shore. The retrieval process is the reverse of the launching process. The entire assembly can be lifted using shore-based lifting equipment, or pulled back to the shore along a ramp track using a controlled sliding mechanism, such as a winch and cable system.
[0023] This method constructs an adjustable underwater test platform, pre-fixing the suspended load 3 onto the support platform 2, and then launching it into the water as a whole with the inclined boat frame 1 and the support platform 2. This effectively avoids direct contact between the suspended load 3 and the bottom silt, thus eliminating the influence of silt suction on the accuracy of the test results. Compared to the traditional method of placing the load directly on the bottom, this method significantly improves the reliability of the test data. Furthermore, after the test, the inclined boat frame 1 and the support platform 2 can be recovered to the shore as a whole, eliminating the need for additional large crane vessels for underwater transport of the suspended load 3, greatly reducing the cost of recovering the load 3 after the test and improving economic efficiency. This method has the advantages of improving the accuracy of test data, reducing test costs, and shortening the test cycle.
[0024] In a preferred embodiment, the bearing platform 2 includes multiple I-beams arranged in parallel along the transverse direction, with each I-beam having its two ends fixedly connected to the corresponding inclined ship frame 1.
[0025] In this embodiment, by designing the bearing platform 2 as composed of multiple horizontally parallel I-beams, and fixing both ends of these I-beams to the inclined frame 1, a stable and load-bearing adjustable underwater test platform is constructed. Specifically, the I-beams, with their unique cross-sectional shape, provide strong bending stiffness and load-bearing capacity, effectively dispersing and supporting the enormous load generated by the suspended load 3. The parallel arrangement of multiple I-beams allows the load to be evenly distributed throughout the platform, avoiding local stress concentration, thereby significantly improving the overall stability and deformation resistance of the platform. Furthermore, the fixed connection between the I-beams and the inclined frame 1 ensures that the bearing platform 2 and the inclined frame 1 form a rigid whole, allowing the load of the suspended load 3 to be reliably transferred from the bearing platform 2 to the inclined frame 1, and further to the underwater or shore support structure. This integrated structural design effectively avoids the risk of deformation, damage, or detachment from the inclined frame 1 of the bearing platform 2 due to excessive load or unstable connection during the launching, lifting, and recovery of the heavy object 3, thus ensuring the safety, stability, and accuracy of the entire lifting test process.
[0026] In a preferred embodiment, the I-beams located at the outermost edges on both sides of the bearing platform 2 are double beam structures 21 arranged side by side, and the I-beams located between the outermost edges of the I-beams on both sides of the bearing platform 2 are multiple single beam structures 22 arranged in parallel and at equal intervals.
[0027] In this embodiment, the double-beam structure 21 refers to the arrangement of two closely spaced I-beams side-by-side at the outermost edge of the load-bearing platform 2, instead of using a single I-beam for support, forming a composite structure with higher section modulus and bending stiffness. This design aims to significantly enhance the load-bearing capacity and deformation resistance of the platform's edge area, as these areas are typically connected to the inclined frame 1 and bear the main load transfer. This can be achieved by tightly fixing the two I-beams together through welding, bolting, or riveting, making them a unified whole that shares the load. The single-beam structure 22 refers to the use of individual I-beams as supporting members within the inner area of the load-bearing platform 2, i.e., between the two double-beam structures 21. These single beams are arranged parallel at the same spacing, jointly supporting the suspended load 3 on the platform. This can be achieved by fixing these single beams to the inclined frame 1 through welding or bolting, forming a continuous load-bearing surface.
[0028] This embodiment effectively improves the overall performance of the underwater lifting test platform by optimizing the beam structure layout of the bearing platform 2. Specifically, a double-beam structure 21 arranged side by side is adopted at the outermost edge of both sides of the bearing platform 2, which significantly enhances the local stiffness and load-bearing capacity of the platform edge area. These edge areas are the key parts connecting the bearing platform 2 and the inclined frame 1, and are also the areas that bear the greatest stress concentration during the lifting and placement of the suspended load 3. The double-beam structure 21 can more effectively disperse and transfer the load from the suspended load 3, reduce the local stress peak, and thus avoid structural deformation or damage due to insufficient local strength. At the same time, the I-beams located between the double-beam structures 21 at the outermost edge of both sides of the bearing platform 2 adopt multiple single-beam structures 22 arranged in parallel and equidistantly. These single beams serve as intermediate supports and can evenly bear the suspended load 3. This modular beam structure design allows the entire load-bearing platform 2 to achieve higher overall bending and torsional stiffness while maintaining a certain weight and manufacturing cost. This ensures that the platform can stably and reliably support the suspended load 3 during underwater lifting tests, effectively resisting the impact of water flow and load changes, thereby guaranteeing the smooth progress of the test and the accuracy of the data.
[0029] In a preferred embodiment, the I-beam is an HM-shaped steel beam.
[0030] In this embodiment, HM-shaped steel, or wide-flange H-beam, is a type of H-section steel with wide flanges and a relatively small web height. Its design features include wider and more uniformly thicker flanges, resulting in a section modulus and moment of inertia that are typically superior to ordinary I-beams for the same weight, thus giving it stronger bending resistance and torsional stiffness. HM-shaped steel is usually manufactured using a hot-rolling process, ensuring material uniformity and reliable mechanical properties. In structural design, HM-shaped steel can serve as main or secondary beams, connected to other components through welding, bolting, or other methods to form a stable load-bearing structure. Furthermore, the standardized production of HM-shaped steel facilitates material procurement and construction. Due to the wide flanges and relatively small web height of the HM-shaped steel section, it helps to evenly distribute loads and reduce local stress concentration, thereby enhancing the structural stability and safety of the entire load-bearing platform 2. This superior mechanical performance ensures that the platform can reliably support the heavy object during the processes of launching, sinking, lifting, and recovering the load, and resist the impact of water flow and dynamic loads during lifting. This effectively avoids test interruptions or safety hazards caused by excessive deformation or failure of the beam, thus ensuring the smooth progress of the underwater lifting test.
[0031] In a preferred embodiment, in step S2, the immersed tube installation barge 4 is positioned by its own anchoring equipment and fixed facilities set on the shore.
[0032] In this embodiment, after the immersed tube installation barge 4 is moved to the designated position, it is initially secured using its onboard anchoring equipment (e.g., bow and stern anchors). Simultaneously, the barge's sides are connected to fixed facilities (e.g., shore-based mooring bollards or ground anchors) via mooring lines. This positioning method, combining shipboard anchoring and shore-based mooring, provides the barge with multi-point, multi-directional mooring forces, effectively resisting the influence of environmental factors such as water flow and waves, as well as the dynamic loads generated during the lifting operation, on the barge's position and attitude. By precisely adjusting the tension of the anchor chain and mooring lines, high-precision positioning of the immersed tube installation barge 4 in the water can be achieved, ensuring its stability throughout the lifting test. This allows the short-arm crane 41 to accurately dock with the underwater load 3 and successfully conduct synchronous lifting tests. This stable positioning mechanism is crucial for ensuring the accuracy and safety of underwater lifting tests.
[0033] Specifically, the immersed tunnel installation barge 4 has multiple anchor winches 5, which are connected to the winches 7 on the shore via steel cables 6, so as to realize the positioning and attitude fine adjustment of the immersed tunnel installation barge 4.
[0034] In this embodiment, a multi-point mooring system is constructed by installing multiple anchor winches 5 on the immersed tube installation barge 4 and connecting these anchor winches 5 to multiple winches 7 on the shore via steel cables 6. When positioning and attitude fine-tuning of the immersed tube installation barge 4 are required, operators can independently or collaboratively control the raising and lowering speed and tension of each anchor winch 5 based on the barge's real-time position and attitude information. For example, by tightening the steel cable 6 in the bow direction and loosening the steel cable 6 in the stern direction, the barge can be moved forward; by tightening the steel cable 6 on the port side and loosening the steel cable 6 on the starboard side, the barge's lateral position or heading can be adjusted. This multi-point, controllable traction method allows the barge not only to be fixed in a designated position but also to have its heel, trim, and heading attitudes finely adjusted. Compared to relying on a single or limited anchoring equipment, this significantly improves the stability and operational precision of the barge during underwater lifting tests, thereby ensuring the verticality of the suspended load 3 and the reliability of the test.
[0035] In a preferred embodiment, in step S1, the inclined boat frame 1 is controlled by the cable winch 8 to slide into the water and be retrieved along a preset inclined track.
[0036] In this embodiment, the coordinated action of the cable winch 8 and the preset inclined track enables precise and stable control over the launching and recovery processes of the heavy-duty test platform. Specifically, when the inclined boat frame 1 and the supporting platform 2 need to be slid into the water as a whole, the cable winch 8 releases the cable through its drum, and the cable is connected to the inclined boat frame 1. Under the action of gravity, the inclined boat frame 1 moves downward along the preset inclined track. At this time, the cable winch 8 effectively restricts and adjusts the downward speed of the inclined boat frame 1 by precisely controlling the release speed and tension of the cable, preventing it from accelerating out of control due to gravity, ensuring that the inclined boat frame 1 can smoothly and safely slide into the water, and finally sink to the predetermined underwater depth. When the test is completed and the inclined boat frame 1 and the supporting platform 2 need to be recovered as a whole, the cable winch 8 operates in reverse, applying traction force to the inclined boat frame 1 by winding the cable. The traction force overcomes the resistance of the inclined boat frame 1 in the water, the friction of the track, and the component of gravity along the slope, enabling the inclined boat frame 1 to move upwards along the preset inclined track until it is completely retrieved to the shore. During this process, the control system of the cable winch 8 continuously monitors and adjusts the traction force and speed to ensure the smoothness and safety of the retrieval process, effectively solving problems such as loss of control, uneven force, and safety hazards that may be caused by manual operation or simple mechanical methods.
[0037] In a preferred embodiment, a feasibility verification step for the test water depth is included before step S1: Obtain the draft parameters of the immersed tube installation barge 4 under relevant test conditions; Determine the lowest possible placement position of the bearing platform 2 and the suspended load 3 on the inclined ship frame 1; Under a predetermined extreme low water level benchmark, calculate the effective working space of the lifting point of the short boom crane 41 at the lowest possible placement position. When the effective working space is greater than the lifting point travel required due to the change in draft of the immersed tube installation barge 4, the test water depth requirement is deemed to be met.
[0038] In this embodiment, a feasibility verification step for the test water depth is introduced before constructing and launching the adjustable underwater test platform to ensure the smooth progress and safety of the test. This verification step first obtains the draft parameters of the immersed tube installation barge 4 under different test conditions. These parameters are key data for evaluating the hull immersion depth of the barge during underwater operations. Simultaneously, the lowest possible placement position of the bearing platform 2 and the suspended load 3 on the inclined frame 1 is determined, providing a benchmark for the lowest point of the lifting point of the short-arm crane 41 during underwater operations. Based on this, and combined with a predetermined extreme low water level benchmark, the effective working space of the lifting point of the short-arm crane 41 at the lowest possible placement position is calculated. This effective working space represents the maximum range of downward operation that the short-arm crane 41 can achieve under the most unfavorable water level conditions. Subsequently, this effective working space is compared with the lifting point travel required due to changes in the draft of the immersed tube installation barge 4. During the lifting test of the immersed tube installation barge 4, the draft of the load 3 changes due to loading and unloading, causing a relative displacement of the lifting point of the short-arm crane 41 relative to the underwater load 3, i.e., a lifting point stroke. By comparison, when the effective working space is greater than the lifting point stroke, it can be determined that the current test water depth meets the requirements. This verification mechanism ensures that the impact of water depth conditions on the operation of the short-arm crane 41 has been fully assessed and confirmed before the actual lifting test begins, avoiding the problem of the lifting point being unable to operate normally due to insufficient water depth or draft changes, thereby improving the reliability and safety of the test.
[0039] As a preferred embodiment, the feasibility verification of the test water depth specifically includes: Below the 0m tidal reference plane, the inclined ship frame 1 carrying the suspended load 3 and the supporting platform 2 are placed at their lowest available position; Measure the actual clearance H between the end of the lifting point of the short boom crane 41 and the lifting point of the suspended load 3 at this time; Calculate the change in draft ΔD of the immersed tube installation barge 4 as it transitions from the no-load test state to the overload test state; If H is satisfied If ΔD is obtained, it is determined that the specified depth meets the test requirements when the tide level is 0m.
[0040] In this embodiment, the 0m tidal reference plane refers to a standardized water level reference point, typically representing the local lowest astronomical tide level or a preset extreme low water level. Verification under this reference plane aims to simulate the most unfavorable water level conditions to ensure the test can be conducted safely under any tidal conditions. Placing the inclined frame 1 carrying the suspended load 3 and the supporting platform 2 at their lowest available position means lowering the entire test setup to its lowest design depth, further simulating the operating scenario of the short-boom crane 41 under extreme conditions. This operation can be achieved through precise control of the cable winch 8 or the hydraulic lowering system, ensuring the test setup accurately reaches the preset lowest position. The measured clearance distance H refers to the actual vertical distance between the end of the lifting point of the short-boom crane 41 and the lifting point of the suspended load 3 under the aforementioned extreme conditions. This distance directly reflects the actual space available for lifting the suspended load 3 using the short-boom crane 41 at the lowest water level and lowest placement position. This measurement can be achieved in several ways. For example, it can be performed non-contactly using an underwater sonar rangefinder, or directly by using an underwater measuring rod equipped with a scale. It can also be assisted by an underwater camera for manual observation and recording. The change in draft ΔD refers to the change in draft of the immersed tube installation barge 4 from no load (empty test state) to full load (overload test state). This change reflects the vertical sinking distance of the barge due to the increased load during actual lifting operations. This change can be obtained by consulting the barge's load-draft curve, or by actually measuring the vertical distance between the barge's waterline and the keel under different load conditions and calculating the difference. H ΔD is a crucial criterion that ensures that even at the 0m datum level, when the immersed tube installation barge 4 experiences its maximum draft (ΔD) due to lifting a heavy object, there is still sufficient clearance (H) between the lifting point of the short-arm crane 41 and the lifting point of the heavy object 3. This prevents collisions between the lifting point and the heavy object 3 or hinders successful lifting. If this condition is met, it can be definitively determined that the preset test water depth is safe and feasible under the extremely low water level of 0m. This determination can be manually verified by operators based on measurement and calculation data, or it can be automatically judged and prompted by the logic unit integrated into the test control system.
[0041] This embodiment addresses the feasibility of conducting lifting tests in complex underwater environments by establishing a specific verification process under extremely low water conditions. First, at a 0m tidal reference level, the inclined frame 1 carrying the load 3 and the supporting platform 2 are lowered to their lowest usable position, ensuring the verification process is conducted under the most unfavorable conditions. Based on this, the measured clearance distance H between the lifting point of the short-arm crane 41 and the lifting point of the load 3 is precisely measured. This distance represents the actual lifting space available to the short-arm crane 41 under extreme conditions. Simultaneously, considering the draft change of the immersed tube installation barge 4 due to load variations during lifting, the scheme further calculates the draft change ΔD caused by the barge transitioning from an unloaded test state to an overloaded test state. By comparing the measured clearance distance H with the draft change ΔD—that is, determining whether H is greater than ΔD—it is possible to intuitively and quantitatively assess whether the test water depth meets the lifting requirements under extremely low water conditions at 0m tidal levels. This method concretizes the abstract effective working space and required lifting point travel into measurable physical quantities and introduces considerations under extreme low water level conditions, thus providing a more rigorous and reliable water depth feasibility verification mechanism, significantly improving the safety and accuracy of underwater lifting tests.
[0042] In a preferred embodiment, the draft under no-load test conditions is 1m, the draft under overload test conditions is 2.66m, the draft change ΔD is 1660mm, and the measured clearance distance H is 1755mm.
[0043] In this embodiment, by providing specific parameters for the feasibility verification step of the test water depth, the entire verification process becomes more accurate and operable. Specifically, by defining the draft as 1m in the unloaded test state and 2.66m in the overloaded test state, the draft change ΔD that the immersed tube installation barge 4 may experience during the lifting operation is accurately calculated to be 1660mm. Simultaneously, through actual measurement, the measured clearance distance H between the end of the lifting point of the short-arm crane 41 and the lifting point of the lifting load 3 under the most unfavorable working condition (tide level 0m, with the bearing platform 2 and the lifted load 3 at their lowest positions) is determined to be 1755mm. The introduction of these specific values allows for direct comparison between the measured clearance distance H and the draft change ΔD during the water depth feasibility verification. When the measured clearance distance H (1755mm) is greater than the draft change ΔD (1660mm), i.e., H... If the condition ΔD is met, it can be determined that the specified depth at a tide level of 0m meets the test requirements. This parameterized verification method avoids fuzzy judgments and ensures that the short-arm crane 41 still has sufficient working space under extremely low water conditions, effectively avoiding the risk of the suspended load 3 touching the bottom or insufficient lifting point stroke, thereby improving the safety and reliability of the lifting test.
[0044] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the invention without departing from the principles and spirit of the invention, and all such changes should fall within the protection scope of the claims of the present invention.
Claims
1. A lifting test method for a short-arm underwater crane, characterized in that, Includes the following steps: S1. Construct an adjustable underwater test platform: Erect a support platform between two inclined boat frames, pre-fix the suspended load to the support platform, and then launch the inclined boat frame equipped with the suspended load and the support platform as a whole into the water and sink it to the specified underwater depth; S2. Positioning and connection of the crane vessel: Move the immersed tube installation barge to the designated position, so that it is positioned between the suspended loads on the two bearing platforms, and connect the lifting point of each short boom crane mechanism to one of the suspended loads. S3. Synchronous lifting test: Operate the two lifting mechanisms to synchronously lift the corresponding loads and conduct a lifting test; S4. Heavy object recovery: After the test is completed, the suspended heavy object is placed back on the bearing platform, and the inclined boat frame and the bearing platform are recovered as a whole to the shore.
2. The lifting test method for the short-arm underwater crane according to claim 1, characterized in that, The support platform includes multiple I-beams arranged in parallel along the transverse direction, with each I-beam's two ends fixedly connected to a corresponding inclined ship frame.
3. The adjustable trial lifting method for the short-arm underwater crane vessel according to claim 2, characterized in that, The outermost I-beams on both sides of the load-bearing platform are double beam structures arranged side by side, while the I-beams between the outermost I-beams on both sides of the load-bearing platform are multiple single beam structures arranged in parallel and at equal intervals.
4. The adjustable trial lifting method for the short-arm underwater crane vessel according to claim 2, characterized in that, The I-beam is an HM-type steel beam.
5. The lifting test method for the short-arm underwater crane according to claim 1, characterized in that, In step S2, the immersed tube installation barge is positioned by its own anchoring equipment and fixed facilities set on the shore.
6. The lifting test method for the short-arm underwater crane according to claim 5, characterized in that, The immersed tunnel installation barge has multiple anchor winches, which are connected to winches on the shore via steel cables to enable positioning and fine-tuning of the immersed tunnel installation barge.
7. The lifting test method for the short-arm underwater crane according to claim 1, characterized in that, In step S1, the inclined boat frame is controlled by a cable winch to slide into the water and be retrieved along a preset inclined track.
8. The lifting test method for the short-arm underwater crane according to claim 1, characterized in that, Before proceeding to step S1, a feasibility verification step for the test water depth is also included: Obtain the draft parameters of the immersed tube installation barge under relevant test conditions; Determine the lowest possible placement position of the load-bearing platform and the suspended load on the inclined ship frame; Under a predetermined extreme low water level benchmark, calculate the effective working space of the lifting point of the short boom crane at the lowest possible placement position; When the effective working space is greater than the lifting point travel required due to the change in draft of the immersed tube installation barge, the test water depth requirement is deemed met.
9. The lifting test method for the short-arm underwater crane according to claim 8, characterized in that, The feasibility verification of the test water depth specifically involves: Below the 0m tidal reference plane, place the inclined ship frame and the supporting platform carrying the suspended load at their lowest available position; Measure the actual clearance H between the end of the lifting point of the short boom crane and the lifting point of the load at this time; Calculate the draft change ΔD of the immersed tube installation barge as it transitions from the no-load test state to the overload test state; If H is satisfied If ΔD is obtained, it is determined that the specified depth meets the test requirements when the tide level is 0m.
10. The lifting test method for the short-arm underwater crane according to claim 9, characterized in that, The draft under no-load test conditions is 1m, the draft under overload test conditions is 2.66m, the draft change ΔD is 1660mm, and the measured clearance distance H is 1755mm.