A method for water construction of a cross-sea bridge under severe sea conditions

Abstract

The present invention discloses a method for water construction of a cross-sea bridge under severe sea conditions, which comprises the following steps: Step 1: Obtain the simulated wave report of the construction sea area, so as to simulate the wave field conditions at each pier position; Step 2: Compile a two-element statistical table of wave periods and select the types of vessels; Step 3: Obtain the motion responses of the vessels; Step 4: Determine the vessel motion thresholds; Step 5: Calculate the workable vessel operation window periods according to the vessel motion responses and motion thresholds; Step 6: Determine the vessel types according to the work efficiency requirements; Step 7: Make on-site wave forecasts pier by pier; Step 8: Form a wave forecasting and vessel auxiliary decision-making system, and dispatch the vessels according to this system. The method of the present invention enables the management personnel to observe the sea conditions and vessel information in the construction sea area in the office, and uses the wave forecasting technology and the vessel window periods to put forward effective scheduling, improve the operation efficiency of the vessels at sea, and ensure the efficient construction of the vessels at sea.

Description

Technical Field

[0001] The present invention relates to the field of offshore ship construction for cross-sea bridges. More specifically, the present invention relates to a method for water construction of cross-sea bridges under harsh sea conditions. Background Art

[0002] With the booming development of China's economy, more and more engineering constructions are carried out in the marine environment. Compared with the calm inland rivers, the harsh surges often cause large swinging motions of construction ships. When the surges are large enough to exceed the allowable range of the construction ship's operation, it will be impossible to carry out operations that meet the accuracy requirements; even in more severe surges, the ship needs to go to the harbor anchorage for refuge. Therefore, it is necessary to seize the ship construction window period as much as possible for operations. On the other hand, since the number of ships involved in cross-sea bridge construction can reach dozens, but due to inconvenient transportation and communication, especially in overseas projects with more severe sea conditions, the organization and dispatching of construction ships are very difficult, often resulting in situations where the work efficiency is reduced, such as ships queuing up to dock at temporary terminals. Summary of the Invention

[0003] An object of the present invention is to provide a method for water construction of cross-sea bridges under harsh sea conditions, forming a method from ship selection to on-site auxiliary decision-making, enabling managers to observe the sea conditions and ship information in the construction sea area in the office, using wave prediction technology and ship window periods, proposing effective dispatching, improving the operation efficiency of offshore ships, and thus ensuring the efficient construction of offshore ships.

[0004] To achieve these and other advantages in accordance with the present invention, there is provided a method for water construction of cross-sea bridges under harsh sea conditions, including the following steps:

[0005] Step 1: Obtain the simulated wave hindcast of the construction sea area, so as to simulate the wave field conditions at each pier position;

[0006] Step 2: Compile a two-element statistical table of wave periods and statistically obtain the wave spectrum of the on-site irregular waves, so as to master the specific situation of wave distribution at each pier position on-site and select ships based on this;

[0007] Step 3: Based on the above simulated wave field conditions, obtain the motion responses of the above alternative ships;

[0008] Step 4: Determine the ship motion threshold according to the on-site construction technology;

[0009] Step 5: Calculate the constructible wave conditions, which are also the constructible ship operation window periods, based on the ship motion responses and motion thresholds;

[0010] Step 6: Determine the ship type according to the ergonomic requirements. Based on the wave conditions during the window period determined in Step 5 and combined with the wave height and period distribution in Step 2, determine the frequency at which the ship can operate.

[0011] Step 7: Forecast the waves at each pier site on-site.

[0012] Step 8: Form a wave forecasting and ship auxiliary decision-making system, and dispatch the ship according to this system.

[0013] Preferably, Step 1 is specifically as follows: Obtain the topography, wind field data, and boundary conditions of the construction sea area, and set them in the model. Use the WAVEWATCH3 mathematical model and SWAN model based on the dynamic spectral balance equation for simulation. Use the WAVEWATCH3 mathematical model for calculation in a large-scale coarse terrain grid, calculate the wave conditions at the boundary of the small-scale fine terrain grid, and then use this boundary condition as the boundary input for the SWAN model in the fine terrain grid for calculation, so as to simulate the wave field conditions at each pier site.

[0014] Preferably, use a wave monitor to monitor the wave field conditions at a certain point at each pier site for multiple months. After obtaining the monitoring data, correct the above model to improve the simulation accuracy of the wave field conditions at each pier site.

[0015] Preferably, Step 3 is specifically as follows: Based on the potential flow theory calculation method, calculate the motion response of the ship under the action of waves, the motion response of the ship's pitching and rolling. Simulate through the SESAM / HydroD developed by DNV of the Norwegian Classification Society, or use the ANSYS / AQWA potential flow analysis software for simulation, so as to obtain the relationship between the ship's motion response and the wave input parameters.

[0016] Preferably, in Step 5, the system contains a calculation formula for the regression of the ship's motion response to waves, so as to quickly obtain the ship's motion window period according to the ship's length, width, and draft information.

[0017] Preferably, in Step 5, the ship's motion response is the pitching motion response, and a condition of the wave height that can be constructed is defined for each second of the period.

[0018] Preferably, Step 7 is specifically as follows: Use a method similar to Step 1. By mastering the future wind field forecast data, obtain the wave forecast data for the next seven days, and combine the measured wave monitoring data obtained by the wave monitor to revise the forecast data, so as to obtain high-precision wave forecast data.

[0019] Preferably, step eight is specifically as follows: Wave forecast information, ship positioning information, construction window period setting, and construction efficiency records are recorded in the system. Among them, the ship positioning information is transmitted by the ship's GPS positioning. The position information of all ships and the current construction operation status are displayed on the system display screen. The data corresponding to the ships in the system includes the ship captain's name, contact information, and ship size information. When a ship needs to be dispatched, the dispatching personnel input the dispatch information. The system determines whether it is possible to operate within the set future time based on the predicted pier wave data. If it is possible to operate, the dispatch information is sent to the receiving end on the ship. If it is not possible to operate, the ship is dispatched to other construction areas for operation according to the actual situation. After receiving the information through the receiving end, the captain on the ship confirms the instruction by replying, thus completing this dispatch.

[0020] Preferably, the construction window period of the finally dispatched ship is compared with the ship operation window period calculated in step five. If there is a deviation, the ship construction window period is corrected by actually measuring the operation window period of the ship on-site.

[0021] Preferably, the construction operation window includes wave height, period, and wave direction information.

[0022] The present invention has at least the following beneficial effects:

[0023] 1. The present invention can vividly display the general layout plan of the cross-sea bridge construction project, sea conditions, and ship positions, thereby improving project organization management;

[0024] 2. The present invention can display the real-time wave monitoring data and ship GPS positioning information, thus achieving good monitoring;

[0025] 3. The present invention includes a complete set of key technologies for offshore construction, namely hydrographic conditions, ship motion response, determination of construction window period, judgment of whether a ship can operate, etc., which can help technicians better ensure capturing the construction window period;

[0026] 4. The present invention can set different window periods for each ship. When the sea conditions are too severe, it can help the construction ships better avoid risks, thereby ensuring the safety of offshore construction;

[0027] 5. Based on the construction accuracy required by the design, the present invention determines the window period range and constructs within the window period, thereby ensuring that the construction accuracy meets the construction requirements and guaranteeing the project quality;

[0028] 6. The auxiliary decision-making system of the present invention can improve the efficiency of offshore construction and reduce the construction cost.

[0029] Other advantages, objectives, and features of the present invention will be partially reflected by the following description and partially understood by those skilled in the art through the research and practice of the present invention. Description of the Drawings

[0030] Figure 1 This is the construction flow chart of the present invention. Detailed Description of the Invention

[0031] The present invention will be further described in detail below with reference to the accompanying drawings, so that those skilled in the art can implement it according to the text of the specification.

[0032] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials, unless otherwise specified, can all be obtained from commercial channels; in the description of the present invention, the terms "horizontal", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0033] Embodiment

[0034] As Figure 1 shown, the present invention provides a method for water construction of a cross-sea bridge under harsh sea conditions, including the following steps:

[0035] Step 1. Wave hindcast in the construction sea area; Generally speaking, due to the large scope of the cross-sea bridge and significant differences in wave conditions at each pier location, it is necessary to conduct wave hindcasts at each pier location. The wave hindcast method requires near-field and far-field terrain data, wind field data, boundary conditions, etc.; The terrain data uses the ETOPO1 (1 Minute Gridded Global Relief Data Collection) seabed terrain data of the one-minute grid global terrain dataset provided on the website of the National Oceanic and Atmospheric Administration (NOAA) of the United States. In the sea area near the pier, geological exploration data provided by the owner is also available. The driving wind field of the wave model is the GFS wind field, which is downloaded through the National Operational Model Archive and Distribution System (NOMADS) of the National Oceanic and Atmospheric Administration (NOAA) of the United States. The wind field data covers the globe, and the horizontal resolution is 0.25 degrees. For the construction sea area, the resolution is still relatively high, and local measured wind field data needs to be obtained. The land boundary data needs to be obtained from the owner because if the land boundary is a vertical wall, it will cause more wave reflections, and if it is a rubble mound breakwater, the wave reflections are smaller. Set the terrain, wind field data, and boundary conditions of the construction sea area in the model, and use the WAVEWATCH3 mathematical model and SWAN model based on the dynamic spectral balance equation for simulation. The WAVEWATCH3 mathematical model is used for calculation in the large-scale coarse terrain grid to calculate the wave conditions at the boundary of the fine terrain grid (small area), and then this boundary condition is used as the boundary input for the SWAN model in the fine terrain grid for calculation, so as to simulate the wave field conditions at each pier location. To improve the simulation accuracy, wave monitoring instruments can be used to monitor at a certain point on-site for multiple months to correct the calculation model. The wave forecast data is extended in the form of a broken line. The wave forecast method mainly uses the third-generation wave energy spectrum numerical models such as SWAN and WAVEWATCH-Ⅲ, and machine learning methods can also be considered for wave forecasting.

[0036] Step 2. Compile a statistical table of the two elements of wave period, and statistically obtain the wave spectrum of the irregular waves on-site, so as to master the specific situation of the on-site wave distribution and use it as the basis for ship type selection.

[0037] Step 3. Simulate the motion response of the alternative vessels under waves; Whether a construction vessel can meet the high-precision operation requirements is affected by factors such as the operation precision requirements, wave height, wave direction, wave period, etc. Based on the potential flow theory calculation method, the motion response of the vessel under the action of waves can be calculated. The motion response of the vessel's pitching and rolling can be simulated through SESAM / HydroD developed by DNV (Det Norske Veritas), or other potential flow analysis software such as ANSYS / AQWA can be used for simulation, so as to obtain the relationship between the vessel's motion response and the wave input parameters. The simulation accuracy of the wave forecast is continuously corrected according to the wave monitoring data, so as to further ensure that the construction window period can be accurately captured. In the optimization of the vessel operation window conditions, a six-degree-of-freedom monitoring device for the vessel can be used to record the pitching amplitude of the constructible vessel, so as to better determine the actual vessel operation window conditions. The system contains many calculation formulas for the regression of the vessel's motion response to waves, so that according to information such as the vessel's length, width, and draft, the motion window period of the vessel can be quickly obtained. When simulating the vessel's motion response, a vessel form drawing provided by the vessel construction party is used for modeling, and the vessel's motion response is obtained through simulation with three-dimensional potential flow software.

[0038] Step 4. Determine the vessel motion threshold; Determine the threshold of the vessel's motion response according to the on-site construction technology. For example, in the common pile driving precision, there are generally inclination requirements of 1 / 100, 1 / 150, and 1 / 200. For the 1 / 100 inclination of the pile foundation, considering a partial coefficient of 1.25, that is, the pitching and rolling deflection angle of the vessel's motion is 0.45 degrees; for the 1 / 150 inclination of the pile foundation, considering a partial coefficient of 1.25, that is, the pitching and rolling deflection angle of the vessel's motion is 0.3 degrees; for the 1 / 200 inclination of the pile foundation, considering a partial coefficient of 1.25, that is, the pitching and rolling deflection angle of the vessel's motion is 0.22 degrees; that is, when the inclination requirement of the pile foundation is 1 / 200, the allowable pitching and rolling angle of the vessel is within 0.22 degrees to ensure high-precision operation. For example, during the lifting operation, the vessel motion response threshold is 0.45°.

[0039] Step 5. Determine the vessel operation window period. According to the vessel's motion response and motion threshold, calculate the constructible wave conditions, which are also the constructible window periods. Since the wave conditions generally include three conditions: wave direction, period, and wave height, during actual construction, it is required to operate along the wave direction, that is, to limit the wave direction angle to 15° for operation. At this time, pitching will be the main factor in the vessel's motion response. Therefore, the pitching motion response is used as the limiting requirement for the wave window conditions. Generally speaking, the longer the wave period, the greater the vessel's motion response under the same wave height condition. And when limiting the extreme value of the vessel's motion response, the smaller the wave motion. Therefore, it is necessary to define a construction condition for the wave height for each second of the period.

[0040] Step 6: Determine the ship type according to the ergonomic requirements. Under severe sea conditions, usually more than 80% of the construction efficiency can be guaranteed, and then it can meet the requirements of the construction period, but it also depends on the specific project construction period requirements; at the same time, there is also a monsoon period in the wave conditions, that is, the waves are more severe in several months of the year, and relatively calm in the other months. The core of ship type selection is to meet the construction period arrangement with a more economical ship; according to the wave conditions in the determined window period in Step 5, combined with the wave height and period distribution in Step 2, determine the frequency at which the ship can operate.

[0041] Step 7: Forecast the waves pier by pier on site. Adopt a method similar to that in Step 1 to obtain the wave forecast data for the next seven days by mastering the future wind field forecast data. Usually, the forecast accuracy is relatively high for the next 1 day, and the accuracy for the next 3 days can also be trusted, but the accuracy of the wave data for the next 7 days is not high. The main consideration is the wave development trend.

[0042] Step 8: Form a wave forecast and ship auxiliary decision-making system; consider a system that combines technology and management, which can greatly improve the construction efficiency. A wave forecast and ship auxiliary decision-making system will be established. The system includes wave forecast information, ship positioning information, construction window period setting, construction efficiency record, etc. Among them, the ship positioning information is transmitted by the ship's GPS positioning, and the visualization of the ship's positioning data during construction is realized, and it enables project managers to observe the position information of all ships and the current construction operation situation in the dispatching office. When dispatching is required, click on the ship at the current position in the overall plan of the system, and the ship captain's name, contact information, ship size information, etc. will be displayed. When clicking to dispatch the ship to a certain pier for operation, the system will judge whether it is possible to operate in the next 3 hours, 6 hours, 9 hours, 12 hours, and 24 hours according to the future wave forecast data, as well as the percentage of the forecast wave height in the wave height allowable for operation. When the operator accepts the auxiliary decision-making information, if it is not possible to operate, the ship can be considered to be dispatched to other work areas for operation, thus avoiding the ineffective idle work of the ship. After reading the warning information and confirming the dispatch, the system will send a message to the captain, and after the captain accepts the message and replies with a confirmation instruction, this dispatch is completed. When the sea conditions are too severe, the ship auxiliary decision-making system will prompt the ship to return to the anchorage area for mooring. In the ship auxiliary decision-making system, when construction is possible, a green window will pop up for explanation, and when construction is not possible, a red underlined window will pop up for explanation. The system has collected the wave heights allowed for many ship operation types and continuously optimized them during use, so as to provide project managers with the window period for selecting specific ship operations, and each project can be adjusted according to the actual situation. The construction operation window includes wave height, period and wave direction information. Different types of operation ships are represented by different schematic points.

[0043] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those skilled in the art, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and the examples shown and described herein.

Claims

1. A method for underwater construction of a cross-sea bridge under severe sea conditions, characterized in that It includes the following steps: Step 1: Obtain the simulated wave report of the construction sea area, so as to simulate the wave field conditions at each pier location; Step 2: Compile a statistical table of the two elements of the wave period, and statistically analyze the wave spectrum of the on-site irregular waves, so as to master the specific situation of the wave distribution at each pier location on-site, and select the ship type based on this; Step 3: Based on the above simulated wave field conditions, obtain the motion responses of the above alternative ships; Step 4: Determine the ship motion threshold according to the on-site construction technology; Step 5: According to the ship motion response and the motion threshold, calculate the constructible wave conditions, which are also the constructible ship operation window periods; Step 6: Determine the ship type according to the work efficiency requirements. According to the wave conditions in the window period determined in Step 5, combined with the wave height and period distribution in Step 2, determine the constructible frequency of the ship; Step 7: Forecast the waves at each pier on-site; Step 8: Form a wave forecasting and ship auxiliary decision-making system, and dispatch the ships according to this system; The system records wave forecasting information, ship positioning information, construction window period settings, and construction work efficiency records. Among them, the ship positioning information is transmitted by the ship's GPS positioning. The position information of all ships and the current construction operation situation are displayed on the system display screen. The data corresponding to the ships in the system include the ship captain's name, contact information, and ship size information. When a ship needs to be dispatched, the dispatcher inputs the dispatch information. The system judges whether it can operate within the set future time according to the forecasted pier wave data. If it can operate, it sends the dispatch information to the receiving end on the ship. If it cannot operate, it dispatches the ship to other construction areas for operation according to the actual situation. After receiving the information through the receiving end, the captain on the ship confirms the instruction by replying, and thus completes this dispatch; Compare the construction operation window period of the finally dispatched ship with the ship operation window period calculated in Step 5. If there is a deviation, correct the ship construction window period through the on-site measured ship operation window period.

2. The method for water construction of a cross-sea bridge under severe sea conditions according to claim 1, characterized in that, The specific content of Step 1 is as follows: Obtain the terrain, wind field data, and boundary conditions of the construction sea area, and set them in the model. Use the WAVEWATCH3 mathematical model and the SWAN model based on the dynamic spectrum balance equation for simulation. Use the WAVEWATCH3 mathematical model for calculation in the large-scale coarse terrain grid, calculate the wave conditions at the boundary of the small-scale fine terrain grid, and then use the wave conditions at this boundary as the boundary input for the SWAN model in the fine terrain grid for calculation, so as to simulate the wave field conditions at each pier location.

3. The method for water construction of a cross-sea bridge under severe sea conditions according to claim 2, wherein Use a wave monitor to monitor the wave field conditions at a certain point at each pier location for multiple months. After obtaining the monitoring data, correct the above model to improve the simulation accuracy of the wave field conditions at each pier location.

4. The method for water construction of a cross-sea bridge under severe sea conditions according to claim 1, wherein The specific content of Step 3 is as follows: Based on the potential flow theory calculation method, calculate the motion response of the ship under the action of waves. The motion responses of the ship's pitching and rolling are simulated through SESAM / HydroD developed by DNV of Norway or by using the ANSYS / AQWA potential flow analysis software, so as to obtain the relationship between the ship's motion response and the wave input parameters.

5. The method for water construction of a cross-sea bridge under severe sea conditions according to claim 1, characterized in that, The system contains the calculation formula for the library regression of the ship's motion response to waves, so as to quickly obtain the ship's motion window period according to the ship's length, width and draft information.

6. The method for water construction of a cross-sea bridge under severe sea conditions as claimed in claim 1, wherein In Step 5, the ship's motion response is the pitching motion response, and a condition of the wave height that can be constructed is defined for each second of the period.

7. The method for water construction of a cross-sea bridge under severe sea conditions according to claim 3, wherein The specific content of Step 7 is as follows: Adopt a method similar to that in Step 1, obtain the wave forecast data for the next seven days by mastering the future wind field forecast data, and combine with the measured wave monitoring data obtained by the wave monitor to revise the forecast data, so as to obtain high-precision wave forecast data.

8. The method for water construction of a cross-sea bridge under severe sea conditions according to claim 1, characterized in that, The construction operation window contains wave height, period and wave direction information.

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