Study On Mooring Simulation And Calculation Of Pontoon In Three Gorges Reservoir Area

In recent years, with the175m impoundment of the three gorges reservoir, fairwayconditions are gradually improved. More and more large-scale ships, vessel speedcontinues to improve, so shipping industries are more and more prosperous in the threegorges reservoir area. Dry season and flood water of three gorges reservoir area have30meters water-fluctuation. It makes the length and force of each mooring line differentand pontoon mooring is more and more difficult. From broken cable accidents in recentyears, it puts forward higher requests for the mooring force. From the catering pontoonwharf of Chongqing port, it’s shown that the cable diameter and the number of cablesare based on the experience of experts. By establishing the pontoon mooring calculationmodel of Three Gorges reservoir area, it hopes that it can helps to reduce or eliminatebroken mooring accident due to mooring force and the pontoon mooring equipment ismore scientific and reasonable.The related channel data is collected and processed, the channel characteristicsof the main stream and tributaries are analyzed in three gorges reservoir area. Byanalyzing the pontoon mooring safety control factor, the calculation modelof wind, wave and flow are established. According to the calculation model ofwind pressure, the wind pressure in the transverse mooring force is larger thanlongitudinal mooring force. According to the width of the channel is limited in theThree Gorges Reservoir area, the pontoon is located in one side of terminal channel, it isnecessary to establish the model of pontoon force from ship-generated wave by passingship. A simulation result is based on the catering pontoon by collected data: the waveheight increases due to the increase of ship speed, and the wave mooring force isproportional to the wave height. The maximum wave mooring force is related to thenatural period of pontoon, and the period of maximum wave mooring force is longerthan the natural period; the number of maximum wave mooring force isn’t related towave period but the size of pontoon. The impact of floating objects is to beconsidered in the model of flow. By simulation analysis of it, the flow force in thelongitudinal mooring force is larger than transverse mooring force.Through the study of wind, wave and flow in the Three Gorges Reservoir, themooring force calculation model of pontoon was established. By collecting andprocesses the data of extreme weather, the boundary conditions of angle and the optimal layout are concluded. Then simulate and calculate the model: The lateral force of windis greater than the lateral force of wave, the lateral force of current is minimum; thelongitudinal force of current is maximum, next wind, the longitudinal force of wave isminimum. The mooring force order is: bow offshore anchor>territorial waters anchor>aft offshore anchor> head line>stern line>fore breast>aft breast> aft anchor. Anevaluation instance shows its validity. Comparison of current data and standard data, itknows the pontoon mooring force isn’t enough.The models of this paper provide reference for the inland berths construction andrelevant industry standards, data and references for the pontoon mooring layout, andtheoretical basis for pontoon mooring equipment.