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891.
A lumped-mass model of a marine evacuation chute is presented based on the equations of Kane. The effects of wind load, internal mass transport and the motions of the ends are included. A sample of predicted motions and tensions is presented for a typical extreme environmental condition. The model may be used to assess the behaviour of the chute structure under a variety of emergency evacuation scenarios. 相似文献
892.
利用放射性示踪沙定量观测长江口北槽航道抛泥区底沙运动 总被引:3,自引:0,他引:3
1991年6月在国际原子能机构的合作下,在长江口北槽航道上抛泥区进行了一次大规模的放射性示踪沙试验。示踪核素为钪-46,总活度为17.95×10~(10)Bq(4.85Ci),示踪沙投放总量为495g。本试验目的是通过定量观测底沙运移的方向、路线、速度和输沙率,以期为北槽航道上抛泥区今后能否继续作为抛泥区使用提供直观可靠论据。本次试验观测资料表明,在北槽航道上抛泥区,在中小讯期间,无论是涨潮时投放的示踪沙还是落潮时投放的示踪沙都受落潮流控制,并向北槽航道中段输移。据测量资料分析,在上口抛泥区投放的示踪沙最终沿着110°的运动方向以758m/d的运动速度,在269~#航标附近进入挖槽,单宽输沙率为47.8m~3/md。 相似文献
893.
Analysis of Wave Loads on A Semi-Submersible Platform 总被引:10,自引:0,他引:10
For the global and structural fatigue strength analysis of a semi-submersible platform, wave loads under design conditions are calculated by use of the three-dimensional boundary element method. Methods for calculating the forward-speed free-surface Green function are discussed and a computer program with this Green function is developed. According to the special rules, the wave loads under several typical design conditions of the platform are calculated. The maximum vertical bending moment, torsion moment and horizontal split force are determined from a series of contour maps of wave loads for the wave period of 5 to 18 seconds at a certain interval and the wave phase of 0°to 360°at a certain interval. The wave height is determined by the function of wave period with a given exceedance probability. The maximum wave loads under the combination of wave parameters are used as the input of hydrodynamic pressure in the three-dimensional finite element analysis process. The transfer functions of wave loads 相似文献
894.
In this study, the combined actions of waves and tidal currents in estuarine and coastal areas are considered and a 2D mathematical model for sediment transport by waves and tidal currents has been established in orthogonal curvilinear coordinates. Non-equilibrium transport equations of suspended load and bed load are used in the model. The concept of background concentration is introduced, and the formula of sediment transport capacity of tidal currents for the Oujiang River estuary is obtained. The Dou Guoren formula is employed for the sediment transport capacity of waves. Sediment transport capacity in the form of mud and the intensity of back silting are calculated by use of Luo Zaosen' s formula. The calculated tidal stages are in good agreement with the field data, and the calculated velocities and flow directions of 46 vertical lines for 8 cross sections are also in good agreement with the measured data. On such a basis, simulations of back silting after excavation of the waterway with a sand bar under complicated boundary conditions in the navigation channel induced by suspended load, bed load and mud by waves and tidal currents are discussed. 相似文献
895.
896.
本文提供了作者研制的三维内波及分层流水槽系统的背景技术资料。经源致三维内波的实验证实 ,利用该水槽系统中的双缸制取分层水系统可快速制取所需的分层水 ,不必利用分子扩散而 1次得到预先设置的密度剖面。同时 ,还介绍了利用该水槽系统进行的 1个典型的源致内波的内波增阻实验。从所获得的增阻实验结果得知 ,对于一给定的分层、拖曳速度和水下回转体 ,存在唯一 1个内Froude数使得强迫源受到最大的内波增阻。大量的实验证实 :该水槽系统是研究三维自由和强迫内波的 1个基本实验系统。 相似文献
897.
Xiaohong Bai Wubin He Jungang Jia Yunshan Han 《Marine Georesources & Geotechnology》2006,24(3):173-182
Static load tests on pile group with prototype size were carried out in order to study the behavior and the working properties of the cap—pile group—soil interaction in the pile group foundation. The soil resistance under the cap, the pile shaft resistance and the tip resistance were measured by installing various measuring gauges. Based on these test results, the cap—pile group—soil interaction characteristics were analyzed. The regulations of the soil reaction on the cap, the shaft resistance and the tip resistance of pile, the mechanism of load transfer have been discussed with comparison to the result of the single pile tests. The bearing capacity of pile group is greater than the sum of the bearing capacity of the single pile obtained from testing in the same site in pile group foundation in the case presented here. 相似文献
898.
899.
900.
Uncertaintyandjointprobabilityofseaiceloads¥LiuDefu;YangYongchun;WangChaoandLiTongkui(OceanUniversityofQingdao,Qingdao266003,... 相似文献