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对我国近年出现的几种新型码头结构的研究进行了综述和分析。其中，遮帘式板桩码头结构减小了作用于前板桩上的土压力，使板桩码头在大水深情况下得以应用；双排大管桩码头结构使大管桩较高的轴向承载力和抗弯强度得到充分发挥；架空直立式码头解决了内河大水位差情况下建造码头的难题；椭圆型沉箱的应用避免了采用2个圆沉箱产生前后不均匀沉降的技术难题。最后，对上述新型结构的应用进行了总结。 相似文献
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我国码头新结构型式综述 总被引：1，自引：0，他引：1
对我国近些年出现的几种新型码头结构进行了分析和综述。导管架码头结构型式是一种新型的结构型式,结构的整体刚度大、水平变位小、透空性好、波浪反射小,在开敞式环境下可适当降低码头面高程;椭圆沉箱墩式结构解决前后不均匀沉降的问题,提高了结构的整体稳定性;内河架空直立墩式结构对大水位差适应能力强,结构紧凑,对水流穿行影响小,装卸作业时泊稳条件好,是内河航道未来的发展方向。 相似文献
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由于前湾新港、能源交通及经济技术开发区的陆续兴建,黄岛已成为胶州湾畔举世瞩目的黄金海岸。港口水工建筑物工程量大是其主要特点,基础设施尚待开拓。现代海洋工程结构物广为采用的钢筋漏凝土沉箱,既是前湾码头的主要设计构件,也将是青岛市海岸工程良好的结构组成。因此,建议在黄岛筹建沉箱工厂,合理安排建港施工设施用地,为新港区的顺利建设和胶州湾的综合开发奠定好必需的工程基础。 相似文献
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由于开孔前墙和消浪室具有强扰动作用,所以开孔沉箱结构具有很好的消浪效果。本文通过日照港岚山港区码头开孔沉箱结构的物理模型试验,研究了沉箱不同开孔位置的消浪效果和水动力特征,分析了不同方案的反射系数和越浪量。结果表明：水位对反射系数的影响较大,开孔位置较高的方案,其消浪性能较好,且越浪量较小。选择反射系数和越浪量均较小的设计方案进行了水动力试验,结果表明：水平力最大时对应的浮托力约为最大浮托力的60%;浮托力最大时对应的水平力约为最大水平力的75%;波浪对开孔沉箱的作用主要集中于外壁迎浪侧,内部结构受到的波浪力很小;第二消浪室波浪力小于第一消浪室。 相似文献
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梳式沉箱翼缘板设计理论的研究 总被引：3，自引：0，他引：3
结合模型试验 ,分析了梳式沉箱翼缘板的静力和自振特性。研究了三种不同支承形式的翼缘板在最不利荷载下的内力分布 ,为梳式沉箱翼缘板的设计提供了依据 相似文献
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通过对沉箱结构在波浪作用下动力响应的模拟研究,探讨了一种有裙钢质沉箱的适用性,这种沉箱可利用负压效应来保持它自身的稳定。对于这种在沉箱底部和海底之间具有负压作用的沉箱,采用了“沉箱结构与海底相互作用分析法”在频率域中进行了动力响应数值计算。文中假定沉箱结构的分析模型是一个带有裙边的刚性棱柱体,在其底部设有若干个正方形的隔室（compartment）,负压就作用在每个隔室上;此外,还假定海底是一种液体饱和的多孔弹性体,其特性符合blot的波浪传播理论。沉箱裙边的长度以及作用在隔室上的负压对于沉箱动力响应的影响,也通过数值计算的方法进行了研究。其结论是：这种类型的沉箱应用于软质海底是相当有效的。如果海底上的渗透性差,只要为沉箱提供隔室,则它也会具有同样的优点。 相似文献
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针对深水平台吸力沉箱基础,讨论了与沉箱安装有关的分析方法及涉及的工程地质参数,分析了承受竖向拉拔荷载、倾斜与水平荷载作用的吸力沉箱极限承载力的分析方法及涉及的工程地质参数,对与吸力沉箱设计有关的其它问题也进行了分析.在此基础上,阐明了与吸力沉箱设计有关的工程场地调查内容及需要确定的工程地质参数.其目的是为开发深水平台吸... 相似文献
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黄岛二期油码头采用栈桥结构,水下桥墩19个巨型沉箱,在石臼港制作下水后拖运68海里(126公里)至黄岛安装取得成功,比在原地新建场制作缩短工期一年,节省直接费用二分之一。 相似文献
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The suction caisson (or called suction anchor) which is considered as a relatively new type of foundation of offshore structures, has been extensively studied and applied for offshore wind turbines and oil platforms. The installation of the suction caisson is of great importance in the design and construction because it can bring about several issues and further influence the performance of holding capacity in safety service. In this paper, large deformation finite element (FE) analyses are performed to model the installation of suction caisson (SC) by suction and jacking in normally consolidated clay. The penetration of the suction caisson is modeled using an axisymmetric FE approach with the help of the Arbitrary Lagrangian–Eulerian (ALE) formulation which can satisfactorily solve the large deformation problem. The undrained shear strength of the clay and elastic modulus are varied with depth of soil through the subroutine VUFIELD. The numerical results allow quantification of the penetration resistance and its dependence on the installation method. The centrifuge test and theoretical solution are used for the FE model validation. After the validation, the penetration resistance, the soil plug heave, and the caisson wall friction have been examined through the FE model. Based on the numerical results, it is shown that the ALE technique can simulate the entire suction caisson penetration without mesh distortion problem. The installation method can play an important role on the penetration resistance, namely, the suction installation reduces the penetration resistance significantly compared to the purely jacked installation. With a further study on the suction case, it is found that as the final applied suction pressure increases, the soil plug heave increases, while the penetration resistance reduces with increase of the final suction pressure. The effect of the friction of internal caisson walls has been also investigated and a conclusion is drawn that internal wall friction has a significant contribution to the penetration resistance and it can be implicitly represented by varying coefficient of internal wall friction. As for the penetration resistance, both jacked and suction installation have great dependency on the internal wall friction. 相似文献
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The multi-spring shear mechanism plastic model in this paper is defined in strain space to simulate pore pressure generation and development in sands under cyclic loading and undrained conditions,and the rotation of principal stresses can also be simulated by the model with cyclic behavior of anisotropic consolidated sands.Seismic residual deformations of typical caisson quay walls under different engineering situations are analyzed in detail by the plastic model,and then an index of liquefaction extent is applied to describe the regularity of seismic residual deformation of caisson quay wall top under different engineering situations.Some correlated prediction formulas are derived from the results of regression analysis between seismic residual deformation of quay wall top and extent of liquefaction in the relative safety backfill sand site.Finally,the rationality and the reliability of the prediction methods are validated by test results of a 120 g-centrifuge shaking table,and the comparisons show that some reliable seismic residual deformation of caisson quay can be predicted by appropriate prediction formulas and appropriate index of liquefaction extent. 相似文献
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Caisson foundations are often used in offshore engineering. However, for an optimum design understanding the failure process of a caisson during its installation and the subsequent external loadings is crucial. This paper focuses on the evolving failure of a caisson foundation in sand by advanced numerical modeling. A combined Lagrangian-smoothed particle hydrodynamics method is adopted to deal with the large deformation analysis. The method with parameters are first calibrated and validated by a simulation of cone penetration test in sand. The results of an experimental campaign of a caisson in the same sand are selected and validated for the numerical model. Then, more representative loading combinations are designated for numerical modeling of failure process and mode. Furthermore, three additional caisson dimensions D/d?=?0.5, 1.5, and 2.0 (changing the ratio of caisson diameter D to skirt length d while keeping the same soil-structure surface contact area) are simulated under six representative combined loading paths. Based on that, the influence of caisson dimension to the failure process and mode is investigated. All results are helpful to estimate all possible sliding surfaces under different monotonic combined loading paths for further limit analysis. 相似文献
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Shuwang Yan Jingjing Zhang Jian Chu Zhiliang Huo 《Marine Georesources & Geotechnology》2017,35(3):435-440
Concrete suction caissons have been successfully used as breakwaters or seawalls in recent years. The relative large wall thickness-to-diameter ratio of a concrete caisson can lead to the formation of a full soil heave plug that may cause difficulties in the installation of concrete caisson in clay. One way to overcome this limitation is to use a tampered tip for the caisson wall. An analytical method is proposed in this article to calculate the minimum suction pressure required to penetrate a caisson and the maximum allowable suction pressure that can be applied to avoid too much soil heave plug during the installation of the suction caisson. Four model tests were conducted in normally consolidated clay to study the installation process of a concrete suction caisson with tampered tip and to verify the proposed analytical method. The height of the soil heave plug in the caisson with a tampered tip is observed to be about half of that in the caisson with a flat tip. 相似文献
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Zhaoyu Wang 《Marine Georesources & Geotechnology》2013,31(1):52-62
This paper presents a numerical model of the seismic behavior for the embankment constructed on micropile composite foundation. The effect of micropiles on soil reinforcement under static and seismic loading was studied. Embankments on the untreated and treated soil by micropiles were numerically simulated using an axisymmetric elastoplastic large deformation finite-element analysis code. The displacement caused by embankment static loading and acceleration of the embankment caused by seismic loading were calculated and compared. It was shown that micropiles can greatly reduce the settlement of the embankment and mitigate seismic response of the embankment. The main objective of this paper is to present a numerical model and to investigate the seismic behavior of micropile foundations subjected to seismic loading. A series of numerical simulations and parametric studies are presented. 相似文献
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Response of skirted suction caissons to monotonic lateral loading in saturated medium sand 总被引：2，自引：1，他引：1
Monotonic lateral load model tests were carried out on steel skirted suction caissons embedded in the saturated medium sand to study the bearing capacity. A three-dimensional continuum finite element model was developed with Z_SOIL software. The numerical model was calibrated against experimental results. Soil deformation and earth pressures on skirted caissons were investigated by using the finite element model to extend the model tests. It shows that the ＂skirted＂ structure can significantly increase the lateral capacity and limit the deflection, especially suitable for offshore wind turbines, compared with regular suction caissons without the ＂skirted＂ at the same load level. In addition, appropriate determination of rotation centers plays a crucial role in calculating the lateral capacity by using the analytical method. It was also found that the rotation center is related to dimensions of skirted suction caissons and loading process, i.e. the rotation center moves upwards with the increase of the ＂skirted＂ width and length; moreover, the rotation center moves downwards with the increase of loading and keeps constant when all the sand along the caisson＇s wall yields. It is so complex that we cannot simply determine its position like the regular suction caisson commonly with a specified position to the length ratio of the caisson. 相似文献
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摇板式波浪能转换装置具有频率响应范围广、可靠性好、常规海况下转换效率高、建造成本低等优点。基于势流理论建立具有沉箱基础的摇板式波浪能装置水动力性能的解析解。将解析结果与文献中已有结果和边界元数值结果进行了对比,验证了解析解求解过程的正确性。通过算例分析,研究了波浪入射频率、沉箱基础高度、沉箱基础宽度、摇板位置、摇板厚度和摇板密度对装置能量俘获效率的影响。研究结果表明：采用合适高度的沉箱基础能显著提升装置性能;长波海况下,摇板铰接在沉箱基础背浪侧上表面时装置性能更佳,而短波海况下,摇板铰接在沉箱基础迎浪侧上表面更为合理;沉箱基础宽度的推荐值为0.5到1.0倍水深;适当减小摇板厚度能够提升装置性能;应优先选用密度较大的摇板。 相似文献
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The interaction between wave, seabed and marine structure is a vital issue in coastal engineering, as well as marine geotechnical engineering. However, most previous investigations have been focused on the wave forces acting on the structure from the aspect of hydrodynamics. In this study, we will examine the problem of wave-seabed-caisson interaction from the aspect of marine geotechnical engineering. Based on Biot's poro-elastic theory (Biot, M.A., 1941. General theory of three-dimensional consolidation. Journal of Applied Physics 12, 155–164), a two-dimensional finite element model is proposed to investigate the wave-induced soil response in the vicinity of a caisson. Based on the numerical model, the water wave driven pore pressure around a caisson will be examined through a parametric analysis. 相似文献
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复合加载条件下吸力式沉箱基础承载特性数值分析 总被引：2，自引：0，他引：2
吸力式沉箱基础的承载特性是海洋工程结构设施建造与设计中的一个关键问题。这种新型的深水海洋基础型式,通常承受竖向上拔荷载与水平荷载的共同作用,其工作性能与设计理论远远不能满足工程实践的需要。本文采用有限元分析方法对吸力式沉箱基础的极限承载特性进行数值计算。以大型通用有限元分析软件ABAQUS为平台,通过二次开发,数值实现了Swipe试验加载方法和固定位移比分析方法,针对不同的沉箱长径比、土的强度折减系数,探讨了沉箱基础在垂直上拔荷载和水平荷载单调联合作用下的极限承载力,通过对不同荷载组合的数值计算构造了复合加载条件下沉箱基础破坏包络面。 相似文献