波浪作用下沙质海床上大直径圆筒结构动态响应的实验研究

通过物理模型实验,对沙质海床上沉入式大直径圆筒结构对波浪的动态响应进行了较系统的实验研究。实验中考虑了大直径圆筒、波浪和海床三者之间的耦合作用,并实时记录了大直径圆筒结构的动态响应。实验数据分析表明,大直径圆筒在波浪作用下的动态响应以大圆筒随波浪的前后摆动为主,其摆动轴心并不是固定不变的。最后通过回归分析给出了估算大直径圆筒摆动转角幅值的经验公式。     

沉入式大圆筒码头稳定性有限元强度折减法分析

由于作用荷载复杂,沉入式大圆筒码头结构设计计算需要考虑不利情况下的各种荷载组合,难以应用现有的有限元加载系数法进行稳定性分析。有限元强度折减法目前已广泛应用于土体边坡稳定性分析。沉入式大圆筒结构的抗滑、抗倾稳定性是靠地基土的嵌固作用来维持的,可通过弱化土体强度来实现对结构极限破坏状态的模拟。在此假设基础上,建立沉入式大圆筒码头稳定性分析的有限元强度折减法。结合某工程实例,利用有限元强度折减法分析沉入式大圆筒码头结构的稳定性。强度折减法只需对土体的强度进行弱化,操作方便,克服了加载系数法的缺点,适用于码头等作用荷载复杂的结构物稳定性分析。     

大圆筒结构在海上栈桥工程中的应用

大圆筒结构应用于威海华能金海湾国际饭店海上栈桥工程取得成功。重点论述大圆筒施工的工艺流程、方法以及注意事项,达到预期建设效果,获得相关结论。     

波浪作用下软基上沉入式大直径圆筒结构的变位计算模型

文章通过所建立的软粘土地基土体的循环累积变位分析模型，对大直径圆筒原型结构在波浪引起的水平向循环荷载作用下的基础稳定性进行研究，计算分析了简体随循环次数的变位状况和临界稳定状态时简体所受到的土压力分布以及临界稳定状态的判别参数c值。     

波浪对上部开孔带内柱的圆筒结构的绕射

应用透空壁内流体速度与两壁间压力差成正比的线性模型和特征函数展开方法,建立了外壁上部开孔并带有内柱的圆筒结构对波浪绕射的解析解.通过数值计算研究了外壁开孔率的大小、圆筒与内柱半径之比、筒内水深等因素对圆筒上总的波浪作用力和圆筒周围波浪高度的影响.经数值研究发现随着外壁开孔率的增大圆筒迎浪端的波浪高度和圆筒结构上总的波浪力明显减小,外壁孔隙特性G虚部的增加对波高和波浪力的衰减也有一定的影响;增加圆筒内部的水深可减小圆筒周围的波浪高度,降低圆筒结构上的总波浪力.     

软粘土中插入式大直径薄壁圆筒结构的一种极限状态分析模型

根据插入式大直径薄壁圆筒结构的工作特点建立了其合理的破坏机制，以此为基础建立了受横向荷载作用的插入式大直径薄壁圆筒结构的上限法极限分析模型，从中可以得到作用于插入式大直径薄壁圆筒结构上的横向极限荷载近似的上限解；并根据上限法模型计算结果，提出了计算受横向荷载作用的插入式大圆筒结构侧壁极限抗力的简化修正模型，利用此修正模型，基于极限平衡法，可以求解作用于插入式大直径薄壁圆筒结构上的横向极限荷载。     

随机波浪作用下座床式大直径薄壁圆筒防波堤的动力分析空间模型

随机波浪作用下座床式大直径薄壁圆筒防波堤的动力运动过程分为:摇摆、摇摆—小滑移运动和摇摆—大滑移运动三种运动模态,引入了控制侧向滑移的阻滑板—弹簧—阻尼器运动模型,建立了相应的动力分析空间模型。在大型有限元软件ANSYS中利用参数化设计语言APDL进行二次开发实现其空间模型,并把此空间模型计算结果与文献[1]中建立的平面模型计算结果比较,获得了一些有价值的结论,表明了本模型和方法对随机波浪荷载作用下大直径薄壁圆筒防波堤动力响应的数值模拟的可行性和有效性。     

斜向波浪作用下双层水平板式防波堤波浪荷载试验研究

In this study, systematic physical model tests were performed to investigate the wave forces on the twin-plate breakwater under irregular waves. Based on the experimental results, the effects of the relative plate width B/L,wave height Hs/D and incident angle θ0 on the wave forces were analyzed and discussed. The results showed that:(1) The envelopes of the total wave pressure were generally symmetrical along the direction of plate width under the incident angles(θ0) being 0°, 15°, 30°, 45° and 60°. In particular, the envelopes of wave pressure atθ0=30° were larger than all other cases.(2) The synchronous pressure distribution of the breakwater under oblique wave action was more complicated comparing to the normal incident waves.(3) Based on data analysis, an empirical formula was obtained to estimate the total vertical force of the twin-plate breakwater.This empirical formula can be a good reference for the design basis of engineering applications under specified wave conditions.     

软土地基中插入式大直径薄壁圆筒结构的一种简化数值计算方法

简述了对插入式大直径薄壁圆筒进行数值分析采用的力学机制，用弹簧元模拟薄壁圆筒与地基土体接触面间的连接所形成一种简化的数值计算模型，运用大型通用有限元软件ANSYS进行二次开发后对其进行数值计算与分析，比较了对筒内外淤泥粘土采用不同加固处理方法以及考虑相邻圆筒间采用不同边界约束条件时，对圆筒的应力和稳定性的影响。通过实例计算，验证了该数值模型的有效性与可行性，并得出一些有益结论。     

波浪荷载作用下近海风电单桩基础受力变形特性影响因素分析

为了对波浪荷载作用下近海风电大直径单桩基础受力变形特性的影响因素进行分析,以江苏省如东县某近海区域的水位地质条件为基础,运用有限元模拟软件 ABAQUS 进行数值模拟,对荷载大小、荷载位置、土体压缩模量、桩体自由度 影响因素展开分析。通过影响因素的不同量值,得出近海风电大直径单桩基础动载情况下受力变形特性的变化规律,从而为实际施工提供有价值的参考。     

An Approach to Stability Analysis of Embedded Large-Diameter Cylinder Quay

The large-diameter cylinder structure, which is made of large successive bottomless cylinders placed on foundation bed or partly driven into soil, is a recently developed retaining structure in China. It can be used in port, coastal and off-shore works. The method for stability analysis of the large-diameter cylinder structure, especially for stability analysis of the embedded large-diameter cylinder structure, is an important issue. In this paper, an idea is presented that is, em-bedded large-diameter cylinder quays can be divided into two types, i.e. the gravity wall type and the cylinder pile wall type. A method for stability analysis of the large-diameter cylinder quay of the cylinder pile wall type is developed and a method for stability analysis of the large-diameter cylinder quay of the gravity wall type is also proposed. The effect of sig-nificant parameters on the stability of the large-diameter cylinder quay of the cylinder pile wall type is investigated through numerical calculation.     

Coupled BEM-FEM Analysis of the Large-Diameter Cylinder Structure System

A method of coupled BEM-FEM analysis for the elastic spatial structure system is presented. It can be applied to the calculation of the stress and deformation of the large-diamater cylinder structure system and it is suitable for symmetric or non-symmetric structures under the distributed or concentrated load. Numerical examples show that the proposed method and computer program BEFEM are quite efficient in the analysis of the large-diameter cylinder structure problems in ocean engineering.     

极端波浪对海洋导管架平台的作用及其模型试验研究

通过极端波浪对海洋导管架平台作用力的模型试验,对极端波浪的作用进行了探讨。首先在常规波浪力计算公式的基础上,提出了极端波浪作用下的简易计算方法,并结合国外相应研究成果,提出了三个简易计算表达式;在对模型试验数据的分析基础上,给出了上述三个简易计算公式中的系数,从而得到极端波浪作用下的波浪力计算表达式。     

Undrained Dynamic Strength Behavior of Saturated Nanjing Fine Sand under Wave Load

Cyclic vertical-torsional coupling tests were performed on saturated Nanjing fine sand with a relative density of 50% using a hollow cylinder apparatus. The effect of complex initial stress conditions on undrained dynamic strength of saturated Nanjing fine sand was investigated. It is shown that the initial confining pressure, p₀, the initial stress ratio, R₀, and the initial angle of maximum principal stress direction, α₀, have great effects on the characteristics of the dynamic strength of Nanjing fine sand. The dynamic strength increases with p₀ and R₀, while it decreases with α₀. The effect of initial intermediate principal stress parameter b₀ on the dynamic strength is slight.     

Wave Uplift Forces on the Bottom of a Circular Cylinder

The analysis of the data of model tests of two large deep wharves and monographic experimental studies show that two aspects are to be improved so as to predict the wave uplift forces on the bottom of a circular cylinder. The first aspect is the uplift pressure distribution on the bottom, and the second is the correct determination of the phase for maximum horizontal wave forces. The second problem has been solved. Synthesizing the results of theoretical analysis and experiments, we suggest a diagram for the determination of the phase when the maximum horizontal wave force appears. On the basis-ef the diagram the simultaneous wave uplift forces can be obtained for the structural stability analysis.     

Analysis of Wave Height in Front of a Wave Absorbing Structure with Rubble Foundation

Wave absorbing structures have been widely applied in many countries. In the present paper, the wave heights in front of a vertical wave absorbing structure with rubble foundation as well as in the wave chamber of the structure are analysed using an approximative calculation method, and the dissipating effect of the structure is verified. On the basis of the results of regular waves, the relative wave heights of irregular waves in front of the wave absorbing structure as well as in the chamber have also been analysed.