刚性支承潜浮隧道

在宽深的水域建造永久性跨海通道,始终是世界各国桥隧建设中的一大难题。刚性支承潜浮隧道方案为解决这一难题提供了一个值得关注的结构模式。刚性支承潜浮隧道采用双向受力、组合式结构的设计理念,用横向顶出式抗拔钢桩做隧道管的固定支承件,使单车道工程造价降低到不及桥梁和普通隧道的一半;而且,没有土方量,没有污染,使工程变得简单易行。以琼州海峡为例,介绍刚性支承潜浮隧道的基本结构、受力原理、施工方法、安全措施和一些关键难题的解决方法,为建造永久性跨海通道提供借鉴和参考。     

浮运转体法架设钢桁梁施工技术

在青阜铁路增建二线茨淮新河特大桥钢桁梁架设施工中,根据现场施工条件,合理利用六七式铁路舟桥器材、六四式铁路军用梁等战备器材,拼组成浮运船,使钢桁梁在岸边预拼装,然后利用浮体转体法、浮运法将钢桁梁整体架设到位,大大降低了施工难度,减少了占用航道时间,创造了良好的经济效益,可供同类施工参考.     

深水平台上层模块海上吊装多浮体响应分析

海上吊装操作是平台海上安装作业中的重要一步,深海吊装操作面临着恶劣海况的考验。对于海上吊装操作过程中的多浮体相互干扰运动,采用了时域数值纽马克方法求解,选定JONSWAP风浪谱进行随机海况模拟。重点研究了不同浪向组合对多浮体运动响应的影响,提出安全作业浪向。在安全海况下进行了不同风速影响的研究,提出安全作业的风速范围。在安全作业海况下进行了吊装操作模拟,证实吊装操作能平稳进行,对海上吊装操作安全顺利进行具有重要意义。     

浅吃水单柱式浮式风机动力学特性仿真研究

本文采用FAST软件对一种浅吃水单柱式浮式风机系统的动力学特性进行了研究.这一浮式风机适用于能源成本相对合理、水深为150 m的海域.本文首先讨论了这一浮式风机系统和OC3-Hywind系统在动力学特性方面的差异,然后研究了风尤其是湍流风对系统动力学特性的影响,最后对这一系统在多种载荷状况下的动力学行为进行了详尽的分析.研究结果表明:湍流风会在系统固有频率附近引起显著的激励;纵荡和纵摇运动取决于风轮推力,它们通过风轮推力和相对风速之间的联系建立起耦合关系;Spar平台的艏摇运动主要取决于平台横摇时由风轮推力引起的艏摇力矩.     

On the dispersion relation of hydroelastic waves in a plate

This paper deals with the dispersion relation of hydroelastic waves in pontoon-type very large floating structures (VLFS) using a simple beam modeling, where the term hydroelastic waves means propagation of deflection vibrations in VLFS. The purpose of this paper is to show the properties of the hydroelastic waves. The dispersion relation of hydroelastic waves propagating in an infinite plate floating on the water is derived based on the linear water wave theory. The effects of the water depth and of the bending rigidity of the floating plate on the wavelength, phase velocity, and group velocity of the hydroelastic waves are shown theoretically or numerically. Then, the dispersion relation of hydroelastic waves in a finite plate floating on shallow water is investigated. It is shown that the wavelength or the phase velocity of the hydroelastic waves varies with the location in the plate. Received for publication on April 7, 1999; accepted on Aug. 20, 1999     

Experimental study on the wave-induced dynamic response and hydrodynamic characteristics of a submerged floating tunnel with elastically truncated boundary condition

Hydrodynamic load and motion response are the first considerations in the structural design of a submerged floating tunnel (SFT). Currently, most of the relevant studies have been based on a two-dimensional model test with a fixed or fully free boundary condition, which inhibits a deep investigation of the hydrodynamic characteristics with an elastic constraint. As a result, a series of difficulties exist in the structural design and analysis of an SFT. In this study, an SFT model with a one-degree-of-freedom vertical elastically truncated boundary condition was established to investigate the motion response and hydrodynamic characteristics of the tube under the wave action. The effect of several typical hydrodynamic parameters, such as the buoyancy-weight ratio, γ, the relative frequency, f/f_N, the Keulegan–Carpenter (KC) number, the reduced velocity, U_r, the Reynolds number, Re, and the generalized Ursell_s number, on the motion characteristics of the tube, were selectively analyzed, and the reverse feedback mechanism from the tube's motion response to the hydrodynamic loads was confirmed. Finally, the critical hydrodynamic parameters corresponding to the maximum motion response at different values of γ were obtained, and a formula for calculating the hydrodynamic load parameters of the SFT in the motion state was established. The main conclusions of this study are as follows: (i) Under the wave action, the motion of the SFT shows an apparent nonlinearity, which is mainly caused by the intensive interaction between the tube and its surrounding water particles, as well as the nonlinearity of the wave. (ii) The relative displacement of the tube first increases and then decreases with increasing values of f/f_N, U_r, KC number, Re, and the generalized Ursell_s number. (iii) γ is inversely proportional to the maximum relative displacement of the tube and the wave force on the tube in its motion direction. (iv) Under the motion boundary condition (as opposed to the fixed boundary condition), the peak frequency of the wave force on the SFT in its motion direction decreases and approaches the natural vibration frequency of the tube, whereas the wave force perpendicular to the motion direction increases. When the incident wave frequency is close to the natural vibration frequency of the tube, the tube resonates easily, leading to an increased wave force in the motion direction. (v) If the velocity in the Morison equation is substituted by the water particle velocity measured when the tube is at its equilibrium position, the inertia coefficient in the motion direction of the tube is linearly related to its displacement, whereas that in the direction perpendicular to the motion direction is logarithmically related to its displacement.     

基于有限元法的船用浮筏隔振系统仿真计算

采用有限元法对某船用浮筏隔振装置的静态特性、固有振动特性、隔振效果和抗冲击性能进行了数值分析，并对浮筏隔振装置的隔振效果进行了测试，浮筏隔振装置的加速度振级落差实验台架测试结果超过35dB，测试结果表明文中的数值分析方法是可行的．     

浅水沉管船的锚泊定位系统设计

浅水锚泊系统的设计增加了诸多挑战,恶劣的环境使船舶具有较大的低频漂移运动,同时锚泊系统需要有足够的恢复力特性。文章针对深中通道沉管船,基于三维势流理论,在时域下对安装船和沉管系统进行分析,设计出合适的锚泊系统,并验证了锚泊系统设计的安全性。同时为以后类似系统的设计提供借鉴。     

盾构隧道壁后注浆中“定时浆”试验研究

我国盾构隧道广泛使用凝结时间较长的单液浆,但由于注入后不能及时凝结常常引发管片上浮、浆液流失等工程问题。针对这些问题提出“定时浆”的概念。通过在单液硬性浆中添加氯化铝溶液与水玻璃,基于浆液的胶结时间、流动度、28 d强度等指标研究了“定时浆”的配方。结果表明： 1）通过先加入氯化铝溶液再加入水玻璃的方法,可以实现浆液“定时”凝结; 2）在硬性浆中掺加0.50%~0.75%的氯化铝溶液、1.00%~1.25%的水玻璃,可以达到良好的定时效果; 3）通过简单的注浆设备改造可以形成“双液单注”的定时注浆工艺。     

Silas和Densitune系统在航道工程中的应用

以连云港港15万t级航道疏浚工程施T期浮泥观测为例,介绍Densitune音叉振动密度仪、Silas适航水深测量系统和悬移质取样器的特性,并根据实测的浮泥层厚度及其分布情况,剖析Silas和Densitune系统在实际工程应用中遇到的问题,供丁程设计和运营管理参考.