福州港松下港区牛头湾作业区航道平面方案研究

福州港松下港区牛头湾作业区7万吨级1#、2#和3#泊位分别于2007年、2009年及2012年建成投产至今,每年11月至翌年3月期间受风浪影响,大型船舶靠、离码头难度大、系泊码头作业泊稳条件差。为保障船舶靠、离泊和系泊作业安全,业主单位拟建设防波堤二期工程,与已建防波堤一期工程形成环抱式防波堤。本文根据防波堤布置初步方案,对港区进港航道进行平面布置比选,并提出防波堤、航道布置优化方案,节省了工程投资。经波浪数值模拟和潮流数值模拟验证,航道布置方案可满足船舶安全通航要求,优化后防波堤仍能有效减小码头前沿波高,满足码头泊稳条件和实际作业要求。     

新型卷波弧形台阶防浪堤

本文表述既能抗御台风暴潮又能回卷波浪，集海塘、挡潮、交通、旅游多种功能于一体的两级台阶弧形组合防浪堤的设计基本点及其运用特性。     

Geosynthetic-sheet pile reinforced foundation for mitigation of earthquake and tsunami induced damage of breakwater

Earthquake and tsunami impose great threats on the stability of a breakwater. Foundation of the breakwater is weakened by these forces, and it may result in collapse of the breakwater. Lateral flow of seabed soils take place beneath the breakwater, and excess pore water pressure is generated in the foundation by an earthquake that precedes tsunami. These factors may lead to excessive settlement and horizontal displacement of the breakwater. Tsunami introduces additional instability to the deformed breakwater. Due to water level difference between seaside and harborside of the breakwater during a tsunami, seepage occurs through its foundation, and it may cause pipping of seabed soils. Tsunami induced scouring of mound is also a big problem for the stability of the breakwater foundation. Finally, these result in failure of the breakwater foundation. Due to failure of its foundation, the breakwater may collapse and cannot block the tsunami. It results in entering of the tsunami in coastal areas. In order to make a breakwater resilient against earthquake and tsunami induced damage, reinforcing countermeasures were developed for foundation of a breakwater. Geogrid, gabions and sheet piles were used for reinforcing a foundation model. The effectiveness of the model is evaluated through physical modeling for mitigating the earthquake and tsunami induced damage. Shaking table tests were performed to determine the effectiveness of the reinforced model under different earthquake loadings. Tsunami overflow test was conducted on the same deformed model in order to see the effects of tsunami on the model. Comparisons were made between the unreinforced and reinforced foundations, and it was observed during the tests that the reinforced foundation performed well in reducing the damage of the breakwater brought by the earthquake and tsunami. Overall, this study is useful for practice engineering, and the reinforced foundation model can be adopted for designing a breakwater foundation to reduce damage triggered by an earthquake and tsunami in the future.     

Stability of caisson-type breakwater foundation under tsunami-induced seepage

A tsunami-induced difference between the water levels of the seaward and the landward sides of breakwaters generates one-way seepage in the rubble foundation under the breakwaters. Such seepage may decrease the bearing capacity of the rubble foundation, trigger the piping and/or boiling of the foundation, and cause the scouring of the sandy seabed. In this paper, we describe the stability of a breakwater foundation under the action of seepage based on the results of model tests and FEM analyses. The main feature of our study is the application of the centrifuge technique to such composite hydrodynamic and geotechnical problems. The centrifuge technique can be used to produce high-water pressure and ground stress corresponding to those of prototype-scale breakwaters. The experimental results show that seepage-induced scouring and boiling occur, and that the seepage force decreases the bearing capacity of the rubble foundation. The results of the numerical analyses also reveal the effect of the reduction in bearing capacity in the presence of seepage.     

新型梳式防波堤

梳式防波堤是一种新型直立防波堤,国内外属首创。它具有消浪、轻型、便于透流等特点。示范工程——国家重点大连港大窑湾一期岛堤工程采用了这种结构,水平向波浪力消减了27％,节省工程投资24.5％(6435万元)。本文介绍了消浪结构防波堤国外发展概况、梳式防波堤开发和示范工程实施情况,给出了水平波浪力折减系数和波浪反射系数经验公式,为结构断面的初步确定提供了依据。     

防浪板对两栖车航行特性影响的研究

基于实验结果,文中采用数值模拟方法研究了防浪板对两栖车航行阻力特性的影响.结合k-ω湍流模型与多相流模型,对不加装防浪板、加装防浪板以及加装新型防浪板的两栖车的水上航行性能进行了数值模拟分析.研究结果表明,均相流模型与k-ω湍流模型相结合,能够很好地模拟两栖车水上航行阻力特性;防浪板能够有效地降低两栖车所受阻力,合理的防浪板结构最大减阻效率可达40%;并且,防浪板能够有效提高两栖车航行时的稳定性.     

Physical model studies on damage and stability analysis of breakwaters armoured with geotextile sand containers

Harnessing the advantages of geotextile sand containers (GSCs), numerous submerged breakwaters and shoreline protection structures have been constructed worldwide. But an emerged breakwater structure with geotextile armour units, capable of replacing the conventional structures, is rarely discussed. A 1:30 scaled physical experimentation is chosen as a preliminary investigation to test the feasibility of using GSCs as breakwater armour units. Structural design is evolved based on a comprehensive literature survey. The paper focuses on the stability parameters and damage characteristics of the proposed structure. Four different configurations are subjected to waves, confining to Mangaluru's wave parameters. Effect of armour unit size and sand fill ratio on the stability of the structure is analysed and it is concluded that changing sand fill ratio from 80% to 100% shot up the structural stability to a maximum of 14%. Increasing bag size also resulted in the increased stability up to 8%. Experiments revealed that the best performing configuration could withstand wave heights up to 2.7 m. Stability curves for all tested configurations are discussed and can serve as an effective guideline for designing GSC breakwaters.     

防波堤抛石基床的水下爆夯方法

爆炸夯实法处理深水抛石基床是近几年发展起来的一项新技术。本文介绍温岭石塘中心渔港１＃防波堤大面积水下爆夯工程，总结了海上防波堤抛石基床爆炸夯实法施工方法和工艺技术，提出了相应的施工工序和参数。通过对防波堤的沉移观测和分析，阐明了爆炸夯实法处理海堤深水抛石基床的可行性和优越性。     

Stability of composite-type breakwaters reinforced by rubble embankment

Details of the failure characteristics of composite-type breakwaters reinforced by rubble have not been clarified, including the prehension of some failure modes and the conditions that cause each mode. In this study, details of the failure characteristics and a performance assessment method were studied using two approaches, namely, centrifuge model tests and a circular slip analysis. The model tests showed that sliding failure could occur when the friction between the mound and the caisson was low, the caisson was wide, and the reinforcing embankment was high and/or wide. In contrary cases, bearing capacity failure was liable to occur. Basically, the larger the reinforcing embankment size, the greater the strength and stiffness. The performance assessment using a circular slip analysis and considering failure modes was verified through discussions. The analysis resulted in the underestimation of the stability of the reinforced breakwaters when the rubble was angular. However, the caisson moved to a certain degree even with a relatively lower load and the displacement reached that which is allowable by the structure. Consequently, a circular slip analysis was deemed suitable for evaluating the performance of reinforced breakwaters.