破碎波循环冲击下软基上圆矩形新型吸力式防波堤的运动形态及稳定性研究

The suction breakwater, which has a wide application prospect, can be suitable for soft foundation and severe wave conditions. Acording to the main problems of the bucket foundation breakwater in construction and the use process, this project intends to put forward a new type of circular and rectangular suction breakwater, which is without complex splicing, has an optimized structural style and better stability. It is urgent to study the motion morphology and stability of thin-walled structure inserted in soft foundation such as the new type of circular and rectangular suction breakwater on soft foundation under cycle impact of breaking wave. How to reasonably simulate the influence of the cyclic breaking wave for the mechanical properties of soft foundation, the dynamic damage of soil-structure interface, and the method to efficiently calculate structural stability are the key scientific problems. A method of combining theoretical analysis, laboratory test and numerical simulation will be used to carry out studies for the project. A dynamic constitutive model based on effective stress which can consider the effect of cyclic impact under breaking wave on mechanical characteristics of saturated soft clay, and the effect of cyclic impact under breaking wave on contact area will be established. At the same time, it is necessary to establish dynamic stability, quasi static stability and simplify stability methods for the new type of circular and rectangular suction breakwater, which can quantitatively calculate its stability under cyclic impact of breaking wave. It is also important to study the movement form and the supporting mechanism of the new type of circular and rectangular suction breakwater. The research results will be of significance in academia as well as application of engineering, and also be of significance of reference to the stability studies on large-scale coastal and ocean structures inserted in soft foundation.

新型吸力式防波堤能够适用于软基和恶劣波浪条件，具有广泛的应用前景。针对箱筒型基础新型吸力式防波堤在建造和使用过程中的问题，本项目拟提出圆矩形新型吸力式防波堤，该结构无复杂拼接，结构更优化，稳定性更好。目前亟待研究圆矩形新型吸力式防波堤等薄壁沉入式结构在破碎波循环冲击下的运动形态和稳定性。如何合理模拟破碎波循环冲击作用对软土力学特性的影响、对软土与结构接触面的动力损伤，以及如何高效计算结构稳定性是其中的关键科学问题。本项目拟采用理论分析、室内试验、数值模拟相结合的方法，建立可考虑破碎波循环冲击作用对饱和软粘土力学特性影响的有效应力动本构模型，同时考虑破碎波循环冲击对接触面的损伤，建立可定量计算破碎波循环冲击下圆矩形新型吸力式防波堤稳定性的动力、拟静力和实用简化分析方法，探究其运动形态和承载机理，研究成果具有重要的学术与工程应用价值,对软基上大型海岸和海洋结构物的稳定性研究具有普遍借鉴意义。

新型吸力式防波堤能够适用于软基和恶劣波浪条件，具有广泛的应用前景。针对箱筒型基础新型吸力式防波堤在建造和使用过程中的问题，本项目提出了圆矩形新型吸力式防波堤，该结构无复杂拼接，结构更优化，稳定性更好。本项目采用理论分析、室内试验、数值模拟相结合的方法，建立了可考虑破碎波循环冲击作用对饱和软粘土力学特性影响的有效应力动本构模型，同时考虑破碎波循环冲击对接触面的损伤，建立了可定量计算破碎波循环冲击下圆矩形新型吸力式防波堤稳定性的动力、拟静力和实用简化分析方法，探究了其运动形态和承载机理。当软土地基的剪切强度均一时，吸力式基础的各单向承载力基本不受内隔板的影响，当软土地基的剪切强度不均一时，在深径比较小时，内隔板可明显提高桶形基础承受力矩和水平荷载的能力（尤其是力矩承载力），但对竖向承载力提高不大。高灵敏度，低延展性，弱率效应，低刚度与强度比的软土上的圆矩形新型吸力式防波堤在破碎波循环作用后的承载力降低的大。软土强度弱化应该在圆矩形新型吸力式防波堤设计中考虑，因为它对基础在遭受循环破碎波后的短期承载力有明显影响。全面考虑静偏应力、破坏振次和破坏应变标准的循环强度模型可方便研究不同破坏应变标准和破坏振次对结构循环承载力破坏面的影响。研究成果具有重要的学术与工程应用价值，对软基上大型海岸和海洋结构物的稳定性研究具有普遍借鉴意义。