深厚软土地基条件下格形钢板桩结构承载机理与计算方法研究

Deep-seated soft soil subgrades are widely distributed in the coastal areas of China, such as the Pearl River Estuary, the Yangtze River Estuary and Bohai Bay, etc., which brings great difficulties to the design of port and coastal structures. Cellular steel sheet pile structure is suitable for the deep-seated soft soil subgrades and is used in Japan and European countries. However, in the present uses of the cellular steel sheet pile structures, the penetrating depth of steel sheet piles is shallow. In the condition of deep-seated soft soil subgrades, the interaction between the cellular steel sheet pile structure and soil is more complicated, the bearing mechanism of the cellular steel sheet pile structure is not clear and the design calculation methods are not trustworthy, which places restrictions on the practical application of the cellular steel sheet pile structure. In this project, the finite element model for the mechanical property analysis of cellular steel sheet pile structure will be established considering the flexibility of steel sheet pile, the locking hinge between steel sheet piles, the soil plasticity of subgrade, strong nonlinear interactions between the cellular steel sheet pile structure and soil. The bearing mechanism, the failure modes, the deformation and stress distribution of the cellular steel sheet pile structure will be investigated, and the calculation methods of shear deformation resistance, the stability against sliding and overturning, bearing capacity of foundation, sheet pile locking force will be set up to settle the key sciences and the calculation methods of the cellular steel sheet pile structure in practical application.

在我国珠江口、长江口和渤海湾等海岸地区,广泛分布着深厚软弱土地基，给港口与海岸工程建筑物设计带来巨大困难。格形钢板桩结构由若干单块钢板桩在现场通过锁口连接拼装成圆形、椭圆形或多边形的格体并打入地基后形成，是适用于软弱土地基条件的水工建筑物。格形钢板桩结构在日本和欧洲等国家得到较多应用,但板桩入土深度较浅，地基为砂性土等较好土层。深厚软弱土地基条件下格形钢板桩结构与土相互作用问题复杂，承载机理尚不清楚，缺乏可靠的设计与计算方法，限制了格形钢板桩结构的应用。本项目建立考虑钢板桩柔性、板桩锁口铰接、土体塑性和循环承载特性、结构与土体强非线性相互作用特性的格型钢板桩结构力学分析的有限元数值模型，研究深厚软土地基条件下格型钢板桩结构的承载机理、破坏模式、位移和应力分布特性，建立结构抗剪切变形、抗滑抗倾稳定性、地基承载力、板桩锁口拉力等计算方法，解决格形钢板桩结构工程应用中的关键科学和计算方法问题。

在我国社会、经济发展最活跃的渤海湾沿岸、连云港以南的苏北沿海、长江口、杭州湾、闽江口、韩江口、珠江口和海南岛西北部等沿海地区广泛分布着软弱土地基，给港口与海岸工程建筑物设计带来巨大困难。格形钢板桩结构由若干单块钢板桩在现场通过锁口连接拼装成圆形、椭圆形或多边形的格体并打入地基后形成，是适用于软弱土地基条件的水工建筑物。格形钢板桩结构在日本和欧洲等国家得到较多应用，但板桩入土深度较浅，地基为砂性土等较好土层。深厚软弱土地基条件下格形钢板桩结构与土相互作用问题复杂，承载机理尚不清楚，缺乏可靠的设计与计算方法，限制了格形钢板桩结构的应用。本项目研究考虑钢板桩柔性、板桩锁口铰接、土体塑性和循环承载特性、结构与土体强非线性相互作用特性的格型钢板桩结构力学分析的合理有限元数值模型，以及深厚软土地基条件下格型钢板桩结构的承载机理、破坏模式、位移和应力分布特性，建立结构抗剪切变形、抗滑抗倾稳定性、地基承载力、板桩锁口拉力等计算方法，解决了格形钢板桩结构工程应用中的关键科学和计算方法问题。发表标注论文30篇学术，其中SCI收录论文6篇、EI收录论文16篇；获中国航海科技进步一等奖1项，天津市科技进步二等奖1项；培养博士生2名，硕士生4名。