吹填淤泥下桶式基础结构土压力及位移分析

Analysis of soil pressure and displacement on bucket-based structure under reclamation silt

桶式基础结构是一种能较好地适应水深、浪大、地基软弱等恶劣环境的新型水工结构,其稳定性主要靠桶体结构自重和桶体与土体共同作用抵抗外荷载.土压力的大小及其分布规律是桶式基础驳岸结构计算的首要问题.结合实际工程,建立了桶式基础结构与土体相互作用的三维非线性有限元数值模型,分析了在不同厚度吹填淤泥工况下桶体基础结构上的土压力大小及竖向分布规律,并与基于土的极限平衡条件下的Rankine土压力理论的计算结果进行了比较分析;修正了传统主、被动土压力的计算公式,并对结构在不同厚度的吹填淤泥下的位移进行分析.结果表明,吹填淤泥下结构土压力与传统土压力公式计算误差为25%,结构整体向吹填淤泥侧倾斜,最大转角是无吹填淤泥工况的1.24倍,最大沉降值是无吹填淤泥工况的1.16倍.研究为新型桶式基础驳岸结构的稳定性验算提供了参考依据.

The bucket-based structure is a new type of hydraulic structure that can better adapt to hostile environments such as deeper water,big waves,and silt soils of low bearing capacity.Its stability depends mainly on the deadweight of barrel structure and interaction of the barrel and earth to resist external loads.Therefore,the level and distribution of soil pressure are primary factors in the calculation of bucket foundation revetment structure. In view of practical engineering,a 3D elasto-plastic finite element model is established to analyze interaction between the structure and the soil.Analyses of the soil pressure and the barrel’s vertical and circular distributions are performed with different thickness of reclamation silt.It is compared with the calculation results of the soil’s limit equilibrium using the Rankine’s soil pressure theory.The traditional formula for active and passive soil pressure is revised,and displacement of the structure with different thickness of reclamation silt is also analyzed.Calculation error in soil pressure between the traditional and the proposed methods is 25%,and the bucket-based structure as a whole tilts toward the land reclamation silt side.The maximum angle is 1.24 times larger than that without reclamation silt,and the maximum subsidence is 1.16 times.