刚性桩复合地基渗流固结性能分析

基于饱和砂井渗流固结理论，推导了综合考虑褥垫层、桩、土模量的刚性桩复合地基渗流固结解析解。在ABAQUS中使用Modified Cam-clay模型和孔压单元模拟桩间土体，建立单桩复合地基有限元分析模型。计算结果与某高层结构刚性桩复合地基静载试验吻合较好，验证分析模型的有效性。使用该分析模型，研究褥垫层厚度、模量，桩长对刚性桩复合地基受力及固结变形的影响。结果表明：刚性桩复合地基固结速度远大于天然地基，固结速度随褥垫层模量增大而增大，随井径比减小而增大；结构施工过程中，地基固结沉降已基本完成；褥垫层模量的增大可减小刚性桩复合地基固结沉降，但褥垫层厚度及排水土层厚度的增加都会加大固结沉降。

Analysis of seepage and consolidation properties of rigid-pile composite foundation

A consolidation theoretical solution of rigid-pile composite foundation, which takes the modulus of cushion, pile and soil in consideration, was derived on the basis of saturated sand drain well consolidation theory. The FEA model of a single pile composite foundation was established in ABAQUS adopting the Modified Cam-clay constitutive model and pore element to simulate the soil between piles. The calculation fit well with the experimental results, which proved the validity of numerical simulation. The influences of thickness and modulus of cushion, the length of pile on the mechanical and consolidation settlement of rigid-pile composite foundation were further analyzed. The results show that: the consolidation rate of rigid-pile composite foundation is quite faster than natural foundation; the consolidation rate is faster with larger cushion modulus and minor drain diameter ratio; the consolidation is almost finished during the construction process; the increase of cushion modulus leads to decrease of consolidation settlement, but the increase of thickness of cushion and drainage soil layer leads to the opposite effect.