桩身设计参数对大直径空心桩承载性状影响的仿真分析

Simulation Analysis of Pile Design Parameters' Influence on Bearing Performance of Large Diameter Hollow Pile

考虑桩周土体及接触的非线性,建立了空间轴对称有限元模型,通过与工程实测结果比较,证明模型合理;在此基础上系统分析了桩长、桩径对大直径空心桩承载性状的影响,结果表明:大直径空心桩存在临界桩长;空心桩从短桩变化到长桩,其承载特性从端承桩变化为端承摩擦桩;桩端沉降与桩顶沉降之比Se与长径比有关,其值在0.75 -0.99之间,说明大直径空心桩的沉降以桩端沉降为主。

Considering the non-linear of the soil and the contact between pile and soil, the spatial axi symmetry finite element model is established, and the simulation results agree with the actual data, which proves the model to be appropriate. Based on the model, the paper analyses the pile length and diameter＇ s influence on the bearing performance of the large diameter hollow pile, and the analysis shows that the pile has critical length. From short pile to long pile, the pile bearing performance will be changed from end resistance behavior to end resistance-friction behavior. The ratio of pile end settlement to pile top settlement Se is related to the ratio of pile＇ s length to diameter （L/D）, and changes from 0.75 to 0.99, which shows end settlement is dominant.