基于变分原理的静压沉桩挤土效应理论解答研究

静压法施工工艺近年来得到广泛使用。但静压桩是一种挤土桩,挤土作用将对桩基础本身和周围环境产生一系列影响,引发很多工程问题。通过综合考虑桩长有限、地面自由、终孔孔壁形状、孔壁位移边界条件以及土体材料非线性,应用变分原理推导沉桩挤土位移、应变和应力场解答,并应用经典土压力理论、小孔扩张理论和Ansys计算结果对理论推导结果进行验证。研究结果对静压桩的施工、相应防护措施的选择和设计有较大的指导作用。

Theoretical analysis of soil squeezing effect due to jacked piles based on variation principle

The construction of jacked piles is a widely-used technique of pile engineering at present.The job practices have many merits,but many theoretical and practical problems still need to be solved.A model of soil squeezing due to jacked piles is established considering the effect of the final shape and the displacement boundary of pile wall,the stress free ground surface,the finity of pile length and the non-linearity of soil materials.The soil displacement,strain and stress solutions are obtained based on the variation principle.Finally,comparisons are made to prove the reasonability of the solutions using the passive soil pressure theory,the classical CEM results and the ANSYS analysis results.