多层根键根式桩水平承载力模型试验研究

Research on model test for horizontal bearing capacity of multi-layer root pile

根式桩是一种在桩身设置根键的新型变截面基础形式,相比等截面桩基础,根键的存在有效的增加了根式桩的水平方向极限承载力。本文基于模型试验方法,分别设计了一层、二层、五层根键根式桩和等截面桩在水平荷载下的对比试验,量测了桩身的位移、应变及桩周土压力,分析了不同桩型的水平承载力、桩身位移、桩身弯矩变化特点以及土体土压力变化情况。试验结果表明,单层根键根式桩比等截面桩水平承载力提高60%,同时随着根键层数的增加根式桩水平承载能力呈非线性增加。因此,合理增加根键层数可以有效提高根式桩的水平承载力,减小桩身位移和桩身弯矩。

The root piles is a new type of basic cross-section foundation with the root stubs set in the pile,compared with the same cross section pile foundation,the existence of root stubs increased the horizontal ultimate bearing capacity of the root pile effectively.This paper is based on model test method,the comparative tests of one-layer,two-layer and five-layer root pile and uniform cross section pile under horizontal load were designed,the displacement,strain and soil pressure around the pile were measured,the horizontal bearing capacity,displacement,bending moment and soil pressure of different types of piles were analyzed.The experimental results show that the horizontal bearing capacity of single-layer root-bonded pile is 60%higher than uniform cross section pile.Meanwhile,with the increase of the number of root stubs layers,the horizontal bearing capacity of root pile increases non-linearly.Therefore,reasonable increase in the number of root stubs layers can improve the horizontal bearing capacity of the root pile,and reduce the pile displacement and bending moment effectively.