夯实水泥土桩桩身压缩量对承载特性的影响

针对夯实水泥土桩的施工方法，在桩身埋设特制的应变传感器，测定桩身应变。基于试验测试数据，探讨桩身压缩量的计算方法，分析桩身压缩变形的分布规律及其对桩侧摩阻力的影响，并探讨不同桩长、不同水泥掺入比情况下，夯实水泥土桩桩身压缩量及其对承载特性的影响。研究表明，（1）对夯实水泥土桩，桩身压缩主要集中在桩身上部8 d（d为桩径）范围内，且变形速率变化较大，桩身压缩在桩顶位移中占比达80%以上；（2）桩身轴向荷载传递、桩侧摩阻力分布主要发生在此范围内；（3）桩身侧摩阻力分布非常不均匀，上部发挥较为充分，而下部发挥较少；（4）在工程常用水泥掺入比下，桩长大于12 d后，桩长径比和水泥掺入比的变化对桩承载特性影响不显著。

Influence of pile shaft compression on bearing properties of rammed soil-cement pile

Aiming at special method of installation of rammed soil-cement piles,laying special strain sensor and then the pile shaft can be measured.Based on test data of pile shaft compressions,the computation method of shaft compression is studied;and the distribution of pile shaft compression,and its influence on shaft resistance are analyzed.The shaft compression and its influence on bearing properties in different lengths and different cement contents of rammed soil-cement pile are discussed.Research results show that(1) the pile shaft compression is mainly distributed in upper range of pile length about 8 pile diameters;and the varying gradient is larger;and pile shaft compression the displacement of pile tip;(2) the axial load transfer,distribution of shaft resistance occurred mainly within this range;(3) the shaft friction distribution is uneven;and it plays more fully in upper part of pile and less in lower part of pile;(4) under cement mixing ratio within the common project and the length-diameter ratio>12,the change of length-diameter ratio and cement mixing ratio is not significant effect on load-bearing characteristics of pile.