（中国建筑科学研究院， 北京 100013）

［摘要］竖向力作用下单桩会发生沉降，贯入变形是沉降量的主要组成部分。一直以来，贯入变形无法确切地归为弹性变形或者塑性变形，在理论上这也不便于用弹性解计算桩基础沉降。基于工程桩静载荷试验研究了单桩荷载传递机制，发现在工作荷载作用下，当桩端是平底形且持力层相对较好时，贯入变形呈现小变形特征； 桩端阻力和贯入变形为线弹性关系，不存在桩端刺入持力层的情况； 从理论层面研究了考虑桩径影响的Mindlin位移解，证明贯入变形是局部弹性压缩变形，不是塑性变形，这为利用弹性解研究工作荷载作用下桩基础沉降提供了积极的支撑。

［关键词］贯入变形； 局部压缩； 弹性变形； Mindlin位移解

中图分类号：TU443文献标识码：A文章编号：1002-848X(2020)21-0102-04

Discussion on mechanism of single pile penetration deformation

QIU Mingbing, GAO Wensheng, LIU Jinli, REN Xinjian

(China Academy of Building Research, Beijing 100013, China)

Abstract:The single pile is subjected to vertical force to produce settlement, and penetration deformation is the main component. It has always been a fuzzy zone whether the penetration deformation is elastic or plastic, which creates theoretical obstacles for calculating the settlement of pile foundations with elastic solutions. The load transfer mechanism of a single pile based on the static load test of an engineering pile was studied. It is found that under working loads, when the pile end is flat-bottomed and the bearing layer is relatively good, the penetration deformation presents small deformation characteristics; the end resistance and penetration deformation are linear elastic relationships, and there is no situation that the pile end penetrates the bearing layer; theoretically, the Mindlin displacement solution considering the influence of the pile diameter was studied, and it is proved that the penetration deformation is local elastic compression rather than plastic deformation. This provides active support for studying the settlement of pile foundation under working loads by using elastic solution.

Keywords:penetration deformation; local compression; elastic deformation; Mindlin displacement solution

作者简介：邱明兵，硕士，高级工程师，Email: qiumb@sina.com。