浅谈大直径现浇混凝土薄壁筒桩土芯对竖向承载力的作用

Effect of soil plug on axial bearing capacity of large-diameter cast-in-situ tubular pile

对薄壁筒桩而言，正确认识内部土芯的形成及产生的闭塞效应是研究其荷载传递机理及准确计算承载力的重要组成部分，本文从土芯的形成出发初步探讨了影响土芯高度的诸多因素，研究表明，各因素中最重要的是土层分布情况，它不仅影响着土芯的高度，对土芯的闭塞效应也有极其重要的影响。目前我国筒桩设计计算尚无规范可循，是否考虑土芯的作用及如何考虑意见很不一致，因此基于土芯基本性状的研究很有必要，本文最后指出了目前土芯研究中存在的问题，供下一步深入研究参考。

The forming and the influences of soil plugging on large-diameter cast-in-situ tubular pile is the basis of its load transfer mechanism and axial bearing capacity estimation. This paper studies various effects on soil plugging and among these facts different spreading of soil layers has the predominant effect and influences not only the height of soil plug but also the effect of plugging. So far in our country there is no suitable code for this type of pile and meanwhile lots of argument against that if soil plugging should be considered and how to estimate. So the basic research of soil plug is essential. In the end of the paper the unsolved problems in this subject are put forward for further study.