膨胀混凝土灌注桩的受力分析

膨胀混凝土灌注桩是一种近年来发展起来的新型成桩方式。本文首先利用弹性理论否定了其承载力提高是单纯由于摩擦力提高的简单解释，然后以试验数据为基础，从三个方面分析了承载力提高的原因：蠕变、固结过程的缩短能加速桩周土承载力的提高；按极限荷载的定义，桩长伸长能充分发挥桩身承载力和桩底承载力；桩端土强度、刚度的提高对桩侧阻力在桩端有明显的增强效应，并对膨胀混凝土灌注桩的设计和施工提出了建议。

Analysis of Bearing Power of Expansive Concrete Bottling Pile

Expansive concrete bottling pile, a new kind of bottling pile developed recently in civil engineering, is more and more popular. The explanation, which shows the pile's bearing power increase was simply because of friction-rise between pile and soils around it, is denied after careful investigation. Then, three causes for enhancement are discussed on the basis of experiment. The first is that soil's bearing power around pile can be made the best use because of creep and consolidation quickly ended. The second is, according to concept of ultimate bearing capacity, that pile shaft and base resistance can be made full use owing to pile's lengthening. And the third is that pile shaft resistance around pile's underside end is reinforced remarkably because of increase of strength and rigidity of soils under the pile.