（温州市建筑设计研究院，325000）

［提要］通过五根直径相同、桩长相近、位于同一场地的超长大直径钻孔灌注桩在拔力与压力作用下的对比试验，分析抗拔桩与抗压桩在变形性状和荷载传递机理的相同性和差异性。试验结果表明，对于超长大直径钻孔灌注桩，桩侧摩阻力总是上部土体首先发挥，而后逐渐传递给下部土体，桩侧摩阻力均存在强化效应和退化效应，桩沉降（上拔）以桩身压缩（伸长）为主；抗拔桩桩顶Q-s曲线呈陡降型，抗压桩桩顶Q-s曲线呈缓变型，桩承受竖向上拔力所表现出来的刚度明显小于承受竖向压力所表现出来的刚度。

［关键词］超长大直径钻孔灌注桩；抗拔；抗压；对比试验

Comparative Test Research on Resistant Extraction and Pressure of Super-long and Large-diameter Bored Piles/Chen Yuelin (Wenzhou Architectural Design and Research Institute, Wenzhou 325000, China)

Abstract:Based on comparative test on resistant extraction and pressure of five super-long and large-diameter bored piles with same diameter and similar length in the same ground, the community and difference of distortion behavior and load transmission property are analyzed. The test results show that lateral friction on the top pile reaches the limiting strength earlier than that on the bottom, and the lateral friction is reinforced or weakened with load developing, and the set

tlement(ascending) is produced mainly by pile compressing(extending).Q-s curve is post nonlinear for resistant extraction and adagio nonlinear for resistant pressure, and pile rigidity is clearly less for resistant extraction than resistant pressure.

Keywords:large-diameter and super-long bored piles; resistant extraction; resistant pressure; comparative test