Abstract

The cemented soil–pipe pile is an expanded pile that is composed of a high-strength, precast, prestressed pipe pile core and an expanded zone of cemented soil. To investigate the shear behaviours of the cemented soil–pipe pile interface, a series of large-scale direct shear tests on the cemented soil–concrete interface under various cemented soil strengths and different normal stresses were conducted in this research. The results revealed that the shear stress increased approximately linearly with the increase of shear displacement. When the bond limit was reached, the interface slid and the shear stress decreased sharply to the residual stress, after which it remained almost constant. The shear stress increased with the increase of the cemented soil strength and normal stress, while the peak stress was found to be relatively less affected by normal stress. The residual stress was found to be less affected by the cemented soil strength, while it increased dramatically with the increase of normal stress. Based on the test results, the shear process of the cemented soil–concrete interface can be summarised as the bond failure stage and the friction slip stage.

摘要

水泥土管桩是一种膨胀桩，由高强度，预制，预应力管桩芯和水泥土的扩展区域组成。为了研究水泥土-管桩界面的剪切特性，本研究对水泥土-混凝土界面在各种水泥土强度和不同法向应力下进行了一系列的大规模直接剪切试验。结果表明，剪切应力随着剪切位移的增加而线性增加。当达到粘结极限时，界面滑动，剪切应力急剧下降至残余应力，此后几乎保持恒定。剪切应力随着水泥土强度和正应力的增加而增加，而峰值应力受正应力的影响相对较小。发现残余应力受水泥土强度的影响较小，而残余应力则随法向应力的增加而急剧增加。根据测试结果，水泥土-混凝土界面的剪切过程可以概括为粘结破坏阶段和摩擦滑动阶段。