单桩沉降遮拦效应的研究

针对桩基沉降中普遍存在的遮拦现象，提出了用剪切移法分析单桩沉降遮效应的方法，并推导了相应的理论公式；结合上海的地质情况对单桩的遮拦效应进行了分析，结果表明：桩对土体深度方向的差异沉降具有明显的遮拦作用，桩刚度对遮拦效果影响较大，遮拦桩不宜作用柔性桩；遮拦桩轴向刚度接近于受荷桩轴向刚度时，已获得理想的遮拦效果，再增大遮拦的刚度意义不大。

Study of Sheltering Effects of Single Pile from Settlements

Aiming at the sheltering phenomena in settlements of pile foundations ,this paper provides an analyzing method of sheltering effects of single pile from settlement by integral method, and a series of corresponding theoretical formula. Furthermore, the paper gives an analysis of sheltering effect of single pile based on geography in Shanghai. It is obtained that single pile has obvious sheltering effects from differential settlements in soil at deep direction ,and sheltering effects of pile are distinctly affected by its axial stiffness; sheltering pile shouldn't be a flexible one; a sound effect can be achieved when the stiffness of sheltering pile is close to that of loaded pile ,and it is insignificant to enhance unduly the stiffness of sheltering pile.