利用桩顶加速度分析打桩时桩端土的静阻力

Determining Static Resistance of Pile Toe During Driving with Acceleration of Pile Top

本文利用应力波理论建立了计算打桩时桩端土静阻力的公式。在该公式中，桩端土的静阻力可以直接从桩顶的加速度信号中获得的桩顶回弹和冲击力持续时间计算得到，并且计算结果和土阻尼无关。同时分别将本文方法和静力触探、击数法及ＣＡＳＥ法作了比较。结果表明，按本文方法计算的静阻力几乎和锤的落高及桩垫刚度无关。本文方法可以用于预估单桩承载力及控制桩的打入深度。

A method based on the stress-wave theory to estimate the static resistance at pile toe during pile driving has been developed. In this method, the static resistance at pile toe can be calculated directly with the rebound at pile top and impulse duration from the acceleration signal at pile top. Compared with CPT, CASE method and blowcount test, the result is more reliable and almost independent of soil-damping, ram-drop-height and cushion-stiffness. The method can be used to estimate the bearing capacity of single pile and to control the depth of pile to be drived.