桩底土与桩相互作用的模型试验研究

Model Experimental Study of Pile-soil Interraction at the Bottem of Pile

选用黄河砂子、南疆盐渍土作为桩底土进行桩土相互作用的模型试验,应用回传射线矩阵法对不同压实状态下桩底土的刚度系数和阻尼系数进行拟合,建立桩顶反射速度波幅与入射速度波幅比随时间、阻尼系数和刚度系数的变化关系式.试验结果表明:土越密实,桩底刚度系数就越大,实测桩顶速度波时程曲线就越往下倾斜;桩底土层的分层层数和分层厚度对反射波产生很大影响.

Huanghe River sand and saline soil at the south of Xinjiang were used as pile-bottom-soil, and the interaction of pile-bottom-soil and pile were researched with laboratory model experiments. The reverberation-ray matrix method was applied to fit stiffness and damping coefficients of pile-bottom-soil in different compaction conditions. The relationship between measured incident and reflected velocity wave amplitude ratios and time,damping coefficient, and stiffness coefficient is established. The experimental results show that the denser soil is,the greater stiffness coefficients are, and the more downward the measured velocity time-history curves at top of pile biases. Laminar numbers and thickness have greater effect on the reflected wave.