应力波在深层搅拌桩中传播特性的数值模拟

通过对应力波在深层搅拌桩中传播过程的数值模拟,分析了不同脉冲荷载、接收点位置、缺陷类型、桩周土体性质对应力波传播的影响,得到不同条件下反射波的信号特征。结果表明:采用橡胶锤激振能够获得较好的信号,接收点位于距桩心0.70R附近处效果最佳;不同缺陷具有不同的反射波特征,具体表现在反射波的相位和振幅上;同时,随着缺陷的增大,桩底反射波的振幅呈减弱趋势。桩周土成层时与单一土层相比,应力波的传播速度明显减小。

Numerical Simulation of Propagation Features of Stress Wave in Deep Mixing Piles

Through the numerical simulation of stress wave propagation in the deep mixing piles,the impact of stress wave propagation is analyzed on different pulse load,defect type,receiving point and pile material properties,and the signal characteristics of reflected waves are obtained under different conditions.The results show that: the good signal can be got with excitation of rubber hammer and the effect is the best when the receiving point is located at 0.70R from pile centre.The different defects cause different abnormal signals of reflected wave,which manifested in the phase and amplitude.Meanwhile,the amplitude of the pile’s bottom reflection show decreasing trends with the increase of the defects.The velocity of stress wave reduce significantly when the pile layered in multi-layer soils.