基于回传射线矩阵法获得桩顶作用半个正弦波脉冲时成层土中部分埋入黏弹性桩桩顶处速度导纳,利用Fourier逆变换与卷积定理获得瞬态半正弦激振力作用下桩顶处时域速度响应。比较均匀地基部分埋入桩受桩身材料阻尼与桩侧土体阻尼作用的桩顶速度响应,分析软(硬)夹层厚度、夹层土土性参数、桩底土土性参数变化对桩顶速度导纳及反射波影响。结果表明,桩身材料阻尼对桩顶速度导纳及反射信号均有衰减作用,且会使桩底反射波发生弥散现象;桩侧、桩底土体刚度变化会使速度导纳低频段曲线产生偏移量;桩侧、桩底土体阻尼变化对桩顶速度导纳及反射波较二者刚度变化影响更大。
Abstract
Based on the method of reverberation-ray matrix, the velocity admittance responses curves of a viscous-elastic pile partially embedded in layered soil are derived, caused by a vertical unit impulse at the top of the pile。 The time-domain velocity responses of the pile, subjected to a semi-sine impulse at the top, are obtained through the inverse Fourier transform and the convolution theorem。 It is compared that the velocity response of pile top about embedded partially in homogeneous soil is produced by pile damping and damping surrounding the pile。 The influences of soft(or hard) interlayer thickness, interlayer soil parameters and soil parameters of pile end on velocity admittance and reflection wave of pile top are analyzed in detail。 The results show that: the pile damping make velocity admittance and reflecting signals of pile top attenuate, and pile damping causes the dispersion phenomenon of reflecting wave at the bottom of pile。 The low frequency curves of velocity admittance generate offset, because the soil stiffness of surrounding the pile and pile end have a change。 But the damping changes of surrounding the pile and pile end have a bigger effect on velocity admittance and reflecting wave of pile top than the soil stiffness changes of surrounding the pile and pile end。
关键词
回传射线矩阵法 /
成层土 /
部分埋入黏弹性桩 /
瞬态波动 /
速度导纳
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Key words
reverberation-ray matrix method /
layered soil /
viscous-elastic pile embedded partially in soil /
transient wave /
velocity admittance
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脚注
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