低应变测桩的冲击脉冲及其谱分析

低应变测桩采用小锤敲击桩顶产生入射脉冲．检测时根据桩长、桩径等选择不同质量（铁锤、尼龙锤）和不同重量（轻、重）的小锤，激振出不同频率的入射脉冲，从而达到探测不同深度的桩身缺陷的目的。本文通过半正弦波模拟小锤的激振作用，采用积分变换等数学方法，求出小锤激振力的博氏变换模与频率的关系，绘制出关系图，从图中直观的反映了小锤激振能量随频率轴的分布规律。本次工作。直观地建立了小锤激振力与激振产生的应力波频率分布的对应关系，能够加深对动测理论的认识，同时也有助于理解动测曲线的滤波分析方法。

Impact Pulse of Low Strain Test Pile and Its Spectrum Analysis

In the low strain test for the pile,we use a light hammer to beat the head of the pile so as to produce the incident pulse.We also choose different quality for the iron hammer and nylon hammer and different weight for hammers(light or heavy) according to pile length and pile diameter.In this paper,based on simulating a light hammer of a half sinusoidal wave,we use mathematics methods such as integral transformations,etc.to explain the relation between Fourier transforming model and the frequency of the light hammer,and then draw out their relationship.From the drawing,we can directly find out the frequency distribution of the axle with the energy of stimulating the light hammer.What we have done can make us fully understand the theory of dynamic test,and meaningwhile can help us to understand the filtering method of the dynamic test curve.