载荷作用下EPS混凝土中弹性波传播特性研究

Elastic wave propagation in EPS concrete under loadings

应用EPS混凝土模拟含缺陷的岩石材料。对EPS粒径分别为1 mm、2 mm和3 mm的三种EPS混凝土试样进行了载荷作用下不同频率的弹性波传播实验研究。采用单一频率脉冲叠合的方法来精确确定材料的波速,结果表明:EPS混凝土试件的p波波速随载荷增加的初始压密实阶段有较明显的增大趋势,当试件相对密实,波速增加则不很明显;s波波速随载荷增加有一定程度增加,但幅度比p波波速增加得小得多;应用一种相对波速的方法,即将波速与当前载荷下材料的声波速度进行对比,可以较好地分析波速与载荷及频率的关系;最后对波速与载荷和频率的关系进行了理论模拟分析。此研究对于应用弹性波进行材料和结构的无损检测等技术方面有参考意义。

EPS concrete was taken as a model material for rock with defects in meso scale. Series of tests of elastic wave propagation were conducted to investigate three kinds of EPS concrete samples with EPS particle diameters of 1mm,2mm and 3mm under different frequencies and axial loads. A so-called pulse echo overlap method（ PEO） was employed to accurately determine the wave speed of samples under single frequency. Results showed that p wave speed of EPS concrete samples increases obviously with increase in loads in the initial densification stage,and then it increases slightly when sample were compressed densely; their s wave speed increases with increase in loads,but their amplitude increases much smaller than those of p wave. A relative wave speed method to compare the wave speed with the sound speed of the material under the current loads was proposed to analyze the relationships between wave speed and loads and frequencies.The relationships between wave speed and loads and frequencies were analyzed with theoretical simulation. The study results were meaningful and helpful for non-destructive checking of materials and structures with application of elastic wares.