界面形貌对混凝土工程层状介质中弹性波传播的影响

摘要

利用有限元研究混凝土-岩土层状介质中弹性波的传播问题,对混凝土-岩土界面粗糙度进行量化,建立了界面曲率分别为0、0.25、0.50、0.75、1.00五组数值模拟模型.通过ANSYS瞬态动力分析得到弹性波在五组模型中传播的时域信号,然后对其进行快速傅里叶变换和短时傅里叶变换分别得到频域信号和时频信号,最后结合弹性波波形及能量、频率以及表征反射效应的时频分析评价层状介质界面粗糙度对弹性波传播的影响.结果表明:反射信号接收点时频关系中共振周期随表征界面粗糙度的界面曲率增加呈递增趋势,共振频率呈递减趋势,当界面粗糙程度超出一定值时,趋势相反;通过快速傅里叶变换得到的频谱关系中共振频率与入射信号频率差值随界面曲率增加逐渐缩小.%Studying the propagation of elastic wave in Concrete-Rock layered media by using finite element method.Five models that curvature of the interface were 0,0.25,0.50,0.75,1.00 were established to quantify the interfacial roughness.The time-domain signal of elastic wave propagation in five models was calculated by ANSYS transient dynamic analysis,according the method of FFT and STFT to obtain the frequency-domain and time-frequency domain,and comprehensive evaluation of the impact of interface roughness to elastic wave propagation on layered medium by the elastic wave shape and energy , frequency, and time -frequency analysis. The results demonstrate that resonance cycle in time-frequency showed an increasing trend when the interface roughness increased,and resonance frequency showed an decreasing trend,as the roughness beyond special value,the trend is opposite;The difference between resonance frequency that is transformed from FFT and incoming signal frequency reduced gradual y with curvature increased.