含水含孔试样破坏的波速及功率谱密度特征

为研究不同含水率含孔试样破坏过程中的超声波特征，开展了不同含水率条件下的含孔试样单轴压缩试验，并采用RSM-SY7超声波仪测定了压缩过程中的波速，得到了不同含水率含孔试样的透射波波形。结果表明:试样初始波速均值随着含水率上升而逐步下降;在含孔试样破坏过程中，波速变化呈现出稳定—轻微降低—迅速降低3个阶段;稳定和迅速降低阶段所经过的时长随含水率降低而增大;轻微降低阶段所经过的时长随着含水率的降低而减少;在试样破坏的同时，功率谱密度也产生衰减;其衰减程度受到含水率的影响，含水率越高各频率的功率谱密度衰减越均衡，谱峰衰减程度越小，不同时刻的衰减程度越相似。

Characteristics of wave velocity and power spectral density of hole-containing specimens under water conditions

In order to study the ultrasonic characteristics of the pore samples with different water contents,the uniaxial compression test of the pore samples under different water conditions was carried out,and the wave velocity during compression was measured by RSM-SY7 ultrasonic system.Transmission waveform of a sample containing pores with different water contents was obtained.The results show that the average initial wave velocity of the specimens decreases gradually with the increase of water content.During the destruction of the hole-containing specimens,the change of wave velocity has three stages including stable stage,slightly decreasing stage and rapidly decreasing stage.The duration of the stable and rapidly decreasing stages increases with the water content decrease;the duration of the slight decrease stage decreases with the water content decrease.The power spectral density also decays as the specimen breaks.The degree of attenuation is affected by the water content.The higher the water content,the more balanced attenuation of the power spectral density in each frequency,the smaller the attenuation at the peak,and the more similar attenuation at different times.