中文摘要：

超声脉冲反射技术是指超声脉冲波垂直入射于不同介质表面，对反射脉冲波的到时、幅度等进行成像。基于超声脉冲反射原理，由传递矩阵法数值模拟了水泥环声阻抗的差异对接收到的超声脉冲反射波波形的影响，在此基础上又研究了水泥环声阻抗对回波能量和反射波波谱的影响。数值研究结果表明，水泥环声阻抗大时的反射波后续波列的幅度小、波列的拖尾比较短，相应的频谱曲线中的谱陷较小且比较圆润；反之，水泥环声阻抗小时的反射波后续波列幅度大，拖尾长，其频谱曲线中的谱陷比较大且尖锐。

英文摘要：

Ultrasonic pulse reflection technique is referred to the imaging ot time and amplitude ot the reflected pulse wave which is caused by the incidence of the ultrasonic pulse to the different mediums surface. Based on the principle of ultrasonic pulse-echo method and the propagator matrix method, simulated is the influence of the difference in acoustic impedance cement sheath on the received ultrasonic pulse wave. In addition, we also focus on the impact of the acoustic im- pedance of cement sheath on the echo energy and reflection spectrum. The calculation shows that, when the acoustic impedance increases, the amplitude of the follow-up wave decreases and the waveform is with a shorter tail. Accordingly, the spectrum is smaller and smoother. Otherwise, the amplitude follow-up wave is larger with a longer tail and the spectrum is larger and sharper when the acoustic impedance reduces.