This paper used vertical acoustic reflection method to detect the quality of Liaofang Reservoir\'s dike cutoff wall,and processed original data in instantaneous spectral method.

As one of the methods,the sound wave reflection method expatiates the application value and significance of HSP sound wave test in excavation of tunnels from various aspects such as sound wave reflection principle,working conditions and practical application in projects,etc.

This paper presents briefly the analyzer LX Ⅱ for quality detection of rock and soil engineering and its functions and describes the principle of test,data analysis and processing and methods of inversion of means for detecting in-situ elastic wave of rockmass such as vertical reflection method, elastic wave CT method and instantaneous Rayleigh wave method.