Abstract: This article describes the detection principles,main characteristics of surface wave exploration technology and its application in the inspection of subgrade grouting in karst area in HeFu passenger rail line,along with validation of the data from water injection and core sampling.The results indicate that surface wave exploration is a simple,fast and cost effective way to provide results with highresolution visual presentation.

Key words: Rayleigh Surface Waves, Karst Grouting, Detection Results