Abstract: The cross hole elastic wave CT method was used to deteet the cloud map of the rock and soilmass at the bottom of the pile in a karst development area. The geological conditions at the bottom of thepile such as the rock and the soil mass of the karst cave were ascertained and evaluated. The practiceshows that cross hole elastic wave C'T method has the characteristies of data visualization, and can bepopularized and applied in the exploration of underground buried objects such as karst caves.

Key words: karst investigation, the bearing stratum of the pile foundation, cross hole elastic wave CT method