Since it is known that the progress of rock weathering leadto the decrease of its seismic Velocity, the seismic velocities of rock are used to decide the weathered grades of the rocks, and we can determine whether or not a weathered rock can be excavated with ripper.
This method is based on a correlation between seismie velocities and rippability, Rippable and nonrippable seismic Velocities are determined for the different types of rock.