Continuous Surface Wave (CSW)

The continuous surface wave system is a computer controlled ground stiffness profiling method developed by GDS Instruments Ltd in the United Kingdom. A surface vibrating unit generates ground waves as the computer steps the vibrator though a range of frequencies. A row of geophones measure the Rayleigh waves generated, which are dispersed through the ground to a depth of about one wavelength.

The geophone configuration allows the Rayleigh wave velocity to be calculated. From this, the shear wave velocity and the shear modulus can be calculated. The shear modulus is converted to Young's Modulus, which is plotted against depth. Black Geotechnical have the latest inversion software developed in South Korea to maximise the accuracy of the data.