advanced Continuous Surface
Wave Testing

Advanced Continuous Surface Wave (ACSW) testing uses surface geophones to measure the speed at which surface Rayleigh waves generated by a vibratory ‘shaker’ travel through the ground over a range of frequencies. Using advanced software ACSW provides a representative shear wave velocity (Vs) profile, which can be used for site assessment or to provide highly accurate ground stiffness values
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CSW Site Assesment

Specialist ACSW testing & Analysis


The velocity of surface waves generated is directly related to ground stiffness. The speed of shorter wavelengths is influenced by the stiffness of shallower layers and the longer wavelengths by the stiffness of deeper layers, so measuring the velocity over a range of frequencies means a stiffness depth profile can be produced. GSS Advanced Continuous Surface Wave (ACSW) system is controlled and evaluated by GSS’s bespoke C-DAS data acquisition and analysis software which provides easy-to-understand outputs.  Importantly, as part of the analysis process a shear wave velocity (Vs) profile is generated which can be used for seismic design or site assessment.




Key benefits of ACSW Testing


Stiffness & Vs profile to typical 20 to 30ft depth or more


Measurements at known small-strain stiffness – so stiffness can be adjusted for design strains


A bulk stiffness/Vs value over a 10ft length of soil



About 30mins per test, including setup and packing up


Costs equivalent to Plate Load Test

Low risk

Non-intrusive, so no need for boreholes or lab time


A bright new wave in geotechnics.