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What is ACSW?
Introduction to ACSW
Advanced Continuous Surface Wave (ACSW) testing is a fast, non-intrusive means of obtaining an in-situ ground stiffness profile in a construction environment.
The velocity of surface waves is a function of the ground stiffness, and the wavelength of the surface wave determines its depth of penetration. By measuring surface wave velocities over a range of frequencies (and consequently a range of wavelengths), a stiffness profile of the ground can be obtained.
The depth to which data can be obtained using ACSW is dependent on the shaker source and ground conditions, but 30 to 45-feet depths are typical - and in stiffer materials depths of up to 60-feet can be achieved, using readily portable seismic sources.
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ACSW Outputs
Advanced Continuous Surface Wave (ACSW) testing is a fast, non-intrusive means of obtaining an in-situ ground stiffness profile in a construction environment.
The velocity of surface waves is a function of the ground stiffness, and the wavelength of the surface wave determines its depth of penetration. By measuring surface wave velocities over a range of frequencies (and consequently a range of wavelengths), a stiffness profile of the ground can be obtained.
The depth to which data can be obtained using ACSW is dependent on the shaker source and ground conditions, but 30 to 45-feet depths are typical - and in stiffer materials depths of up to 60-feet can be achieved, using readily portable seismic sources.
SoilSafe - Your Partner in ACSW Testing
Advanced Continuous Surface Wave (ACSW) testing is a fast, non-intrusive means of obtaining an in-situ ground stiffness profile in a construction environment.
The velocity of surface waves is a function of the ground stiffness, and the wavelength of the surface wave determines its depth of penetration. By measuring surface wave velocities over a range of frequencies (and consequently a range of wavelengths), a stiffness profile of the ground can be obtained.
The depth to which data can be obtained using ACSW is dependent on the shaker source and ground conditions, but 30 to 45-feet depths are typical - and in stiffer materials depths of up to 60-feet can be achieved, using readily portable seismic sources.
Our Expertise
SoilSafe undertakes and regularly publishes research on ACSW stiffness profiling.
SoilSafe provides an updated range of guidance documents on the practical ground engineering applications for ACSW testing.
Using ACSW Data
Advantages of ACSW Testing
01
Speed
Where access is straightforward, 20 tests per shift or more are normally possible, allowing significant coverage of sites to assess stiffness variation or addressing time limited working (e.g. railroad or highway work). Simple inversion ground stiffness profiles can be generated on site immediately following each test for rapid site assessment.
02
Accuracy
ACSW testing does not involve the usual compromise between cost and accuracy. There is a wealth of published information to demonstrate ACSW data is as accurate as the most expensive stiffness testing, and often an order of magnitude more accurate than empirical methods.
03
Low Cost
Each ACSW test costs less than an in-situ CBR Test – but can provide accurate stiffness profiles to up to 60-feet depth, depending on ground conditions. Combined with speed of testing, this means ACSW is a highly economical means of site characterisation for design, control testing or validation.
04
Ease of use
ACSW test results are graphical and easy to interpret. Layered profiles provided following advanced inversion include a numerical stiffness value for each layer which can be input directly into calculations or models without the need for uncertain empirical relationships.
05
Low Risk
ACSW does not require excavations, boreholes or the use of heavy equipment. SoilSafe’s system also does not require manual handling of heavy equipment and the system also offers low noise and disturbance compared to intrusive investigations.
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