GDS manufactures Geophysics testing equipment for assessment of shear wave velocity. This is typically used in site investigations for foundation engineering design and settlement prediction. It allows fast, non-invasive testing for all soil types, including residual soils and fractured soft rock. Geophysics testing is also suited for the rapid sub-grade evaluation for roads, tracks and runways. The list below shows the different tests, gives an explanation of each test and link through to the apparatus that can perform these tests.
Multi-stage Testing

The procedure for conventional triaxial tests requires three separate soil specimens to be sheared to failure under different confining pressures so that Mohr-Coulomb failure envelope can be determined and soil shear strength parameters can be obtained. An alternative procedure is the multi-stage triaxial compression test, which requires only one soil specimen to be tested at three stages of shearing with different confining pressures.

There main advantages of multi stage soil testing is the requirement for fewer soil specimens, as well as reduced testing time.  The advantage of performing the test with 3 separate samples is that if one of the samples is unsatisfactory (perhaps due to sample disturbance for example) then it is likely to be noticed when the Mohr circles are plotted, whereas this could remain unnoticed in the multi stage test. Please note: Some apparatus may require additional components or software modules to perform certain tests.