Resonant Column Apparatus (Stokoe Type)

The B-Check is a pre-test to check that the specimen is sufficiently saturated by measuring the Skempton pore water pressure parameter B. The cell pressure is increased to the specified value whilst the back pressure remains on hold volume (i.e. the undrained state). The system compares the change in pore pressure (Δu) caused by the increase in cell pressure (Δσ3). The value of B is calculated as Δu/Δσ3.  If your GDS triaxial testing system has a cell pressure controller and a pore pressure transducer, then the B-check is automated within the GDSLAB software. Please note: Some apparatus may require additional components or software modules to perform certain tests.

Consolidation simply applies a constant cell and back pressure to the sample whilst monitoring the volume change within the sample. Please note: Some apparatus may require additional components or software modules to perform certain tests.

The constant rate of flow test simply maintains a constant base pressure whilst applying a constant flow through the top of the specimen. A maximum hydraulic gradient can be set which will pause the rate of flow if the pressure differential between the top and the base of the sample gets too large.  Please note: Some apparatus may require additional components or software modules to perform certain tests.

Some geotechnical applications require the continuous flow of fluid, either under pressure control or via a rate of fluid flow.  GDS manufacture an Infinite Volume Controller (IVC). By connecting 2 GDS pressure/volume controllers in parallel, the IVC system automatically switches between them when they run out of volume thus providing a seamless supply of pressure with unlimited volume capacity.  The IVC can be used with any 2 pressure controllers from the GDS range, i.e. advanced, standard or enterprise. Please note: Some apparatus may require additional components or software modules to perform certain tests.

The damping ratio is a measure of describing how oscillations in a system die down after a disturbance i.e. how the shear waves generated in the sample die down after a test is complete. This test can be carried out in torsion or flexure through the resonant column.

The damping ratio is a measure of describing how oscillations in a system die down after a disturbance i.e. how the shear waves generated in the sample die down after a test is complete. This test can be carried out in torsion or flexure through the resonant column.

Determination of the maximum (i.e., very small strain) shear modulus of a specimen. Please note: Some apparatus may require additional components or software modules to perform certain tests.

Saturation ramp allows you to independently increase or decrease the Cell Pressure and the Back Pressure. The saturation ramp is used to steadily change the pressures in the system either keeping a constant effective stress or change to a desired effective stress.

Is the deformation of an object through bending, curving, or flexing.  This non-standard can be performed in the GDS resonant column apparatus as it has the ability in the software to reverse the polarity in one of the coils and switch 2 of the other coils to be open circuit, thus resonating the soil sample in flexure (bending).

The standard test performed in a resonant column cell is resonance in torsion.  By establishing the resonant frequency in torsion of a soil sample, the soil shear modulus can be calculated.

The damping ratio is a measure of describing how oscillations in a system die down after a disturbance i.e. how the shear waves generated in the sample die down after a test is complete. This test can be carried out in torsion or flexure through the resonant column. Please note: Some apparatus may require additional components or software modules to perform certain tests.