This CDSS device is capable of conducting cyclic (up to 5 Hz) or monotonic direct simple shear tests on both saturated and unsaturated soil samples with a diameter of 63.5 mm and a height of up to 40 mm. The sample is enclosed in a rubber membrane and confined by the stacking of Teflon-coated rings. The test can be carried out under either drained or undrained conditions. Additionally, the device has been modified to conduct tests on samples with a constant suction of up to approximately 90 kPa. This is achieved by applying negative pressure to the water phase in the sample through a 100 kPa air-entry ceramic disk at the base of the sample.
