Pore Pressure Transducers

The Druck PDCR-81 pore pressure transducer (PPT) is the most commonly used to measure pore water pressure in centrifuge models. It consists of an instrumented silicon diaphragm supported on an internal glass cylinder, which is connected to a (high air entry) porous filter by a steel outer casing (Take, 2003). The space between the porous filter and the diaphragm serves as a water reservoir. Changes of water pressure in the soil are transmitted to the water inside the reservoir, which tries to equalize the pressure of the soil leading to deformation of the diaphragm, which is measured as a change in voltage. The measured voltage is converted to water pressure applying a calibration factor.