Earth Pressure Measurements Using Tactile Pressure Sensors in a Saturated Sand During Static and Dynamic Centrifuge Testing

The performance of tactile pressure sensors used in centrifuge testing involving pressure measurements of laterally-spreading soils against a large, rigid, foundation element is evaluated. The tactile pressure sensor measurements were consistent with hydrostatic pressures measured by pressure transducers under most testing conditions, and agreed with at-rest geostatic pressures provided that the measurements were made against a rigid surface (i.e., no relative soil-structure movement). However, measured pressures decreased substantially under some conditions when shearing forces were transmitted to the pressure sensors. Dynamic pressures (minima and maxima pressure spikes) measured by the tactile pressure sensors differed from pressures measured by pore pressure transducers and, when uncorrected, they were considered unreliable. A dynamic pressure correction was developed to address this issue. Lastly, a comprehensive verification testing program was recommended for each unique centrifuge test configuration to improve interpretation of pressure sensor output.