USE OF ELECTRICAL PRESSURE TRANSDUCERS TO MEASURE SOIL PRESSURE.

The application of electrical transducers to measure soil pressures against planar surfaces is described, with emphasis on the determination of the coefficient of earth pressure at rest K sub o for cohesive soils. Data are presented on the value of K sub o for a saturated silty clay Boston Blue Clay as a function of consolidation pressure, maximum past pressure and overconsolidation ratio. These data were obtained via a square fixed ring oedometer which had a Dynisco pressure transducer screwed into one side of the cell. Although the observed values of K sub o appear reasonable and are consistant with other published data, the degree of accuracy is unknown. Attempts to calibrate the transducer by comparing measured versus applied average pressures on a planar surface are described. These results indicated that the measured pressure is directly related to the applied soil pressure. Author