Calibration and Bedding Material Study for Earth Pressure Cells.

摘要

Two basic methods of calibrating earth pressure cells are evaluated: (a) compressing earth pressure cells between pads of variousnsoft backing materials utilizing a rigid frame, hydraulic jack and load cell arrangement, and (b) hydrostatic pressurization. The mainnpurpose of this evaluation was to determine which method would result in a more consistent or reproducible calibration curve.nAlso investigated was the effect of various types of bedding materials on pressure cell performance. This was accomplished bynembedding pressure cells in cohesive or cohesionless soils contained in a laboratory-built pressure vessel, applying a hydrostaticnpressure to the soil surface, and then comparing cell responses to the hydrostatic calibration curve. Pressure cell responses werenanalyzed to determine the more desirable bedding material. Factors considered were reproducibility, cell response to actual appliednpressure, pressure vessel parameters, and depth of cover.