Contribution to Measuring Suction and Interstitial Pressure in Unsaturated Soils.

摘要

This study analyzes the geotechnical possibilities afforded by the Peltier-effect psychrometer for measuring the humidity potential of soil, which is to say the suction. After a description of the principal existing apparatus, some original equations are developed which make it possible to tie suction, s, to the signal supplied by the psychrometer, on the basis of its geometric features. With the help of these equations, analysis is performed on the effects of establishing equilibrium, temperature, pressure, and the presence of a soil sample as well as calibration. These considerations then make it possible to compare the psychrometer with apparatus in current use -- suction plate, tensiometer, pressure chamber and vacuum dryer -- and to show its advantages. Finally, after describing the experimental device, calibration results are given which show the validity of the equations set up; also given are suction measurements taken on a silt, which show the validity of the psychrometric method.