About the stress-state measurements in soil models.

This paper reports about a research which deals with the construction and the calibration of different types of pressure cells to be used in measuring the state of stress induced inside a soil model. The knowledge of the stress-state distributions is of great relevance in such instances as the soil-foundation interaction analyses or the interpretation of calibration chambers tests. Five different types of cells have been designed and tested. Their overall dimensions have been limited at minimum values yet maintaining the capability of the celI to provide readings integrated from a reasonable sensing surface with respect to the sand grains' mean size. The pressure cells were calibrated either in a fluid and in the same soil which will be used later to build the laboratory models. Numerical simulations have then been executed using a FEM modeler in order to check the basic hypotheses and some of the soil cell interaction mechanisms.