UNA PROCEDURA AUTOMATIZZATA PER LA DETERMINAZIONE DELLE CARATTERISTICHE MICROSTRUTTURALI DELLE SABBIE MEDIANTE ANALISI DI IMMAGINI DI SEZIONI SOTTILI

It is well known that macroscopic mechanical behaviour of sand - and in general,of granular soils - originates from their microstructural characteristics such as, for example,the coordination number, the grain contact and the packing density index. It is thereforeimportant the determination of the above mentioned with a high degree of reliability andrepeatability. The study of the arrangement of intergranular contacts and the derivation of thevalues of pertaining indexes are carried out usually on planar images of the assemblage ofgrains either by means of visual inspection assisted by cad or by automatic image analysis.An innovative method for the automatic determination of particle coordination number, graincontact and packing density of sands based on image analysis of micrographs taken on thinsections of the sand is proposed in the paper.Tests performed on a locked sand show that the proposed method is more effective, fast andconvenient than the usual visual inspection technique, whose output depends considerablyupon the ability of the operator.