Microstructure analysis of laboratory and in-situ compacted silts

The paper presents and discusses some results of an experimental research aimed at analysing the influence of compaction variables (w and energy) and method on the resulting microstructure of a compacted silty soil. In particular, the experimental data here discussed allow to compare the microstructure induced by different dynamic compaction techniques, comparing that characterising specimens obtained by two laboratory methods (Proctor standard and Harvard) and that of samples compacted in-situ during the construction of an embankment built for river regimentation purposes. Both undisturbed and disturbed samples have been retrieved from the embankment, the latter one with the purpose of collecting the soil subsequently used for laboratory compaction. Microstructural analyses (SEM, MIP) performed on laboratory and in-situ compacted samples evidenced a substantial similarity of the texture induced by the various compaction techniques, highlighting that laboratory compaction is suitable to provide soil samples representative of earth in-situ compacted soil.