Microstructural features and strength properties of weak pyroclastic rocks from Central Italy

摘要

Large areas of Central and Southern Italy, where many historic towns are sited, are covered byrnpyroclastic materials. Their mechanical behaviour, at the border between weak rocks and granular soils, posesrnvarious problems in geotechnical modelling. The paper focuses on the results of an experimental study of thernmicrostructural features and mechanical properties of three pyroclastic deposits: a weak pyroclastic rock fromrnthe Colli AlbaniVolcanic Complex, forming large areas of the subsoil of the city of Rome; one pozzolana and onerntuff from theVulsiniVolcanic Complex, forming the slab on which the historical town of Orvieto is founded. Thernmicrostructural features are described with the aid of optical and electron scanning microscopy. The mechanicalrnbehaviour is investigated by means of a wide range of conventional uniaxial and triaxial compression. The paperrndiscusses the results of the experimental micro-structural and geotechnical investigation in order to find outrncommon features among materials having the same depositional process and possible relationships betweenrntheir microstructural features and strength.