The mechanical behaviour of intensely fissured high plasticity clays from Daunia

The paper presents the geotechnical characterisation of a site in the Daunia region (southern Italy), Santa Croce di Magliano, which is located within the East-side border of the Apennines chain. The soils outcropping in the site form the so-called Daunia unit. They are mainly allochthonous finegrained soils, which were originally deposited elsewhere and were moved and largely deformed during the Apennines orogenesis. Therefore, they are severely disturbed and fissured. The paper first discusses briefly the geological setting of Daunia and, in particular, of Santa Croce di Magliano. Thereafter, it presents the main results of a research about the mechanical properties of two of the four main soilcomplexes assembled in the Daunia Unit: the scaly clays and the fissured bentonite part of the Red Flysch, which are excessively and intensely fissured respectively. Their mechanical characterisation results in the definition of a framework of mechanical behaviour for both the soils, representing the main features of the influence of highly intense fissuring on the mechanical behaviour of clays.