Unsaturated sand in the stability of the cuesta of the Temple of Hera (Agrigento)

摘要

In the Valle dei Templi in Agrigento seven Doric temples stand lengthwise the crest of arnrigid calcarenite cuesta over a layer of carbonate sand which lies along a thick stratum of clays. The environmentrnis highly prone to landslides since topplings of calcarenite blocks often occur. The rock slopes arernmoving back and the slope edge draw near to the foundation of the Temple of Hera Lacinia contributingrnto increase their perilous condition. To assess the role of unsaturated sands in the instability processes,rnafter the compositional and textural analysis of the material, direct shear tests and oedometer tests havernbeen carried out on sand samples initially at the natural state, with low or very low values of natural waterrncontent, and finally at higher values of the saturation degree.rnThe mechanical behaviour of sands seems one of the main causes of the instability influenced by thernpresence of an open metastable structure, which develops through bonding mechanisms generated viarnsuctions and/or through cementing material such as clay or salts.