On the intrinsic compressibility of common clayey soils

The present research, investigates the index properties and the oedometer intrinsic compressibility of five inorganic soils containing platey clay minerals and their respective mixtures with fine silica sand. The research purpose is to: (i) establish a quantitative relationship between the liquid limit, the clay percentage and the intrinsic parameters of compressibility valid for the common inorganic soils reconstituted at an initial water content equal to the liquid limit, (ii) propose a procedure to build the intrinsic compression line for each soil investigated in order to evaluate the soil structure at the natural state. Precisely, on the basis of the liquid limit and clay percentage (not too low) of a soil, the intrinsic compressibility parameters and the coordinates of the intrinsic compression line, proposed as intrinsic state of reference, can be calculated. Hence, plotting both the oedometer compression curve of an undisturbed soil sample and the relative calculated intrinsic compression line, the natural soil structure derived from its geological history can be estimated. Since the non-platey clay minerals have characteristics very different from that of platey clay minerals, they are excluded from the present research as the organic soils are.