On the evaluation of the structure in sedimentary soils

Abstract

Oedometer intrinsic compressibility of common inorganic soils can be explained with a few fundamental parameters obtained from simple laboratory tests. Specifically, on the basis of the liquid limit and clay percentage of a soil (fine or semi-fine), the coordinates of its intrinsic compression line can be calculated. Hence, by plotting both the oedometer compression curve of an undisturbed soil sample and the relative (measured or calculated) intrinsic compression line, the natural soil structure derived from its geological history can be estimated. Since the natural soils generally differ in mineralogical composition, the data normalisation appears to be of fundamental importance to evaluate the soil element structure in sedimentary soil profiles. The aim of this paper is to build a unique ‘straight intrinsic compression line’ SICL correlating the compression behaviour of soils with different mineralogical compositions based on the Burland’s concept of evaluating soils structure. Specifically, it is possible to obtain the ‘sedimentation compression curve’ SCC of the intact soil elements down a sedimentary soil profile, which can be compared directly with the SICL and SCC of others soil profiles.

Keywords:

• Clays
• intrinsic properties
• laboratory tests
• one-dimensional compressibility
• soil structure