The prefailure behaviour of soils as construction material

This paper describes some aspects of the stress-strain behaviour of compacted soils used as construction material, with special emphasis given in their pre-failure mechanical response (i.e, a < 1%). The article is structured in three main parts. The first section deals with the general features of soils employed in earth structures, focusing attention on fine-grained soils. This part, basically a literature overview, describes the physical and mechanical features of such geomaterials and their current applications. The importance of investigating their behaviour in the pre-failure range is highlighted as well as the requirement of accurately control the compaction variables The second and the third parts of the paper present a series of experimental results on Metramo silty sand. The influence of molding water content on the stress-strain behaviour of the saturated material is first examined. Thereafter, its pre-failure behaviour is analysed in unsaturated state and suction controlled condition. Overall, the results suggest that molding water content and degree of saturation strongly affect the pre-failure behaviour of soils, showing that proper use of measured stress-strain properties leads to better prediction of the earth structure’s performance.