PENETRATION RESISTANCE VALUE ALONG COMPACTION CURVES

Complete compaction curves of miscellaneous natural soils and sand-clay mixtures were determined. The simple compression resistances or the penetration resistances were simultaneously determined. On compaction curves a particular water content appeared, the compaction sensitivity threshold (CST), linked to the clay content, the compactive force value, and the clay mineralogy. It is shown that this CST appeared also as a particular water-content value an resistance curves. These results showed that the maximum dry density had no effect on variations in these resistances. As the water content increased from the CST, the penetration resistance or the simple resistance decreased to zero, a value at which soils might he considered saturated. It is shown that when the water content was lower than the CST aggregates remained individualized and then the hypothesis that the day content still did not have its lubricating action was reinforced. This lubricating action appeared as the water content was higher than the CST.