Normalizing Variation of Stiffness and Shear Strength of Compacted Fine-Grained Soils with Moisture Content

Abstract

Variation of the resilient modulus (MR), elastic modulus (E), and unconfined compression strength (qu) with the gravimetric water content (w) and soil suction (s) for four compacted fine-grained subgrade soils from Canada was determined from experimental studies and investigated in this paper. MR was determined from cyclic triaxial tests and E and qu were derived from modified unconfined compression tests. These tests were conducted on identical specimens that were wetted or dried to achieve different values of w and s. Soil suction was either imposed using the axis-translation technique prior to performing the tests or measured using the filter paper method after conducting the tests. The measured MR–w, E–w, and qu–w relationships were found to exhibit similar characteristics when normalized using an approach proposed in this paper. The similarities in the normalized stiffness/shear strength–moisture content relationships found for the four compacted fine-grained soils were also corroborated by the experimental data for several other soils published in the literature. In this paper, the MR–w relationships, which are cumbersome to determine, have been successfully predicted from the easy-to-obtain E–w or qu–w relationships based on such similarity.