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

Variation of the resilient modulus (M-R), elastic modulus (E), and unconfined compression strength (q(u)) 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. M-R 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 M-R-w, E-w, and q(u)-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 M-R-w relationships, which are cumbersome to determine, have been successfully predicted from the easy-to-obtain E-w or q(u)-w relationships based on such similarity. (C) 2017 American Society of Civil Engineers.