Small-Strain Stiffness Behavior of Unsaturated Compacted Subgrade

• Published in: Proceedings of the Fourth International Conference on Unsaturated Soils 2006; Carefree, AZ; USA; 2-6 Apr. 2006 pp. 1121 - 1132
• Main Authors: Edil, T. B, Bosscher, P. J, Sawangsuriya, A, Wang, X
• Format: Book Chapter Conference Proceeding
• Language: English
• Published: American Society of Civil Engineers (ASCE) 2006
• Subjects: Civil Engineering & Construction Materials; Environment & Environmental Engineering; General References; Stiffness; Unsaturated soils; Compacted soils; Subgrades
• ISBN: 9780784408025; 0784408025
• DOI: 10.1061/40802(189)91

This paper presents an experimental investigation of the small-strain stiffness behavior of an unsaturated compacted subgrade soil. The small-strain stiffness tests were performed under two testing schemes, namely as-compacted state (at the initial compaction condition during construction) and post-compacted state (service life after construction when subject to moisture regime changes). A non-destructive elastic wave propagation technique using bender elements was utilized to monitor and to evaluate the shear wave velocity and corresponding small-strain shear modulus (Go) of the compacted soil specimens. A new test apparatus was designed to control two stress state variables, the net confining pressure and the matric suction, during the Go measurements. Finally, a model was proposed for the small-strain stiffness behavior of unsaturated compacted subgrade soil.