Modulus-Suction-Moisture Relationship for Compacted Soils in Postcompaction State

• Published in: Journal of geotechnical and geoenvironmental engineering Vol. 135; no. 10; pp. 1390 - 1403
• Main Authors: Sawangsuriya, A, Edil, T. B, Bosscher, P. J
• Format: Journal Article
• Language: English
• Published: Reston, VA American Society of Civil Engineers 01.10.2009
• Subjects: Applied sciences; Buildings. Public works; Exact sciences and technology; Geotechnics; Soil investigations. Testing; TECHNICAL PAPERS; Suction; Shear modulus; Unsaturated soils; Compacted soils; Moisture; Compaction; Experimental study; Experimental result; Shear waves; Soil water properties; Soil test; Soil compaction; Water content; Soil water; S wave; Stiffness; Unsaturated soil; Application
• ISSN: 1090-0241; 1943-5606
• DOI: 10.1061/(ASCE)GT.1943-5606.0000108

Despite clear evidence, changes in mechanical properties (i.e., stiffness or modulus) of compacted subgrades in response to subgrade moisture regime changes after construction have rarely been investigated in the geotechnical profession. In particular, when in-service assessment of pavement subgrade is made, the modulus-moisture variation should be addressed on the basis of unsaturated soil mechanics. This study presents the unsaturated small-strain modulus behavior of five predominately fine-grained compacted subgrade soils. The small-strain shear modulus ( Go ) of saturated compacted specimens subjected to a desorption soil-water characteristic curve (SWCC) was evaluated using bender elements. A test apparatus was designed to apply two stress state variables, the net confining pressure and matric suction, during the Go measurements. The relationship between Go and the SWCC under a constant mean net stress was developed. Additionally, the effect of compaction moisture content, compaction energy, and soil type on the Go -SWCC relationship was investigated. Finally, a relationship describing the small-strain modulus behavior of unsaturated compacted soils is proposed.