Experimental Validation of Suction Stress Characteristic Curve from Nonfailure Triaxial K0 Consolidation Tests

• Published in: Journal of geotechnical and geoenvironmental engineering Vol. 139; no. 9; pp. 1490 - 1503
• Main Authors: Oh, Seboong, Lu, Ning, Kim, Tae-Kyung, Lee, Young Huy
• Format: Journal Article
• Language: English
• Published: Reston, VA American Society of Civil Engineers 01.09.2013
• Subjects: Applied sciences; Buildings. Public works; Exact sciences and technology; Geotechnics; Measurements. Technique of testing; Soil investigations. Testing; Technical Papers; Suction; Shear strength; Triaxial test; Experimental study; Retention; Modeling; Triaxial tests; Experimental result; Effective stress; Consolidation; Soil test; Testing equipment; Suction stress; Soil consolidation; Saturated soil; Saturated soils
• ISSN: 1090-0241; 1943-5606
• DOI: 10.1061/(ASCE)GT.1943-5606.0000880

AbstractIn recent years, the suction stress characteristic curve (SSCC) has been shown to represent a key constitutive relationship for defining effective stress in variably saturated soils. The SSCC can be deduced either from shear strength tests under variably saturated conditions or from soil water retention tests. This paper provides an alternative way to obtain the SSCC by conducting nonfailure K0 consolidation tests. Multiple remolded specimens from two different granitic residual soils, a silty sand (SM) and a clayey sand (SC), were evaluated in suction-controlled triaxial tests under K0 conditions. The results from these tests show that the stress paths for remolded specimens with different initial suction values differ during K0 consolidation when plotted in terms of the net normal stress, but follow a single path when plotted in terms of the effective stress defined using the SSCC. This observation confirms the validity of the effective stress principle before failure. Further, the results of the shear strength tests under different matric suctions show that the failure envelope can be uniquely defined by the effective stress representation, a reconfirmation of the validity of the effective stress principle in describing the shear strength behavior of soils. The results obtained from the K0 consolidation tests also reveal that K0 (or the horizontal to vertical stress ratio) defined by effective stress is invariant to matric suction, whereas K0 defined by the total stress varies greatly with matric suction. These results provide a further confirmation of the validity of the effective stress principle. Because the SSCCs deduced independently in this study from shear strength tests, soil water retention tests, and K0 consolidation tests compare favorably with each other, the SSCC-based effective stress can be used to describe the consolidation and shear strength behavior of unsaturated soils.