TY - GEN
T1 - Modeling unsaturated soil behavior under multiaxial stress states
AU - Hoyos, L. R.
AU - Laikram, A.
AU - Pérez-Ruiz, D.
AU - Puppala, A. J.
PY - 2009
Y1 - 2009
N2 - This paper presents the results from a preliminary series of conventional triaxial compression (CTC) and triaxial compression (TC) tests conducted on compacted silty sand (SM) under constant-suction states. The experiments were conducted by using a novel, servo-controlled, true triaxial (cubical) apparatus that is suitable to test 3-in (7.5-cm) per side, cubical specimens of unsaturated soil under controlled-suction states and for a wide range of stress paths that are not achievable in a conventional cylindrical apparatus. The equipment is a mixed-boundary type of device, with the specimen seated on top of a high-air-entry ceramic disk and between five flexible (latex) membranes on the remaining sides of the cube. The cell features two independent pore-air (u a) and pore-water (u w) pressure control systems via a PCP-5000-UNSAT pressure panel. Target suction levels are induced and kept constant during testing using the axis-translation technique. The technique is implemented by utilizing the s = u a testing concept (u w = 0), which plays a fundamental role in characterizing unsaturated soil behavior under multiaxial stress paths that are likely to be experienced in the field. Results from suction-controlled tests under axisymmetric conditions (σ 2 = σ 3) were used for calibration and further fine-tuning of the original elasto-plastic, critical state based framework postulated by the Barcelona Model (Alonso et al. 1990). Matric suction was found to exert a noticeable influence on the soil's stress-strain-strength behavior under multiaxial stress states. Numerical predictions of experimental stress-strain response of silty sand under axisymmetric conditions, using the Barcelona Model, were proved to be reasonably accurate.
AB - This paper presents the results from a preliminary series of conventional triaxial compression (CTC) and triaxial compression (TC) tests conducted on compacted silty sand (SM) under constant-suction states. The experiments were conducted by using a novel, servo-controlled, true triaxial (cubical) apparatus that is suitable to test 3-in (7.5-cm) per side, cubical specimens of unsaturated soil under controlled-suction states and for a wide range of stress paths that are not achievable in a conventional cylindrical apparatus. The equipment is a mixed-boundary type of device, with the specimen seated on top of a high-air-entry ceramic disk and between five flexible (latex) membranes on the remaining sides of the cube. The cell features two independent pore-air (u a) and pore-water (u w) pressure control systems via a PCP-5000-UNSAT pressure panel. Target suction levels are induced and kept constant during testing using the axis-translation technique. The technique is implemented by utilizing the s = u a testing concept (u w = 0), which plays a fundamental role in characterizing unsaturated soil behavior under multiaxial stress paths that are likely to be experienced in the field. Results from suction-controlled tests under axisymmetric conditions (σ 2 = σ 3) were used for calibration and further fine-tuning of the original elasto-plastic, critical state based framework postulated by the Barcelona Model (Alonso et al. 1990). Matric suction was found to exert a noticeable influence on the soil's stress-strain-strength behavior under multiaxial stress states. Numerical predictions of experimental stress-strain response of silty sand under axisymmetric conditions, using the Barcelona Model, were proved to be reasonably accurate.
KW - Constitutive modeling
KW - Matric suction
KW - True triaxial test
KW - Unsaturated soils
UR - https://www.scopus.com/pages/publications/84865188383
U2 - 10.3233/978-1-60750-031-5-182
DO - 10.3233/978-1-60750-031-5-182
M3 - Conference contribution
AN - SCOPUS:84865188383
SN - 9781607500315
T3 - Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering: The Academia and Practice of Geotechnical Engineering
SP - 182
EP - 185
BT - Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering
T2 - 17th International Conference on Soil Mechanics and Geotechnical Engineering, ICSMGE 2009
Y2 - 5 October 2009 through 9 October 2009
ER -