Effects of current suction ratio and recent suction history on small-strain behaviour of an unsaturated soil

Although the small-strain shear modulus of saturated soils is known to be significantly affected by stress history, consisting of the overconsolidation ratio (OCR) and recent stress history, the effects of suction history on the small-strain shear modulus of unsaturated soils have rarely been reported. In this study, the effects of suction history, which refers to current suction ratio (CSR) and recent suction history, on both the very-small-strain shear modulus (G0) and shear modulus reduction curve of an unsaturated soil, are investigated by carrying out constant net mean stress compression triaxial tests with bender elements and local strain measurements. In addition, the effect of suction magnitude on G0 and the shear modulus reduction curve is also investigated. At a given suction, G0, elastic threshold strain (ee), and the rate of shear modulus reduction all increase with CSR. On the other hand, the effect of recent suction history on G0 is not significant. The effect of direction of recent suction ...

[1]  S. Burns,et al.  Dynamic properties of fine-grained soils engineered with a controlled organic phase , 2013 .

[2]  J. Graham,et al.  Anisotropic elasticity of a natural clay , 1983 .

[3]  Vinayagamoorthy Sivakumar,et al.  A critical state framework for unsaturated soil. , 1993 .

[4]  C. Ng,et al.  Effects of Stress Paths on the Small-Strain Stiffness of Completely Decomposed Granite , 2005 .

[5]  A. d'Onofrio,et al.  Small strain behavior of a silty sand in controlled-suction resonant column torsional shear tests , 2002 .

[6]  Jong-Sub Lee,et al.  Bender Elements: Performance and Signal Interpretation , 2005 .

[7]  B. Simpson.  RETAINING STRUCTURES: DISPLACEMENT AND DESIGN (THIRTY-SECOND RANKINE LECTURE) , 1992 .

[8]  J. H. Atkinson,et al.  Effect of recent stress history on the stiffness of overconsolidated soil , 1990 .

[9]  B. Simpson,et al.  Retaining structures: displacement and design , 1992 .

[10]  Charles Wang Wai Ng,et al.  A new simple system for measuring volume changes in unsaturated soils , 2002 .

[11]  Buddhima Indraratna,et al.  Laboratory study of small-strain behavior of a compacted silty sand , 2013 .

[12]  F. E. Richart,et al.  Closure of "Capillary Effects on Dynamic Modulus of Sands and Silts" , 1984 .

[13]  Charles Wang Wai Ng,et al.  Effects of wetting-drying and stress ratio on anisotropic stiffness of an unsaturated soil at very small strains , 2009 .

[14]  J. H. Atkinson,et al.  Experimental determination of stress–strain–time characteristics in laboratory and in situ tests. , 1991 .

[15]  K. Stokoe,et al.  EFFECTS OF VARIOUS PARAMETERS ON THE STIFFNESS AND DAMPING OF SOILS AT SMALL TO MEDIUM STRAINS , 1995 .

[16]  C. Ng,et al.  Advanced Unsaturated Soil Mechanics and Engineering , 2007 .

[17]  Antonio Gens,et al.  A constitutive model for partially saturated soils , 1990 .

[18]  J. W. Hilf,et al.  AN INVESTIGATION OF PORE WATER PRESSURE IN COMPACTED COHESIVE SOILS , 1956 .

[19]  D. H. Gray,et al.  Voids and Granulometry: Effects on Shear Modulus of Unsaturated Sands , 1993 .

[20]  APPLICATION OF MICROMECHANICS MODEL TO STUDY ANISOTROPY OF SOILS AT SMALL STRAINS , 2002 .

[21]  M. Lings,et al.  Horizontally Mounted Bender Elements for Measuring Anisotropic Shear Moduli in Triaxial Clay Specimens , 2001 .

[22]  C. Ng,et al.  Determination of the anisotropic shear stiffness of an unsaturated decomposed soil , 2008 .

[23]  Michele Jamiolkowski,et al.  A review of instrumentation for measuring small strains during triaxial testing of soil specimens , 1995 .

[24]  R. Dobry,et al.  Effect of Soil Plasticity on Cyclic Response , 1991 .

[25]  Guy T. Houlsby,et al.  The work input to an unsaturated granular material , 1997 .

[26]  Rui Chen,et al.  Experimental study and constitutive modelling of stress-dependent coupled hydraulic hysteresis and mechanical behaviour of an unsaturated soil , 2007 .

[27]  V. Drnevich,et al.  Shear Modulus and Damping in Soils: Measurement and Parameter Effects (Terzaghi Leture) , 1972 .

[28]  Charles Wang Wai Ng,et al.  Experimental investigations of the soil-water characteristics of a volcanic soil , 2000 .

[29]  C.R.I. Clayton,et al.  Stiffness of geomaterials at very small strains , 2001 .

[30]  J. H. Atkinson,et al.  Interpretation of bender element tests , 1995 .

[31]  XuJ.,et al.  Resilient Modulus of Unsaturated Subgrade Soil: Experimental and Theoretical Investigations , 2013 .

[32]  Charles Wang Wai Ng,et al.  Inherent anisotropic stiffness of weathered geomaterial and its influence on ground deformations around deep excavations , 2004 .

[33]  C. Mancuso,et al.  Effects of net stress and suction history on the small strain stiffness of a compacted clayey silt , 2007 .

[34]  C. Ng,et al.  Modelling of shear stiffness of unsaturated fine grained soils at very small strains , 2014 .

[35]  E. Lavernia,et al.  An experimental investigation , 1992, Metallurgical and Materials Transactions A.