A critical state interpretation for the cyclic liquefaction resistance of silty sands

Contrary to many laboratory investigations, common empirical correlations from in situ tests consider that the increase in the percentage of fines leads to an increase of the cyclic liquefaction resistance of sands. This paper draws upon the integrated Critical State Soil Mechanics framework in order to study this seemingly not univocal effect. Firstly the effect of fines on the Critical State Line (CSL) is studied through a statistical analysis of a large data set of published monotonic triaxial tests. The results show that increasing the content of non-plastic fines practically leads to a clockwise rotation of the CSL in (e ‐l np ) space. The implication of this effect on cyclic liquefaction resistance is subsequently evaluated with the aid of a properly calibrated critical state elasto-plastic constitutive model, as well as a large number of published experimental results and in situ empirical correlations. Both sets of data show clearly that a fines content, less than about 30% by weight, may prove beneficial at relatively small effective stresses ( p0 , 50 ‐ 70 kPa), such as the in situ stresses prevailing in most liquefaction case studies, and detrimental at larger confining stresses, i.e. the stresses usually considered in laboratory tests. To the extent of these findings, a correction factor is proposed for the practical evaluation of liquefaction resistance in terms of the fines content and the mean effective confining stress. q 2002 Elsevier Science Ltd. All rights reserved.

[1]  Achilleas G. Papadimitriou,et al.  Plasticity model for sand under small and large cyclic strains: a multiaxial formulation , 2002 .

[2]  Ken Been,et al.  The critical state of sands , 1991 .

[3]  Kohji Tokimatsu,et al.  EVALUATION OF LIQUEFACTION RESISTANCE OF CLEAN SANDS BASED ON HIGH-QUALITY UNDISTURBED SAMPLES , 1989 .

[4]  C. Polito,et al.  The Effects Of Non-Plastic and Plastic Fines On The Liquefaction Of Sandy Soils , 1999 .

[5]  K. Ishihara,et al.  Soil Behaviour In Earthquake Geotechnics , 1996 .

[6]  Yoginder P. Vaid,et al.  Liquefaction of Silty Soils , 1994 .

[7]  Yannis F. Dafalias,et al.  Plasticity model for sand under small and large cyclic strains , 2001 .

[8]  James R. Martin,et al.  EFFECTS OF NONPLASTIC FINES ON THE LIQUEFACTION RESISTANCE OF SANDS , 2001 .

[9]  Riley M. Chung,et al.  Influence of SPT Procedures in Soil Liquefaction Resistance Evaluations , 1985 .

[10]  Joseph Patrick Koester,et al.  The Influence of Fines Type and Content on Cyclic Strength , 1994 .

[11]  A. Schofield,et al.  On The Yielding of Soils , 1958 .

[12]  Timothy D. Stark,et al.  Liquefaction Resistance Using CPT and Field Case Histories , 1995 .

[13]  Panos Dakoulas,et al.  Ground Failures Under Seismic Conditions , 1994 .

[14]  Shamsher Prakash,et al.  Liquefaction of Silts and Silt-Clay Mixtures , 1999 .

[15]  Ken Been,et al.  A STATE PARAMETER FOR SANDS , 1985 .

[16]  S. Thevanayagam,et al.  Effect of Fines and Confining Stress on Undrained Shear Strength of Silty Sands , 1999 .

[17]  S. Thevanayagam,et al.  Intergranular state variables and stress-strain behaviour of silty sands , 2000 .

[18]  W. F. Marcuson,et al.  Liquefaction Resistance of Soils: Summary Report from the 1996 NCEER and 1998 NCEER/NSF Workshops on Evaluation of Liquefaction Resistance of Soils , 2001 .

[19]  Susumu Yasuda,et al.  Liquefaction of Artificially Filled Silty Sands , 1994 .