CUED Publications database

Stiffness of sands through a laboratory test database

Oztoprak, S and Bolton, MD (2013) Stiffness of sands through a laboratory test database. Geotechnique, 63. pp. 54-70. ISSN 0016-8505

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Abstract

Deformations of sandy soils around geotechnical structures generally involve strains in the range small (0·01%) to medium (0·5%). In this strain range the soil exhibits non-linear stress-strain behaviour, which should be incorporated in any deformation analysis. In order to capture the possible variability in the non-linear behaviour of various sands, a database was constructed including the secant shear modulus degradation curves of 454 tests from the literature. By obtaining a unique S-shaped curve of shear modulus degradation, a modified hyperbolic relationship was fitted. The three curve-fitting parameters are: an elastic threshold strain γ e , up to which the elastic shear modulus is effectively constant at G 0 ; a reference strain γ r , defined as the shear strain at which the secant modulus has reduced to 0·5G 0 ; and a curvature parameter a, which controls the rate of modulus reduction. The two characteristic strains γ e and γ r were found to vary with sand type (i.e. uniformity coefficient), soil state (i.e. void ratio, relative density) and mean effective stress. The new empirical expression for shear modulus reduction G/G 0 is shown to make predictions that are accurate within a factor of 1·13 for one standard deviation of random error, as determined from 3860 data points. The initial elastic shear modulus, G 0 , should always be measured if possible, but a new empirical relation is shown to provide estimates within a factor of 1·6 for one standard deviation of random error, as determined from 379 tests. The new expressions for non-linear deformation are easy to apply in practice, and should be useful in the analysis of geotechnical structures under static loading.

Item Type: Article
Subjects: UNSPECIFIED
Divisions: Div D > Geotechnical and Environmental
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 18:57
Last Modified: 21 Sep 2017 01:40
DOI: