Appropriate modelling of the strain level dependency of soil stiffness is of great importance in order to estimate correctly the displacements of foundations under working load conditions. Soil deformations, which mainly occur in the case of well-designed foundations, are within the range of 0·001 % to 1%, therefore the assumed model should be able to reproduce stress-strain curves, especially in this interval. In the Iight of this observation, l)uasi-Iinear stress-strain relationships have been reviewed. This review inc1udes recently proposed models that overcome some intrinsic Iimitations of the conventional hyperbolic model. Model parameters were determined for a selected database of drained compression loading triaxial tests that refer to four sands with different mineralogical and physical characteristics. The sands were tested in a triaxial apparatus equipped with gauges for the local axial and radiai strain measurements, so that the stress-strain curve is accurately defined, especially in the strain interval of interest. A parameter was introduced to evaluate the capacity of each model to fit the experimental results, and especially those concerning the variation of Young's modulus with axial stra in. An attempt was also made to find a correlation between the model parameters and test conditions (void ratio, consolidation stresses, consolidation stress ratio, overconsolidation ratio). lt was seen that the last two of these factors significantly affect the model parameters. lt was also attempted to reproduce stress-strain curves obtained for different stress-paths using these correlations.
Assessment of quasi- linear models for sands.
FIORAVANTE, Vincenzo;
1998
Abstract
Appropriate modelling of the strain level dependency of soil stiffness is of great importance in order to estimate correctly the displacements of foundations under working load conditions. Soil deformations, which mainly occur in the case of well-designed foundations, are within the range of 0·001 % to 1%, therefore the assumed model should be able to reproduce stress-strain curves, especially in this interval. In the Iight of this observation, l)uasi-Iinear stress-strain relationships have been reviewed. This review inc1udes recently proposed models that overcome some intrinsic Iimitations of the conventional hyperbolic model. Model parameters were determined for a selected database of drained compression loading triaxial tests that refer to four sands with different mineralogical and physical characteristics. The sands were tested in a triaxial apparatus equipped with gauges for the local axial and radiai strain measurements, so that the stress-strain curve is accurately defined, especially in the strain interval of interest. A parameter was introduced to evaluate the capacity of each model to fit the experimental results, and especially those concerning the variation of Young's modulus with axial stra in. An attempt was also made to find a correlation between the model parameters and test conditions (void ratio, consolidation stresses, consolidation stress ratio, overconsolidation ratio). lt was seen that the last two of these factors significantly affect the model parameters. lt was also attempted to reproduce stress-strain curves obtained for different stress-paths using these correlations.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
