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SUMMARY:Stiffness of Sands - Dr Sadik Oztoprak
DTSTART:20080314T163000Z
DTEND:20080314T173000Z
UID:TALK9669@talks.cam.ac.uk
CONTACT:Zelda Stuck
DESCRIPTION:Deformations of sandy soils around geotechnical structures sho
 ws that strain level is generally changing from small to medium under stat
 ic loading. In this strain range the soil exhibits non-linear stress-strai
 n behaviour which should be incorporated in the deformation analysis. To u
 nderstand and discuss the non-linear elastic sand behaviour\, a database w
 as constructed including shear modulus degradation curves of 457 tests in 
 order to produce best-fit functional relationships for shear stiffness of 
 sandy soils.\nObtaining a unique S-shaped curve of shear modulus degradati
 on\, a modified hyperbolic relationship was fitted. The new curve fitting 
 parameters\, elastic threshold strain and characteristic reference strain\
 , were defined for soil type and stress level. With these properties\, the
  proposed hyperbolic relation seems very useful to model the non-linear el
 asticity of the sands and promising to incorporate into analytical or nume
 rical methods.\nBy this means\, the proposed hyperbolic relation incorpora
 ted into FLAC3D software to model the pressuremeter tests in sand. Causing
  less disturbance in the soil and providing initial stress conditions\, pr
 essuremeter test is a powerful tool for deformation-based modelling. It is
  thought that if the observed behaviour in a pressuremeter test can be mat
 ched by a finite element program incorporated the proposed non-linear mode
 l\, then it should be possible to use the same model to predict the behavi
 our in any full-scale foundations. This presentation will give the promisi
 ng results of modelling a pressuremeter test which will lead to model some
  geotechnical foundations in the future.\n\n
LOCATION:Engineering Department - LR6
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