The Poisson's ratio of soil is quite difficult for us geo-engineers to obtain. I came across a problem when I tried to determine the parameters in a FEM model.
For the saturated clay in undrained condition, the poisson's ratio is seen as 0.45-0.50. But when analysising the field vibration induced by traffic transmit, the soil is simplified as a linear elastic body. So we could calculate it with K0, which is usually given in the investigation report. The calculating result is usually smaller than 0.45.
I think different poisson's ratio would have an impact on the strains in lateral directions. Was there any person knowing the effect or studying on this? Thanks a lot.
Dear Xin Liu!
I think that you are right when you say that Poisson's ratio has little effect on the vibration characteristics of the soil under stationary dynamics. Poisson's ratio affects the analysis of transverse deformations.
Alexey Beskopylny Спасибо! Dear professor, I have also asked my tutor this question. He agreed with your previous answer. But he thought the saturated soft clay which I need to deal with, had no volume change under the micro vibration. So it is better to say the Poisson's ratio is 0.5. In engineering practice, 0.45-0.49 is taken for the convenience of calculation.
Dear Xin Liu!
"...the saturated soft clay which I need to deal with, had no volume change under the micro vibration"
Much depends on what you want to get by simulating micro-vibrations. We solved the problem taking into account the change in soil volume (soil density) under dynamic influences. For loams of the 2nd category, this is of principle. Their density changes up to 10 times under load and moisture.
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