Modelling of piles in Plaxis V8

[lysebjerg]

Hi - I would like to do an analysis on a driven concrete pile into various soil layers. I will analyse the development of stresses near the pile surface and the movement of the soil when the pile is subjected to loading. I'm analysing reasons for the increase in bearing capacity of axially loaded piles over time after the installation (driving) of the pile. When you drive several piles near each other in a pile group the bearing capacity of the last driven piles is almost allways greater than the bearing capacity of the first driven piles - and I would like to use Plaxis to analyse the reasons for this increase.

Is there any member of Eng-Tips who can help me to make a model in plaxis so that I can do the analysis that I've written about?

Unfortunately I do not have a version of Plaxis that can do dynamic analysis.

Thank you for any help!

 

[ashjun]

Hi,
Two of the popular geotechnical FE programs (Plaxis and perhaps SageCrisp) are unable to simulate pile installation wherein the soil has infinite strain (from zero diameters to the diameter of the pile). I could suggest that you may use an expansion of the cylindrical cavity from a certain initial radius say a1 (initially in equilibrium) to a higher radius say a2 so that the volume of the cavity remains the same (you may find reference under Mark Randolph of UWA on this). There however is a catch. The pile installation is usually (and correctly) simulated by automatic mesh regeneration technique (unavailable in Plaxis and Crisp). One option may be by the use of Abacus, which has such a function.
The complication of multiple piles is another issue which I am afraid is very difficult to tackle.

Please let us know of your progress.
Regards