Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.
Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
I'm having a hard time figuring out how I would do this: I need to model a static load being applied to a deep foundation (steel pile, concrete pile, etc.) in 3D, but I'm having some problems. For simplicity, I am just using two cylinders with the inside cylinder being the shaft and the surrounding cylinder representing the ground. The problem arises when I run the first step of the model, because the soil and shaft stiffnesses are not the same, so the ground settles (deforms) and it imposes stress on the shaft. What should happen, just like in real life, is that the ground would have settled, and then the hole would be excavated and the shaft installed. What I need to do is have a step where the ground settle from self-weight, and then a second step where the shaft is "installed". If I could switch materials during model steps, that would work because I could assume the shaft is made of soil in step 1, then switch it to concrete/steel during step 2, but I don't think this is possible. Another option would be to change the height of the shaft in the 2nd step by the amount of settlement so that the strain, and therefore the stress, in the shaft is zero in the second step, but I don't know if this is possible either. Does anyone know a straightforward way of accomplishing what I'm trying to do here? I can't seem to get it to work!
thanks in advance