Hi, we are using flac 2D to analyse 2 dimensions or cross section, so we must impose stable stress for loading.

If you want to impose incremental load, you can use Flac 3D for that.

You can apply an imposed displacement field using a fixed velocity at top of pile, usually very low (then your displacements) and control then with the steps number. The associated force is collected by the unbalace force at velocity applied nodes. Looking for this procedure inside the flac manuals

I think Luca's suggestion is the quickest way to do this. Apply a small displacement velocity and then record load against displacement curves in a simple FISH script. The velocity should be very slow for numerical stability, but you will see that from a bit of trial and error and seeing how noisy the data is. the FISH script can also export the data for doing some nicer graphs.

If you want to apply a series of loads, I think you will need to understand the ultimate capacity so you can select the load increments. There is a bit of time to be saved by setting up a model with a given load, then copy and paste the file into a text editor. You can then quickly edit the file make files for each load increment and run them as a batch.