Rod penetration - Rod sliding over sand

I have been playing around with the rod-penetration example. I want to simulate a rod sitting on sand until the sand stabilizes under gravity. The rod would then be moved horizontally over the sand at constant speed. I then want to plot the frictional force vs. displacement. I expect that at a certain point the rod will displace without an additional increase in force. I am a novice and thus have been unable to obtain meaningful results. Some guidance would be greatly appreciated.