As shown in the picture, I am simulating a suspended caisson, and I want to obtain a suspension force that will keep the caisson stationary at any depth. At present, my method is to add line displacement at the bottom of the caisson, but if I specify its x, y, and z displacement as 0, the software will not give the corresponding force, so I fixed the x, y displacement at the bottom of the caisson as 0, and the displacement in the z direction is +0.001m, so the software will calculate a resultant force. I have three questions about this:1. Is it reasonable to apply a minimal displacement in the z direction to obtain the suspension force that can make caisson suspended?2. How should I simulate the mud on the outside of the caisson to help sink (caisson is a plate element)?3. In the process of sinking, the interface elements should be activated to the final position of the caisson at one time, or to the place where they are sunk.？