Water pressure in the gap between pile and soil

Question

Hello, I have a doubt whether the Plaxis-3D could simulate the water pressure in the gap between pile and soil. The background of this is when cyclic load applied at the offshore monopile, the gap would appear at least on one side of pile, which would reduce the lateral capacity of soil. I know in the Plaxis-3D, gap closure is setup to adjust the interface condition, where compression takes effect until there is contact between the pile and the soil, when the load is reversed. But in the process of this, dose water pressure in the gap will take effect, as I marked in the above picture? If so, how could be proved?

Berk Demir · Accepted Answer

This is a very good question. Let's see what happens when a pile is loaded laterally. By going back and forward, it creates a gap between soil and pile. Also, there is a wedge failure possibility. So, any soil at the top near the pile is really disturbed. 
 What can we see in Plaxis? Plastic points near the pile can be seen easily which simulates the wedge shaped failure. 
 Filling of the gap with water is documented in the papers, but it does not add any additional load to the pile, does it? We already have water defined in the model that exerts pressure, after you have a gap between soil and pile, you can see the ground water, that's all. So there is nothing to model there. 
 The more important part, which is also treated with compression only p-y curves in the analytical approach, is -as you said- gap closure. That will affect the results significantly.

Water pressure in the gap between pile and soil

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