Connecting shells to piles

FLAC3D
,
1

I am trying to model the uplift that takes place at the bottom shell of an excavation stabilized with piles. The piles are installed from the begining to controll uplift having drained the soil a few meters below the excavation as shown below.
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The bottom shell is then installed under these conditions (with a stable excavation bottom), sealing the bottom of the shaft. Later, the water pressure will return to normal values, loading the shell upwards as shown below:

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I would like to connect the top of the piles to the shell structurally, as this is what is done in practice, but the piles seem to be interacting only with the zones through their coupling springs, as this allows the shell to separate from the piles.

If I attempt to connect structurally the piles and the shell using the struct link create it creates some links between nodes and zones (not what Iā€™m looking for), and still the shell is not connected to the piles.

Is there a way to create these links even if the pile nodes are not coincident with shell nodes?

Thanks in advance,

2

The shell can be connected to the top of the piles by using the {struct node join} command with the target nodes being the nodes on the top of the pile. This requires that the nodes at the top of the piles are at approximately the same locations as the nodes used by the shell elements. The only way to obtain a direct connection between a pile element and a shell element is to have a node-to-node link that emanates from the node used by the shell. In this way, the pile will still interact with the surrounding soil (i.e., zones).
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