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#1 2020-08-20 10:47:08

saharf
Member
Registered: 2020-03-24
Posts: 10

[SOLVED] Rigid contact between soil (2D) and diaphragm wall (1D)

Hello everyone,
I am trying to model a sequential excavation of soil around a diaphragm wall. the model is on 2D, the wall is modeled with beam elements and the soil is modeled as D_plan with NetGen 1D-2D mesh. For initial analysis, I wanted to define a rigid contact between the wall and the soil, but I can not use any of the Liaison options because this option only defines the contact when the beam axis is perpendicular to the surface, in addition to that, it seems like it's not possible to use it for D-plan modelisation.
Does anyone have a suggestion on how to define this contact? I would really appreciate the help.
Thanks in advance.

P.S: attached is a screenshot of the mesh. the light blue line is the wall. The soil on the right side of the wall is to be excavated.

Last edited by saharf (2020-09-29 16:14:12)


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#2 2020-09-29 16:11:53

saharf
Member
Registered: 2020-03-24
Posts: 10

Re: [SOLVED] Rigid contact between soil (2D) and diaphragm wall (1D)

I managed to create a rigid contact between the soil and the beam, though I decided not to go through with a beam as a diaphragm wall, because the beam was a 3D element and the soil was modeled on plane deformation, and I was afraid it might cause some complications without me being aware of it.
anyway, here is how I did it:
I did it by modifying the mesh.
I created the mesh of the soil, with a lot of sub-meshes on the parts in contact with the wall, and then I meshed the beam (the wall) with Projection1D option, the targets were beam elements and nodes, and the sources were edges and nodes of the soil mesh in contact with the beam. this way the nodes on the beam and on the edge of the soil would be exactly the same.
Then I created a compound mesh of both of these two separate meshes, and I merged the double nodes, and then I merged the double elements.
This process did the trick, and then I set boundary conditions on the whole beam (nodes and elements) to prevent its displacement and rotation in Z direction. but as I said, because of the difference in the elements (2D and 3D) I decided not to go through with it. and eventually, I modeled the wall with D_plan elements. But I used the same trick to create a rigid contact between the wall and soil in this model as well.
I still think there should be a simpler way, since this procedure was very long and exhausting and in each step of the projection of the mesh there was a possibility of making a mistake.
If anyone out there has a better solution, I would be grateful if they could share it here.

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