Preventing Block Penetration in Tunnel Stability Analysis using 3DEC

3DEC
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1

Hi everyone,

I am simulating a plane strain model in 3DEC for tunnel stability analysis. In the following example, after roof failure, the unstable blocks move towards the tunnel floor and penetrate the floor elements.

I want to know how I can prevent this penetration and allow the blocks to sit on the floor without any penetration.

Please let me know if I need to define any specific parameters.
tunnel_failure

Thanks!

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2

In theory, contacts should form and the penetration should not occur. Are you running in large strain? With all the default parameters for contact update etc.? What version are you running?
You can send the data file(s) to 3decsupport@itascacg.com and we can look at it.

3

Hi Jim,

Thanks for your reply. I am using version 9.0. The block penetration occurs both in small and large strain modes. I have sent my codes for more review to 3decsupport.
here’s the results in large strain:

tunnel_failure_large strain
tunnel_failure_large strain705×681 24.2 KB

Thanks

4

Thanks for sending. 3DEC is working correctly. In the plot above, the displacement is magnified 1.5x so maybe it looks like there is penetration. If I run it longer (in large strain), and plot it without magnification, it looks like the plot below. Note that a couple of small blocks are free falling since they are outside of the constraining host rock in the y direction.

longer
longer3800×2433 280 KB

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5

Thanks that solved the issue.