How to calculate dynamic earth pressure around a circular tunnel?

Thank you for your post. As this addresses a question to the whole geotechnical community, I leave it open to our fellow geotechnical engineers to comment based on their experience.

Dear Manisha,

In general, you should check the results on the added interfaces around the tunnel as they provide direct results.

Note that PLAXIS even in a dynamic analysis, does not separate between static and dynamic as it simply calculates the "total" effect of the stresses due to the applied conditions. 

Check this relevant forum post, too:  RE: Seismic Ovalization Analysis of Tunnel Permanent Linings  

If i choose a point on a circular tunnel lining at interface and plot it against time then the maximum value is Max dynamic earth pressure?

I mean at that point calculation max effective normal stress

Hello Manisha,

A pre-calc curve point on an interface will return the soil stress point, as pre-calc points do not support selection on structures and interfaces are considered as such.

You can, however, save all calculation steps, select a post-calc curve point and then select an interface stress point to retrieve the results.

This will give you the full history of the interface stress point which can reveal the changes in normal stresses during the dynamic event.