https://communities.bentley.com/products/geotech-analysis/f/forum/231810/tunnelling---settlement-volume-lossWith a Plaxis 3D analysis of a simple tunnel in granular material, I&#39;ve activated the tunnel structure before deactivating the soil volume within the tunnel in the next stage. Will this predict the ground settlement and predicted volume loss? Or willen-USTelligent Community 12https://communities.bentley.com/thread/718725?ContentTypeID=1Mon, 27 Jun 2022 16:11:35 GMT6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:4f8fd683-67f2-4773-8cc0-b8d6bf3e3d0bStefanos Papavasileiou<p>Dear James,&nbsp;</p> <p>You firstly mention that you have only activated the structural elements without deactivating the soil. That means that you would not really see any change in deformation, but only due to the unit weight introducing an out-of-balance in the analysis: <br /><a href="/products/geotech-analysis/w/plaxis-soilvision-wiki/45962/reduction-of-stiffness-does-not-lead-to-a-change-in-displacements">https://communities.bentley.com/products/geotech-analysis/w/plaxis-soilvision-wiki/45962/reduction-of-stiffness-does-not-lead-to-a-change-in-displacements</a></p> <p>I am not sure how you expect activating a structure to consider volume loss. Indeed, that would require using a surface contraction or simply by allowing the tunnel to converge (stiff rock, hopefully without failing).</p> <p>In principle, with PLAXIS 3D, you can simulate the exact steps you would have in reality, e.g. check the tutorial of our TBM:&nbsp;<a href="https://communities.bentley.com/products/geotech-analysis/w/plaxis-soilvision-wiki/45577/plaxis-3d-tutorial-06-phased-excavation-of-a-shield-tunnel">communities.bentley.com/.../plaxis-3d-tutorial-06-phased-excavation-of-a-shield-tunnel</a></p><div style="clear:both;"></div>