Summary
This session focuses on numerical analysis of shallow tunnels in uneven terrains, which frequently cause soil-structure interaction and slope stability problems. Such complex soil-structure interaction problems can only be solved by numerical analysis, which provides complete information on the stress-strain conditions of the tunnel,
the surrounding soil mass and slope. The stress state induced by construction of a shallow tunnel (secondary stress state) is three-dimensional (3D) in general. The correct simulation of the 3D load transfer, occurring ahead of and behind the tunnel face and resulting in transverse and longitudinal arching around the unsupported section at the tunnel face, is of particular importance.
In the training session, the procedure to analyze a tunnel with an umbrella reinforcement system in FEM. 3D modeling is carried out, beginning with the import of a CAD file and ending with the review of the results by different methods. Additionally, some unique tools such as the Tunnel Wizard are shown, as well as examples of various excavation methods such as NATM and Tunnel Boring Machine. Finally, the functions of the post processor are shown to extract key results, such as the displacements around the tunnel in different stages of excavation or the axial forces in the support, to facilitate the optimal design of the reinforcement.
Presentation Slides
Key Points
• 3D CAD geometry amount
• Modeling of umbrella tunnel
• Amount of topography and strata
• Meshing of 1D, 2D and 3D elements
• Definition of excavation stages
• Verification of deformations, structural efforts and reinforcement
• Extraction of displacement graph over time
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Speaker : Angel Francisco Martinez Category : Geotechnical Software : midas GTS NX Date : 2017-12-13 |