Peanut launch chamber
Peanut launch chamber
The Silvertown Tunnel is a 1.4 km long road tunnel under the River Thames in East London that will connect the Greenwich Peninsula and West Silvertown. The tunnel is built with TBM, and the launch chamber is designed as a multicellular peanut formed by four connected circular shafts of diameter 21 m made of secant piled walls. This paper shows pros and cons of different models applied to the design of this innovative structure comparing also results in forces and displacements, structural 3D model plus geotechnical 2D models vs geotechnical 3D model. The 3D structural model is developed with Midas Civil3D for which the soil/structure interaction is characterized by analytical modulus of subgrade reactions. The earth pressure is obtained using the axisymmetric Plaxis2D model. The 3D geotechnical model is developed with Plaxis3D that allows the soil/structure interaction to evolve through the construction stage process. Finally, deflections are compared with on-site data in a back analysis process concluding that when structure elements can be considered as linear elastic the 3D geotechnical model is a more accurate design method because it considers the geometry of the system as well as the stress state for each phase of the construction sequence.
Belen Martinez-Bacas; Marta Perez
10th European Conference on Numerical Methods in Geotechnical Engineering (NUMGE2023)
8. Excavations and retaining structures
https://doi.org/10.53243/NUMGE2023-318
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