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The RBT 503 structure of the East European High Speed Railway Line crosses the valley known as the ‘ru du Bois du Cerisier’ by means of a 24m high embankment covering a 180m long main structure in reinforced concrete. The 10m wide valley is characterised by steep slopes; the embankment intersects this valley with a 45° angle.
The geological and hydrogeological contexts are particularly delicate due to the presence of near-surface water table impregnating poorly permeable marls, topped by sensitive alteration clays in which fossil slides have been identified.
TERRASOL was called during the project preparation phase by the contractors group to determine the solicitations and deformations of the frame structure during the installation of the embankment, and to study the slopes and platform stability.
Six finite element models, corresponding to different slant profiles of the embankment, were built with the Plaxis V8 software. The embankment installation was simulated in detail: compliance with execution phasing, adaptation of the calculation model to the the real soil conditions (Soft Soil Model), consolidation of soils… Stability calculations were performed using the c-φ reduction method.
During the construction phase, the results of the measurements (including inclinometers and tests with CPTu static penetrometer) allowed to adjust the behaviour laws. Additional calculations then led to propose the implementation of additional strengthening works suited to the geometry of the project and site topography: excavation of stabilising berms at the bottom of the embankment, installation of drains, construction of piles rows.
Terrasol’s achievements:
TERRASOL produced the finite element modelisation of the embankment installation in order to:
- determine the solicitations and deformations of the hydraulic structure;
- study the embankment stability;
- design additional reinforcements (stabilising berms, drains, large diameter vertical piles).
