Abstract:
In this paper, an immersed tunnel case-study, corresponding to a third Tagus river crossing,
supported on liquefiable alluvial sands, is presented. Laboratory testing, namely monotonic
drained triaxial tests and cyclic undrained torsional tests, is described. Moreover, a constitutive
model, as well as the numerical work, essential to its calibration and to identify its most relevant
parameters, are presented. Model parameters, their respective reference values and tests
performed to determine directly most of the parameters, are introduced. A parameter sensitivity
analysis, conducted through numerical simulation of triaxial monotonic drained tests, is defined.
Furthermore, a parameter sensitivity analysis through numerical simulation of cyclic undrained
torsional tests, implemented both for the pre-liquefaction and liquefaction phases, is described.
Finally, some parameters are determined by fitting the model to the laboratory results.
