Performance analysis of an embankment over a soft soil deposit through instrumentation and numerical simulation

Resumo

The present paper describes the performance analysis of an embankment over a soft soil deposit. The
embankment is part of the duplication of the Brazilian Federal highway, BR 470, a major infrastructure project
that crosses several soft clay deposits in the State of Santa Catarina, Brazil. To increase stability the reference
section was reinforcement with geogrids, equilibrium berms, and stage constructions of the landfill (slow
construction) was specified combined with preloading and pre-fabricated vertical drains (PVDs) to accelerate
consolidation. The performance during field construction was mainly evaluated through instrumentation
considering the evolution of horizontal displacements and the stabilization of settlements. Given the limitations of
the methods used for control during the construction process, and a discrepancy between field settlements and
original project predictions, soil profile and geotechnical parameters were revaluated during construction, and used
in a revised performance analysis. The revised performance analysis was done in finite element software PLAXIS,
using Mohr Coulumb and Soft Soil Models. Some important considerations were observed when proceeding this
back analysis that could have been used to modify the construction process during execution. Additionally, to
analyze the effects of the inherit variability, a sensibility analysis to determine levels of possible settlements and
time of consolidation was performed.