Aceleração dos assentamentos por consolidação de aterros sobre solos moles: baixa do rio Maputo em Salamanga

Abstract

The predominance of thick deposits of saturated soft clays usually conditions the rapid and safe construction of relatively heavy structures, for, in addition to the fact that the soft soils are poorly permeable, they are highly compressible and present low shear strength. Thus, the present study discusses the acceleration of the consolidation settlements of embankments on soft soils and, for that purpose, a back analysis of a monitored section of a road embankment built along the Maputo river floodplain, where prefabricated vertical drains were adopted, was carried. Then, the design of a foundation reinforced by stone columns was carried and its behaviour was simulated on Plaxis 2D v.8.6, which is based on the finite element method. The study of both techniques clearly revealed their potential to accelerate the consolidation settlements, for, in addition to the high permeability of both the prefabricated drains and the stone, both the drains and the columns are installed in a manner such that the drainage path within the clayey layer is exponentially shortened. The simulation of the reinforced foundation yet pinpointed its potential to reduce the settlements and increase the strength of the surrounding soil, thus, reducing the total volume of fill required to meet the design elevation, and, in the other hand, the global stability problem to an internal stability one.