YIELD DESIGN SOLUTIONS TO BEARING CAPACITY OF SHALLOW FOUNDATIONS RESTING ON THE SURFACE OF A GRANULAR SOIL REINFORCED BY A SOIL-CEMENT LAYER.

Resumo

Shallow foundations are recommended for suitable soils, in terms of bearing capacity and
small settlements. For sites underlain loose soils, conventional practice is either to implement
expensive deep foundations, or remove and replace the soft soils. In this context, soil improvement
with admixtures (such as cement, lime, fly ash, slag, and combinations) turns to be a viable solution.
However, designs procedures conceived to estimate bearing capacity improvement of such soils are
based on empirical methodologies. The present work aims to study the ultimate bearing capacity
problem of shallow foundations resting on the surface of a granular soil reinforced by a soil-cement
layer. Such task is accomplished by means of the kinematic approach of the yield design theory
through the implementation of several admissible virtual velocity fields, under plane strain conditions,
for purely vertical loads. A parametric study is presented as a function of dimensionless parameters,
which are defined from geometrical and strength properties. A comparison is then made, with
available results obtained in the context of reduced models tests, under plane strain conditions. The
maximum gap between the ultimate bearing capacity of the yield design theory and the reduced model
tests was of about 18%.