RICARTE, A. V. D.; RICARTE, Alysson Victor Daniel.
Abstract:
Shallow foundations are widely used as a foundation solution for small and medium sized works
in engineering, however, their use depends directly on the quality of the soil on which it will be
laid. Once the soil does not present adequate resistance, more expensive solutions, such as deep
foundations, are required. In order to reduce costs in the face of this problem, the improvement
of soil characteristics with cement, discussed in this paper, presents itself as a possible viable
and affordable solution, however, it is necessary to know the gain in compressive strength
achieved with the soil improvement with cement. For this study, the natural cohesive frictional
soil from the experimental field was treated with a mixture of Osório sand with a 7% content
of Portland cement CP V-ARI, used in the proof loading tests taken from the literature, which
were tested with a 30 cm diameter plate for three different layers, with a constant thickness of
30 cm, and variable width of 45, 60 and 90 cm, in which all showed significant gains in load
capacity of the soil, thus proving to be a viable alternative for use in the foundations of footings,
so it is necessary methods that reliably assess the load capacity of this new soil, so that its
application is safe and effective. Therefore, the present study evaluated the best method to
calculate the bearing capacity of a soil improved with cement. The methods Myerhof, Thomé,
Meyerhof and Hanna and Brinch-Hansen were evaluated. Thus, it was possible to realize that
the Meyerhof method overestimated the values of bearing capacity, with a tendency for the
values to move away from the higher the treated layer when compared to the proof load tests,
as in the 90 cm layer, reaching 520.75% of the test value, thus presenting itself as inadequate
for this purpose. The Thomé method proved ineffective because it did not consider the effect
of the change in the treated width, presenting fixed values for the three layers. The Meyerhof
and Hanna method overestimated by about 300% the values for the three layers studied, also
proving ineffective in the analysis for soil improved with cement. The Brinch-Hansen method,
on the other hand, showed the best results, reaching a difference of 16.04% for the 45 cm layer.
However, it showed a tendency to deviate from the test values the larger the treated layer,
reaching a difference of 102.78% for the 90 cm layer. Thus the results achieved by the methods
mentioned above showed to be ineffective to evaluate the load capacity of soils improved with
cement, reinforcing the need for further studies in this area in order to establish a safe and
effective method, since the advantages that this solution can bring in economic terms.