Aplicabilidade do SPT e do CPT no dimensionamento de estacas apiloadas em solos colapsíveis.

Abstract

This research work has the purpose to present and to discuss the results of a campaign of penetration tests (SPT and CPT) and loading bearing test to the compression in hamered piles. This campaign was carried out on collapsible soils formed by layers of clayey sand upon a layer of clayey silt, in the municipal district of Pederneiras (SP). In this research it was compared the results of CPT and SPT with purpose of predict the fitting of the parameters K and a. There was also a comparison among some semi-empiric predicting methods based on SPT and CPT, besides theoretical methods. For the study of the influence of the collapse in this soil, were performed loading tests with previous soil wetting. The obtained results appoint that the empiric correlations were shown conservatives. It was also verified that the semiempiric methods based on CPT obtained a better convergence with the results of the loading tests, than the prediction methods based on SPT. Finally It is concluded that the effect of the soil wetting caused decrease on the value of safety's coefficient.