Influência do processo de instalação de sonda nos resultados de ensaios com o pressiômetro Ménard.

Abstract

Sincc 1996, rcscarches began studies at Federal University of Paraíba (UFPB) with a pressuremeter of the type Ménard belonging to the Geotechical Research Group, located in Campina Grande. This new equipment brought a possibility innovation, in terms of field tests, as until then the pressuremeter used was the Briaud pressuremeter, which is applied potentially in studies of roads pavement. One of the major factors in a field pressuremeter is the method used for the placement of the probe in the soil. Depending on the used method and the care taken during the installation of the probe, the field test results will be of good or not good quality. The present investigation evaluates the quality of the results obtained, starting from field tests done by Ménard pressuremeter, using as techniques of insert of the probe, the preboring and the direct insert (percussion drilling). Taken as reference the field test in preboring, it was obtained that the direct insert for dynamic process increased the values of the pressuremeter modulus (Ep). This is probably due to the fact that the compaction occurs during the installation process which, by its turn, causes alteration in the area of influence of tensions in the probe, consequently causing a compressibility decrease. Regarding to the limit pressure (PL), as expected, the influence of the compaction was not significam. This was obtained by the fact that the rupture of the soil happened beyond the elastic phase. In a previous study done by William et alii (1999) it was verified that the limit pressure is more influenced by the geometric relationship of the probe than for the method used to install it.