Estudo da estabilidade de um talude com variação geométrica e aplicação de contenção em solo grampeado

Abstract

This research presents a study approach on slopes stability with application of nailed soil. The use of reinforcements on slopes is required when there is possibility of ruptures, that is, when the acting tensions exceed the strength of the soil tensions, resulting in possible loss of human life or materials. The stability analysis was conducted following the Mohr-Coulomb rupture criteria and with use of the Bishop and Spencer methods with help of the GeoStudio Software 2012. For the modeling of the slope, it was necessary to determine the cohesion and the soil friction angle. Such geotechnical parameters were obtained during direct shear tests, which enabled the construction of the rupture envelopment. Humidity and granulometry tests were also performed, in order to characterize the soil which composes the mass under study. the safety factors obtained through the stability analysis of the original slope and of the others geometric variations did not meet the criteria specified by Brazilian technical norm NBR 11682 (2006) - slope stability. According to this standard norm, in order to ensure a high level of security is required for the safety factor to be 1.50, which implies the need for execution of an adequate containment system to prevent rupture. In order to determine the resistance to tearing and consequently to dimension the nail, it was necessary the use of an empirical equation which relates the peeling force with the SPT number of the soil. The methods of Bishop and Spencer applied in this research which are based on the subdivision of the unstable mass in slices, presented values very close to one to another for the safety factor. With the application of the nailed soil, one can observe a significant change in the safety factor of the original slope and all of its geometric variations studied, classifying the slope as stable according to the criteria adopted by the Brazilian Standard Norm.