Instrumentação de um modelo físico de estrutura de solo reforçado com geogrelha.

Abstract

The use of reinforcement elements in reinforced soil walls results in structures with a mechanical performance superior to others not using these elements, allowing, besides, that structures reach tall heights and steeply inclined slopes, which would not be possible without soil–reinforcement interaction. The most traditional sizing methods for reinforced soil structures are based on the Limit Equilibrium theory and in the adoption of simplifying hypotheses for the sizing of a generic structure, whereas these do not consider particular conditions to which each structure is subject. Therefore, through these methods, the anticipation of future efforts is usually conservative and produces oversized and more costly projects. The instrumentation of reinforced soil structures has been used for the development of sizing methods to evaluate not only parameters such as the magnitude of tractive efforts acting on the reinforcement, but also the vertical and horizontal displacements of the reinforced soil walls. By monitoring real work on retaining walls or physical models built in the laboratory, it is possible to evaluate the influence caused on the development of traction loads by several components of reinforced soil structures, such as the type and spacing of the reinforcement, and the type and inclination of elements in a given side of the wall and in the soil fill. In this work, an instrumented physical model was developed with a geogrid-reinforced soil structure whose front side was made of concrete blocks, which was subjected to overloads of up to 55 kN/m2 . Its deformations, and, consequently, the tractive efforts produced on the reinforcement layers, were monitored with the use of strain gages. The results obtained through the instrumentation were compared with tractive effort estimates by means of traditional AASHTO and Simplified Stiffness methods. In general, the estimation of efforts through continuous monitoring proved to be less conservative than the estimation obtained by the AASHTO method and more conservative than the Simplified Stiffness method. The percentage difference between the estimation of effective efforts across the three methods tends to decrease as the overload acting on the instrumented physical model increases.