Study of method of electrical resistance for evaluating the soil nailing integrity

Abstract

The slope improvement works with soil nailing are widely used along highways for stabilization of slope and landfill slopes. These structures differ from others, such as gravity walls or gabion meshes, because they have steel bars buried in the soil and surrounded by grouting. The major problem in soil nailing is the incomplete grouting along the hole, which can affect the performance of the structure. Moreover, soil nailing structures are buried, hence the most affordable inspection is visual, which makes more difficult to define the length and integrity of the elements. To improve the analyses and overcome the limitations, non destructive methods are used to evaluate all the elements of the retaining without disturbing the structure. The electrical resistance method can be used in the integrity evaluation of soil nailing. The methodology consists in compare the electric resistance between adjacent bars, which may conduct to different results, indicating executive failures or bar of different sizes. This paper aims to perform preliminary tests on a slope, before the construction of soil nailing, in order to understand the technique’s operation and to evaluate the influence of the electrical parameters of the soil. It was possible to notice that the evaluated slope presents lateral variation in electric resistance. Therefore, considering a future soil nailing there, it will be important to take into account the heterogeneity of the soil in results of electrical resistance.