Seismic Behaviour of Excavations Reinforced with Soil-Nailing Method

Soil nailing is an in-situ soil reinforcement technique that is used to enhance the stability of land slopes, retaining walls and excavations. This technique involves the installation of closely spaced and slender reinforcing solid bars, into the pre-drilled holes, which may be different in terms of length and angle of drilling. In this paper, the effects of length and angle of installed bars on the seismic behavior of excavations are investigated. For this purpose, a parametric finite element study was performed and dynamic time-history analyses were carried out using Tabas (Iran, 1978) and Manjil (Iran, 1990) earthquake ground motion records. The results of the investigation demonstrate that the length, angle, and distance of the nailing bars influence the acceleration response as well as the vertical and horizontal displacements at the excavation surface during excitations. Furthermore, it is shown that the overburden weight, soil type, and earthquake acceleration influence the seismic stability of soil-nailed walls and the amplification factor. In the final part, a case study of soil-nailed wall constructed for pit stability in "Tehran's Tohid Saraye-Mahalle" is investigated.