Effect of construction and design factors on the behaviour of nailed-soil structures

This study numerically evaluates the influence of excavation execution procedures in combination with the nail stiffness, facing stiffness and inclination, surcharge width and position and excavation near to the bottom on the behaviour of nailed-soil structures under working stress conditions. The numerical analyses are carried out using the two-dimensional finite-element program Plaxis 2D 2015. Data from a full-scale physical model of soil nailing constructed by the French national research project, Clouterre, is first used for the validation of the analyses. In the parametric study, two different excavation execution procedures are investigated. The first procedure represents the execution of small-width incremental excavation, starting from one side of the wall and progressing along the same level to the other side. In the second procedure, which can occur in the field, each level is fully excavated, and then nail installation and shotcreting are performed. The results show the effect of each execution procedure, in combination with the other factors mentioned, on the behaviour of the soil-nailing structure and indicate the first procedure to be the optimum construction process.