Investigations on load-bearing behavior of soil nailing combined with flexible facing for slope stabilization

Abstract

Soil nailing combined with a flexible facing made from steel wire meshes is a commonly used and economically efficient structural system for slope stabilization. Soil nails reinforce the natural soil, which strongly decreases earthwork compared to other retaining and supporting systems. The steel wire mesh ensures the transmission of force and guarantees the safety against local and global slope failure. In a first step the paper describes the structural system of soil nailing combined with flexible facing. For instabilities near the surface (local instabilities) state of the art calculations are outlined. To verify and improve the existing designing approaches, full scale in situ tests were conducted. Among others, different flexible facing systems, nail arrangements, and soil conditions were investigated. The flexible slope stabilization system and the soil were installed in a large box with a dimension of 12 m x 10 m. After the installation, the test box was lifted up stepwise using a crane. Different parameters like three dimensional deformation, rope forces, as well as the moment and normal forces in the nails were measured. The test results are used for numerical back analysis with a three dimensional finite element method. Using the validated and calibrated numerical model, extended parametric studies by 2-dimensional and 3-dimensional non-linear finite element analyses will be conducted in the future to identify the main influencing parameters.