Study of pullout resistance of soil nails in tropical residual soil

Abstract

As a norm, most design engineers typically resort to theoretical and empirical approaches in order to determine the pullout resistance of soils while designing soil nailed retaining walls. The tendency to design based on actual field tests are minimal due to the time and cost involved while implementing such tests. Though results obtained through pull out tests done within the laboratory have been used to perform design calculations, the outcome of such test results are questionable, as such tests do not replicate precise site conditions. This research primarily juxtaposes and establishes a relationship between the theoretical and on field practical pullout resistance of soil nails in unsaturated conditions with the use of information extracted from an extensive literature review and data obtained through an actual pull out test conducted on a set of soil nails installed in predetermined locations of a 25ft high embankment spanning 70ft. This research also attempts to explore the effects of over burden pressure on the pull out resistance of the soil nails and the behavior of the actual failure surface of the soil nail, which has also been mentioned as the effective diameter in this report.