Testing and Modelling of Soil Nailed Slopes

Abstract

Soil nailing is a technique to facilitate the stabilization of an existing or a newly constructed excavation/slope. With the development in field of infrastructure, transportation and other man made structures, available land has become scarce. Hence, the urge of utilizing weak and unstable ground is inevitable. Accordingly, numerous methods have been developed in the past with soil nailing being one such solution to counter this problem. newlineThe present research work is an investigation in understanding soil nailing mechanism in slopes with different types of soil nails against the conventional soil nails that have been used in the past. To achieve that three different types of soil nail have been fabricated namely smooth soil nail, screw soil nail and helical soil nail. To comprehend the response of slopes towards reinforcement due to soil nails, 36 small - scale laboratory testing of soil nailed slopes has been conducted. The soil slopes are constructed at three different slope angles of 45°, 60° and vertical cut of 90° with horizontal. Each type of 6 soil nails are used to reinforce the soil slope at four different nail inclinations of 0°, 15°, 20° and 30° with horizontal. Thus, effect of slope angle and nail inclination on soil nailing mechanism is studied. The optimum inclination of soil nail to corresponding slope is angle determined. The variation in soil nailing mechanism with change in nail type from conventional smooth nail to screw nail and similarly to helical nail is also examined. This enable to assess the behavior of soil slopes to change in nail geometry and nail installation method. A gradual increasing surcharge load is also applied at slope crest to study load deformation of soil - nailed slopes in comparison to unreinforced soil slopes for all slope angles. newlineThe failure mechanism, failure surface and nail forces generated along nail length during slope failure are also determined from model testing.