Physical Modelling of Pull-out Resistance in Sandy Soil by Using Large Shear Box

Soil nailing is regarded as one of the cast-in-place reinforcement methods for soil slopes to limit the deformation and increase its safety the use of which is considerably increasing due to some advantages such as short-term construction and low-cost implementation. This method is commonly used in compact and dense soils, as well as slopes where heavy machinery is difficult to access, although its use is limited in loose soils. The reason for using this method in dense soil is that the fine particles are less in this type of soil and have poor cementation, which itself causes little adhesion in the soil. In addition, a proper interaction results from the friction between the soil and the nail wall in this soil. The pull-out strength of the nails is one of the important parameters in designing nailed soil, which is difficult to estimate with high precision (Franzen, 1998). This parameter is often estimated by the design engineer when designing the nailed soil and then, verified by means of pull-out tests during construction. The researchers used field and laboratory methods to conduct pull-out tests and concluded that the pull-out strength of the soil-nail relies on various parameters such as soil shear strength, dilatation, injection pressure, nail installation method, releasing stress during drilling, as well as testing method, soil condition and the like. (Hong et al. 2017).