Numerical and experimental studies of the mechanical behaviour for compaction grouted soil nails in sandy soil

A model test was conducted for a newly developed soil nail, the result of which was compared to that of a 3D finite element method (FEM) simulation. The shape angle (β) and friction coefficients (μ) contributed to the difference in pull-out force between the model test and the simulation. Further verifications were conducted, during which the pull-out mechanisms of the soil nail for different β and μ were analysed. It was found that both β and μ have a positive influence on the pull-out force; β only affects the increase rate, while μ influences the overall pull-out force level. Three components were found to govern the pull-out force, with the component applied to the expanded cement bulk surface accounting for approximately 80% of the total. This study proves that the optimal approach for increasing pull-out force is to enlarge the diameter of the cement bulk rather than extend the nail length.