Briefing: Effect of cement injection on field pullout load-displacement response of helical soil nail

This technical briefing presents an experimental investigation of the pullout behaviour of helical soil nails with and without cement injection. Large-scale field tests were conducted in sandy silty clay to evaluate the load-displacement behaviour and in situ installation torque of helical soil nails. The results indicate that cement injection increased the pullout capacity of helical soil nails by approximately 128% and reduced nail displacement by half under constant load. The capacity-to-torque ratio (⁠$kt)$ for helical soil nail differs substantially from those of vertically installed anchors/piles and was strongly influenced by the placement of the nail, soil type, and overburden pressure.