Abstract:
The technique of soil nailing is seldom used in stabilizing loose fill slopes because there is a lack of understanding of the interaction behaviour of nails in loose fills. A large-scale laboratory apparatus has been built to study
the soil–nail interaction in loose fill materials. Pullout tests were performed in a displacement-rate-controlled manner
on steel bars embedded in loose, completely decomposed granitic soils. The load–displacement curves have distinct
peak values followed by a sharp decrease in the pullout force. The test results also show that the normal stress acting
on the nail changes because of the volume-change tendency and arching effect of the soil being sheared around the
nail. The post-peak decrease in the pullout force is mainly due to the reduction in the normal stress caused by the
arching effect of soil around the nail. The conventional method of analysis tends to give a low interface friction angle
and high interface adhesion. The correct interface parameters can be determined by taking the changes in the normal
stress acting on the nail into account.
