Tests on shearing creep of anchor-soil interface and its empirical model

A novel creep test method for anchor-soil interface is proposed to investigate the shearing creep characteristic of anchor-soil interface for grouted anchors in soil. The corresponding test apparatus is also designed and manufactured. The shearing creep curves of anchor-soil interface in multi-stage loading are obtained, and they can be transformed to the creep curve at each specific loading level by employing Chen's method. The results suggest that the power function and modified-hyperbolic function demonstrate good performance in the fitting of displacement-stress and displacement-time relationships respectively. A novel empirical creep model for anchor-soil interface is established based on these fitting techniques, capable of fitting and predicting the decayed creep curve at each stress level in a better agreement. On the basis of this decayed creep model, the accelerating (damage) creep model applicable to accelerating creep phase is proposed by introducing the Kachanov damage factor to represent the accelerating creep damage for anchor-soil interface.