Study on dilatancy mechanism and mechanical effect of anchorage interface

Dilatancy mechanism of anchorage interface is analyzed by using microscopic model, which shows that failure of anchorage interface is of forms of climbing or gnawing and interface is with obvious dilatancy no matter what the failure form is. Analysis of macro-mechanical effect shows that influence of radial deformation of anchorage interface on chemical properties of anchorage interface is not insignificant. Influence of radial deformation on radial stress is very obvious according to theory of thick cylinder. Increase of normal stress around anchorage hole is of great significance to the improvement of shearing resistance of anchorage interface before cleavage of rock-soil around anchorage hole. Finite element model is built to study the mechanical effect of dilatancy of anchorage interface. The result shows that large radial stress is generated nearby interface due to existence of dilantancy and radial stress rapidly weakens with the increase of interface spacing and decreases to almost null in the far location from interface. Stresses of all materials of anchorage system are changed and mechanical properties of interface material are improved by radial stress. It can be easily concluded from the comprehensive analysis of dilatancy mechanism and mechanical effect of anchorage interface that anchorage interface is the weakest link of the whole anchorage system in the initial stress stage due to the existence of interface layer and failure of anchorage system starts from interface and interface layers suffer dilatancy effect after they relatively slip with the increase of load and this effect is helpful for improving anchorage force.