ABSTRACT: A pressurized anchor is generally created by pumping cement slurry into a hole pre-drilled in the ground, to form a long-narrow cylinder of anchor body. It was experimentally proved that pressurizing significantly improves the pullout bearing capacity of this frictional type anchor. However, mechanism of the improvement has not been clarified.
In this study, to investigate the progressive process of this mechanism, fundamental pullout model tests were performed on an aluminum rod mass that simulates two-dimensional non-cohesive grounds. Pressurization was simulated by expanding the buried frictional plates within the mass before pulling them out. During the test, displacements of aluminum rods were captured and deformation process of the ground could be visually observed by strain analysis. Series of the test were performed on loose and dense
grounds, high and low friction surface of the plates, two levels of plate expanding and varied anchors' interval.
Model test results confirmed the improvement of pressurizing to pullout bearing capacity of anchors in both loose and dense grounds, which is around 1.3-1.6 times over that of non-pressurized anchors. Besides, when the ratio (D/B) of embedment depth D to anchors' interval B lessens below 1.43, the pullout capacity of the anchors was observed decreasing.