Performance of single vertical helical anchor embedded in dry sand

Abstract

An investigation into the uplift behavior of single vertical helical anchor embedded in dry sand presented. A series of laboratory tests have been conducted to determine the effect of the embedment ratio, shaft diameter ratio and sand density against the uplift capacity of helical anchor. The laboratory tests were conducted in a small scale model in loose and dense sand. A sand placement technique was utilized over the testing program to achieve the predetermined depth. In this testing program, the uplift load and uplift displacement have measured. The observation of failure mechanism and the measurement of pullout load and the vertical displacement analyzed and discussed. A number of graphs will be plot between the uplift capacity and the factors to obtain their relationships. From the analysis, the uplift capacity is increase with the increase of embedment ratio and sand density however the shaft diameter ratio is not significantly influent to the uplift capacity. In the observation of failure mechanism, the failure surface proposed for the helical anchor embedded in loose and dense sand. For loose sand package, local failure surface observed however for dense sand package, a truncated cone shape failure surface was observed. From the analysis, an empirical model was proposed. The proposed empirical model compared with the experiment result and existing theories to verify the validity of the empirical model.