This publication was produced as part of the WEAMEC research project “REDENV-EOL”, led by Gustave Eiffel University (ex: IFSTTAR) and funded by the Pays de la Loire Region.
The use of helical anchors has expanded in recent years although the understanding of its behavior is still unsatisfactory. The uplift capacity of multihelix anchors in sand has been estimated using breakout factors, which vary with the sand friction angle and embedment ratio. These factors are affected by the disturbance produced by screwing the helices into the sand mass, which is more significant in the soil above the upper helices than above the bottom helix. However, the number and position of the helices (upper, intermediate or bottom) is not taken into account in the prediction of the uplift bearing capacity of the individual helices of helical anchors. The current investigation reports the effect of the number of helices on the breakout factor of helical anchors, measured from centrifuge tests in sand. Twenty-six tensile load tests were performed on different model anchors installed in sand samples with two different relative densities. The findings show that for helical anchors in dense sand, the values of breakout factor of the upper helices are lower compared to the bottom helix; however, for the looser sand case the values are similar.