Pullout creep properties of grouted soil anchors

Abstract

The time effect behavior of soil anchors is very important in engineering design on slopes, retaining walls and tunnels. The pullout creep tests of two grouted anchors in silty clay were carried out. On basis of the creep testing data, the pullout creep curves and isochronal curves of pullout force-pullout displacement at the different time were obtained. The data of secant stiffness with time from the isochronal curves was obtained. The relational expression of pullout stiffness of grouted anchors with time was established by means of Hooke-Kelvin model. The formula of pullout stiffness of grouted anchor with time under a constant pullout force was derived. By the formula fitting the data of secant stiffness with time on two anchors, the parameters in Hooke-Kelvin model can be obtained. Based on the damage theory, the equations of the creep damage variant and the long-term pullout strength of anchor were derived. The results indicate that the long-term pullout capacity is about 85%–90% of the instantaneous limit pull strength.

Keywords

grouted anchor in soil / creep test / long-term capacity / time effect