A serious of centrifuge model tests of side-grouting uplift piles is performed to gain an insight into the mechanism of side-grouting and its effect. Mechanical properties of the contact surface

load-displacement curves and the development of skin friction resistance are discussed and compared with the in-situ test results. A further research shows that the development of side friction on uplift piles is a progressive procedure

with a leading increase of skin friction resistance at the upper part of the pile and followed by an increase of skin friction resistance at the lower part. Side-grouting leads to an increase in the ultimate skin friction resistance and a decrease in the relative pile-soil displacement at the ultimate state. Compared with the non-grouting pile

the side-grouting pile has a higher growing skin friction in the upper and lower part than that in the middle part. Both the centrifuge model and in-situ tests illustrate that the pile with side-grouting has significantly larger uplift stiffness and capacity than that without side-grouting.