The group anchor，as one of popular foundations

is widely used. The soil deformation mechanism around group anchors when uplifting is sophisticated due to the interaction between anchors. The non-contact digital image correlation(DIC) method is used to perform model tests to study the behavior of group anchors when uplifting. The curve characteristics of uplift force-displacement relationships and soil deformation mechanism around anchors when uplifting are analyzed. The test results show that the relative density and embedment depth have significant influence on force-displacement relationships. Shallow and deep group anchors and single anchor have the similar curve characteristics of force-displacement relationship at the same relative density and embedment depth. Superposition effect is observed for group anchors. The factors such as relative density

embedment ratio and spacing between anchors have significant influence on group efficiency. The degree of influence of relative density

embedment ratio and spacing between anchors on group efficiency are obtained by deformation fields.