EXPERIMENTAL STUDY OF A NEW TYPE UMBRELLA-SHAPED ANTI-FLOAT ANCHOR

A new type umbrella-shaped anti-float device is designed and manufactured to perfect the traditional anchors and the model test is adopted to analyze the pull capacity.There are two groups of pull-out tests for umbrella-shaped anchor with and without grouting at anchor head.And a group of vertical pile drawing tests is done.The results indicate that the anti-float performance of the new type anchors is superior to that of over traditional vertical piles.Moreover,umbrella-shaped anchor with grouting at anchor head is better.And the reliability of the results is proved through finite element analysis.According to the mechanical analysis of the umbrella-shaped anchor,it is pointed out that the bearing capacity depends on the weight of soil pole wrapped by the anchor head and the shear strength along the interface of soil pole.Therefore the ultimate bearing capacity estimation formula of the umbrella-shaped anchor can be presented,which establishes the foundation for the engineering application of umbrella-shaped anchors.