Field Tests on Axial Behavior of Grouted Steel Pipe Micropiles in Marine Soft Clay

Abstract

This paper presents full-scale field tests of grouted steel pipe micropile embedded in marine soft clay under compressive and tensile loads. The load-displacement responses, axial forces, tip resistance, and unit skin friction were measured and evaluated. The relationship between skin friction and pile–soil relative displacement in each soil layer is discussed. The bearing capacity of the micropile was improved by the post-grouting technique. After post-grouting, the ultimate skin friction of the soft clay under compression and tension was improved by 48.7% and 30.8%, respectively. The ultimate bearing capacity of the grouted steel pipe micropile under a compression load is approximately twice that under a tension load.