A method for predicting mechanical behaviour of HPJG–Anchors – Part I: Mechanical characteristics and load transfer models

This paper deals with a new type of Anchor with an underreamed-segment formed by High Pressure Jet Grouting (HPJG–Anchor) of which the load–displacement behaviour is seldom studied. A numerical pull-out experiment is firstly conducted using FLAC3D to reveal the basic mechanical characteristics. Based on the simulation results, the failure modes and loading stages of HPJG–Anchors are summarized. For one important failure mode, the methods for analyzing all the ultimate resistance components are theoretically presented. Then, the load transfer models for the end resistance and frictional resistance are analytically established, respectively, using the cavity expansion theory and shear displacement method. These load transfer models can effectively consider the nonlinear load transfer characteristics and the coupled–decoupled behaviour of the grout–soil interface. They can then be used to predict the load–displacement behaviour of HPJG–Anchors using analytical solutions or nonlinear rod system finite element methods.