Abstract: The rounded gravel soil deposits in Chengdu area usually have the characteristics of high groundwater. The underground structures will require a high design buoyancy. As a result, the single ground anchor will need to design for the higher ground anchor uplift capacity. However, the ground anchor is usually limited by the “critical length” and the increased uplift design load can be achieved throughout increasing the grouting diameter as well as improve the bond strength between soilgrout interface. The ground anchors, which were installed by conventional drill rigs, high pressure rotary jet grouting methods, were cyclic pullout loaded tested. The bond stress as well as the pullout failure modes of the uplift anchors were determined throughout the test results. The results indicate that the pullout resistance of high pressure jet grouted ground anchors in rounded gravel soil deposits have higher uplift resistance than the anchors with conventional grouting methods.

Key words: Rounded Gravel Deposits, Rotary Jet Grouted, Buoyancy Anchors, Uplift Capacity