Uplift Performance of Anchor Plates Embedded in Cement-Stabilized Backfill

Abstract

A series ofpullout testsis presentedinthispaper andis usedtoidentifythekinematicsof failureandtheuplift responseofcircular anchor platesembeddedinsand-cementstabilizedlayersatdistinctnormalizedembedmentdepths(H/D), where H is the thickness of the treated layer andD is the diameter of the anchor plates. Experimental results show that the uplift capacity of anchor plates embedded in sand backfill layers increases considerably after mixing 3% cement with the backfill material. Distinct failure mechanisms observed for anchor plates embedded in both sand and cement-stabilized backfills are shown to be a function of H/D. The addition of cement to the sand backfill leads to an increase in uplift capacity of 9 timesfor anH/Dratio of 1.0 and of 13 times for an H/Dratio of 2.0. For sand backfill withH/D51:0, the failure surface had a truncated cone shape withaverticalinclinationof22� ,whereasforH/Dof1.5and2.0,radialcrackingwasobserved,and finalfailuresurfaceshadinclinationsof26and30� , respectively.Pulloutofanchorplatesincement-stabilizedbackfillsatH/Dratiosrangingfrom1.0to2.0exhibittwodistinctcharacteristics:(a)alinear elasticdeformationresponseatsmallpulloutdisplacementsand(b)alaterstagewhereradialfracturingofthestabilizedbackfillleadstohardeningjust prior to failure. Radial cracks starting at the top of the layer near the center of the anchor plates start to propagate only at about 90% of the final uplift failure load, irrespective of H/D. DOI: 10.1061/(ASCE)GT.1943-5606.0000785. © 2013 American Society of Civil Engineers. CE Database subject headings: Uplifting; Cement; In situ tests; Pullout; Backfills; Plates; Arches. Author keywords: Uplift capacity; Cement-treated soil; In situ testing; Pullout.