The load bearing capacity and the load-elongation diagram of soil anchors

The paper presents a method for determining the load bearing capacity and the force-elongation diagram of grouted soil anchors. Analytical solution and simple graphical method based on the expanded cylindrical cavity theory serve for the determination of approximate pull-out resistance of an anchor. Anchor elongation may be calculated from the anchor force distribution which will be determined from the activation process of the pull-out resistance in consequence of relative axial displacement between the soil and the anchor body. Analysis of anchor force distribution points out that for an anchor of known geometry and rigidity the load test diagram permits the value of pull-out resistance (tu|t) and length of the pertaining activated shear strength zone (10) to be determined. L’auteur de l’article a developpe une methode destinee a determiner la portance des tirants ancres dans le sol et les diagrammes de deformation (allongement). La base de la methode analytique et graphique est la solution theorique d’une cavite cylindrique elargie dans le sol en vue de determiner la resistance a l’arrachement du tirant. L’allongement du tirant peut etre calcule en la connaisance de la repartition de la force du tirant deduite a partir du deplacement reciproque entre tirant et le sol. Les diagrammes releves au cours de la mise en tension et les caracteristiques geometriques et de raideur, donnees connues des tirants, permettent de determiner la resistance a l’arrachement specifique (tult)) at la longueur (lo) de resistance au cisaillement appartenant a la force donnee.