Load-holding capacity of an injection anchor
In non-cohesive soils the load-holding capacity of an injection anchor is ensured by resistance to contact shear along the root surface; usually the form of the root in these cases is close to cylindrical. In the case of anchors with a tension root the transfer of load is effected by forces of fixing the tie with cement-stone body. The tension of the anchor root leads to moving apart of contact layer grains. This signifies a local decrease of density of their packing. As the worldwide anchoring experience testifies, the efficiency of root embedment in rocky and non-cohesive soils considerably increases when the force is transferred to the root through its lower end. In such design an anti-corrosion casing envelops the tendon along its entire length, and the transfer of stresses in the embedment to the lower end of the root is ensured through a base washer or a compression tube.