Processes for anchoring soil anchorages which are sunk to a greater or lesser depth, for example, when laying foundations, are well known. The currently most usual type of anchorage consists of a concrete anchorage cast at the intended anchorage site. This type of an anchorage is very demanding in terms of time since a casting mould firstly has to be dug in the soil before the concrete casting process itself can be performed. The concrete then has to be allowed to set before the anchorage is ready to be used. A further disadvantage of concrete anchorages is that they tend to disintegrate after a number of years' use. In order that the durability of the anchorage can be checked, it has to be laid bare.
In order to dispense with casting of anchorages it is also known to drive into the soil a metal object which, owing to its shape, is anchored in the soil when it has been driven in. However this type of anchorage or ground anchor is difficult to drive into the soil to a depth sufficient for the anchorage to support high loads. It is also already known to drive into the soil a metal tube, for example, which is then deformed so that reinforcement in the soil is attained.
DE-1 484 565 has already disclosed a ground anchor of the above-mentioned type. It consists substantially of a tube with a solid tip. A round bar is disposed in the tube and connected to the tip. Slots are formed in the tube above the tip. These slots are uniformly distributed along the tube and extend in the axial direction along the latter. This ground anchor is anchored in the soil as a result of the round bar and the tube disposed about the latter being driven into the soil. When the tube has been driven into the soil, an axial, upwardly directed force is applied to the round bar whilst the tube is held in place by an axially downwardly directed force. The round bar is therefore actuated such that it moves upwards out of the tube whilst the tube tip approaches the upper part of the tube. The shape of the tube is acted upon in the slotted region so that expansion of the tube is brought about in this region. The round bar can then be removed from the tube.
A disadvantage of this known type of anchorage is that it is unsuitable for deep anchorage and can only be used for ground anchors of very small dimensions. In the case of large tube dimensions and deep anchorage, the method is difficult to carry out, both practically and economically. Furthermore the method is unsatisfactory when a plurality of expanded regions are desired in each tubular anchorage in the ground.