Development of a Projection Protection Device to Prevent Third-Party Injuries Caused by Ground Anchor Ejection

　

 Photo 1 shows ground anchors that are widely used to stabilize slopes. As illustrated in Figure 1, the function of ground anchors is to apply tensile force to steel anchor rods that press the unstable soil mass?where potential slip failure is anticipated?against the slip surface to prevent soil movement. While the failure of a few anchor rods does not necessarily immediately result in visible slope deformation, there have been cases where broken anchor rods were ejected several hundred meters away. Even in case of such rare events, it is essential to ensure the safety of road users, including pedestrians and vehicles, as well as nearby residents, and to prevent any harm to third parties.

 Therefore, PWRI, in collaboration with Mie University and the Anchor Asset Management Research Association, has developed a ground anchor projection protection structure to prevent third-party injuries caused by the ejection of ground anchors. Development of the system was subject to several conditions: it had to reliably capture any ejected anchor rods as a matter of course, be of a size and weight that allows manual transportation even on steep cut slopes, and be installable on-site using rope (mountaineering rope) techniques without the need for temporary scaffolding.

 The developed projection protection system, shown in Figure 2andPhoto 2, captures the ejected anchor using a head receiver (anchor head catcher) and a friction cylinder absorbs the projection energy. The head receiver itself is also designed to be deformed and absorb energy upon impact. This significant deformation allows visual confirmation of the anchor failure, even from a distance on the road.

(Contact : Construction Technology Research Team)