Modified Rockfall Fence
Area of Application
The use of flexible-net systems for mitigating debris flows is a relatively new field of investigation. Most knowledge comes from debris or mud flow events impacting rockfall catchment fences. From these experiences, adaptations to standard rockfall catchment fences have been made over the years to improve their performance and today we see such systems used for protecting elements at risk all over the world.
Post and Rope Adaptations
The most common adaptation required for adapting rockfall fences for use in debris flow mitigation is an increase in the steel profile of the post as well as a decrease in the post spacing. Both these adaptations are a result of the high loads experiences across a field. In some situations, extra retaining ropes are required at the heads of the post or at a lower position. Extra bearing and middle ropes are another common adaptation.
Base Plate Adaptations
In some cases, changes to the base plates are deemed beneficial, whether it be the anchor pattern, stiffening of the tongue or protection measures for the anchor head.
Modifications are also used for adapting fences to handle snow load conditions due to avalanches or snow creep and are similar to those for debris flow.
Any rockfall catchment fence can serve as the starting point for a debris flow structure depending on the strength requirements. Once the load parameters are known, an appropriate system is chosen and adapted as required. Details for the various standard systems can be found under the corresponding rockfall fence system.