29 February 2012

Video: Preventative blast to mitigate rockfall hazard

Posted by Dave Petley

Thanks to Alexandre Mathieu for highlighting this one.



On 19th December 2011 a blast was undertaken of 3000 cubic metres of rock above Ripaillère (45°13’41.69″N – 5°43’10.93″E) a few kilometres to the north of Grenoble in France.  The blast, which was undertaken to protect houses located at the toe of the slope, and the subsequent rockfall were captured on video and can be viewed on this site.  There is an image gallery of the event here.

The video is clearly a large file, so I found that allowing it completely download and then running it again was better than trying to view it as it was being streamed.

There are two really interesting things here.  First, note how a small number of boulders go a long way, even though most stop quite quickly.  These boulders, one of which can be seen to demolish a tree, tend to be moving through a combination of bouncing whilst rotating, especially where the rotation is occurring around the shortest axis.  Second, there is a nice example of a boulder being caught very efficiently by a rockfall fence.