Down-slope variation in geotechnical parameters and pore fluid control on a large-scale Alpine landslide

A geotechnical investigation has been carried out on a large volume landslide in the Stambach Valley on the slopes above the town of Bad Goisern, Austria. Undrained loading has been considered as a means of triggering a large volume debris flow. The initiation of this landslide has been linked with the collapse of rock pillars from the rock face of Zwerchwand onto the head of the flow. The concept of pore tensions resulting from stress relief has been used to account for the time delays of up to 10 months between the loading and the reactivation of the debris flow.