Item: Avalanche Barriers in the Starting Zone Exposed to Rock Fall: Range of Capacity and 1:1 Rock Fall Tests With Flexible Snow Net
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Title: Avalanche Barriers in the Starting Zone Exposed to Rock Fall: Range of Capacity and 1:1 Rock Fall Tests With Flexible Snow Net
Proceedings: International Snow Science Workshop Grenoble – Chamonix Mont-Blanc - October 07-11, 2013
Authors:
- Brändle R. [ Geobrugg AG, Romanshorn, Switzerland ]
- Gröner E. [ Geobrugg AG, Romanshorn, Switzerland ]
- Margreth S. [ SLF, WSL-Institute for Snow and Avalanches Research ]
Date: 2013-10-07
Abstract: Since the introduction of flexible snow nets in the 1950’s it became obvious that such barriers provide a better performance on combined loadings of static snow pressure and dynamic rockfall impacts compared to stiff steel bridges. In various cases avalanche barriers in the starting zone have to be built under rock faces with frequent rockfall. On a qualitative basis it was found that rigid systems e.g. snow bridges made of steel are not able to withstand rock fall energies of more than 50 kJ. This is the result of a research project and case studies in Switzerland, Austria and Germany together with the alpS – Zentrum für Naturgefahrenmanagement and WSL- Institute for Snow and Avalanche Research SLF (Margreth 2006a and b). The investigations have shown that flexible snow nets have a higher energy absorption capacity which may be even more than 200 kJ. To obtain a better understanding of the interaction and performance of rock fall on snow nets and to quantify the capacity of snow nets a trial of 4 different 1:1 large scale rockfall tests with flexible snow nets have been done. With this testing it is possible to quantify the rockfall capacity of a new type of snow net. Integral part of this snow net is a rhomboidal spiral rope net with a load capacity of 220 kN/m’. The rockfall bearing capacity could be even increased by applying stronger spiral rope nets. As a result it was possible to achieve a rock fall capacity of up to 500 kJ which is ten times more compared to rigid structures. This rockfall adapted snow net system has been already installed in Austria. In this paper the project is presented and detailed information about the performed test series is provided. The results of our technical development are improved flexible avalanche supporting structures which can withstand rockfall energies up to 500 kJ leading to reduced costs for maintenance and repair respectively.
Language of Article: English
Presenters: Unknown
Keywords: rockfall, snow nets, prevention structure
Page Number(s): 836-839
Subjects: avalanche barriers avalanche starting zones
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Digital Abstract Not Available
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