Creeping Landslides – Professor Robert Haefeli, ETH Zurich

1.  Introduction

Landslides as well as creeping slopes represent a significant geotechnical hazard to the infrastructure and economy of Switzerland. About 6 per cent of the area of Switzerland is located in regions with a potential risk of landslides. Landslides and creeping slopes mostly appear in rural areas where they cause extended damage to existing infrastructure such as roads, railway tracks, etc. However, active landslides and creeping slopes have an even more severe impact on residential areas.

In 1944 Prof. Haefeli developed a theory for determining the pressure of creeping landslides on retaining walls.

Figure 1: Prof. Robert Haefeli

2.  Well-known creeping landslides in Switzerland

There are several large and well-known creeping landslides in Switzerland:

  • Castielertobel Viaduct, pier footing on a slope, canton Grisons
  • Village of Brienz, situated on a slope, Albulatal, canton Grisons
  • Village of Peiden, situated on a slope, Lugnez, canton Grisons
  • Braunwald Region, situated on a slope, canton Glarus
  • Ganter Bridge, A9 motorway, Simplon Gantertal, canton Valais
  • Slopes along the Beckenried Viaduct, A2 motorway, canton Nidwalden
  • Combe Chopin, A16 motorway, municipality of Moutier, canton Jura
  • La Frasse landslide between Aigle and Le Sépey, canton Vaud
  • Brattas landslide, ski resort of St. Moritz, canton Grisons
  • Ricaldei, slope with cantonal road Chur-Tschiertschen, canton Grisons
  • Slopes at A1 motorway, section Sitter Viaduct-Rosenberg Tunnel, canton St. Gallen
  • Railway track on a slope, Muehletobel, Saas im Praettigau, canton Grisons
  • Arschella, slope with cantonal road Disentis-Sedrun, Surselva, canton Grisons
Figure 2: Combe Chopin, A16 motorway
Figure 3: Ganter Bridge, A9 motorway

3.  How to determine creeping landslide pressure on obstacles: a problem first formulated in 1944 by Robert Haefeli from ETH Zurich

Robert Haefeli recognised that the kinematics of the problem implied that conventional active and passive earth pressure theories could not be applied. He developed complex formulas using a limit equilibrium approach and derived an approximate solution with several assumptions and simplifications based on experience. Since then, the simplified Haefeli solution has been widely applied for designing and analysing landslide retaining structures.

Haefeli published his theory and formulas in the Schweizerische Bauzeitung in 1944 (Swiss Construction Journal, 124, November 1944).
[https://www.e-periodica.ch/cntmng?pid=sbz-002:1944:123::654, https://www.e-periodica.ch/cntmng?pid=sbz-002%3A1944%3A123%3A%3A669]


Creeping landslide earth pressure can be determined as follows (simplified Haefeli formula):

When seeking the maximal value of the earth pressure force, the maximum value of function  is to be determined. Thus follows:

Figure 4: Creeping landslide model according to R. Haefeli
Egcreeping pressure force
qangle of internal friction along surface N-M
φfriction angle 
cinclination of slip surface M-C
ψslope inclination
ωbedrock inclination
Dearth pressure force on surface N-M
Gweight of soil wedge M-B-C
Kresultant force of forces D and V
Vweight of soil wedge N-B-M
Rreactive force on surface M-C
hheight of vertical retaining wall

Many occurrences in the Swiss Alps have validated the above-described equation. It applies to a rigid wall (B-C) at the bottom of a creeping slope with a long horizontal extension. The results of the calculations deliver earth pressure values within the active and passive equilibrium state, in kN-m.

Figure 5: Brattas creeping landslide, St. Moritz: overview and Leaning Tower [9]
Figure 6: Brattas creeping landslide, St. Moritz: longitudinal section through creeping body [9]

4.  The Haefeli creeping formula in practice

The most famous examples of R. Haefeli’s creeping theory application in Switzerland are the following:

Interestingly, R. Haefeli developed many of his soil mechanics theories based on his research on snow mechanics. His PhD thesis [1] dealt with snow mechanics in relation to soil mechanics.

  • Castielertobel Viaduct, strengthening of pile footing against creeping forces Beckenried Viaduct, A2 motorway, protection of pile footing with sleeves.
    Interestingly, the concept of shafts was used in the West part of the structure, while in the East part, where the loose rock slab is thinner, the pile foundations were designed for sustaining creeping landslide pressure following Haefeli’s work.
  • Brattas landslide, St. Moritz, long-term monitoring of creeping slope and its impact on infrastructure and buildings
  • A1 motorway, St. Gallen, several bridges along a creeping slope, rehabilitation of pier foundation
Figure 7: Beckenried Viaduct, A2 motorway, protection of pile footing with sleeves [16]
Figure 6: Dietli creeping landslide, A1 motorway, St. Gallen (Gruner AG)

5. References

[1]   Haefeli, R. 1939. “Schneemechanik mit Hinweise auf die Erdbaumechanik. Dissertation ETH Zürich (in German)
[https://www.research-collection.ethz.ch/bitstream/handle/20.500.11850/134326/eth-21015-01.pdf?sequence=1&isAllowed=y]

[2]   Haefeli, R. 1944. “Zur Erd- und Kriechdruck-Theorie”, Schweizerische Bauzeitung, 124, No 20, pp 256-260 (in German)
[https://www.e-periodica.ch/cntmng?pid=sbz-002:1944:123::654]

[3]   Haefeli, R. 1944. “Der Umbau des Castielerviaduktes”, Schweizerische Bauzeitung, 124, No 21, pp 267-271 (in German)
[https://www.e-periodica.ch/cntmng?pid=sbz-002%3A1944%3A123%3A%3A669]

[4]   Haefeli, R. 1967. „Kriechen und progressiver Bruch in Schnee, Boden, Fels und Eis“, Schweizerische Bauzeitung, Jg. 85, Heft 1, 05.01.1967, pp 1-9 (in German)

[5]   Haefeli, R. 1967. „Kriechen und progressiver Bruch in Schnee, Boden, Fels und Eis“, Schweizerische Bauzeitung, Jg. 85, Heft 2, 12.01.1967, pp 21-29 (in German)

[6]   Vollenweider U., 1977. „Fundamentschaechte LVB Beckenried, Konzeption, Dimensionierung und Ausfuehrung”, Mitteilungen der Schw. Gesellschaft für Boden- und Felsmechanik, Heft 96, Fruehjahrstagung 1977, 13. Mai, Lucerne (in German)
[http://geotechnikschweiz.ch.vtxhosting.ch/wp-content/uploads/2017/04/Heft96.pdf]

[7]   Puzrin, A.M. and Sterba, I. 2006. “Inverse long-term stability analysis of a constrained landslide”, Géotechnique 56, No. 7, 483-489 [https://www.icevirtuallibrary.com/doi/full/10.1680/geot.2006.56.7.483]

[8]   Puzrin, A.M. 2008. « Forschungsarbeiten und angewandte Forschung über die Kinematik von Kriechhaengen“, Mitteilungen der Schw. Gesellschaft für Boden- und Felsmechanik, heft 157, pp. 1-10, Herbsttagung 07.11.2008, Zurich (in German) [http://geotechnikschweiz.ch.vtxhosting.ch/wp-content/uploads/2017/04/Heft157.pdf]

[9]   Puzrin, A.M. and Schmid, A. 2011. ”Progressive failure of a constrained landslide”, Proc.
R. Soc. A, published online, 30 March 2011, [https://doi.org/10.1098/rspa.2011.0063]

[10] Puzrin, A.M. and Schmid, A. 2012. “Evolution of stabilised creeping landslides”, Géotechnique 62, No. 6, 491-501 [https://doi.org/10.1680/geot.11.P.041]

[11] Oberender, P.W. and Puzrin, A.M. 2016. “Observation-guided constitutive modelling for creeping landslides”, Géotechnique 66, No. 3, 232-247 [https://doi.org/10.1680/jgeot.15.LM.003]

[12] Friedli, B., Hauswirth, D. and Puzrin, A.M. 2016. “Lateral earth pressures in constrained landslides“, Géotechnique [https://doi.org/10.1680/jgeot.16.P.158]

[13] Friedli, B., Hauswirth, D., Puzrin, A.M. 2017. “Der Kriechdruck – Erddruck auf Bauwerke im Kriechhang”, Mitteilungen der Geotechnik Schweiz, Heft 175, pp 41 – 48, Herbsttagung 26.Oktober 2017, Bern (in German)
[http://geotechnikschweiz.ch.vtxhosting.ch/wp-content/uploads/2019/10/Heft175.pdf]

[14] Oberender, P.W. Val, D.V. and Puzrin, A.M. 2020. “Mechanical Models for Hazard and Risk Analysis of Structures in Creeping Landslides”, Geotechnical Engineering Journal of the SEAGS & AGSSEA, Vol. 51, No. 3, September 2020, ISSN 0046-5828,
[https://www.academia.edu/50980924/Contents_2011_2021_SEAGS_AGSSEA_Journal]

[15] Puzrin A.M., The Leaning Tower of St. Moritz: A structure on a creeping landslide In Geotechnics and Heritage: Historic Towers, edited by R. Lancellotta, Renato, A. Flora and C. Viggiani, pp. 123-​143, Boca Raton: CRC Press, 2017. [https://doi.org/10.1201/9781315387468]

[16] Ryser, M., 2008; “Bautechnische Massnahmen in Kriech- und Rutschhänge », Mitteilung der Schweizerischen Gesellschaft für Boden- und Felsmechanik, Nr. 157, pp. 23-33, Herbsttagung 07.11.2008, Zurich (in German) [http://geotechnikschweiz.ch.vtxhosting.ch/wp-content/uploads/2017/04/Heft157.pdf]