Characterisation of a Rock Slope Showing Three Weather-Dominated Failure Modes

December 10, 2020

Climatic conditions and weather events are known landslide precursory factors and triggers. This is particularly the case for a rock slope along a section of highway in the Badlands area of central Alberta. This rock slope displays three modes of failure, which largely depend on the moisture conditions of the materials forming the slope: 1) earthflows associated with heavy rainfall; 2) rockfalls that result from differential weathering rates and undermining of various rock units, and; 3) slides of frozen slabs of highly weathered rock. Experience at the site has shown that these failure modes follow continuous weathering of the slope materials and are dominated by the moisture content of the weathered material (saturated versus unsaturated) and its state (liquid versus frozen). By understanding the weathering processes and influence of precipitation and changing air temperature on the weathered materials, we can start to identify a climatic signature that could help forecast times when the various failure modes could affect the highway below the slope, hence provide cost-effective hazard management solutions. This paper presents findings of a research project initiated to better understand the relationship between slope failure events, its failure modes, and how their timing is influenced by antecedent weather.

Roustaei, M., Macciotta, R., Hendry, M., Rodriguez, J., Gräpel, C., Skirrow, R. 2020. “Characterisation of a Rock Slope Showing Three Weather-Dominated Failure Modes.” In: PM Dight (ed.), Proceedings of the 2020 International Symposium on Slope Stability in Open Pit Mining and Civil Engineering, Australian Centre for Geomechanics, Perth. pp:427-438.