Abstract ID: 3.12880 | Accepted as Talk | Poster | TBA | TBA

The morphology of the slopes, the geological and tectonic conditions and the climatic diversity contribute significantly to the high rockfall potential in the Slovenian Alps and other mountain regions around the world. In this study, the influence of freeze-thaw cycles on the occurrence of rockfall in the upper Soča Valley on limestone is analysed. The aim of the analysis was to identify periods in which fluctuations in air temperature cause pressure fluctuations in the rock that lead to volumetric expansion of fluids, which can contribute to the destabilisation of rocks and cliffs. A dataset from the Slovenian Infrastructure Agency, which contains records of rockfalls along the regional road R1-206/1029 (Trenta–Bovec) between 2015 and 2024. The temperature data comes from meteorological stations near the analysed test site. For each rockfall event, we interpolated temperature series based on nearby meteorological stations. We considered the altitude and distance to the rockfall location, with the closer stations having a greater influence. The definition of freeze-thaw cycles is based on different time periods in which the temperature fluctuates above and below the freezing point. The analysis summarises the relationship between the frequency of rockfall events and 1) the average temperatures, 2) the standard deviations of the temperatures and 3) the number of freeze-thaw cycles over periods of one week, two weeks, one month and three months prior to the rockfall events. The total length of the road is 22,124 metres, with a total of 1,045 recorded events over a period of 3,468 days. The rockfall frequency along the entire road section is therefore 0.301 events per day, or 0.014 events per day when converted to a length of 1 kilometre. The highest number of events was recorded in April (121), followed by May (116) and March (101). The lowest number of events was recorded in November (64). After August (77), a slight increase in rockfall frequency can be observed in September (82) and October (79). The results contribute to a better understanding of the relationship between temperature changes and the occurrence of rockfalls and have practical implications for risk assessment and the planning of protective measures in rockfall-prone areas.