Peteris Skels and Kaspars Bondars from the Riga Technical University (RTU) set out to examine slope stability and landslide triggering mechanisms in colluvial soil in deep river valley slopes. Most of the landslides in Latvia evolve in deep river valleys after heavy consecutive rainfall in Autumn or rapid snowmelt in Spring (Latvian Geological Survey, 2003).
The change in groundwater flow and levels effect, the stress state in the soil and creates seepage pressure. Soil is divided into saturated and unsaturated zones. Unsaturated soil parts after water infiltration or exfiltration, intense rainfall or melting snow can lead to the soil becoming saturated, thus the pore pressure will increase and the effective normal stress will be reduced, therefore reducing the shear resistance. However, it is important not only to evaluate groundwater fluctuations and pore pressure changes, but also other factors such as slope topography, soil stratigraphy and geomorphology.
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