engleski

Preliminary testing of clay activity from landslide deposits in Dubračina River Basin, Croatia

This paper presents the preliminary results of clay activity testing from landslide deposits located in the Dubračina River Basin (43.52 km2), Croatia. Numerous small shallow landslides were identified in the study area, based on the visual interpretation of high-resolution airborne LiDAR (Light Detection and Ranging) imagery. The main landslide types in the Dubračina River Basin are debris slides and debris slide-debris flows. Most of the landslide phenomena are located within complex gullies formed in the flysch bedrock. Samples of colluvial deposits from nine debris slides were tested to determine clay activity, with the main aim of establishing a potential relationship between sliding processes and activity of present clay minerals. Results of this preliminary study indicate that inactive and normally active clay minerals (i.e., kaolinite and illite) prevail in the colluvial deposits of the investigated landslides, while in only one soil sample the more active clay minerals (i.e., montmorillonite) have been found. Although the activity of clays cannot be directly related to the landslides triggering, it can be a relative indicator for identification of slope material more susceptible to sliding. The soils with lower activity generally have lower values of cohesion and can retain less quantity of infiltration water before a loss of the strength. According to these facts, soils with lower activity have consequently lower shear strength and are more sensitive to transition in weaker consistency caused by water content increasing. Those facts are very important for shallow landslide occurrences and knowing of activity of clays in a slope can be a valuable data in landslide susceptibility determination in the Dubračina River Basin.

debris slide, landslide deposits, clay activity, clay minerals, Dubračina River Basin, Vinodol Valley

nije evidentirano