Gundogdu (Ri̇ze) landslides and its surrounding slope susceptibility

In this study, zone of Gundogdu (Rize) located in the Eastern Black Sea Region were examined in terms of landslide susceptibility and its stability analyzes were conducted. The study area is the region with the highest rainfall in Turkey. Heavy rainfall plays a major role in triggering landslides in this region. In this study, the relationship between precipitation and landslide was investigated. In addition, the effect of precipitation on weathering also determined the geological characteristics of the area. First of all, 1/25.000 scale geological map of Gundogdu and its surrounding was provided, the units are listed as Melyat Formation (Middle Eocene) and alluvium (Quaternary) from older to younger. 1/500 scale cross sections were generated for nineteen different landslides happened at Gundogdu in 2010, 2015, 2018, and 2021 years. Then stability analyzes were done with these data. Angle of internal friction (φ), cohesion (c), saturated unit weight, natural unit weight, dry unit weight and submerged unit weight (ϒ_d, ϒ_n, ϒ_k, ϒ'), specific gravity (Gs), porosity (n), saturation degree (SR), void ratio (e) and grain size distribution were determined with laboratory tests of soil samples which were taken to determine the engineering properties of soils located in places which stability calculations would be held. Following the results of these experiments, stability analyzes were done with 4 different methods (The Zero angle of Shearing Resistance Method, Ordinary Method of Slice, Bishop Method of Slices, and Janbu Method) according to the possible sliding surfaces that were plotted from geological section of landslide. As a result of these data, this region poses a great danger specially after rainfall with the effect of weathering. For this purpose, needs to be done for the prevention of landslides have been introduced.