Geotechnical investigation on Yeşilyurt (Trabzon) landslide and slope support design using by back analysis

In this study, Yeşilyurt village (Trabzon) was evaluated by considering to the landslide potential. The studies including determination of geotechnical properties of the soils were conducted in two stages: field observations/measurements and laboratory tests. With the seismic surveys, during the field surveys, were made electrical-resistivity method. During field studies, the electrical-resistivity, seismic refraction and ground penetrating radar methods were applied, and varied between 5-7 meters from the surface to the depth of the bedrock. Between the low resistivity values of approximately 2-6 meters, indicating the presence of water in this zone. In the laboratory studies, physical and strength parameters of the soils were determined. Grain size analysis show that the soil samples are composed of 7-25 % gravel, 25-41 % sand, 18-22 % silt and 30-35 % clay size materials. Specific gravity of the samples in the fine grained materials is determined about 2.71-2.71. Liquid limits are between 45.3 % and 56.6 %, and the plasticity index extended from 19.4 % to 27.1 %. The values of cohesion and friction angel were recorded as between 44 and 56 kPa, and 8-15 respectively. In the study, stability analysis were performed by using the results of the field and laboratory studies with two dimensional slide (X) computer program, as a result of a retrospective support-design analysis, 5 units (to bedrock) of 60meters in length,with a capacity of 420 kN anchors in order to make stable on the lower levels of the slope and 6 units (to bedrock) of 35 meters in length, with a capacity of 80 kN anchors in order to make stable on the upper levels of the slope is proposed.