The assesment of rockfall analysis near a railroad: a case study at the Kızılinler village of Eskişehir, Turkey

Abstract

Rockfalls from basaltic lava flow hills and the rockfall hazard for the railroad passing along the Kizilinler village (Odunpazari/Eskisehir) were investigated in this study. Rockfalls are detected between 14 + 000 and 18 + 750 km on the Eskisehir-Kutahya railroad. This part of the railroad is controlled daily in case of rockfall, and the falling blocks on the railroad are cleared by workers. The rapid weathering of the tuff litology under the basaltic lava flows is the cause of the rockfalls. As a result of the weathering tuff unit, the basalt rock particles fall along the discontinuity surfaces due to the gravity forces. The geology of the rockfall region, the properties of the falling rock blocks, and the length to the railroad were investigated during the field study. During field studies, the rock blocks, greater than 5 m diameter that had passed to the other side of railroad, were recorded. In order to define the geologic properties of the rock mass and joint properties, two scan-line surveys were performed in the study area. A series of the rock block falling simulation studies were held with a computer program. The hazard for the train railroad was determined. A series of simple regression analysis was carried out between the fall height, the horizontal length of the rockfall, and the volume of falling rock blocks, and new empirical equations were determined. The evaluation of the estimation performances of some existing empirical equations for the determination of the runout distance of the rockfall using this study data was also performed. However, the prediction performance of the equations proposed in this study and the previous studies was not significant, except empirical equations derived between the fall height and the horizontal length of rockfall. The Rockfall Risk Rating system was applied at the selected slope sections along the study area. Consequently, the study area was classified as under medium risk. Active and passive protective measures were suggested for the study area.