Study on applicability of shale as an embankment material in railway roadbed using slake durability test

In cases of concrete slab tracks, the allowable settlement should be kept strictly below 25 mm. Settlement can cause problems such as reduced train stability, and increased cost and time of maintenance. The Gyeongsang Basin, which include Daegu, Gyeongju, and Ulsan, was constructed using rock debris of tunnel excavation as embankment material. It is mainly composed of shale rock. This shale, which weathers faster in this area, is very easily weathered and breaks along the bedding planes when exposed to wind and rain after a certain period. For this reason, cracks and fractures of the concrete tracks have occurred due to roadbed settlement. In this study, field measurement was conducted to study settlement of the shale rock fill. Also, problems in an existing slake durability test were analyzed for shale, which may be unsuitable as an embankment material. A new test method for shale was conducted and proposed. The results indicate that the samples should be exposed to air for 6 months or more to accurately test their durability.