Landslide affected with an open pit excavation in flysch deposit

摘要

During the excavation of pit of Nautical High School Sport Hall in the City of Bakar, Croatia, a landslide is occurred on the slope upper of the executed excavation in autumn 1999. Through the landslide movement, the great part of landslide body was sliding in the pit and consequently the construction works were stopped. The landslide body are formed in the clayey slope deposits formed through the weathering of the flysch rocky mass. The slip surface was developed at the contact of the cover and the bedrock i.e. layers of clayey residual soils and siltstone in the bedrock. A high level of underground water and unfavorable hy-drogeological properties in the slope also affected on the sliding occur. Complex geotechnical investigation works were carried out for the purpose of drafting a landslide remediation project. Based on the results of investigation works, a landslide remediation project and the new cut construction design were made. The basic reinforced wall structure was replaced by an anchored boring pile-wall structure. The landslide remediation was based on observational methods. The paper describes the remedial works and the behavior of the landslide based on the measuring results obtained during the performance of works in phases. Results obtained from observations of geotechnical structures indicate on the behavior of geotechnical structures and allows for potential corrections. This is especially useful in complex geological conditions where site investigation works are not enough to determine the condition of all site features.