Research On Stability Of High Slopes And Their Retaining Structures In Fengjie Relocation City In Three Gorges Reservoir Area

The Three Gorges Project is attracting worldwide attention. The migration settlement of project area is an important part of the project, and the relocation of cities and towns in the project area is most important. At the present time, the cities and towns in the project area are almost relocated, and the second stage of migration settlement is over.In the project area, because of special geological environments and lack of construction lands, many of buildings are constructed on the slid landslide bodies. And also because of large-scale cutting and filling during a short period, many new high slopes and high fills are formed. So, there are some geological problems about the buildings, high slopes and high fills to be researched. As the geological problems are covert, the geohazards induced by engineering constructions are latent, and knowledge and technologies are limited, it is necessary to investigate and study seriously such geological problems. Further more, it is the most important and indispensable to evaluate and forecast the stability and safety of the constructed projects and the constructing projects.As an example, Fengjie county is the last one of relocated cities, and the geological environment of its relocation site is most complicated. The paper researches the stability and safety of high slopes and their retaining structures related to the migration settlement engineering in Fengjie new city.Firstly, the paper introduces the general situation of migration, the geological problems related to the migration engineering and main characteristics of engineering geological works. According to the state-of-the-art of migration engineering in the Three Gorges Reservior area, the geological problems that need to be given especial attentions currently and in the future are pointed. They are geological problems induced by constructing of new cities and latent ones. Especially, it has real significance to evaluate the safety of relocated cities for the migration project.Secondly, the situations and geological environments of Fengjie city are introduced. The factors that affect the stability and safety of high slopes and their retaining structures in Fengjie new city are analyzed. The failure modes and failure mechanism of the high slopes are studied. Based on above all, the grading standards of safety for high slopes and their retaining structures in Fengjie new city are given according to related rules and criteria. The evaluated results of 152 high slopes and their retaining structures indicate that majority(85%) of them are stable and safe, and fewness(4%) of them are unstable or not safe. The rest(11%) of them are less stable or less safe.Finally, Some suggestions about stability and safety of high slopes and their retaining structures are given.