Research On Structural Durability Of Exceptionally Large Scale Underground Railway Station

Based on the large-scale underground railway station of Badaling, the article summers up the analysis methods of underground stations durability.The article quantitatively analyzes negative influence of degeneracy of Badaling Station from two different angles of materials and structures. And then it predicts the durability life of the underground stations. Based on the results of the analysis, the article finally summarizes the pre-existing experience to improve the durability of the structure system of bandaging underground station.Badaling underground railway station which is located in the5A level scenic areas, national nature reserves is the key project for new Beijing-Zhangjiakou Railway and it also has great significance of economic and culture. Therefore, it is given strict durability requirement. By analyzing the status and progress of structural durability research, the article concludes the main degradation factors which influence durability of the station and its mechanism, and analyzes station’s durability by referencing method for common structure. Considering the complexity of Badaling underground station, we should analyze not only the durability of the material degradation but also consider the impacts of degradation on the safety factor of structural system from the point of view of support-surrounding rock interaction. With the engineering examples, this paper includes the following parts:(1) The article provides a solid overview of Badaling underground station and summers up research result and trend in the field of durability by consulting reference extensively. And then the article puts forward ideas and main method.(2) From viewpoints of material science, the article concludes the main degradation factors which influence durability of the station and its mechanism and chooses congruent mathematical model by comparison existing research for durability calculating which is used for calculating the service life of Badaling underground station in the fifth chapter.(3) From viewpoints of structural mechanics and considering the mechanical impact on support-surrounding rock system of lining degradation, I perform the following work: by using finite difference software FLAC3D, I perform numerical simulations in pre-designed construction of Badaling underground station to grasp the surrounding rock situation of excavation without support. And then I check the key points to quantitatively analyze the impact of degradation of support system on surrounding rock.(4) The article gives a detailed introduction on durability lifetime classification and chooses the smaller of lifetime of crack width and reinforcing bar corrosion criterion and of bearing capacity criterion for criterion of Badaling underground railway station by consideration the significance of it. And the article also concludes that the sensitivity of station’s service life on liner crack is higher than on the fall of safety factor.(5) In the end, the article summarizes the above study, references the existing engineering experience gives some comprehensive method and technology to improve the durability of the underground railway station.