Slope stability assessment through field monitoring

Abstract: Deterministic methods have been used in geotechnical engineering for a long period, such as slope stability calculations. However, only applying deterministic methods is subjective and imperfect. There is a demand to develop a systematic methodology to link the assessed slope stability and field measurement data, which is also known as inverse analysis and forward calculation. Based on the Nya Slussen project, this thesis includes the development of a methodology, deterministic calculation for 4 cross sections using finite element program Plaxis 2D and probabilistic calculation for one section. Deterministic analyses showed satisfying results for all the studied cross sections since their factors of safety exceeded the minimum requirement. In probabilistic design, three parameters were found to have the most uncertainties through sensitivity analysis (undrained shear strength of clay, Young’s modulus of clay and friction angle of fill). Inverse analysis was done by testing different values of them in Plaxis and to try to match the displacement components provided by field measurement. After finding the best optimization for all the parameters, forward calculation gave a final factor of safety. It is suggested that both of the methods should be utilized together for better assessment.