Stability of artificial subaqueous slopes in sandy soils

• Applicant: Professor Dr.-Ing. Jürgen Grabe
• Subject Area: Geotechnics, Hydraulic Engineering
• Term: from 2014 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 255415996

During the construction of artificial submarine pits under offshore conditions it should be considered that the long-term slope-inclination is less than onshore due to hydrodynamic actions (e. g. flow, waves, earthquakes). Our research project is focused on changes of geometry of submarine slopes in non-cohesive soils (erosion, sedimentation, breach failure, liquefaction failure) due to surface waves which cause excess pore water pressures leading to a reduction of effective stresses and in case of submarine slopes to changes of slope geometry depending on wave length L, wave height H, water depth h and permeability k of soil. During our preliminary work we investigated such processes based on the coupling of linear wave theory and linear quasi-static consolidation theory. With the help of numerical modelling we solved corresponding equations considering also materially nonlinear consolidation. Within the scope of the research project the experimental and theoretical investigations will be validated. Therefore model tests in a model channel will be carried out under variation of H, L, h, and k. Occurring rearrangement processes in the submarine slopes will be simulated using two different discretization methods, namely FEM including a CEL algorithm, as well as SPH. The construction of a typical submarine slope for foundation of an offshore wind park at a chosen North Sea site will be simulated based on validated numerical models.

• DFG Programme: Research Grants