Stability of artificial subaqueous slopes in sandy soils

在海上条件下建造海底人工坑时，应考虑到由于水动力作用（如水流、波浪、地震）的影响，长期边坡倾角小于陆上。我们的研究项目集中在非粘性土壤（侵蚀，沉积，破裂破坏，液化破坏）中海底边坡几何形状的变化，这是由于表面波引起的超孔隙水压力导致有效应力的减少，并且在海底边坡的情况下，根据波长L，波高H，水深H和土壤渗透率k，边坡几何形状会发生变化。在前期工作中，我们基于线性波动理论和线性准静力固结理论的耦合研究了这一过程。在数值模拟的帮助下，求解了考虑材料非线性固结的相应方程。在研究项目的范围内，实验和理论研究将得到验证。因此，将在H、L、H和k的变化下，在模型通道中进行模型试验。将使用两种不同的离散化方法，即包含CEL算法的FEM和SPH来模拟海底斜坡中发生的重排过程。本文将基于已验证的数值模型，对选定的北海海上风电场基础的典型海底斜坡的施工进行模拟。

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.