Numerical Modelling of Wind Turbine Foundations subjected to Combined Loading
Bibliographic record
Abstract
With the growing wind industry in Canada, it has become important to optimize wind turbine foundation design. Wind turbine foundations are subjected to combinations of vertical, horizontal and moment loads due to vertical self-weight of the structure and soil surcharge. Additionally, there are significant lateral loads and overturning moments attributed to varying wind forces acting at considerable tower heights above the ground level. In this thesis, the undrained bearing capacity response of circular & octagonal foundations subjected to combined loading is calculated using finite element analyses. Previous works have mostly focused on circular foundations. An octagonal foundation of the style typically used in the wind industry forms the focus of this research. Foundations are either surface based or embedded in homogeneous or heterogeneous soils. The results are expressed in terms of a coherent set of bearing capacity factors and failure envelopes in two dimensional planes (VH, VM and HM). This research also presents a parametric study on the effect of a surficial crust on the bearing capacity of a foundation. Finally, working and design loads for a typical wind turbine foundation are plotted in two dimensional failure planes to investigate if there is a potential `spare' capacity. The finite element study indicates that an increase in soil strength heterogeneity and embedment leads to increases in the uniaxial limit capacities and size of the failure envelopes. For octagonal foundations, the average increase in uniaxial vertical, horizontal and moment capacities due to increases in the embedment is 15%, 52% and 32% respectively. The average increase in uniaxial vertical and moment capacities due to increase in the soil strength heterogeneity is 7.1% and 6.7% respectively, for octagonal foundations. When the shape of a foundation changes from a circle to an octagon, the ultimate uniaxial vertical and moment capacities slightly increase (by 7.7% and 7.2% respectively). Under combined loading, conventional methods are found to underestimate the combinations of horizontal and moment loads that a foundation can resist safely. During eccentric loading, the effective area predicted using the method given by DNV (2002) is also under-predicted.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".