Numerical modelling and InSAR monitoring of settlement in \nChamplain clays
Notice bibliographique
Résumé
The presence of Champlain clay deposits in vast areas of eastern Canada brings a higher probability of geotechnical hazards in this region. Soil settlement is one of the geotechnical hazards that is believed to be strongly correlated to the presence of Champlain clays. High compressibility and significant soil moisture changes are two key elements involved in settlement of Champlain clays. Land subsidence in fine-grained soil is often caused by an excessive pore pressure decline. Numerical modelling of the pore pressure within clay aquitards can thus provide valuable information on the causes and progress of settlement. \n \nThe pore pressure fluctuations measured in deep aquitards are also correlated to moisture loading above it. Analyzing the pore pressure record corrected for barometric and Earth tide effects allows this correlation to be quantified. This relationship is more complex in shallow aquitards due to their stronger interactions with the surrounding environment. Seasonal fluctuations of the water table are an example of these interactions. These fluctuations induce pore pressure changes through transient flow. In the first part of this thesis, a finite-element model (FEM) was developed with COMSOL Multiphysics. The model simulates the pore pressure changes within a saturated Champlain clay aquitard using a coupled flow-deformation model. A MATLAB script was also prepared for the MATLAB LiveLink interface in COMSOL based on a series of hydrological equations. The MATLAB script iterates step-bystep on a total stress boundary conditions to replicate the pore pressure time series obtained in the field. These data were obtained from the Sainte-Marthe test site near Montreal, Canada. \n \nThe second part of this thesis is dedicated to InSAR monitoring and numerical modelling of settlement. It investigates the vertical ground movements between May 2017 and December 2019 on the test site using numerical modelling and the Persistent Scatterer InSAR (PSI) technique. In this regard, a model based on the finite element method (FEM) and Biot's poroelasticity theory was developed. The model estimates soil settlement and expansion using pore pressure measurements in the bedrock and fractured clay layer, and temperature obtained from a study site in Sainte-Marthe, Quebec. The model is capable of addressing the deformation separately in a hydraulically more active superficial top layer and deeper intact clay layer. To monitor the settlement at the study site, vertical displacements were calculated at a larger scale in the Vaudreuil-Soulanges region with the PSI technique using SARPROZ with linear and non-linear approaches. \n \nThe last part of this thesis deals with the monitoring of settlement on Montreal Island between April 2016 and April 2022. The displacement velocity was monitored using the PSI method and a linear technique all over the Montreal Island. The aim of this monitoring was to detect the main areas with large settlements on Montreal Island. The results in this thesis can be grouped in three parts. The results for the first part of this thesis dealt with numerical modelling of the pore pressure changes. These results showed that the model can reproduce the historical pore pressure time series reasonably well. Implementation of the MATLAB script could significantly improve the optimization results. Concerning the numerical modelling of settlement in the second part of the thesis, the results show a reasonable agreement between the FEM simulations and PSI estimates. A seasonal trend of displacement with a maximum range of 15 mm was estimated. Subsidence as large as 55 mm was estimated by the FEM model and non-linear PSI approach over a period of 30 months. Non-linear PSI could detect the non-linear displacement of the soil more effectively. The displacement velocity was -9 mm/year for the non-linear method compared to -8 mm/year for the FEM estimation. The long-term monitoring of the settlement on Montreal Island revealed that serious settlements up to -10 mm/year are in progress in certain areas of the Montreal Island. The continuous progress of settlement in this region might be induced by a decrease in the soil water moisture associated with the effect of climate change.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,001 |
| Méta-épidémiologie (sens large) | 0,002 | 0,000 |
| Bibliométrie | 0,000 | 0,002 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,002 | 0,002 |
| Intégrité de la recherche | 0,003 | 0,003 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; les deux têtes enseignantes s’accordent sur ce qui est montré ici.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».