One- and two-dimensional finite element modelling of thaw consolidation

2021 ◽  
Author(s):  
Rajith Sudilan Dayarathne ◽  
Bipul C. Hawlader ◽  
Ryan Phillips ◽  
Dilan Robert
Keyword(s):  
Finite Element ◽  
Hydraulic Conductivity ◽  
Void Ratio ◽  
Soil Column ◽  
Nonlinear Behaviour ◽  
Two Dimensional ◽  
Fe Modelling ◽  
Rapid Reduction ◽  
Thaw Consolidation ◽  
Dimensional Finite Element

Coupled thermo-hydro-mechanical finite element (FE) modelling of thaw consolidation is presented. One-dimensional FE analyses are performed for thaw consolidation of a soil column due to self-weight and with a combination of self-weight and surcharge, with the linear and nonlinear void ratio–effective stress–hydraulic conductivity relationships of thawed soil. The nonlinear behaviour of thawed soil is modelled using a modified Drucker–Prager Cap model, while the hydraulic conductivity is varied with the void ratio. Finally, two-dimensional FE modelling of thaw consolidation around a warm pipeline buried in permafrost is performed. The rapid reduction of the void ratio with consolidation, especially at the low-stress level, results in a wide variation of hydraulic conductivity within the thawed zone. The significantly large hydraulic conductivity of soil elements along the curved thaw front, as compared to that of thaw consolidated soil, causes the flow of water along the thaw front, instead of a vertical flow, as assumed in previous 1-D thaw consolidation modelling of buried pipelines.

Exact analysis of the bending of wide beams by a modified elastica approach

2011 ◽  
Vol 225 (11) ◽  
pp. 2759-2764 ◽  
Author(s):  
L F Campanile ◽  
R Jähne ◽  
A Hasse
Keyword(s):  
Finite Element ◽  
Substantial Reduction ◽  
Short Review ◽  
Computational Effort ◽  
Two Dimensional ◽  
Finite Element Calculations ◽  
Dimensional Finite Element ◽  
Wide Beams ◽  
Insight Into ◽  
Selection Of

Classical beam models do not account for partial restraint of anticlastic bending and are therefore inherently inaccurate. This article proposes a modification of the exact Bernoulli–Euler equation which allows for an exact prediction of the beam's deflection without the need of two-dimensional finite element calculations. This approach offers a substantial reduction in the computational effort, especially when coupled with a fast-solving schema like the circle-arc method. Besides the description of the new method and its validation, this article offers an insight into the somewhat disregarded topic of anticlastic bending by a short review of the published theories and a selection of representative numerical results.

Modélisation hydrodynamique du lac Saint-Pierre, fleuve Saint-Laurent : l'influence de la végétation aquatique

1994 ◽  
Vol 21 (3) ◽  
pp. 471-489 ◽  
Author(s):  
Paul Boudreau ◽  
Michel Leclerc ◽  
Guy R. Fortin
Keyword(s):  
Finite Element ◽  
Aquatic Plants ◽  
Mathematical Formulation ◽  
Substantial Effect ◽  
Data Sets ◽  
Two Dimensional ◽  
Field Surveys ◽  
Dimensional Finite Element ◽  
Modelling Simulation ◽  
St Lawrence River

The macrophytes (aquatic plants) can have a substantial effect on the hydrodynamics of some watercourses. A mathematical formulation for the resistance effect of macrophytes on the current is inserted in a two-dimensional finite element hydrodynamic model. The method introduced herein allows to take into account the morphology, the density, and the growth curve of the different species of macrophytes present in the river. The Lake Saint-Pierre between Sorel and Trois-Rivières (Québec, Canada) in the St. Lawrence River is used to demonstrate the approach. The mathematical aspect of the model is first briefly presented. The field surveys of macrophytes and some other data sets used with the model are then analyzed. Finally, after the calibration–validation step, which insures the good behavior of the model, some results are presented to show the effect of the macrophytes on the flow structure. Key words: hydrodynamics, aquatic plants, St. Lawrence River, Lake Saint-Pierre, two-dimensional modelling, simulation, finite element method, Manning's coefficient.

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