Comportement thermo-hydro-mécanique des géomatériaux poreux : approches expérimentales et numériques
(2003)
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- Authors
- Supervisors
- Thimus, Jean-François
- Abstract
- Thermo-hydro-mechanical behaviour of porous geomaterial : experimental and numerical approch. Artificial Ground Freezing (AGF) is based upon a simple physical phenomenon : water phase change into ice. This phase modification is characterized by an increase in soils strength due to grain cementation by ice. This technique permits to consolidated the ground before excavation. Furthermore, ground freezing is also present in low temperature underground storage. In this case, the expected property is to avoid leakage into the ground. Volume variation caused by phase change can create a damage state in the frozen geomaterial. The first objective of this thesis is to study and analyze geomaterial thermo-hydro-mechanical behaviour around a freezing pipe. To reach this aim, a smaller physical model has been elaborated to realize thermal tests with radial propagation. Several tests have been executed on different geomaterials: Twente sand, Boom clay and Pierre de Caen. Material characteristics permit to realize a parametric study of geomaterial thermal behaviour. Distinctness is observed between frost and non frost susceptible material, following stratification orientation and between transitory and steady thermal state. The second objective of this work proposes to deepen knowledge about ice influence on frozen ground mechanical behaviour. In this case, a mechanical tests serie perform with non-destructive technique (ultrasonic waves) is used simultaneously while load application. The use of ultrasonic waves permits to evaluated damage state in geomaterial sample for a given stress and ice influence in the mechanical behaviour. This aspect is also estimated with a thermoelastic homogenization model. The study presents also some analytical and numerical calculations to evaluate temperature and stress profile in tested geomaterial. Thermal calculation takes into account the phase change. Numerical simulations take resolution method of Stefan problem (enthalpy and mobile front methods). Damage state of tested samples during thermal test is also discussed.
- Affiliations
Citations
Côté, H. (2003). Comportement thermo-hydro-mécanique des géomatériaux poreux : approches expérimentales et numériques. https://hdl.handle.net/2078.5/97415