Développement d'une cellule de conductivité hydraulique permettant d'évaluer l'anisotropie des tills compactés du nord québécois
|Abstract:||Compacted tills are widely use as core of embankment dams in northern Quebec. It is expected that placement method in successive layers may result in a permeability anisotropy different from unity. Various experimental techniques are available to assess the permeability anisotropy for different types of materials. However, these methods have two principal disadvantages: i) the anisotropy rapport is evaluated on separate samples and ii) the experimental procedure could potentially disturb the sample by inappropriate manipulations. In order to improve the characterization of the anisotropy rapport of compacted tills, a new square cell was built. This new cell is able to quantify the anisotropy rapport in both states, saturated and almost saturated conditions. The permeability under vertical and horizontal flow is assessed on a single sample and a new experimental procedure has been developed to minimize preferential seepage paths along the porous stones. Injection of bovine gelatin is used to temporarily seal the porous stones perpendicular to the flow path (unused). Continuous hot water flow is used to extract the gelatin once the permeability testing is done. This new device and procedure have been successfully tested to evaluate the effect of placing method and stone content on the permeability anisotropy of compacted tills. For an analysis in quasi-saturated state, the anisotropy rapport is greater than 3 or 7 for a dry compaction. On the wet side, the anisotropy rapport is close to one. However, the procedure developed in the saturated condition should be used to confirm these results. In conclusion, this project has helped to build a useful tool to quantify the anisotropy rapport of tills, an important issue in the evaluation of embankment dams. Key words: permeability, anisotropy, square permeability cell, compacted tills, embankment dam.|
|Document Type:||Mémoire de maîtrise|
|Open Access Date:||16 April 2018|
|Collection:||Thèses et mémoires|
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