Ageing of cement grouted joint by water and acidic flows for assessing dam foundation quality

Nicolas Néron, Patrice Rivard

In the proceedings of: GeoSt. John's 2019: 72nd Canadian Geotechnical Conference

Session: Rock Mechanics

ABSTRACT: Cement grouting is widely used to maintain the safety of dams by reducing the water pressure in rock foundations and by improving its quality. However, little is known about the ageing of grouted joints. Some studies have suggested that erosion and dissolution caused by water flow are the main factors of degradation. This paper deals with a laboratory study assessing the performance of cement grout injection in rock or mortar test samples and submitted to a constant water (or acid) flow. Each sample was kept in a sealed box where a pump induced a flow at constant pressure. The degradation time ranged from two weeks to two months. The main decrease occurred on the cement grout surface, showing a modification on Barton's JRC and a global variation of the shear strength indeed. Finally, the study adds a new dimension to the grout degradation of dams, which offer an accelerated system of deterioration by flow.

RÉSUMÉ: Le coulis de ciment est largement utilisé pour maintenir la sécurité des barrages en réduisant la pression d'eau dans les fondations rocheuses et en améliorant sa qualité. Cependant, on sait peu de choses sur le vieillissement des joints. Certaines études ont suggéré que l'érosion et la dissolution causées par l'écoulement de l'eau sont les principaux facteurs de dégradation. Cet article constitue une étude en laboratoire évaluant la performance d'injections de coulis de ciment sur des échantillons de roche ou de mortier qui sont soumis à un écoulement constant d'eau ou d'acide. Chaque échantillon a été conservé dans un boitier étanche où une pompe induisait un débit à pression constante. Le temps de dégradation variait de deux semaines à deux mois. La principale diminution a eu lieu à la surface du coulis de ciment, montrant une modidimension à la dégradation du coulis des barrages, qui offre un système accéléré de détérioration par écoulement.

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Cite this article:
Nicolas Néron; Patrice Rivard (2019) Ageing of cement grouted joint by water and acidic flows for assessing dam foundation quality in GEO2019. Ottawa, Ontario: Canadian Geotechnical Society.

@article{Geo2019Paper235,author = Nicolas Néron; Patrice Rivard,title = Ageing of cement grouted joint by water and acidic flows for assessing dam foundation quality ,year = 2019}