Abstract
This paper presents a case history detailing the development of cracks within a rock mass up to 350 m from the steeply incised valley slopes of the Yalong river in South West China, where the Jinping I dam is being constructed. The cracks have opened along previous tectonic structural features such that they penetrate further into the rock mass in the metasandstones and slates than in the marble. The presence of these cracks significantly reduces the stability of the near surface rock mass, requiring major excavation at the dam abutment. Analysis has indicated that the most appropriate way of stabilizing the slopes before the dam is constructed is by grout-infilled, specially constructed galleries which extend 60–80 m from the freshly excavated abutment.
Résumé
L’article présente une étude de cas détaillant le développement de fissures au sein d’un massif rocheux jusqu’à 350 m à l’intérieur de versants raides, façonnés par la rivière Yalong dans le sud-ouest de la Chine où le barrage de Jinping I est en cours de construction. Les fissures se sont ouvertes le long de discontinuités structurales préexistantes, se propageant au-delà dans des grès métamorphiques, des ardoises et des marbres. La présence de ces fissures réduit de façon significative les conditions de stabilité du massif rocheux près de la surface, nécessitant un approfondissement des excavations pour les fondations du barrage. L’analyse a montré que la façon la plus appropriée pour stabiliser les pentes, avant la construction du barrage, était de procéder à des injections de coulis jusqu’à 60–80 m depuis l’appui rocheux excavé, à partir de galeries spécialement construites.
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Acknowledgments
The authors are grateful for the financial support from the China Natural Science Foundation under the grant of No. 40772188 and Chinese Academy of Sciences under grant of KZCX2-YW-109-2.
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Qi, S., Wu, F., Zhou, Y. et al. Influence of deep seated discontinuities on the left slope of Jinping I Hydropower Station and its stability analysis. Bull Eng Geol Environ 69, 333–342 (2010). https://doi.org/10.1007/s10064-010-0268-0
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DOI: https://doi.org/10.1007/s10064-010-0268-0