Abstract
Dams with core of broadly graded glacial moraines (tills) exhibit signs of internal erosion by suffusion to a larger extent than dams constructed with other types of materials, as reported by Sherard (1979). Garner and Fannin (2010) indicated that internal erosion initiates when an unfavorable combination of soil material, stress conditions and hydraulic load occur. A laboratory program, carried out at Luleå University of Technology (LTU), aims to study the effects of void ratio and hydraulic gradient on the initiation of suffusion of glacial till. It consists of suffusion tests conducted in permeameters with an inner diameter 101.6 mm and a height of 115 mm. Results show, as expected, that the hydraulic conductivity is lower with lower void ratio. Nevertheless, as the hydraulic gradient increases, the hydraulic conductivity reaches steady values. Changes in the hydraulic conductivity suggest variation in the initial void ratio due to detachment of the finer particles from the soil matrix. These fine particles start clogging the lower layers, therefore the rate of water flow decreases and so does the hydraulic conductivity. The hydraulic gradient for which the hydraulic conductivity reaches steady values is considered as the upper limit without suffusion evolved.
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References
ASTM D1557 (1998) Laboratory compaction characteristics of soil using modified effort (56,000 ft-lbf/ft3 (2,700 kN-m/m3)). Philadelphia, USA
Correia dos Santos R, Caldeira L (2017). Erosion behaviour of gap-graded soils due to upward flow. In: Proceedings of 25th meeting of the European working group on internal erosion in embankment dams and their foundation, Delft, pp 58–68
Cedergren H (1989) Seepage, drainage and flow nets, 3rd edn. A Wiley-Interscience Publication, Hoboken, p 465
Garner SJ, Fannin RJ (2010) Understanding internal erosion: a decade of research following a sinkhole event. Int J Hydropower Dams Aqua-Media Int 17(3):93–98
Hunter G, Fell R, Topham C (2012) Backward erosion piping: what are the chances of that? In: Proceedings of Australian National Committee on Large Dams, Perth
Kenney TC, Lau D (1985) Internal instability of granular filters. Can Geotech J Natl Res Counc Can 22(2):215–225
Kenney TC, Lau D (1986) Internal instability of granular filters: reply. Can Geotech J Natl Res Counc Can 23(3):420–423
Leroueil S, Le Bihan J-P, Sebalhi S, Alicescu V (2002) Hydraulic conductivity of compacted tills from northern Quebec. Can Geotech J 39(5):1039–1049
Li M, Fannin RJ (2008) Comparison of two criteria for internal stability of granular soil. Can Geotech J 45(9):1303–1309
Moffat R, Fannin RJ, Garner S (2011) Spatial and temporal progression of internal erosion in cohesionless soil. Can Geotech J 48:399–412
Rönnqvist H, Viklander P, Knutsson S (2017) Experimental investigation of suffusion in dam core soils of glacial till. ASTM Geotechn Test J 40(3):426–439
Sherard JL (1979) Sinkholes in dams of coarse, broadly graded soils. In: Proceedings of the 13th ICOLD Congress, India, vol II, pp 25–35
Svensk Energi – Swedenergy AB (2012) Kraftföretagens riktlinjer för dammsäkerhet (RIDAS), Avsnitt 7.2 Fyllningsdammar Tillämpningsvägledning, in Swedish (Hydropower companies guidelines for dam safety, Section 7.2 Filling Dams Implementation Guidance), Stockholm, Sweden
Wan CF (2006) Experimental investigations of piping erosion and suffusion of soils in embankment dams and their foundations. Dissertation, University of New South Wales, Sydney, Australia
Wan CF, Fell R (2008) Assessing the potential of internal instability and suffusion in embankment dams and their foundations. J Geotech Environ Eng ASCE 134(3):401–407
Watabe Y, Leroueil S, Le Bihan J-P (2000) Influence of compaction conditions on pore-size distribution and saturated hydraulic conductivity of a glacial till. Can Geotech J 37(6):1184–1194
Acknowledgements
This study was supported by the Swedish Hydropower Centre – SVC, which is highly appreciated. Acknowledgment is also expressed to Luleå University of Technology for additional financial support and for providing the laboratory facilities for the work.
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Silva, I., Viklander, P., Laue, J. (2019). Effects of Void Ratio and Hydraulic Gradient on Permeability and Suffusion of Glacial Till Cores. In: Bonelli, S., Jommi, C., Sterpi, D. (eds) Internal Erosion in Earthdams, Dikes and Levees. EWG-IE 2018. Lecture Notes in Civil Engineering , vol 17. Springer, Cham. https://doi.org/10.1007/978-3-319-99423-9_10
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