Use of Numerical Simulation to Measure the Effect of Relief Wells for Decreasing Uplift in a Homogeneous Earth Dam

Document Type: Research Papers

Authors

1 Water Engineering Department, Faculty of Agriculture, University of Tabriz, Tabriz, Iran.

2 M.Sc. Student of Hydraulic Structures, University of Tabriz, Tabriz, Iran

3 M.Sc. Student of Hydraulic Structures, University of Azad Ahar, Ahar, Iran.

Abstract

Relief wells are used extensively to relieve excess hydrostatic pressure in pervious foundation strata overlain by impervious top strata, conditions which often exist landward of levees and downstream of dams and hydraulic structures. Placing well outlets in below-surface trenches or collector pipes helps dry up seepage areas downstream of levees and dams. Relief wells are often used in combination with seepage control measures, such as upstream blankets, downstream seepage berms, and grouting. Draining seepage water into relief wells decreases uplift and prevents piping. This study examined the effect of relief wells with different diameters at different distances downstream of a homogeneous earth dam using Seep/W software. Also the effect of upstream water level of reservoir on seepage flow to each well was carried out. Results show that by decreasing the distance between relief wells and increasing the diameter of the relief wells, total uplift pressure decreases. The optimum distance between relief wells to decrease uplift pressure was found to be 5 m. The proposed method is recommended in designing relief wells by providing optimum diameter and distance of wells for the sustained yield.

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Chen, Y., Yeh, H. and Yang, S. (2009). ”Analytical solutions for constant-flux and constant-head tests at a finite-diameter well in a wedge-shaped aquifer”, J. Hydraululic Engineering, 135(4), 333–337.
Davidson, G., Rigby, J., Pennington, D. and Cizdziel, J. (2013). “Elemental chemistry of sand-boil discharge used to trace variable pathways of seepage beneath levees during the 2011 Mississippi river flood”, Applied Geochemistry, 28(1), 62-68.
Gebhart, L.R. (1973). “Foundation seepage control option for existing dams”, American Society of Civil Engineers, Inspections, Maintenance and Rehabilitation of Old Dams, Proceedings of Engineering Foundation Conference in Washington, 660-674.
Geibel, N.M. (2004). “Rehabilitation of a bio-fouled pressure-relief well network, Garrison dam, North Dakota”, Environmental and Engineering Geoscience, 10(1), 175-183.
Geo-Studio. (2007). User guide, Seepage modeling with SEEP/W, An engineering methodology, Third Edition, GEO-SLOPE International Ltd.
Mansur, C., Postol, G. and Salley, J. (2000). “Performance of relief well systems along Mississippi river levees”, Journal of Geotechnical and Geo-Environmental Engineering, 126(8), 727–738.
Mathias, S., Butler, A. and Zhan, H. (2008). ”Approximate solutions for Forchheimer flow to a well”, Journal of Hydraulic Engineering, 134(9), 1318–1325.
Middlebrooks, T.A. and Jervis, W.H., (1997). “Relief wells for dams and levees”, Journal of Hydraulic Engineering, ASCE, 112(2), 1323-1336.

Mishra, G. and Majumdar, P. (2010). ”Unsteady solution for well recharge in a low diffusive aquifer”, Journal of Irrigation and Drainage Engineering, 136(12), 870–875.
Ozkan, S., Adrian, D., Sills, G. and Singh, V. (2008). Transient head development due to flood induced seepage under levees”, Journal of Geotechnical and Geo-Environmental Engineering, 134(6), 781-789.
Parks, S.A., (2012). Seepage and stability of a dam in an artesian setting, M.Sc. Thesis, Graduate College at the University of Nebraska.
Patel, H., Eldho, T. and Rastogi, A., (2010). ”Simulation of radial collector well in shallow alluvial riverbed aquifer using analytic element method”, Journal of Irrigation and Drainage Engineering, 136(2), 107–119.
Salama, R., Ali, R., Pollock, D., Rutherford, J. and Baker, V. (2003). Management and structure review, Department of Environmental Protection, A Report to Water and Rivers Commission, Minister for Environment, Western Australia.
USACE, US Army Corps of Engineers. (1992). Design, construction, and maintenance of relief wells, Washington, D.C., 20314-1000, EM11102-1914. 29.
Van Der Heijde, P.K., Huyakorn, P.S. and Merecer, J.W., (1984). “Testing and validation of groundwater models”, Proceedings of Practical Application of Groundwater Modeling, NWWA/IGWMC Conference, Columbus, OH, USA.
Vashisht, A. and Shakya, S., (2013). ”Hydraulics of a drainage well fully penetrating a leaky aquifer through a multisection screen”, Journal of Hydraulic Engineering, 139(12), 1258–1264.
Woyshner, M.R. and Yanful, E.K., (1995). “Modeling and field measurements of water percolation through an experimental soil cover on mine tailings”, Canadian Geotechnical Journal, 32(1), 601-609.
Yang, S., Huang, C., Liu, C. and Yeh, H. (2014). ”Approximate solution for a transient hydraulic head distribution induced by a constant-head test at a partially penetrating well in a two-zone confined aquifer”, Journal of Hydraulic Engineering, 140(7), 401-403.