Investigation of seepage, uplift forces and hydraulic gradient under hydraulic structures with different configurations of dual-cutoff walls

Document Type : Research Article


1 University of Tabriz-Water engineering department

2 University of Tabriz,,- Department of Water Engineering

3 Department of water engineering, Tabriz University, Tabriz, Iran.


In the design of hydraulic structures, cutoff walls are needed for the reduction of uplift force and exit hydraulic gradient. The upstream cutoff wall is used for the reduction of the uplift force and the downstream cutoff wall is used for the reduction of the exit hydraulic gradient. This study tends to numerically investigate the double-cutoff beneath the hydraulic structures with variation in their location, distance and depth. Governing equations with boundary conditions are solved using the finite element method (FEM). Results showed that if the downstream cutoff wall is deeper than the upstream cutoff wall, the resultant uplift force would be more than the uplift force without cutoff walls. With a constant value for hydraulic structures width (B), decreasing in the distance between two cutoffs (L), results in the reduction in uplift force. Increasing in impermeable depth (D) and reduction in B, yields lower uplift force. Increasing in downstream cutoff depth (d2) and L, results in reduction in exit hydraulic gradient (GR). When the two cutoffs are located in the end of the hydraulic structure, GR is lower than that when the downstream cutoff is located in L/B=0.33 and L/B=0.66 from the upstream cutoff. Comparison between the available analytical solutions for two equal ending cutoffs with FEM, showed that FEM could predict PC and GR with a maximum 5% error.


Main Subjects

[1] J. Abrishami, N. Vahhab Rajaee, Gravity concrete dams: design and construction, Published by Astan Quds Razavi, 2000 (In Persian).
[2] A. Shamsaii, Design and construction of storage dams, Iran University of Science and Technology, 2003 (In Persian).
[3] R. Ghobadian, A.F. Choghabaghi, S. Mohamadi, The Effect of cutoff curtain location on phreatic seepage line and seepage discharge by numerical finite volumes method, Caspian Journal of Applied Sciences Research, 2(8) (2013).
[4] M. Beirami, Water conveyance structures, Isfahan university Tecnology publication center, 2004, (In Persian).
[5] M. Yousefi, M. Parvizi, M. Sedghi–Asl, Laboratory Investigation the effects of sheet pile on seepage control and sand boiling through alluvial foundation of hydraulic structures, Amirkabir Jounrnal of Science & Research Civil and Enviromental Engineering (ASJR-CEE), 48(3) (2016) 121-123.
[6] H.F. Aghajani, M.M. Anzabi, Z. Sheikhi, R. Shokri, Selecting Optimum Cutoff Wall Position for Rehabilitation of an Inclined Core Earthfill Dam, in:  GeoShanghai International Conference, Springer, 2018, pp. 252-260.
[7] B. Nourani, F. Salmasi, A. Abbaspour, B. Oghti Bakhshayesh, Numerical investigation of the optimum location for vertical drains in gravity dams, Geotechnical and Geological Engineering, 35(2) (2017) 799-808.
[8] F. Salmasi, M. Nouri, Effect of upstream semi-impervious blanket of embankment dams on seepage, ISH Journal of Hydraulic Engineering, 25(2) (2019) 143-152.
[9] F. Salmasi, B. Mansuri, A. Raufi, Use of numerical simulation to measure the effect of relief wells for decreasing uplift in a homogeneous earth dam, Civil Engineering Infrastructures Journal, 48(1) (2015) 35-45.
[10] R. Norouzi, F. Salmasi, H. Arvanaghi, Effect of cut off wall on hydraulic gradient and seepage in the Sabalan rock fill dam by numerical simulation, Hydrogeology, 2(1) (2017) 71-84 (In Persian).
[11] F. Salmasi, R. Norouzi, J. Abraham, B. Nourani, S. Samadi, Effect of Inclined Clay Core on Embankment Dam Seepage and Stability Through LEM and FEM, Geotechnical and Geological Engineering, 38(6) (2020) 6571-6586,
[12] F. Salmasi, B. Nourani, J. Abraham, R. Norouzi, Numerical investigation of relief well performance for decreasing uplift pressure under embankment dams, International Journal of Environmental Science and Technology,  18, 2819–2830 (2021),
[13] A.K. Jain, L.N. Reddi, Finite-depth seepage below flat aprons with equal end cutoffs, Journal of Hydraulic Engineering, 137(12) (2011) 1659-1667.