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

Document Type : Research Article

Authors

1 University of Tabriz-Water engineering department

2 University of Tabriz,,- Department of Water Engineering

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

Abstract

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.

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Main Subjects

References

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Amirkabir Journal of Civil Engineering
Volume 54, Issue 4
July 2022
Pages 1631-1650

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