Skip to main content
SpringerLink
Log in

Effect of weep hole and cut-off wall on hydraulic gradient and uplift pressure under a diversion dam

  • Published:
Sādhanā Aims and scope Submit manuscript

Abstract

In hydraulic structures such as diversion or gravity dams constructed on a porous foundation, the difference in water levels between upstream and downstream results in water seepage through the porous soil under the dam. This seepage flow generates uplift pressure under the structure that may cause a crack on the concrete surface of the structure’s floor. In this condition, the exit gradient may exceed the critical value and cause the piping phenomenon. In this study, the effect of the weep hole and cut-off wall on the uplift pressure and the hydraulic gradient under a diversion dam was investigated experimentally and numerically. For this purpose, four weep holes (diameter = 1 cm) were embedded along the longitudinal axis of the stilling basin. The weep holes were examined in single and combined modes. The experiments were conducted in three upstream water heads of 10, 15, and 20 cm. The results showed that in terms of seepage losses, hydraulic gradient, and uplift pressure, the binary combinations of weep holes are better than the other modes. Among the binary combinations, the combination of the two closest weep holes to the dam toe (weep holes 1 and 2) had the most proper performance. In the supplementary experiments, a cut-off wall in two depths (10 and 15 cm) was placed at the dam heel in addition to the best modes of weep holes combination. Overall, the simultaneous use of cut-off wall (especially 15 cm) and weep holes improved the hydraulic condition of seepage phenomenon under the dam.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10

Similar content being viewed by others

Abbreviations

D :

diameter of weep hole

h 1 :

water head in upstream

h 1 :

water head in downstream

k x, k y :

soil hydraulic conductivity in x and y direction

l :

distance from dam toe

L :

length of stilling basin

Q exp :

experimental seepage flux

Q sim :

simulated seepage flux

∆h :

difference between h1 and h2

\( \varphi \) :

water potential in soil

\( \partial \) x, \( \partial \) y :

grid size in x and y direction

References

  1. Nagraj T S and Murthy B R S 1985 Prediction of the reconsolidation pressure and recompression index of soil. Geotech. Test. J. 8: 199–202

    Google Scholar 

  2. Zainal A K E 2011 The effect of cutoff wall angle on seepage under dams. J. Eng. 5: 1109–1131

    Google Scholar 

  3. El-Razek M A and Elela M M A 2002 Effect of drainage gallery dimensions on the uplift force of a gravity dam. J. Lowland Tech. Int. 4: 43–50

    Google Scholar 

  4. Chahar Bh R 2004 Determination of length of a horizontal drain in homogeneous earth dams. J. Irrig. Drain. Eng. 130: 530–536

    Article  Google Scholar 

  5. Da Silva J F 2005 Influence of the geometry of the drainage system and of the foundation anisotropy on the uplift pressures under concrete dams. In: 5 th Brazilian Symposium on Applications of Computational Mechanics in Geotechnical Engineering, Belo Horizonte, Brazil, pp. 165–174

  6. Chen Y, Zhou Ch and Zheng H 2008 A numerical solution to seepage problems with complex drainage systems. Comput. Geotech. 35: 383–393

    Article  Google Scholar 

  7. Pakbaz M S, Dardaei A and Salahshoor J 2009 Evaluation of performance of plastic concrete cutoff wall in Karkheh Dam using 3-D seepage analysis and actual measurement. J. Appl. Sci. 9: 724–730

    Article  Google Scholar 

  8. Sabbagh-Yazdi S R, Mastorakis N E and Bayat B 2007 Assessment and application of 3D Galerkin finite volume explicit solver for computation of seepage and uplift in dam foundation. Inter. J. Math. Mod. Meth. Appl. Sci. 1: 285–293

    Google Scholar 

  9. Yu H, Li Sh and Chen Ch 2009 Evaluation and rehabilitation of the seepage problems at the Fengman dam. Electron. J. Geotech. Eng. 14: 1–14

    Google Scholar 

  10. Azizi S, Salmasi F, Abbaspour A and Arvanaghi H 2012 Weep hole and cut-off effect in decreasing of uplift pressure (case study: Yusefkand Mahabad Diversion Dam). J. Civil. Eng. Urban. 2: 97–101

    Google Scholar 

  11. Mansuri B and Salmasi F 2013 Effect of horizontal drain length and cutoff wall on seepage and uplift Pressure in heterogeneous earth dam with numerical simulation. J. Civil. Eng. Urban. 3: 114–121

    Google Scholar 

  12. Obead I H, Al-Baghdadi H M and Hamad R 2014 Reducing the impact of uplift pressures on the base of a concrete dam by configuration of drainage holes (hypothetical case study). Civil. Environ. Res. 6: 120–131

    Google Scholar 

  13. Anonymous 2007 Seepage Modeling with Seep/W. An Engineering Methodology. Third edition: Geo-Slope International Ltd. Calgary, Alberta, Canada

  14. Salmasi F and Mansuri B 2016 Numerical investigation of underground drain radius, depth and location on uplift pressure reduction (case study: Tabriz diversion dam. Azarian J. Agric. 3: 58–65

    Google Scholar 

  15. Nasr R I, Zeydan B A, Bakry M F and Saloom M S 2003 Uplift pressure relief on lined canals using tile drains. Alexandria Eng. J. 42: 497–507

    Google Scholar 

  16. Nayeb Asadollah S, Aalianvari A and Hajialibeigi H 2018 Role of geological structures in seepage from Lar dam reservoir. Arab. J. Geosci. 11: 632

    Article  Google Scholar 

  17. Moharrami A, Moradi Gh, Hajialilue Bonab M, Katebi J and Moharrami Gh 2014 Performance of cut-off walls under hydraulic structures against uplift pressure and piping phenomenon. Geotech. Geol. Eng. 33: 95–103

    Article  Google Scholar 

  18. Uday A M and Hasan H M 2016 Optimal location of drainage gallery under gravity dam by using finite element method. Int. J. Multidiscip. Res. Mod. Educ. 2: 611–622

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Water Engineering, University of Zanjan, Zanjan, 45371-38791, Iran

    GHORBAN MAHTABI

  2. Department of Water Engineering, University of Tabriz, Tabriz, 51666-16471, Iran

    FARSHID TARAN

Authors
  1. GHORBAN MAHTABI
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. FARSHID TARAN
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to GHORBAN MAHTABI.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

MAHTABI, G., TARAN, F. Effect of weep hole and cut-off wall on hydraulic gradient and uplift pressure under a diversion dam. Sādhanā 44, 92 (2019). https://doi.org/10.1007/s12046-019-1083-3

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1007/s12046-019-1083-3

Keywords

Search

Navigation