Experimental Study Of The Local Scour Around Different Shape Of Piles

Mustafa Awad Chetheer; Mohamad Alyounis; Saleh Issa Khassaf

doi:10.29284/39dqkz57

Authors

Mustafa Awad Chetheer Department of Civil Engineering Faculty of Engineering, University of Basrah, Basrah, Iraq
Mohamad Alyounis Department of Civil Engineering, Faculty of Engineering, University of Basrah, Basrah, Iraq
Saleh Issa Khassaf Department of Civil Engineering, Faculty of Engineering, University of Basrah, Basrah, Iraq

DOI:

https://doi.org/10.29284/39dqkz57

Keywords:

Pile shape, Scour depth, Dimensional Analysis

Abstract

This experimental study investigates the local scour phenomena around piles of different cross-sectional shapes—square, circular, and triangular—under controlled hydraulic conditions. The primary goal is to understand how the geometry of piles influences the depth and pattern of scour, which is critical for the stability and design of hydraulic structures. The results reveal that pile shape significantly affects scour characteristics. Triangular piles experience the deepest and most severe scour, with maximum depths reaching up to 5 meters near the pointed apex facing the flow. This is due to the sharp angle accelerating water velocity and creating strong vortices that enhance erosion. Circular piles exhibit a more uniform scour pattern with moderate maximum depths around 2.5 meters. Their rounded shape allows smoother flow around the pile, leading to widespread but less intense scour compared to the triangular piles. Square piles show intermediate scour depths, generally less severe than triangular piles but somewhat comparable to circular ones. The sharp corners of square piles create flow separations and vortices but tend to distribute scour more locally. Across all shapes, the highest scour occurs upstream near the pile front due to the formation of horseshoe vortices and accelerated flow. Downstream scour depths are generally lower because of flow deceleration and sediment deposition. These findings emphasize the importance of considering pile shape in the design of foundations to mitigate scour risks. Understanding scour behavior around different geometries helps engineers develop better scour protection measures and ensure the longevity of hydraulic structures.

References

1. Melville, B. W., & Chiew, Y. M. (1999). Time scale for local scour at bridge piers. Journal of Hydraulic Engineering, 125(1), 59–65.

2. Sheppard, D., & Sumer, B. M. (2018). Local scour around piles: A review. Coastal Engineering, 132, 137–151.

3. Chen, J., & Zhao, J. (2020). Experimental study on local scour around multiple piles in series. Water, 12(7), 2025.

4. Gray, D. H., & Weihs, H. (1991). Local scour at bridge piers and abutments. Journal of Hydraulic Engineering, 117(7), 749–769.

5. Ettema, R., & Muste, M. (2003). Sediment scour around bridge piers: Experimental study and modeling. Journal of Hydraulic Research, 41(1), 47–54.

6. Xie, Z., Wang, X., & Guo, Y. (2021). Effects of pile shape on local scour depth under clear-water conditions. Advances in Civil Engineering, 2021, Article ID 8856327.

7. Prakash, S., & Arora, S. (2019). Scour around piles: A state-of-the-art review. International Journal of Sediment Research, 34(2), 117–132.

8. Shimizu, Y., & Miyazaki, T. (2017). Influence of pile shape on local scour characteristics. Journal of Hydraulic Engineering, 143(5), 04017012.

9. Manes, C., & Nelson, J. (2018). Local scour prediction at pile groups. Journal of Hydraulic Research, 56(2), 180–192.

10. Zarrati, A., & Ghasemi, M. (2020). Experimental investigation of scour around square and circular piles under steady flow. Environmental Fluid Mechanics, 20(4), 913–927.

11. LaRocque, P. E., & Hay, A. E. (2016). Local scour dynamics in a sandy bed around piles. Coastal Engineering, 107, 84–96.

12. Thorne, C. R., & Shiono, K. (2016). Local scour around cylindrical structures. Water Resources Research, 52(6), 4553–4574.

13. Lee, J., & Kim, D. (2021). The effect of pile shape on scour development under unidirectional flow. Journal of Hydraulic Engineering, 147(3), 04021006.

14. García, M. H. (2008). Sedimentation engineering: Processes, measurements, modeling, and practice. ASCE Manuals and Reports on Engineering Practice No. 110.

15. Sumer, B. M., & Fredsøe, J. (2002). The mechanics of scour in the marine environment. Advanced Series on Ocean Engineering, Vol. 17, World Scientific.

16. Zhou, T., & Xu, Y. (2019). Local scour around piles in cohesive soils. Journal of Geotechnical and Geoenvironmental Engineering, 145(11), 04019070.

17. Yang, S., & Dai, S. (2022). Numerical and experimental study on scour around pile groups of different shapes. Water, 14(10), 1584.

18. Jafari, R., & Bahrami, M. (2017). Influence of pile cross-section on local scour in alluvial channels. River Research and Applications, 33(9), 1497–1507.

19. Baykal, G., & Ahmet, A. (2020). Experimental analysis of scour around bridge piles of different shapes. International Journal of Hydraulic Engineering, 9(3), 102–111.

20. Singh, V., & Patel, M. (2019). Scour depth around circular and square piles: An experimental study. International Journal of Sediment Research, 34(1), 56–67.

21. Fu, X., & Wu, W. (2021). Local scour around cylindrical and non-cylindrical piles: A comparative study. Environmental Fluid Mechanics, 21(5), 1207–1221.

22. Zhang, L., & Zhao, Q. (2018). Effects of flow turbulence on scour around bridge piles. Journal of Hydraulic Research, 56(1), 35–45.

23. Breusers, H. N. C., Nicollet, G., & Shen, H. W. (1977). Local scour around cylindrical piers. Journal of hydraulic research, 15(3), 211-252.

24. ‏ Breusers, H. N. C., & Raudkivi, A. J. (1991). Scouring. Rotterdam: Balkema.

25. Chiew, Y. M., & Melville, B. W. (1987). Local scour around bridge piers. Journal of hydraulic research, 25(1), 15-26.‏

26. Fredsoe, J., & Deigaard, R. (1992). Mechanics of coastal sediment transport (Vol. 3). World scientific publishing company.‏

27. Hoffmans, G. J. C. M., Van Hoven, A., Harderman, B., & Verheij, H. J. (2014). Erosion of grass covers at transitions and objects on dikes. In Scour and Erosion: Proceedings of the 7th International Conference on Scour and Erosion (pp. 643-649).‏

28. Lane, E. W. (1955). Design of stable channels. Transactions of the American society of Civil Engineers, 120(1), 1234-1260.‏

29. May, R. W. P., Ackers, J. C., & Kirby, A. M. (2002). Manual on scour at bridges and other hydraulic structures (Vol. 551). London, UK: Ciria.‏Melville, B.W. and Sutherland, A.J. (1988)

30. Richardson, E. V., & Davis, S. R. (2001). Evaluating scour at bridges (No. FHWA-NHI-01-001). United States. Federal Highway Administration. Office of Bridge Technology.‏

31. Roulund, A., Sumer, B. M., Fredsøe, J., & Michelsen, J. (2005). Numerical and experimental investigation of flow and scour around a circular pile. Journal of Fluid mechanics, 534, 351-401.‏

32. Sumer, B. M., Christiansen, N., & Fredsøe, J. (1997). The horseshoe vortex and vortex shedding around a vertical wall-mounted cylinder exposed to waves. Journal of Fluid Mechanics, 332, 41-70.‏

33. Whitehouse, R. J., & Mitchener, H. J. (1998). Observations of the morphodynamic behaviour of an intertidal mudflat at different timescales. Geological Society, London, Special Publications, 139(1), 255-271.‏

34. Rashak, B. M., & Khassaf, S. I. (2021). Study the local scour around different shapes of single submerged groyne. Journal of Water and Land Development, 48(1), 140–148.

35. Khassaf, S. I., & Obied, N. A. (2021). Experimental study for bridge pier protection against local scour by using guide panels. Faculty of Engineering, University of Basrah.