Hydraulic fracturing (HF) in a dam is the phenomenon of crack propagation after water pressure enters and expands an existing crack. An HF numerical model was tested on an existing dam on a complex foliated rock foundations. The locations and areas of HF could be identified, leading to the development of the hydraulic fracturing index (HFI). The results revealed that the HF area mainly occurred in syncline concave areas on rock foundations. The expansion of HF significantly affected the seepage and the stability of the dam. The HF area on a studied dam mainly started to occur when the reservoir water level (RWL) reached 146.00–156.00 m mean sea level (MSL). These results agreed well with the piezometric monitoring data recorded as 148.00–149.00 m MSL. The findings supported the formulation of the HFI based on the influencing factors of the cross-valley geometry, RWL, dam height, and elastic modulus of the rock foundation. The probability of HF occurrence could be evaluated and categorized for safety evaluation into five conditions: ≤0.14 (very unlikely), 0.15–0.74 (unlikely), 0.75–1.86 (neutral), 1.87–3.10 (likely), and ≥3.10 (very likely). The HFI can be used to predict the likelihood of seepage problems due to HF in an existing earth dam.

1. [1] J.-J. Wang, “Hydraulic Fracturing in Earth-Rock Fill Dams,” John Wiley & Sons, 2014.
2. [2] M. Salari, A. Akhtarpour, and A. Ekramifard, “Hydraulic Fracturing: A Main Cause of Initiating Internal Erosion in a High Earth-Rock Fill Dam,” Int. J. of Geotechnical Engineering, Vol.15, No.2, pp. 207-219, 2021.
3. [3] J. L. Sherard, “Hydraulic Fracturing in Embankment Dams,” J. of Geotechnical Engineering, Vol.112, No.10, pp. 905-927, 1986.
4. [4] F. Ye, J.-C. Duan, W.-X. Fu, and X.-Y. Yuan, “Permeability Properties of Jointed Rock with Periodic Partially Filled Fractures,” Geofluids, Vol.2019, 4039024, 2019.
5. [5] H. B. Seed, T. M. Leps, J. M. Duncan, and R. E. Bieber, “Appendix D: Hydraulic Fracturing and its Possible Role in the Teton Dam Failure,” Independent Panel to Review Cause of Teton Dam Failure, “Report to U.S. Department of the Interior and State of Idaho on Failure of Teton Dam,” pp. D-1-D-39, U.S. Government Printing Office, 1976.
6. [6] P. R. Vaughan, D. J. Kluth, M. W. Leonard, and H. M. M. Pradoura, “Cracking and Erosion of the Rolled Clay Core of Balderhead Dam and the Remedial Works Adopted for its Repair,” Trans. of 10th Int. Congress on Large Dams, pp. 73-93, 1970.
7. [7] A. K. L. Ng and J. C. Small, “A Case Study of Hydraulic Fracturing Using Finite Element Methods,” Canadian Geotechnical J., Vol.36, No.5, pp. 861-875, 1999.
8. [8] S. M. Haeri and D. Faghihi, “Predicting Hydraulic Fracturing in Hyttejuvet Dam,” 6th Int. Conf. on Case Histories in Geotechnical Engineering, 40, 2008.
9. [9] D.-J. Yu, M.-J. Yoon, K.-W. Park, and J.-H. Cho, “Stability Evaluation Case of Hydraulic Fracturing in Center Core Rockfill Dam Using Stress-Deformation Analysis by FEM (Xe-Pian/Xe-Namnoy Dam in Laos),” Yooshin Technical Bulletin, Vol.22, pp. 193-207, 2015.
10. [10] D. Yilmaz, A. C. Altunisik, and S. Adanur, “Deformation Modulus of Rock Foundation in Deriner Arch Dam,” Geomechanics and Engineering, Vol.26, No.1, pp. 63-75, 2021.
11. [11] M. Talebi, F. Vahedifard, and C. L. Meehan, “Effect of Geomechanical and Geometrical Factors on Soil Arching in Zoned Embankment Dams,” Geo-Congress 2013: Stability and Performance of Slopes and Embankments III, pp. 1056-1065, 2013.
12. [12] A. Soroush and M. Pourakbar, “Evaluation of Low Stress and Cracking Zones in the Core of a High Rockfill Dam in a Relatively Narrow Canyon Using 3D Numerical Modeling,” Int. J. of Geomechanics, Vol.22, No.3, 04021299, 2022.
13. [13] J.-G. Zhu and J.-J. Wang, “Investigation to Arcing Action and Hydraulic Fracturing of Core Rock-Fill Dam,” Proc. of the 4th Int. Conf. on Dam Engineering – New Developments in Dam Engineering, pp. 1171-1180, 2004.
14. [14] M. Komasi and B. Beiranvand, “Study of Hydraulic Failure Mechanism in the Core of Eyvashan Earth Dam with the Effect of Pore Water Pressure and Arching,” J. of Stress Analysis, Vol.4, No.2, pp. 55-67, 2020.
15. [15] P. Talukdar and A. Dey, “Finite Element Analysis for Identifying Locations of Cracking and Hydraulic Fracturing in Homogeneous Earthen Dams,” Int. J. of Geo-Engineering, Vol.12, No.1, 10, 2021.
16. [16] T. Fujiyama, T. Ishiguro, Y. Uchita, and H. Ohta, “Elasto-Plastic FEM Analysis and Safety Evaluation of Large Rockfill Dams During Reservoir Filling,” J. Chu, S. P. R. Wardani, and A. Iizuka (Eds.), “Geotechnical Predictions and Practice in Dealing with Geohazards,” pp. 131-147, Springer, 2013.
17. [17] D. K. McCook and K. O. Grotrian, “Using SIGMA/W to Predict Hydraulic Fracture in an Earthen Embankment,” Proc. of the Association of State Dam Safety Officials (ASDSO) Annual Conf., pp. 247-271, 2010.
18. [18] R. Fell et al., “Risk Analysis for Dam Safety: A Unified Method for Estimating Probabilities of Failure of Embankment Dams by Internal erosion and Piping Guidance Document (Version: Delta),” UNICIV Report R 446, University of New South Wales, 2009.
19. [19] M. Rashidi and S. M. Haeri, “Evaluation of Behaviors of Earth and Rockfill Dams During Construction and Initial Impounding Using Instrumentation Data and Numerical Modeling,” J. of Rock Mechanics and Geotechnical Engineering, Vol.9, No.4, pp. 709-725, 2017.
20. [20] E. S. Nobari and J. M. Duncan, “Effect of Reservoir Filling on Stresses and Movements in Earth and Rockfill Dams: A Report of an Investigation,” College of Engineering, University of California, Berkeley, 1972.
21. [21] H. Ohta, A. Takahashi, Y. Mori, T. Ishiguro, and T. Fujiyama, “Safety of Large Rockfill Dams During Reservoir Filling,” Proc. of 22nd Int. Congress on Large Dams, pp. 719-740, 2006.
22. [22] R. Fell, C. F. Wan, and M. A. Foster, “Assessment of the Likelihood of Initiation of Erosion in Embankment Dams,” R. Fell and J.-J. Fry (Eds.), “Internal Erosion of Dams and Their Foundation,” pp. 71-102, CRC Press, 2007.
23. [23] D. Djarwadi, K. B. Suryolelono, B. Suhendro, and H. C. Hardiyatmo, “Effect of Clay Core Configuration of the Rock Fill Dams Against Hydraulic Fracturing,” Procedia Engineering, Vol.171, pp. 492-501, 2017.
24. [24] Department of Mineral Resources, “Geological Map of Uttaradit,” 2007.
25. [25] S. Singharajwarapan and R. Berry, “Tectonic Implications of the Nan Suture Zone and its Relationship to the Sukhothai Fold Belt, Northern Thailand,” J. of Asian Earth Sciences, Vol.18, No.6, pp. 663-673, 2000.
26. [26] Geotechnical Engineering Research and Development Center, “Semi-Quantitative Risk Assessment on Stability of Saddle Dikes of Sirikit Dam (Final Report),” Electricity Generating Authority of Thailand, 2019 (in Thai).
27. [27] U.S. Department of the Interior Bureau of Reclamation and U.S. Army Corps of Engineers, “Best Practices in Dam and Levee Safety Risk Analysis,” Version 4.1, 2019. https://www.usbr.gov/ssle/damsafety/risk/methodology.html [Accessed November 23, 2022]
28. [28] Department of the Army, U.S. Army Corps of Engineers, “Safety of Dams – Policy and Procedures,” ER 1110-2-1156, 2014.
29. [29] Interagency Committee on Dam Safety (ICODS), Federal Emergency Management Agency (FEMA), “Evaluation and Monitoring of Seepage and Internal Erosion,” FEMA P-1032, 2015.
30. [30] T. A. Feyissa and N. G. Tukura, “Evaluation of the Best-Fit Probability of Distribution and Return Periods of River Discharge Peaks. Case Study: Awetu River, Jimma, Ethiopia,” J. of Sedimentary Environments, Vol.4, No.4, pp. 361-368, 2019.
31. [31] G. Heo, “Unified Method of Estimating the Probability of Failure of an Embankment Dam Due to Internal Erosion by Expert Survey and Event Tree Analysis,” Ph.D. thesis, Seoul National University, 2019.
32. [32] D. Komori et al., “Application of the Probability Evaluation for the Seasonal Reservoir Operation on Flood Mitigation and Water Supply in the Chao Phraya River Watershed, Thailand,” J. Disaster Res., Vol.8, No.3, pp. 432-446, 2013.
33. [33] S. G. Vick, “Degrees of Belief: Subjective Probability and Engineering Judgment,” American Society of Civil Engineers (ASCE) Press, 2002.
34. [34] W. Saejiaw, “Diagnosis Expert System for Seepage Problems Through Medium and Small Scale Dam: Case Study Sirikit Saddle Dam,” Ph.D. thesis, Kasetsart University, 2022 (in Thai).