Study of Hydraulic Failure Mechanism in the Core of Eyvashan Earth Dam with the Effect of Pore Water Pressure and Arching

Document Type: Original Article

Authors

Civil Engineering Department, Water and Hydraulic Structures, University of Ayatollah ozma Borujerdi, Lorestan, Iran.

10.22084/jrstan.2020.20022.1110

Abstract

Continuous investigation and measurement of pore water pressure and arching depression play an important role in detecting the occurrence of hydraulic failure in earth dams. Increasing the pore water pressure during the initial impounding period reduces the effective stress and consequently decreases the shear strength of the earth dam core, which can overcome the water stress over the effective stress and consequently hydraulic failure. This research studies the hydraulic failure of Eyvashan earth dam under static loading conditions at the end of construction and the initial impounding period by Geostudio software with the Mohr-Coulomb behavioral model. The analysis shows that the values of the pore water pressure ratio (ru) and stress-strain values are acceptable and there is no stability problem for the dam. The highest percentage of arching (the lowest ratio of arching) is equal to 46%, at one-third of the lower height of the core. The critical arching ratio (maximum) is 0.44 and is in the normal range and hydraulic failure does not not occur despite the critical arching in the dam core.

Keywords


[1] B. Lofquist, Discussion of cracking in dams, In: Proceedings 5th ICOLD Congress Paris, Vol. III, (1957) 21-22.
[2] J.L. Sherard, Hydraulic fracturing in embankment dam, J. Geotech. Eng., 112(10) (1986) 905-927.
[3] M. Maksimovic, Optimal Position of Central Clay Core of Rock-Fill Dam with Respect to Arching and Hydraulic Fracture, International Congress on Large Dam, (1973) 789-800.
[4] F.H. Kulhawy,T.M. Gurtowski, load transfer and hydraulic fracturing in Zoned Dams, J. Geotech. Eng. Div., 102(9) (1976) 963-967.
[5] J.J. Wang, J.G. Zhu, H. Mroueh, C.F.Chiu, Hydraulic fracturing of rock-fill dam, J. Multiphasic, 1(2) (2007) 199-219.
[6] K. Soga, M.Y.A. Ng, K. Gafar, Soil Fractures in Grouting. In: Barla, G., Barla, M. (Eds.), Proc. 11th International Conference of the International Association of Computer Methods and Advances in Geomechanics, Prediction, Analysis and Design in Geomechanical Applications. Tornio, Italy, (2005).
[7] H. Satoh, Y. Yamaguchi, Laboratory hydraulic fracturing tests for core materials using large size hollow cylindrical specimens, The 1st International
Symposium on Rock-fill Dams, (2009).
[8] M.R. Mansoojian, M.R. Esmaeili, A. Kohzadian, Investigation of Hydraulic Failure in earth Dams and Structures Using SIGMA/W Software, 5th National Conference on Irrigation and Drainage Networks Management and Third Iranian National Irrigation and Drainage Congress, (2017).
[9] A.R. Molavi, A.P. Parvishi, Investigation of hydraulic failure of earth dam under the impact of near-earthquake, 5th National Conference on Applied Research in Civil Engineering, Urban Architecture and Management, Tehran, (2017).
[10] M. Rezapur Tabari, M. Hashempour, Investigation of Parameters Effective on Hydraulic Failure of Dam, Second National Conference on Hydrology, Tehran, (2017).
[11] B. Abbasi, K. Esmaeili, J. Abrishami, Simulation of the hydraulic fracture failure of dam with rapid flood entry into the reservoir, J. Water Soil, 24(1) (2010) 75-83.
[12] S.A. Khamesi, A.S. Mirghasemi, Investigation of hydraulic failure in earth dams, J. Civi. Surv. Eng., 44(2) (2010) 181-191.
[13] M. Salari, A. Akhtarpour, A. Ekrami Fard, Occurrence of hydraulic fracturing in inclined clay core of a high rockfill dam, located in narrow valley, Modares Civ. Eng. J., 17(5) (2017) 109-122.
[14] A. Asakareh, M. Ahang, Numerical analysis of arching phenomenon at core of baft zoned embankment dam, Kerman, Modares Civ. Eng. J., 17(5) (2017) 161-168.
[15] A. Ghanbari, Principles of Earth Dam Engineering, Kharazmi University Publication, (2014).