Volume 13, Number 1 and B (Transaction B: Geotechnical Engineering March 2015)                   IJCE 2015, 13(1 and B): 73-80 | Back to browse issues page



DOI: 10.22068/IJCE.13.1.73

XML Print


Download citation:
BibTeX | RIS | EndNote | Medlars | ProCite | Reference Manager | RefWorks
Send citation to:

Heidarzadeh M, Mirghasemi A A, Niroomand H. Construction of relief wells under artesian flow conditions at dam toes: engineering experiences from Karkheh earth dam, Iran. IJCE. 2015; 13 (1) :73-80
URL: http://ijce.iust.ac.ir/article-1-927-en.html

Abstract:   (2887 Views)
We report engineering experiences from the critical task of relief well installation under high artesian flow conditions at the downstream toe of the Karkheh earth dam, Iran. Due to the establishment of excessive uplift pressure at the downstream toe of the Karkheh dam, installation of a series of new relief wells was considered to permanently relieve part of these pressures. The mentioned uplift pressure, as high as around 30 m above the ground level, was produced in a confined conglomerate aquifer bounded above and below by relatively impervious mudstone layers which reduced the safety factor of the dam toe to below 1.0. Investigations on the shortcomings of the old relief wells installed at the dam site showed that the main problems were: insufficient well numbers, insufficient well diameters, irregular well screens causing their blockage by time passing, and insufficient total opening area. Despite engineering difficulties and associated risk of downstream toe instability, installation of new relief wells was successfully completed under high artesian flow conditions” was successfully completed. The employed technique for the construction of the new relief wells under flowing artesian conditions was based on: 1) cement grouting and casing of the well, 2) telescopic drilling, 3) application of appropriate drilling fluid, and 4) controlling the artesian flow by adding a long vertical pipe to the top of the relief wells. Numerical modeling of seepage for the Karkheh dam foundation showed that, as a result of the installation of the new relief wells, the safety factor of the downstream toe increased to the safe value of 1.3 for the normal reservoir water level.
Full-Text [PDF 1216 kb]   (1553 Downloads)    
Type of Study: Technical Note | Subject: Geotechnique

Add your comments about this article : Your username or email:
Write the security code in the box

© 2015 All Rights Reserved | International Journal of Civil Engineering

Designed & Developed by : Yektaweb