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Evaluating permeability and groutability at the Karun
4 dam Iran using Lugeon values and grout Take
Mohammad Hosseiny Sohi1, Prof.Dr. Manfred Koch1, Dr. Javad Ashjari 2
1 Department of Geohydraulics and Engineering Hydrology, Kassel University, Kassel, Germany2 School of Geology, University of Tehran, Tehran, Iran
Contents
Introduction
Study area and dam specifications
Methodology and data
Results
Conclusions
References
Introduction
Water leakage through the foundation and abutments of a dam which is built on
limestone formations, is one of the most important challenges of the big dams’
construction and operation.
The water- soluble carbonate structure of such limestone may lead to the
development of fissures and fractures that may, eventually, expand to conduits
and even caverns and caves; a process which is known as karstification
(Milanović, 2004; Ford & Williams, 2007).
In the present study, the permeability as the most important parameter
determining water seepage of the Karun 4 dam, constructed on a limestone
formation with karst potential will be presented.
Study area and dam specifications
The Karun 4 Dam is located on the Karun River in the state of Chaharmahal and
Bakhtiari, at a distance of 180 km from the State Capital of Shahrekord, in
southwest Iran.
It is the highest dam of Iran (230 m from foundation) and has been impounded
since March 2010.
Karun 4 dam technical specifications
Location and details of the Karun 4 dam in Iran
Study area and dam specifications
Grout Curtain
To seal the dam foundation and abutments, a very large grout curtain was
designed and constructed.
The construction was done through the excavation of 5 series of galleries in
both left and right abutments at different elevations.
From inside these galleries the grouting boreholes are drilled and injected, to
have an integrated virtually wall or barrier, called grout curtain against water
leakage.
Based on the obtained results from the exploratory boreholes, the grout
curtain in two lines was designed and constructed, to sew/stitch the dam
structure to the Pabdeh impermeable formation in the upstream.
Selected Exploratory- , line 1 and line 2 check holes in the
grouting galleries
3D view of Karun 4 dam body and grouting galleries
Methodology
Water pressure test (WPT) or Lugeon test
Water pressure test, packer test or simply Lugeon test has been developed by
Professor Maurice Lugeon (1933).
A Lugeon unit is defined as one liter/minute of water absorption per meter of test
length of drill hole when the water in the borehole remains at a pressure of 10
bars or 1 MPa over a period of 10 minutes (Lugeon, 1933; Houlsby, 1990; Singh
and Goel, 1999).
Methodology
Take
The (grout) Take is defined as the rate of dry cement mass that is injected to
the test section, divided to the length of section (kg/m) (Deere 1982).
Methodology
Ewert Method
Ewert (1985) proposed a
qualitative method to
interpret the relationship
between permeability and
groutability in the dam
foundations. He classified
the obtained results from
different dam sites and
tests in to following
grouping:
Methodology
Ewert Method
Group A: large amount of Lugeon value and low grout Take indicates that water
can pass through the numerous fine fissures of the rock, but the corresponding
grout is not permitted.
Group B: Approximately proportionality between water and Take justifies well
the necessity of grouting.
Group C: The small water pass versus large Take cause to the hydraulic
fracture in the rock mass and shows that either the injection pressure is not
proper or at all unnecessary.
Group D: Low water and Take signs the sealing of area and no need no
treatment.
Results
Lugeon Permeability
Frequency distribution of Lugeon values in the different classes for
exploratory, line 1 and line 2 check holes for the left and right banks.
20 21
33
18
7
34
43
20
2 1
27
55
18
0 00
10
20
30
40
50
60
0 - 3 3 - 10 10 - 30 30 - 60 > 60
Fre
qu
en
cy %
Lugeon Values of Left Bank
Exploratory holes
Line 1 check holes
Line 2 check holes
34
41
24
16
7
56
34
9
10
48
38
10
5
00
10
20
30
40
50
60
0 - 3 3 - 10 10 - 30 30 - 60 > 60
Fre
qu
en
cy %
Lugeon Values of Right Bank
Exploratory holes
Line 1 check holes
Line 2 check holes
Results
Groutability
Frequency distribution of Take in the different classes for exploratory, line 1
and line 2 check holes for the left and right banks.
42
17
7 7 69
12
59
18
11
7
3 2 1
78
6
10
13
1 1
0
10
20
30
40
50
60
70
80
90
0 - 12.5 12.5 - 25 25 - 50 50 - 100 100 - 200 200 - 400 > 400
Fre
qu
en
cy %
Take Values of Left Bank
Exploratory holes
Line 1 check holes
Line 2 check holes48
14
57 7
108
56
1311 12
42 2
81
7
2 2 2 2 2
0
10
20
30
40
50
60
70
80
90
0 - 12.5 12.5 - 25 25 - 50 50 - 100 100 - 200 200 - 400 > 400
Fre
qu
en
cy %
Take Values of Right Bank
Exploratory holes
Line 1 check holes
Line 2 check holes
Results
Correlation of Lu- permeability and Take- groutability based on Ewert’s method
Lugeon versus Take with the four Ewert’s groupings for the exploratory holes
Results
Correlation of Lu- permeability and Take- groutability based on Ewert’s method
Lugeon versus Take with the four Ewert’s groupings for the line 1 check holes
Results
Correlation of Lu- permeability and Take- groutability based on Ewert’s method
Lugeon versus Take with the four Ewert’s groupings for the line 2 check holes
Results
Correlation of Lu- permeability and Take- groutability based on Ewert’s
method
Frequency distribution of Lu-Take pairs in the different groups for exploratory,
and line 1 and line 2 check holes for the left and right banks.
Conclusions
The grout curtain of Karun 4 dam is constructed on the dam foundation and
abutments to prevent, or minimize the water leakage from the dam reservoir
after impounding.
The measurements include Lugeon- and grout- Take values of exploratory-,
line 1 and line 2 check holes of the grout curtain.
Totally, data from 64 selected boreholes are used to study the relation
between Lugeon (Lu) permeability and groutability (Take) and, based on the
values of these two variables, classified into four groups, following Ewert’s
methodology.
The results indicate that the implemented grout curtains can seal leaking, as
Take is lower than 50 kg/m in more than 90% of the boreholes – the
requirement for efficient grout Take -, although there are still areas with
medium Lugeon values, i.e. data in Evert’s class A.
Conclusions
The Lu- values indicate that the permeabilities of the right bank are generally
lower than those of the left bank. This can be explained by the geological
characteristics underneath the dam of the Asmari formation (AS1) subunits.
Nevertheless there is still some scattering of Lu-Take pairs into Evert’s A-
group, which means that water leakage exists at these locations. The technical
solution would be to allow the extra water to seep through a drainage curtain.
Related and Ongoing studies
The seepage analysis through the drainage curtain is the topic of the presented
study of the authors as Poster in the Meeting:
Monitoring of the seepage controlling system of the Karun 4 dam in Iran
Furthermore, a numerical groundwater flow model is needed, to get a more
comprehensive and quantitative picture of the water flow seepage through the
dam foundation and abutments, which is the ongoing study of the authors
An example of the
groundwater flow
model results
Code:
CFP for Modflow 2005
GUI:
Molde Muse USGS
References Azimian A, & Ajalloeian R (2013). Comparison between Lugeon with Secondary Permeability Index obtained of Water Pressure
Test in Rock Masses. Electronic Journal of Geotechnical Engineering, Volume 18.
Barton N, Bandis S, & Bakhtar K (1985). Strength, deformation and conductivity coupling of rock joints. International Journal of
Rock Mechanics and Mining Sciences & Geomechanics Abstracts, Volume 22, Issue 3, pp 121–140.
Berhane G, & Walraevens K (2013). Geological challenges in constructing the proposed Geba dam site, northern Ethiopia.
Bulletin of Engineering Geology and the Environment, Volume 72, Issue 3-4, pp 339–352.
Bonacci O, & Roje-Bonacci T (2008). Water losses from the Ričice reservoir built in the Dinaric karst. Engineering Geology,
Voume 99, Issue 3, pp 121–127.
Deere DU (1982). Cement-bentonite grouting for dams. ASCE, Geotechnical Engineering Specialty Conference on Grouting,
New Orleans, pp 279–300.
Ewert, FK (1985). Rock Grouting with Emphasis on Dam Sites. Springer Berlin Heidelberg.
Fell R, MacGregor P, Stapledon D, Bell G, & Foster M (2015). Geotechnical engineering of dams. 2nd edition, CRC Press.
Ford D, & Williams PW (2007). Karst hydrogeology and geomorphology. [Rev. ed.]. Chichester, England, A Hoboken, NJ: John
Wiley & Sons.
Foyo A, Sánchez MA, & Tomillo C (2005). A proposal for a Secondary Permeability Index obtained from water pressure tests in
dam foundations. Engineering Geology, volume 77, Issue 1-2, pp 69–82.
Gurocak Z, & Alemdag S (2012). Assessment of permeability and injection depth at the Atasu dam site (Turkey) based on
experimental and numerical analyses. Bulletin of Engineering Geology and the Environment, Volume 71, Issue 2, pp 221–229.
Haghnejad A, Ahangari K, & Noorzad A (2014). Investigation on Various Relations Between Uniaxial Compressive Strength,
Elasticity and Deformation Modulus of Asmari Formation in Iran. Arabian Journal for Science and Engineering, Volume 39, Issue
4, pp 2677–2682.
References Azimian A, & Ajalloeian R (2013). Comparison between Lugeon with Secondary Permeability Index obtained of Water Pressure
Test in Rock Masses. Electronic Journal of Geotechnical Engineering, Volume 18.
Hosseiny Sohi SM, Koch M, Ashjari J (2014). Construction Effects of the Karun 4 Dam, Iran, on the Groundwater in the Adjacent
Karstic Aquifer. ICHE 2014, Hamburg - Lehfeldt & Kopmann (eds).
Houlsby AC (1990). Construction and design of cement grouting. A guide to grouting in rock foundations. New York, Wiley (Wiley
series of practical construction guides).
Kocbay A, & Kilic R (2006). Engineering geological assessment of the Obruk dam site (Corum, Turkey). Engineering Geology,
Volume 87, Issue 3, pp 141–148.
Lugeon M (1933). Barrages et Geologie. Dunod, Paris
Mahab Ghods Consulting Engineering Co. (2002). Final engineering geological report (phase 2). Karun 4 dam project.
Mahab Ghods Consulting Engineering Co. (2010). Final excavation and injection report of the Karun 4 dam grout curtain.
Sadeghiyeh SM, Hashemi M, & Ajalloeian R (2013). Comparison of Permeability and Groutability of Ostur Dam Site Rock Mass
for Grout Curtain Design. Rock mechanics and rock engineering, volume 46, Issue 2, pp 341–357.
Turkmen S, Özgüler E, Taga H, & Karaogullarindan Talip (2002). Seepage problems in the karstic limestone foundation of the
Kalecik Dam (south Turkey). Engineering Geology, Volume 63, Issue 3, pp 247–257.
Uromeihy A, & Barzegari G (2007). Evaluation and treatment of seepage problems at Chapar-Abad Dam, Iran. Engineering
Geology, Volume 91, Issue 2, pp 219–228.
Uromeihy A, & Farrokhi R (2012). Evaluating groutability at the Kamal-Saleh Dam based on Lugeon tests. Bullten of Engineering
Geology Environmental, Volume 71, Issue 2, pp 215–219.
Yang, ChP (2004). Estimating cement take and grout efficiency on foundation improvement for Li-Yu-Tan dam. Engineering
Geology, Volume 75, Issue 6, pp 1–14.
Thanks for your attention!
S. Mohammad Hosseiny sohi
Ph.D. Candidate in Civil Engineering
Department of Geo-hydraulics and Hydrology Engineering
Faculty of Civil- and Environmental Engineering
University of Kassel
Kurt-Wolters-Straße 3
34125 Kassel,
Germany
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