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Stability of non-cohesive Soils with respect to Internal Erosion
Dr-Ing Marx F Ahlinhan
IMPaC Group
International Conference on Scour and Erosion Paris France 2012
Stability of non-cohesive Soils with respect to Internal Erosion
Table of Contents
State of the Art
Model Tests
Results
Results Evaluation
Summary
Stability of non-cohesive Soils with respect to Internal Erosion 3
State of the Art
L L
ΔH
Schematic sketch of piping channel occurring at the downstream end of
a dycke (left) and a river barrage (right)
Stability of non-cohesive Soils with respect to Internal Erosion 4
Criteria for the Evaluation of Internal Erosion
Geometric criteria
Kezdi (1979) Splitting up of the grain size
distribution into fine fraction and coarse
fraction
Kenney et Lau (1985-1986)
H-F-Diagram
HF ge 10 for interne stable soil
F F
H
d 4d0
100
50
Silt Sand Gravel
Perc
enta
ge fin
er
by w
eig
ht
Grain diameter
Grain size distribution H - F diagram
Evaluation limit for well-graded soils
(H F)min
F
03
02
01
0
H
0 01 02 03
H -
F
d15F
d85b
lt 4 U lt2F U lt2b
d = 0002 0006 002 006 02 06 20 60 20 63 0
100
90
80
70
60
50
40
30
20
10
Silt Sand GravelFine- Fine- Fine-Medium- Medium- Medium-Coarse- Coarse- Coarse-
Perc
ent finer
by w
eig
ht
E2Fine fraction Coarse fraction
d85b d15F
= 72 d85bd15F
Grain diameter d in mm
State of the Art
Stability of non-cohesive Soils with respect to Internal Erosion 5
State of the Art
Hydraulic Criteria
Istomina (1957)
Terzaghi et Peck (1961) Approach for vertical
upward seepage
Skempton et Brogan (1994) Suffosion in Sand-Gravel
Upward vertical seepage
ikrit = (13 to 15)ikrittheo
0
05
10
15
20
Critical gra
die
nt i
v
cri
t
Uniformity index Cu
0 10 20 30 40
Test results
Proposed design curve
0 1 2 3
Critical gra
die
nt i c
rit
(HF)min
unstable stable
Upward vertical flow (Skempton amp Brogan 1994)
Horizontal flow (Adel et al 1988)
ikritv = acutew
acutemf
acutemG
with
i =kritv acute
w
Stability of non-cohesive Soils with respect to Internal Erosion 6
Proposed approach for Splitting Up
tan =H
log4d - logd
Proposed approach for Splitting Up
β minimal H minimal
(d15Fd85b) = (d15Fd85b) at (HF)min
Stability of non-cohesive Soils with respect to Internal Erosion 7
Model Tests
Investigated Soils Grain Size Distribution
Stability of non-cohesive Soils with respect to Internal Erosion 8
Model Tests
Experiment set up for upward vertical Seepage Flow
Soil sample 30cm diameter 30cm height
Stability of non-cohesive Soils with respect to Internal Erosion 9
Model Tests
Sand boils at Mississippi river
Levee (after Glynn (2004)) Total failure due to piping
(current test for vertical
upward seepage)
Stable Zone
Effectif Stress Zero - Zone
Failure Zone
Phenomenological observation for upward vertical seepage flow
Stability of non-cohesive Soils with respect to Internal Erosion 10
Model Tests
Experimental set up for horizontal Seepage Flow
Soil sample widthheightdepth=60cm30cm10cm
Stability of non-cohesive Soils with respect to Internal Erosion 11
Test Results
E2
A1
0 4 8 12 16 20
06
08
10
04
02
0
Critical h
yd
raulic
g
radie
nt i c
rit [1
]
unstable
stable
horizontal tests
vertical tests
Transition zone for stable soils
Transition zone for unstable soils
Limit for U gt 25after Istomina (1957)
E1
E5
Instability (d d ) [1]15f 85b mod index
D=075
D=076
D=070D=058
D=050
D=040D=045
D=059
D=060
D=031
D=085
D=060D=050
D=095D=041
D=085 D=085
D=075
D=075
D=050
D=025
D=092
Test Results hydraulic aspect
Stability of non-cohesive Soils with respect to Internal Erosion 12
Test Results
01
02
03
04
05
0
H M
ass fra
ction o
f part
icle
s
betw
een d
and 4
d [1]
0 01 02 03 04 05 F Mass fraction of particles smaller than d [1]
Kenney et L
au (1986)
H = F083 071
Kezdi (1979) H = 015
(a) stable
(b) unstable
(d)
(c)
Own tests
Adel (1988)
Kenney and Lau (1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li and Fannin (2008)
Lafleur (1984)
Wan and Fell (2008)
stable unstable Author
A1 A2
E1
E2E5
Test Results geometric aspect
Stability of non-cohesive Soils with respect to Internal Erosion 13
Evaluation of the Test Results
0
16
12
4
8
Insta
bili
ty
(d
d)
[1]
inde
x
15f
85b
mod
06 04 02 0
D = 095
D = 070
D = 040lower limit
0 01 02 03 04 05
01
02
03
04
06
05
0
083 071
Kenney et Lau (1
986) H =
F
Kezdi (1979) H = 015
A1 A2
E1
E5
E1
E2
E5
015
003
upper limit
E272
Own tests
Adel (1988)
Kenney et Lau(1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li et Fannin (2008)
Lafleur (1984)
Wan et Fell (2008)
stable unstable Author
H M
ass fra
ction o
f p
art
icle
s
be
twee
n d
and
4d [1]
F Mass fraction of particles smaller than d [1]
(a) stable
(b) unstable
i = 018critv
Critical vertical gradient i [1]critv
Combined geometric and hydraulic criteria
Stability of non-cohesive Soils with respect to Internal Erosion 14
Summary
Problem
Internal erosion
Several approaches exist for the evaluation
Approaches lead to different results
Results of current Investigations
Controlling parameters have been idenfied by model tests
Uniformity coefficient Cu might not be adequate for a reliable
assessment of internal erosion
Modified (d15Fd85b) mod is promising
Diagrams have been proposed for the evaluation of the internal
erosion stability
Stability of non-cohesive Soils with respect to Internal Erosion
Thank you for your
attention
wwwimpacde
Stability of non-cohesive Soils with respect to Internal Erosion
Table of Contents
State of the Art
Model Tests
Results
Results Evaluation
Summary
Stability of non-cohesive Soils with respect to Internal Erosion 3
State of the Art
L L
ΔH
Schematic sketch of piping channel occurring at the downstream end of
a dycke (left) and a river barrage (right)
Stability of non-cohesive Soils with respect to Internal Erosion 4
Criteria for the Evaluation of Internal Erosion
Geometric criteria
Kezdi (1979) Splitting up of the grain size
distribution into fine fraction and coarse
fraction
Kenney et Lau (1985-1986)
H-F-Diagram
HF ge 10 for interne stable soil
F F
H
d 4d0
100
50
Silt Sand Gravel
Perc
enta
ge fin
er
by w
eig
ht
Grain diameter
Grain size distribution H - F diagram
Evaluation limit for well-graded soils
(H F)min
F
03
02
01
0
H
0 01 02 03
H -
F
d15F
d85b
lt 4 U lt2F U lt2b
d = 0002 0006 002 006 02 06 20 60 20 63 0
100
90
80
70
60
50
40
30
20
10
Silt Sand GravelFine- Fine- Fine-Medium- Medium- Medium-Coarse- Coarse- Coarse-
Perc
ent finer
by w
eig
ht
E2Fine fraction Coarse fraction
d85b d15F
= 72 d85bd15F
Grain diameter d in mm
State of the Art
Stability of non-cohesive Soils with respect to Internal Erosion 5
State of the Art
Hydraulic Criteria
Istomina (1957)
Terzaghi et Peck (1961) Approach for vertical
upward seepage
Skempton et Brogan (1994) Suffosion in Sand-Gravel
Upward vertical seepage
ikrit = (13 to 15)ikrittheo
0
05
10
15
20
Critical gra
die
nt i
v
cri
t
Uniformity index Cu
0 10 20 30 40
Test results
Proposed design curve
0 1 2 3
Critical gra
die
nt i c
rit
(HF)min
unstable stable
Upward vertical flow (Skempton amp Brogan 1994)
Horizontal flow (Adel et al 1988)
ikritv = acutew
acutemf
acutemG
with
i =kritv acute
w
Stability of non-cohesive Soils with respect to Internal Erosion 6
Proposed approach for Splitting Up
tan =H
log4d - logd
Proposed approach for Splitting Up
β minimal H minimal
(d15Fd85b) = (d15Fd85b) at (HF)min
Stability of non-cohesive Soils with respect to Internal Erosion 7
Model Tests
Investigated Soils Grain Size Distribution
Stability of non-cohesive Soils with respect to Internal Erosion 8
Model Tests
Experiment set up for upward vertical Seepage Flow
Soil sample 30cm diameter 30cm height
Stability of non-cohesive Soils with respect to Internal Erosion 9
Model Tests
Sand boils at Mississippi river
Levee (after Glynn (2004)) Total failure due to piping
(current test for vertical
upward seepage)
Stable Zone
Effectif Stress Zero - Zone
Failure Zone
Phenomenological observation for upward vertical seepage flow
Stability of non-cohesive Soils with respect to Internal Erosion 10
Model Tests
Experimental set up for horizontal Seepage Flow
Soil sample widthheightdepth=60cm30cm10cm
Stability of non-cohesive Soils with respect to Internal Erosion 11
Test Results
E2
A1
0 4 8 12 16 20
06
08
10
04
02
0
Critical h
yd
raulic
g
radie
nt i c
rit [1
]
unstable
stable
horizontal tests
vertical tests
Transition zone for stable soils
Transition zone for unstable soils
Limit for U gt 25after Istomina (1957)
E1
E5
Instability (d d ) [1]15f 85b mod index
D=075
D=076
D=070D=058
D=050
D=040D=045
D=059
D=060
D=031
D=085
D=060D=050
D=095D=041
D=085 D=085
D=075
D=075
D=050
D=025
D=092
Test Results hydraulic aspect
Stability of non-cohesive Soils with respect to Internal Erosion 12
Test Results
01
02
03
04
05
0
H M
ass fra
ction o
f part
icle
s
betw
een d
and 4
d [1]
0 01 02 03 04 05 F Mass fraction of particles smaller than d [1]
Kenney et L
au (1986)
H = F083 071
Kezdi (1979) H = 015
(a) stable
(b) unstable
(d)
(c)
Own tests
Adel (1988)
Kenney and Lau (1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li and Fannin (2008)
Lafleur (1984)
Wan and Fell (2008)
stable unstable Author
A1 A2
E1
E2E5
Test Results geometric aspect
Stability of non-cohesive Soils with respect to Internal Erosion 13
Evaluation of the Test Results
0
16
12
4
8
Insta
bili
ty
(d
d)
[1]
inde
x
15f
85b
mod
06 04 02 0
D = 095
D = 070
D = 040lower limit
0 01 02 03 04 05
01
02
03
04
06
05
0
083 071
Kenney et Lau (1
986) H =
F
Kezdi (1979) H = 015
A1 A2
E1
E5
E1
E2
E5
015
003
upper limit
E272
Own tests
Adel (1988)
Kenney et Lau(1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li et Fannin (2008)
Lafleur (1984)
Wan et Fell (2008)
stable unstable Author
H M
ass fra
ction o
f p
art
icle
s
be
twee
n d
and
4d [1]
F Mass fraction of particles smaller than d [1]
(a) stable
(b) unstable
i = 018critv
Critical vertical gradient i [1]critv
Combined geometric and hydraulic criteria
Stability of non-cohesive Soils with respect to Internal Erosion 14
Summary
Problem
Internal erosion
Several approaches exist for the evaluation
Approaches lead to different results
Results of current Investigations
Controlling parameters have been idenfied by model tests
Uniformity coefficient Cu might not be adequate for a reliable
assessment of internal erosion
Modified (d15Fd85b) mod is promising
Diagrams have been proposed for the evaluation of the internal
erosion stability
Stability of non-cohesive Soils with respect to Internal Erosion
Thank you for your
attention
wwwimpacde
Stability of non-cohesive Soils with respect to Internal Erosion 3
State of the Art
L L
ΔH
Schematic sketch of piping channel occurring at the downstream end of
a dycke (left) and a river barrage (right)
Stability of non-cohesive Soils with respect to Internal Erosion 4
Criteria for the Evaluation of Internal Erosion
Geometric criteria
Kezdi (1979) Splitting up of the grain size
distribution into fine fraction and coarse
fraction
Kenney et Lau (1985-1986)
H-F-Diagram
HF ge 10 for interne stable soil
F F
H
d 4d0
100
50
Silt Sand Gravel
Perc
enta
ge fin
er
by w
eig
ht
Grain diameter
Grain size distribution H - F diagram
Evaluation limit for well-graded soils
(H F)min
F
03
02
01
0
H
0 01 02 03
H -
F
d15F
d85b
lt 4 U lt2F U lt2b
d = 0002 0006 002 006 02 06 20 60 20 63 0
100
90
80
70
60
50
40
30
20
10
Silt Sand GravelFine- Fine- Fine-Medium- Medium- Medium-Coarse- Coarse- Coarse-
Perc
ent finer
by w
eig
ht
E2Fine fraction Coarse fraction
d85b d15F
= 72 d85bd15F
Grain diameter d in mm
State of the Art
Stability of non-cohesive Soils with respect to Internal Erosion 5
State of the Art
Hydraulic Criteria
Istomina (1957)
Terzaghi et Peck (1961) Approach for vertical
upward seepage
Skempton et Brogan (1994) Suffosion in Sand-Gravel
Upward vertical seepage
ikrit = (13 to 15)ikrittheo
0
05
10
15
20
Critical gra
die
nt i
v
cri
t
Uniformity index Cu
0 10 20 30 40
Test results
Proposed design curve
0 1 2 3
Critical gra
die
nt i c
rit
(HF)min
unstable stable
Upward vertical flow (Skempton amp Brogan 1994)
Horizontal flow (Adel et al 1988)
ikritv = acutew
acutemf
acutemG
with
i =kritv acute
w
Stability of non-cohesive Soils with respect to Internal Erosion 6
Proposed approach for Splitting Up
tan =H
log4d - logd
Proposed approach for Splitting Up
β minimal H minimal
(d15Fd85b) = (d15Fd85b) at (HF)min
Stability of non-cohesive Soils with respect to Internal Erosion 7
Model Tests
Investigated Soils Grain Size Distribution
Stability of non-cohesive Soils with respect to Internal Erosion 8
Model Tests
Experiment set up for upward vertical Seepage Flow
Soil sample 30cm diameter 30cm height
Stability of non-cohesive Soils with respect to Internal Erosion 9
Model Tests
Sand boils at Mississippi river
Levee (after Glynn (2004)) Total failure due to piping
(current test for vertical
upward seepage)
Stable Zone
Effectif Stress Zero - Zone
Failure Zone
Phenomenological observation for upward vertical seepage flow
Stability of non-cohesive Soils with respect to Internal Erosion 10
Model Tests
Experimental set up for horizontal Seepage Flow
Soil sample widthheightdepth=60cm30cm10cm
Stability of non-cohesive Soils with respect to Internal Erosion 11
Test Results
E2
A1
0 4 8 12 16 20
06
08
10
04
02
0
Critical h
yd
raulic
g
radie
nt i c
rit [1
]
unstable
stable
horizontal tests
vertical tests
Transition zone for stable soils
Transition zone for unstable soils
Limit for U gt 25after Istomina (1957)
E1
E5
Instability (d d ) [1]15f 85b mod index
D=075
D=076
D=070D=058
D=050
D=040D=045
D=059
D=060
D=031
D=085
D=060D=050
D=095D=041
D=085 D=085
D=075
D=075
D=050
D=025
D=092
Test Results hydraulic aspect
Stability of non-cohesive Soils with respect to Internal Erosion 12
Test Results
01
02
03
04
05
0
H M
ass fra
ction o
f part
icle
s
betw
een d
and 4
d [1]
0 01 02 03 04 05 F Mass fraction of particles smaller than d [1]
Kenney et L
au (1986)
H = F083 071
Kezdi (1979) H = 015
(a) stable
(b) unstable
(d)
(c)
Own tests
Adel (1988)
Kenney and Lau (1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li and Fannin (2008)
Lafleur (1984)
Wan and Fell (2008)
stable unstable Author
A1 A2
E1
E2E5
Test Results geometric aspect
Stability of non-cohesive Soils with respect to Internal Erosion 13
Evaluation of the Test Results
0
16
12
4
8
Insta
bili
ty
(d
d)
[1]
inde
x
15f
85b
mod
06 04 02 0
D = 095
D = 070
D = 040lower limit
0 01 02 03 04 05
01
02
03
04
06
05
0
083 071
Kenney et Lau (1
986) H =
F
Kezdi (1979) H = 015
A1 A2
E1
E5
E1
E2
E5
015
003
upper limit
E272
Own tests
Adel (1988)
Kenney et Lau(1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li et Fannin (2008)
Lafleur (1984)
Wan et Fell (2008)
stable unstable Author
H M
ass fra
ction o
f p
art
icle
s
be
twee
n d
and
4d [1]
F Mass fraction of particles smaller than d [1]
(a) stable
(b) unstable
i = 018critv
Critical vertical gradient i [1]critv
Combined geometric and hydraulic criteria
Stability of non-cohesive Soils with respect to Internal Erosion 14
Summary
Problem
Internal erosion
Several approaches exist for the evaluation
Approaches lead to different results
Results of current Investigations
Controlling parameters have been idenfied by model tests
Uniformity coefficient Cu might not be adequate for a reliable
assessment of internal erosion
Modified (d15Fd85b) mod is promising
Diagrams have been proposed for the evaluation of the internal
erosion stability
Stability of non-cohesive Soils with respect to Internal Erosion
Thank you for your
attention
wwwimpacde
Stability of non-cohesive Soils with respect to Internal Erosion 4
Criteria for the Evaluation of Internal Erosion
Geometric criteria
Kezdi (1979) Splitting up of the grain size
distribution into fine fraction and coarse
fraction
Kenney et Lau (1985-1986)
H-F-Diagram
HF ge 10 for interne stable soil
F F
H
d 4d0
100
50
Silt Sand Gravel
Perc
enta
ge fin
er
by w
eig
ht
Grain diameter
Grain size distribution H - F diagram
Evaluation limit for well-graded soils
(H F)min
F
03
02
01
0
H
0 01 02 03
H -
F
d15F
d85b
lt 4 U lt2F U lt2b
d = 0002 0006 002 006 02 06 20 60 20 63 0
100
90
80
70
60
50
40
30
20
10
Silt Sand GravelFine- Fine- Fine-Medium- Medium- Medium-Coarse- Coarse- Coarse-
Perc
ent finer
by w
eig
ht
E2Fine fraction Coarse fraction
d85b d15F
= 72 d85bd15F
Grain diameter d in mm
State of the Art
Stability of non-cohesive Soils with respect to Internal Erosion 5
State of the Art
Hydraulic Criteria
Istomina (1957)
Terzaghi et Peck (1961) Approach for vertical
upward seepage
Skempton et Brogan (1994) Suffosion in Sand-Gravel
Upward vertical seepage
ikrit = (13 to 15)ikrittheo
0
05
10
15
20
Critical gra
die
nt i
v
cri
t
Uniformity index Cu
0 10 20 30 40
Test results
Proposed design curve
0 1 2 3
Critical gra
die
nt i c
rit
(HF)min
unstable stable
Upward vertical flow (Skempton amp Brogan 1994)
Horizontal flow (Adel et al 1988)
ikritv = acutew
acutemf
acutemG
with
i =kritv acute
w
Stability of non-cohesive Soils with respect to Internal Erosion 6
Proposed approach for Splitting Up
tan =H
log4d - logd
Proposed approach for Splitting Up
β minimal H minimal
(d15Fd85b) = (d15Fd85b) at (HF)min
Stability of non-cohesive Soils with respect to Internal Erosion 7
Model Tests
Investigated Soils Grain Size Distribution
Stability of non-cohesive Soils with respect to Internal Erosion 8
Model Tests
Experiment set up for upward vertical Seepage Flow
Soil sample 30cm diameter 30cm height
Stability of non-cohesive Soils with respect to Internal Erosion 9
Model Tests
Sand boils at Mississippi river
Levee (after Glynn (2004)) Total failure due to piping
(current test for vertical
upward seepage)
Stable Zone
Effectif Stress Zero - Zone
Failure Zone
Phenomenological observation for upward vertical seepage flow
Stability of non-cohesive Soils with respect to Internal Erosion 10
Model Tests
Experimental set up for horizontal Seepage Flow
Soil sample widthheightdepth=60cm30cm10cm
Stability of non-cohesive Soils with respect to Internal Erosion 11
Test Results
E2
A1
0 4 8 12 16 20
06
08
10
04
02
0
Critical h
yd
raulic
g
radie
nt i c
rit [1
]
unstable
stable
horizontal tests
vertical tests
Transition zone for stable soils
Transition zone for unstable soils
Limit for U gt 25after Istomina (1957)
E1
E5
Instability (d d ) [1]15f 85b mod index
D=075
D=076
D=070D=058
D=050
D=040D=045
D=059
D=060
D=031
D=085
D=060D=050
D=095D=041
D=085 D=085
D=075
D=075
D=050
D=025
D=092
Test Results hydraulic aspect
Stability of non-cohesive Soils with respect to Internal Erosion 12
Test Results
01
02
03
04
05
0
H M
ass fra
ction o
f part
icle
s
betw
een d
and 4
d [1]
0 01 02 03 04 05 F Mass fraction of particles smaller than d [1]
Kenney et L
au (1986)
H = F083 071
Kezdi (1979) H = 015
(a) stable
(b) unstable
(d)
(c)
Own tests
Adel (1988)
Kenney and Lau (1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li and Fannin (2008)
Lafleur (1984)
Wan and Fell (2008)
stable unstable Author
A1 A2
E1
E2E5
Test Results geometric aspect
Stability of non-cohesive Soils with respect to Internal Erosion 13
Evaluation of the Test Results
0
16
12
4
8
Insta
bili
ty
(d
d)
[1]
inde
x
15f
85b
mod
06 04 02 0
D = 095
D = 070
D = 040lower limit
0 01 02 03 04 05
01
02
03
04
06
05
0
083 071
Kenney et Lau (1
986) H =
F
Kezdi (1979) H = 015
A1 A2
E1
E5
E1
E2
E5
015
003
upper limit
E272
Own tests
Adel (1988)
Kenney et Lau(1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li et Fannin (2008)
Lafleur (1984)
Wan et Fell (2008)
stable unstable Author
H M
ass fra
ction o
f p
art
icle
s
be
twee
n d
and
4d [1]
F Mass fraction of particles smaller than d [1]
(a) stable
(b) unstable
i = 018critv
Critical vertical gradient i [1]critv
Combined geometric and hydraulic criteria
Stability of non-cohesive Soils with respect to Internal Erosion 14
Summary
Problem
Internal erosion
Several approaches exist for the evaluation
Approaches lead to different results
Results of current Investigations
Controlling parameters have been idenfied by model tests
Uniformity coefficient Cu might not be adequate for a reliable
assessment of internal erosion
Modified (d15Fd85b) mod is promising
Diagrams have been proposed for the evaluation of the internal
erosion stability
Stability of non-cohesive Soils with respect to Internal Erosion
Thank you for your
attention
wwwimpacde
Stability of non-cohesive Soils with respect to Internal Erosion 5
State of the Art
Hydraulic Criteria
Istomina (1957)
Terzaghi et Peck (1961) Approach for vertical
upward seepage
Skempton et Brogan (1994) Suffosion in Sand-Gravel
Upward vertical seepage
ikrit = (13 to 15)ikrittheo
0
05
10
15
20
Critical gra
die
nt i
v
cri
t
Uniformity index Cu
0 10 20 30 40
Test results
Proposed design curve
0 1 2 3
Critical gra
die
nt i c
rit
(HF)min
unstable stable
Upward vertical flow (Skempton amp Brogan 1994)
Horizontal flow (Adel et al 1988)
ikritv = acutew
acutemf
acutemG
with
i =kritv acute
w
Stability of non-cohesive Soils with respect to Internal Erosion 6
Proposed approach for Splitting Up
tan =H
log4d - logd
Proposed approach for Splitting Up
β minimal H minimal
(d15Fd85b) = (d15Fd85b) at (HF)min
Stability of non-cohesive Soils with respect to Internal Erosion 7
Model Tests
Investigated Soils Grain Size Distribution
Stability of non-cohesive Soils with respect to Internal Erosion 8
Model Tests
Experiment set up for upward vertical Seepage Flow
Soil sample 30cm diameter 30cm height
Stability of non-cohesive Soils with respect to Internal Erosion 9
Model Tests
Sand boils at Mississippi river
Levee (after Glynn (2004)) Total failure due to piping
(current test for vertical
upward seepage)
Stable Zone
Effectif Stress Zero - Zone
Failure Zone
Phenomenological observation for upward vertical seepage flow
Stability of non-cohesive Soils with respect to Internal Erosion 10
Model Tests
Experimental set up for horizontal Seepage Flow
Soil sample widthheightdepth=60cm30cm10cm
Stability of non-cohesive Soils with respect to Internal Erosion 11
Test Results
E2
A1
0 4 8 12 16 20
06
08
10
04
02
0
Critical h
yd
raulic
g
radie
nt i c
rit [1
]
unstable
stable
horizontal tests
vertical tests
Transition zone for stable soils
Transition zone for unstable soils
Limit for U gt 25after Istomina (1957)
E1
E5
Instability (d d ) [1]15f 85b mod index
D=075
D=076
D=070D=058
D=050
D=040D=045
D=059
D=060
D=031
D=085
D=060D=050
D=095D=041
D=085 D=085
D=075
D=075
D=050
D=025
D=092
Test Results hydraulic aspect
Stability of non-cohesive Soils with respect to Internal Erosion 12
Test Results
01
02
03
04
05
0
H M
ass fra
ction o
f part
icle
s
betw
een d
and 4
d [1]
0 01 02 03 04 05 F Mass fraction of particles smaller than d [1]
Kenney et L
au (1986)
H = F083 071
Kezdi (1979) H = 015
(a) stable
(b) unstable
(d)
(c)
Own tests
Adel (1988)
Kenney and Lau (1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li and Fannin (2008)
Lafleur (1984)
Wan and Fell (2008)
stable unstable Author
A1 A2
E1
E2E5
Test Results geometric aspect
Stability of non-cohesive Soils with respect to Internal Erosion 13
Evaluation of the Test Results
0
16
12
4
8
Insta
bili
ty
(d
d)
[1]
inde
x
15f
85b
mod
06 04 02 0
D = 095
D = 070
D = 040lower limit
0 01 02 03 04 05
01
02
03
04
06
05
0
083 071
Kenney et Lau (1
986) H =
F
Kezdi (1979) H = 015
A1 A2
E1
E5
E1
E2
E5
015
003
upper limit
E272
Own tests
Adel (1988)
Kenney et Lau(1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li et Fannin (2008)
Lafleur (1984)
Wan et Fell (2008)
stable unstable Author
H M
ass fra
ction o
f p
art
icle
s
be
twee
n d
and
4d [1]
F Mass fraction of particles smaller than d [1]
(a) stable
(b) unstable
i = 018critv
Critical vertical gradient i [1]critv
Combined geometric and hydraulic criteria
Stability of non-cohesive Soils with respect to Internal Erosion 14
Summary
Problem
Internal erosion
Several approaches exist for the evaluation
Approaches lead to different results
Results of current Investigations
Controlling parameters have been idenfied by model tests
Uniformity coefficient Cu might not be adequate for a reliable
assessment of internal erosion
Modified (d15Fd85b) mod is promising
Diagrams have been proposed for the evaluation of the internal
erosion stability
Stability of non-cohesive Soils with respect to Internal Erosion
Thank you for your
attention
wwwimpacde
Stability of non-cohesive Soils with respect to Internal Erosion 6
Proposed approach for Splitting Up
tan =H
log4d - logd
Proposed approach for Splitting Up
β minimal H minimal
(d15Fd85b) = (d15Fd85b) at (HF)min
Stability of non-cohesive Soils with respect to Internal Erosion 7
Model Tests
Investigated Soils Grain Size Distribution
Stability of non-cohesive Soils with respect to Internal Erosion 8
Model Tests
Experiment set up for upward vertical Seepage Flow
Soil sample 30cm diameter 30cm height
Stability of non-cohesive Soils with respect to Internal Erosion 9
Model Tests
Sand boils at Mississippi river
Levee (after Glynn (2004)) Total failure due to piping
(current test for vertical
upward seepage)
Stable Zone
Effectif Stress Zero - Zone
Failure Zone
Phenomenological observation for upward vertical seepage flow
Stability of non-cohesive Soils with respect to Internal Erosion 10
Model Tests
Experimental set up for horizontal Seepage Flow
Soil sample widthheightdepth=60cm30cm10cm
Stability of non-cohesive Soils with respect to Internal Erosion 11
Test Results
E2
A1
0 4 8 12 16 20
06
08
10
04
02
0
Critical h
yd
raulic
g
radie
nt i c
rit [1
]
unstable
stable
horizontal tests
vertical tests
Transition zone for stable soils
Transition zone for unstable soils
Limit for U gt 25after Istomina (1957)
E1
E5
Instability (d d ) [1]15f 85b mod index
D=075
D=076
D=070D=058
D=050
D=040D=045
D=059
D=060
D=031
D=085
D=060D=050
D=095D=041
D=085 D=085
D=075
D=075
D=050
D=025
D=092
Test Results hydraulic aspect
Stability of non-cohesive Soils with respect to Internal Erosion 12
Test Results
01
02
03
04
05
0
H M
ass fra
ction o
f part
icle
s
betw
een d
and 4
d [1]
0 01 02 03 04 05 F Mass fraction of particles smaller than d [1]
Kenney et L
au (1986)
H = F083 071
Kezdi (1979) H = 015
(a) stable
(b) unstable
(d)
(c)
Own tests
Adel (1988)
Kenney and Lau (1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li and Fannin (2008)
Lafleur (1984)
Wan and Fell (2008)
stable unstable Author
A1 A2
E1
E2E5
Test Results geometric aspect
Stability of non-cohesive Soils with respect to Internal Erosion 13
Evaluation of the Test Results
0
16
12
4
8
Insta
bili
ty
(d
d)
[1]
inde
x
15f
85b
mod
06 04 02 0
D = 095
D = 070
D = 040lower limit
0 01 02 03 04 05
01
02
03
04
06
05
0
083 071
Kenney et Lau (1
986) H =
F
Kezdi (1979) H = 015
A1 A2
E1
E5
E1
E2
E5
015
003
upper limit
E272
Own tests
Adel (1988)
Kenney et Lau(1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li et Fannin (2008)
Lafleur (1984)
Wan et Fell (2008)
stable unstable Author
H M
ass fra
ction o
f p
art
icle
s
be
twee
n d
and
4d [1]
F Mass fraction of particles smaller than d [1]
(a) stable
(b) unstable
i = 018critv
Critical vertical gradient i [1]critv
Combined geometric and hydraulic criteria
Stability of non-cohesive Soils with respect to Internal Erosion 14
Summary
Problem
Internal erosion
Several approaches exist for the evaluation
Approaches lead to different results
Results of current Investigations
Controlling parameters have been idenfied by model tests
Uniformity coefficient Cu might not be adequate for a reliable
assessment of internal erosion
Modified (d15Fd85b) mod is promising
Diagrams have been proposed for the evaluation of the internal
erosion stability
Stability of non-cohesive Soils with respect to Internal Erosion
Thank you for your
attention
wwwimpacde
Stability of non-cohesive Soils with respect to Internal Erosion 7
Model Tests
Investigated Soils Grain Size Distribution
Stability of non-cohesive Soils with respect to Internal Erosion 8
Model Tests
Experiment set up for upward vertical Seepage Flow
Soil sample 30cm diameter 30cm height
Stability of non-cohesive Soils with respect to Internal Erosion 9
Model Tests
Sand boils at Mississippi river
Levee (after Glynn (2004)) Total failure due to piping
(current test for vertical
upward seepage)
Stable Zone
Effectif Stress Zero - Zone
Failure Zone
Phenomenological observation for upward vertical seepage flow
Stability of non-cohesive Soils with respect to Internal Erosion 10
Model Tests
Experimental set up for horizontal Seepage Flow
Soil sample widthheightdepth=60cm30cm10cm
Stability of non-cohesive Soils with respect to Internal Erosion 11
Test Results
E2
A1
0 4 8 12 16 20
06
08
10
04
02
0
Critical h
yd
raulic
g
radie
nt i c
rit [1
]
unstable
stable
horizontal tests
vertical tests
Transition zone for stable soils
Transition zone for unstable soils
Limit for U gt 25after Istomina (1957)
E1
E5
Instability (d d ) [1]15f 85b mod index
D=075
D=076
D=070D=058
D=050
D=040D=045
D=059
D=060
D=031
D=085
D=060D=050
D=095D=041
D=085 D=085
D=075
D=075
D=050
D=025
D=092
Test Results hydraulic aspect
Stability of non-cohesive Soils with respect to Internal Erosion 12
Test Results
01
02
03
04
05
0
H M
ass fra
ction o
f part
icle
s
betw
een d
and 4
d [1]
0 01 02 03 04 05 F Mass fraction of particles smaller than d [1]
Kenney et L
au (1986)
H = F083 071
Kezdi (1979) H = 015
(a) stable
(b) unstable
(d)
(c)
Own tests
Adel (1988)
Kenney and Lau (1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li and Fannin (2008)
Lafleur (1984)
Wan and Fell (2008)
stable unstable Author
A1 A2
E1
E2E5
Test Results geometric aspect
Stability of non-cohesive Soils with respect to Internal Erosion 13
Evaluation of the Test Results
0
16
12
4
8
Insta
bili
ty
(d
d)
[1]
inde
x
15f
85b
mod
06 04 02 0
D = 095
D = 070
D = 040lower limit
0 01 02 03 04 05
01
02
03
04
06
05
0
083 071
Kenney et Lau (1
986) H =
F
Kezdi (1979) H = 015
A1 A2
E1
E5
E1
E2
E5
015
003
upper limit
E272
Own tests
Adel (1988)
Kenney et Lau(1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li et Fannin (2008)
Lafleur (1984)
Wan et Fell (2008)
stable unstable Author
H M
ass fra
ction o
f p
art
icle
s
be
twee
n d
and
4d [1]
F Mass fraction of particles smaller than d [1]
(a) stable
(b) unstable
i = 018critv
Critical vertical gradient i [1]critv
Combined geometric and hydraulic criteria
Stability of non-cohesive Soils with respect to Internal Erosion 14
Summary
Problem
Internal erosion
Several approaches exist for the evaluation
Approaches lead to different results
Results of current Investigations
Controlling parameters have been idenfied by model tests
Uniformity coefficient Cu might not be adequate for a reliable
assessment of internal erosion
Modified (d15Fd85b) mod is promising
Diagrams have been proposed for the evaluation of the internal
erosion stability
Stability of non-cohesive Soils with respect to Internal Erosion
Thank you for your
attention
wwwimpacde
Stability of non-cohesive Soils with respect to Internal Erosion 8
Model Tests
Experiment set up for upward vertical Seepage Flow
Soil sample 30cm diameter 30cm height
Stability of non-cohesive Soils with respect to Internal Erosion 9
Model Tests
Sand boils at Mississippi river
Levee (after Glynn (2004)) Total failure due to piping
(current test for vertical
upward seepage)
Stable Zone
Effectif Stress Zero - Zone
Failure Zone
Phenomenological observation for upward vertical seepage flow
Stability of non-cohesive Soils with respect to Internal Erosion 10
Model Tests
Experimental set up for horizontal Seepage Flow
Soil sample widthheightdepth=60cm30cm10cm
Stability of non-cohesive Soils with respect to Internal Erosion 11
Test Results
E2
A1
0 4 8 12 16 20
06
08
10
04
02
0
Critical h
yd
raulic
g
radie
nt i c
rit [1
]
unstable
stable
horizontal tests
vertical tests
Transition zone for stable soils
Transition zone for unstable soils
Limit for U gt 25after Istomina (1957)
E1
E5
Instability (d d ) [1]15f 85b mod index
D=075
D=076
D=070D=058
D=050
D=040D=045
D=059
D=060
D=031
D=085
D=060D=050
D=095D=041
D=085 D=085
D=075
D=075
D=050
D=025
D=092
Test Results hydraulic aspect
Stability of non-cohesive Soils with respect to Internal Erosion 12
Test Results
01
02
03
04
05
0
H M
ass fra
ction o
f part
icle
s
betw
een d
and 4
d [1]
0 01 02 03 04 05 F Mass fraction of particles smaller than d [1]
Kenney et L
au (1986)
H = F083 071
Kezdi (1979) H = 015
(a) stable
(b) unstable
(d)
(c)
Own tests
Adel (1988)
Kenney and Lau (1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li and Fannin (2008)
Lafleur (1984)
Wan and Fell (2008)
stable unstable Author
A1 A2
E1
E2E5
Test Results geometric aspect
Stability of non-cohesive Soils with respect to Internal Erosion 13
Evaluation of the Test Results
0
16
12
4
8
Insta
bili
ty
(d
d)
[1]
inde
x
15f
85b
mod
06 04 02 0
D = 095
D = 070
D = 040lower limit
0 01 02 03 04 05
01
02
03
04
06
05
0
083 071
Kenney et Lau (1
986) H =
F
Kezdi (1979) H = 015
A1 A2
E1
E5
E1
E2
E5
015
003
upper limit
E272
Own tests
Adel (1988)
Kenney et Lau(1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li et Fannin (2008)
Lafleur (1984)
Wan et Fell (2008)
stable unstable Author
H M
ass fra
ction o
f p
art
icle
s
be
twee
n d
and
4d [1]
F Mass fraction of particles smaller than d [1]
(a) stable
(b) unstable
i = 018critv
Critical vertical gradient i [1]critv
Combined geometric and hydraulic criteria
Stability of non-cohesive Soils with respect to Internal Erosion 14
Summary
Problem
Internal erosion
Several approaches exist for the evaluation
Approaches lead to different results
Results of current Investigations
Controlling parameters have been idenfied by model tests
Uniformity coefficient Cu might not be adequate for a reliable
assessment of internal erosion
Modified (d15Fd85b) mod is promising
Diagrams have been proposed for the evaluation of the internal
erosion stability
Stability of non-cohesive Soils with respect to Internal Erosion
Thank you for your
attention
wwwimpacde
Stability of non-cohesive Soils with respect to Internal Erosion 9
Model Tests
Sand boils at Mississippi river
Levee (after Glynn (2004)) Total failure due to piping
(current test for vertical
upward seepage)
Stable Zone
Effectif Stress Zero - Zone
Failure Zone
Phenomenological observation for upward vertical seepage flow
Stability of non-cohesive Soils with respect to Internal Erosion 10
Model Tests
Experimental set up for horizontal Seepage Flow
Soil sample widthheightdepth=60cm30cm10cm
Stability of non-cohesive Soils with respect to Internal Erosion 11
Test Results
E2
A1
0 4 8 12 16 20
06
08
10
04
02
0
Critical h
yd
raulic
g
radie
nt i c
rit [1
]
unstable
stable
horizontal tests
vertical tests
Transition zone for stable soils
Transition zone for unstable soils
Limit for U gt 25after Istomina (1957)
E1
E5
Instability (d d ) [1]15f 85b mod index
D=075
D=076
D=070D=058
D=050
D=040D=045
D=059
D=060
D=031
D=085
D=060D=050
D=095D=041
D=085 D=085
D=075
D=075
D=050
D=025
D=092
Test Results hydraulic aspect
Stability of non-cohesive Soils with respect to Internal Erosion 12
Test Results
01
02
03
04
05
0
H M
ass fra
ction o
f part
icle
s
betw
een d
and 4
d [1]
0 01 02 03 04 05 F Mass fraction of particles smaller than d [1]
Kenney et L
au (1986)
H = F083 071
Kezdi (1979) H = 015
(a) stable
(b) unstable
(d)
(c)
Own tests
Adel (1988)
Kenney and Lau (1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li and Fannin (2008)
Lafleur (1984)
Wan and Fell (2008)
stable unstable Author
A1 A2
E1
E2E5
Test Results geometric aspect
Stability of non-cohesive Soils with respect to Internal Erosion 13
Evaluation of the Test Results
0
16
12
4
8
Insta
bili
ty
(d
d)
[1]
inde
x
15f
85b
mod
06 04 02 0
D = 095
D = 070
D = 040lower limit
0 01 02 03 04 05
01
02
03
04
06
05
0
083 071
Kenney et Lau (1
986) H =
F
Kezdi (1979) H = 015
A1 A2
E1
E5
E1
E2
E5
015
003
upper limit
E272
Own tests
Adel (1988)
Kenney et Lau(1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li et Fannin (2008)
Lafleur (1984)
Wan et Fell (2008)
stable unstable Author
H M
ass fra
ction o
f p
art
icle
s
be
twee
n d
and
4d [1]
F Mass fraction of particles smaller than d [1]
(a) stable
(b) unstable
i = 018critv
Critical vertical gradient i [1]critv
Combined geometric and hydraulic criteria
Stability of non-cohesive Soils with respect to Internal Erosion 14
Summary
Problem
Internal erosion
Several approaches exist for the evaluation
Approaches lead to different results
Results of current Investigations
Controlling parameters have been idenfied by model tests
Uniformity coefficient Cu might not be adequate for a reliable
assessment of internal erosion
Modified (d15Fd85b) mod is promising
Diagrams have been proposed for the evaluation of the internal
erosion stability
Stability of non-cohesive Soils with respect to Internal Erosion
Thank you for your
attention
wwwimpacde
Stability of non-cohesive Soils with respect to Internal Erosion 10
Model Tests
Experimental set up for horizontal Seepage Flow
Soil sample widthheightdepth=60cm30cm10cm
Stability of non-cohesive Soils with respect to Internal Erosion 11
Test Results
E2
A1
0 4 8 12 16 20
06
08
10
04
02
0
Critical h
yd
raulic
g
radie
nt i c
rit [1
]
unstable
stable
horizontal tests
vertical tests
Transition zone for stable soils
Transition zone for unstable soils
Limit for U gt 25after Istomina (1957)
E1
E5
Instability (d d ) [1]15f 85b mod index
D=075
D=076
D=070D=058
D=050
D=040D=045
D=059
D=060
D=031
D=085
D=060D=050
D=095D=041
D=085 D=085
D=075
D=075
D=050
D=025
D=092
Test Results hydraulic aspect
Stability of non-cohesive Soils with respect to Internal Erosion 12
Test Results
01
02
03
04
05
0
H M
ass fra
ction o
f part
icle
s
betw
een d
and 4
d [1]
0 01 02 03 04 05 F Mass fraction of particles smaller than d [1]
Kenney et L
au (1986)
H = F083 071
Kezdi (1979) H = 015
(a) stable
(b) unstable
(d)
(c)
Own tests
Adel (1988)
Kenney and Lau (1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li and Fannin (2008)
Lafleur (1984)
Wan and Fell (2008)
stable unstable Author
A1 A2
E1
E2E5
Test Results geometric aspect
Stability of non-cohesive Soils with respect to Internal Erosion 13
Evaluation of the Test Results
0
16
12
4
8
Insta
bili
ty
(d
d)
[1]
inde
x
15f
85b
mod
06 04 02 0
D = 095
D = 070
D = 040lower limit
0 01 02 03 04 05
01
02
03
04
06
05
0
083 071
Kenney et Lau (1
986) H =
F
Kezdi (1979) H = 015
A1 A2
E1
E5
E1
E2
E5
015
003
upper limit
E272
Own tests
Adel (1988)
Kenney et Lau(1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li et Fannin (2008)
Lafleur (1984)
Wan et Fell (2008)
stable unstable Author
H M
ass fra
ction o
f p
art
icle
s
be
twee
n d
and
4d [1]
F Mass fraction of particles smaller than d [1]
(a) stable
(b) unstable
i = 018critv
Critical vertical gradient i [1]critv
Combined geometric and hydraulic criteria
Stability of non-cohesive Soils with respect to Internal Erosion 14
Summary
Problem
Internal erosion
Several approaches exist for the evaluation
Approaches lead to different results
Results of current Investigations
Controlling parameters have been idenfied by model tests
Uniformity coefficient Cu might not be adequate for a reliable
assessment of internal erosion
Modified (d15Fd85b) mod is promising
Diagrams have been proposed for the evaluation of the internal
erosion stability
Stability of non-cohesive Soils with respect to Internal Erosion
Thank you for your
attention
wwwimpacde
Stability of non-cohesive Soils with respect to Internal Erosion 11
Test Results
E2
A1
0 4 8 12 16 20
06
08
10
04
02
0
Critical h
yd
raulic
g
radie
nt i c
rit [1
]
unstable
stable
horizontal tests
vertical tests
Transition zone for stable soils
Transition zone for unstable soils
Limit for U gt 25after Istomina (1957)
E1
E5
Instability (d d ) [1]15f 85b mod index
D=075
D=076
D=070D=058
D=050
D=040D=045
D=059
D=060
D=031
D=085
D=060D=050
D=095D=041
D=085 D=085
D=075
D=075
D=050
D=025
D=092
Test Results hydraulic aspect
Stability of non-cohesive Soils with respect to Internal Erosion 12
Test Results
01
02
03
04
05
0
H M
ass fra
ction o
f part
icle
s
betw
een d
and 4
d [1]
0 01 02 03 04 05 F Mass fraction of particles smaller than d [1]
Kenney et L
au (1986)
H = F083 071
Kezdi (1979) H = 015
(a) stable
(b) unstable
(d)
(c)
Own tests
Adel (1988)
Kenney and Lau (1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li and Fannin (2008)
Lafleur (1984)
Wan and Fell (2008)
stable unstable Author
A1 A2
E1
E2E5
Test Results geometric aspect
Stability of non-cohesive Soils with respect to Internal Erosion 13
Evaluation of the Test Results
0
16
12
4
8
Insta
bili
ty
(d
d)
[1]
inde
x
15f
85b
mod
06 04 02 0
D = 095
D = 070
D = 040lower limit
0 01 02 03 04 05
01
02
03
04
06
05
0
083 071
Kenney et Lau (1
986) H =
F
Kezdi (1979) H = 015
A1 A2
E1
E5
E1
E2
E5
015
003
upper limit
E272
Own tests
Adel (1988)
Kenney et Lau(1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li et Fannin (2008)
Lafleur (1984)
Wan et Fell (2008)
stable unstable Author
H M
ass fra
ction o
f p
art
icle
s
be
twee
n d
and
4d [1]
F Mass fraction of particles smaller than d [1]
(a) stable
(b) unstable
i = 018critv
Critical vertical gradient i [1]critv
Combined geometric and hydraulic criteria
Stability of non-cohesive Soils with respect to Internal Erosion 14
Summary
Problem
Internal erosion
Several approaches exist for the evaluation
Approaches lead to different results
Results of current Investigations
Controlling parameters have been idenfied by model tests
Uniformity coefficient Cu might not be adequate for a reliable
assessment of internal erosion
Modified (d15Fd85b) mod is promising
Diagrams have been proposed for the evaluation of the internal
erosion stability
Stability of non-cohesive Soils with respect to Internal Erosion
Thank you for your
attention
wwwimpacde
Stability of non-cohesive Soils with respect to Internal Erosion 12
Test Results
01
02
03
04
05
0
H M
ass fra
ction o
f part
icle
s
betw
een d
and 4
d [1]
0 01 02 03 04 05 F Mass fraction of particles smaller than d [1]
Kenney et L
au (1986)
H = F083 071
Kezdi (1979) H = 015
(a) stable
(b) unstable
(d)
(c)
Own tests
Adel (1988)
Kenney and Lau (1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li and Fannin (2008)
Lafleur (1984)
Wan and Fell (2008)
stable unstable Author
A1 A2
E1
E2E5
Test Results geometric aspect
Stability of non-cohesive Soils with respect to Internal Erosion 13
Evaluation of the Test Results
0
16
12
4
8
Insta
bili
ty
(d
d)
[1]
inde
x
15f
85b
mod
06 04 02 0
D = 095
D = 070
D = 040lower limit
0 01 02 03 04 05
01
02
03
04
06
05
0
083 071
Kenney et Lau (1
986) H =
F
Kezdi (1979) H = 015
A1 A2
E1
E5
E1
E2
E5
015
003
upper limit
E272
Own tests
Adel (1988)
Kenney et Lau(1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li et Fannin (2008)
Lafleur (1984)
Wan et Fell (2008)
stable unstable Author
H M
ass fra
ction o
f p
art
icle
s
be
twee
n d
and
4d [1]
F Mass fraction of particles smaller than d [1]
(a) stable
(b) unstable
i = 018critv
Critical vertical gradient i [1]critv
Combined geometric and hydraulic criteria
Stability of non-cohesive Soils with respect to Internal Erosion 14
Summary
Problem
Internal erosion
Several approaches exist for the evaluation
Approaches lead to different results
Results of current Investigations
Controlling parameters have been idenfied by model tests
Uniformity coefficient Cu might not be adequate for a reliable
assessment of internal erosion
Modified (d15Fd85b) mod is promising
Diagrams have been proposed for the evaluation of the internal
erosion stability
Stability of non-cohesive Soils with respect to Internal Erosion
Thank you for your
attention
wwwimpacde
Stability of non-cohesive Soils with respect to Internal Erosion 13
Evaluation of the Test Results
0
16
12
4
8
Insta
bili
ty
(d
d)
[1]
inde
x
15f
85b
mod
06 04 02 0
D = 095
D = 070
D = 040lower limit
0 01 02 03 04 05
01
02
03
04
06
05
0
083 071
Kenney et Lau (1
986) H =
F
Kezdi (1979) H = 015
A1 A2
E1
E5
E1
E2
E5
015
003
upper limit
E272
Own tests
Adel (1988)
Kenney et Lau(1985)
Burenkova (1993)
Honjo et al (1996)
Skempton (1994)
Moffat et al (2006)
Li et Fannin (2008)
Lafleur (1984)
Wan et Fell (2008)
stable unstable Author
H M
ass fra
ction o
f p
art
icle
s
be
twee
n d
and
4d [1]
F Mass fraction of particles smaller than d [1]
(a) stable
(b) unstable
i = 018critv
Critical vertical gradient i [1]critv
Combined geometric and hydraulic criteria
Stability of non-cohesive Soils with respect to Internal Erosion 14
Summary
Problem
Internal erosion
Several approaches exist for the evaluation
Approaches lead to different results
Results of current Investigations
Controlling parameters have been idenfied by model tests
Uniformity coefficient Cu might not be adequate for a reliable
assessment of internal erosion
Modified (d15Fd85b) mod is promising
Diagrams have been proposed for the evaluation of the internal
erosion stability
Stability of non-cohesive Soils with respect to Internal Erosion
Thank you for your
attention
wwwimpacde
Stability of non-cohesive Soils with respect to Internal Erosion 14
Summary
Problem
Internal erosion
Several approaches exist for the evaluation
Approaches lead to different results
Results of current Investigations
Controlling parameters have been idenfied by model tests
Uniformity coefficient Cu might not be adequate for a reliable
assessment of internal erosion
Modified (d15Fd85b) mod is promising
Diagrams have been proposed for the evaluation of the internal
erosion stability
Stability of non-cohesive Soils with respect to Internal Erosion
Thank you for your
attention
wwwimpacde
Stability of non-cohesive Soils with respect to Internal Erosion
Thank you for your
attention
wwwimpacde