2 ACKNOWLEDGEMENTS - CEProfs Lecture-12Feb2007.pdf · 40.00 45.00 0.00 20.00 40.00 60 ... uu u u...

1

Jean-Louis BRIAUD – Texas A&M University

1

CASE HISTORIES IN SOIL AND ROCK EROSION

Woodrow Wilson Bridge, Brazos River Meander, Normandy Cliffs, and New Orleans Levees

The 9th Ralph B. Peck Lecture

byJean-Louis BRIAUD, PhD, PEProfessor andHolder of the Buchanan ChairTexas A&M University


2

HamnHamn--ChingChing Chen (Texas A&M), Chen (Texas A&M), KuangKuang--An Chang An Chang (Texas A&M), (Texas A&M), AnandAnand GovindasamyGovindasamy (Texas A&M), (Texas A&M), NamgyuNamgyu Park (Texas A&M), Po Park (Texas A&M), Po YehYeh (Texas A&M), (Texas A&M), Jennifer Nicks (Texas A&M), OkJennifer Nicks (Texas A&M), Ok--YounYoun Yu (Texas Yu (Texas A&M), A&M), RemonRemon AbdelmalakAbdelmalak (Texas A&M), (Texas A&M), XingnianXingnianChen (Texas A&M), Rick Chen (Texas A&M), Rick EllmanEllman ((MueserMueser Rutledge), Rutledge), Bea Hunt (Hardesty & Hanover), Stan Davis Bea Hunt (Hardesty & Hanover), Stan Davis (Maryland SHA), Sterling Jones (FHWA), Rune (Maryland SHA), Sterling Jones (FHWA), Rune StoresundStoresund (UC Berkeley), Ray Seed (UC Berkeley), (UC Berkeley), Ray Seed (UC Berkeley), Bob Bea (UC Berkeley), Tom Dahl (Bob Bea (UC Berkeley), Tom Dahl (TxDOTTxDOT), Bob ), Bob Warden (Texas A&M), Mark Everett (Texas A&M), Warden (Texas A&M), Mark Everett (Texas A&M), (ABMC), Phil Buchanan (Buchanan Soil Mechanics) (ABMC), Phil Buchanan (Buchanan Soil Mechanics)

ACKNOWLEDGEMENTSACKNOWLEDGEMENTS

2


3

••1972 1972 -- TerzaghiTerzaghi and Peckand Peck

••1975 1975 -- PhD letterPhD letter

••1993 1993 -- Buchanan LectureBuchanan Lecture

••1998 1998 -- AdministrationAdministration

••2006 2006 -- Peck LecturePeck Lecture

Professor PECKProfessor PECKFor his influence on my careerFor his influence on my career


4

1.1.Fundamentals of Soil ErosionFundamentals of Soil Erosion

2.2.Woodrow Wilson BridgeWoodrow Wilson Bridge

3.3.Brazos River MeanderBrazos River Meander

4.4.Normandy CliffsNormandy Cliffs

5.5.New Orleans LeveesNew Orleans Levees

3


5

Input to an erosion problemInput to an erosion problem

••Soil (Erodibility)Soil (Erodibility)

••Water (Velocity)Water (Velocity)

••Geometry (Dimensions)Geometry (Dimensions)


6No Flow Condition

4


7Flow Condition


8

5


9

Relationship between the erosion rate and the velocity of the water near the soil-water interface.

Relationship between the erosion rate and the shear stress at the soil-water interface.

( )Z f τ=

DEFINITION OF SOIL ERODIBILITY

Constitutive Law for Soil Erosion


10

EFA EFA -- EROSION FUNCTION APPARATUSEROSION FUNCTION APPARATUS

6


11


12

Scour Rate vs Shear Stress

0.01

0.10

1.00

10.00

100.00

1000.00

10000.00

0.1 1.0 10.0 100.0

Shear Stress (N/m2)

Scou

r R

ate

(mm

/hr)

Sand D50=0.3 mm

Scour Rate vs Velocity

0.01

0.10

1.00

10.00

100.00

1000.00

10000.00

0.1 1.0 10.0 100.0

Velocity (m/s)

Scou

r R

ate

(mm

/hr)

Sand D50=0.3 mm

EROSION FUNCTION FOR A FINE SAND

7


13

Scour Rate vs Shear Stress

0.01

0.10

1.00

10.00

100.00

0.1 1.0 10.0 100.0

Shear Stress (N/m2)

Scou

r R

ate

(mm

/hr)

Porcelain Clay PI=16%Su=23.3 Kpa

Scour Rate vs Velocity

0.01

0.10

1.00

10.00

100.00

0.1 1.0 10.0 100.0

Velocity (m/s)

Scou

r R

ate

(mm

/hr)

Porcelain Clay PI=16%Su=23.3 Kpa

EROSION FUNCTION FOR A LOW PI CLAY


14NIAGARA FALLS11000 m of lateral erosion from Lake Ontario

towards Lake Erie in 12000 years or 0.1 mm/hr

From Google Earthhttp://www.iaw.com/~falls/origins.html

http://www.samizdat.qc.ca/cosmos/origines/niagara/niagara.htm

Lake Erie

Lake Ontario

Niagara River1841

1841

2006

Niagara Falls

8


15GRAND CANYON

1600 m of vertical erosion by the Colorado Riverin 10 Million years or 0.00002 mm/hr


16

If your faucet If your faucet drips on a drips on a pebble for 20 pebble for 20 million years,million years, will there be will there be

a hole in the a hole in the pebble?pebble?

9


17

ERODIBILITY CATEGORIES (velocity)ERODIBILITY CATEGORIES (velocity)

0.1

1

10

100

1000

10000

100000

0.1 1.0 10.0 100.0

Velocity (m/s)

ErosionRate

(mm/hr)

Very HighErodibility

I

HighErodibility

IIMedium

Erodibility III

LowErodibility

IV

Very LowErodibility

V


18

ERODIBILITY CATEGORIES (shear)ERODIBILITY CATEGORIES (shear)

0.1

1

10

100

1000

10000

100000

0 1 10 100 1000 10000 100000Shear Stress (Pa)


I

HighErodibility

IIMedium

Erodibility III Low

Erodibility IV

Very LowErodibility

V

Erosion Rate

(mm/hr)

10


19

CRITICAL VELOCITY CRITICAL VELOCITY vsvs GRAIN SIZEGRAIN SIZE

0.01

0.1

1

10

100

0.0001 0.001 0.01 0.1 1 10 100 1000 10000

Mean Grain Size, D50 (mm)

Critical Velocity,

Vc

(m/s)

CLAY SILT SAND GRAVEL RIP-RAP

Vc = 0.35 (D50)0.45

Vc = 0.1 (D50)-0.2

Vc = 0.03 (D50)-1

US Army Corps of Engineers EM 1601


20

CRITICAL SHEAR STRESS CRITICAL SHEAR STRESS vsvs GRAIN SIZEGRAIN SIZE

0.01

0.1

1

10

100

1000

10000

0.0001 0.001 0.01 0.1 1 10 100 1000 10000

Mean Grain Size, D50 (mm)

Critical ShearStress,

τc

(N/m2)

US Army Corps of Engineers EM 1601

CLAY SILT SAND GRAVEL RIP-RAP

Curve proposed by Shields (1936)

τc = D50

τc = 0.006 (D50)-2

τc = 0.05 (D50)-0.4

11


21

9. Soil clay minerals10. Soil dispersion ratio11. Soil cation exchange cap12. Soil sodium absorption rat13. Soil pH14. Soil temperature15. Water temperature16. Water salinity17. Water pH

Erodibility depends on soil propertiesErodibility depends on soil properties

1. Soil water content2. Soil unit weight 3. Soil plasticity index4. Soil undrained shear str.5. Soil void ratio6. Soil swell7. Soil mean grain size8. Soil percent passing #200


22

NO SIMPLE CORRELATION !

CSS vs.#200

R2 = 0.1306

0.00

5.00

10.00

15.00

20.00

25.00

0.00 20.00 40.00 60.00 80.00 100.00 120.00

# 20 0 ( %)

CSS vs. Su

R2 = 0.1093

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00

Su(kPa)

CSS

(Pa)

12


23

EFA test onCreamy Peanut Butter

Su = 1.8 kPaVc = 1.4 m/s

0.1

1

10

100

1000

10000

100000

0.1 1.0 10.0 100.0

Velocity (m/s)


I

HighErodibility

II

MediumErodibility

III

LowErodibility

IV

Very LowErodibility

V

Erosion Rate

(mm/hr)

0.1

1

10

100

1000

10000

100000

0 1 10 100 1000 10000 100000

Shear Stress (Pa)


I

HighErodibility

IIMedium

Erodibility III

LowErodibility

IV

Very LowErodibility

V

Erosion Rate

(mm/hr)


24

.

2 2 2

m n pcZ

u u u uτ τ τ σα β δρ ρ ρ

⎛ − ⎞ ⎛ ⎞ ⎛ ⎞Δ Δ= + +⎜ ⎟ ⎜ ⎟ ⎜ ⎟

⎝ ⎠ ⎝ ⎠ ⎝ ⎠Mean Net

Shear Stress

Shear Stress

Turbulence

Normal Stress

Turbulence

.( )Z f τ=

Constitutive Law for Soil Erosion

13


25






26

Shear Stress Applied by Water

dz

14


27


28

15


29

Flow HydrographFlow Hydrograph


30

Velocity & Water Depth HydrographVelocity & Water Depth Hydrograph

16


31

Obtaining a design flood valueObtaining a design flood valueFlood-frequency curve based on Original Hydrograph

(1931-1999)

y = -2491.6Ln(x) + 12629R2 = 0.9563

0

5000

10000

15000

20000

0.1110100

Percent probability of exceedance in X years

Stre

amflo

w (m

3 /sec

)

100year flood: 12629m3/s500year flood: 16639m3/s


32

Probably of Exceedance Probably of Exceedance -- PoEPoE

100 yr 100 yr 53% 53% PoEPoE, , vv100100 = 2.8* = 2.8* m/sm/s500 yr 500 yr 13.9% 13.9% PoEPoE, , vv500500 = 3.25* = 3.25* m/sm/s10000 yr10000 yr 0.75% 0.75% PoEPoE, , vv1000010000 = 3.95* = 3.95* m/sm/s

** Example for Woodrow Wilson Bridge for 75 year design life.Example for Woodrow Wilson Bridge for 75 year design life.

Structural Eng. operate at a Prob. of Exceedance of 0.1%?Structural Eng. operate at a Prob. of Exceedance of 0.1%?Geotechnical Eng. operate at a Prob. of Exceedance of 1%?Geotechnical Eng. operate at a Prob. of Exceedance of 1%?Hydraulic Eng. operate at a Prob. of Exceedance of 10%?Hydraulic Eng. operate at a Prob. of Exceedance of 10%?

17


33






34

PIER SIZE & SHAPE for PIER SCOUR

18


35

CONTRACTION RATIO for CONTRACTION SCOUR


36

RADIUS OF CURVATURE FOR MEANDERS

19


37

WAVE ATTACK FOR CLIFF EROSION


38

OVERTOPPING OF LEVEES

20


39

RANS EquationsRANS EquationsContinuity equationContinuity equation

Momentum (RANS) EquationsMomentum (RANS) Equations

Energy EquationEnergy Equation

0)U(t m,

m =+∂∂ ρρ

( ) ( )m,

in,

mnm,

imimmnmimn

nmlmn

ilimm,

im,

mi

Ugpgg

Ueg2RUUt

U

μξΩΩξΩΩρ

Ωρρ

+−=−+

+⎟⎟⎠

⎞⎜⎜⎝

⎛++

∂∂

( ) ( )

( ){ } uuUUgguuUU DtDpKTgTuTU

tTC

jn

im

jn

im

mnij

nm

mn

nm

mn

mnmn

mm

mm

p

,,,,,,,,

,,,,

+++−=Φ

Φ++=⎥⎦⎤

⎢⎣⎡ ′++∂∂

μ

ρ


40

Reynolds StressesReynolds StressesTransport EquationsTransport Equations

ProductionProduction

Diffusion by uDiffusion by umm

Diffusion by pDiffusion by p′′

Viscous DiffusionViscous Diffusion

PressurePressure--StrainStrain

DissipationDissipation

ijijijv

ijp

iju

ijijm,

mij

DDDPRUt

R εΦ −++++=+∂∂

jn,

im,

mnij

im,

jmjm,

imij

ijmn,

mnijv

m,jim

m,ijmij

p

m,jimij

u

injljnilmlmn

im,

jmjm,

imij

uug2

)ugug)(/'p(

RgD

)/ρ'pu(g)/ρ'pu(gD

)uuu(D

)RgRg(e2

)URUR(P

νε

ρΦ

ν

Ω

=

+=

=

−−=

−=

+−

+−=

21


41

TwoTwo--Layer kLayer k--εε ModelModel•• Outer LayerOuter Layer (Fully Turbulent Region)(Fully Turbulent Region)

( )ρεεεσμμεερ

ρεσμμρ

εεεε

2b31

m,

n,tmn

m,m

b

m,

n,k

tmnm,

m

CPCPCk

gUt

PPkgkUtk

−++⎭⎬⎫

⎩⎨⎧

⎟⎟⎠

⎞⎜⎜⎝

⎛+=⎟

⎠⎞

⎜⎝⎛ +∂∂

−++⎭⎬⎫

⎩⎨⎧

⎟⎟⎠

⎞⎜⎜⎝

⎛+=⎟

⎠⎞

⎜⎝⎛ +∂∂

• Inner Layer (Near-Wall Region)

( )[ ] ( )[ ] AR1yC ;AR1yC

kC ;k

PPkgkUtk

yy

t

3/2

b

m

nk

tmnm

m

εεμμ

μμε

ρμε

ρεσμμρ

/exp/exp

,

,,

−−=−−=

==

−++⎭⎬⎫

⎩⎨⎧

⎟⎟⎠

⎞⎜⎜⎝

⎛+=⎟

⎠⎞

⎜⎝⎛ +∂∂

• Compute wall shear stress directly without wall function approximation


42

( )bb

b

2 2 2

,

0 ,

; q U

b c c

c

b

cZ

q V Wn

τ τ τ τ

τ τ

τ μ

⎧ − >⎪= ⎨≤⎪⎩

∂= = + +

∂

Scour Rate EquationScour Rate Equation

•• Critical shear stress Critical shear stress ττcc

•• Streambed shear stress Streambed shear stress ττbb

•• Both the initiation and termination of scour process Both the initiation and termination of scour process are determined by the critical shear stressare determined by the critical shear stress

•• The scourThe scour--rate vs. shear stress curves are siterate vs. shear stress curves are site--specific and must be determined from the specific and must be determined from the measurementsmeasurements

22


43


44

23


45


46






24


47

Woodrow Wilson Bridge and Pier Scour


48

60% of BRIDGE FAILURES60% of BRIDGE FAILURESARE DUE TO SCOURARE DUE TO SCOUR

0

100

200

300

400

500

600

700

800

900

1000

Con

stru

ctio

n

Con

cret

e

Det

erio

ratio

n

Eart

hqua

ke

Nat

ural

Stee

l

Fire

Mis

c.

Ove

rloa

d

Col

lisio

n

Hyd

raul

ic

Cause

Num

ber o

f Fai

lure

s fr

om19

66 to

200

5 (1

502

Tota

l)

0%

10%

20%

30%

40%

50%

60%

Perc

ent

25


49Schoharie Creek Bridge Failure – 17 April 198710 people died


50

26


51

OldWoodrow Wilson

Bridge


52

NewWoodrow Wilson

Bridge

27


53

SOIL LAYERS


54

STRATIGRAPHY

TO SCALE

NOT TO SCALE

28


55



56Soft organic clay, Low Su (22 kPa)Vc = 0.5 to 2.2 m/s; higher rates

Hard mineral clay, High Su (130 kPa)Vc = 0.2 m/s; lower rates

29


57


58Obtaining the 100 yr and 500 yr floodObtaining the 100 yr and 500 yr floodFlood-frequency curve based on Original Hydrograph

(1931-1999)

y = -2491.6Ln(x) + 12629R2 = 0.9563

0

5000

10000

15000

20000

0.1110100

Percent probability of exceedance in X years

Stre

amflo

w (m

3 /sec

)

100year flood: 12629m3/s500year flood: 16639m3/s

30


59


60

Bascule Pier Layout (M1)Direction of Flow

Pedestal

Arch Rib

39.2

m

26.5 m

1.8 m Dia. open ended steel pipe pile

EL. 4 m (500 yr)EL. 3 m (100 yr)

EL. 0.6 m (Ave.)

EL. -10.5 m (River Bottom)

Estimated Tip EL. -68.6 m

58.1

m5.

9 m

31


61

Bascule Pier with Ring Layout (M1)

Arch Rib

EL. 0.6 m (Ave.)




1.4 m Dia. open ended steel pipe pile

[SECTION A]

A A

Concrete fender ring with composite marine timber facing


62Hydrograph (Add 500year flood)

0

3000

6000

9000

12000

15000

18000

1960 1970 1980 1990 2000

Time (Year)

Scour Depth Vs. Time (Add 500year flood)

0

2

4

6

8

10

12

1960 1970 1980 1990 2000

Time (Year)

Scou

r Dep

th (m

)

Scou

r Dep

th (m

)Fl

ow (m

3 /s)

32


63

SCALED FLUME TESTS

FHWA

PIER ONLY


64

SCALED FLUME TESTS (FHWA)PIER and RING (Final Design)

33


65

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

HEC-18Sand(Pile

Width)

HEC-18Sand(PileCap)

Salim-Jones

HEC-18Clay

(TexasA&M)

ErodibilityIndex

LargeScaleFlumeTest

SmallScaleFlumeTest

SelectedScour

Scou

r Dep

th (m

Comparison of Scour PredictionsBascule Pier M1 (500yr Flood)


66

NOT TO SCALENEW BRIDGE WITH STRATIGRAPHY

TO SCALE

34


67

PIER 1E

OldWoodrowWilsonBridge


68

35


69Predicted Hydrograph (75year)

0

3000

6000

9000

12000

15000

18000

0 15 30 45 60 75

Time (Year)

Stre

amflo

w (m

3 /s)

Predicted Scour Depth Vs. Time

0

2

4

6

8

10

12

0 15 30 45 60 75

Time (Year)

Scou

r Dep

th (m

)

Probability of exceedance of a scour depth

0 .0 1

0 .1

1

1 0

1 0 0

5 7 .5 1 0 1 2 .5 1 5

d (m)

R(d

) (%

)

L t= 5 0 ye a rL t= 7 5 ye a rL t= 1 0 0 ye a rL t= 1 5 0 ye a r

Prob

abili

ty o

f Ex

ceed

ance

Scour Depth (m)


70

Static Load Test

36


71

StatnamicLoad Test


72

Pile for Bascule Pier (M1)EL. 4 m (500 yr)

EL. -68.6 m (Estimated Pile Tip)

12000 kN

618 kNEL. 3 m (100 yr)EL. 0.6m (Ave.)


Alluvial Soil

River

Glacial Sand

Cretaceous Clay

Open Ended Steel Pipe Pile (D = 1.8 m, L = 64 m)

13.0 m

45.1 m

M1: Earthquake

M2: Vessel Collision

M3~M10: Wind Load

5.9 m

500 yr scour depth

37


73Comparison

Soft Clay

Loose Sand

Hard Clay

1.8 m

19.2 m

33 yr scour depth(measured)1.6 m/s velocity

Pile SizeD = 1.8 m, L = 64 m

River

Pile SizeD = 0.5 m, L = 21 m

500 yr scour depth3.2 m/s velocity

13.0 m

45.1 m

5.9 m

[New Pile for Bascule Pier] [Old Pile for Bascule Pier]

154 PILES78 PILES


74

38


75


76

39


77Demolition of Old Woodrow Wilson Bridge


78






40


79

Brazos River and MeanderMigration


80

FM159

SH105

Navasota

Brenham

198119952006

0 400 (m)

NORTH

41


81

PROBLEM = CHANNEL

MIGRATION

1969 1999


82

MEASURED CHANNEL MOVEMENT

0

50

100

150

1980 1985 1990 1995 2000 2005 2010

Time (year)

Cha

nnel

Mov

emen

t (m

)

42


83

BrazosRiver

at SH105

FLOW


84

Undercutting

Sloughing

Deposition

43


85

MethodologyFor

Predicting Meander Migration

•Soil erosion function

•Water velocity hydrograph (risk)

•Geometry


86

Large Scale Flume Tests in Sand

1m

44


87

Large Scale Flume Tests in Clay

1m


88


45


89

Numerical Simulations


90MEANDER GEOMETRY PARAMETERS

R

W

θ

R

φ

φ

A

M(t)

46


91

MEANDER RESONANCE

(b)

(a)

(c)

R/W

R/W

R/W

(b)

(a)

0 2 4 6 8R/W

M/v

(a)

(b)

(c)

.


92

Main Screen of MEANDER

47


93

Sampling Locations


94

300

0 100 200 300 400 500 600

1951 Profile2006 Profile(m)

(m)

TO SCALE

To Brenham (West)To Navasota (East)

Erosion

Deposition

1951 Profile2006 Profile

0 100 400200 300 500 600

00

30

20

10

(m)

(m)

NOT TO SCALE

Cross-sectional Profile at Meandering Bend

NORTH

WEST

48


95

Soil Layers at B-2To Brenham (West)To Navasota (East)

2006 Profile

Hard Brown Clay

Stiff Brown Silty Clay

Very Dense BrownSilty Sand (SM)

IV IIII IIV

ErodibilityCategory

Depth(m)

15.0

13.1

8.0

6.0

0

Very Dense Sand(SP)NORTH


96


49


97

EFA Test Results: Erosion Rate vs. Shear Stress

0.1

1.0

10.0

100.0

1000.0

0.1 1.0 10.0 100.0Shear Stress (N/m2)

Eros

ion

Rat

e (m

m/h

r)B1-(30-32)

B1-(40-42)

B1-(48-50)

B2-(30-32)

B2-(38-40)

B2-(48-50)

B3-(10-12)

B3-(20-22)

B3-(30-32)

B3-(38-40)

B3-(48-50)

Upper Bound

Low er Bound

Chosen forPrediction


98

EFA Test Results: Erodibility Categories

0.1

1

10

100

1000

10000

100000

0.1 1.0 10.0 100.0

Velocity (m/s)

Eros

ion

Rat

e (m

m/h

r)

B1-(30-32) B1-(40-42) B1-(48-50) B2-(30-32) B2-(38-40) B2-(48-50)

B3-(10-12) B3-(20-22) B3-(30-32) B3-(38-40) B3-(48-50)


I

HighErodibility

IIMedium

ErodibilityIII

LowErodibility

IV

Very LowErodibility

V

50


99Water hydrograph

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

June-57 June-62 June-67 June-72 June-77 June-82 June-87 June-92 June-97 June-02 June-07

Time (year)

Dai

ly D

isch

arge

(m3 /s

)

1957 1962 1967 1972 1977 1982 1987 1992 1997 2002 2007

Discharge

0.0

0.5

1.0

1.5

2.0

2.5

3.0

June-57 June-62 June-67 June-72 June-77 June-82 June-87 June-92 June-97 June-02 June-07

Time (year)

Dai

ly M

ean

Velo

city

(m/s

)

1957 1962 1967 1972 1977 1982 1987 1992 1997 2002 2007

Velocity


100

FM159

SH105

Navasota

Brenham

19811995

2006

0 400 (m)

NORTH

51


101


102

52


103


104

Highway 105

LegendRiver (Today)

50% Probability that river will reach here or further10% Probability that river will reach here or further1% Probability that river will reach here or further0.1% Probability that river will reach here or further

ProbabilisticPredictionsAt 20 years

53


105


106

There is a 1% probability that the river will move There is a 1% probability that the river will move outward outward 23.7m or more23.7m or more..

54


107







108

Pointe du Hoc and Cliff Erosion

World War II Invasion SiteJune 6th, 1944

55


109

25 APRIL 194413 MAY 194422 MAY 19444 JUNE 19445 JUNE 19446 JUNE 1944

http://b26marauder.com/322nd/b26inflight.html

HEAVY BOMBARDEMENT OF POINTE DU HOC


110

56


111CLIMBING THE CLIFFS AT LOCATIONS OF BOMB IMPACT

General Earl Rudder and 200 Rangers


112POINTE DU HOC TODAY

57


113Approximately 10 m of erosion since 1945Average cliff erosion rate = 0.167 m/yr


114

Sandown Bay in Isle of Wight south of UK (2003 ~ 2006) Maximum Wave Height

0

1

2

3

4

5

6

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Month

Max

imum

Wav

e H

eigh

t (m Hmax (m)

58


115

Fluctuation of high and low tide levelfrom April to September, 2006 at Pointe du Hoc

Tide Levels

01234

5678

1-Apr-06 1-May-06 31-May-06 30-Jun-06 30-Jul-06 29-Aug-06 28-Sep-06

Date

Leve

l (m

)

Maximum daily tide level

Minimum daily tide level


116

Sketch cross section of the cliff and Observation Post

59


117

Inside the Observation PostInside the Observation Post


118Drilling Rig

60


119

SiltyClay

Fractured Limestone

Very hard Sandstone


120

STRATIGRAPHY

61


121

General stratigraphy near Observation Post.


122

ELECTRICAL RESISTIVITY PROFILES

62


123



124

0.1

1

10

100

1000

10000

100000

0.1 1.0 10.0 100.0Velocity (m/s)

Eros

ion

Rat

e(m

m/h

r)

Clay-B5-(6.40-7.25m)


IHigh

Erodibility II

MediumErodibility

IIILow

Erodibility IV

Very LowErodibility

V

Silty Clay (surface soil) erosion function50 mm/hr for 1 m/s or 438 m/yr

63


125

0.0330.0180.024Erosion Rate

(mm/hr)

30.63727.70328.719Shear stress

(Pa)

3.5923.6113.676Velocity(m/sec)

Marly lime-stone

SandstoneLimestone

Rock erosion rates0.025 mm/hr at 3.6 m/s or 0.22 m/yr


126

Erosion of cliff base

Caverns below the Observation Post

64


127

CLIFF BASE EROSION


128Overhang with separation

of the rock block from the rock mass

65


129

Rock block removal analysis


130Required Wave Head (Hwave) to Move a Rock Block

0

1

2

3

4

5

6

0 1 2 3 4

Rock Block Size (m)

Wav

e He

ad (m

)

φ=30φ=45

66


131

FINITE ELEMENT MESH TO OBTAINSTRESSES IN ROCK NEAR CLIFF


132

0

5

1 0

1 5

2 0

2 5

3 0

-6 0 -4 0 -2 0 0 2 0 4 0 6 0

H o r i z o n ta l S tr e ss (k P a )

Ele

vatio

n fr

om S

ea L

evel

(m)

1 m E ro s io n2 m E ro s io n3 m E ro s io n4 m E ro s io n5 m E ro s io n

C o m p r e ssi o n T e n si o n

Horizontal stress distribution in rock massMaximum tensile stress = 1/10th of intact rock tensile strength

67


133

TENSILESTRENGTH

TEST


134

23.633.8324.534.52MarlyMarly LimestoneLimestone

23.151.4823.494.55SandstoneSandstone

24.143.1224.903.36LimestoneLimestone

γγdrydrywwccγγttσσtt

(kN/m(kN/m33))(%)(%)(kN/m(kN/m33))((MPaMPa))SampleSample

AVERAGE TENSILE STRENGTH AND TEST RESULTS

68


135

L

22m L

H

Pt

t

L

H

22m L

H

Pt

t

P

CANTILEVER BEAM ANALYSIS


136Massive collapse about 300m west of the Observation Post

Block length (cavern depth or cantilever length) is about 4 m

69


137Proposed remediation to reopen the Observation Post


138






70


139

New Orleans Levees and Overtopping Erosion


140

USA BUDGET = 2500 Billion $ / year

Katrina damage = 125 Billion $

Katrina damage = 5% of USA budget / yr

71


141USA Population = 300,000,000Deaths per year = 2,500,000

Deaths during Katrina = 1500 or 0.06%Cancer = 600,000 / yr or 24 %

20059 5 5 1 9 6 0 1 9 6 5 1 9 7 0 1 9 7 5 1 9 8 0 1 9 8 5 1 9 9 0 1 9 9 5 2 0 0 0 2 0 0

600

01955

DEATHSPER YR AND PER 100,000

Heart Attack

Cancer

Stroke


142On 29 August 2005, Hurricane Katrina hit the Coast of the Gulf of Mexico

72


143

Hurricane = 250 miles in diameterHurricane = 250 miles in diameter

Travel speed = 25 mphTravel speed = 25 mph

Time on a levee or a bridge = 10 hoursTime on a levee or a bridge = 10 hours

Number of wave cycles = 6000Number of wave cycles = 6000


144

Created by friction between the windand the water, a storm surge develops

73


145STORM SURGE

8.5 m

4.6 m

3.0 m


146

74


147


148

75


149


150

76


151


152

77


153

TO SCALE

NOT TO SCALE


154

78


155


156

Flood Return PeriodFlood Return Periodused in design in the Netherlands (levees)used in design in the Netherlands (levees)1/10,000 for most populated areas1/10,000 for most populated areas1/4,000 for less populated areas1/4,000 for less populated areas

Flood Return PeriodFlood Return Periodused in design in the USA (bridges)used in design in the USA (bridges)1/500 with Factor of Safety of 11/500 with Factor of Safety of 11/100 with normal Factor of Safety1/100 with normal Factor of Safety

Overtopping of levees not considered in levee Overtopping of levees not considered in levee design in the USAdesign in the USA

79


157


158

EFA - EROSION FUNCTION APPARATUS

80


159

0.11.0

10.0100.0

1000.010000.0

100000.0

0.1 1.0 10.0

Shear Stress (Pa)

Ero

sion

Rat

e(m

m/h

r) NO-S-4-LightCompactionDepth(ft):0 - 1D50 = -mm


160

0.1

1.0

10.0

0.1 1.0 10.0 100.0 1000.0

Shear Stress (Pa)

Ero

sion

Rate

(mm

/hr) S3-B3-(0-1ft)

Depth(ft):0-1Su = 94kPa

81


161EFA TEST RESULTS EFA TEST RESULTS -- Erosion rate Erosion rate vsvs velocityvelocity

0.1

1

10

100

1000

10000

100000

0.1 1.0 10.0 100.0Velocity (m/s)S1-B1-(0-2ft)-TW S1-B1-(2-4ft)-SW S2-B1-(0-2ft)-TWS2-B1-(2-4ft)-SW S3-B1-(2-4ft)-SW S3-B2-(0-2ft)-SWS3-B3-(0-1ft)-SW S4-(0-0.5ft)-LC-SW S4-(0-0.5ft)-HC-SWS5-(0-0.5ft)-LT-SW S6-(0-0.5ft)-LC-SW S7-B1-(0-2ft)-TWS7-B1-(2-4ft)-SW S8-B1-(0-2ft)-TW S8-B1-(2-4ft)-L1-SWS8-B1-(2-4ft)-L2-SW S11-(0-0.5ft)-LC-TW S11-(0-0.5ft)-HC-TWS12-B1-(0-2ft)-TW S12-B1-(2-4ft)-SW S15-Canal Side-(0-0.5ft)-LC-SWS15-CanalSide-(0-0.5ft)-HC-SW S15-Levee Crown-(0-0.5ft)-LT-SW S15-Levee Crown-(0.5-1.0ft)-LT-SW


I

HighErodibility

II MediumErodibility

III

LowErodibility

IV

Very LowErodibility

V

Erosion Rate

(mm/hr)


162EFA TEST RESULTS EFA TEST RESULTS -- Erosion rate Erosion rate vsvs shear stressshear stress

0.1

1

10

100

1000

10000

100000

0 1 10 100 1000 10000 100000Shear Stress (Pa)

S1-B1-(0-2ft)-TW S1-B1-(2-4ft)-SW S2-B1-(0-2ft)-TWS2-B1-(2-4ft)-SW S3-B1-(2-4ft)-SW S3-B2-(0-2ft)-SWS3-B3-(0-1ft)-SW S4-(0-0.5ft)-LC-SW S4-(0-0.5ft)-HC-SWS5-(0-0.5ft)-LT-SW S6-(0-0.5ft)-LC-SW S7-B1-(0-2ft)-TWS7-B1-(2-4ft)-SW S8-B1-(0-2ft)-TW S8-B1-(2-4ft)-L1-SWS8-B1-(2-4ft)-L2-SW S11-(0-0.5ft)-LC-TW S11-(0-0.5ft)-HC-TWS12-B1-(0-2ft)-TW S12-B1-(2-4ft)-SW S15-Canal Side-(0-0.5ft)-LC-SWS15-CanalSide-(0-0.5ft)-HC-SW S15-Levee Crown-(0-0.5ft)-LT-SW S15-Levee Crown-(0.5-1.0ft)-LT-SW


IHigh

Erodibility II

MediumErodibility

IIILow

Erodibility IV

Very LowErodibility

V

Erosion Rate

(mm/hr)

82


163

NUMERICAL SIMULATIONNUMERICAL SIMULATION


164

t = 0.80 sec

t = 1.28 sec

t = 1.60 sec

t = 1.92 sec

t = 2.39 sec

83


165SHEAR STRESSES ON LEVEE SURFACESHEAR STRESSES ON LEVEE SURFACE


166EFA TEST RESULTS EFA TEST RESULTS -- Erosion rate Erosion rate vsvs shear stressshear stress

0.1

1

10

100

1000

10000

100000

0 1 10 100 1000 10000 100000Shear Stress (Pa)

S1-B1-(0-2ft)-TW S1-B1-(2-4ft)-SW S2-B1-(0-2ft)-TWS2-B1-(2-4ft)-SW S3-B1-(2-4ft)-SW S3-B2-(0-2ft)-SWS3-B3-(0-1ft)-SW S4-(0-0.5ft)-LC-SW S4-(0-0.5ft)-HC-SWS5-(0-0.5ft)-LT-SW S6-(0-0.5ft)-LC-SW S7-B1-(0-2ft)-TWS7-B1-(2-4ft)-SW S8-B1-(0-2ft)-TW S8-B1-(2-4ft)-L1-SWS8-B1-(2-4ft)-L2-SW S11-(0-0.5ft)-LC-TW S11-(0-0.5ft)-HC-TWS12-B1-(0-2ft)-TW S12-B1-(2-4ft)-SW S15-Canal Side-(0-0.5ft)-LC-SWS15-CanalSide-(0-0.5ft)-HC-SW S15-Levee Crown-(0-0.5ft)-LT-SW S15-Levee Crown-(0.5-1.0ft)-LT-SW


IHigh

Erodibility II

MediumErodibility

IIILow

Erodibility IV

Very LowErodibility

V

Erosion Rate

(mm/hr)

84


167

LEVEES LEVEES –– FAILED and NOT FAILEDFAILED and NOT FAILED

0.1

1

10

100

1000

10000

100000

0.1 1.0 10.0 100.0Velocity (m/s)S2-B1-(0-2ft)-TW S2-B1-(2-4ft)-SW S3-B1-(2-4ft)-SW

S3-B2-(0-2ft)-SW S3-B3-(0-1ft)-SW S4-(0-0.5ft)-LC-SW

S5-(0-0.5ft)-LT-SW S6-(0-0.5ft)-LC-SW S15-Canal Side-(0-0.5ft)-LC-SW

S15-CanalSide-(0-0.5ft)-HC-SW S15-Levee Crown-(0-0.5ft)-LT-SW S15-Levee Crown-(0.5-1.0ft)-LT-SW


I

HighErodibility

II MediumErodibility

III

LowErodibility

IV

Very LowErodibility

V

Erosion Rate

(mm/hr)

Note:- Solid circles = levee breaches- Empty circles = no levee damage


168

LEVEE OVERTOPPING CHARTLEVEE OVERTOPPING CHART

0.1

1

10

100

1000

10000

100000

0.1 1.0 10.0 100.0

Velocity (m/s)

ErosionRate

(mm/hr)


I

HighErodibility

IIMedium

Erodibility III

LowErodibility

IV

Very LowErodibility

V

TRANSITIONZONE

PRONE TOFAILURE BY

OVERTOPPING

PRONE TO RESIST

OVERTOPPING

85


169

••Fundamentals of Soil ErosionFundamentals of Soil Erosion

••Woodrow Wilson BridgeWoodrow Wilson Bridge

••Brazos River MeanderBrazos River Meander

••Normandy CliffsNormandy Cliffs

••New Orleans LeveesNew Orleans Levees


170

•Scour and erosion is a large field of civil engineering (bridge scour, cliff erosion, levee erosion, meander migration, piping in dams, construction sites surface erosion, highway embankment surface erosion, beach erosion).

•Geotechnical engineers need to get involved as the soil and rock side of the field (practice andresearch) is seriously lagging behind the hydraulic side………………………………………….

CONCLUSION

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