4/14/2012 1 Understanding 10th G.A. Leonards Lecture April 13, 2012 - Purdue U. Soil Properties and Behavior - Recent Developments - J. Carlos Santamarina Georgia Institute of Technology 1921 Born (April 29, Montreal) 1943 BSc ( McGill University ) 1944 Army @ McGill 44-45 Canadian Mines & Resources 1945 Married 45-46 Canadian DoT 1948 MSc (Purdue) Taught Mechanics & Drafting "MUD-LAB" (compaction and shear tests) 6 week trip in the USA (Shannon, Casagrande) Harvard? Caltech? Purdue? 1952 PhD (Purdue): Compacted clay 1952 Assistant Professor 1955 A it P f 1955 Associate Professor 1958 Full Professor 1960 US Citizen 1965 Norman Medal 1976 "Best CE Teacher" 1980 Terzaghi Lecture – Failures 1985 Workshop Dam Failures 1989 Member NAE 1991 Professor Emeritus 1997 Died (February 1)
49
Embed
JCS - Leonards Lecture - SHORT - Purdue Engineering · 4/14/2012 1 Understanding 10th G.A. Leonards Lecture April 13, 2012 - Purdue U. Soil Properties and Behavior - Recent Developments
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
4/14/2012
1
Understanding
10th G.A. Leonards LectureApril 13, 2012 - Purdue U.
Soil Properties and Behavior- Recent Developments -
J. Carlos SantamarinaGeorgia Institute of Technology
1921 Born (April 29, Montreal)
1943 BSc ( McGill University )1944 Army @ McGill 44-45 Canadian Mines & Resources1945 Married45-46 Canadian DoT1948 MSc (Purdue)
Taught Mechanics & Drafting"MUD-LAB" (compaction and shear tests)6 week trip in the USA (Shannon, Casagrande)
Harvard? Caltech? Purdue?
1952 PhD (Purdue): Compacted clay1952 Assistant Professor1955 A i t P f1955 Associate Professor1958 Full Professor
1960 US Citizen1965 Norman Medal
1976 "Best CE Teacher"
1980 Terzaghi Lecture – Failures1985 Workshop Dam Failures1989 Member NAE
1991 Professor Emeritus1997 Died (February 1)
4/14/2012
2
1921 Born (April 29, Montreal)
1943 BSc ( McGill University )1944 Army @ McGill 44-45 Canadian Mines & Resources1945 Married45-46 Canadian DoT1948 MSc (Purdue)
Frozen ground Pavements
1952 PhD (Purdue): Compacted clay1952 Assistant Professor1955 A i t P f Clays: σ-history1955 Associate Professor1958 Full Professor
For all soils [NC and OC], Ko should asymptotically approach unity
Andrawesand El-Sohby 1973Abdelhamid and Krizek 1976Mayne and Kulhawy 1982Feda 1984Kavazanjian and Mitchell (1984)Leonards 1985M i d H t 1993Mesri and Hayat 1993Michalowski 2005Castellanza and Nova 2004
…. among others….
Mount St. Helens – May 18, 1980
Washington State
2,950 meters WSPR
4/14/2012
30
Mount St. Helens – May 18, 1980
USGS
Mount St. Helens – May 18, 1980
4/14/2012
31
Volcanic Ash Soils: Formation
timewind
e= 0.8-1.5
Ss~0.1-1 m2/g
volcanic glass
time
e= 2.0-7.0
Ss=50-to-200 m2/g
hallositeimogolitel h
wind
alophane
ko= ??ko=1-sinφ
USGS
0.00
rain
90% glass bead + 10% NaCl
ko: Experimental Results
0 5
0.6
0.7
ss c
oeffi
cien
t, k
0.02
0.04 Vert
ical
str
0.3
0.4
0.5
0 1000 2000Time (sec)
Late
ral s
tres
Hosung Shin
4/14/2012
32
constz =σ
ko: DEM Simulation
N= 9999 (in 2D) - 8000 (in 3D)
cov particle diameter: 0.25
Interparticle friction: 0.5
Simulation: reduce D or G
0.45
0.50
ent,
K a c
2D - diameter gradually reduced - 20% of particles
ko: DEM Simulation
0.25
0.30
0.35
0.40
Late
ral s
tres
s co
effic
ie
b
0.0 0.5 1.0 1.5
Vertical strain, εz (%)
4/14/2012
33
ko: DEM Simulation – Pressure Solution
Minsu Cha
250m
seabedPolygonal Fault Systems
1kmCartwright (2005)
4/14/2012
34
Soil Properties and Behavior
Lessons Learned
Dissolution and diagenesis: affect ko
Emergent phenomena: shear localization
Complex geo-plumbing
Energy Geotechnology
Resource accumulation (oil, gas)
Gas recovery from hydrate bearing sediments
Leakage (C-sequestration)
Frozen Ground
GAL: PavementsTeton Dam
4/14/2012
35
1965 Highway Research Board "Best Paper Award"
Ice Lenses
Viggiani – Grenoble
Kaolin
4/14/2012
36
Ice Lens Formation Under Stress Boundary
TensionTension
Tension /compression
Compression
Taesup Yun
Hydrate lenses – Pressure cores
Percussion Core - KUB
4/14/2012
37
102
103
Pore-filling
10
WHcap
d'2
NF
σΤπ
=
2π
4102π
Hydrate Bearing Sediments
10-1
100
101
eris
tic p
artic
le s
ize
d 10 [ μ
m]
Lenses
Mt. Elbert
NGHP
102π
10-2 10-1 100 101 10210-4
10-3
10-2
Effective stress σv' [MPa]
Cha
ract
e
Nodules
Blake Ridge
Sheng Dai
Soil Properties and Behavior
FIELD: lens formation = Normal to thermal front
Lessons Learned
MORE GENERAL: also affected by effective stress
Energy Geotechnology
Frozen ground engineering
GREAT
but… generalize
Hydrate distribution
4/14/2012
38
FrictionFriction&
Repetitive Loading
<3500 BC Mesopotamia The wheel
~2750 BC Egyptians Sliding on sand and on wet silt
1452-1519 L. da Vinci T ≠ (apparent contact area)
1663-1705 G. Amontons Re-discovered da Vinci's
1736-1806 C.A. Coulomb Referred to Amontons observations
Strength and Repeated LoadsLarew & Leonards (1962)
Subsidence and VibrationBrumund & Leonards (1972)
F i ti d Vib tiFriction and VibrationBrumund & Leonards (1973)
Undrained Monotonic And Cyclic StrengthAlarcon , Leonards & Chameau (1988)
4/14/2012
39
irc.nrc-cnrc.gc.cawww.dot.ca.gov
Reinforced Earthcoal mine – Australia – guardian.co.uk
100200
Bearing Capacity – N�
factor
10Nγ100
Nγ
10 10 20 30 40
φ °
00 10 20 30 40
φ °
4/14/2012
40
pφ
Macroscale Response in q, p’, e, ε
q
cvφ
ψ p'εa
q=Μp’
'⎛ ⎞
e
ecsecs cs 1kPap 'e e log
kPa⎛ ⎞= −λ ⎜ ⎟⎝ ⎠
Constant Volume Shear0.9
0.7
0.5
sphe
ricity
cvφ
30
40
50
ctio
n an
gle
cv 0.1 0.3 0.5 0.7 0.9
0.3
roundness
10
20
0 0.2 0.4 0.6 0.8 1
Roundness R
CS
fri
cv 42 17 Rφ = −
Gye-Chun Cho
4/14/2012
41
Dilatency Anglee
p'po'
eo
ecs
λ dilative
contractive
Ε
ψ
8
12
16
20
24y
angl
e ψ
[deg
]Kogyuk sand(0~10% fines)Beaufort sand A (2~10% f ines)Beaufort sand B (5% f ines)Banding sand, Hauchipato sand (Castro 1969)Hokksund sand (NGI)Monterey no. 0 sand (Lade 1972)
p po
-4
0
4
8
-0.3 -0.2 -0.1 0.0 0.1
State parameter E
Dila
tanc
y
(Been and Jefferies 1985)
Peak Friction Angle pφ
p cvtan tan tanφ = φ + ψ
p cv 0.8φ = φ + ψ
Taylor 1948:
Bolton 1986:
0.4
0.6
0.8
ak fr
ictio
n si
n(φ
p)
rotation
slippage
(DEM 3D from Thornton 2000), (DEM 2D from Kruyt and Rothenberg 2006), Drained TC( ), Undrained TC( ), Drained TE(�), Undrained TE(�) (DEM-3D from Yimsiri 2001), (experiments) and (DEM 3D from Suiker and Fleck 2004), by the authors.
G.A. Leonards: (1) deepest clear-thinker (2) passion
Emphasized: Understanding
Historical geology
Discontinuities – Weak seams
Multiple working hypotheses + Falsification
Contributions: soils, geo-processes, engineering
Renewed relevance in the context of energy geotechnology
Fascinating field !!
Closing Remarks Workshop on Dam Failures
" Speaking for myself in the future I will be more" Speaking for myself, in the future I will be more humble and more tolerant of the errors and omissions that may befall a fellow engineer ….
and [I will be] a lot more careful before taking a decision that could affect the security of an important structure"