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Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
1 Educational session Geosynthetics in reinforced soil structures
Educational session
Geosynthetics in reinforced soil structures
AOR Dipl.-Ing. Gerhard Bräu
Univ.-Prof. Dr.-Ing. Martin Ziegler Geotechnik im Bauwesen, RWTH Aachen University
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
2 Educational session Geosynthetics in reinforced soil structures
Educational session
Geosynthetics in reinforced soil structures
1. Introduction: Functioning of geosynthetic reinforcement in soil (M. Ziegler)
2. Introduction: Overview of EBGEO (G. Bräu)
4. Example: Earth dam (G. Bräu)
3. Example: Geosynthetic reinforced retaining wall (M. Ziegler)
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
3 Educational session Geosynthetics in reinforced soil structures
Supported by
1. Introduction
2. Applications of Ground Reinforcement
3. Interaction between Reinforcement and Soil
Functioning of geosynthetic reinforcement in soil
Univ.-Prof. Dr.-Ing. Martin Ziegler Geotechnik im Bauwesen, RWTH Aachen University
4. Summary and Conclusions
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
4 Educational session Geosynthetics in reinforced soil structures
1. Introduction
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
5 Educational session Geosynthetics in reinforced soil structures
1. Introduction
http://www.baunetzwissen.de/objektartikel/Beton-Haus-fuer-Musik-und-Musiktheater-in-Graz-A_775168.html?img=3&layout=galerie
http://bauwiki.tugraz.at/bin/view/Baulexikon/BeWehrung
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
6 Educational session Geosynthetics in reinforced soil structures
1. Introduction
Courtesy Huesker
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
7 Educational session Geosynthetics in reinforced soil structures
1. Introduction
Temple Ziggurat in Aqar Quf (Mesopotamia, near Bagdad) 1500-1300 B.C.
Stabilisation of foundation and brick walls with reed mats
Vogt/TUM
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
8 Educational session Geosynthetics in reinforced soil structures
1. Introduction http://upload.wikimedia.org/wikipedia/commons/3/33/Pantheon_innen.jpg
http://de.wikipedia.org/w/index.php?title=Datei:Roemerkanal_buschhoven.jpg&filetimestamp=20050602123409
Invention of Opus Caementitium - ancestor of concrete (1 century AD) Pantheon Rome
Segment of the 116km long old Roman Eifel water-channel (1 cent. AD)
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
9 Educational session Geosynthetics in reinforced soil structures
2. Applications
Reinforcement of base course
Foundation cushion
Railway and roadworks
Embankments
Bridge abutment Steep slopes
Applications of ground reinforcement
Pile foundation Bridging of sinkholes
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
10 Educational session Geosynthetics in reinforced soil structures
2. Applications
Retaining wall with geogrids (Netlon LTD. UK)
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
11 Educational session Geosynthetics in reinforced soil structures
2. Applications
Courtesy Huesker
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
12 Educational session Geosynthetics in reinforced soil structures
2. Applications
Slope stabilization in Trento Italy
Courtesy Huesker
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
13 Educational session Geosynthetics in reinforced soil structures
2. Applications
Reinforcement of base course
Foundation cushion
Railway and roadworks
Embankments
Bridge abutment Steep slopes
Applications of ground reinforcement
Pile foundation Bridging of sinkholes
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
14 Educational session Geosynthetics in reinforced soil structures
2. Applications
Bridge abutment
Bridge abutment at Ullerslev, Denmark, 1991 Maybe the first geogrid reinforced bridge abutment in Europe
Courtesy Huesker
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
15 Educational session Geosynthetics in reinforced soil structures
2. Applications
First permanent bridge abutment in Germany with geogrid reinforced
earth and gabion-facing Ilse bridge, 2000
Courtesy IBH Herold
geogrids
gabion 80/15
0
non w oven fabric for separation
f illing of reinforced area 0/45
Huesker Fortrac
140/30-30 MP
Huesker Fortrac
140/30-30 MP
Geogrid reinforced construction w ith gabion
facing
support construction precast
concrete girder
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
16 Educational session Geosynthetics in reinforced soil structures
2. Applications
Reinforcement of base course
Foundation cushion
Railway and roadworks
Embankments
Bridge abutment Steep slopes
Applications of ground reinforcement
Pile foundation Bridging of sinkholes
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
17 Educational session Geosynthetics in reinforced soil structures
2. Applications
Courtesy Tensar
Stabilization of a site road with geogrids combined with a nonwoven
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
18 Educational session Geosynthetics in reinforced soil structures
2. Applications
Stabilization of a site road with geogrids in combination with a nonwoven fabric
unreinforced reinforced
Courtesy Bräu
Courtesy Bräu
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
19 Educational session Geosynthetics in reinforced soil structures
2. Applications Courtesy Huesker
Courtesy Huesker
Courtesy Naue Courtesy Naue
Use of geogrids and geotextiles over soft soil under the base course
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
20 Educational session Geosynthetics in reinforced soil structures
2. Applications
Reinforcement of base course
Foundation cushion
Railway and roadworks
Embankments
Bridge abutment Steep slopes
Applications of ground reinforcement
Pile foundation Bridging of sinkholes
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
21 Educational session Geosynthetics in reinforced soil structures
2. Applications
Embankment on cemented stone colums in soft soil
Paulinenaue: German Rail 2003 cross section with two geogrid layers
Courtesy Huesker
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
22 Educational session Geosynthetics in reinforced soil structures
2. Applications
Selby Bypass, UK, 2002 Mixed solution Geogrids FORTRAC M (PVA) & FORTRAC (PET)
Courtesy Huesker
Courtesy Huesker
Embankment on reinforced concrete piles in soft soil
Courtesy Huesker
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
23 Educational session Geosynthetics in reinforced soil structures
2. Applications
Geosynthetic encased sand-columns
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
24 Educational session Geosynthetics in reinforced soil structures
2. Applications
courtesy Möbius
courtesy Möbius
Manufacture of geosynthetic encased
sand-columns
courtesy Möbius
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
25 Educational session Geosynthetics in reinforced soil structures
2. Applications
Foundation of an embankment on geosynthetic encased sand columns – land reclamation Deutsche Airbus, Mühlenberger Loch
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
26 Educational session Geosynthetics in reinforced soil structures
2. Applications
October 2001, courtesy Airbus Deutschland GmbH
Land reclamation – Airbus Mühlenberger Loch
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
27 Educational session Geosynthetics in reinforced soil structures
2. Applications
Reinforcement of base course
Foundation cushion
Railway and roadworks
Embankments
Bridge abutment Steep slopes
Applications of ground reinforcement
Pile foundation Bridging of sinkholes
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
28 Educational session Geosynthetics in reinforced soil structures
2. Applications
Collapse sink phenomena
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
29 Educational session Geosynthetics in reinforced soil structures
2. Applications
Highway A 143, Germany, 2004, Fortrac R 1200/100-10 AM
Courtesy Huesker
Bridging of sinkholes with high-strength geogrids
Courtesy Huesker
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
30 Educational session Geosynthetics in reinforced soil structures
2. Applications
Coverage of tailings-pond
tailings - pond
ringdyke geogrid coverage
Courtesy Naue Courtesy Naue
Courtesy Naue
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
31 Educational session Geosynthetics in reinforced soil structures
3. Interaction
Field test at a temporarliy abutment highway A8 (Germany)
(Bräu a. Floss, 2000)
measured: h >> 1,4
h = 1,4 calculated: Stability analysis (global)
Enlargement of bearing capacity
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
32 Educational session Geosynthetics in reinforced soil structures
3. Interaction
Jablonec nad Nisou - Střelnice
Extensometr No.1
0,00%
0,10%
0,20%
0,30%
0,40%
0,50%
1 100 10000
Days (log scale)
Str
ain
(%
)
2,0
4,0
7,0
10,0
=0,4% 2m over GL
4m over GL
10m over GL
3 years
Strain - measurement with extensometers in different layers (Herle 2006)
Enlargement of Jablonec-Střelnice Stadium
Reduction of deformations
courtesy Herle
courtesy Herle
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
33 Educational session Geosynthetics in reinforced soil structures
3. Interaction
M = 4 Ql
l/2 l/2
crack reinforcement bar
Q theoretical stress distribution detail
M
complete bond
Load transfer in a reinforced concrete beam
P
T
real load transfer
bending moments
-
+
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
34 Educational session Geosynthetics in reinforced soil structures
3. Interaction
3
Z
2
1
3 2 = 3
1 2
3
1 soil metal 1
3
2
deviatoric plane
limit state surface
O
P D
1 = 2 = 3
Principal stress state
1 = 2 = 3
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
35 Educational session Geosynthetics in reinforced soil structures
3. Interaction
1 = 2 = 3
D
3
deviatoric plane
Z
2
1
2 = 3
limit state surface
m
1
2·3
1 = 2 = 3
possible stress-states
not possible
not possible
Principal stress state
3 2 = 3
1
isotropic path: high stresses, low deformation
deviatoric path: approaching limit state, high deformation
O
P
favourable
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
36 Educational session Geosynthetics in reinforced soil structures
3. Interaction
Large triaxial compression test apparatus (Ø 500mm)
3 (vacuum)
hydraulic plunger
D = 0,5m
DU
elastic cover
base course 0/45
geogrids
measuring band
loading plate
H ≈ 1,1m
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
37 Educational session Geosynthetics in reinforced soil structures
3. Interaction
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
38 Educational session Geosynthetics in reinforced soil structures
3. Interaction
unreinforced
Geogrids
reinforced
σ1,unreinf. = σ1,reinf.
εunreinf. >> εreinf.
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
39 Educational session Geosynthetics in reinforced soil structures
3. Interaction
Radial Strains
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
40 Educational session Geosynthetics in reinforced soil structures
3. Interaction
Radial Strains
Confining Effect of the Reinforcement
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
41 Educational session Geosynthetics in reinforced soil structures
3. Interaction
Interlocking effect
increasing lateral pressure with increasing load without remarkable deformations
Courtesy Huesker
Courtesy Naue
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
42 Educational session Geosynthetics in reinforced soil structures
3. Interaction
courtesy Naue
The effect of interlocking mechanism
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
43 Educational session Geosynthetics in reinforced soil structures
3. Interaction
σ3 σ3
σ1
σ1
Stress path for unreinforced triaxial testing (CD)
σ3 = σc
σ1
[kN/m²]
σ3
[kN/m²]
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
44 Educational session Geosynthetics in reinforced soil structures
3. Interaction
Freinf. Freinf.
∆σ3 ∆σ3
σ3 σ3
σ1
σ1 new failure point
Δσ3
σ1
[kN/m²]
σ3
[kN/m²]
Δσ1
Δσ1
Activation of the
Reinforcement
∆σ3: Additional
Confining Effect
∆σ1: Increase of the Load
Bearing Capacity
Δσ1
σ3
Stress path for reinforced triaxial testing (CD)
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
45 Educational session Geosynthetics in reinforced soil structures
3. Interaction
3 1
= · tan
3+D3 1+D1
failure point without reinforcement
failure point with reinforcement
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
46 Educational session Geosynthetics in reinforced soil structures
3. Interaction
0,12m
0,2m Tragschicht
0,8m
1,0m
“Weichschicht”
Tragschicht
“Weichschicht”
0,12m
2 x 0,1m
Geogitter
0,8m
1,0m
Test Set-Up for the comparison of a unreinforced and a reinforced bearing layer
Load Bearing Layer
“Soft Soil“
Load Bearing Layer
“Soft Soil“
Geogrid
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
47 Educational session Geosynthetics in reinforced soil structures
3. Interaction
Better Load Distribution leads to less loading of subsoil
unreinforced reinforced
soft soil soft soil
bearing layer bearing layer geogrid
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
48 Educational session Geosynthetics in reinforced soil structures
3. Interaction
0
20
40
60
80
100
120
0 100 200 300 400 500 600Fu
nd
ame
nts
etz
un
g [m
m]
Fundamentlast [kN/m²]
unbewehrt
bewehrt
270 kPa
Footing Stress [kPa] Fo
otin
g Se
ttlem
ent
[mm
]
unreinforced
reinforced Ds
Different settlements for unreinforced and reinforced subgrade at the same load
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
49 Educational session Geosynthetics in reinforced soil structures
3. Interaction
v h
Q
v
v=h
h0
1
h=K0∙v
h=Ka∙v
v0
h
Stress paths under a runnning wheel
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
50 Educational session Geosynthetics in reinforced soil structures
3. Interaction
Q
v
unreinforced subgrade
h
Dh1 Dv
v
v=h
h0
1
h=K0∙v
h=Ka∙v
v0
vQ
h
2
hQ
Stress paths under a runnning wheel
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
51 Educational session Geosynthetics in reinforced soil structures
3. Interaction
Q
v
unreinforced subgrade reinforced subgrade
h
Dh1 Dv
h v
geogrid
v
v=h
h0
1
h=K0∙v
h=Ka∙v
v0
vQ
h
2
hQ
h0
v0
h
1
Stress paths under a runnning wheel
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
52 Educational session Geosynthetics in reinforced soil structures
3. Interaction
Q
v
unreinforced subgrade reinforced subgrade
h
Dh1 Dv
h v
geogrid
v
v=h
h0
1
h=K0∙v
h=Ka∙v
v0
vQ
h
2
hQ
h0
v0
h
1
Q
Dh2 > Dh1
Dv
vQ
hQ
2
Stress paths under a runnning wheel
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
53 Educational session Geosynthetics in reinforced soil structures
3. Interaction
Test Set-Up
σ1= 50kPa
Development and distribution of the earth pressure on the wall facing
Kinematic behaviour of soil grains
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
54 Educational session Geosynthetics in reinforced soil structures
3. Interaction
-1/3 Ea
No extra deformation required for geogrid activation!
Development of earth pressure
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
55 Educational session Geosynthetics in reinforced soil structures
3. Interaction
Digital Image Correlation (DIC)
from: Tropea et al. (2008)
Particle displacements Particle rotations
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
56 Educational session Geosynthetics in reinforced soil structures
3. Interaction
Sliding Planes
0
rot.
Geogrids: unreinforced
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
57 Educational session Geosynthetics in reinforced soil structures
3. Interaction
less soil moving
increasing reinforcement
less earth pressure!
unreinforced
2 Geogrids
5 Geogrids
Sliding Planes
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
58 Educational session Geosynthetics in reinforced soil structures
3. Interaction
DIC-results (detail section)
max
0
horizontal displacements
no displacment
max. displacement
(geogrid not connected to facing)
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
59 Educational session Geosynthetics in reinforced soil structures
3. Interaction
Corresponding kinematic model
(failure plane of unreinforced soil)
unconfined soil
Zone of major failure planes
Detail section Geogrids
Primary sliding body
Secundary sliding body
Geotechnical Engineering Univ.-Prof. Dr.-Ing. M. Ziegler
60 Educational session Geosynthetics in reinforced soil structures
from: www.depechemode.de
“road blocks“
Illustration of the “reinforcing effect“
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
61 Educational session Geosynthetics in reinforced soil structures
4. Summary and Conclusions
Summary and conclusions
- Ground reinforcement (with geosynthetics) is an effective way to increase the bearing capacity of different geotechnical constructions
- Under equal load the deformations of a reinforced construction are much less than the ones of an unreinforced one
-The increase in bearing capacity and the decrease in deformations can be explained by the change of the high deviatoric stress state in the unreinforced case to a more isotropic one in the reinforced state.
- This change is caused by the interlocking effect of the geogrid which enables the increase of an equivalent confining stress without remarkable deformations.
Geotechnik im Bauwesen Geotechnical Engineering Univ.- Prof. Dr.-Ing. Martin Ziegler
62 Educational session Geosynthetics in reinforced soil structures
Tests in Kyushu, Japan
Thank you for your attention
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