Media Kit SIVA Shipping SIVA Shipping Corporate Presentation May 2012
Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states...
-
Upload
june-booker -
Category
Documents
-
view
218 -
download
1
Transcript of Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states...
![Page 1: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/1.jpg)
Lateral Earth PressuresLateral Earth Pressures
Duration: 18 min
![Page 2: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/2.jpg)
SIVASIVA Copyright©2001Copyright©2001
2
Contents
• Geotechnical applications• K0, active & passive states
• Rankine’s earth pressure theory
• Design of retaining walls• A Mini Quiz
A 2-minute breakA 2-minute break
![Page 3: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/3.jpg)
SIVASIVA Copyright©2001Copyright©2001
3
Lateral Support
In geotechnical engineering, it is often necessary to prevent lateral soil movements.
Cantilever retaining wall
Braced excavation Anchored sheet pile
Tie rod
Sheet pile
Anchor
![Page 4: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/4.jpg)
SIVASIVA Copyright©2001Copyright©2001
4
Lateral Support
We have to estimate the lateral soil pressures acting on these structures, to be able to design them.
Gravity Retaining wall
Soil nailingReinforced earth wall
![Page 5: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/5.jpg)
SIVASIVA Copyright©2001Copyright©2001
5
Soil Nailing
![Page 6: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/6.jpg)
SIVASIVA Copyright©2001Copyright©2001
6
Sheet Pile
Sheet piles marked for driving
![Page 7: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/7.jpg)
SIVASIVA Copyright©2001Copyright©2001
7
Sheet Pile
Sheet pile wall
![Page 8: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/8.jpg)
SIVASIVA Copyright©2001Copyright©2001
8
Sheet Pile
During installation Sheet pile wall
![Page 9: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/9.jpg)
SIVASIVA Copyright©2001Copyright©2001
9
Lateral Support
Reinforced earth walls are increasingly becoming popular.
geosynthetics
![Page 10: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/10.jpg)
SIVASIVA Copyright©2001Copyright©2001
10
Lateral Support
Crib walls have been used in Queensland.
Interlocking stretchers
and headers
filled with soil
Good drainage & allow plant growth.
Looks good.
![Page 11: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/11.jpg)
SIVASIVA Copyright©2001Copyright©2001
11
Earth Pressure at Rest
GL
In a homogeneous natural soil deposit,
Xh’
v’
the ratio h’/v’ is a constant known as coefficient of earth pressure at rest (K0).
Importantly, at K0 state, there are no lateral strains.
![Page 12: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/12.jpg)
SIVASIVA Copyright©2001Copyright©2001
12
Estimating K0
For normally consolidated clays and granular soils,
K0 = 1 – sin ’
For overconsolidated clays,
K0,overconsolidated = K0,normally consolidated OCR0.5
From elastic analysis,
10K
Poisson’s ratio
![Page 13: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/13.jpg)
SIVASIVA Copyright©2001Copyright©2001
13
Active/Passive Earth Pressures- in granular soils
smooth wall
Wall moves away from soil
Wall moves towards soil
A
B
Let’s look at the soil elements A and B during the wall movement.
![Page 14: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/14.jpg)
SIVASIVA Copyright©2001Copyright©2001
14
Active Earth Pressure- in granular soils
A
v’
h’z
As the wall moves away from the soil,
Initially, there is no lateral movement.
v’ = z
h’ = K0 v’ = K0 z
v’ remains the same; and
h’ decreases till failure occurs.
Active stateActive state
![Page 15: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/15.jpg)
SIVASIVA Copyright©2001Copyright©2001
15
Active Earth Pressure- in granular soils
failure envelope
v’
decreasing h’
Initially (K0 state)
Failure (Active state)
As the wall moves away from the soil,
active earth pressure
![Page 16: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/16.jpg)
SIVASIVA Copyright©2001Copyright©2001
16
Active Earth Pressure- in granular soils
v’[h’]active
failure envelope
']'[ vAactiveh K
)2/45(tansin1
sin1 2
AK
Rankine’s coefficient of active earth pressure
WJM Rankine(1820-1872)
![Page 17: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/17.jpg)
SIVASIVA Copyright©2001Copyright©2001
17
Active Earth Pressure- in granular soils
v’[h’]active
failure envelope
A
v’
h’45 + /2
90+
Failure plane is at 45 + /2 to horizontal
![Page 18: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/18.jpg)
SIVASIVA Copyright©2001Copyright©2001
18
Active Earth Pressure- in granular soils
A
v’
h’z
As the wall moves away from the soil,
h’ decreases till failure occurs.
wall movement
h’
Active state
K0 state
![Page 19: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/19.jpg)
SIVASIVA Copyright©2001Copyright©2001
19
Active Earth Pressure- in cohesive soils
Follow the same steps as for granular soils. Only difference is that c 0.
AvAactiveh KcK 2']'[
Everything else the same as for granular soils.
![Page 20: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/20.jpg)
SIVASIVA Copyright©2001Copyright©2001
20
Passive Earth Pressure- in granular soils
B
v’
h’
Initially, soil is in K0 state.
As the wall moves towards the soil,
v’ remains the same, and
h’ increases till failure occurs.
Passive state
![Page 21: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/21.jpg)
SIVASIVA Copyright©2001Copyright©2001
21
Passive Earth Pressure- in granular soils
failure envelope
v’
Initially (K0 state)
Failure (Active state)
As the wall moves towards the soil,
increasing h’
passive earth pressure
![Page 22: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/22.jpg)
SIVASIVA Copyright©2001Copyright©2001
22
Passive Earth Pressure- in granular soils
v’ [h’]passive
failure envelope
']'[ vPpassiveh K
)2/45(tansin1
sin1 2
PK
Rankine’s coefficient of passive earth pressure
![Page 23: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/23.jpg)
SIVASIVA Copyright©2001Copyright©2001
23
Passive Earth Pressure- in granular soils
v’ [h’]passive
failure envelope
A
v’
h’
90+
Failure plane is at 45 - /2 to horizontal
45 - /2
![Page 24: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/24.jpg)
SIVASIVA Copyright©2001Copyright©2001
24
Passive Earth Pressure- in granular soils
B
v’
h’
As the wall moves towards the soil,
h’ increases till failure occurs.
wall movement
h’
K0 state
Passive state
![Page 25: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/25.jpg)
SIVASIVA Copyright©2001Copyright©2001
25
Passive Earth Pressure- in cohesive soils
Follow the same steps as for granular soils. Only difference is that c 0.
PvPpassiveh KcK 2']'[
Everything else the same as for granular soils.
![Page 26: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/26.jpg)
SIVASIVA Copyright©2001Copyright©2001
26
Earth Pressure Distribution- in granular soils
[h’]passive
[h’]active
H
h
KAHKPh
PA=0.5 KAH2
PP=0.5 KPh2
PA and PP are the resultant active and passive thrusts on
the wall
![Page 27: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/27.jpg)
Wall movement (not to scale)
h’
Passive state
Active stateK0 state
![Page 28: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/28.jpg)
SIVASIVA Copyright©2001Copyright©2001
28
Rankine’s Earth Pressure Theory
Assumes smooth wall
Applicable only on vertical walls
PvPpassiveh KcK 2']'[
AvAactiveh KcK 2']'[
![Page 29: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/29.jpg)
SIVASIVA Copyright©2001Copyright©2001
29
Retaining Walls - Applications
Road
Train
![Page 30: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/30.jpg)
SIVASIVA Copyright©2001Copyright©2001
30
Retaining Walls - Applications
highway
![Page 31: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/31.jpg)
SIVASIVA Copyright©2001Copyright©2001
31
Retaining Walls - Applications
basement wall
High-rise building
![Page 32: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/32.jpg)
SIVASIVA Copyright©2001Copyright©2001
32
Gravity Retaining Walls
cobbles
cement mortarplain concrete or stone masonry
They rely on their self weight to support the backfillThey rely on their self weight to support the backfill
![Page 33: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/33.jpg)
SIVASIVA Copyright©2001Copyright©2001
33
Cantilever Retaining Walls
They act like vertical cantilever, fixed to the ground
They act like vertical cantilever, fixed to the ground
Reinforced; smaller section
than gravity walls
![Page 34: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/34.jpg)
SIVASIVA Copyright©2001Copyright©2001
34
Design of Retaining Wall
11
2 2
3 3
toe
toe
Wi = weight of block i
xi = horizontal distance of centroid of block i from toe
Block no.
- in granular soils
Analyse the stability of this rigid body with vertical walls (Rankine theory valid)
![Page 35: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/35.jpg)
11
2 2
3 3
PA
PA
PP
PPS
Stoe
toeR
Ryy
Safety against sliding along the base
tan }.{
A
iPsliding P
WPF
H
h
soil-concrete friction angle 0.5 – 0.7
to be greater than 1.5
to be greater than 1.5
PP= 0.5 KPh2PP= 0.5 KPh2 PA= 0.5 KAH2PA= 0.5 KAH2
![Page 36: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/36.jpg)
11
2 2
3 3
PA
PA
PP
PPS
Stoe
toeR
Ryy
Safety against overturning about toe
H/3
}{3/
A
iiPgoverturnin P
xWhPF
H
h
to be greater than 2.0
to be greater than 2.0
![Page 37: Duration: 18 min SIVA Copyright©2001 2 Geotechnical applications K 0, active & passive states Rankine’s earth pressure theory Design of retaining walls.](https://reader036.fdocuments.net/reader036/viewer/2022062322/5697bfb81a28abf838c9f32f/html5/thumbnails/37.jpg)
SIVASIVA Copyright©2001Copyright©2001
37
Points to Ponder
How does the key help in improving the stability against sliding?
Shouldn’t we design retaining walls to resist at-rest (than active) earth pressures since the thrust on the wall is greater in K0 state (K0 > KA)?