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8/17/2019 Ch 2 Earth Pressure
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EARTH
PRESSURE
Prepared By :Megha Desai
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Contents…..
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Introduction Types of lateral earth pressureRankine’s theory for active earthpressure
Rankine’s theory for passive earthpressureCoulomb’s theory for active earthpressureCoulomb’s theory for passive earthpressure
Types & design considerations for
retaining walls
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Earth pressure & retainingstructures
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• Retaining structureswhen su!cient space isnot available for mass ofsoil to spread and form
a safe slope" a structureis re#uired to retain thesoil or to keep the soil atdi$erent level.
•
%oil engineering givesthe theories of earthpressure on retainingstructure.
Megha Desai, Civil dept., CSPIT,Changa
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Introduct ion
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Introduct ion
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Retaining structure ) to retain soil ) to bear soil
pressure
The pressure e*erted by soil on retaining structure is
called +ateral ,arth -ressure.
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Introduct ion
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To estimate the correct crosssection
of retaining structure" we have to
calculate the magnitude and direction
of lateral earth pressure.
Backfll :- /The soil retained by anyretaining structure is called back0ll1.
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Introduct ion
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-roper designing of retaining walls"
cantilever sheet pile walls" braces cuts
and other similar structures re#uires
proper estimation of +ateral ,arth
-ressure.
These all are the types of retainingstructures.
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Retaining Wall
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Cantilever Sheet Pile
Wall
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Braced Cuts
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Introduct ion
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The lateral earth pressure is function of2
Type & amount of wall movement ) i.e.
towards or away from the soil.
%hear parameters of soil ) i.e. C & Ø.
'nit weight of the soil.
3rainage condition at the back0ll ) in
cohesive soil drainage is poor & vise
versa" & lateral earth pressure is
di$erent in both cohesive & noncohesive
soils.
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Typ es o Wal l! o v e " e n t s
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! The wall have tendency to move" upon
the action of lateral earth pressure of
soil. %o based on that there may be
three di$erent conditions of wall
movement2
4all cannot move i.e. at rest condition
4all move away from soil
4all move towards soil
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Type s o #a te ra l Ea r thP r e s s u r e
! 5ased on the wall
movements" upon the
action of lateral earth
pressure of soil" there are
basic three di$erent types
of lateral earth pressure2
6t rest earth pressure"
6ctive earth pressure" and
-assive earth pressure.
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t R e s t E a r t h P r e s s u r e
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AT REST EARTH PRESSURE $% 4hen the soil mass is not
sub7ected to any movement or lateral yielding called at
rest earth pressure.
4all is restrained
from moving i.e. at
rest condition.
8h ) -ressure
e*erted by soil" on
retaining wall.
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c t i v e E a r t h P r e s s u r e
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ere the wall moves away from the
soil at the amount 9ΔH’.
6ssuming the failure wedge :as shown
in 0g.;" & wall may tilt away from the
soil retained backside of wall" it is the
active condition.
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c t i v e E a r t h P r e s s u r e
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ACTIE EARTH PRESSURE $% 6ctive earth pressure is
occur when the soil mass yields in such a way that it tends
to stretch hori
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P a s s i v e E a r t h P r e s s u r e
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The wall is moving towards the soil at
the amount 9ΔH’.
6ssuming the failure wedge :as shown
in 0g.;" & wall may be pushed in tothe soil retained backside of wall" it is
the passive condition.
ere with su!cient wall movement"
soil wedge will fail" which is called as
passive condition.
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P a s s i v e E a r t h P r e s s u r e
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PASSIE EARTH PRESSURE $% 6 state of passive
pressure e*ists when the movement of wall is such that
the soil tends to compress hori
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L a t e r a l E a r t h P r e s s u r e
a t R e s t
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Considering any soil element at depth
9=’ from the e*isting ground surface.
>n this element. 3ue to overburden of
soil above vertical stress 98v’ will act in
vertical direction" and hori
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L a t e r a l E a r t h P r e s s u r e
a t R e s t
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,C, Ø
>4 T> 6?6+@%, TI% 98h’AAAAA
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Reerences'(
Books:• 6rora" B.R." %oil echanics & (oundation ,ngineering
• -unamia" 5.C." %oil echanics & (oundation ,ngineering
• urthy" D.?.%." %oil echanics & (oundation ,ngineering
• Denkatramaiah" C." Eeotechnical ,ngineering
Internet:• httpFFwww.engr.uconn.eduFGlanboFC,HJ+ect4KK%lopestabi
lityK.pdf
• elearning.vtu.ac.inFKJFenotesFJLCDLF'nitL%D3.pdf
• http://nptel.ac.in/courses/105108075/module8/Lecture30.pdf
23
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• httpFFpeople.eng.unimelb.edu.auFstsyFgeomechanicsMte*tFChKKM%lope.pdf
• httpFFstep.ipgp.frFimagesFeFeNFJOMJKM+imitMe#uilibriumMslopeMstability.pdf
• httpFFcivilwares.free.frFEeotechnicalPHJengineeringPHJPHJ-rinciplesPHJandPHJ-racticesPHJofPHJ%oilsPHJechanicsPHJandPHJ(oundationPHJ,ngineeringFChapterPHJKJ.pdf
• httpFFsite.iuga
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http://site.iugaza.edu.ps/wp-content/uploads/Lesson%2006-Chapter%206%20Slope%20Stability.pdfhttp://site.iugaza.edu.ps/wp-content/uploads/Lesson%2006-Chapter%206%20Slope%20Stability.pdfhttp://civilwares.free.fr/Geotechnical%20engineering%20-%20Principles%20and%20Practices%20of%20Soils%20Mechanics%20and%20Foundation%20Engineering/Chapter%2010.pdfhttp://civilwares.free.fr/Geotechnical%20engineering%20-%20Principles%20and%20Practices%20of%20Soils%20Mechanics%20and%20Foundation%20Engineering/Chapter%2010.pdfhttp://civilwares.free.fr/Geotechnical%20engineering%20-%20Principles%20and%20Practices%20of%20Soils%20Mechanics%20and%20Foundation%20Engineering/Chapter%2010.pdfhttp://step.ipgp.fr/images/e/e7/05_01_Limit_equilibrium_slope_stability.pdfhttp://step.ipgp.fr/images/e/e7/05_01_Limit_equilibrium_slope_stability.pdfhttp://people.eng.unimelb.edu.au/stsy/geomechanics_text/Ch11_Slope.pdfhttp://people.eng.unimelb.edu.au/stsy/geomechanics_text/Ch11_Slope.pdf