Vertical or near-vertical slopes of soil are supported by retaining walls, cantilever sheet-pile...
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Lateral Earth Pressure and Retaining Walls
Vertical or near-vertical slopes of soil are supported by retaining walls, cantilever sheet-pile walls, bulkheads sheet-piles, braced cuts and other similar
Vertical or near-vertical slopes of soil are supported by
retaining walls, cantilever sheet-pile walls, bulkheads
sheet-piles, braced cuts and other similar structures.
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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
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Lateral Support Gravity Retaining wall Soil nailing Reinforced
earth wall
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Sheet Pile Sheet pile wall dr. isam jardaneh / foundation
engineering 61303 / 2010
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Soil Nailing dr. isam jardaneh / foundation engineering 61303 /
2010
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Lateral Support dr. isam jardaneh / foundation engineering
61303 / 2010
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The proper design of those structures requires an estimation of
lateral earth pressure. Lateral earth pressure is a function of
several factors, such as: The type and amount of wall movement The
shear strength parameters of the soil The unit weight of the soil
The drainage conditions in the backfill dr. isam jardaneh /
foundation engineering 61303 / 2010
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At Rest Active Passive
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Lateral earth pressure is a function of effective vertical
stress dr. isam jardaneh / foundation engineering 61303 / 2010
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h= f ( v)
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h=k v K=coefficient of lateral earth pressure
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dr. isam jardaneh / foundation engineering 61303 / 2010 Lateral
earth pressure is a function of effective vertical stress
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Ko = 0.19+0.233log(PI) Ko = 0.4 + 0.007 (PI) for 0 > PI >
40 Ko = 1 - sinfor NCC Ko = 0.95 - sinfor NCC Ko = 0.46 + 0.001
(PI) for 40 > PI > 80
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Wall moves away from the soil
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Rankine's theory, developed in 1857 William John Macquorn
Rankine 1820 1872 Scottish civil engineer, physicist and
mathematician.civil engineer He was a founding contributor to the
science of thermodynamics, particularly focusing on the first of
the three thermodynamic laws.thermodynamics Rankine developed a
complete theory of the steam engine and indeed of all heat
engines.steam engine He was an enthusiastic amateur singer, pianist
and cellist who composed his own humorous songs. He was born in
Edinburgh and died in Glasgow, a bachelor.EdinburghGlasgow
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Assumptions No friction between the backfill soil and retaining
wall. Angle of friction() = 0 Retaining wall is vertical Surface of
backfill is horizontal
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Rankine Active Earth Pressure
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` a = Rankine Active earth pressure ` 0 = Effective vertical
stress C = Cohesion = Angle of internal friction Ka = Rankine
active pressure coefficient Ka =(1 sin )/(1+sin) =
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Zc = depth at which pressure = zero Zc = depth of tensile
cracks
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Example
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Example
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Use this
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Example
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Charles Augustin de Coulomb Born in France. His studies
included philosophy, language and literature. He also received a
good education in mathematics, astronomy, chemistry and botany. He
was involved in structural engineering, soil mechanics, as well as
other fields of engineering. He discovered an inverse relationship
of the force between electric charges and the square of its
distance, later named after him as Coulomb's law.electric
chargesCoulomb's law Coulomb leaves a legacy as a pioneer in the
field of geotechnical engineering for his contribution to retaining
wall design. His name is one of the 72 names inscribed on the
Eiffel Tower.geotechnical engineeringretaining wall72 names
inscribed on the Eiffel Tower 1736 - 1806
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Coulomb Active Earth Pressure
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Comments: Coulomb considered friction Due to friction, the
failure surface is NOT PLANE He considered it PLANE for easy
solution No big difference in results When increases, the error in
calculating Pp increases and the situation may be UNSAFE The REAL
failure surface is LOGSPIRAL as shown
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ACTIVE PASSIVE 45 - /2 45+/2 45 - /2 Pa Pp H/3
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Example
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Wall moves towards the soil
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Rankine Passive Earth Pressure
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dr. isam jardaneh / foundation engineering 61303 / 2010 Use
this
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Passive Pressure Passive Force where
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Example Solve this problem for passive case
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Coulomb Passive Earth Pressure
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dr. isam jardaneh / foundation engineering 61303 / 2010 *
Coulomb 1776 assumes that there is friction between RW and backfill
materials * Passive means the wall moves into the backfill
soil.
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Problem # 1
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dr. isam jardaneh / foundation engineering 61303 / 2010 Problem
# 2 Refer to problem # 1 above. For the retaining wall, determine
the Rankine active force per unit length of the wall and the
location of the line of action of the resultant.
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dr. isam jardaneh / foundation engineering 61303 / 2010 Problem
# 3
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dr. isam jardaneh / foundation engineering 61303 / 2010 Problem
# 4
