assalamualaikum & good morning don’t ever hurt other people’s feeling
TRANSCRIPT
ASSALAMUALAIKUM & GOOD MORNING
DON’T EVER HURT OTHER PEOPLE’S FEELING
EARTH RETAINING STRUCTURE
EARTH RETAINING STRUCTURE CAN BE
CLASSIFIED TO 2 TYPES THAT IS:
A) Externally Stablilized Systems
i) In- Situ Walls
ii) Gravity Walls
B) Internally Stabilized Systems
i) Reinforced Soils
ii) In-Site Reinforcement
RETAINING WALL
FUNCTION
To retain the soil at a slope that is greater than it would naturally assume, usually at a vertical or near verticalposition.
DESIGN
The designed retaining wall must be able to
ensure the following : Overturning doesn’t occur Sliding doesn’t occur The soil on which the wall rests mustn’t be
overloaded The material used in construction are not
overstressed.
DESIGN CONSIDERATION
In order to calculate the pressure exerted at
any point on the wall, the following must be
taken in account: height of water table nature & type of soil subsoil water movements type of wall material used in the construction of wall
The effect of 2 forms of earth pressure need to
be considered during the process of designing
the retaining wall that is:
a) Active Earth Pressure
“ It is the pressure that at all times are tending
to move or overturn the retaining wall”
a) Passive Earth Pressure
“It is reactionary pressures that will react in
the form of a resistance to movement of the wall.
ACTIVE EARTH PRESSURE
It is composed of the earth wedge being retained
together with any hydrostatic pressure caused by
the presence of groundwater.
This pressure can be reduced by:
i) The use of subsoil drainage behind the wall
ii) Inserting drainage openings called weep holes through the thickness of the stem to enable the water to drain away.
PASSIVE EARTH PRESSURE
• This pressure build up in front of the toe to resist the movement of the wall if it tries to move forward.
• This pressure can be increased by enlarging the depth of the toe or by forming a rib on the underside of the base.
GROUNDWATER BEHIND A RETAINING WALL
DEFINITION OF GROUNDWATER
Groundwater can be defined as water
which is held temporarily in the soil above
the level of water table.
EFFECT OF GROUNDWATER TO RETAINING WALL
have adverse effect to the design and stability the water behind the wall could increase the
active pressure on the back of the wall It will reduce the soil shear strength that would
lead to reduction of soil bearing capacity The water will reduce the frictional resistance
between the base and the soil and also reduce
the possible passive pressure in front of the wall
It can be concluded that the existence of
groundwater behind the retaining wall
could lead to failure of retaining wall. Therefore, ways must be found to drain the
groundwater out from behind the wall. Normally, weep hole will be installed in the
retaining wall where it will penetrate the
retaining wall and drain the area
immediately behind the wall.
Adequate spacing between the weepholes
allow uniform drainage from behind the
wall. Weep holes should have filter material
between the wall and the backfill to prevent
fines migration, weephole clogging, loss of
backfill and caving
EARTH RETAINING STRUCTURE
SPECIFICALLY ON “GRAVITY WALL”
GRAVITY WALL
There are many types of gravity wall such as
the followings:
a) Massive Gravity Wall
b) Crib Wall
c) Cantilever Gravity Wall
GRAVITY WALL
It’s construction only need simple materials
and moderately skilled labor But the required volume of material is very
large because there’s steel reinforcement is
used. Eventhough it need moderately skilled
labor but the construction process is very
labor extensive.
MASSIVE GRAVITY WALL
Often made of mortared stones, masonry or
reinforced concrete It resist the lateral forces from the backfill
by virtue of their large mass These walls are very thick, so the flexural
stresses are minimal and no reinforcement
is needed.
CRIB WALL
Another type of gravity retaining structure It consists of precast concrete members
linked together to form a cribThe zone between the member is filled with
compacted soil
CRIB WALL
CANTILEVER GRAVITY WALL
TOE
HEEL
SOIL
REINFORCED CONCRETE FOOTING
REINFORCINGSTEEL
12 IN. WIDE CONCRETE
BLOCK
8 IN WIDE CONCRETE
BLOCKS
Large Flexural Stresses At Base Of Stem
STEM
CANTILEVER GRAVITY WALL
It is a refinement of the massive gravity wall
concept These wall have much thinner stem and utilize
the weight of the backfill soil to provide most
of the resistance to sliding and overturningThese walls require much less construction
material because the crossection of this wall is
much smaller.
It have a large flexural stresses which
requires the use of reinforced concrete or
reinforced masonry It must be carefully constructed & requires
skillful labor less expensive than mass gravity walls most common type of earth retaining
structure.
COUNTERFORT WALL
GABION WALL
EARTH RETAINING STRUCTURE
SPECIFICALLY ON “IN-SITU WALL”
IN-SITU WALL
Different from gravity walls There are many types of In-Situ wall such
as the followings:
a) Sheet Pile Walls
b) Soldier Pile Walls
c) Slurry Pile Walls
SHEET PILE WALLS
Sheet piles are tine, wide steel piles Driven to the ground using pile hammer Series of sheet piles in a row form a sheet
pile wall It’s usually necessary to provide lateral
support at 1 or more levels above the
ground that can be done using 2 ways that
is internal braces or tieback anchor
Tieback Anchors are tension members
drilled into the ground behind the wall The most common type is a grouted anchor
with a steel tendon
• Wall With Tieback Anchors
SHEET PILE WALL
WALERGROUTED TIEBACKANCHOR
SOIL
SHEET PILES
SHEET PILE WALLS
SOLDIER PILE WALLS
Consist of a vertical wide flange stell
members with horizontal timber lagging.Often used as temporary retaining structures
for construction excavation
SOLDIER PILE WALL
SLURRY WALLS
It’s a cast-in-place concrete walls built using
bentonite slurry The contractor digs a trench along the proposed
wall alignment and keeps it opem using the slurry The reinforcing steel is inserted and the concrete
is placed using pumps / tremie pipe As the concrete fills the trench, slurry exits at the
ground surface.
SLURRY WALL
SLURRY WALL
SYUKRAN JAZILAN = DOMO ARIGATO GOZAIMASU
HOPEFULLY YOU UNDERSTAND THIS CHAPTER