ASSALAMUALAIKUM & GOOD MORNING DON’T EVER HURT OTHER PEOPLE’S FEELING.

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