Retaining wall

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Retaining wall

  1. 1. RETAINING WALL
  2. 2. Retaining wall: Retaining walls are structure used to retain soil, rock or other materials in a vertical condition. Hence they provide a lateral support to vertical slopes of soil that would otherwise collapse into a more natural shape. Most common materials used for retaining walls are: - Wood sheets; - Steel and plastic interlocking sheets; - Reinforced concrete sheets; - Precast concrete elements (crib walls and block walls); - Closely spaced in-situ soil-cement piles; -- Wire-mesh boxes (gabions); - Anchors into the soil or rock mass (soil nailing).
  3. 3. EARTH RETAINING STRUCTURE Earth retaining structure can be classified to 2 types: A) Externally Stabilized Systems i) In- Situ Walls ii) Gravity Walls B) Internally Stabilized Systems i) Reinforced Soils ii) In-Site Reinforcement
  4. 4. FUNCTION To retain the soil at a slope that is greater than it would naturally assume, usually at a vertical or near vertical position.
  5. 5. 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.
  6. 6. 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
  7. 7. 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.
  8. 8. 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.
  9. 9. 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.
  10. 10. GRAVITY WALL There are many types of gravity wall such as the followings: a) Massive Gravity Wall b) Crib Wall c) Cantilever Gravity Wall
  11. 11. GRAVITY WALL
  12. 12. cement mortar plain concrete or stone masonry cobbles They rely on their self weight to support the backfill 12
  13. 13.  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.  Even though it need moderately skilled labor but the construction process is very labor extensive.
  14. 14. 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.
  15. 15. CRIB WALL  Another type of gravity retaining structure  It consists of precast concrete members linked together to form a crib The zone between the member is filled with compacted soil
  16. 16. CRIB WALL
  17. 17. CANTILEVER GRAVITY WALL STEM 8 IN WIDE CONCRETE BLOCKS SOIL REINFORCING STEEL 12 IN. WIDE CONCRETE BLOCK TOE Large Flexural Stresses At Base Of Stem REINFORCED CONCRETE FOOTING HEEL
  18. 18. 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 overturning  These walls require much less construction material because the cross section 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.
  19. 19. Reinforced; smaller section than gravity walls They act like vertical cantilever, fixed to the ground 19
  20. 20. COUNTERFORT WALL
  21. 21. GABION WALL
  22. 22. 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
  23. 23. 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.
  24. 24. GROUTED TIEBACK ANCHOR WALER SHEET PILE WALL SOIL • Wall With Tieback Anchors
  25. 25. SHEET PILES
  26. 26. SHEET PILE WALLS
  27. 27. SOLDIER PILE WALLS  Consist of a vertical wide flange steel members with horizontal timber lagging.  Often used as temporary retaining structures for construction excavation
  28. 28. SLURRY WALLS  It’s a cast-in-place concrete walls built using betonies slurry  The contractor digs a trench along the proposed wall alignment and keeps it open using the slurry  The reinforcing steel is inserted and the concrete is placed using pumps. As the concrete fills the trench, slurry exits at the ground surface.
  29. 29. Basha Retaining Walls - Applications Metros and Subways Road Train 31
  30. 30. Basha Retaining Walls - Applications highway 32
  31. 31. Basha Retaining Walls - Applications High-rise building basement wall 33
  32. 32. Advances in retaining wall Reinforced Retaining Walls • Sometimes the complexity or wall height required for certain installations require retaining walls that are reinforced by either geofabric material or, in really tough cases, concrete filled doubleskin layers of blocks
  33. 33. Geosynthetic Reinforced Soil Segmental Retaining Walls • Geosynthetic reinforced soil segmental retaining walls utilize reinforcing sheets of geogrid or suitable woven geotextile which are attached to the fascia and are embedded in a body of engineered fill. • The integrated nature of the fascia and the abutting large body of reinforced soil thereby supports the applied earth forces. In this case the 'gravity' component of the retaining wall is provided by the reinforced soil mass acting as a monolithic unit.

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