- Gravity Retaining Walls
- Semigravity Retaining Walls
- Cantilever Retaining Walls
- Counterfort Retaining Walls
- Anchored Retaining Walls
- Reinforced Retaining Walls
- Slurry Walls
- Sheet Pile Walls
- Braced Cuts
1- Function of Retaining Wall Different Types For Different Purposes.
2- Soil Properties
3- Determine the Stability of The R.W.
- Unit Weight
- Angle of Friction
- Cohesion C
4- Design The Retaining Wall Sections
- Bearing Capacity
- Overall Stability
- Check the Strength
- Steel Reinforcement or Steel Cross section
1- Function of the Retaining Wall
2- Soil Properties
3- Method of Determining Lateral Earth Pressure
4- Checking the stability of the R.W.
5- Designing Cross Section of the R.W.
1- Coulomb's Lateral Earth Pressure Theory
2- Rankine's L.E.P
3- Culmann Method ---- Graphical
4- Poncelet Method ---- Graphical
5- Limit Analysis --- Lower and Upper bound Solution
6- Numerical Methods --- FEM & BEM
Coulomb assumed friction between the wall and the soil.
Because of that friction
1- Frictionless wall (Smooth) 2- Cohesionless Soil (Sand or Gravel) 3- Vertical Wall (90o with Horizontal) 4- Horizontal Backfill Surface 5- Flexible Wall
1- Active Pressure
2- Passive Pressure
1- For low walls of fairly short length
Exposed height = 1 m to 3 m
Length = 40 m or less
2- Where the backfill zone is limited and or it is necessary to use the existing soil as backfill.
1- Stem shear and bending due to lateral earth pressure on the stem.
2- Base shear and bending moments caused by the wall loading produced earth pressure on the wall footing.
3- Overall stability
4- Stability against bearing capacity failure
- Sliding along the base
- Overturning about the toe
- Rotational stability
5- Stability against excessive base settlement resulting in a large wall tilt.
I- Sand and Gravel:For all stages of construction and after construction use:
II- Clay:For cohesive soils the first three months after the construction the soil is undrained.
Therefore, the design parameters are:
III- Silts:Silt is in between cohesive and cohesionless soil.
The design parameters in this case can be taken as obtained from the total stress tests.
That is for the analysis of the R.W. immediately after construction.
The final active earth pressure to which the wall will be subjected can be determined from an effective stress analysis using .
SOME DESIGN CONSIDERATION
1- Rain water in tension cracks
2- Critical height for R.W. in cohesive soils
3- Choice of backfill Material
4.a Design of Filter Behind Retaining Walls
* Compaction of backfill in a confined wedge behind the wall tends to increase the lateral earth pressure beyond those represented by Rankine's or Coulomb earth pressure theories.
* For guidance on lateral earth pressure computations associated with compaction of granular soil use the following methods: