History of Retaining Walls and Wall Failures

History of Retaining Walls

It is believed that Retaining walls originated from ancient Egypt. The walls were designed and constructed to hold back the Nile river. The used the walls to keep the river from flooding and eroding the soil. This wall was a gabion style wall made from reeds and it would divert the river to into the reservoirs and into the fields for farming purchases.

Failures of Retaining Walls

Under static conditions, the retaining walls are acted on by body forces that relate to the mass of the wall, the soil pressures and any other external forces that are present. A retaining wall that is design properly will achieve equilibrium of these forces without inducing shear pressure that approaches the shear pressure of the soil. However, during an earthquake, inertial forces and changes in the soils strength might violate equilibrium and as a result it might deform the retaining wall. When the deformation becomes too excessive, sliding, tilting, bending or other mechanism can occur.

Gravity Walls

• This wall typically fails due to sliding or/and overturning occur
• Sliding occurs when the horizontal pressures are not at equilibrium. When the lateral pressures are greater than the resistance force that the wall can provide from the base.
• Overturning occurs when moment(torque) equilibrium is not being satisfied
• The wall can slope down because of the instability of soil that is behind and beneath the wall  

Cantilever Walls

• They are also subjected to the same failures of gravity retaining walls. They are also subjected to flexural failure mechanism:
• Flexural failure is when the wall ruptures, fractures, and/or bends
• This depends on the geometry, stiffness, and strength of the wall.
• To stabilize the soil, bending moments occur but if the bending exceeds flexural strength of the wall, flexural failures will occur

References 

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