Wall Failures

Table of Contents

Failures of Retaining Walls

Under static conditions, the retaining walls are acted on by body forces that relates 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.

• Sliding or Overturning

  • 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  

Sliding                               Overturning                                        Slope Down

Open

• Flexural Failure

  • Flexural failure mechanism is when:

    • The wall ruptures, fractures, and/or bends

    • This depends on the geometry, stiffness, and strength of the wall

    • Poor drainage can lead to flexural failure

  • To stabilize the soil, bending moments occur but if the bending exceeds flexural strength of the wall, flexural failures will occur

A Rupture of the Retaining Wall

Open

Cases of Retaining Wall Failures

Castle Village Before the Collapse	Castle Village After the Collapse
Open

• Nicole Highway Evacuation

  • This highway is located in Singapore and the highway collapsed on April 20th, 2004

  • The highway collapsed because the retaining wall for the transit tunnel underneath the highway had collapsed

  • The retaining wall had collapsed because the soil simulation had overestimated the strength of the soil at the site and had underestimated the forces that are acting on the retaining wall

  • After this incident, any evacuations that were constructed in Singapore had extra robustness were added in order to prevent another collapse from happening

Before the Collapse of the Wall	After the Wall Collapsed
Open	Open

References 

Contributors: