EARTH RETAINING STRUCTURES

These structures shape and hold soil in a manner unnatural to that material. Since soil is a semi-fluid material, when shaped in a manner contrary to its nature, it moves, slides, and flows in an attempt to reach equilibrium. A properly functioning retaining structure provides the equalizing force to resist the forces and movement of the earth as it attempts to reach equilibrium.

Earth retaining structures fail when the forces exerted by the earth exceed the capacity of the structure or when the structure deteriorates and can no longer resist the earth forces.

The retaining wall system consists of the installed structure, the mass of earth being retained, and the surrounding mass of earth affected by the system. Consequently, the following issues concerning their failure become critical:

• How did the system fail?
• What caused the failure?
• Was a proper system selected to retain the soil?
• Did the system change since the retaining wall’s construction?
• Could this situation have been foreseen and prevented?