Liquefaction Prevention
Most airports' potential problem is liquefiable fill, typically on bay mud. Ports and harbors are also often built on artificial fill, which amplifies earthquake shaking. Ports consist of bulk storage facilities and warehouses, cranes to move large containers, and rail and other facilities that connect the port to the land-side transportation system. Liquefaction can cause large areas to sink below the water surface. Rails can buckle, become misaligned, and rotate. Pavement surfaces also buckle, often in ways similar to roadways and airport runways.
Liquefaction prevention is a remedial measure for existing structures where other remedial measures cannot be implemented. A perimeter soil-cement cutoff wall is recommended to isolate cohesionless soils under the existing structure. The groundwater within the perimeter cutoff wall is then permanently lowered to provide a dry or non-liquefiable zone under the structure. Reinforcement of liquefiable soils is accomplished by installing soil-cement walls in block, wall, or grid patterns to resist the stress from embankments or other structures when loose cohesionless foundation soil liquefies during seismic ground shaking.
Project Example:
Port of Oakland