Liquefaction of cohesionless soils can be caused by strong vibratory motion due to earthquakes. Research and historical data indicate that loose granular soils and non-plastic silts that are located below a relatively shallow groundwater table are more susceptible to liquefaction. Ninyo & Moore has experience with a wide variety of projects where liquefiable soil was a concern. To evaluate such soils, they are typically explored and sampled with exploratory borings and/or with cone penetrometer test soundings, and analyzed with stateof-the-art numerical tools and software.

Mitigation measures for liquefiable soils can include various techniques, including:

• Deep pile foundations
• Ground modifications, including:
  • Stone columns
  • Deep dynamic compaction
  • Compaction grouting
  • Remedial grading