Ground Improvement Methods & Design

There are various treatment techniques that are available to improve the condition of poor or unstable ground by altering the nature of the soil insitu. For example, where loose sands or man- made fill are encountered, deep densification methods can be used to increase the density of the material to a degree that allows for construction of shallow foundations or, in the case of loose sands, mitigates potential for liquefaction during a seismic event. Otherwise, costly over-excavation of the unsuitable material or deep foundations may be required. GZA engineers have extensive experience with the design and construction of several types of ground improvement techniques, and are aware of their appropriate applications and limitations.

GZA looks at each project and each site independently and regularly develops economical alternatives to conventional foundation systems. Ground improvement is a method which has been successfully implemented by GZA on several projects, often times as value engineering alternates, thus saving the Contractor time and money. Examples of applications include dynamic compaction of loose silty sands to improve stability and mitigate liquification; chemical grouting for groundwater control during soft ground tunneling; soil mixing to increase wall stability for future dredging operations; and jet grouting to facilitate jacking of an historic structure that settled. The various techniques that may be employed include:

  •     Jet Grouting
  •     Chemical and Permeation Grouting
  •     Compaction Grouting
  •     Soil Mixing
  •     Deep Densification (vibro compaction, deep dynamic compaction)
  •     Stone Columns
  •     Blast-induced Compactions
  •     Preloading/Surcharging
  •     Geosynthetics and Soil Reinforcement
  •     Cement/Lime Stabilization

Project applications include embankments for highways and rail, bridges, buildings, tunnels, underpinning of structures, site development, dams and waterfront structures.