About Ground Freezing

Mass ground freezing to facilitate jacking of three massive tunnels beneath active Amtrak lines serving South Street Station for Boston’s Big Dig

Under certain circumstances, it may be desirable to freeze massive volumes of soil to facilitate excavation within the frozen stabilized ground. These types of freezes are less common than peripheral freezes.

Mass freezing may be justified where:

  • Ground control in difficult subsurface conditions is crucial to the success of a project.
  • No geologic cut-off is present within reasonable depth below subgrade at a proposed location. In this case, the use of ground freezing may necessitate a mass freeze, artificially creating the bottom seal that local geology failed to provide.
  • There is concern about the overall safety of the operation.