Ground freezing was selected to provide ground stabilization and water cut-off for the 2nd Avenue Subway expansion project. The use of ground freezing permitted safe mining operations with the TBM.Read More
The South Tail Tunnel of the No. 7 Subway Line in NYC recently required ground freezing and permeation grouting to provide ground stabilization and groundwater cutoff.Read More
This paper discusses the construction approach to using ground freezing for the first time to freeze a substantial length of tunnel for TBM mining. Techniques including the complex drilling program, aluminum refrigeration pipes, and instrumentation are discussed.Read More
Ground Freezing for Tunnel Support
No. 7 Line Subway Extension
New York City
Joseph A. Sopko, Ph.D., P.E.
Michele R. Norman