Frozen collar protects tunnel drive beneath rail tracks : Semprich, S; Losch, M Tunn TunnlgV22, N4, April 1990, P27–29

Abstract

Details of construction efforts undertaken to build a 184m long bypasss under the railway and south of the city of Mannheim to relieve ttaffic congstion are given. Ground freezing was chosen between cut-and-cover sections due to waterbearing ground along the path. Freezing was accomplished using 90m-long boreholes drilled parallel to the tunnel's axis to a high degree of alignment accuracy.