State-of-the-art report — engineering practice in artificial ground freezing

In the present paper an attempt has been made to summarize the current state-of-theart of engineering practice in artifical ground freezing. The paper shows the tremendous increase in knowledge and diversified applications in ground freezing over the past ten years and, together with other papers ih the Symposium, provides a useful background against which practicing engineers may. gain an understanding of ground freezing. As discussed in this paper, there are gain an understanding of ground freezing. As discussed in this paper, there are However, it is the author's assessment that the current state of knowledge is sufficient for safe designs and that future refinements in the area of structural analysis will only lead to more accurate deformation predictions and to possibly thinnerdesign frozen sections. Since the sizes of frozen sections are often more a function of construction practicality rather than design requirements, it is questionable whether potentially thinner sections will have a significant impact on actual construction.

An area that promises to have tremendous impact on the competitive nature of freezing for soft-ground tunneling is in improved horizontal drilling techniques. Several contractors are currently developing drilling equipment for horizontal drilling over large distances, whereas today the maximum economical distance is in the range of 30–40 m.