ABSTRACT
In order to extend the scope of application of mechanised tunnelling with single-shell segment lining in solid rock, an annular gap fill material has been developed, which is capable of being pumped and acting as a drainage layer, with a kF value > 10–4 m/s. The particular relationships of construction material, process technology and construction were completely taken into account. The basic idea is the defined foaming of cement suspension with a foam generator, which produces an open-pored and permeable structure with sufficient strength to ensure the bedding of the segments. The general suitability of the method has been impressively demonstrated in the course of an extended test programme including site trials.
