This dissertation analyzes implementation of a binocular tunnel underneath a historic building at low cover using ground freezing for tunnel pre-support and building underpinning. The shallow depth required tunneling through a large number of timber piles arranged in groups that serve as foundations for the steel frame, brick and masonry building. Tunneling was carried out using a sequenced excavation with shotcrete for tunnel support, commonly referred to as the New Austrian Tunneling Method (NATM). During the tunneling the building remained operational for its mainly commercial purpose. The analysis focuses on the performance of the building foundations, frozen soil and tunnel opening. Observations from the construction-monitoring program are utilized in the development of a numerical model to study the performance of the support system consisting of timber piles, frozen soil and tunnel lining.
Author:- Gall, Vojtech