High-Grade Concrete for the Single Permanent Shotcrete Lining Method

With the single permanent shotcrete lining method in underground construction in rock, a shotcrete layer placed subsequently to the application of the supporting shotcrete replaces the cast in-situ inner lining. As a general rule, this layer is placed on the supporting shotcrete after the deformations have faded. Because of the firm bond of the shotcrete layers, their interaction in the sense of a bonded construction is ensured. The excavation section and the concrete consumption are reduced. Formwork is no longer required. With the composition of the shotcrete and the placing technique employed in former tests, it was difficult to fully incorporate any necessary reinforcement and to produce dense high-grade shotcrete.