June 7-10, 2009
The poster shows experience on construction using hiDCon-Elements (High Deformable Concrete) in several tunnels. The yieldable concrete elements for the application in squeezing rock conditions have a beam shape and are longitudinally fixed to the excavation surface at different locations. The elements are incorporated into the tunnel lining when the shotcrete is added. If the lining is subjected to a radial rock pressure of the designed value the normal force in the lining will cause the hiDCon-Elements to yield thus preventing the shotcrete from being overstressed. Application of these yieldable concrete elements in strongly swelling rock is achieved by using the new design concept called “Modular Yielding Support”, in which compressible elements of high bearing capacity are placed between the structure and the rock. On the one hand, this method permits a reduction of swelling pressure to a predetermined maximum value. On the other hand, replacement of these elements is possible at any time without impairing the flow of traffic.
Patrick Steiner, "TUNNELLING IN SQUEEZING AND SWELLING ROCK BY USING HIGH DEFORMABLE CONCRETE ELEMENTS" in "Shotcrete for Underground Support XI", Felix Amberg, M.o.S. ETHZ, SIA, Switzerland; Knut F Garshol, BASF Construction Chemicals, LLF, USA Eds, ECI Symposium Series, (2009). http://dc.engconfintl.org/shotcrete/20