Full-Scale Model Experimental Research on Concrete Construction Technology of Steel Shell Immersed Tube Tunnel

A full-scale model experiment was carried out to research the effects of the Self-Compacting Concrete (SCC) construction technologies including SCC working performances, casting speeds and the arrangement methods of vent holes on the filling quality of the steel shell immersed tube tunnel compartments. The experimental results showed that in order to guarantee the bearing capacity of structure mainly by reducing the voids as many as possible to meet the related requriements of Guide, the total area ratio of voids with the depth more than 5.0 mm in the whole top surface of compartments must be less than 5%, the initial slump flow of SCC should be improved to 670±50 mm on account of the flowability loss caused by the particle migration of coarse aggregates during pumping and at least ten vent holes distributed around the top plate of a steel shell compartment parts of which were located on the both ends of T ribs far from the pouring holes are needed, simultaneously the appropriate pouring speeds of SCC are respectively 30 m³/h and 15 m³/h when the distances from fresh concrete level to compartment roof are more and less than 20 cm.