ABSTRACT
The ITM principle distinguishes itself by the ECL production technology without reinforcement, combined with continuous progress.
The quality of a tunnel lining produced by an ECL process depends on the performance of the concrete injection system. Injection of the concrete in the annular space formed by the formwork on the inside and the surrounding soil on the outside, should continuously match the TBM progress and the local soil and groundwater pressures. This requires a flow-controllable positive displacement pump combined with pressure control in the TBM concrete injection ring.
The formwork construction is vital in the ITM process, fulfilling two main functions. First the formwork supports the extruded concrete tunnel lining until it is fully self-supporting. At the same time the thrustforce of the TBM is transferred via the formwork to the extruded concrete tunnel lining.
In a conventional TBM drilling and ring erection is carried out consecutively, without any necessarily connection between these two processes. In contrast to this stepwise operation the ITM extrusion process performs optimal in combination with a continuous shield advance. Furthermore the concrete has to be mixed and the required formwork has to be erected and dismantled. All these processes have to be synchronised for a successful operation. To be able to automate these processes an extensive study has been carried out which resulted in realistic models, including the dynamic relations between them.
The developed models form a simulator, which replaces the real process. Thus this simulator is not only a test-tool for the automation but also for training the operators.
