1736 Profile Horse Shoe Floor installation in circular profile Method Cutting out wedges Concrete floor segments Backfill Pros • Closest to conventional profile • Smaller excavation diameter • Higher advance rates reachable • Lateral space can be used for ducts, conveyors and cable trays • Floor segment design can include drainage channel Cons • Only for very competent rock • Slows down overall advance rate • Increased excavation diameter required Figure 3 – Floor preparation Beyond geometric adaptation, the circular profile offers additional functional potential. A backfilled floor can accommodate integrated drainage pipelines or service channels within the invert. The sidewall zones above the flat floor level provide protected corridors for the installation of power, water, and data lines. Conveyor systems and electrical infrastructure installed during the development phase may, where compatible with mine planning, remain in place for later operational stages, potentially reducing reinstallation effort and associated costs. These interface solutions demonstrate that circular TBM profiles can be aligned with established mining operational standards while simultaneously offering opportunities for integrated infrastructure planning. In this context, profile adaptation becomes part of the broader system-level shift from sequential excavation toward infrastructure-integrated underground development. 4.4 Branching, Retractability, and Layout Flexibility Mining layouts frequently require bifurcations, cross-cuts, and phased development strategies. Conventional TBM systems designed for long linear infrastructure tunnels must therefore be adapted to enable repositioning and controlled retreat. Retractable TBM concepts and pre-planned junction structures allow the machine to withdraw within the completed tunnel and initiate new headings from prepared branch points. Enhanced steering systems enable tighter curve radii compared to conventional civil tunnelling standards, improving layout flexibility in confined underground environments. Such adaptations extend the applicability of TBMs beyond single access drives toward more complex mining network configurations, further reinforcing the transition from equipment-based excavation toward integrated underground system design.
RkJQdWJsaXNoZXIy MTM0Mzk2