“Forepoling” system – in tunnel construction

Diorit offers a wide range of forepoling systems, also known as canopy tubes or tube umbrella systems.These solutions are designed to install canopy tubes in weak ground conditions using either top-hammer jumbos or DTH drill rigs.

Umbrella systems be installed using steel casings between 12 and 18 metres in length, interconnected using Diorit -designed threads that allow for fast, easy connections – saving you time and money. Diorit’s forepoling casing systems inject grout through the casing, thanks to an arrangement of staggered grouting valves in the casing itself. This allows for secondary support to be formed, increasing safety and stability in the working area before further excavation the tunnel, which is an essential requirement when drilling in sensitive ground conditions or overburden. Forepoling bits and ring and also the pipe system are designed for the construction and drilling of tunnels in conditions of weak ground. Rings and bits are designed for mounting on both surface and deep hydraulic hammers. Rings and bits can be delivered with or without the pipes.

The system is available from 76 to 219 mm, and for all main bit supports and threads on surface and deep hydraulic hammers. Pipe threads are available at 2-3 by 2-3 initial trapezoidal threads and 10 mm inlet. Different availability of threads enables accelerated installation of the pipe on-site system.

• Very high-quality integration of ring case and bit
• The ring housing is welded to the starter tube in production and is supplied as such
• The ring controls the guidance and operation of the bit
• Option – installation of valves in production (3-10 bar)

Catalog Diorit Piperoof/Forepoling system