Southwest ChinaConstruction / Tunnelling

Air supply for underground powerhouse tunnelling at a hydropower project in southwest China

Background

Tunnel air demand has a clear pattern: drilling, shotcreting and mucking alternate, so demand rises and falls. Fixed-speed units can only unload and idle at low demand while the meter keeps running, and in an enclosed cavern their noise echoes and makes the workplace even louder.

Solution

A DMT tunnel unit was used: a permanent-magnet variable-speed drive loads to the actual demand curve, with a multi-layer acoustic canopy and isolation mounts.

Results

Idle running at low demand was almost eliminated and energy use on long continuous supply dropped noticeably; tunnel noise improved, making work and communication easier.

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