Northwest ChinaConstruction / Shotcrete

Air for secondary-lining shotcrete in a highway tunnel in western China

Background

Tunnel shotcrete uses a lot of air at modest pressure — a classic low-pressure, high-flow duty. Many contractors only have high-pressure units and run them throttled, paying high-pressure fuel bills for low-pressure work.

Solution

They switched to a DMT tunnel unit in a low-pressure, high-flow configuration (45 m³/min @ 7 bar), matching pressure to the job, with the variable-speed drive following the spraying rhythm.

Results

Energy per cubic metre dropped markedly; spraying pressure is steadier and rebound improved.

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