China’s Largest‑home‑developed Tunnel‑boring Machine Rolls off Assembly Line in Zhengzhou

According to China Railway Group Limited, the super‑large‑diameter slurry balance tunnel‑boring machine, named CREC‑1662, has been completed in Zhengzhou, Henan Province. Developed jointly by three subsidiaries under China Railway, it ranks as the largest tunnel‑boring machine independently developed within China. 

The cutting diameter measures 16.68 metres, with a total machine length of 125 metres and an overall weight of roughly 4,800 tonnes.

The new tunnelling equipment is scheduled for deployment on the tunnel section of Hefei G4001 Link Road which runs underneath Dongpu Reservoir. This tunnel stretch extends for approximately 2.9 kilometres and adopts a twin‑tube, double‑deck layout. 

It represents one of the rare domestic projects where a super‑large‑diameter tunnel‑boring machine passes beneath a major reservoir functioning for both flood‑control and municipal water‑supply purposes. Complex site conditions impose exacting standards on tunnelling precision and attitude adjustment for the whole machine.

CREC‑1662 is fitted with an atmospheric cutter‑head that allows tool replacement under normal atmospheric conditions even when the working environment sustains pressure up to 8 bar. This design supports efficient tunnelling while safeguarding on‑site personnel. 

A circulating muck‑removal system has also been integrated. The machine applies an advanced slurry‑treatment solution combining direct discharge via screw conveyors with external crushing. 

This configuration maintains high‑efficiency slag evacuation through slurry pumps and removes operational hazards linked to personnel entering the chamber to service crushing units, reinforcing safety for sub‑aqueous tunnel construction.