CRCHI Mega Slurry TBM "Jinghua" Assists the First TunnelS ection Breakthrough of Beijing East Sixth Ring Road Reconstruction Project

In September 2022, the Beijing East Sixth Ring Road Reconstruction Project reported another good news. The CRCHI mega slurry TBM "Jinghua" smoothly reached the intermediate air shaft, marking the project have achieved staged victory.

The maximum excavation diameter of the slurry TBM "Jinghua" is 16.07 m, the length of the whole machine is 150 meters, and the total weight is 4300 tons. “Jinghua”, which is the largest shield machine in China, adopts a series of targeted optimal design and system integration, such as the fourth-generation accessible cutter exchange technology, telescopic main drive, extreme high pressure auto-compensation, large power slurry circulation system, and synchronous double-liquid grouting. The successful application of synchronous double-liquid grouting technology has realized the millimeter-level control of ground settlement, ensured zero disturbance to existing buildings on the ground during TBM construction, and filled the gap of synchronous double-liquid grouting in mega slurry TBM construction in China.

The tunnel length is 7,338 meters. Its complex geology is mainly composed of sandy soil, water-rich and high-density sand, interactive layers of silt and cohesive soil. The project also face the construction difficulties such as super-deep soil cover, and super-sensitive environment.

The slurry TBM has successfully excavated 4,772 meters and reached the intermediate air shaft after 16 months since its initial excavation. The slurry TBM has successively overcome technical difficulties such as the initial excavation with shallow overburden and long-distance crossing high-density sand layers. The slurry TBM continuously crossed the Beijing-Harbin Railway and Beijing sub-center comprehensive transportation hub with micro-settlement and non-disturbance. It created 542 meters excavation record in a single month.

It is reported that the Slurry TBM "Jinghua" will carry out a second excavation after finishing TBM inspection and maintenance in the intermediate air shaft, and will continue to excavate 2.6 kilometers forward to reach the receiving well in Wansheng South Street. At that time the tunnel excavation work will be completed.