China’s Largest TBM - With Panda Face Emerges From Tunnel

On 12 December 2022 ‘Jinxiu’ - China’s largest EPB TBM developed by CRCHI - marked the first smooth breakthrough of the Jinxiu Tunnel, a key control project of the Chengdu-Zigong high-speed railway.


Jinxiu is China’s largest diameter EPB TBM with completely independent intellectual property rights. It has a 12.79m diameter and weighs 3,000 tons. It is 135m long and has 7500kW installed power. Its cutterhead coating has very Sichuan characteristics; a giant panda holding tender bamboo occupies central position.

Located in Jinjiang District, Chengdu, the Jinxiu Tunnel goes down one km south from the starting point (Chengdu East Railway Station) and goes up to the ground only after the South Third Ring Road, with a total length of 3,655 meters, of which the underground tunnel is 2,620 meters long.

The geological cover along the tunnel is shallow at only 8 to 60 meters to the ground. The project passes under prosperous areas such as Chengdu’s southeast central ring road, with many high-rise buildings on the ground, dense municipal tracks, and complex pipelines, making construction difficult and risky.

In order to cope with the project’s complex geology and surrounding environment, the R&D team of CRCHI carried out a tailored design of the Jinxiu TBM and solved several construction problems. For example, by optimizing the tool design, only two cutters were changed during the total 1937 meter advance in the composite strata which had strong weathered mudstone and weak, weathered mudstone. Zero risk was realized when the TBM passed under the existing Chengdu East Ring Right Line and the Chengdu-Guiyang high-speed railway (the existing railways are all ballasted tracks). CRCHI’s hard rock TBM marks great achievement in the San Gawang Hydropower Station Project in Peru by cutting and progressing at over 1000 m/month

On 6 December 2020, when the first hard rock TBM was exported to South America by CRCHI, it recorded an advance rate of more than 1000 meters per month in the construction of the San Gawang Hydropower Project in Peru.

The San Gawang Hydropower Station is a representative project of the ‘Belt and Road’ Initiative in South America and the first power project invested by Chinese enterprises in Peru. The total installed capacity of the San Gawang Hydropower Station is 209.3 MW, and the designed annual power generation is 1.25 billion kWh. After its completion and operation, it will optimize the allocation of regional water resources, leading to more sustainable economic and social development in South America.


The TBM is about 245m long and the cutterhead diameter is 5.83m. It is particularly suitable for tunneling in the geological conditions of San Gawang Hydropower Station. The surrounding rock of the tunnel has high stability, and the strength of the rock stratum is medium-high.

During the TBM’s assembly and commissioning, the on-site service team of CRCHI closely cooperated with the owner and the constructor. In less than 40 days, the TBM’s main body assembly and its horizontal push into the tunnel were completed, and the split launching was realized. After the TBM was powered on, it took only two weeks to complete the single machine commissioning, joint commissioning and etc., realizing the formal launching.

Since November 2022, the single shift advance rate of the TBM has kept breaking new records by advancing at a rate of 10m per shift to 16m and 20m per shift. The maximum single shift advance rate exceeded 26m and the maximum daily advance rate reached 46m. The cumulative advance rate in November reached 1007.9 meters, which has greatly shortened the construction period.