The Malaysia East Coast Railway is a landmark project under the Belt and Road Initiative, symbolizing the joint construction efforts between China and Malaysia. As the largest international construction project undertaken by China, the railway spans 688 kilometers, adhering to China’s first-class standards for passenger and freight electrified railways. The design speed is 160 km/h for passenger transport and 80 km/h for freight transport.
A critical component of this project is the Yunding Tunnel, which belongs to the eighth section of the Malaysia East Coast Railway and serves as a key control project. Located in the northeast mountainous area of Kuala Lumpur, the tunnel crosses the Bajaran Mountains with a total length of 16.389 kilometers, making it the longest tunnel in Southeast Asia upon completion.
The tunnel adopts a “double tunnel parallel” construction plan, where two single-track tunnels are excavated simultaneously using Tunnel Boring Machines (TBMs). Excavation begins from shallow buried sections at the left and right tunnel entrances and proceeds toward the tunnel’s central starting point. For sections not accessible to the TBM, the drilling and blasting method is applied until they connect seamlessly. The inverted arch section uses prefabricated installation processes, while the arch walls are constructed synchronously with 16-meter synchronous lining trolleys.
Our company is responsible for assembling, dismantling, excavating, and synchronously lining the TBM equipment for both tunnels. During peak construction periods, we deployed over 400 management, technical, and operational personnel.
The Yunding Tunnel Project marks our second major international TBM project following the NJ project in Pakistan. Its successful implementation highlights the expansion of our TBM expertise from the hydraulic tunnel industry into the railway tunnel construction sector.
The NJ Hydropower Station, located in the Muzaffarabad region of Kashmir, is a key priority project within the energy sector of the China-Pakistan Economic Corridor. The station has a total installed capacity of 969 megawatts, producing 5.15 billion kilowatt-hours annually. This accounts for 12% of Pakistan’s hydropower generation, significantly addressing the region’s power shortage.
The NJ hydropower station TBM project marks the company’s first overseas TBM project. The 2nd TBM diversion tunnel stretches 11.2 kilometers, with a diameter of 8.53 meters and a depth of approximately 1,900 meters. The excavation was carried out in a reverse slope manner, presenting significant engineering challenges.
The project area features complex geological conditions, requiring the TBM to traverse unfavorable fault zones. During construction, the team faced difficulties such as strong rock bursts, mudstone softening in water, large convergence deformation in high burial-depth sections, and ground heat exceeding 35°C. Despite these challenges, the TBM equipment was successfully assembled on June 6, 2012, and the tunnel was completed on October 18, 2016.
The successful execution of this project highlights the company’s capability to overcome challenging geological environments, marking a milestone in its international TBM operations.
Liaoning Dahuofang Water Conveyance Project is the first TBM project undertaken by the company, which is the world's longest hydraulic tunnel under construction at that time. The total length of the construction section of our company is 22.65km. The diameter of TBM excavation is 8.0m, and the excavation is along the slope. The TBM test excavation began on July 19, 2005 and was completed on April 12, 2009. The average monthly footage of TBM was 618m, which created the highest construction records in China, such as the daily footage of TBM excavation with the same diameter at that time was 40.8m and the monthly footage was 1058.1m. In the process of construction, problems such as clamping machine, large deformation of surrounding rock and large water gushing are encountered.
The maximum buried depth of No. 3 diversion tunnel of Jinping secondary hydropower station is about 2525m, the total length of the tunnel is 16.67km, and the excavation diameter of TBM is 12.4m. It is the tunnel with the largest diameter constructed by using hard rock TBM in China with the characteristics of large buried depth, long tunnel line and large diameter. The work started in August 2007, and the water supply was realized in March 2014. During the working process, there are some difficult problems, such as rock burst and water gushing.
