On March 20, according to the official social media account of China Railway Construction Corporation Limited (CRCC), the No. 3 drainage tunnel of the Hainan Nuclear Power Plant, constructed with the participation of CRCC's Eighth Bureau, has been successfully connected.
This project marks the completion of the first land-based drainage tunnel and the first tunnel construction in China to utilize a sea dike structure to receive the shield machine.
The drainage project for units 3 and 4 of the Changjiang Nuclear Power Plant in Hainan includes a shield machine launching shaft, a drainage tunnel, and a sea transformation shaft, using the "one machine, one hole" shield method. The recently completed tunnel is the right-line tunnel, with a total length of approximately 1,800 meters.
Long-Distance Underwater Tunneling Construction
To ensure the safety of long-distance underwater tunneling construction, the project team actively carried out technical research, resulting in 12 domestic utility model patents, 5 international patents, and 1 QC achievement. During this period, the project team collaborated with relevant units to develop a novel shield tunnel wedge-shaped roller cutter, which significantly increased tool life and excavation mileage. It solved the construction problem of pressurized opening and tool replacement in underwater fracture zones, laying the foundation for tunnel completion.
Shield Machine Arrival Section Construction
Before the shield machine exits the tunnel, it is necessary to complete the grouting reinforcement of the end face, readjust the attitude of the shield machine, seal the tunnel portal, and install the receiving base. Simultaneously, it is necessary to strengthen the pulling connection of the pipe segments in the exit section and perform secondary grouting and waterproofing inside the tunnel.
To this end, the project team planned in advance, deployed resources, and implemented additional safety measures for exiting the tunnel, such as emergency airbags and short sleeves with double-layer long tail brushes. They simulated the construction process of the arrival section, comprehensively analyzed construction risks, and formulated reliable preventive measures.
Through meticulous organization, promoting orderly connections between various procedures, and implementing measures such as special inspections with the owner, supervisor, and other units before the shield machine leaves the tunnel, the project team has effectively ensured the safe and controllable receipt of the shield machine. Subsequently, China Railway No. 8 Bureau's Hainan Nuclear Power Project team will ensure the safe and smooth completion of Tunnel No. 4, and earnestly complete the subsequent construction tasks to complete the drainage work of Hainan Nuclear Power Units 3 and 4 on schedule.
