On July 5th, the Changsha Xiangya Road river-crossing tunnel opened to traffic. The tunnel is the largest diameter shield driven tunnel in Hunan Province, China. The opening of the tunnel will alleviate traffic on the nearby Yinpenling Bridge and Yingpan Road Tunnel, connect networks and smooth traffic flows. The tunnel was constructed by CRCHI (China Railway Construction Heavy Industry Corporation Limited) large-diameter slurry TBM “Xingsheng”. The TBM started the left line boring on March 30th, 2021 and the right line on June 20th, 2022. The twin-tunnel holed through on March 12th, 2023.
The Xiangya Road river-crossing tunnel project starts from Yuehua Road in the Yuelu District in the west and extends to Furong Road in the Kaifu District in the east. The total investment of the project is 5.33bn yuan. The project has a total length of 4,180m. The river-crossing section – constructed by the shield machine – has an approximate 1.4km length. The shield machine tunnel passed under the Xiangjiang River dike four times and crossed two riverbed fracture zones with more than 450m in length twice. It is the first two-way six-lane river-crossing tunnel in Changsha.
The “Xingsheng” slurry TBM has a maximum excavation diameter of 15.01m and an overall length of approximately 129m. The TBM adopted a heavy-duty composite cutterhead, high-wear and long-life cutting tools and a 7.6m heavy-duty main bearing design, which effectively resolved the impact issues on the cutterhead during the excavation of the riverbed rock layers and composite strata. The frequency of cutter replacement was reduced, the excavation efficiency is increased, and the smooth construction of the tunnel ensured, says CRCHI.
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