On November 14th2024, the U-shaped “CREC 1508” TBM passed its FAT in Xinxiang city of Henan province, China, for use on the Yuen Long South Development flood control scheme in the Northern Metropolis of Hong Kong.
The U-shaped TBM is 9.36m in width and 20.72m high, and has been independently designed and manufactured by China Railway Engineering Equipment Group Co., Ltd. (CREG). Its design and manufacturing allows the use of the open cut method of constructing utility tunnels. Combining the advantages of both the open cut and TBM methods, the U-shaped TBM provides a mobile support structure post-excavation that allows the installation of the main structure of the utility tunnel inside the TBM, making it suitable for the construction of shallow prefabricated utility tunnels.
This project has a total length of 1km with a finished 6.15m (width) x 6.35m (height) box culvert cross-section. The geology consists of sandy and silty clay in high levels of groundwater, with some sections containing a large amount of silt.
CREG has innovatively integrated the TBM with the pipe erecting machine, which, the company says, can achieve an efficient and integrated construction process for utility tunnels. “This includes transportation, excavation, support, TBM tunnelling, pipe erection and side gap backfilling, which is a new technological breakthrough in the mechanized construction of prefabricated utility tunnels.
“Compared with the traditional open cut method, the U-shaped TBM method has higher mechanization, better safety performance and a faster construction speed. It requires a smaller construction area, reduces slope excavation and produces less muck and lower noise and vibration, lessening its environmental impact. These advantages make the method safer, faster, more economical, labor-saving and environmentally friendly,” adds CREG.
