Tan Shunhui, Chairman - CREG
The past few years have witnessed the rapid development of the tunneling industry in Asia. To further improve the construction quality of tunnels, advanced TBM methods are being adopted in more and more tunnel projects.
In China, the full-face horseshoe-shaped TBM (width 11.9m× height 10.95m) supplied by CREG was used in the tunnel of Mengxi-Huazhong Coal Transportation Railway (The West Inner Mongolia-Central China Railway) for the first time. The best monthly rate of the machine was 308m, which is a lot faster than the traditional mining method. The project was awarded the “ITA Technical Project Innovation of the Year 2018”.
Compared with the traditional circular TBM, the excavated volume of the horseshoe-shaped TBM was reduced by 10 - 15%, which saved the overall construction cost of projects. CREG has overcome key challenges including once-through shaping, complex position and attitude control, design of the horseshoe-shaped segment, and segment erection plan in variable curvature.
This project extends the TBM technology to the field of horseshoe-shaped section tunneling. Its successful development is of great significance in terms of liberating labor from highway and railway tunnels with poor conditions in mountains, and the deep overburden double-track metro tunnel with high costs, besides improving construction safety and lowering production costs.
In Singapore, the 7.62m × 5.645m rectangular TBM, an innovative equipment of CREG, was successfully applied to Thomson Line T221, which was awarded Project of the Year Award (SPMI PoY) 2016-2017 under the Engineering & Construction Category.
This project marks the first trial of Singapore in using the Rectangular TBM in metro construction. The project features shallow overburden (5.5-6m) and the underground water level is 0.8-1.4m. Though the total drive is only 150m, the hydrogeology is complex. The first 90m mainly consists of miscellaneous fill, muddy clay and other strata. It is difficult to maintain pressure and the bearing capacity if the foundation is low. The last 60m is mainly completely weathered granite stratum, and there are boulders in some parts. Thus, the construction was difficult.
Technical breakthroughs have been achieved in aspects such as multi cutter head collaborative driving with low disturbance in rectangular section, double screw conveyors collaborative discharging, and thin rectangular shield skin. Rectangular shield can successfully deal with shallow overburden, presence of underground pipelines and other obstacles. It has a wide range of applications - in addition to the entrance and exit of the subway, it can also be applied in the construction of urban underpass, common utility tunnel, underground shopping mall, underground parking, and other projects.
Currently, CREG has secured nearly 1,000 TBM orders. Its products and services have been exported to Malaysia, Singapore, Vietnam, India, Israel, Lebanon, Qatar and the UAE.
CREG focuses on reasonable utilization of underground space development and increase of effective supplies, especially in the field of underground utility tunnel, expressways, garages, warehouses, logistics, and urban sewage pipelines.
Currently, CREG has secured nearly 1,000 TBM orders. The products and services of CREG have been exported to many Asian countries/regions including Malaysia, Singapore, Vietnam, India, Israel, Lebanon, Qatar and UAE. By virtue of the advanced construction experiences and construction methods gained from these experiences, CREG can provide comprehensive solutions for the development of underground spaces.
NBM&CW December 2019
