Abstract:

Compared with circular tunnel, the horseshoe shaped tunnel has the advantage of high space utilization rate. Hence, the horseshoeshaped EPB shield has been applied to Baicheng Tunnel on Haolebaoji Ji′an Railway in China for the first time, which realized safe, rapid and environmentally friendly construction. Based on the shield tunneling data statistic, it is found that the average construction efficiency reached 203 m per month, the segment assembly efficiency reached 38~43 min, and great challenges were encountered when tunneling in Gingerolite geology. In this paper, the application effect of shield in 4 construction stages are introduced, and the influence of excavation blind area on composite cutterhead and thrust system, the countermeasures of the soil conditioning and the double screw conveyor system under loess geological condition in northern Shaanxi, and the advantages and disadvantages of horseshoeshaped segment erector in application are analyzed. In order to promote the widely application of horseshoeshaped shield in more and more geological fields and improve the construction efficiency, some suggestion for the future developing direction of shield that developing full crosssection profiling cutterhead and the intellectualization of segment assembly system, which can realize full area excavation, improve the efficiency of mucking system, reduce the total thrust, reduce the difficulty of personnel operation and improve the accuracy of the assembly process, is provided.

Key words: horseshoe , shaped tunnel, shield, composite cutterhead, profiling cutter, construction efficiency, segment assembling