Abstract:

In this paper, the concept and effect of pilotheading method are presented, and the characteristics and applicable conditions of pilotheading method are analyzed. The construction schedules of 3 tunnels located in different geological conditions are simulated in terms of excavation and primary support, and comparison and contrast is made between simulated construction schedules and actual/designed construction schedules. Conclusions drawn are as follows: 1) TBM pilotheading method is not suitable for singletube tunnels located in soft, weak and fractured strata; 2) Instead of other construction galleries, TBM pilotheading method may be adopted for singletube tunnels. 3) Twin TBM pilotheading method is suitable for twintube extralong tunnels, which has advantages in terms of construction schedule, cost and coping with unfavorable geological conditions; 4) TBM pilotheading method is suitable for the construction of tunnels in Sichuan and Chongqing area. Finally, the application of TBM pilotheading method is prospected.

Key words: tunnel, TBM pilotheading, enlarging method, drilling and blasting method