Abstract:

The geological information of the tunnel face on Hubei Section of ZhengzhouWanzhou Highspeed Railway is collected and analyzed based on large mechanized construction characteristics; and then the tunnel face stability is divided into four grades, i.e. Grade A (whole stable), Grade B (partial rockfalling), Grade C (partial unstable) and Grade D (whole unstable); finally, a classification method for tunnel face stability is established based on three indices of rock hardness, rock integrity and groundwater status, and the relationships between the stability grades and the surrounding rock grades are obtained. The study results show that: (1) The three indices, rock hardness, rock integrity and groundwater status are with the highest utilization rate. (2) The stability of Grade Ⅰ, Ⅱ and Ⅲ surrounding rock belongs to Grade A.

Key words: large crosssectional tunnel on ZhengzhouWanzhou Highspeed Railway, tunnel face stability classification, rock hardness, rock integrity, groundwater status, advanced support