Abstract：From the view of mechanics, tunnel excavation is a kind of load. The movement of working face can be seen as the process of load moving. Learn from the concept of influence line in structural mechanics, the Influence Line of Excavation (ILE) in tunnel engineering is defined as relationship curve between the index and the position of working face. Comparing with influence line of freely supported beam, the main characters of ILE in tunnel engineering are non-linear, limited range and the maximum response not being gotten when working face arriving the monitoring section. The ILE based on the background engineering indicates the crown settlement caused by excavation of Drift 6 is maximum, about occupying 21.5% of the total settlement. The excavation volume of drift 9, 10, 11 is about 40% of the total volume, but due to the protection of final lining, the crown settlement caused by these three drifts is only 2.1% of the total settlement. From the shapes of ILEs, it can be seen that most of the settlement of Point A is happened 5m ahead and 15m after working face. Moreover, when the working face arrived monitoring section, the settlement would have the greatest increase.
