Study On Safety Estimation Of Expressway Tunnel

A lot of facts prove that kinds of tunnel disease would appear during the usage due to different factors, and the disease will inevitably reduce tunnel bearing capacity and reliability during the usage.The paper adopts field test method and numerical simulation method to analyze the reliability of secondary lining during the construction and long term usage of the tunnel.During the tunnel construction period, rock mass and the lining is monitored by setting kinds of apparatus in the tunnel, and the safety index of the tunnel during the construction is educed on the base of the measure datum.The mechanics state of secondary lining is simulated under different conditions of the rock mass, buried depth and effective thickness, and the reliability index of the tunnel during these conditions is educed.The mechanics state of secondary lining is simulated under the condition of a hole of different range existing in the top the arch, and the reliability index of the tunnel during these conditions is educed.The mechanics state of secondary lining is simulated under the condition of a piece of crack existing in the top the arch, and the reliability index of the tunnel during these conditions is educed.By analyzing the mechanics state of secondary lining under different tunnel diseases, several treatments is put forward in the paper.Based on the field test and numerical simulation, the advice value of the design thickness and the limit effective thickness of secondary lining is brought forward in the part of conclusion of the paper.