Research On Collapse Mechanism And Treatment In Jiangyuanling Tunnel

As a form of structure which across the mountains, there are more and more tunnel appear in high grade highway construction. Tunnel collapse often happened in the construction because of the characteristics of large cross-section highway tunnel excavation and the complicated geological conditions. This not only seriously affects the quality、construction period and the cost of the project but also brings the great loss to people’s life and property. If the tunnel diseases treatment is inappropriate, it not only impacts later maintenance work, but also leaves security hidden danger to the tunnel operation.This paper will take Jiangyuanling tunnel of Tong (cheng)-Ping (jiang) highway collapsed roof caving accidents as an example, it expounds the cause of the tunnel collapse comprehensively from engineering geological factors、hydrology geology factors、construction factors based on the basis of predecessors’ achievements, and explores the collapse occurring mechanism. According to the engineering geological conditions, setting up YK32+366numerical calculation models of collapse section and three dimensional collapse section using FLAC3D software. It mainly analyses the influence of groundwater seepage to tunnel collapse for YK32+366collapse section; It mainly analyses the change of the stress field、 displacement field、 supporting structure stress and plastic zone when the collapse happened for the three dimensional collapse section. The results of numerical simulation provide the basis for the analysis of collapse reason in theory; also can test the accuracy of the results at the same time. Monitor measuring results show that the collapse treatments are reasonable and effective, and the measures are feasible. It proved collapse treatment scheme is reasonable once again through the simulation computation of follow-up period of collapse using FLAC3D. Some useful conclusions can be obtained through the JiangYuanling tunnel collapse accident, this will be guidance and reference for tunnel construction, also this paper can give some reference for similar engineering accidents.