Development Of Risk Assessment And Early Warning System For Tunnel Diseases During Operation Period

At present,the construction of all kinds of underground engineering structures is in a period of rapid development.However,due to the extremely complex environmental conditions of underground engineering and the limited monitoring indicators,a large number of tunnel lining structures are facing the interference of various diseases during the operation period,which affects the operation safety and service life of the tunnel.Once the tunnel accident occurs,it will cause a lot of loss of people’s lives and property.Therefore,it is of great significance to establish a reliable risk assessment and early warning system for tunnel diseases during the operation period and accurately evaluate the safety of tunnel lining structure during the operation period.In this paper,through case statistics,numerical simulation,theoretical analysis and program development,the risk assessment and early warning of tunnel diseases in operation period are realized.The main achievements are as follows(1)This paper makes a detailed statistics on the typical cases of tunnel lining structure diseases in recent years in China,analyzes the types of diseases that affect the safety of tunnel lining structure in operation period,and according to the actual cases of different diseases,improves the disaster classification standards of corresponding disease indexes,so as to provide reference for the disaster risk assessment of tunnel diseases in operation period The model provides the basis for the research.(2)According to the displacement and deformation data of tunnel lining structure,the risk assessment model of tunnel deformation disaster based on grey correlation analysis method and entropy weight method is established.Based on the modified usage and finite element calculation,the relationship between bending moment,axial force,displacement and bending stiffness efficiency of tunnel lining structure is analyzed.According to the current failure criteria of tunnel lining structure,the risk classification criteria of tunnel deformation disaster risk assessment model are obtained.Finally,taking the tunnel lining displacement and deformation data as the evaluation data,the risk level of tunnel deformation is evaluated and applied to the actual engineering case to verify the feasibility and effectiveness of the model.(3)Aiming at the situation that the displacement and deformation data of tunnel lining structure are incomplete or difficult to measure,a Bayesian network analysis and evaluation model is established.Based on confrontation network and analytic hierarchy process,the problem of training sample imbalance is solved,and the model database is enriched.EM algorithm is used for data training and learning to improve the accuracy of model prediction.Finally,according to the four-color criterion,combined with the failure degree and failure probability,the comprehensive risk analysis of the current structural state of the tunnel is carried out,and applied to a specific engineering case to prove the reliability of the model.(4)Based on the above two risk assessment models of tunnel diseases in operation period,the risk assessment and early warning procedures of tunnel diseases in operation period are developed to form a comprehensive system based on "data processing risk assessment safety diagnosis measure suggestion".Through the construction of tunnel disease case database during the operation period,data support is provided for the selection of reasonable project disposal scheme,and the application efficiency of risk assessment and early warning model is improved.This paper has 62 pictures,36 tables and 115 references.