| The rapid development and evolution of urban rail transit operation tunnel diseases pose a direct threat to the tunnel structure health.Therefore,it is necessary to carry out research on diseases identification and structural health status evaluation of urban rail transit operation tunnels.Trough extensive reference to domestic and foreign literature,statistical analysis,numerical simulation and numerical calculation of on-site special testing data,this paper focuses on the characteristics and identification methods of diseases in urban rail transit operation tunnels,the evolution mechanism of tunnel structure health deterioration considering the cavity and structural cracks behind the lining,the comprehensive evaluation method of tunnel structure health state and the control strategy of tunnel structure health,etc.The main work and research achievements are as follows:（1）Based on the analysis of relevant research results and field investigation,the main disease types of urban rail transit operation tunnel are put forward,including three categories,including the defect behind the lining,the apparent quality of the structure and the damage of the concrete structure,and nine subcategories.In each subcategory,there are three kinds of subdivided diseases,totally 9 subcategories.Based on the field special inspection data of tunnel diseases in 11 interval tunnels of multiple subway lines in a city,the 9 subdivision diseases of urban rail transit operation tunnels proposed in this paper are analyzed according to the characteristic parameters of the diseases,such as size,area,location,type and damage causing,this lays a foundation for the establishment of the evaluation index system for the health status of urban rail transit tunnel structure in the following paper.（2）Considering from the perspective of the whole life cycle of the tunnel,this paper summarizes the main influencing factors of urban rail transit operaton tunnel diseases,including the interference from complex operation environment,tunnel structure maintenance is not timely and tunnel construction quality is not up to standard during the construction period,and carries out a detailed analysis.In addition,considering the difference of tunnel disease characteristics,three tunnel disease identification methods based on physical scale,test parameters and GPR image interpretation are proposed and described in detail.（3）A three-dimensional solid numerical simulation model of tunnel structure was established to study the effects of specific disease on the health deterioration of tunnel structure.The failure state,Z-displacement and the maximum principal stress of the tunnel lining are analyzed under the condition of structural cracks and cavities behind the lining.Considering the two kinds of specific structural cracks and voids in the tunnel finite element model,aiming at the assumption that the diseases appear in different parts of the tunnel lining structure and the diseases of different sizes in the tunnel,a total of 16 working conditions were designed and the finite element analysis was done.Through comparative analysis,it is concluded that the changes of physical scale such as the location,length and depth of specific disease will have an impact on the deterioration of tunnel structure.（4）A comprehensive evaluation method for the structural health status of urban rail transit tunnel is put forward.Based on the four-level classification,a multi-level evaluation index system was established,which took the structural health status evaluation of operating tunnel as the objective layer,7 subdivided diseases as the intermediate factor layer,and 14 disease attribute indexes as the index factor layer.Considering the mutual influence among evaluation indexes,the 0-1 variable xi j is introduced to construct the influence correlation judgment matrix.Combined with the importance weight vector obtained by 1G method,the comprehensive weight vector is defined.The membership degree of evaluation index is calculated by constructing the normal distribution membership function.The evaluation grade of structure health status is determined by multi-level fuzzy comprehensive decision.An evaluation calculation model based on multilevel fuzzy comprehensive decision making is established.（5）The above comprehensive evaluation model has been successfully applied to the tunnel between station A and station B of A metro line in A city.The evaluation results show that the comprehensive evaluation grades of the structural health state of the three detection sections in the tunnel mining section are"Grade I","Grade I"and"Grade II"respectively,and the comprehensive evaluation grades of the structural health state of the two detection sections in the shield tunneling section are"Grade II"and"Grade I"respectively.According to the acceptance criterion of structural deterioration of urban rail transit operation tunnel proposed in this paper,the countermeasures are given. |
PDF Full Text Request