Reliability Analyze & Its Assessment Of Expressway Existing Tunnel Structure

With the development of the tunnel construction, especially many expressway tunnels, more and more attention has been paid to the reliability and security of the tunnel structure which is in active service. However, the traditional safety evaluation method involves only single safety factor and fails to consider the random characteristic of the impact parameter, the method has many insuperable defects. So the study of the theory and the method of the structure in service will be not only fit for the practice tunnel construction but also helpful for the further revision of the structure designing criteria and the reliability judging standard.This paper, on the basis of much reference, summarizes the structure reliability judging model, analyses the existing merit and default, and establishes the structure stability under the influence of outer environment, time and interior impact for improving the defect of the past study of the structure reliability judging model which is restricted by the single factor.This paper discusses the influencing factor and instability form of the tunnel structure, summarizes the crack type of the tunnel lining, describes the judgment of the tunnel stability and establishes the stability of judgment and the reliability factor of the speedway tunnel.Among the tunnels in service, due to so many effect factors, the geology situation in site and the tunnel itself should be considered in the same time. On the foundation of the practical geology, the structure and the practical observation data, the study takes speedway tunnel in service into account, by virtue of thinking integration and technology, make the tunnel and the rock mass in the same environment and firstly sets up the speedway tunnel health consultation decision making system. It begins with the practical data, by means of many subsystems to realize the quantifying of health consultation and pathology prediction. With the help of the man-computer technique and visualization technology, this system can make the real-time visualization evaluation.In the aspect of the practice engineering, corporated with the Dayu tunnel in the Dandong to Benxi speedway in LiaoNing province, the element and practical data have been collected first, and then by using the system the Dayu tunnel has been evaluated simply, which we believe provides new methods helping the tunnel engineering repair and stabilization. This paper makes much useful discussion about the reliability theory of the speedway tunnel in service, which has great theory and practical value in the sides of making best use of the tunnel structure potency, optimizing maintenance decision and structural stabilization mechanism.