Study On Construction Risk Early-warning In Mountain Areas Large-section Highway Tunnel

With the national economic development, the number of mountain tunnels increase faster and faster, In order to meet the growing requirement of traffic flow or transportation, large-cross section,the form of large-span tunnels, in particular, an increasing number of 3,4 lane mountain highway tunnel. As the tunnel cross-section increases, resulting in an increase of the difficulty in construction, making the tunnel construction security accidents occur frequently. In a series of tragic incidents, we can see that: In the current construction conditions, for large-section tunnel construction, there is no clear awareness of risk management, What a bitter price caused without clearing Consciousness of risk management and the concept of early-warning of risk management, Therefore, study on mountain regions large-section of highway tunnel early-warning system is in imminence, it is not only the objective needs of the tunnel security management, but also the assurance of the actual needs of achievement of objectives.In this paper, according to the immature status of mountain regions large-section of highway tunnel construction risk management, theory of risk management and early-warning theory applied to the actual tunnel construction, proposing the establishment of mountain regions large-section of highway tunnel construction risk management early-warning systems. First, the discussion of the mechanics of large-section tunnel, cross-section structure, construction methods and techniques, and the theory of tunnel construction risk management , according to the study of uncertainty risk identification and evaluation of large-section tunnel construction , and thus realize the scientific management and control of tunnel construction risk. Secondly, according to construction principle and select to build the establishment of mountain regions large-section of highway tunnel construction risk early-warning indicators. Then, pointing out that the principle of building early-warning model, the main method, running process, and establish mountain regions large-section of highway tunnel construction risk early-warning model based on this use of the BP neural network. And establish early-warning threshold value and division of early-warning signals, according to quantitative calculation of indicators, when the early-warning monitoring index exceeds early-warning threshold value, the system will send warning signals, and adopt corresponding measures in the light of Reality. Finally, according to actual casees, demonstrating the availability of BP neural network early-warning model.At present, Comparing China's mountain regions large-section tunnel construction risk management with countries of international advanced technology, there is great gap between them, Owing to lack of predictability,speculation,judgment and the single backward approaches of project risk management, the huge losses of accidents to owners and construction organization will be inestimable. The study of early-warning systems can predict the possibility of the risk before the potential losses occurred, changing the traditional risk of feed-back control, greatly reducing the losses of accident caused by risk. Therefore, the study of mountain regions large-section of highway tunnel early-warning system is of great significance.The completion of this thesis is based on Chongqing natural scientific research project, which is"Highway Mountain Tunnel Construction Risk Evaluate and System Study of Security Management"...