Risk Identification And Evaluation Of The Construction Safety In Mountain Railway Tunnel Based On The Gray&Variable Weight Theory

With the rapid development of Chinese economic, a lot of trade promote the vigorous development of the transport sector. Especially the rail transport, which has large transport capacity and small transportation cost, has become the preferred way in staple and long-distance transport. So there’s a rapid development of railway construction in China recent years. As at the end2013, the railway mileage in China had reached to100,000km. The State Council promulgated the "National long-term railway network plan" which is in order to expand the size of the western railway network, and built the western railway network backbone. It also stated that the railway operating mileage of China will reach to120,000kilometers by the end of2020. The western railway construction of China has already been in rapid development era. The terrain of western area decided that the construction of the railway tunnel will be the most important and the most difficult work in the railway construction process next few years. So the safety evaluation for tunnel construction will be very important and necessary.In this context, this paper studied the mountain railway tunnel construction safety evaluation by referenced existing data and literature:Firstly, we collect the existing literature on security risk assessment, and analyze the results of the domestic and international scholars’research. On this basis, we collect the security incidents occurred during the construction of the tunnel over the past decade. By analyzing the accident type and the cause of the accident, we get the major risk factor checklist. At last, we get a mountain railway tunnel safety evaluation index system by integrating and changing the factors.Secondly, we use the AHP method to calculate the subjective weights of the evaluation index, and use the Group Decision Entropy Model approach to calculate the objective weights of the level of the experts. Then, by blending the two weights, we get the right combined weight of the evaluation index system. On this basis, we introduce the variable weights ideas to make the weights changes as the evaluation value of the indexes changes. Thus we avoiding the risks being overlooked in the system evaluation.Then, we build the gray clustering evaluation model of the mountain railway tunnel construction. By combining the variable weights to the gray clustering evaluation model, we introduce the gray ideas to evaluate the safety of the railway tunnel constructionFinally, we use the gray clustering evaluation model to evaluate a real case, the Wuzhishan tunnel which is the longest tunnel in Nanguang high-speed railway. By calculating the gray clustering model, we got the level of the safety in Wuzhishan tunnel construction. Then we analysis the results by connecting the actual situation. This paper is in order to provide some reference for the construction safety assessment of the similar tunnel projects.