Research Of Scheme Evaluation Of Mountain Railway Location Based On Uncertainty Analysis

China is a mountainous country and the mountainous area accounts for about two-thirds of the entire land area. The mountain area of our country basically relies on the long trunk line to undertake the transportation task. Since the founding of the people's Republic of China, our country have built many mountain long trunk lines, such as Baoji-Chengdu Chengdu-Kunming?Nanning-Kunming?Neijiang-Kunming?Chongqing-Huaihua and so on, having formed a mountain railway network basically. However, the length of the road network is not commensurate with the land area and population number, for example, the 12 western provinces and autonomous regions accounte for 71.5% of China's land area,, while the railway commercial mileage accountes for only 36.6% of the whole country. With the constantly advancing of the Western development and other region development strategy, the total mountain railway network is still a developing "bottleneck". Therefore, the State proposed to expand the size of the main western road network and form the western railway network backbone railway network plan.Mountain railway not only bears most of the long-distance freight and passenger transport task in the region, but also plays a very important role on the development of economic, political, technological, military and other aspects of the railway surrounding area. So, whether the route scheme is choosed objectivly and reasonably or not, not ony will affacte the investment, construction cycle, scale and operational efficiency of the project itself, but also will have a profound impact on the regional transportation needs, the regional economic, social development and national defense construction and other aspects. The whole process of railway location is the scheme comparison and selection process. Therefore, the establishment of a scientific method for the scheme evaluation of the railway location is important for the successful implementation of the whole mountain railway construction project and even lead the railway line selection design to the modern design method.The scheme evaluation and selection of railway location is a complex and multi objective decision making process involving a large number of evaluation indicators, influenced by many external factors and uncertainties. It have the characteristics of a large number of qualitative indicators, affected by the macroeconomic situation obviously and Large natural disaster risk and so on, but the traditional railway scheme evaluation and selection model considered inadequate for these uncertainties and when the qualitative indicators and quantitative indicators appear to cross, the difference of economy is not big, also lack appropriate evaluation methods. This has resulted in the current scheme evaluation work of mountain railway location is still in a large extent dependent on expert decision-making and leadership clappers, lack of scientific evaluation system and method. Based on the data of scheme decision making of mountain railway have been built, this paper put forward a quantitative decision method and established a scheme evaluation model of mountain railwav location that has the universality by making full use of the existing experience and technology and absorbs the new results of the contemporary world science and technology development, such as the multi objective decision-making, utility theory, risk analysis, reliability mathematics, stochastic process theory and so on. The main work and conclusions are as follows:(1) Based on the theory of uncertain multiple attribute decision making, the qualitative indexes and expert opinions in the scheme evaluation of railway location which are difficult to directly quantify are converted. According to the principle of uncertainty reasoning of cloud model, an effective quantification of qualitative indexes is achieved through the use of cloud generator after experts evaluated indexes using linguistic variables. Then, by using the method of deviation to calculate the index weight, the influence of the expert's subjective opinion caused by subjective weight method such as AHP is avoided. Finally, the projection method is use to select the optimal scheme. A scheme selection model of mountain railway location based on cloud model and projection is estabilished.(2) Based on the multi attribute utility theory, the utility value is used as the representation of the scheme value without changing the existing scheme index calculation method. Different utility functions are choosed to reflect the influence of the macro economic situation on the scheme selection which is equivalent to change the evaluation system. Firstly, interval numbers are introduced to quantify qualitative indicators. Then, the utility functions are defined to quantify the impact of macroeconomic situation in the case of indicators of each scheme unchanged objectively. Finally, the projection method is use to select the highest utility scheme. A scheme selection model of mountain railway location based on the utility theory is estabilished.(3) According to the risk analysis theory, the low frequency and large disaster of railway is defined. A joint probability model is proposed to calculate the probability of the earthquake and use the P-? type cure and the expected failure probability to calculate the probability of the flood exceeding the design flood. Based on the Wenchuan earthquake statistical data, the forecasting method for railway economic loss by earthquake damage are established, including the direct loss of the railway line engineering caused by the earthquake and the railway capacity loss values as the indirect economic losses. Then, the risk is divided into three categories of acceptable risk, tolerable risk and intolerable risk and the 10% and 1% of the expectation annual conversion project operation cost are proposed as the criteria for the intolerable risk and acceptable risk respectively. Proposed the corresponding scheme selection is:if the large disaster risk is in the acceptable risk area, using traditional evaluation method selection scheme; If the risk is tolerable, it is necessary to use the expectation annual conversion project operation cost method to carry out economic evaluation, then select with the bypassing scheme; if the risk is intolerable, it can only choose the bypassing scheme. At the macro-decision-making technology level, the risk control program is established through scheme selection between through scheme and bypassing scheme.(4) Based on the reliability mathematics theory, the definition of the reliability of railway line system and the corresponding reliability evaluation index are put forward. Then, The railway line system is taken as a series repairable system composed of the roadbed?bridge and tunnel. The renewal process principle is used to calculate the reliability index of the railway line system in earthquake and flood threat area when the normal working hours are subject to exponential distribution or general distribution and the average repair time of the project is known. And then, the expected availability is protosed to use as the scheme evaluation index of the railway in ebris flow and landslide area. Finally, the formula of multi-disasters comprehensive availability is established. So, the reliability evaluation model of railway line system in mountainous area is established.Therefore, a scheme evaluation method of railway location in mountainous area is put forward based on uncertainty analysis.