Analysis Of Lining Structure Diseases And Safety State Evaluation Of The Water Diversion Tunnel In Cold Area

China has a vast territory and abundant water resources,but the distribution of water resources is extremely unbalanced and the difference between the north and the south is large.Therefore,China has been built a series of water diversion projects,such as the South-to-North water diversion project,the Datong river to Huang river project,and the Yellow river to Qinghai project.The diversion tunnel is an important part of the water diversion project and plays an important role in the entire water diversion project.The diversion tunnel that constructed in the cold area of China is affected by the cold climate and bad geology during its long-term operation.The lining structure of the diversion tunnel has suffered a series of disease problems that endanger the safety of the lining structure.Therefore,this article uses a few method,such as literature analysis,field investigation,expert consultation systematically analyzed the types and causes of lining diseases,and on this basis,the evaluation index system for the safety of the lining structure of the diversion tunnel in the cold area is established,the safety state evaluation grades of the lining structure are divided,and the safety state evaluation model of the lining structure is constructed.As an example,the evaluation study is used on the 1# Nawei tunnel of the Datong river to Qin wangshuang river wherein the Qilian Mountain.By statistical the data,the importance of the evaluation factors is counted,the theoretical calculation model is systematically analyzed,and the diversion tunnel lining structure of cold area is completed based on the calculation results,and use the research results as a reference to determine whether to repair and strengthen the diversion tunnel lining structure to ensure the safe operation of the diversion tunnel.The paper focuses on analyzing the causes of diversion tunnel lining diseases in cold areas and researching the safety of lining structures.Mainly including common types and causes of diversion tunnel lining diseases,established the evaluation index system for safety studies of diversion tunnel lining structures in cold areas,divided it safety status level and constructed safety evaluation model.The preliminary exploration of the safety status of the lining structure of the diversion tunnel in the cold area has been completed,in order to provide a little reference for the safety management of the lining structure of the diversion tunnel.The main content and research results of the paper are as follows:(1)Through the literature analysis method,the common types and cause of the lining diseases of the diversion tunnel are summarized.The diversion tunnel built in the cold area is affected by the cold climate and bad geology,there are many diseases such as lining cracks,lining erosion and wear,lining frost heave damage and other diseases in the long-term operation process.The paper systematically analyzes the reason mechanism of the damage that caused in the lining structure.(2)Establish an evaluation index system for the research of the safety status of the lining structure of the diversion tunnel in the cold area.Based on the analysis of the disease mechanism of the diversion tunnel lining in the cold area,the evaluation index for the safety status of the diversion tunnel lining is determined,7 first-level indexes and 16 second-level indexes are obtained through the analytic hierarchy process,and the relevant specifications and paper are researched to list the qualitative and quantitative criteria for secondary indicators.(3)Establish the evaluation grade of the research on the safety status of the lining structure of the diversion tunnel in the cold area.With reference to the existing safety status classification of other traffic tunnels and hydraulic structures,through comparative analysis,the paper chooses four-level classification method to construct the evaluation level of the research on the safety status of the lining structure of the diversion tunnel in the cold area.It class A safety(minor damage to the lining),B safety(general lining damage),C safety(more serious damage to the lining),D safety(serious damage to the lining)evaluation.(4)Establish a research model for the research of the safety status of the lining structure of the diversion tunnel in the cold area.According to the characteristics of the fuzziness and unascertainability of its information,analyzing several common evaluation models,the unascertained measure theory that relatively accurate calculation and relatively simple operation is applied,and the actual measurement value of the index is based on the index.A single-index unascertained measure is established though the grade quantization of index,and used the weight calculation method combining the improved G2 and anti-entropy weight and minimum information entropy theory to calculate the evaluation vector of the multi-index comprehensive measure,and finally combines the confidence recognition criterion to determine the safety level of the lining structure of the section diversion tunnel.(5)Case study on safety of lining structure of diversion tunnel in cold area.Taking the1# Nawei tunnel that in the main channel of Datong river to Qinwangchuang as an example,collating the data obtained from statistical,substituting the data into the unascertained measurement theoretical model for evaluation,and calculating: 4+362 ～ 4+402 section structural safety is A,4+757.5～4+797 and 4+757.5～4+797 section structural safety is B,4+247.01～4+281.6 and 6+240～6+346.26 section structural safety is C.