Design,Test And Engineering Application Of Composite Waterproof And Drainage System For Tunnels

With the continuous construction and development of tunnel projects,more and more tunnels in the construction and operation process,due to the deterioration of the drainage system can not play its proper function,resulting in the tunnel suffered from groundwater hazards of varying degrees,the phenomenon of water leakage.As more and more tunnels are put into use,the problems caused by the deterioration of the tunnel drainage system will have a wider and wider impact and will be more and more difficult to deal with.To carry out prevention and control work after the lining leakage phenomenon,to a large extent,is no longer a rainy day,but a mending of the sheep.This paper relies on the Ningbo Transportation Science and Technology Project:Research,Development and application of new composite tunnel drainage prevention system(201906),firstly,through on-site research,the main drainage prevention materials used in the current tunnel and the defects,and analyze the causes of water leakage.And in response to this status quo,a composite anti-drainage system with additional drainage plates between tunnel flashing and secondary lining is proposed,which can continue to drain after the drainage blind pipe is blocked and the flashing is cracked,improve the state of water pressure behind the lining,and effectively reduce the phenomenon of lining water leakage.Through a combination of indoor drainage tests,scaled-down model tests and field tests,the drainage performance of the drainage board was investigated,and the drainage capacity and water pressure distribution law of the composite anti-drainage system under different working conditions were studied.(1)Analysis of the causes of tunnel water seepage: Through on-site research,the waterproof and drainage materials usually used in highway tunnel drainage prevention systems were summarized,and the defects in the current drainage prevention systems in actual projects(such as blind pipe blockage,cracking of flashing,etc.)were pointed out,and combined with the results of on-site testing of 27 highway tunnels,the resulting lining cracking,water seepage and other diseases were statistically classified,and the main causes of water seepage were summarized and analyzed.(2)tunnel composite anti-drainage system development: waterproof plate cracking for groundwater transport provides a seepage channel,the blind pipe is partially blocked to exacerbate the occurrence of water seepage,for this cause of water seepage,designed a composite anti-drainage system with additional drainage plate between the waterproof plate and the secondary lining,the anti-drainage system has adjustable,anti-blocking,easy maintenance characteristics.(3)Tunnel composite drainage prevention system experimental research: The additional drainage board installed in the composite drainage prevention system was studied,and the drainage capacity and anti-blocking capacity of different drainage boards and geotextiles were tested using self-developed drainage performance test devices,and the drainage characteristics of different drainage boards were studied based on the test results.According to the similarity theory,based on the support system that satisfies the similarity ratio of permeability coefficient as the core,a three-dimensional visualization seepage model test system of the tunnel was developed,and the data of drainage volume and water pressure under normal drainage and partial blockage conditions were recorded during the test,and the water pressure distribution of the composite drainage prevention system and the conventional drainage prevention system under different conditions and the change law of water pressure in the process of water seepage management were compared and analyzed(4)Tunnel composite drainage prevention system(4)Engineering application of composite tunnel drainage prevention system: A typical section of a tunnel in Ningbo was selected to carry out the engineering application of the composite drainage prevention system,and two different drainage boards(convex hull drainage board and capillary drainage board)were set up to monitor the water pressure and support pressure behind the lining,and the actual application effect of the composite drainage prevention system was evaluated based on the results of the field test.The composite anti-drainage system can provide reference for the design,construction and operation of subsequent tunnel drainage systems,and provides a new idea for tunnel leakage protection and management,which can be gradually promoted and applied to similar projects.The research results of the thesis have an important guiding role in ensuring the long-term operational safety of tunnels,and have greater economic value and social benefits.