Study On Structure Caculation Mode And Design Methodology Of Waterproofing Tunnel

With the development of high-speed railway in China, in order to make the station as close as possible to the city, there are lot large cross-section railway tunnels down-traversing the city, especially city suburbs need building underwater tunnel when down-traversing rivers and lakes. If tunnel is constructing and operating, and let groundwater resources emission and lose, which will cause the surface subsidence, and even the city buildings tilt and destruction, caused great impact on the ecological environment of the whole city, so only building waterproofing tunnel can reduce or avoid the influence on city environment. The waterproofing tunnel, although there are some relevant studies at home and abroad, but only limited to the case, and the current industry standard of waterproofing tunnel almost have no corresponding design method. Based on the above background, this thesis is researched in a meticulous and deepgoing way on the waterproofing tunnel structure calculated model and design method.This thesis study from waterproofing tunnel load mode, based on theoretical analysis, numerical simulation and field test as research means, analyze and study the structure bearing mechanism, water and soil pressure load mode, strata resistance characteristics and structure calculation model of the waterproofing tunnel, and through the performance, experimental research on performance index and constructive technology of waterproofing materials, finally form a set of design methods based on theoretical support of urban shallow buried waterproofing tunnel. The main conclusions and achievements are as follows:Firstly, initially proposed the secondary lining loads mode based on urban shallow buried waterproofing tunnel. For lithoid tunnel, secondary lining beard vertical surrounding rock pressure calculated by the current "code for design on tunnel of railway", and should consider the main power effect of invert subgrade reaction in Ⅳ、 V surrounding rock, horizontal lateral pressure coefficient suggested obtaining by measuring or taking the experienced value of1.0～1.5, hydrostatic pressure on secondary lining structure consider as all water head radial effect; for earthiness tunnel, secondary lining beard vertical surrounding rock pressure calculated by the current "code for design on tunnel of railway" as well, and consider the main power effect of invert subgrade reaction, horizontal lateral pressure according to the properties of soil respectively calculated by separate calculation or combining calculation principle of water and soil pressure; according to the strata conditions, hydrostatic pressure consider as hydrostatic pressure or calculated by combining calculation principle of water and soil pressure. Secondly, presents the structural calculation mode of waterproofing tunnel. Through comparative analysis between three calculation modes of waterproofing tunnel, obtain reasonable calculation mode of waterproofing tunnel, respectively adopts the peripheral spring foundation model, peripheral spring foundation+invert subgrade reaction model for internal forces analysis of structure, obtain the ultimate internal forces envelope diagram, according to the most unfavorable conditions for structural design.Thirdly, proposed the action law of water pressure in waterproofing tunnel, obtained the reasonable design method of waterproofing tunnel. Based on structural calculation model of waterproofing tunnel, through site test and numerical calculation to study the effects on the internal force of secondary lining structure caused by changing of groundwater level, illustrates influence of different water level in different parts of the tunnel is larger, should calculated respectively to the highest and the lowest water level during the construction and operation, proposed corresponding lining design method of waterproofing tunnel.Fourthly, through the laboratory experiment and site test, proposed main performance indexes of self-adhesive waterproofing board of waterproofing tunnel and form waterproofing constructive technology of waterproofing tunnel; introduce the "skin" type waterproofing ideology, waterproofing tunnel use self-adhesive waterproofing board laying full circle, one protection can be competent for high waterproofing requirement.This thesis presents the waterproofing tunnel’s load mode, structural calculation model, structural design method and waterproofing measures are successfully applied to the design and construction of Liuyang River Tunnel, Jinshazhou Tunnel of Wuhan to Guangzhou high-speed railway, and Liuyang River Tunnel of Changsha City, Xiangjiang Avenue. At present the three tunnels have been put into operation, feedback from site monitoring, evaluation and acceptance of the operation department, constructed waterproofing tunnel is good at waterproofing effect, less influence on surrounding environment, satisfy the needs of long-term operation, which demonstrates the correctness of the research results. Practice shows that the structural calculation model and design method of waterproofing tunnel proposed in this thesis is rationality and feasible, can be included in the relevant specification revision and further promoted in the future similar projects.