Development And Application Of Anti-seepage Grouting Material Behind The Lining Wall Of Urban Subway

At present,there are more than 60 cities with underground transportation system and operating mileage of more than 7000km.In the future,a large number of subway tunnels will be put into operation.The safety of urban subway construction and operation is related to the lives and properties of the people of the country,and its significance is self-evident.As the most common underground engineering disaster,grouting is the most common method to solve this kind of engineering problem.However,the traditional grouting materials have high water separation rate,poor volume stability of stone body and poor impermeability and durability,which results in little effect in some tunnel seepage control projects.Therefore,it is urgent to study the high efficiency grouting materials for such engineering problems.In this paper,according to the characteristics of lining leakage engineering,the maximum and the most comprehensive use of solid waste,taking the impermeability and volume stability of stone body as the main assessment index,a new grouting material for lining leakage treatment is developed.By means of mineral analysis,laboratory test,grouting simulation test and field test,the mechanical properties and engineering properties of the new grouting material for lining leakage are studied.The new grouting material for lining leakage control is successfully used in the lining leakage project of Qingdao station.The main work and achievements of this paper are as follows:(1)This paper expounds the design method and principle of grouting materials for lining leakage treatment,puts forward the engineering performance requirements of grouting materials based on the characteristics of urban subway lining leakage treatment project,reasonably explains the feasibility of cement with large amount of solid waste based on the theory of mineral hydration mechanism of cement-based materials and activation principle of pozzolanic matter,and combines the engineering site requirements of materials The performance optimizing agent is optimized.(2)This paper puts forward the principle of selecting the best proportion of each component of the new material,simplifies the proportion experiment design of the multi-component grouting material,and determines the best proportion of the new lining seepage control grouting material by studying the significant factors that affect the key performance of the material.It is determined that the best ratio of the matrix component of the grouting material is sulphoaluminate cement clinker:desulfurized gypsum:Fly Ash:bentonite:slag coal slag=22%:6.6%:2.6%:46.9%:6.3%:15.6%.Based on the hydration and gelling properties of the new cement-based materials and engineering requirements,the optimal ratio of the performance optimization agent is determined as the matrix component of the new cement-based materials:polycarboxylic acid water reducer:alkali activator:polymer=1:1.5%:2%:0.5%.(3)Based on the test of hydration heat and the analysis of micro mechanism,the engineering performance of the new lining leakage treatment grouting material stone body is explained from the aspects of hydration dynamics and material microstructure.The optimized new material has the advantages of high hydration heat release,high effective diffraction peak of effective minerals,high degree of interlinking of gel cement,small gel pore and dense internal structure of stone body,and has better engineering performance.(4)The laboratory test platform and mold for simulating the seepage and grouting of lining are designed.Through the environmental test of the grouting materials,the injectability,volume stability and impermeability of the new grouting materials are studied,and the applicability of the new grouting materials for the treatment of the seepage and leakage of lining is verified.And the research results are successfully applied to the leakage project of Qingdao Subway Station.