Study On The New Type Of Grouting Material Behind Shield Tunnel

With the rapid development of China's national economy and social development and the acceleration of urbanization,urban and intercity rail transit is developing rapidly.The subway tunnel project growing,along with the extensive use of grouting materials,which requires the grouting material has cementitious properties and excellent mechanical properties,and puts forward some requirements on volume stability,impermeability and corrosion resistance performance and durability.This paper presents a new type of cement based grouting material,which has the characteristics of rapid setting,early strength,high stone rate,economic and environmental protection.In this paper,a new type of grouting material as the research object,study cementitious properties,mechanical properties,durability and durability evaluation,the main research results and conclusions are as follows:Experiment analyzes the gelling properties of the four kinds of materials: different water cement ratio of new grouting material,slurry,cement water glass and mortar are.The test results show that the gelation time of new grouting materials can be adjusted freely,no bleeding phenomenon,the stone was 100%,pH<10 will not cause corrosion to the lining,to meet the use requirements;The mechanical properties of different water cement ratio of new grouting material,water slurry,cement water glass and mortar of the four kinds of materials are analyzed by experiment,including compressive strength and axial compression strength of three combined with SEM micro structure analysis.The test results of new grouting material compressive strength has the early strength characteristics of confining pressure increases,the residual strength of three axial compression,and through SEM micro detection method,combining with the research of compressive strength.Comparative analysis of new grouting materials with different water cement ratio and the other three types of materials in the hydration products 28 days maintenance age and morphology.Through the analysis of the durability test of new grouting materials,water slurry,cement water glass and mortar anti erosion properties of groundwater,impermeability and volume stability.Describes the principle of consolidation hydration of cement grouting material,analyzed and summarized the grouting material in the groundwater under the condition of the change of compressive strength and corrosion mass loss,and through the water immersion test,analysis of conductivity of grouting material and dissolution process of change of the total material.As for the impermeability of grouting materials,two kinds of indexes,the permeability coefficient and the seepage pressure,are used to characterize the results.The results show that the permeability coefficient of the new grouting material is 28 d,which shows that the permeability of the material is 10-8.The volume stability of grouting materials,including shrinkage and cracking properties,the results show that the shrinkage of new grouting material 28 d is 1/23 of pure water slurry,1/31 of cement water glass,1/16 of mortar.New grouting material cracks time of 12 h later than other types of materials,in 1 d and 7 d respectively when the crack width is less than 0.4 mm and 3.5 mm,less than the other type of material,indicated that the new grouting material with excellent volume stabilityApplication of fuzzy comprehensive evaluation theory to evaluate the durability of grouting material.The durability of grouting material in grouting material evaluation of water resistant corrosion resistance performance,permeability,and volume stability as influence factors,using AHP to determine the weight of each factor,the results show that the new grouting material in the water cement ratio is 1,1.5 and 2,durability evaluation result is excellent.