Physical Properties And Ratio Optimization Of Synchronous Grouting Material For Submarine Shield Tunnel

In recent years,with the further development of economy in China,the situation of extending traffic network to sea area is becoming more and more common,and the cases of using shield method to build traffic tunnel across sea area is increasing gradually.The construction of shield tunnel in sea environment will face more challenges due to the complex and changeable sea environment and the corrosion of sea water.As an important link in shield tunnel construction,the physical and mechanical properties of the grouting materials used in the fresh water environment of the land area will be changed,and the water pressure of the synchronous grouting environment is generally high.The current studies pay more attention to the shield tunnel synchronous grouting material used in fresh water environment,and seldom takes into account the influence of sea area environment on synchronous grouting.In this paper,laboratory experiments are used to study the physical and mechanical properties of synchronous grouting materials for shield tunnels in the sea environment,and computational fluid dynamics(CFD)methods are used to study the effect of rheological parameters on synchronous grouting diffusion.The major works are as follows:(1)On the basis of a high concentration single component inert mortar used in Su'ai tunnels,the influence of seawater on mortar collapse,consistency,water retention,setting time,shearyield strength,sample strength and shrinkage rate was comprehensively analyzed.(2)Based on the mortar used in Su'ai tunnels,orthogonal test was used to studied the influence of the change of each component content on the physical and mechanical properties of the mortar.(3)Based on the results of the experiment,the ratio of the grouting material was optimized by the comprehensive balance method based on range analysis and multi-objective programming method based on regression analysis.The optimum mix ratio is as follows: sand 4.44 kg,fly ash 0.7kg,bentonite 0.2 kg,hydrated lime 0.53 kg,cement 0.11 kg,water 1 kg.(4)The Computational Fluid Dynamics method was adopted to simulate the process of mortar diffusion in the tail void,The flow pattern of mortar and the influence of rheological parameters of mortar on flow diffusion process was studied.