Experimental Study on the Diffusion Performance of Clay Shock Slurry in Shield Tunnel Construction
Research purposes:Clay shock method has gradually been introduced for auxiliary construction in the engineering of shield tunneling adjacent to existing structures.The diffusion performance of clay shock slurry in the stratum has a significant impact on the grouting effect behind the middle shield shell.Based on the self-developed grouting diffusion test system with constant-pressure for clay shock slurry,experiments were conducted to investigate the effects of water-powder ratio of liquid A,net grouting pressure,and permeability coefficient of stratum on the diffusion performance of slurry in the stratum,including final slurry amount,grouting end time,and diffusion distance.Combining the Bingham fluid diffusion model in sand,the theory and experimental diffusion distances of slurry were compared,and the reliability of the model test system and test results were verified.Research conclusions:(1)The yield stress and plastic viscosity of the clay shock slurry first increase and then decrease with the increase of the water-powder ratio of liquid A,and reach a local maximum value at the water-powder ratio of 3.0.(2)The diffusion behavior of clay shock slurry in soil shows a significant difference between filling diffusion and penetration diffusion.The filling diffusion stage mainly occurs in the first 30 seconds of injection,and can reach 70%-80%of the final slurry amount.The injection of slurry during penetration diffusion stage is slow,which closely related to the grouting end time.(3)As the water-powder ratio of liquid A increases,the final slurry amount and grouting end time first decrease and then increase,and as the net grouting pressure increases,the final slurry amount and grouting end time both increase.The diffusion distance of clay shock slurry is negatively correlated with slurry viscosity and positively correlated with net grouting pressure.(4)The influence of the diffusion distance is as follows:permeability coefficient of stratum>water-powder ratio of liquid A>net grouting pressure.(5)The results of this study can provide references for the engineering application and construction parameter selection of the clay shock method.
万方数据
维普
