Diffusion Mechanism of Compressible Synchronous Grouting Materials Based on Permeability Effect

Abstract:

At present， cement mortar is used as the grouting material for synchronous grouting， and the slurry permeates in the soil during grouting and consolidation， resulting in the decrease of slurry volume. If the subsequent grouting is not timely， it is easy to cause the grouting of shield tail gap not to be dense. The lightweight intelligent synchronous grouting material contains bubbles， because of its compression “elasticity”， with the consolidation and unloading of the slurry， although some of the slurry diffuses， the volume of the slurry remains unchanged in the gap between the tail of the shield， ensuring the density of the synchronous grouting. In this paper， the mapping relationship between density and pressure of the lightweight intelligent synchronous grouting material is studied， and the theoretical model of compression of lightweight intelligent synchronous grouting material is established. The principle of high density grouting of lightweight intelligent synchronous grouting material is qualitatively analyzed. According to the composition characteristics of lightweight intelligent synchronous grouting material， the consolidation and diffusion mechanism of compressible intelligent synchronous grouting material based on percolation effect is established. The results show that the volume of the slurry decreases with the increase of the pressure of the compressible synchronous grouting material. The experimental results show that the variable parameters of the pressure-density curve of the lightweight material have a strong correlation with the bubble content. The formation permeability coefficient has a significant influence on the consolidation diffusion distance of slurry. The larger the formation permeability coefficient is， the more significantly the consolidation diffusion distance of lightweight intelligent synchronous groutingmaterial is affected by the soil mechanical properties.

Key words:light weight;compressible;intelligence synchronous material injection;diffusion-consolidation mechanism