In view of the water inrush disaster in karst area, the slurry has the problems of poor dispersion resistance and low retention rate in the process of grouting and plugging. In this paper, Portland cement is used as the matrix material, and water glass is added to obtain cement-water glass slurry. Then polyacrylamide, iron powder, xanthan gum and guar gum are used as admixtures to develop a new type of grouting material suitable for dynamic water plugging of water channels. The response surface regression model was constructed by Design-Expert software, and the effects of polyacrylamide, iron powder, xanthan gum and guar gum on the setting time, slurry retention rate and compressive strength of the new cement-water glass slurry were analyzed. Combined with the desirability function, the optimal ratio of the new cement-water glass slurry was obtained. The results show that the interaction of each two admixtures has a significant effect on the setting time of the slurry; the single factor of xanthan gum and iron powder had a significant effect on the slurry retention rate. The single factor has a significant effect on the compressive strength of the slurry, and the amount of polyacrylamide has the greatest influence. The model predicts the optimal ratio: polyacrylamide content is 0.6%, xanthan gum content is 0.7%, guar gum content is 0.4%, iron powder content is 29.96%, which can provide a reference for the multi-objective optimization of the mix ratio of the new cement-water glass slurry.

Keywords: Water inrush, Response surface method, Craving function, Mixing ratio optimization.