Abstract: Grouting reinforcement is one of the effective measures to solve the uneven settlement of calcareous sand ground. In term of the characteristics of calcareous sand, ultrafine portland cement was selected as the main grouting material, nano-silica sol, fly ash or calcium sulfate whisker were used as auxiliary materials. According to the requirements of single factor and orthogonal tests, grout with different proportions was prepared, and the setting time and compressive strength of grout and consolidated calcareous sand were tested respectively. Meanwhile, response surface method was used to simulate the test results to analyze the influence of each component on each performance index and to determine the optimal ratio of grouting materials. The results show that the compressive strength of consolidated body at different ages can be improved when the three kinds of excipients are added separately to the slurry in proper proportion. When the cement content is fixed, the water-cement ratio is the most important factor affecting the setting time of slurry and the strength of consolidated body. Compared with pure cement grout, the grouting grout prepared with the best proportion of additives can better fill into the intergranular space of calcareous sand, thus changing the compactness of the consolidated body and increasing its compressive strength significantly.

Key words: portland cement, calcareous sand, grouting material, orthogonal experiment, compressive strength