钙质砂注浆加固材料制备及固结体性能试验研究

注浆加固是解决岛礁钙质砂地基不均匀沉降问题的有效措施之一。根据钙质砂特性，选用超细硅酸盐水泥作为主体胶凝成分，纳米硅溶胶、粉煤灰和硫酸钙晶须作为辅料，依据单因素试验和正交试验的要求，制备了不同配比的注浆材料，测试了其凝结时间和相应固结体的力学性能。采用响应曲面法对试验结果进行模拟，探究各组分对各性能指标的影响，确定注浆材料最优配比。结果表明：将3种辅料按适当比例单独加入浆材中，均可提高不同龄期钙质砂固结体的抗压强度；当水泥掺量固定时，水灰比是影响浆液凝结时间和固结体强度的最主要因素；与水泥浆液相比，以最佳配比掺入辅料配制的注浆浆液能够更好地填充在钙质砂颗粒间，从而改变固结体的密实性，使其抗压强度明显增长。研究成果可为增强钙质砂地基注浆加固效果提供参考。

Experimental study on calcareous sand grout material preparation and performance of consolidated solids

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.