为进一步提升酶诱导碳酸钙沉淀（EICP）技术的固化效果，本文采用EICP联合高岭土对标准砂进行固化处理，设置高岭土掺量与养护时间两个试验变量，开展了不同变量组合条件下固化砂的宏微观试验研究。试验结果表明：EICP联合高岭土固化砂的无侧限抗压强度随高岭土掺量与养护时间的增加持续提高，4%高岭土掺量养护14天的抗压强度为722.19 kPa，是纯EICP固化砂的13.15倍；碳酸钙沉淀率不会随着养护时间和高岭土掺量的增加持续提升，3%高岭土掺量养护7天的碳酸钙沉淀效率最高；随高岭土掺量的增加，孔隙度先减小后增加，高岭土掺量为2%时，孔隙度最小；掺加高岭土前后固化砂的孔隙由以中孔为主（占比超过90%）转变为以小孔为主（占比80%左右），孔隙结构得到明显改善；EICP联合高岭土固化砂颗粒间沉积的碳酸钙晶体以球霰石为主，呈堆叠状填充于砂粒间隙并覆盖在砂粒表面，可显著提升砂粒间的胶结作用。

To enhance the solidification effect of enzyme-induced calcium carbonate precipitation (EICP) technology, this study employed EICP combined with kaolin to treat standard sand for solidification. Two experimental variables were set: the amount of kaolin added and the curing time. Macroscopic and microscopic experiments were conducted on solidified sands under different variable combinations. The experimental results revealed that the unconfined compressive strength of the EICP combined with kaolin solidified sand continued to increase with the increase of kaolin content and curing time. The compressive strength after curing with 4% kaolin content for 14 days was 722.19 kPa, which was 13.15 times that of pure EICP solidified sand. The calcium carbonate precipitation rate did not continue to increase with the increase of curing time and kaolin content. The efficiency of calcium carbonate precipitation was highest when cured with 3% kaolin content for 7 days. As the kaolin content increased, the porosity first decreased and then increased, with the minimum porosity observed at a kaolin content of 2%. The pore structure of the solidified sand before and after adding kaolin changed from being dominated by medium pores (accounting for over 90%) to being dominated by small pores (around 80%), indicating a significant improvement in pore structure. The calcium carbonate crystals deposited between the particles of the solidified sand with EICP combined with kaolin were mainly aragonite spheres, which were stacked and filled in the interstices between sand particles and covered the surface of sand particles, significantly enhancing the bonding effect between sand particles.

国家自然科学(52268059),江西省自然科学基金面上项目(20232BAB204079)