This study investigates harnessing of microbially induced calcite precipitation (MICP) to use in soil treatment to improve the engineering properties of loose sandy soils. Experiments were conducted in sand specimens using a channel, a pond, and four sand-columns. A bacterial treatment followed by a cementation reagent solution (CRS) was applied to trigger calcite (CaCO₃) precipitates. The submerged and surface percolation treatment methods were carried out in sand using CRS as the treatment solution. The treatment solution was maintained in an alkaline range (pH ≥ 7). The alkaline condition ensures active microbial induced calcite precipitation in the sand. The calcite precipitates bind the sand particles to increase the strength and stiffness of the soil matrix. The calcite bridged the sand particles and formed a biocemented water-impermeable crust layer (~ 2 mm thick). The calcite act as pore-filling material through the bioclogging process to reduce porosity and permeability. Permeability tests evaluate the effect of seepage control. The permeability was reduced to three order-of-magnitude (~ 99%) on the 7th day with little variation (~ 100%) until the 14th day. The compressive strength of the biotreated columns was between 585 and 875 kPa. The calcite content in the upper 10 mm thick in different columns was in the range of 11–14% and was gradually reduced from 9.8 to 3.4% below 10 mm. Hence, the observed 5–15% calcite content in natural biocemented products is comparable to MICP treated specimens. The scanning electron microscopic images show the calcite distribution patterns in the sand matrix.

这项研究调查了利用微生物诱发的方解石沉淀（MICP）进行土壤处理，以改善松散砂土的工程特性。实验是使用一个通道，一个池塘和四个沙柱在沙子样本上进行的。进行细菌处理，然后进行胶结剂溶液（CRS）触发方解石（CaCO ₃）沉淀。浸没和表面渗滤处理方法是在沙子中使用CRS作为处理溶液进行的。处理溶液保持在碱性范围内（pH≥7）。碱性条件可确保微生物在沙中产生积极的方解石沉淀。方解石沉淀结合砂粒，以增加土壤基质的强度和刚度。方解石桥接了沙子颗粒，形成了生物胶结的不透水的地壳层（约2毫米厚）。方解石在生物阻塞过程中充当孔隙填充材料，以降低孔隙率和渗透性。渗透性测试评估了防渗效果。渗透率在第7天降低到三个数量级（〜99％），直到第14天变化不大（〜100％）。经过生物处理的色谱柱的抗压强度在585至875 kPa之间。在不同的柱上，上部10毫米厚的方解石含量在11–14％的范围内，并从10毫米以下的9.8％逐渐减少到3.4％。因此，在天然生物水泥产品中观察到的5-15％的方解石含量与经MICP处理的标本相当。扫描电子显微镜图像显示了方解石在砂基质中的分布模式。