Study on the Influencing Factors of Enzyme Induced Carbonate Precipitation and Mineralization

相关研究表明，EICP固化土体能够显著改善土体的力学性能，其改善效果与碳酸钙生成量、晶体类型、脲酶浓度、胶结液浓度等因素有关。本文拟采用正交试验，以碳酸钙生成量为因变量，评价脲酶浓度、胶结液浓度、脱脂奶粉浓度、pH值和静置时间对碳酸钙生成量的影响，进而得到矿化反应的优化条件。试验结果表明：豆粉浓度和胶结液浓度影响因子主效应显著，而pH值、脱脂奶粉浓度以及静置时间对EICP反应的碳酸钙生成量影响不显著。各影响因子对碳酸钙生成量影响的主次顺序为：胶结液浓度 > 豆粉浓度 > 静置时间 > pH值 > 脱脂奶粉浓度；单位体积内获得CaCO3生成量的最优组合为：豆粉浓度为200 g/L，胶结液浓度为1.50 mol/L，脱脂奶粉浓度为2 g/L，pH为7，静置固化时间为120 h。Related studies have shown that the solidified soil by EICP can significantly improve the mechanical properties, and the modification effect is related to factors such as carbonate production, crystal type, urease concentration, and cementation concentration. This article intends to use orthogonal experiments with carbonate production as the dependent variable to evaluate the effects of urease concentration, cementation concentration, defatted milk powder concentration, pH value, and settling time on carbonate production, in order to obtain optimized conditions for mineralization reaction. The experimental results indicate that the urease concentration and cementation concentration are significant factors, while pH value, defatted milk powder concentration, and settling time have no significant effect on the production of carbonate. The effects of various influencing factors on the production of carbonate is: cement concentration > urease concentration > settling time > pH value > defatted milk powder concentration. The optimal combination for obtaining CaCO3 generation per unit volume is: soybean powder concentration of 200 g/L, cementation concentration of 1.50 mol/L, defatted milk powder concentration of 2 g/L, pH of 7, and settling time of 120 hours.