Reasonable Utilization Polymers to Improve Enzyme-Induced Carbonate Precipitation Method for Soil Stabilization

As a soil reinforcement method with minimal disturbance to the natural environment, enzyme-induced carbonate precipitation (EICP) technology has been increasingly applied. Due to the smaller size of enzymes in EICP technology, they are more likely to enter the small pores of clay, making EICP more suitable for clay. However, the short residence time of biological enzymes and insufficient nucleation sites for calcium carbonate can affect the effectiveness of EICP in clay application. Therefore, this study selected four natural legumes to extract urease, and added sodium alginate, xanthan gum, and guar gum polymers as calcium nucleation site materials. By studying the influencing factors of urease activity and CaCO3 yield, suitable reinforcement conditions and materials can be selected. The research results indicate that the urease activity of the jack beans is relatively high, and when the cementing solution concentration ratio and the glue enzyme ratio were both 1∶1, the CaCO3 yield was more efficient. Based on this, when 0.10% sodium alginate is added, the amount of calcium carbonate can reach up to 2.75 g, which is an increase of 2.6 times, and the mineralization rate of calcium ions also reaches 78.7%, which is a significant improvement. Strength tests and microscopic observations also indicate that the reasonable addition of polymers is beneficial for improving the application effect of EICP in clay.