Laboratory study on use of soybean urease-induced calcium carbonate precipitation with xanthan gum for stabilization of desert sand against wind erosion
摘要
The technology of soybean urease-induced calcium carbonate precipitation (SICP) is a new environmentally-friendly soil improvement technology. Xanthan gum can also be used as a soil cementation material. This study combines the technology of soybean urease-induced calcium carbonate precipitation and xanthan gum to optimize the former. It is found that the xanthan gum can further improve the surface strength of SCIP-improved sand. The surface strength increases with the increase of the concentration of soybean urease and xanthan gum. The wind erosion tests are carried out on the sand samples with different treatment levels using pure wind and wind mixed with solid particles. The samples treated only by SICP technology have relatively strong resistance to wind sand erosion. The addition of xanthan gum further improves their resistance by showing a lower erosion rate of the samples. In addition, the results indicate that in the wind erosion tests, the presence of solid particles have a strong erosion effect on the deterioration of the sand surface. The erosion rate (mass loss %) of the samples with the lowest strength is only 3.8% under the wind of 15 m/s and 1 h in the tests with pure wind, while under the same condition, the erosion rate is 66.7% in the tests using wind mixed solid particles. It is also found that there is a strong positive correlation between the wind erosion resistance and the surface strength of the treated soil. The microstructure of the treated sand samples is investigated by the SEM. It is observed that the cementation between the calcium carbonate and the soil particles becomes stronger due to the binding and the hardening effects of the xanthan gum.