MICP固化松散砒砂岩抗水蚀机理研究OA北大核心CSTPCD

[Objective]The aims of this study are to explore the effect of MICP solidified loose Pisha sandstone,and to provide solutions and theoretical basis for reducing soil erosion in Pisha sandstone area.[Methods]The effects of the bacterial solution concentration and curing frequency on the mechanical properties of MICP-cured Pisha sandstone and its resistance to water erosion were investigated at the macro-scale(penetration strength,rainfall erosion,etc),and the mechanism of water erosion resistance of Pisha sandstone-cured soil was revealed at the micro-scale(X-ray diffraction,scanning electron microscopy,Fourier transform infrared spectroscopy,thermal analysis).[Results]For the same curing time,when the concentration of the bacterial liquid(OD600)was 0.8,the curing effect was the best,and its strength was increased by 20％～50％compared to the other concentrations.When the optimal concentration of the bacterial liquid was 0.8 and the curing frequency was five times,the Pisha sandstone attained a good strength and water erosion resistance,and the total rain erosion soil loss was reduced to 10％of the amount before curing.When the bacterial liquid concentration was 0.8,the calcium carbonate content was the greatest,and most of the calcite phase occurred as rhombic blocks and were more densely distributed.With increase of curing time,the cementation and filling effects improved.[Conclusion]The bacteria and their extracellular polymeric substances(EPS)in the MICP acted as nucleation sites,were involved in calcium carbonate localization and growth and development,and improved the stability of the calcium carbonate.The EPS,organic matter,calcium carbonate,and Pisha sandstone minerals involved in the formation of the intermolecular hydrogen bonds and other functional groups enhanced the cementation capacity of the calcium carbonate and further improved the strength of the Pisha sandstone and its resistance to water erosion.