脲酶抑制剂作用下微生物加固某金属尾砂试验研究

Experimental Study of Microorganism Solidifying Tailing Sands Under the Action of Urease Inhibitor

微生物诱导碳酸钙沉淀过程是基于微生物产生脲酶而发生的。因此脲酶是影响该过程的重要因素。为了改善微生物加固尾砂的效果,考虑脲酶抑制剂能有效抑制脲酶活性、延缓尿素水解的作用,本文通过在微生物加固尾砂试验过程中引入了不同掺量的脲酶抑制剂,并对加固后的尾砂柱体进行宏观力学试验与微细观检测,系统分析了脲酶抑制剂对微生物加固尾砂的效果。结果表明:适量的脲酶抑制剂可较大程度地延长巴氏芽孢杆菌迟滞期,可改善碳酸钙沉淀分布的均匀性,可提升微生物固化后尾砂试样的力学性能。其中,脲酶抑制剂的掺量为0.1%时,砂柱试样具有明显的剪切破坏模式,其剪切峰增长13.26%,有效黏聚力增长11.82%,有效内摩擦角增长6.85%,碳酸钙生成率同比增长了34.17%,孔隙率降低了46.90%。

Based on the production of urease by microorganisms,the microbially induced calcium carbonate precipitation process occurred.Therefore,an important factor affecting this process is urease.In order to improve the reinforcement effect of MICP technology on tailing sands,considering that urease activity can be effectively inhibited and urea hydrolysis retarded by urease inhibitor,in this paper,different mass fractions of urease inhibitors was introduced during microbial reinforcement of tailing sands tests,and the reinforced tailing sand column was also subjected to the mechanical test and the analysis of micro-structure.The effect of bio-cemented sand by urease inhibitors was comprehensively evaluated.The result shows that the appropriate amount of urease inhibitor can significantly prolong the Bacillus retardation period,and improve the uniformity of calcium carbonate precipitation distribution and the mechanical properties of tailing sand specimens by microbially curing.Among them,the inhibitor of mass fraction at 0.1%,the sand column specimens had an obvious shear damage pattern,this shear peak increased by 13.26%,the effective cohesion increased by 11.82%,the effective internal friction angle was 6.85%,the calcium carbonate generation rate increased by 34.17% year-on-year,and the porosity decreased by 46.90%.