中文摘要：

微生物诱导生成碳酸钙沉淀（MICP）技术是一项新兴的原位灌浆技术,通过微生物和钙盐作用形成碳酸钙沉淀可改善可液化砂土的抗液化特性。NH4＋作为表征碳酸钙结晶过程的重要因子,可充分反映对可液化砂土的改良效果。选用巴氏芽孢八叠球菌,采用Ca（CH3COO）2、Ca（NO3）2和Ca Cl2三种钙盐与尿素混合溶液的营养盐,探讨采用NH4＋来表征可液化砂土的微生物固化过程。结果表明：NH4＋离子浓度变化能够表征MICP对可液化砂土改良的效果,其中Ca（CH3COO）2营养盐改善可液化砂土效果最佳;营养盐的用量也对可液化砂土的加固效果有明显的改善。通过对固化后试样的渗透性和超声波速的测定,也验证了加强效果。

英文摘要：

Microbial induced calcium carbonate precipitation （MICP） is a new in situ grouting technology. It can improve the flow characteristics of liquefiable sandy soil through microbial and calcium salt reaction and become calcium carbonate precipitation. Ammonium （NH4 ＋ ） , as an important factor of characterizing CaCO3 crystallizing process, can fully reflect the effect of treatment on liquefiable sand. In this paper, aerobic Sporosarcina pasteurii was used, the mixed solution （urea and three calcium salts solution） was selected as bacteria solution and nutritive salt solution respectively, and NH4 ~ characterization on microbial solidification process was also studied. The results showed that changes of NH4 ＋ concentration could characterize the effect of MICP on liquefiable sand improvement. Among Ca（ CH3COO ） 2, Ca （ NO3 ） 2 and CaC12 solution, the former was the best. The amount of nutrient salt consumption also significantly improved the solidification effect of liquefied sand, which was verified by the estimated permeability of samples and ultrasonic experiments after solidification.