基于微生物矿化作用的砂土加固实验研究
毕业论文关键词：加固砂土;微生物诱导碳酸钙沉淀（MICP）;砂土
Experimental Study on Sandy Soil Improvement using Microbial Induced Calcite Precipitation (MICP)
Abstract：With rapid development of economy global and increase of global population, demand for infrastructure construction continues to expand. During the large-scale construction of municipal infrastructure, it is hard to avoid to encountered some weak soil which can not meet the corresponding engineering requirements. Unlike traditional cementing materials, this paper studied on microbial induced calcite precipitation (MICP) to improve soil consolidation ability, injecting bacteria solution and urea, Ca2+ and nutrient broth into loose sand in order to bind soil particles together by CaCO3 and improve physic-mechanical properties, MICP is an effective and environmental friendly soil improvement method compared with traditional methods. This paper shows data which based on scientific basis show that it will be a broad engineering application future in soil improvement. The study results were listed as follows:(1) Firstly, this paper focuses on the bacterial (Sporosarcina pasteurii) culture and its urease activity which affected by temperature and pH. The optimum conditions for Sporosarcina pasteurii growth and its urease activity are 30℃,pH=9, which provides suitable parameters for the following experiments.(2) Secondly, different ranges of particle size and porosity will directly affect MICP process. The pore space of sand with smaller particle size can be tightly filled and a higher proportion of effective calcite crystals can be obtained. Hence, the bio-cemented sand is able to present a higher strength due to the stronger structure established by the calcite crystal clusters. In addition, when the concentration of cementation solution is 0.5M, it gives enough Ca2+ and urea for MICP to enhance sandy soil improvement effect. The effect of randomly distributed discrete fiber on the mechanical properties of MICP-treated sandy soil is to decrease the brittleness of specimens.
Key words: soil improvement; microbial microbial induced carbonate precipitation; sandy soil
目 录
摘要1
关键词1
Abstract1
Key words2
引言3
1试验材料与方法3
1.1试验材料3
1.1.1试验用微生物3
1.1.2试验用砂3
1.1.3胶结液3
1.1.4试验所用模具4
1.2试验方法 4
1.2.1微生物数量检测4
1.2.2微生物活性检测4