微生物灌浆加固土体研究进展

Advances of soil improvement with bio-grouting

水泥和化学浆材是土体加固中最为常用的胶凝材料,但由于存在着高能耗、高污染排放和高成本等缺点而限制了它们的应用。微生物灌浆加固技术是最近发展起来的一种新型的土体加固方法,通过向松散砂土中灌注菌液以及营养盐,利用微生物矿化作用在砂颗粒间快速析出方解石凝胶,改善土体的物理力学性质。系统总结了国内外关于微生物灌浆加固土体的室内及现场试验研究,同时对固化土体的工程特性、原位无损测试方法以及灌浆效果的影响因素等进行了论述。研究表明,微生物灌浆技术具有施工扰动小、灌浆压力低、环境友好等优势,并可显著提高土体的强度、刚度及抗液化性能,在土体加固领域有着非常广阔的应用前景,但关于微生物固化土体的耐久性以及灌浆的经济性等问题仍需进行深入的探讨与研究。

As cementing materials, cement and chemical grouts have often been used for soil improvement. However, high energy consumption, high-pollution discharge and high cost restrict their applications. A new soil improvement method, called bio-grouting reinforcement technology, has recently emerged, which is based on microbial induced calcite precipitation by injecting bacteria solution and nutrient into loose sand for the purpose of binding soil particles together and improving its physico-mechanical properties. Laboratory and field experimental studies of bio-grouting treated soils are systematically summarized. The engineering characteristics of bio-treated soils, non-destructive geophysical process monitoring method, and factors influencing the improvement effect are also discussed. The research results show that the bio-grouting process has many advantages such as small disturbance, low grouting pressure, less environmental harm, and remarkable treatment effect on improving the engineering properties of the soil （e.g. strength, stiffness, liquefaction resistance）, which make it a broad engineering application prospect in soil improvement. However, the durability ofbio-treated soils and economy of bio-grouting still need discussing and investigating further.