珊瑚砂的微生物固化及工程特性研究

With the development of ocean exploitation, more research on engineering properties and ground improvement technologies of coral sands are in need for the large-scale engineering construction on island reef. Coral sands, if properly used, will help to reduce the cost of construction material transported from the mainland. Coral sands need to be treated prior to its construction use because its brittleness, high compressibility and low bearing capacity. The proposed bio-mediated ground improvement technology for coral sands aim to improve engineering properties of coral sands. On basis of investigations carried out home and abroad, bio-mediated ground improvement technology for coral sands is researched, considering the high content of calcium carbonate, far from the mainland and the special marine environment, etc. Systematical experiments in laboratory and model tests are carried out on the bio-mediated ground improvement technology, by using advanced research methods including microbially induced carbonate precipitation, SEM scanning and multi-function rock triaxial test system, etc. The cultivation and preservation methods of the bacteria are be optimized, the mechanisms of bio-mediated ground improvement are discussed, the ground improvement technology is be optimized and the methods to evaluate ground improvement are established. The engineering properties and constitutive model of the improvement coral sands are proposed, thus laying foundation for engineering application. The achievement provide the theoretical basis for bio-mediated ground improvement technology for coral sands, which can be applied to the related engineering construction on island reef such as the foundation of roads，airfield runway and construction, and slope protection surrounded by sea, etc., and have important engineering practical value and good application prospects.

随着我国建设海洋强国重大部署实施的逐步深入，大规模岛礁工程建设需要对珊瑚砂的工程特性和加固处理等进行深入研究，以减少大规模从陆地运输建筑材料降低建筑成本。珊瑚砂具有颗粒易破碎、压缩性较大、地基承载力较低等特性，需要妥善处理；本项目提出微生物技术加固处理珊瑚砂。在已有研究成果基础上，考虑珊瑚砂主要成分为碳酸钙、远离陆地及所处的特殊海洋环境等问题，利用微生物成矿技术、SEM扫描、多功能岩石三轴测试系统等先进技术和测试手段，通过系统的室内试验和模型试验等对珊瑚砂微生物固化技术进行深入研究，优化细菌的培养和保藏方法，探讨固化机理，优化固化技术，提高固化效果，建立固化效果评价指标，揭示固化体的工程力学特性，建立相应的本构模型，为实际的工程应用奠定基础。研究成果为珊瑚砂的微生物固化技术提供理论支持，可用于道路、机场跑道、建筑物地基加固和环海护坡等岛礁工程建设中，具有重要的工程实用价值和良好的应用前景。