微生物珊瑚砂桩成桩机理及复合地基承载变形特性研究

维护国家海洋权益，建设海洋强国，大规模岛礁工程建设势在必行、刻不容缓。我国已经或将要在部分岛礁进行陆域吹填，特殊海洋环境下吹填珊瑚砂的地基处理是一个具有挑战性的课题。本项目针对岛礁珊瑚砂地基处理的特殊性和建设“绿色工程、生态岛礁”的要求，基于微生物成矿技术，研发一套微生物珊瑚砂桩成桩新技术并揭示其成桩机理，进而提出一种新型复合地基处理技术——微生物珊瑚砂桩复合地基。然后通过系统的模型试验、理论分析和数值计算等对微生物珊瑚砂桩复合地基进行深入研究，得到微生物珊瑚砂桩单桩承载力和沉降特征，阐明考虑微生物桩特性的微生物珊瑚砂桩复合地基荷载传递机理和加固机理，揭示复合地基承载和变形特性，建立新型微生物珊瑚砂桩复合地基的承载力和沉降实用计算方法。研究成果为微生物珊瑚砂桩复合地基设计和应用提供理论支持和科学依据，将丰富和发展复合地基理论与实践，对推动新型微生物桩复合地基的发展和应用具有重要的科学意义。

To maintain the maritime rights and interests of country, and build up a nation with strong naval power, that calls urgently for large-scale engineering constructions on island reefs. Coral sand reclamations on some islands in China have been completed or will be carried out, and ground treatment of coral sand under special marine environment is a challenge. In view of the particularity of reef coral sand foundation treatment and the requirements of "green engineering and ecological reef" construction, this project develops a set of new technology of bio-mediated coral sand piles piling and reveals its pile-forming mechanism based on the microbially induced carbonate precipitation technology, and then propose a new composite foundation treatment technology -- bio-mediated coral sand piles composite foundation. Then systematical model tests, theoretical analyses and numerical calculations are carried out to study bio-mediated coral sand piles composite foundation, and the characteristics of bearing capacity and settlement of single bio-mediated coral sand pile are obtained. The load transfer and reinforcement mechanism of bio-mediated coral sand piles composite foundation considering the characteristics of bio-mediated piles are expounded. And the characteristics of bearing capacity and deformation of composite foundation are revealed. The practical calculation methods of bearing capacity and settlement of new bio-mediated coral sand piles composite foundation are proposed. These achievements provide theoretical and scientific basis for design and application of composite foundation with bio-mediated coral sand piles, and will enrich and develop theory and practice of composite foundation, it is of great scientific significance to promote the development and application of new bio-mediated piles composite foundation.