受建设时标准规范、施工水平及经济条件等限制，我国部分既有建构筑物抗震性能不足，亟待加固以提高其安全性。为突破传统地基处理技术无法处治既有建构筑物下可液化地基的工程困境，本项目采用室内试验和理论分析相结合的技术路线，对微生物产气降饱和度法处理既有建构筑物下可液化地基的关键科学问题开展研究。遴选适用于可液化地基降饱和度的微生物菌种并配制其培养基，分析微生物产气性能的影响因素；阐明微生物气泡在土体中的稳定性特征，提出土体中微生物气降饱和状态的表征指标和评价方法，并基于抗震性能提出微生物气处理可液化地基的饱和度控制方法；同时揭示微生物气泡介入对既有建构筑物地基变形的影响，在此基础上，构建既有建构筑物地基变形与基于抗震性能的微生物气降饱和度的协同控制方法。研究成果可为微生物气泡降饱和度法处理既有建构物下可液化地基的工程实践提供理论依据，为探索城市化进程中的低碳化模式与可持续发展做出贡献。

Due to the limitations of construction standards, construction level and economic condition, the seismic performance of some existing structures in China is generally insufficient, and it needs urgent reinforcement to improve its safety. In order to break through difficulties of the conventional liquefaction treatment technologies to treatment liquefiable foundation under existing structures, this study aims at developing a desaturation method by microbial gas to treat the liquefiable foundation under existing structures. By combining laboratory tests and theory analysis, soil microbial for the desaturation to liquefaction mitigation is selected and the influencing factors on the performance of microbial gas production is studied. The stability of microbial bubbles in the soil and the indicators and evaluation methods of microbial gas reduced saturation state is researched. A method of saturation control for liquefiable ground treated by microbial gas based on seismic performance is established. The influence of microbial bubbles intervention on the foundation deformation under existing structures foundation is revealed, and a synergistic control method is established for both the control of foundation deformation of existing structures and the microbial gas induced desaturation based on seismic performance. The research results will provide a theoretical basis for the practice of microbial gas induced desaturation to treat liquefiable foundation under existing structures, which will improve the seismic performance and safety of existing structures. It is expected that the research results contribute to the exploration of low-carbon mode and sustainable development in the process of urbanization.