基于产脲酶微生物诱导矿化的淤泥吹填土加固机理研究

There are many disadvantages in the current treatment methods of silt dredger fill, such as time-consuming, high energy consumption and high cost, and a new method of environmental protection and high efficiency is urgently needed. According to this situation, this project intends to study the reinforcement technology of silt dredger fill base on urease producing bacteria induced mineralization through a series of laboratory experiments. Through the mutagenesis and screening of Sporosarcina pasteurii, and the separation and culture of microorganisms in the silt dredger fill, the strain suitable for microbial induced mineralization will be found. Through laboratory model test of grouting, combined with macro mechanical test and micro test technique, the adsorption characteristics of clay particles on microbial strains will be analyzed, and the hydrolysis law of urea, the characteristics of mineral growth and strength formation mechanism of the silt dredger fill will be explored. Then the mechanism of mineralization and influencing factors in the silt dredger fill will be explored based on the above results. Further more, the engineering properties of the reinforced soil will be analyzed. The research results will lay the foundation for the application of microbial technology in the field of silt dredger fill foundation treatment.

当前淤泥吹填土地基的处理方法大多存在着工期长、能耗大、费用高等缺点，亟需发展一种环保高效的新处理方法。针对这一现状，本项目拟通过一系列室内试验，开展产脲酶微生物诱导矿化的淤泥吹填土加固技术研究。通过巴氏芽孢八叠球菌的诱变、筛选，以及淤泥吹填土中微生物的分离、培养，寻求适合进行诱导矿化的微生物菌株。通过室内模型灌浆试验，结合宏观力学试验和微观测试技术手段，分析黏土颗粒对微生物的吸附特性，探索微生物诱导矿化过程中的尿素酶解规律、矿物生长演变特征及淤泥吹填土的强度形成过程，揭示淤泥吹填土中产脲酶微生物诱导矿化的胶结作用机理及影响因素，分析微生物加固后的土体工程特性，为微生物技术在淤泥吹填土地基处理领域内的工程应用提供参考。

微生物诱导碳酸钙沉淀（MICP）技术是近年来微生物岩土工程研究领域的热点，逐步在文物修复、微生物水泥、污染土治理、砂土地基改良等方面应用于工程实践，但在软土地基处理方面还鲜有报道。本项目通过一系列室内试验，开展了MICP加固软黏土的技术研究。通过巴氏芽孢八叠球菌的培养、筛选，获得了适合进行诱导矿化的微生物菌株。通过拌和法和室内模型灌浆试验，结合宏观力学试验和微观测试技术手段，分析了MICP过程中矿物生长演变特征及软黏土的强度形成过程，揭示了软黏土中产脲酶微生物诱导矿化的胶结作用机理及影响因素。研究结果表明，MICP技术能有效加固软黏土，该反应在14d龄期左右可完成，经MICP加固后的软黏土抗压强度显著提高，渗透性明显降低，粘聚力显著增大，内摩擦角基本不变。本项目的研究结果可为微生物技术在软黏土地基处理领域内的工程应用提供参考。