摘要
高速铁路不可避免地穿越工程性质较差的红层泥岩地区,采用自主提取的蜡样芽孢杆菌进行微生物诱导碳酸盐沉积(Microbial induced carbonate precipitation, MICP)技术增强水泥改良红层泥岩路基填料的性能,通过比较MICP技术改良前后试样的物理力学指标,分析其改良效果;结合微观结构测试结果,探究红层泥岩填料的水泥-微生物协同改良机制。与单一水泥改良组相比,水泥-微生物改良组的无侧限抗压强度提高了12.31%~14.25%、渗透系数降低了6.06%~34.06%、无荷载膨胀率降至0.52%~0.65%,表明微生物的掺加对水泥改良土试样的力学强度、抗渗性和抗膨胀性均有明显提升作用。水泥水化反应和微生物矿化反应同时进行、相互促进,在二者共同作用下,生成了更多的碳酸钙晶体及水化硅酸钙(C-S-H)凝胶等胶结物质填充土颗粒间孔隙并胶结相邻的土颗粒,使得填充后试样的孔隙尺寸及数量均减小,同时增加了颗粒间的接触位点,使得相邻颗粒间胶结得更为紧密,进而改善试样内部孔隙结构、增强颗粒间胶结性能,从而提升红层泥岩填料的物理力学性能。预期研究成果可为微生物增强水泥土技术的工程应用提供参考。
The high-speed railway inevitably passes through the areas with red mudstone layer,which is of poor engineering properties.A study was conducted on microbial induced carbonate precipitation(MICP)technique to enhance the performance of red mudstone roadbed filler by using self-extracted Bacillus cereus.By comparing the physical and mechanical indicators of the samples before and after improvement using MICP technique,the enhancement effect was analyzed,and the synergistic enhancement mechanism of cement and MICP was explored from a microstructure perspective.The results showed that,compared with the cement modified soil samples,the unconfined compressive strength of the cement-microbial modified soil samples increased by 12.31%—14.25%,the permeability coefficient decreased by 6.06%—34.06%,and the unloaded expansion rate decreased to 0.52%—0.65%.The addition of microorganisms significantly improves the mechanical strength,impermeability,and expansion resistance of cement modified soil samples.Cement hydration reaction and microbial mineralization reaction are carried out simultaneously and promote each other.Under the combined effects of both,more calcium carbonate crystals and hydrated calcium silicate(C-S-H)gel and other cementitious substances are generated to fill the pores between soil particles and cement adjacent soil particles,minimizing the pore size,reducing the number of filled pores,and increasing the contact points between particles.In this way,the adjacent particles are cemented more closely,thereby improving the internal pore structure of the sample,enhancing the cementation performance between particles,and thus improving the physical and mechanical properties of red mudstone filler.The expected research results can provide reference for the engineering application of microbial enhanced cement soil technology.
作者
肖瑶
邓华锋
程雷
黄小芸
李建林
XIAO Yao;DENG Huafeng;CHENG Lei;HUANG Xiaoyun;LI Jianlin(Key Laboratory of Geological Hazards on Three Gorges Reservoir Area of Ministry of Education,China Three Gorges University,Yichang 443002,Hubei,China)
出处
《材料导报》
北大核心
2025年第15期100-107,共8页
Materials Reports
基金
国家自然科学基金(U22A20600,U2034203)
三峡大学人才科研启动基金项目(2024RCKJ021)。
关键词
微生物诱导碳酸盐沉积
红层泥岩填料
力学特性
抗膨胀性
增强机理
microbially induced carbonate precipitation(MICP)
red mudstone filler
mechanical property
expansion resistance
enhancement mechanism
