靶向激活产脲酶微生物联合酶诱导碳酸盐沉淀加固陆域吹填海砂试验研究  

Experimental study on solidification of land reclamation sea sand by EICP combined with targeting activation of microbes producing urease

作　　者：曹光辉 刘士雨[1] 蔡燕燕[1] 俞缙[1] 孙志龙 CAO Guang-hui;LIU Shi-yu;CAI Yan-yan;YU Jin;SUN Zhi-long(Fujian Research Center for Tunneling and Urban Underground Space Engineering,Huaqiao University,Xiamen,Fujian 361021,China;China Railway Nanchang Group Co.,Ltd.,Nanchang,Jiangxi 330002,China)

机构地区：[1]华侨大学福建省隧道与城市地下空间工程技术研究中心,福建厦门361021 [2]中国铁路南昌局集团公司,江西南昌330002

出　　处：《岩土力学》2022年第8期2241-2252,共12页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.52178334,No.51978292);福建省自然科学基金(No.2019J01048)。

摘　　要：生物矿化加固土体方式目前呈现多样化,不同矿化方式又有其各自的局限性,酶诱导碳酸盐沉淀(EICP)缺乏成核位点,而靶向激活产脲酶微生物诱导矿化(生物刺激)加固周期较长、强度较低。针对这些问题,提出生物刺激联合EICP加固土体的矿化方法。以厦门翔安国际机场吹填海砂为试验对象,通过无侧限抗压强度测试(UCS)、碳酸钙生成量测定、扫描电子显微镜(SEM)、X射线衍射(XRD)和微生物多样性检测等试验评价并分析联合方法的加固效果。结果表明:(1)生物刺激联合EICP的矿化方式得到更高的UCS,可以达到2300 kPa,大于两者单独矿化的强度之和;(2)生物刺激联合EICP的矿化方式可以促进碳酸钙沉淀生成的同时提高其分布均匀性,并优化碳酸钙的晶体结构;(3)微生物的群落分析表明,生物刺激可以高度激活产脲酶细菌,EICP对部分物种有轻微的刺激作用,生物刺激联合EICP的物种丰富程度、均匀程度则介于EICP和生物刺激之间。Biomineralization of soil solidification methods is currently diversified,and different mineralization methods have their own limitations.The enzyme-induced carbonate precipitation(EICP)lacks nucleation sites,while the targeted activation of urease-producing microorganisms induced mineralization(biostimulation)has a longer solidification cycle and lower strength.Aiming at these problems,a mineralization method of biostimulation combined with EICP to reinforce soil is developed.In this paper,reclaimed sea sand from Xiamen Xiang’an International Airport was investigated.Unconfined compressive strength tests(UCS),calcium carbonate production measurements,scanning electron microscope(SEM),X-ray diffraction(XRD),and microbial diversity testing were used to evaluate and analyze the solidification effect of the combined method.Some findings were observed.1)Biostimulation combined with EICP mineralization can get a higher UCS,up to 2300 kPa,which was greater than the sum of the UCS of the two separate mineralizations.2)Biostimulation combined with EICP can promote the formation of calcium carbonate precipitation while improving its distribution uniformity,and optimize the crystal structure of calcium carbonate.3)Microbial community analysis shows that biostimulation can highly stimulate urease-producing bacteria.EICP has a slight stimulating effect on some species.The species richness and uniformity of biostimulation combined with EICP are between those of EICP and biostimulation.

关 键 词：靶向激活 酶诱导碳酸盐沉淀(EICP) 吹填海砂 加固 微生物群落 

分 类 号：TU431[建筑科学—岩土工程]