外掺剂联合MICP固化风积沙试验研究  

Experimental study on curing eolian sand by additive combined with MICP

作　　者：刘小军[1,2] 柳子康 方玉 朱芮 Liu Xiaojun;Liu Zikang;Fang Yu;Zhu Rui(College of Civil Engineering,Xi'an University of Architecture and Technology,Xi'an,Shaanxi 710055;Key Laboratory of Geotechnical and Underground Space Engineering of Shaanxi Province,Xi'an,Shaanxi 710055)

机构地区：[1]西安建筑科技大学土木工程学院,陕西西安710055 [2]陕西省岩土与地下空间工程重点实验室,陕西西安710055

出　　处：《资源环境与工程》2024年第4期463-471,共9页Resources Environment & Engineering

摘　　要：微生物诱导碳酸钙沉淀技术(MICP)结合纤维加筋或外加剂已成为岩土体改良的新型方式,在土地荒漠化治理等场景具有广阔的应用前景。以取自毛乌素沙漠的风积沙为研究对象,在MICP联合纤维加筋的基础上,分别引入料姜石和氧化钙,使得两种无机化合物对微生物过程及加固效果产生影响,在最优养护条件下进行风积沙的固化试验,通过无侧限抗压强度试验、三轴试验、扫描电镜试验等,从宏观、微观角度系统分析外掺剂参与固化后试样的力学特性、破坏形态及作用机理。结果表明,MICP纤维加筋试样的强度随料姜石掺量的增加呈现增大趋势,并在掺量为4%时达到峰值,较未掺入料姜石试样的强度提高了37.3%;MICP纤维加筋试样的强度随氧化钙掺量的增加呈现先减小后增大的趋势,并在掺量达到1%时强度下降了74.6%;氧化钙对细菌具有明显的抑制作用,当氧化钙掺量达到0.8%时,大部分细菌已失去活性,OD_(600)值降至最低,为0.107;料姜石对MICP纤维加筋固化效果的作用机理主要表现在料姜石可有效地黏结砂土颗粒和填充孔隙,从而提高试样的整体稳定性。研究成果可为风积沙固化实践和实际工程应用提供参考依据。Microbially induced calcium carbonate precipitation technology(MICP)combined with fiber reinforcement or additive has become a new way of rock and soil improvement,and has broad application prospects in scenarios such as land desertification control.This paper takes the eolian sand taken from the Mu Us Desert as the research object,and introduces ginger stone and calcium oxide on the basis of MICP combined with fiber reinforcement,so that the two inorganic compounds have an impact on the microbial process and reinforcement effect.The mechanical properties,failure modes and mechanism of the samples after curing with the participation of additive were systematically analyzed from a microscopic perspective.The test results show that the strength of the MICP combined fiber reinforcement solidified specimen shows an increasing trend with the increase of the amount of ginger stone incorporated,and reaches the peak when the content is 4%,which is 37.3% higher than that of the non-incorporated ginger stone specimen.The strength of the solidified specimens with MICP combined fiber reinforcement showed a trend of first decreasing and then increasing with the addition of calcium oxide,and the strength decreased by 76.4% when the content reached 1%.Calcium oxide has a significant inhibitory effect on bacteria,when the calcium oxide content reaches 0.8%,most of the bacteria have lost their activity,and the OD 600 value is the lowest,which is 0.107.The mechanism of action of ginger stone on the solidification effect of MICP combined fiber reinforcement is mainly manifested in the fact that ginger stone can effectively eolian sand particles and fill pores,so as to improve the overall stability of the specimen.The research results can provide reference for the practice of eolian sand solidification and practical engineering application.

关 键 词：MICP 风积沙 无机材料 力学特性 微观分析 

分 类 号：TU441[建筑科学—岩土工程]