改良微生物诱导碳酸钙沉淀技术加固粉性土力学性能  

Mechanical Properties of Soil Strengthened by Improved Microbially Induced Calcite Precipitation Technology

作　　者：岳建伟[1] 张宝玺 赵丽敏[1] 孔庆梅[1] 王思远 YUE Jian-wei;ZHANG Bao-xi;ZHAO Li-min;KONG Qing-mei;WANG Si-yuan(School of Civil Engineering and Architecture, Henan University, Kaifeng 475004, China;Puyang Urban Development Investment Group Co., Ltd., Puyang 457000, China)

机构地区：[1]河南大学土木建筑学院,开封475004 [2]濮阳城市发展投资集团有限公司,濮阳457000

出　　处：《科学技术与工程》2021年第18期7702-7710,共9页Science Technology and Engineering

基　　金：河南大学一流学科培育项目(科技)(2019YLZDCG05);河南省科技发展计划项目(162300410012)。

摘　　要：微生物诱导碳酸钙沉淀技术(microbially induced calcite precipitation,MICP),是近年来在国内兴起的一项多学科交叉的技术,工程技术人员将它引入到土木工程中,使得土体各项性能得以改良;黄河中下游的粉性土水稳定性差,毛细水作用大,干燥时强度高但潮湿时强度显著下降,利用MICP技术加固粉性土值得研究。以粉性土为研究对象,首先研究了不同糯米浆浓度下土样的力学性能,以最优糯米浆浓度作为改良材料对MICP技术进行改良;其次控制胶菌质量比为2∶1,研究了不同胶结液浓度下MICP技术的产碳酸钙量以及Ca2+转化率,得出MICP技术的最佳配比,结合最优糯米浆浓度形成改良MICP技术;最后研究了素土、MICP加固土、改良MICP加固土土样养护7 d后的力学性能。研究表明:土样最优糯米浆浓度为3%,此时土体无侧限抗压强度与内摩擦角达到最大;MICP技术最佳配比为2∶1胶菌质量比、0.5 mol/L胶结液浓度,此时产碳酸钙量最多且Ca2+转化率在80%以上,添加3%糯米浆浓度的改良MICP技术Ca^(2+)转化率在90%以上,比MICP技术高10%;通过土的直接快剪试验和无侧限抗压强度试验,MICP加固土的黏聚力提高了约30%,内摩擦角变化不大,改良MICP加固土的黏聚力提高了约50%,内摩擦角提高了约17%。Microbial induced microbially induced calcite precipitation(MICP)is called MICP.In recent years,MICP technology is a multi-disciplinary interdisciplinary technology rising in China,which is introduced into civil engineering by engineers and technicians,so that the mechanical properties of soil can be strengthened.Silty soil was taken as the research object.Firstly,the mechanical properties of soil samples with different concentrations of glutinous rice slurry were studied.The optimal concentration of glutinous rice pulp was used as the improvement material to improve the MICP technology.Secondly,the production of calcium carbonate and the conversion rate of Ca2+were studied by controlling the mass ratio of glue bacteria to be 2∶1.The optimal ratio of MICP technology was obtained.Combined with the optimal concentration of glutinous rice pulp,the improved MICP technology was formed.Finally,the mechanical properties of plain soil,MICP reinforced soil and modified MICP reinforced soil after curing for 7 days were studied.The results show as follows.When the optimal concentration of glutinous rice slurry is 3%,the unconfined compressive strength and internal friction angle of soil reach the maximum.The optimal ratio of MICP technology is 2∶1,the mass ratio of gum to bacteria and the concentration of 0.5 mol/L cementation solution.At this time,the production of calcium carbonate is the most and the conversion rate of Ca^(2+)is more than 80%.The conversion rate of Ca2+of modified MICP technology with 3%glutinous rice pulp concentration is more than 90%,which is 10%higher than that of MICP technology.Through the direct fast shear test and unconfined compressive strength test,the cohesion of the soil strengthened by MICP is increased by about 30%,and the internal friction angle changes little.The cohesion of the soil strengthened by modified MICP is increased by about 50%,and the internal friction angle is increased by about 17%.

关 键 词：改良MICP技术 糯米浆 黏聚力 内摩擦角 无侧限抗压强度 

分 类 号：TU375.4[建筑科学—结构工程]