摘要
因土体孔隙小,目前微生物矿化技术(MICP)在铝尾黏土固化中鲜有应用。基于尾矿库复垦需求,采用生石灰与微生物共同固化技术(生化固化技术)对过湿性铝尾黏土进行处理并与石灰固化技术处理进行对比,通过SEM扫描、压汞试验、剪切试验和压缩性试验揭示其生成物元素组成、土体微观结构和强度变化规律。试验结果表明:生石灰与土中水发生水化反应,形成大量较大直径孔隙,为微生物生存提供空间;生石灰与铝尾黏土中水反应生成Ca(OH)2导致土体pH值和温度升高,试验生石灰掺入量导致的土体温度上升处于试验菌种耐受范围内,同时该菌种具有较好耐碱性,能够利用生石灰水解产生的Ca^2+进行矿化作用,但过高碱性会影响其代谢,故应控制生石灰掺量;石灰固化技术处理铝尾黏土能够提升土的抗剪强度,降低压缩系数;生化固化技术处理铝尾黏土能有效填充土体孔隙和黏结土颗粒,处理效果优于生石灰固化技术处理,考虑生化固化效果的最优生石灰掺入量为23.33 kg/m^3。
Because the pores of bauxite tailing clay are small,the microbial induced calcite precipitation(MICP)is rarely used in this research area at present.Based on the reclamation requirements of tailings pond,the quicklime and microbial co-curing technology(biochemical curing technology)is given to treat the super-wet bauxite tailing soil,and the results are compared with those by the lime curing treatment.Through SEM scanning,mercury injection tests,shear tests and compressibility tests,the change rules of element composition and microstructure and strength are revealed.The results show that numerous large pores are formatted by the hydration reaction between the quicklime and the water,which provides space for the survival of microorganisms.Ca(OH)2 is generated by the reaction of quicklime and water in the bauxite tailings soil so as to increase the pH value and temperature.The soil temperature rise caused by the addition of quicklime is within the allowable range of the test strains.The sporosarcina pasteurii used in the experiment is alkali-resistant and can mineralize with Ca^+ produced by the hydrolysis of quicklime.However,high alkalinity will affect the metabolism,and the content of quicklime should be controlled.The shear strength of the soil is improved and the compressibility is reduced after treated by the quicklime.The soil can be filled and bonded effectively by the biochemical curing,and the effect is better than that by the quicklime.The optimal amount of the quicklime in biochemical curing is 23.33 kg/m^3.
作者
欧孝夺
莫鹏
江杰
苏建
彭远胜
OU Xiao-duo;MO Peng;JIANG Jie;SU Jian;PENG Yuan-sheng(College of Civil Engineering and Architecture,Guangxi University,Nanning 530004,China;Security Key Laboratory of Disaster Prevention and Structural Engineering,Nanning 530004,China;Guangxi Engineering Research Center for Metallic Tailings Security Prevention and Control,Nanning 530004,China;Guangxi Bossco Environmental Protection Technology Co.,Ltd.,Nanning 530004,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2020年第4期624-631,共8页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金地区科学基金项目(51768006,51568006)
广西科技计划项目(桂科AB17195035)。
关键词
生化固化
微生物
生石灰
铝尾黏土
biochemical solidification
microorganism
quicklime
bauxite tailings clay
