微生物加固钙质砂环剪试验研究  

Experimental study on microbial reinforced calcareous sand using ring shear apparatus

作　　者：丁绚晨 陈育民[1] 张鑫磊 DING Xuan-chen;CHEN Yu-min;ZHANG Xin-lei(Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,College of Civil and Transportation Engineering,Hohai University,Nanjing 210098,China)

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点实验室,土木与交通学院,江苏南京210098

出　　处：《浙江大学学报（工学版）》2020年第9期1690-1696,1735,共8页Journal of Zhejiang University：Engineering Science

基　　金：国家自然科学基金资助项目(41831282,51679072);中央高校基本科研业务费专项资金资助项目(2018B43214).

摘　　要：对取自南海岛礁的钙质砂进行固化处理,通过环剪试验研究微生物诱导碳酸钙沉积(MICP)胶结钙质砂的抗剪强度特性,并考虑菌液浓度、菌液浸泡时间、加固液浓度、加固时间、竖向应力以及海水环境等因素的影响.结果表明:MICP方法可以有效提高钙质砂的抗剪强度.当加固液浓度为0.5 mol/L时,加固后试样的抗剪强度达到最大值,约为未加固试样的3倍,并表现出显著的应变软化现象.提高菌液浓度、菌液浸泡时间、加固液浓度、加固时间均可改善微生物加固效果,减小残余强度与峰值强度的比值,使试样的应变软化现象越来越明显.海水环境虽对MICP加固过程有抑制作用,但在此环境下采用MICP方法仍能有效提升钙质砂地基的抗剪强度.The calcareous sand reinforced in this experiment was obtained from an island in the South China Sea.The shear strength characteristics of microbially induced carbonate precipitation(MICP)cemented calcareous sand were studied using ring shear tests.The influences of bacterial concentration,immersion time of bacterial solution,cementation solution concentration,treated time,vertical stress and seawater environment were considered.Results show that MICP can effectively improve the shear strength of calcareous sand.When the cementation solution concentration was 0.5 mol/L,the shear strength of the treated samples reached the maximum values,which was about three times of that of the untreated samples,showing a remarkable strain softening phenomenon.Increasing the concentration of the bacteria solution,soaking time,concentration of the reinforcement solution and strengthening time can improve the reinforcement effect,reduce the ratio of residual strength to peak strength,and make the strain softening phenomenon more and more obvious.Although seawater has an inhibitory effect on the reinforcement process of MICP,the application of MICP in this environment can effectively improve the shear strength of calcareous sandy foundation.

关 键 词：微生物加固 钙质砂 环剪试验 抗剪强度 残余强度 

分 类 号：TU433[建筑科学—岩土工程]