摘要
采用一次浸泡菌液的方式,制备不同浓度(0、0.3、0.5、0.7 mol/L)营养盐处理的微生物诱导碳酸钙沉淀(MICP)胶结重塑泥岩样。基于直接剪切、碳酸钙酸洗法、扫描电镜(SEM)等试验测试胶结试样,分析了营养盐浓度对胶结试样力学性能、碳酸钙含量及微观结构的影响。结果表明:同等反应条件下(相同时间、体积),随着营养盐浓度的增加抗剪强度先增大后减小,当营养盐浓度达到0.5 mol/L时抗剪强度最大,此时,试样黏聚力、内摩擦角分别为15.5 kPa、18.83°;碳酸钙含量随着营养盐浓度的增加而增加,当营养盐浓度达到0.7 mol/L时,试样平均碳酸钙含量提高较少;碳酸钙晶体分布均匀性随着营养盐浓度由低到高变化呈凸字形态;胶结试样的强度依赖于生成的CaCO 3晶体量及其分布形态;生成的方解石型碳酸钙晶体主要沉积在颗粒接触处形成积聚晶体或填充在孔隙中形成“胶结桥”,产生胶结效果而增强试样的力学性能。
Microbial induced calcium carbonate precipitation(MICP)cemented remolded mudstone samples were prepared by injecting one-time bacteria solution with different concentrations(0,0.3,0.5,0.7 mol/L)of nutrient salt treatment.Based on the results of direct shear test,calcium carbonate pickling and scanning electron microscopy(SEM),the effects of nutrient concentration on the mechanical properties,calcium carbonate content and microstructure of the cemented samples were analyzed.The results show that under the same reaction conditions(same time,volume),the shear strength increase at first and then decrease with the increase of nutrient concentration.When the nutrient salt concentration reaches 0.5 mol/L,the shear strength reaches the largest value.At this time,the cohesive force and internal friction angle of the sample are 15.5 kPa and 18.83°,respectively.The content of calcium carbonate increase with nutrient concentration.When the concentration of nutrient salt reaches 0.7 mol/L,the average calcium carbonate content of the sample increases less.The uniformity of calcium carbonate crystal distribution changes in a convex shape with the increase of nutrient salt concentration from low to high.The strength of the cemented sample depends on the amount of CaCO 3 crystals formed and their distribution.The produced calcite-type calcium carbonate crystals are mainly deposited at the contact position of the particles to form accumulated crystals or filled in the pores to form a“bonding bridge”,which produces a cementation effect and enhances the mechanical properties of the sample.
作者
王绪民
崔芮
王铖
Wang Xumin;Cui Rui;Wang Cheng(School of Civil Engineering&Environment,Hubei University of Technology,Wuhan 430068,P.R.China)
出处
《土木与环境工程学报（中英文）》
CSCD
北大核心
2020年第4期76-83,共8页
Journal of Civil and Environmental Engineering
基金
湖北工业大学科研基金(BSQD14040)。
关键词
微生物诱导碳酸钙沉淀
重塑泥岩
物理力学指标
营养盐
微观结构
microbial induced calcium carbonate precipitation(MICP)
reshaping mudstone
physico-mechanical index
nutrient
micro structure
