摘要
目前在研究影响微生物胶结土体时,着重于研究加固方法及影响加固效果的因素,缺少对养护条件以及处理后试样耐久性的探讨。本文以海相吹填粉土为处理对象,选用巴氏芽孢杆菌为试验用菌,采用两阶段注浆的方法进行加固,研究不同养护温度、冻融循环以及干湿循环对加固效果的影响。试验结果表明:(1)采用注浆方法可以有效对该粉土进行胶结加固。在排除水分的影响后,高、低温养护温度对试样的无侧限抗压强度以及CaCO_(3)生成百分比均无明显影响;(2)冻融循环对试样无侧限抗压强度的削弱主要发生在第1次冻融循环中,然后随着冻融循环次数的增加,试样的加固效果无明显变化。冻融循环后的试样烘干后,其无侧限抗压强度有明显提高,但仍低于未经冻融循环的试样;(3)干湿循环次数对试样强度的影响较小。烘干试样和饱和试样的强度有较大差别,说明试样的含水状态对强度有明显影响。因此在进行强度试验前,应明确试样的含水状态以便于评价加固效果。
The current studies on soil improvement by microbial cementation focus on treatment methods and various variables that have influence on the reinforcement effect. Nevertheless,there are a lack of research on curing condition and durability of treated samples. In this study,the microbial cementation was applied to treat marine silt,and Bacillus pasteurus was selected as the microorganism.The two-phase injection method was adopted to reinforce the samples and the influence of curing tem-perature,freeze-thaw cycles and wet-dry cycles on reinforcement effect was studied. The following results are derived from the experiments:(1) The silt could be cemented with the applied injection method. After eliminating the interference of water,high and low temperatures have no significant effect on the unconfined compressive strength of the sample and the overall percentage of CaCO_(3).(2)The decline of the unconfined compressive strength by the freeze-thaw cycles mainly occurs in the first freeze-thaw cycle,afterwards with the increased number of freeze-thaw cycles,the reinforcement effect of the sample has no significant variation. The strength of the samples experienced freeze-thaw cycles has a significant increase when the samples are dried but still lower than samples without freezethaw cycles.(3)The wet-dry cycles have little effect on the strength of treated samples. Significant strength variation exists in dry and saturated samples,which suggests the water condition of sample has dramatic impact on reinforcement effect. Therefore,the water condition should be specified before strength testing for the purpose of effect evaluation.
作者
曹晨
赵志峰
王玮
CAO Chen;ZHAO Zhifeng;WANG Wei(College of civil engineering,Nanjing Forestry University,Nanjing 210037,China)
出处
《防灾减灾工程学报》
CSCD
北大核心
2022年第5期1046-1052,共7页
Journal of Disaster Prevention and Mitigation Engineering
基金
国家自然科学基金面上项目(51578293)
江苏省高校自然科学基金(15KJB580008)资助。
关键词
微生物胶结
海相粉土
养护温度
冻融循环
microbial cementation
marine silt
curing temperature
freeze-thaw cycle
