微生物改性肥槽回填土试验

胡建伟; 陈学龙; 张衡; 刘昊东; 庞成立; 李登峰

doi:10.13205/j.hjgc.202403022

微生物改性肥槽回填土试验

doi: 10.13205/j.hjgc.202403022

1. 中冶武勘工程技术有限公司, 武汉 430080;
2. 长江大学, 湖北荆州 434000;
3. 中国五冶集团有限公司, 成都 610031

基金项目:

国家自然科学基金项目(51978545)

道路桥梁与结构工程湖北省重点实验室开放基金(DQJJ202109)

详细信息

作者简介:
胡建伟(1988-),男,高级工程师,主要研究方向为岩土工程设计、施工及地质灾害治理。411088120@qq.com

通讯作者:
胡建伟(1988-),男,高级工程师,主要研究方向为岩土工程设计、施工及地质灾害治理。411088120@qq.com

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出版历程
- 收稿日期: 2023-08-30
- 网络出版日期: 2024-05-31

EXPERIMENTAL STUDY ON BACKFILLING OF MICROBIAL MODIFIED FERTILIZER TANK

1. WSGRI Engineering and Surveying Incorporation Limited, Wuhan 430080, China;
2. School of Urban Construction, Jingzhou 434000, China;
3. China MCC5 Group Corp., Ltd., Chengdu 610031, China

摘要

摘要: 现代城市建设中,狭长且超深的基坑肥槽因作业空间受限回填质量普遍偏低,肥槽回填土后期易产生不均匀沉降、渗水以及抗浮等问题,亟待采取新型有效的措施提高肥槽回填质量。微生物诱导碳酸钙沉积(MICP)作为一种新型加固技术,可用于提高回填土强度并降低回填土渗透。为探究MICP技术应用于肥槽回填土的改性效果,以室内试验为先导,探讨2种改性方法在不同菌液细胞浓度、胶结干粉施加比例及胶结液浓度的配比下的改性效果,再将最佳配比的改性方法应用于实际工程验证。结果表明:2种改性方法中渗流法相较于拌制法胶结质量可控、改性效果更好。渗流法最优添加物配比为10倍稀释的菌液及低浓度0.5 mol/L∶0.5 mol/L(尿素与氯化钙浓度比例)的胶结液。现场验证试验改性后肥槽回填土相较于常规措施回填土,无侧限抗压强度提升174.2％~772.7％,压缩系数值减小0.09~0.41,孔隙比减小0.08~0.5,渗透系数降低1~4个数量级。改性后肥槽回填土对比常规措施回填土不均匀沉降基本消除,阻隔地下水渗流能力增强,回填质量显著提高。
- MICP /
- 土体改性 /
- 狭长深 /
- 肥槽回填土 /
- 回填质量
Abstract: In modern urban construction, deep and large foundation pits, and narrow and ultra-deep fertilizer tanks are becoming more and more common. Due to the limited working space, the backfill quality of such fertilizer tanks is generally low, resulting in uneven settlement, water seepage, and anti-floating problems of soil around the fertilizer tanks in the later stage. New and effective measures are urgently needed to improve the backfill quality of fertilizer tanks. Microbial induced calcium carbonate deposition (MICP), as a new reinforcement technique, can be used to improve the strength of backfill and reduce the permeability of backfill. In this paper, laboratory experiments were conducted to discuss the modification effect of the two modification methods under different cell concentrations of the bacterial solution, the proportion of cementing dry powder applied, and the proportion of cementing liquid concentration. Then, the modification method with the best ratio was applied to practical projects for verification. The results showed that, compared with the unmodified sample, the permeability coefficient of the mixing method was significantly reduced by 2 to 4 orders of magnitude. Both the seepage method and the mixing method can effectively improve the quality of the backfill. Compared with the mixing method, the seepage method had a better modification effect and controllable cementation quality. The optimal additive ratio of the percolation method was 10 times diluted bacterial solution and low concentration 0.5 mol/L∶0.5 mol/L (concentration ratio of urea to Call₂)of cemented solution. Field verification test showed that the unconfined compressive strength of the modified fertilizer tank backfill was increased by 174.2% to 772.7%, compared with the conventional measure. The compressibility coefficient of the modified fertilizer tank backfill was smaller than that of the conventional backfill, and the medium compressible soil became low compressible soil. The porosity ratio and permeability coefficient of modified fertilizer tank backfill were obviously lower than those of conventional backfill. After the test, the non-uniform settlement of the backfill in the fertilizer tank was basically eliminated, the ability to block groundwater seepage was enhanced, and the quality of the backfill was significantly improved.
- MICP /
- soil modification /
- narrow, long and deep /
- backfilling soil in foundation trench /
- backfill quality

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参考文献(17)

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