Micro-experiment on MICP-treated Aeolian sandy soil under ultraviolet erosion environment
GAO Yu1,2, YAO De1, HAN Hong-wei2, LI Chi2
1. Chemical Engineering Institute, Inner Mongolia University of Technology, Hohhot 010051, China; 2. Civil Engineering Institute, Inner Mongolia University of Technology, Hohhot 010051, China
Abstract:Based on the MICP technology and the aeolian sandy soil of Ulan Buh desert as geotechnical substrate materials, the ultraviolet erosion characteristics of mineralization aeolian sandy soil induced by MICP are studied. In addition, the total effective time of outdoor ultraviolet irradiation in winter in Ulan Buh desert area is equal to the total effective time of indoor ultraviolet irradiation, and the ultraviolet irradiation time of indoor UV-erosion tests is determined. Through the scanning electron microscopyand nuclear magnetic resonance technology, the pore characteristics of the mineralization samples are analyzed with the irradiation period under the same ultraviolet radiation intensity. The results show that after UV-erosion, the microscopic electron microscope scanning indicates the that the MICP-mineralized specimen has pores in the calcium carbonate crystal under the ultraviolet erosion for a long time, which proves that the long-term irradiation erosion of ultraviolet weakens the property of calcium carbonate. When the ultraviolet erosion time is 1046 h, the porosity rate of MICP-mineralized aeolian sandy soil is 23.6%. In the nuclear magnetic resonance (NMR) tests, the T2 spectra of the specimens before ultraviolet erosion have multiple peaks and the pore distribution is uneven. The porosity of the specimen increases with the increase of irradiation time. With the increase of irradiation time, the pores are developed and expanded constantly, the large pores were decrease and the medium-sized pores increase. However, the small pores gradually develop and connect with the medium-sized ones, although there are residual macropores, most of them are converted into medium-sized ones, and the ultraviolet erosion resistance of mineralization materials gradually decreases. The pores of the three specimens are mostly distributed in the range of 0.1~8 μm, and the radius of small pores is mainly 1 μm. The study of ultraviolet erosionof bio-mineralization Aeolian sandy soil in the laboratory may provide a basic researchand favorable experimental basis for the application of this technique in the in-situ microbial crust of desert.
高瑜, 姚德, 韩宏伟, 李驰. 微生物诱导矿化风沙土的紫外侵蚀微观试验研究[J]. 岩土工程学报, 2020, 42(S1): 254-258.
GAO Yu, YAO De, HAN Hong-wei, LI Chi. Micro-experiment on MICP-treated Aeolian sandy soil under ultraviolet erosion environment. Chinese J. Geot. Eng., 2020, 42(S1): 254-258.
[1] CHU J, STABNIKOV V, IVANOV V.Microbially induced calcium carbonate precipitation on surface or in the bulk of soil[J]. Geomicrobiology Journal, 2012, 29(6): 544-549. [2] DEJONY JT, FRITAGES MB, NUSSLEIN K.Microbially induced cementation to control sand response to undrained shear[J]. Journal of Geotechnical and Eoenvironmental Engineering, 2006, 132(11): 1381-1392. [3] 李驰, 刘世慧, 周团结, 等. 微生物矿化风沙土强度及孔隙特性的试验研究[J]. 力学与实践, 2017, 39(2): 165-171, 184. (LI Chi, LIU Shi-hui, ZHOU Tuan-jie, et al.A study on strength and porosity properties for MICP-treated Aeolian sandy soil[J]. Mechanics and Practice, 2017, 39(2): 165-171, 184. (in Chinese)) [4] LI Chi DE Yao, LIU Shi-hui, et al. Improvement of geomechanical properties of bio-remediated Aeolian sand[J]. Geomicro Biology Journal, 2017, 35(2): 132-140. [5] 高瑜, 姚德, 秦骁, 等. 盐蚀环境下微生物矿化岩土材料的冻融特性研究[J]. 防灾减灾工程学报, 2018, 38(5): 787-794. (GAO Yu, YAO De, QIN Xiao, et al.Study on freeze-thaw properties for microbial materials in salt corrosion environment[J]. Journal of Disaster Prevention and Mitigation Engineering, 2018, 38(5): 787-794. (in Chinese)) [6] 李驰, 王硕, 王燕星, 等. 沙漠微生物矿化覆膜及其稳定性的现场试验研究[J]. 岩土力学, 2019, 40(4): 1292-1298. (LI Chi, WANG Shuo, WANG Yan-xing, et al.Field experimental study on stability of bio-mineralization crust in the desert[J]. Rock and Soil Mechanics, 2019, 40(4): 1292-1298. (in Chinese)) [7] 谷新波, 王佳, 张军. 呼和浩特市紫外线照射强度变化特征及相关因子分析[J]. 内蒙古气象, 2007(2): 27-29. (GU Xin-bo, WANG Jia, ZHANG Jun.Variation characteristics and correlation factor analysis of ultraviolet radiation intensity in Hohhot[J]. Inner Mongolia Meteorology, 2007(2): 27-29. (in Chinese)) [8] 赵大勇. 基于灰色关联分析的沥青混合料紫外线老化影响因素研究[D]. 西安: 西安建筑科技大学, 2015: 24-27. (ZHAO Da-yong.The Influence Factors of Ultraviolet Aging of Asphalt Mixture Based on Grey Correlation Analysis[D]. Xi'an: Xi'an University of Architecture Technology, 2015: 24-27. (in Chinese)) [9] 梁止水, 吴智仁, 杨才千, 等. 砒砂岩固结体防水抗蚀及紫外耐久性能研究[J]. 人民黄河, 2016, 38(6): 46-48(54). (LIANG Zhi-shui, WU Zhi-ren, YANG Cai-qian. Experimental study on affecting factors about sorting effect of the improved sediment sorting device[J]. Yellow River.2016, 38(6): 46-48(54). (in Chinese)) [10] 毛耀顺. 中国气象年鉴2001[M]. 北京: 气象出版社, 2001. (MAO Yao-shun.China Meteorological Yearbook 2001[M]. Beijing: Meteorological Publishing House, 2001. (in Chinese))