Study on the microscopic mechanism of the loess improved by quicklime

Authors

XIE Xiao, Institute of Land Engineering and Technology, Shaanxi Provincial Land Engineering Construction Group Co., Ltd., Xi'an 710075, China; Key Laboratory of Degraded and Unused Land Consolidation Engineering, Ministry of Natural Resources, Xi'an 710075, China; Shaanxi Provincial Land Consolidation Engineering Technology Research Center, Xi'an 710075, China
WANG Luyao, Institute of Land Engineering and Technology, Shaanxi Provincial Land Engineering Construction Group Co., Ltd., Xi'an 710075, China; Key Laboratory of Degraded and Unused Land Consolidation Engineering, Ministry of Natural Resources, Xi'an 710075, China; Shaanxi Provincial Land Consolidation Engineering Technology Research Center, Xi'an 710075, China
DENG Lejuan, Xi'an Geological Environmental Monitoring Station, Xi'an 710068, China
ZHANG Guowei, China Coal Xi'an Design Engineering Co., Ltd., Xi'an 710054, China

Abstract

To investigate the influence of lime content on loess strength and its microscopic mechanism, different proportions of lime were used to improve loess. Through direct shear test, mercury intrusion porosimetry and scanning electron microscopy, the strength characteristics and microstructure changes of compacted loess and modified loess with different lime contents were analyzed qualitatively and quantitatively, and the microscopic mechanism of lime-improved loess was analyzed in depth. The results show that the shear strength parameters of lime-improved loess increases first and then decreases with the increase of lime contents. The cohesive force and internal friction angle reach the maximum when the lime content is about 8%. The incorporation of lime gradually increases the cements between and on the surface of the skeleton particles. As the pores are filled with cements, the unstable pores gradually decrease, and the integrity is enhanced. But with too large lime content, the excess lime will accumulate between the agglomerates, which will affect the cementation. The reason for the increasing strength of lime-improved loess is that the cementing material generated by the lime hydration reaction enhances the degree of cementation between soil particles, resulting in a larger friction between the particles, a more stable soil structure, and greater soil strength. However, the excessive lime will reduce the cementation between soil particles, thus reducing the shear strength of the improved loess. The research results not only enrich the theoretical research on the strength characteristics and microstructure of loess, but also provide reference for the selection of engineering design parameters of improved loess.

Keywords

loess, quicklime, microstructure, shear strength

DOI

10.3969/j.issn.1001-1986.2021.06.023

Recommended Citation

XIE Xiao, WANG Luyao, DENG Lejuan, et al. (2021) "Study on the microscopic mechanism of the loess improved by quicklime," Coal Geology & Exploration: Vol. 49: Iss. 6, Article 24.
DOI: 10.3969/j.issn.1001-1986.2021.06.023
Available at: https://cge.researchcommons.org/journal/vol49/iss6/24

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