Impact of mica on geotechnical behavior of weathered granitic soil using macro and micro investigations  

作　　者：Xianwei Zhang Xinyu Liu Haodong Gao Gang Wang Ran An Zhu Liang 

机构地区：[1]State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,430071,China [2]School of Civil and Hydraulic Engineering,Huazhong University of Science and Technology,Wuhan,430074,China [3]College of Urban Construction,Wuhan University of Science and Technology,Wuhan,430065,China [4]University of Chinese Academy of Sciences,Beijing,100049,China [5]Guangzhou Urban Planning&Design Survey Research Institute,Guangzhou,510000,China [6]Guangdong Enterprise Key Laboratory for Urban Sensing,Monitoring and Early Warning,Guangzhou,510000,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2024年第6期2250-2266,共17页岩石力学与岩土工程学报（英文版）

基　　金：The financial supports of the National Natural Science Foundation of China(Grant No.42177148);the opening fund of State Key Laboratory of Geohazard Prevention and Geo-environment Protection(Grant No.SKLGP 2023K011);Postdoctoral Research Project of Guangzhou(Grant No.20220402)are gratefully thanked.

摘　　要：The micaceous weathered granitic soil(WGS)is frequently encountered in civil engineering worldwide,unfortunately little information is available regarding how mica affects the physico-mechanical behaviors of WGS.This study prepares reconstituted WGS with different mica contents by removing natural mica in theWGS,and then mixes it with commercial mica powders.The geotechnical behavior as well as the microstructures of the mixtures are characterized.The addition of mica enables the physical indices of WGS to be specific combinations of coarser gradation and high permeability but high Atterberg limits.However,high mica content in WGS was found to be associated with undesirable mechanical properties,including increased compressibility,disintegration,and swelling potential,as well as poor compactability and low effective frictional angle.Microstructural analysis indicates that the influence of mica on the responses of mixtures originates from the intrinsic nature of mica as well as the particle packing being formed withinWGS.Mica exists in the mixture as stacks of plates that form a spongy structure with high compressibility and swelling potential.Pores among the plates give the soil high water retention and high Atterberg limits.Large pores are also generated by soil particles with bridging packing,which enhances the permeability and water-soil interactions upon immersion.This study provides a microlevel understanding of how mica dominates the behavior of WGS and provides new insights into the effective stabilization and improvement of micaceous soils.

关 键 词：Weathered granitic soil(WGS) MICA Microstructure Physical properties Mechanical properties Mechanism 

分 类 号：TU41[建筑科学—岩土工程]