Effect of dry–wet cycles on the mechanical properties and microscopic characteristics of fine breccia soil from karst areas  

作　　者：Xin LI Hanqing CHEN Dong SU Xiangsheng CHEN Xiang SHEN 

机构地区：[1]Underground Polis Academy,College of Civil and Transportation Engineering,Shenzhen University,Shenzhen 518060,China [2]Key Laboratory of Coastal Urban Resilient Infrastructures(Shenzhen University),Ministry of Education,Shenzhen 518060,China [3]Shenzhen Key Laboratory of Green,Efficient,and Intelligent Construction of Underground Metro Station,Shenzhen 518060,China

出　　处：《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》2024年第12期974-990,共17页浙江大学学报(英文版)A辑(应用物理与工程)

基　　金：supported by the National Natural Science Foundation of China(Nos.52108377 and 51938008);the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515010060),China.

摘　　要：The quality of the railway subgrade is directly related to the fill soil structure,which,in turn,is determined by the local physical and chemical environment.A karst environment,with its frequent rainfall,promotes the dissolution of soluble rocks and underground transportation of solutes,altering the soil structure and performance.To investigate these alterations,we analyzed the properties of underground soil from highly developed karst areas.Fine breccia soil from karst regions was tested to assess its macroscopic mechanical properties and microstructural features,for differing initial water contents and compaction levels.Samples were subjected to simulated rainfall conditions through dry–wet cycles,and then underwent triaxial shear and electron microscopy tests.From these data,a micro-to-macro correlation model and a normalization model were developed.The findings suggest that the resistance of fine angular breccia soil to degradation during dry–wet cycles can be enhanced through high-pressure compaction and by maintaining a moisture content close to 15.6%.Increasing the degree of compaction improves the particle size distribution and the density of the soil skeleton.This is advantageous for minimizing soil particle erosion,thereby ensuring the strong performance of railway subgrades in karst areas with frequent rainfall.

关 键 词：Karst area Micro-macro properties Railway subgrade performance Dry-wet cycles 

分 类 号：S15[农业科学—土壤学]