铁道科学与工程学报2024，Vol.21Issue(6)：2305-2316,12.DOI:10.19713/j.cnki.43-1423/u.T20231272
考虑双孔结构影响的压实红黏土持水特性及数学模型研究
Experimental and theoretical study on the water retention characteristics of compacted red clay considering the influence of double-pore structure
摘要
Abstract
Red clay is commonly used as roadbed fill material for infrastructure construction such as railways and highways in southern China.It exhibits a distinct double-pore structure during the compaction process that impacts soil-water characteristics,roadbed strength,and stability,resulting in engineering problems such as poor compaction and water stability.This study focused on red clay soil samples collected from Guangxi Nanning-Zhanjiang expressway and then prepared at four compaction levels using static pressure method.The pore distribution and soil-water characteristics at various compaction levels were measured using low-field nuclear magnetic resonance,HYPROP,and chilled-mirror dew point techniques.The impact of large and small pores on the state of water storage was analyzed.Based on the experimental results,a boundary pore size division method and the occurrence form of pore water were proposed.The microscale water retention mechanism of compacted red clay was elucidated.Furthermore,the study constructed the small pore adsorption equation based on Dubinin-Astakhov adsorption theory and the large pore capillary equation based on the Kosugi model.Ultimately,a bimodal SWCC model was established to describe water retention for the entire suction range in soil with a double-pore structure,and the model was validated using experimental data from six types of red clay and two other soil types found in the literature,demonstrating strong agreement and wide applicability.The results show that increased compaction significantly alters the distribution of large pores in the double-pore structure and decreases the proportion of liquid water in large pores,while small pores are mostly unaffected,resulting in variations in the low suction range of the soil-water characteristic curve.The SWCC model with definite physical meaning parameters provides valuable guidance for roadbed water migration calculation and deformation prediction.关键词
非饱和红黏土/双孔结构/孔隙分布曲线/土水特征曲线Key words
unsaturated red clay/double-pore structure/pore distribution curve/soil water characteristic curve分类
建筑与水利引用本文复制引用
冯学茂,谢治,陈成华,滕继东,徐光黎,魏海峰,耿成宝..考虑双孔结构影响的压实红黏土持水特性及数学模型研究[J].铁道科学与工程学报,2024,21(6):2305-2316,12.基金项目
国家自然科学基金资助项目(52178376) （52178376）
湖南省杰出青年基金资助项目(2022JJ10076) （2022JJ10076）
湖南省湖湘青年英才项目(2020RC3008) （2020RC3008）
东北边境穆棱—兴凯湖地区综合地质调查项目(中国地质调查局哈尔滨自然资源综合调查中心) （中国地质调查局哈尔滨自然资源综合调查中心）
中国中铁股份公司科技研究开发计划(2022-重大-13) （2022-重大-13）
