Characterization of unsaturated coarse-grained railway embankment fill: Water retention and dilatancy

This study investigated the hydraulic and mechanical behaviors of unsaturated coarse-grained railway embankment fill materials (CREFMs) using a novel unsaturated large-scale triaxial apparatus equipped with the axis translation technique (ATT). Comprehensive soil-water retention and constant-suction...

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Main Authors: Yuanjie Xiao, Wenqi Li, Liuxin Chen, Xiaoming Wang, Yunbo Li, Pan Tan, Jiapei Du
Format: Article
Language:English
Published: Elsevier 2025-05-01
Series:Journal of Rock Mechanics and Geotechnical Engineering
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Online Access:http://www.sciencedirect.com/science/article/pii/S1674775525001507
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author Yuanjie Xiao
Wenqi Li
Liuxin Chen
Xiaoming Wang
Yunbo Li
Pan Tan
Jiapei Du
author_facet Yuanjie Xiao
Wenqi Li
Liuxin Chen
Xiaoming Wang
Yunbo Li
Pan Tan
Jiapei Du
author_sort Yuanjie Xiao
collection DOAJ
description This study investigated the hydraulic and mechanical behaviors of unsaturated coarse-grained railway embankment fill materials (CREFMs) using a novel unsaturated large-scale triaxial apparatus equipped with the axis translation technique (ATT). Comprehensive soil-water retention and constant-suction triaxial compression tests were conducted to evaluate the effects of initial void ratio, matric suction, and confining pressure on the properties of CREFMs. Key findings reveal a primary suction range of 0–100 kPa characterized by hysteresis, which intensifies with decreasing density. Notably, the air entry value and residual suction are influenced by void ratio, with higher void ratios leading to decreased air entry values and residual suctions, underscoring the critical role of void ratio in hydraulic behavior. Additionally, the critical state line (CSL) in the bi-logarithmic space of void ratio and mean effective stress shifts towards higher void ratios with increasing matric suction, significantly affecting dilatancy and critical states. Furthermore, the study demonstrated that the mobilized friction angle and modulus properties depend on confining pressure and matric suction. A novel modified dilatancy equation was proposed, which enhances the predictability of CREFMs' responses under variable loading, particularly at high stress ratios defined by the deviatoric stress over the mean effective stress. This research advances the understanding of CREFMs' performance, especially under fluctuating environmental conditions that alter suction levels.
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institution Kabale University
issn 1674-7755
language English
publishDate 2025-05-01
publisher Elsevier
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series Journal of Rock Mechanics and Geotechnical Engineering
spelling doaj-art-0f96d5b9021d477da4b58cea6f2d7e792025-08-20T03:49:17ZengElsevierJournal of Rock Mechanics and Geotechnical Engineering1674-77552025-05-011753125314510.1016/j.jrmge.2025.03.016Characterization of unsaturated coarse-grained railway embankment fill: Water retention and dilatancyYuanjie Xiao0Wenqi Li1Liuxin Chen2Xiaoming Wang3Yunbo Li4Pan Tan5Jiapei Du6School of Civil Engineering, Central South University, Changsha, 410075, China; National Engineering Research Center of High-speed Railway Construction Technology, Changsha 410075, ChinaSchool of Civil Engineering, Central South University, Changsha, 410075, China; Corresponding author.ARC Industrial Transformation Research Hub (ITRH) – SPARC Hub, Dept. of Civil Engineering, Monash University, Clayton Campus, VIC, 3800, Australia; Corresponding author.School of Civil Engineering, Central South University, Changsha, 410075, ChinaSchool of Civil Engineering, Central South University, Changsha, 410075, ChinaSchool of Civil Engineering, Central South University, Changsha, 410075, ChinaSchool of Engineering, Royal Melbourne Institute of Technology, Melbourne, Victoria, 3001, AustraliaThis study investigated the hydraulic and mechanical behaviors of unsaturated coarse-grained railway embankment fill materials (CREFMs) using a novel unsaturated large-scale triaxial apparatus equipped with the axis translation technique (ATT). Comprehensive soil-water retention and constant-suction triaxial compression tests were conducted to evaluate the effects of initial void ratio, matric suction, and confining pressure on the properties of CREFMs. Key findings reveal a primary suction range of 0–100 kPa characterized by hysteresis, which intensifies with decreasing density. Notably, the air entry value and residual suction are influenced by void ratio, with higher void ratios leading to decreased air entry values and residual suctions, underscoring the critical role of void ratio in hydraulic behavior. Additionally, the critical state line (CSL) in the bi-logarithmic space of void ratio and mean effective stress shifts towards higher void ratios with increasing matric suction, significantly affecting dilatancy and critical states. Furthermore, the study demonstrated that the mobilized friction angle and modulus properties depend on confining pressure and matric suction. A novel modified dilatancy equation was proposed, which enhances the predictability of CREFMs' responses under variable loading, particularly at high stress ratios defined by the deviatoric stress over the mean effective stress. This research advances the understanding of CREFMs' performance, especially under fluctuating environmental conditions that alter suction levels.http://www.sciencedirect.com/science/article/pii/S1674775525001507Coarse-grained railway embankment fill materials (CREFMs)Soil-water retention curve (SWRC)Constant-suction triaxial compression testCritical stateDilatancy equationUnsaturated soil
spellingShingle Yuanjie Xiao
Wenqi Li
Liuxin Chen
Xiaoming Wang
Yunbo Li
Pan Tan
Jiapei Du
Characterization of unsaturated coarse-grained railway embankment fill: Water retention and dilatancy
Journal of Rock Mechanics and Geotechnical Engineering
Coarse-grained railway embankment fill materials (CREFMs)
Soil-water retention curve (SWRC)
Constant-suction triaxial compression test
Critical state
Dilatancy equation
Unsaturated soil
title Characterization of unsaturated coarse-grained railway embankment fill: Water retention and dilatancy
title_full Characterization of unsaturated coarse-grained railway embankment fill: Water retention and dilatancy
title_fullStr Characterization of unsaturated coarse-grained railway embankment fill: Water retention and dilatancy
title_full_unstemmed Characterization of unsaturated coarse-grained railway embankment fill: Water retention and dilatancy
title_short Characterization of unsaturated coarse-grained railway embankment fill: Water retention and dilatancy
title_sort characterization of unsaturated coarse grained railway embankment fill water retention and dilatancy
topic Coarse-grained railway embankment fill materials (CREFMs)
Soil-water retention curve (SWRC)
Constant-suction triaxial compression test
Critical state
Dilatancy equation
Unsaturated soil
url http://www.sciencedirect.com/science/article/pii/S1674775525001507
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AT yunboli characterizationofunsaturatedcoarsegrainedrailwayembankmentfillwaterretentionanddilatancy
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