Effects of microstructure on desiccation cracking of a compacted soil

Qing Cheng, Chao Sheng Tang, Hao Zeng, Cheng Zhu, Ni An, Bin Shi

Research output: Contribution to journalArticle

Abstract

Desiccation cracking has a significant influence on the hydro-mechanical behaviour of soils. Most previous studies focus on the desiccation cracking of slurry soil samples, whereas little attention has been paid to compacted soils. This study aims to investigate the effects of microstructure on the desiccation cracking of a compacted lean clay. Five soil samples are mixed with different water contents including 12.5%, 14.5%, 16.5% (optimum water content), 18.5%, and 20.5%, compacted to generate different initial soil microstructures. After compaction, the soil samples are subjected to saturation and then the same drying process. The pore size distribution of each soil sample is characterized by performing mercury intrusion porosimetry (MIP) test. The change in water content and the evolution of surface crack pattern during the drying process are continuously monitored. Experimental results show that the addition of water content during soil compaction significantly influences the microstructure and desiccation cracking behaviour of soils. With increasing compaction water content from the dry side to the wet side of the optimum water content, soil microstructure transits from an aggregate structure to a dispersed structure, resulting in the change of pore size distribution from bimodal to unimodal. For soils with aggregate structures, the desiccation cracks initiate simultaneously and distribute uniformly throughout the soil body. With decreasing water content, crack geometrical parameters such as surface crack ratio and crack density increase almost linearly. Comparatively, for soils with dispersed structures, more localized growth of primary and secondary cracks are observed and the crack geometrical parameters show a two-stage linear growth during drying. This study provides microstructural interpretations to important aspects of desiccation cracking in compacted clayey soils and may guide the design of clay materials for geotechnical engineering applications.

Original languageEnglish (US)
Article number105418
JournalEngineering Geology
Volume265
DOIs
StatePublished - Feb 2020

Fingerprint

desiccation
microstructure
Soils
Microstructure
Water content
crack
water content
soil
Cracks
Drying
Compaction
cracking (fracture)
effect
compaction
Pore size
Clay
clay
Geotechnical engineering
geotechnical engineering
slurry

All Science Journal Classification (ASJC) codes

  • Geology
  • Geotechnical Engineering and Engineering Geology

Cite this

Cheng, Qing ; Tang, Chao Sheng ; Zeng, Hao ; Zhu, Cheng ; An, Ni ; Shi, Bin. / Effects of microstructure on desiccation cracking of a compacted soil. In: Engineering Geology. 2020 ; Vol. 265.
@article{5e8f0ea21d2e4a8ca9728a826352da28,
title = "Effects of microstructure on desiccation cracking of a compacted soil",
abstract = "Desiccation cracking has a significant influence on the hydro-mechanical behaviour of soils. Most previous studies focus on the desiccation cracking of slurry soil samples, whereas little attention has been paid to compacted soils. This study aims to investigate the effects of microstructure on the desiccation cracking of a compacted lean clay. Five soil samples are mixed with different water contents including 12.5{\%}, 14.5{\%}, 16.5{\%} (optimum water content), 18.5{\%}, and 20.5{\%}, compacted to generate different initial soil microstructures. After compaction, the soil samples are subjected to saturation and then the same drying process. The pore size distribution of each soil sample is characterized by performing mercury intrusion porosimetry (MIP) test. The change in water content and the evolution of surface crack pattern during the drying process are continuously monitored. Experimental results show that the addition of water content during soil compaction significantly influences the microstructure and desiccation cracking behaviour of soils. With increasing compaction water content from the dry side to the wet side of the optimum water content, soil microstructure transits from an aggregate structure to a dispersed structure, resulting in the change of pore size distribution from bimodal to unimodal. For soils with aggregate structures, the desiccation cracks initiate simultaneously and distribute uniformly throughout the soil body. With decreasing water content, crack geometrical parameters such as surface crack ratio and crack density increase almost linearly. Comparatively, for soils with dispersed structures, more localized growth of primary and secondary cracks are observed and the crack geometrical parameters show a two-stage linear growth during drying. This study provides microstructural interpretations to important aspects of desiccation cracking in compacted clayey soils and may guide the design of clay materials for geotechnical engineering applications.",
author = "Qing Cheng and Tang, {Chao Sheng} and Hao Zeng and Cheng Zhu and Ni An and Bin Shi",
year = "2020",
month = "2",
doi = "https://doi.org/10.1016/j.enggeo.2019.105418",
language = "English (US)",
volume = "265",
journal = "Engineering Geology",
issn = "0013-7952",
publisher = "Elsevier",

}

Effects of microstructure on desiccation cracking of a compacted soil. / Cheng, Qing; Tang, Chao Sheng; Zeng, Hao; Zhu, Cheng; An, Ni; Shi, Bin.

In: Engineering Geology, Vol. 265, 105418, 02.2020.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Effects of microstructure on desiccation cracking of a compacted soil

AU - Cheng, Qing

AU - Tang, Chao Sheng

AU - Zeng, Hao

AU - Zhu, Cheng

AU - An, Ni

AU - Shi, Bin

PY - 2020/2

Y1 - 2020/2

N2 - Desiccation cracking has a significant influence on the hydro-mechanical behaviour of soils. Most previous studies focus on the desiccation cracking of slurry soil samples, whereas little attention has been paid to compacted soils. This study aims to investigate the effects of microstructure on the desiccation cracking of a compacted lean clay. Five soil samples are mixed with different water contents including 12.5%, 14.5%, 16.5% (optimum water content), 18.5%, and 20.5%, compacted to generate different initial soil microstructures. After compaction, the soil samples are subjected to saturation and then the same drying process. The pore size distribution of each soil sample is characterized by performing mercury intrusion porosimetry (MIP) test. The change in water content and the evolution of surface crack pattern during the drying process are continuously monitored. Experimental results show that the addition of water content during soil compaction significantly influences the microstructure and desiccation cracking behaviour of soils. With increasing compaction water content from the dry side to the wet side of the optimum water content, soil microstructure transits from an aggregate structure to a dispersed structure, resulting in the change of pore size distribution from bimodal to unimodal. For soils with aggregate structures, the desiccation cracks initiate simultaneously and distribute uniformly throughout the soil body. With decreasing water content, crack geometrical parameters such as surface crack ratio and crack density increase almost linearly. Comparatively, for soils with dispersed structures, more localized growth of primary and secondary cracks are observed and the crack geometrical parameters show a two-stage linear growth during drying. This study provides microstructural interpretations to important aspects of desiccation cracking in compacted clayey soils and may guide the design of clay materials for geotechnical engineering applications.

AB - Desiccation cracking has a significant influence on the hydro-mechanical behaviour of soils. Most previous studies focus on the desiccation cracking of slurry soil samples, whereas little attention has been paid to compacted soils. This study aims to investigate the effects of microstructure on the desiccation cracking of a compacted lean clay. Five soil samples are mixed with different water contents including 12.5%, 14.5%, 16.5% (optimum water content), 18.5%, and 20.5%, compacted to generate different initial soil microstructures. After compaction, the soil samples are subjected to saturation and then the same drying process. The pore size distribution of each soil sample is characterized by performing mercury intrusion porosimetry (MIP) test. The change in water content and the evolution of surface crack pattern during the drying process are continuously monitored. Experimental results show that the addition of water content during soil compaction significantly influences the microstructure and desiccation cracking behaviour of soils. With increasing compaction water content from the dry side to the wet side of the optimum water content, soil microstructure transits from an aggregate structure to a dispersed structure, resulting in the change of pore size distribution from bimodal to unimodal. For soils with aggregate structures, the desiccation cracks initiate simultaneously and distribute uniformly throughout the soil body. With decreasing water content, crack geometrical parameters such as surface crack ratio and crack density increase almost linearly. Comparatively, for soils with dispersed structures, more localized growth of primary and secondary cracks are observed and the crack geometrical parameters show a two-stage linear growth during drying. This study provides microstructural interpretations to important aspects of desiccation cracking in compacted clayey soils and may guide the design of clay materials for geotechnical engineering applications.

UR - http://www.scopus.com/inward/record.url?scp=85075264376&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85075264376&partnerID=8YFLogxK

U2 - https://doi.org/10.1016/j.enggeo.2019.105418

DO - https://doi.org/10.1016/j.enggeo.2019.105418

M3 - Article

VL - 265

JO - Engineering Geology

JF - Engineering Geology

SN - 0013-7952

M1 - 105418

ER -