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Investigation of the mechanical behavior of salinized agricultural soils using unsaturated triaxial tests and a constitutive framework
Abstract The salinization of agricultural soil is a common issue of concern. However, the coupling relationship between soil chemical properties and mechanical behavior has been largely ignored. A constant water content triaxial test was conducted by controlling suction on unsaturated agricultural soils collected from paddy fields. The soil samples were diluted with different salt solutions (a distilled water, a sodium chloride (NaCl) solution and a calcium chloride (CaCl2) solution) to investigate the influence of salinity on the mechanical behavior of soils. The pore water pressure of silt loam was significantly influenced by the pore water salinity, while the pore water pressure of silty clay was significantly influenced by the net normal stress. The results showed that the salt type and concentration significantly affected the cohesion value of silt loam. An empirical constitutive model that incorporated osmotic suction was presented in this paper to explain and quantify the effect of pore water salinity on the shear strength of silt loam. Osmotic suction was considered an independent stress variable in the constitutive model, unlike the salt type and concentration. The Barcelona unsaturated constitutive model explained how the pore water salinity affected the mechanical behavior of agricultural silt loam. With an increase in the osmotic suction in silt loam, the yield surface expanded to both sides of the original ellipses, resulting in an increase in cohesion. The constitutive framework considering osmotic suction provides an improved prediction of the mechanical behavior of agricultural soil under natural conditions subjected to salinization/desalinization. This framework can be implemented in a stabilization plan when the soil and salt are involved in agricultural activities.
Highlights A modified unsaturated triaxial test to obtain detailed mechanical behavior of agricultural soils Investigated the influence of soil pore water salinity on the mechanical behavior of agricultural soil. Soil pore water salinity had a higher influence on silt loam than silt clay. The osmotic suction should be considered as an independent stress variable in the constitutive framework.
Investigation of the mechanical behavior of salinized agricultural soils using unsaturated triaxial tests and a constitutive framework
Abstract The salinization of agricultural soil is a common issue of concern. However, the coupling relationship between soil chemical properties and mechanical behavior has been largely ignored. A constant water content triaxial test was conducted by controlling suction on unsaturated agricultural soils collected from paddy fields. The soil samples were diluted with different salt solutions (a distilled water, a sodium chloride (NaCl) solution and a calcium chloride (CaCl2) solution) to investigate the influence of salinity on the mechanical behavior of soils. The pore water pressure of silt loam was significantly influenced by the pore water salinity, while the pore water pressure of silty clay was significantly influenced by the net normal stress. The results showed that the salt type and concentration significantly affected the cohesion value of silt loam. An empirical constitutive model that incorporated osmotic suction was presented in this paper to explain and quantify the effect of pore water salinity on the shear strength of silt loam. Osmotic suction was considered an independent stress variable in the constitutive model, unlike the salt type and concentration. The Barcelona unsaturated constitutive model explained how the pore water salinity affected the mechanical behavior of agricultural silt loam. With an increase in the osmotic suction in silt loam, the yield surface expanded to both sides of the original ellipses, resulting in an increase in cohesion. The constitutive framework considering osmotic suction provides an improved prediction of the mechanical behavior of agricultural soil under natural conditions subjected to salinization/desalinization. This framework can be implemented in a stabilization plan when the soil and salt are involved in agricultural activities.
Highlights A modified unsaturated triaxial test to obtain detailed mechanical behavior of agricultural soils Investigated the influence of soil pore water salinity on the mechanical behavior of agricultural soil. Soil pore water salinity had a higher influence on silt loam than silt clay. The osmotic suction should be considered as an independent stress variable in the constitutive framework.
Investigation of the mechanical behavior of salinized agricultural soils using unsaturated triaxial tests and a constitutive framework
Hongde, Wang (author) / Dongli, She (author) / Xiaoqin, Sun (author) / Donghao, Ma (author)
Engineering Geology ; 299
2022-02-10
Article (Journal)
Electronic Resource
English
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