Engineering and Technological Sciences
Abstract
The bound water in saturated clay, due to its unique double-layer structure, plays a critical role in controlling the macroscopic thermo-mechanical behavior of clay. This paper focuses on the mechanism of bound water variation with temperature in saturated clay. By comparing research results from different scholars, it is found that slight differences in bound water density lead to significant discrepancies in the calculated bound water content, thereby affecting the analysis of thermal response patterns.
Furthermore, this study discusses the applicability and limitations of the isothermal adsorption method, pointing out that this method essentially simulates unsaturated conditions, and the bound water content measured is often lower than the actual level under saturated conditions. Additionally, it is difficult to distinguish bound water from free water at high humidity levels.
Regarding the trend of bound water content variation with temperature, this paper, based on an improved specific gravity test, measures changes in specific gravity as the temperature increases from 20 ℃ to 50 ℃. Combined with theoretical calculations, the evolution pattern of bound water content is obtained, revealing that bound water exhibits a typical "slow-fast-slow" decay characteristic as temperature rises.
The study indicates that this thermal response of bound water fundamentally stems from changes in the double-layer thickness and the reconstruction of the particle-water interface energy structure. In engineering practice, accurately characterizing the temperature dependence of bound water is crucial for predicting volume changes and strength variations in clay, which can significantly enhance the safety and reliability of underground energy structures and geothermal systems under thermo-mechanical coupled environments.
Full Text
Study on the Variation of Bound Water Content in Saturated Clay with Temperature
Study on the Temperature-Dependent Variation of Bound Water Content in Saturated Clays
Zilin Yuan¹, Zhongtao Wang¹, Hao Wang¹
¹ State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024
Abstract
The bound water in saturated clay, due to its unique electrical double-layer structure, plays a critical role in controlling the macroscopic thermo-mechanical behavior of clay. This paper focuses on the mechanism of temperature-dependent variations of bound water in saturated clay. By comparing research results from different scholars, it is found that minor differences in bound water density can lead to significant discrepancies in the calculated bound water content, thereby affecting the analysis of thermal response patterns.
Furthermore, this study discusses the applicability and limitations of the isothermal adsorption method, pointing out that this method essentially simulates unsaturated conditions, where the measured bound water content is often lower than the actual level under saturated conditions, and it is difficult to distinguish between bound water and free water at high humidity levels.
Regarding the trend of bound water content variation with temperature, this study, based on an improved specific gravity test, measures the changes in specific gravity as the temperature increases from 20 °C to 50 °C. Combined with theoretical calculations, the evolution pattern of bound water content is obtained, revealing that bound water exhibits a typical "slow-fast-slow" decay characteristic as temperature increases.
The research indicates that this thermal response of bound water fundamentally stems from changes in the electrical double-layer thickness and the reconstruction of the particle-water interface energy structure. In engineering practice, accurately characterizing the temperature dependence of bound water is crucial for predicting volume changes and strength variations in clay, which can significantly enhance the safety and reliability of underground energy structures and geothermal systems under thermo-mechanical coupled environments.
Keywords: saturated clay; bound water content; bound water density; temperature; thermo-mechanical coupling
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This version posted 2025-09-02.