4 / 2025-07-04 10:47:44

Hydrothermal Characteristics Evolution Mechanisms and Coupling Modeling in Seasonally Frozen Turfy Soil under Freezing-Thawing Process

Turfy soil,Seasonally frozen soil,Hydro-thermal characteristics,Coupling model,Organic matter content

The high organic matter content and elevated moisture characteristics of turfy soil lead to significant hydrothermal evolution during the freezing-thawing process, resulting in intense frost heave and thaw settlement effects. These processes pose severe engineering frost damage risks to pipelines and roadbeds in turfy soil distribution regions. Therefore, this study focuses on the high organic content and moisture characteristics of turfy soil to clarify the hydrothermal evolution mechanisms and analyze internal hydro-thermal distribution patterns, which are crucial for frost damage prevention. The research employs nuclear magnetic resonance (NMR) to measure moisture variation in the freezing-thawing turfy soil, combined with soil-water characteristic curves (SWCC), mercury intrusion porosimetry (MIP), and computed tomography (CT) tests to reveal the mesoscale mechanisms underlying moisture characteristics evolution. It establishes unfrozen water content and permeability coefficient models considering high organic content characteristics while clarifying the phase composition and hydrological properties of freezing-thawing turfy soil. Through component separation and synchronous thermal analysis, the investigation explores how organic components affect the thermophysical properties of freezing-thawing turfy soil, highlighting dynamic phase composition changes and thermophysical differences among components. The study characterizes thermal conductivity and specific heat capacity of freezing-thawing turfy soil as fundamental parameters for hydrothermal coupling. Integrating hydrothermal characteristics of freezing-thawing turfy soil, this work establishes a hydrothermal coupling model for seasonally frozen turfy soil regions, conducts freezing-thawing model experiments to verify and optimize the coupling model, and provides theoretical support for analyzing hydrothermal process evolution in turfy soil. These findings offer technical solutions for engineering frost damage prevention in turfy soil distribution areas.