Cryo-mechanics of unsaturated frozen soils during freeze-thaw cycle.
Abstract
While previous theoretical and experimental studies have established that yield surfaces of frozen soils may change their size and shape due to temperature changes, the mechanical behavior of soils subjected to freeze-thaw cycle remains poorly understood. The difficulty on modeling and predicting the mechanical behavior of frozen soils is attributed to the complex thermo-hydro-mechanical coupling effects during the freezing and thawing conditions. For instance, the evaporation and crystallization of the liquid phases, the evolving cryo-suction processes, the interfacial effects among solid matrix, ice, unfrozen liquid water and air, and the difference in the density between water and ice are all important factors that affect the mechanical responses of the frozen ground, cause frost heave, fractures and cracks on pavement and buildings, and limit vehicle mobility in cold regions. The objective of this DURIP research is to advance the fundamental understanding of the path dependent behaviors of soils during freeze-thaw cycles. An experimental triaxial cell system equipped with a climate control system and an unsaturated soil triaxial module will be used to vary temperature, axial and radial stresses, as well as air and water pressures of soils monotonically and cyclically. The stress-strain history, water retention behavior and relative permeability at various stages of loading cycles will be recorded. By examining the cryo-deformation of specimens subjected to various combinations of drainage conditions, degree of saturations and loading paths, this research will bring the much needed new insights on how crystallization and thawing of ice crystal inside the pore space affects the macroscopic responses of frozen soils. A large strain thermo-poro-plasticity constitutive model will be used in complement with this experimental research to develop validated theory that explains the thermo-hydro-mechanical responses of frozen soil during freeze-thaw cycles.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 14, 2019
- Source ID
- W911NF1510442
Entities
People
- WaiChing Sun
Organizations
- Army Contracting Command
- Columbia University
- United States Army