Thermal cycling effects on the properties of coarse-grained soils: numerical and experimental investigation
Abstract
Overview: Coarse-grained soils and other granular materials are extremely abundant globally and have been classified as the second most handled material after water. Due to natural and anthropogenic perturbations involving the transfer of heat, these materials often undergo cyclic temperature variations. Thermal cycling causes a modification of the structure of coarse-grained soils and other granular materials due to particle rearrangements. Modifications in the structure of such materials at the microscopic scale can markedly influence their multiphysical properties and behavior at the macroscopic scale (e.g., thermo-hydro-mechanical), controlling the related capability to sustain mechanical loads, allow fluids permeation and transfer heat. Thermal cycling effects thus have crucial scientific and engineering implications. For example, these effects can impact the stability of coarse-grained soil masses and slopes, the resilience of the supported structures, and the effectiveness of energy harvesting or storage using these materials. In recent years, studies have been performed to investigate the thermal cycling effects on the behavior of coarse-grained soils and other granular materials, highlighting irreversible contractive volumetric deformations. However, no dedicated studies to unravel the thermal cycling effects on the properties of coarse-grained soils and other granular materials have been performed. Project goals: The intellectual merit of this short-term innovative research (STIR) is to provide, for the first time, fundamental knowledge about the thermal cycling effects on the properties of coarsegrained soils using an integrated numerical and experimental investigation across scales. To tackle this challenge, the present study will utilize numerical discrete element simulations and experimental oedometric laboratory tests with temperature control and advanced measuring capabilities. At the microscopic scale of the particles that constitute coarse-grained soils, the numerical simulations will investigate the variations in the structure of such materials caused by heating-cooling cycles. At the macroscopic scale, the experimental tests and numerical simulations will address the associated variations of selected material properties (i.e., stiffness, hydraulic conductivity and thermal conductivity). This research is both innovative and risky as it investigates an unexplored subject, employs advanced investigation methods and has the potential to result scientific and engineering breakthroughs. In fact, not only will this research improve the knowledge and understanding of the unexplored thermal cycling effects on the properties of coarse-grained soils via cutting-edge numerical and experimental methods, but it will also assess the merit of using thermal cycles as a breakthrough means to engineer the properties and behavior of coarse-grained soils and other materials. Army relevance and impact: The understanding of the thermal cycling effects on the properties of coarse-grained soils can provide novel information to assess their response to temperature variations and to modify, tailor and control their response via temperature variations (e.g., causing irreversible deformations and changes in the material properties). This knowledge can serve to create constitutive frameworks and models for scientific and engineering purposes, and unravel revolutionary techniques to engineer soils and other materials via thermal treatments. By triggering a change in the structure of soils through thermal cycles and modifying their properties and behavior, such treatments may fundamentally contribute to the mission of the U.S Army via the prevention of natural hazards (e.g., slope stabilization and reduction of liquefaction potential), the protection of structures and infrastructures (e.g., stiffening of road beds), and the development of enhanced geoenergy harvesting and material storage solutions
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jun 25, 2021
- Source ID
- W911NF2110059
Entities
People
- Alessandro Rotta Loria
Organizations
- Army Contracting Command
- Northwestern University
- United States Army