geomaterials

Geomaterials are natural and engineered materials derived from the Earth that exhibit complex mechanical, hydraulic, thermal, and chemical behavior. They include soils, rocks, sediments, ice, and cemented earth materials such as concrete-like composites. In engineering and geoscience, geomaterials are studied for their response under loading, moisture variation, temperature changes, and chemical interaction.

Common properties include grain size distribution, mineralogy, porosity, permeability, density, shear strength, stiffness, and compressibility. Their behavior is often governed by microstructure, pore network, mineralogy (especially clay minerals), and moisture conditions. Geomaterials show anisotropy, hysteresis, and time-dependent effects such as consolidation and creep.

Classification: by origin (igneous, sedimentary, metamorphic), by texture (granular soils, clay minerals), by grain size (coarse-grained vs fine-grained), by water content (dry, saturated, partially saturated), and by phase (soils, rocks, ice). Engineered geomaterials include cemented soils, geosynthetics, and rock-like composites used in construction.

Testing and modeling: Characterization relies on laboratory tests such as oedometer, direct shear, triaxial, and permeability tests, as well as index tests for grain size and Atterberg limits. Numerical modeling uses constitutive frameworks from soil mechanics, including critical state theory and plasticity models, to capture strength, dilatancy, and stability under varying humidity and drainage conditions.

Applications: geomaterials underpin civil infrastructure design, mining, groundwater and contaminant containment, energy storage and geothermal systems, and studies of planetary materials. They pose challenges due to heterogeneity, nonlinear behavior, time-dependent properties, and scale effects, requiring integrated field and laboratory approaches.