Granular Mechanics and Soil Behavior

Granular materials such as sand, silt and gravel occupy a pivotal role in natural and engineered systems, exhibiting behaviour that bridges solid and fluid mechanics. At the grain scale, contact forces, frictional interactions and fluid–solid coupling give rise to emergent phenomena including force chains, fabric anisotropy and pore-pressure evolution. Macroscopically, these interactions govern shear strength, compressibility, permeability and flow, which are critical for slope stability, foundation performance, earth retaining structures and the assessment of geohazards such as liquefaction. Recent progress in imaging, numerical simulation and biogeotechnical methods has deepened our understanding of micro-to-macro transitions, enabling more reliable predictions of soil response under complex loading, environmental and chemical conditions. This interdisciplinary field continues to evolve through the integration of advanced constitutive models, data-driven techniques and sustainable soil-improvement strategies, thereby enhancing resilience in infrastructure and environmental applications.

Research from Nature Portfolio

Recent work has overturned the classic view that earthquake-induced liquefaction requires undrained conditions at high energy density. New findings demonstrate that drained liquefaction can occur at low seismic-energy input, as fluid migration generates pore-pressure gradients that propagate a compaction front and precipitate rapid loss of soil strength even at considerable distances from an epicentre. This insight urges a re-evaluation of hazard-assessment models and mitigation strategies in seismic regions. In parallel, enzyme-induced carbonate precipitation has been harnessed to produce high-strength soil specimens at minimal carbonate content. By combining free urease enzyme with organic additives, researchers achieved targeted calcium-carbonate bond formation at interparticle contacts, significantly enhancing compressive strength while minimising substrate and by-product generation. This bio-cementation approach promises a greener alternative for ground stabilisation with lower material and energy requirements.

Granular Mechanics and Soil Behavior publication trend

The graph below shows the total number of articles in granular mechanics and soil behavior across all publications each year (not limited to Nature Index journals).

Technical terms

Granular material: An assembly of discrete solid particles whose collective behaviour arises from individual grain interactions.

Liquefaction: Sudden loss of soil strength and stiffness due to increased pore pressure under dynamic or static loading.

Drained condition: A state in which pore fluids can migrate freely, allowing pressure dissipation during deformation.

Undrained condition: A state in which pore fluids cannot escape, causing pressure build-up within the soil mass.

Microbial-induced carbonate precipitation (MICP): A bio-geochemical method using urease or bacteria to precipitate calcium carbonate within soil pores for reinforcement.

Discrete Element Method (DEM): A numerical technique that simulates the motion and interaction of individual particles to predict macroscopic behaviour.

Angle of repose: The steepest angle at which a pile of granular material remains stable without sliding.

Pore pressure: Pressure of the interstitial fluid within the voids of a soil or granular assembly, influencing effective stress and strength.

References

1. Drainage explains soil liquefaction beyond the earthquake near-field. Nature Communications (2023).
2. Enzyme Induced Biocementated Sand with High Strength at Low Carbonate Content. Scientific Reports (2019).
3. State-of-the-art review on the use of AI-enhanced computational mechanics in geotechnical engineering. Artificial Intelligence Review (2024).
4. A review on the angle of repose of granular materials. Powder Technology (2018).
5. Effect of Young’s Modulus and Surface Roughness on the Inter-Particle Friction of Granular Materials. Materials (2018).