Brittleness Characterization in Geomaterials

Brittleness in geomaterials refers to the propensity of rocks, soils and other subsurface formations to fracture abruptly once stress exceeds a critical threshold, with little prior plastic deformation. Accurate characterisation of this property underpins safer tunnelling, mining, wellbore stability, hydraulic fracturing and geothermal operations. Traditionally, brittleness has been inferred from empirical indices derived from uniaxial and triaxial stress–strain curves, combining elastic moduli, peak strength and post-peak softening rates. More recent approaches integrate energy analysis, measuring the ratio of elastic energy release to dissipated energy during failure, and exploit multiscale imaging—such as X-ray computed tomography and scanning electron microscopy—to reveal microcrack initiation and propagation. Advanced acoustic-emission monitoring and high-speed imaging further elucidate fracture dynamics in real time. Numerical methods, including discrete element and synthetic rock mass models, enable parametric studies of mineralogical contrasts, confining pressures and loading rates. Together, these techniques reveal how factors such as pore pressure, temperature, chemical alteration and stress path influence the transition from ductile response to brittle failure. Improved brittleness characterisation supports optimal design of excavation sequences, hydraulic fracturing schedules and reservoir stimulation, reducing environmental risks and enhancing resource recovery worldwide.

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Brittleness Characterization in Geomaterials publication trend

The graph below shows the total number of articles in brittleness characterization in geomaterials across all publications each year (not limited to Nature Index journals).

Technical terms

Brittleness: Propensity of a geomaterial to fracture abruptly with limited plastic deformation.

Confining pressure: Isostatic pressure applied to a specimen to simulate in-situ stress conditions.

True triaxial stress: Stress state in which three principal stresses are independently imposed (σ1, σ2, σ3).

Stress–strain curve: Plot of applied stress versus resulting strain, revealing elastic, peak and post-peak behaviour.

Acoustic emission: High-frequency elastic waves generated by microcrack growth, used to monitor fracture processes.

References

1. Assessing the Fracturing Process of Rocks Based on Burst–Brittleness Ratio (BBR) Governed by Point Load Testing. Rock Mechanics and Rock Engineering (2023).
2. Cracking property and brittleness evaluation of granite under high-temperature true triaxial compression in geothermal systems. Geomechanics and Geophysics for Geo-Energy and Geo-Resources (2023).
3. Ductile–brittle quantitative evaluation of rock based on post-peak properties under true triaxial stress. Geomechanics and Geophysics for Geo-Energy and Geo-Resources (2023).