Fracture Mechanics in Geological and Rock-Like Materials

Fracture mechanics in geological and rock-like materials examines how cracks initiate, propagate and coalesce under natural and engineered loading conditions. At the core of this discipline is the interplay between material heterogeneity—such as grain boundaries, pores and pre-existing flaws—and applied stress fields that drive crack growth. Advances in laboratory experiments, numerical modelling and high-resolution imaging have elucidated mechanisms from the microscale, where individual grains rotate or slide, to the macroscale, where networks of fractures govern the large-scale stability of slopes, tunnels and reservoirs. Understanding these processes underpins reliable predictions of seismic events, resource extraction safety and long-term infrastructure resilience. Multiphysics approaches now integrate fluid pressure, thermal effects and chemical alterations, highlighting the global significance of fracture control in geothermal energy, carbon storage and underground construction.

Research from Nature Portfolio

Recent studies employing in situ synchrotron X-ray imaging under triaxial compression have revealed that fracture orientations in rock specimens evolve from shear-dominated modes to opening-mode, or extensile, fracturing as samples approach macroscopic failure. This transition reflects an optimisation of mechanical efficiency and provides a physical basis for empirical friction laws used in crustal failure criteria. In parallel, combined acoustic monitoring and time-resolved X-ray imaging of porous rock has shown that local strain can accumulate aseismically through grain and crack rotation within emergent shear zones. These experiments demonstrate that seismic amplitude does not always correlate with strain localisation, and that the energy dissipated on faults may be substantially lower than bulk estimates. Together, these insights refine our understanding of critical transitions from stable crack growth to dynamic rupture.

Fracture Mechanics in Geological and Rock-Like Materials publication trend

The graph below shows the total number of articles in fracture mechanics in geological and rock-like materials across all publications each year (not limited to Nature Index journals).

Technical terms

Triaxial compression: a laboratory test applying controlled stresses along three perpendicular axes to simulate subsurface conditions.

Extensile fracture: an opening-mode crack where tensile normal stress separates the faces of a crack.

Shear fracture: a crack characterised by relative lateral displacement of its faces under shear stress.

Digital volume correlation (DVC): a technique for measuring three-dimensional strain fields by tracking texture changes in successive volumetric images.

Fracture network: an interconnected system of cracks whose geometry and connectivity govern bulk mechanical behaviour.

Stress intensity factor (SIF): a parameter quantifying the stress state near the tip of a crack, dictating crack growth propensity.

References

1. Deformation evolves from shear to extensile in rocks due to energy optimization. Communications Earth & Environment (2023).
2. Seismic events miss important kinematically governed grain scale mechanisms during shear failure of porous rock. Nature Communications (2022).
3. Experimental Investigation and Numerical Simulation on the Crack Initiation and Propagation of Rock With Pre-Existing Cracks. IEEE Access (2020).
4. Crack Initiation, Propagation, and Failure Characteristics of Jointed Rock or Rock‐Like Specimens: A Review. Advances in Civil Engineering (2019).
5. Catastrophic Failure: How and When? Insights From 4‐D In Situ X‐ray Microtomography. Journal of Geophysical Research: Solid Earth (2020).
6. Influence of Flaw Inclination Angle on Cracking Behavior of Rock‐Like Materials under Uniaxial Compression. Advances in Materials Science and Engineering (2019).