Mechanical Behavior of Jointed Rock Masses

Jointed rock masses, characterised by networks of fractures, fissures and faults, display mechanical behaviour governed by both the intact rock material and the geometry, orientation and infill of discontinuities. Under loading, these discontinuities localise deformation, govern crack initiation and propagation, and control energy dissipation. Laboratory experiments and numerical simulations reveal that joint density, spacing and dip angle markedly influence stiffness, peak strength and post-peak softening. Energy partitioning studies show frictional losses dominate during shear, while microcrack accumulation precedes macroscopic failure. Anisotropy introduced by aligned joints gives rise to directional dependence of uniaxial compressive strength and shear resistance, with failure modes ranging from tensile wing cracks to mixed tension–shear and pure shear fractures. In situ applications – from tunnels and slopes to hydro-fracturing and geothermal wells – require reliable prediction of jointed mass response to static and dynamic loads. Advances in micro-mechanical modelling, acoustic emission monitoring and high-resolution imaging have deepened understanding of the interplay between discontinuity architecture and rock matrix, enabling improved design and risk assessment in civil, mining and energy-related geotechnical engineering.

Research from Nature Portfolio

Recent studies have investigated how grain size distribution and pre-existing crack length affect both crack evolution and acoustic emission signatures under uniaxial compression in rock-like materials. Variations in grain size composition alter crack initiation sites and govern whether failure is progressive or brittle. Multiple crack types – including tensile wing, transverse shear and anti-tensile wing cracks – develop depending on fissure length and orientation. Acoustic emission energy exhibits distinct patterns: specimens with short cracks show rapid emission peaks accompanying sudden brittle failure, whereas those with longer fissures display repeated rises and falls in emission as cracks propagate progressively. These findings offer concrete guidance for acoustic monitoring and early warning in jointed rock masses.

Mechanical Behavior of Jointed Rock Masses publication trend

The graph below shows the total number of articles in mechanical behavior of jointed rock masses across all publications each year (not limited to Nature Index journals).

Technical terms

Joint: A planar discontinuity in rock along which there has been no visible shear displacement.

Discontinuity: Any break or plane of weakness in rock, including joints, fissures and faults.

Shear strength: The maximum shear stress a rock discontinuity or mass can sustain before failure.

Acoustic emission: Transient elastic waves generated by sudden microfracturing events within a material under stress.

Particle Flow Code (PFC): A discrete element modeling method that represents rock as an assembly of bonded particles to simulate fracturing and deformation.

References

1. Shear mechanical properties and energy evolution of rock-like samples containing multiple combinations of non-persistent joints. Journal of Rock Mechanics and Geotechnical Engineering (2023).
2. The Effect of Joint Dip Angle on the Mechanical Behavior of Infilled Jointed Rock Masses under Uniaxial and Biaxial Compressions. Processes (2018).
3. Mechanical and failure characteristics of rock-like material with multiple crossed joint sets under uniaxial compression. Advances in Mechanical Engineering (2017).
4. Impact of loading rate on the mechanical behavior of jointed rock. Geomechanics and Geophysics for Geo-Energy and Geo-Resources (2023).
5. Experimental study on crack characteristics and acoustic emission characteristics in rock-like material with pre-existing cracks. Scientific Reports (2021).