Shear response and spatial evolution of roughness degradation in rock fracture surfaces with heterogeneously distributed multi-angle asperities

Exploring the shear behavior and local roughness degradation of rock fractures with laterally composite dentate profiles

The shear mechanical properties of natural rock fracture play a vital role in resolving complex geotechnical engineering issues. Existing two-dimensional (2D) fracture models fail to capture spatial asperity distribution, while natural three-dimensional (3D) fractures are too random for systematic analysis. To address this, five composite fracture surface models, derived from single-angle dentate profiles, were proposed to represent the spatial characteristics of roughness. Using 3D printed molds, rock-like mortar specimens were fabricated for direct shear testing. Shear behaviors and progressive roughness degradation were quantitatively examined via 3D scanning and the indicator θ*max/(C + 1). Results demonstrate that spatial roughness gradients govern the progressive failure of asperities and the transition from sliding to shearing. Quantitatively, the peak shear strength increases significantly from 1.82 MPa to 14.57 MPa under normal stresses ranging from 2 MPa to 8 MPa. Moreover, the overall roughness reduction exhibits a strong linear correlation with the shear strength, yielding high determination coefficients from 0.805 to 0.942. For practical engineering applications, it is highly recommended to evaluate fracture shear capacity based on the collaborative load transfer of spatially distributed asperities rather than isolated local peaks. These findings provide a vital experimental basis to optimize shear strength models for naturally rough rock fractures.

Fracture behavior and constitutive modeling of rock-concrete contact surfaces with different roughness under freeze–thaw cycles

A JRC3D shear strength model considering failure surface spatial anisotropy of soft rock

Influence of discontinuous gradation and surface morphology on the shear behavior of soil rock mixtures-bedrock interface

Hysteresis Characteristics of Rocks Influenced by Rough Interfaces: A Discrete Element Method Study

Interfaces at multiple scales within rocks critically control the mechanical properties of rock masses. However, the mechanisms by which interface roughness characteristics affect non-plastic deformation remain incompletely understood. In this study, particle-flow simulations were used to conduct loading–unloading tests on rough interfaces. The results show that contact surfaces inclined relative to the overall interface provide additional resistance during unloading and recovery, thereby increasing both the magnitude and likelihood of interfacial hysteresis. This mechanism explains why hysteresis can occur under loading normal to the interface. Differences between the static and dynamic friction coefficients, together with dynamic changes in the normal vectors of the contact surfaces, further intensify the hysteretic response. When deformation of the surrounding material is considered, the “lateral compression–expansion effect” caused by asperity extrusion and interlocking under compression, as well as the slip-induced “dilatancy effect,” also contributes substantially to rough-interface hysteresis. In addition, initial stress on crack surfaces can enhance the degree of hysteresis. The grain-based rock model incorporating interface roughness and in situ stress effectively reproduces the non-plastic hysteretic behavior of rocks.

Multiscale Correlation of Fracture Surface Morphology and Low‐Temperature Mechanical Performance in Asphalt Mixtures

To elucidate low‐temperature cracking mechanisms in asphalt mixtures, this study integrated direct tensile fracture testing with 2D image analysis and 3D laser scanning, linking macroscopic mechanical behavior to microscopic morphology. Results indicate that crack resistance is governed by structural synergy between a coarse aggregate skeleton and ductile modified asphalt. This synergy increases macroscopic fracture process energy during low‐temperature crack propagation. Notably, quantitative analysis of mix designs reveals an optimal filler–binder ratio of 1.2 (F/B = 1.2) for maximizing fracture resistance. Based on surface energy theory, dual‐dimensional analysis reveals the underlying mechanism: The synergistic effect increases spatial surface tortuosity and reduces brittle interfacial failure. Consequently, cracks propagate along intricate paths requiring greater external mechanical work. Furthermore, a comprehensive morphological index was established using principal component analysis. Serving as a thermodynamic indicator of fracture paths, this index provides a quantitative framework for evaluating macroscopic low‐temperature stability beyond mere statistical correlation.