Large-scale asymmetric pulverisation of fault zone: Insights from rock axial strain in static and dynamic loading conditions

The open question of asymmetric large-scale pulverisation of fault zone was experimentally investigated in this paper. It is found that the transition of rock fracture from local splitting to pervasive pulverisation is controlled by strain both in quasi-static and dynamic conditions. This can explain the asymmetric damage in the fault zone as the strain threshold to pulverisation for stiffer rock is lower. In terms of the cyclic dynamic loadings, four types of fracture patterns (lateral tension, axial split, spatial fragmentation, and pervasive pulverisation) were developed with the increase of strain. Subject to the long-term quasi-static and dynamic load, the cumulative damage to the fault zone broadens the scale of pulverisation. In light of the linear correlation of energy absorption to strain, the damage relationships between strain and loading cycles were established and found to offer a good prediction of experimental data.

Automated summary

The experimental study reveals that the transition of rock fracture from local splitting to pervasive pulverisation is strain-controlled, leading to asymmetric damage in fault zones. As strain increases, different fracture patterns develop, ultimately broadening the scale of pulverisation due to cumulative damage. The linear correlation between energy absorption and strain allows for a good prediction of experimental data on the relationship between strain and loading cycles.