Failure process and mechanism of sandstone under
combined equal biaxial static compression and impact
J. Y. Peng
| F. P. Zhang
| Z. G. Qiu
Key Laboratory of Ministry of Education
on Safe Mining of Deep Metal Mines,
Northeastern University, Shenyang
School of Science, Northeastern
University, Shenyang 110819, China
J. Y. Peng, Key Laboratory of Ministry of
Education on Safe Mining of Deep Metal
Mines, Northeastern University,
Shenyang, Liaoning 110819, China.
National Natural Science Foundation of
China, Grant/Award Number: 51674061;
State Key Research Development Program
of China, Grant/Award Numbers:
2017YFC0602902, 2016YFC0801605 and
The process and mechanism of impact fractures in sandstone were investigated
under equal biaxial static compression. The cracking process was captured by a
high‐speed video camera. The results indicate that the main crack propagates
along the circumference and finally forms a crater‐shaped failure zone. The size
of the crater‐shaped failure zone increases as the static stress and impact veloc-
ity increase. In addition, microscopic features of the fracture surface were
observed using a scanning electron microscope. It was found that the
microcracks expand after combination loading, making the rock more suscepti-
ble to damage. Finally, the influence mechanism of static loading on dynamic
failure of the rock was revealed by theoretical analysis and numerical
equal biaxial static loading, fracture mechanism, microscopic feature, sandstone
1 | INTRODUCTION
High geo‐stress is one of the main characteristics of deep geological bodies .
A crater‐shaped failure zone is a common
form of failure during rock excavation, such as cut blasting in tunnelling, mining using the vertical crater retreat method,
and crater blasting. Rock fractures under the combined effects of geo‐stress and dynamic stress in deep engineering
works. Because of the significant effects of geo‐stresses on rock failure zone, it is important to study the dynamic failure
process and mechanism of rock under static loading.
The static stress environment significantly affects the dynamic mechanical properties and failure process of
rocks. The compressive strength of rock under coupling loads first increases and then decreases as the static
whereas the tensile strength of the granite under combined loading decreases with increases
in static stresses, indicating that less explosive might be needed to excavate rock under higher geo‐stresses.
dynamic failures under uniaxial or unequal biaxial static loads, the cracking direction is consistent with the max-
imum principal stress, and the static stress affects the shape of the failure zone.
Studies on the failure process
under combined equal biaxial static compression and dynamic loading are relatively rare, although some
researchers have undertaken relevant work. For example, Zhu et al.
investigated the effect of initial stress on
air blasting using a plane two‐dimensional numerical simulation and found that the fractures in all directions
are restrained under equal biaxial static compression. Zhang et al.
carried out explosion crater tests in the case
of a single free surface under equal biaxial static loading, which showed that the crater volume first decreases and
Received: 5 August 2017 Revised: 10 December 2017 Accepted: 19 December 2017
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