Main factor inducing mining dynamic disasters: Fault activation in mining disturbance

In underground geological structures, faults activation is frequently encountered during the process of coal mining. These geological structures have seriously damaged the continuity and integrity of the rock strata, in many parts of the world. The activation of faults has consistently been a critical factor impacting the safety of coal mining operations. Consequently, there is an urgent need to investigate the instability and failure of surrounding rock caused by fault activation.

To that end, a team of researchers from China conducted a comprehensive study on the impact of disturbance stress and roof abscission layer monitoring within zones affected by fault activation. The aim was to establish a theoretical foundation for effective roadway support.

“We utilized the discrete element 3DEC numerical analysis method to construct a model that simulates the unstable fracture of the surrounding rock resulting from fault activation,” explained Jie Chen, lead author of the study. “Specifically, we focused on the excavation of the upper and lower side walls of the faults, examining the characteristics of unstable fracture and stress variations in the surrounding rock induced by fault activation.”

The team found that as the coal working face progresses, the mining stress progressively intensifies. A zigzag wave pattern was observed on the relationship curve between coal mining and roof displacement in the vicinity of the fault (Figs. 1 and 2).

“This pattern indicates that the surrounding rock in the fault activation affected zone experiences a combination of static and dynamic loads,” added Chen.

“Simulation results further demonstrate that the stress and displacement of the surrounding rock near the fault increase as the coal mining face advances,” said co-corresponding author Yuanyuan Pu. “The recommended safe distance when approaching the fault is 30 meters. Conversely, the numerical tests indicate a slightly shorter safe distance of 26 meters when approaching the fault.” (Fig. 3)

The team hopes that their latest findings, published in the KeAi journal Rock Mechanics Bulletin, can get more attention in the field of mining safety to improve the safe and efficient mining of coal mines.

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Contact author details: Jie Chen, School of Resources and Safety Engineering, Chongqing University, Chongqing 400044, China, jiechen023@cqu.edu.cn; Yuanyuan Pu, School of Resources and Safety Engineering, Chongqing University, Chongqing 400044, China, yuanyuanpu@cqu.edu.cn.

See the article: Chen J, Shi K, Pu Y, et al. Study on instability fracture and simulation of surrounding rock induced by fault activation under mining influence[J]. Rock Mechanics Bulletin, 2023, 2(2): 100037.