Work

Mechanism and risk identification of rockburst in negative coal pillar roadway induced by dynamic load disturbance

Year: 2025

Type: article

Abstract: The negative coal pillar roadway arrangement has been widely adopted in rockburst-prone mines across the country, demonstrating effectiveness in mitigating the rockburst risk associated with roadways along the gob. However, an unexpected rockburst incident occurred in the negative coal pillar roadway during the mining of the 17-seam coal gob-side fully mechanized caving face at Junde Coal Mine. In response to this incident, we conducted a comprehensive investigation of the rockburst damage characteristics of the negative coal pillar roadway in the context of dynamic load disturbances. Our approach utilized a multifaceted methodology, incorporating field measurements, numerical simulations of particle flow, and theoretical analysis. This enabled us to clarify the underlying mechanisms of rockbursts in negative coal pillar roadways induced by dynamic load disturbances and to propose a methodology for identifying rockburst hazards in such roadways. The findings of this study can be summarized as follows: We analyzed the movement and evolution characteristics of surrounding rock in the negative coal pillar roadway and proposed a risk criterion for rockbursts under dynamic load disturbances based on the ejection velocity of coal and rock bodies and the maximum radial displacement of the roadway. A rockburst damage calculation model for the negative coal pillar roadway under dynamic load disturbances was developed based on energy attenuation theory and rock dynamics. We derived the displacement damage engineering criterion and the dynamic damage criterion for the coal body in the negative coal pillar roadway under dynamic load disturbances, and proposed a method for identifying rockburst risk in this context. From a displacement perspective, the radial displacement of the roadway depends on the stress of the original rock, the angle of internal friction, and cohesion, which reflect the inherent strength of the rock, support resistance, and dynamic load. From an energy perspective, the ejection velocity of the coal body in the roadway is influenced by the energy of the mining shock, the distance from the mining shock to the negative coal pillar roadway, the energy attenuation coefficient, the range of the plastic zone, and the energy-absorbing effect of the roadway support assemblies. We proposed three targeted prevention and control measures, focusing on the generation of the vibration source, the propagation path of the vibration wave, and the mechanism of vibration wave disaster. These measures are designed to reduce the risk of rockbursts in negative coal pillar roadways subjected to dynamic load disturbances. The first measure involves quantifying the critical width of the pressure relief protection zone. The second measure addresses the over-support of the negative coal pillar roadway. The third measure entails pre-cracking and blasting of the roof plate.

Source: Chinese journal of rock mechanics and engineering

DOI: 10.3724/1000-6915.jrme.2024.0907