Abstract
Mine disasters, as associated problems in the development of coal resources, always threaten the life safety of miners and the production safety of enterprises. In coal roadway excavation, the coal in front of the excavation face is in a state of concentrated stress and the deformation is serious. The instability of the coal seam under stress is an important cause of the occurrence of coal and gas outburst. Thus, knowing the mechanical characteristics of surrounding rock in front of the working face is of great significance for deep understanding and effective prevention and control of coal-rock dynamic disasters. By analyzing the characteristics of stress evolution and deformation and failure in front of the heading face, the analytical solution of plastic region distribution in front of the heading face is obtained. According to the established mechanical model, MATLAB numerical calculation software is used to analyze different examples. The influence of different mechanical parameters on the stress state of the working face is studied. The influence parameters of the morphological characteristics of the plastic region are determined, and the change law and characteristics of the plastic region in front of the working face are studied. At the same time, through the characteristics of stress field, the working face dynamic risk assessment of coal and rock dynamic disaster can be realized, which can provide a powerful guarantee for the prevention and control of gas dynamic disasters in deep mine.
Highlights
From 2006 to 2019, a total of 10,278 accidents occurred in coal mines in China, resulting in 29,312 deaths
Among all kinds of accidents, the number of roof accidents is nearly twice that of gas accidents, while the death toll of gas accidents is more than twice that of roof accidents, which is close to the sum of the death tolls of the other five types of accidents. erefore, the gas accident is the biggest threat to the life safety of miners
When the peak stress exceeds the strength of the rock mass, the elastic energy and gas pressure accumulated in front of the working face are suddenly released, resulting in gas outburst. erefore, studying the mechanical characteristics of surrounding rock in front of the excavation is of great significance to the accuracy of coal and gas outburst prediction
Summary
From 2006 to 2019, a total of 10,278 accidents occurred in coal mines in China, resulting in 29,312 deaths. Coal and gas outburst accidents mainly occur in the driving face of coal roadway; in essence, it is a process of coal-rock mass instability under mining disturbance, and the redistribution of stress in front of the working face caused by mining operation is the source of this accident and its evolution. Luan et al [8] studied the mining stress field by the method of numerical simulation and field measurement; their results indicated that the abutment pressure field in front of the coal wall is not distributed symmetrically along the middle of the working face. Zhang et al [12] studied the failure laws and characteristics of coal and rock mass with the theory of “strong and soft face” and obtained the distribution range of plastic region in front of working face. It is still necessary to carry out studies on the dynamic response law of coalrock mass in front of the working face along with the tunneling operation based on the above work. is work will help improve the monitoring and early warning of coal and rock dynamic disasters and promote coal mine safety production
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