Abstract
The distribution of a plastic zone ahead of a gateroad plays a significant role in maintaining the long-term stability of mining spaces. For a long time, the principal stress field such as the values, the direction, etc. have been observed to have impacts on plastic zone development, but has not been looked into deeply and systematically. To this end, the influence of principal stress field including the maximum principal stress (P1), the angle between the P1 direction and the Z-axis (α), the minimum principal stress (P3), and the ratio of maximum principal stress to minimum principal stress (P1/P3) on the expansion of the plastic zone ahead of the gateroad is investigated by the (Fast Lagrangian Analysis of Continua) FLAC3D models. The results show that: (1) The plastic zone volume increases first and then decreases with the increase of α, and the direction of butterfly-shaped plastic zone ahead of gateroad is rotating with the evolution of α. (2) The plastic zone volume ahead of excavation face increases gradually with the increase of P1/P3. Mutagenicity of butterfly-shaped plastic zone occurs ahead of the gateroad under a certain value of P1/P3. (3) With the increase of P1 and decrease of P3, the plastic zone volume is of exponential growth. The plastic zone volume approaches infinity when the critical value of maximum principal stress ([P1]) and the minimum principal stress ([P1]) is obtained. (4) The study of the effect of principal stress field on the expansion of plastic zone ahead of the gateroad is helpful for revealing the mechanisms of coal and gas outbursts. The critical stress state of butterfly-shaped plastic zone mutagenicity ahead of the gateroad can be used as an important indicator for assessing the risk of coal and gas outburst. The research can also guide the prevention of coal and gas outburst ahead of the gateroad.
Highlights
A gateroad is an essential access or opening to underground mining sites, which plays a significant role in transportation and ventilation [1,2]
It shows that the plastic zone is mainly located
Implications for Coal and Gas Outburst Induced by the Expansion Plastic Zone ahead of Gateroad
Summary
A gateroad is an essential access or opening to underground mining sites, which plays a significant role in transportation and ventilation [1,2]. The stability of the roadway under the complex stress field is studied and the elliptical-shaped plastic zone of the gateroad is obtained [10,11]. Zhao et al (2014) investigated the stress distribution and deformation characteristics of gateroad surrounding rock under different stress conditions. Lu et al (2010) analyzed the distribution range and shape of the plastic zone under different levels of tectonic stress, vertical pressure, cohesion, and friction angle of the surrounding rock by theoretical formula, numerical simulation, and field measurements [16]. The theoretical study of the distribution characteristics of the stress field around a circular cavity was performed and the directional sharp-point failure mechanism was determined by analyzing the stress destructive power using the three elements of the.
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