Journal Article

Non-orthogonal Failure Behavior of Roadway Surrounding Rock Subjected to Deep Complicated Stress

Liu, Haiyan, Zuo, Jianping, Xu, Chengyi, Zhu, Fan, Ma, Zongyu

2023

Overview

Based on the characteristics of real stress distribution in coal mining, the evolution law of plastic zone shape and spatial position were investigated. The stress model of roadway with non-orthogonal state of in-situ stress and mining-induced stress was constructed. The boundary equation of the roadway plastic zone under in-situ stress deflection was deduced. Additionally, the evolution mechanism of the roadway plastic zone was analysed. We found that the shape and spatial position of the roadway plastic zone are jointly determined by in-situ stress deflection angle α, mining-induced stress concentration coefficient K, and equivalent lateral pressure coefficient η′ when the mechanical parameters (rock cohesion c; internal friction angle φ) were fixed. Specifically, the plastic zone experiences the cyclic evolution phenomenon, where the plastic zone shape varies from petal–ellipse–circle–ellipse–petal shapes in morphology. In this study, we expound the general evolution law of roadway plastic zone under different geological, working conditions and mechanical parameters. The main controlling factors and mechanism of the shape and spatial position evolution of the plastic zone are revealed. A numerical model was established to study the evolution law of plastic zone during the change of corresponding parameters. The results show that the traditional method of predicting the shape of plastic zone by lateral pressure coefficient is inaccurate. The plastic zone distribution calculated using this method was compared with the roadway deformation measured in 1305 bottom drainage roadway of Hudi mine, and the comparison results were in good accordance. The results of this study have certain universality, and enrich the understanding of the roadway plastic zone. It can provide theoretical reference for roadway excavation and support design under different geological and in-situ stress conditions.HighlightsThe non-orthogonal failure behavior of the roadway with the change of complicated stress state is revealed.Plastic zone experiences the cyclic evolution phenomenon, where the plastic zone shape varies from petal-ellipse-circle-ellipse-petal shapes in morphology.Main controlling factors and mechanism of the shape and spatial position evolution of the plastic zone are summarized.The unsymmetrical failure mechanism of roadway under non-orthogonal stress state is revealed.

• Publisher: Springer Nature B.V
• Subject: Circles (geometry) / Coal mining / Deflection / Deformation / Evolution / Excavation / Failure mechanisms / Geology / Internal friction / Lateral pressure / Mathematical models / Mechanical properties / Mining / Morphology / Numerical models / Parameters / Petals / Plastic zones / Plastics / Roads & highways / Rocks / Shape / Stress / Stress concentration / Stress distribution / Stress state / Working conditions / Zonal distribution