Geomechanics and Engineering

Volume 18, Number 1, 2019, pages 21-27

DOI: 10.12989/gae.2019.18.1.021

A stress model reflecting the effect of the friction angle on rockbursts in coal mines

Jinyang Fan , Jie Chen , Deyi Jiang , Jianxun Wu , Cai Shu , Wei Liu

Abstract

Rockburst disasters pose serious threat to mining safety and underground excavation, especially in China, resulting in massive life-wealth loss and even compulsive closed-down of some coal mines. To investigate the mechanism of rockbursts that occur under a state of static forces, a stress model with sidewall as prototype was developed and verified by a group of laboratory experiments and numerical simulations. In this model, roadway sidewall was simplified as a square plate with axial compression and end (horizontal) restraints. The stress field was solved via the Airy stress function. To track the \"closeness degree\" of the stress state approaching the yield limit, an unbalanced force F was defined based on the Mohr-Coulomb yield criterion. The distribution of the unbalanced force in the plane model indicated that only the friction angle above a critical value could cause the first failure on the coal in the deeper of the sidewall, inducing the occurrence of rockbursts. The laboratory tests reproduced the rockburst process, which was similar to the prediction from the theoretical model, numerical simulation and some disaster scenes.

Key Words

failure; numerical analyses; plasticity; rock; triaxial tests

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