<p>The evolution law of roadway plastic zone under three-dimensional stress field is of great significance to roadway stability control. The strength criterion is the basis for judging the surrounding rock failure. According to the rock energy theory, the energy strength criterion is established. Based on energy strength criterion and considering the roadway axial stress, the boundary equation of roadway plastic zone under three-dimensional stress field is derived. The results show that the distortion energy required for rock failure is positively correlated with confining pressure. The energy strength criterion can describe the strength characteristics of rock well and reflect the Lode angle effect and hydrostatic pressure effect. The plastic zone shape is mainly determined by the lateral pressure coefficient <i>λ</i>. When <i>λ</i> gradually increases, the plastic zone shape evolution shows ‘circular→elliptical→butterfly-shaped’. Axial stress mainly affects plastic zone size. The closer the axial stress is to horizontal stress, the smaller the plastic zone size. When the stress environment and roadway size are constant, the main factors affecting plastic zone expansion are the uniaxial compressive strength of coal-rock mass of roadway and the material parameter in the energy strength criterion. The plastic zone size decreases with the increase of the two.</p>

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Elastoplastic boundary solution of surrounding rock of circular roadway based on energy theory

  • Hong-tao Liu,
  • Qin-yu Liu

摘要

The evolution law of roadway plastic zone under three-dimensional stress field is of great significance to roadway stability control. The strength criterion is the basis for judging the surrounding rock failure. According to the rock energy theory, the energy strength criterion is established. Based on energy strength criterion and considering the roadway axial stress, the boundary equation of roadway plastic zone under three-dimensional stress field is derived. The results show that the distortion energy required for rock failure is positively correlated with confining pressure. The energy strength criterion can describe the strength characteristics of rock well and reflect the Lode angle effect and hydrostatic pressure effect. The plastic zone shape is mainly determined by the lateral pressure coefficient λ. When λ gradually increases, the plastic zone shape evolution shows ‘circular→elliptical→butterfly-shaped’. Axial stress mainly affects plastic zone size. The closer the axial stress is to horizontal stress, the smaller the plastic zone size. When the stress environment and roadway size are constant, the main factors affecting plastic zone expansion are the uniaxial compressive strength of coal-rock mass of roadway and the material parameter in the energy strength criterion. The plastic zone size decreases with the increase of the two.