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Geomechanics and Engineering
  Volume 14, Number 5, April10 2018, pages 439-451
DOI: http://dx.doi.org/10.12989/gae.2018.14.5.439
 


Study of stability and evolution indexes of gobs under unloading effect in the deep mines
Jianxin Fu, Wei-Dong Song and Yu-Ye Tan

 
Abstract
    The stress path characteristics of surrounding rock in the formation of gob were analysed and the unloading was solved. Taking Chengchao Iron Mine as the engineering background, the model for analysing the instability of deep gob was established based on the mechanism of stress relief in deep mining. The energy evolution law was investigated by introducing the local energy release rate index (LERR), and the energy criterion of instability of surrounding rock was established based on the cusp catastrophe theory. The results showed that the evolution equation of the local energy release energy of the surrounding rock was quartic function with one unknown and the release rate increased gradually during the mining. The calculation results showed that the gob was stable. The LERR per unit volume of the bottom structure was relatively smaller, which mean the stability was better. The LERR distribution showed that there was main energy release in the horizontal direction and energy concentration in the vertical direction which meet the characteristics of deep mining. In summary, this model could effectively calculate the stability of surrounding rock in the formation of gob. The LERR could reflect the dynamic process of energy release, transfer and dissipation which provided an important reference for the study of the stability of deep mined out area.
 
Key Words
    deep mine; gob; unloading; local energy release rate; cusp catastrophe
 
Address
Jianxin Fu: 1.) School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China
2.) School of Engineering, University of Tokyo, Tokyo 110-0008, Japan

Wei-Dong Song and Yu-Ye Tan: School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China
 

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