Resumo

WANG, W.; JIANG, T.; WANG, Z.  e  REN, M.. A analytical model for cover stress re-establishment in the goaf after longwall caving mining. J. S. Afr. Inst. Min. Metall. [online]. 2017, vol.117, n.7, pp.670-683. ISSN 2411-9717.  http://dx.doi.org/10.17159/2411-9717/2017/v117n7a9.

Cover stress re-establishment has a significant influence on the deformation and development of permeability in the fractured rock mass, which control the surface subsidence and water inflow after longwall caving mining. This paper reviews previous studies on cover stress re-establishment in the goaf after coal mining, and proposes a new analytical model based on the stress-strain characteristics of the caved rock mass and the voussoir beam theory. A scale model test is also conducted to study the cover stress re-establishment based on a coal mining case. A function was derived for cover stress re-establishment in the goaf, which can be approximately described as a logarithmic function and which agreed well with two completely re-established monitoring sites from the scale model test. The scale model test also indicated that cover stress reestablishment presents a hysteresis phenomenon. A 'stress balance' model was built for calculating the distance of cover stress re-establishment in the goaf, and the result from the model was lower than the results from the previous two methods. The cover stress re-establishment function and the 'stress balance' model will be of great significance for a better understanding of the stress distribution in the goaf.

Palavras-chave : longwall mining; goaf; caving; fracturing; cover stress re-establishment; calculation model.

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