Study On The Long-term Pillar Stability Of Room And Pillar Based On Creep Theory

With the depth development of the theory of rock mechanics, it’s discovered that coal pillar stability not only associate with coal pillar strength and size, it also inseparable with the time factor. Especially in the study of the long-term stability of the coal pillar, the time factor must be taken into account. Therefore, it is the inevitable requirement of coal mine production safety that creep theory is introduced to the study of the long-term stability of the coal pillar.Relying on room-and-pillar coal pillar design engineering of Danhou mine, FLAC-3D numerical simulations is used to determine the width of the coal pillar and optimize the mining plan. Through single specimen stepwise incremental loading (namely Chen loaded) experiments, Creep curve, the stress-strain curve and strain over time variation curve are plotted. Then model rheological parameters and the correlation coefficient are determined by fitting creep test curves and classic creep model curve. Long-term stability of the coal pillar is calculated in the case of known the coal pillars parameters and coal pillar width based on empirical models.Experimental study found that the Danhou mine coal-and-rock specimen has good creep properties, it has the higher fitting degree with the empirical model, the three non-attenuation creep process can be reflected. However, there are certain limitations that experimental coal-and-rock creep parameters directly applied to the coal pillar because of the conditional diversity characteristics limit. On the base of size effect, experimental creep empirical formula combined cumulative damage theory to determine the role factor of the long-term stability of the coal pillar. It provides a theoretical basis for the creep theory-based long-term coal pillar stability dependencies computational analysis.