Abstract: As a green and environmentally friendly grouting material,tailings concretion has been widely used in mine grouting and water plugging technology,and its permeability characteristics are very important for the safe mining of mines. Based on this,this study produced tailings concretion samples with different cement contents,and used the rock permeability test system to carry out the seepage-stress coupling permeability test of tailings concretion under different osmotic pressures and confining pressures. The evolution law of permeability characteristics of tailings concretion under seepage-stress coupling is clarified. Combined with the low field nuclear magnetic resonance system,the evolution mechanism of permeability characteristics of tailings concretion body is revealed. The results show that:① The porosity,flow rate and permeability evolution of the tailings concretion body are highly consistent. It shows significant stage characteristics,which can be divided into rapid saturation stage,shrinkage and flow suppression stage and stable seepage stage. ② The evolution law of porosity,flow velocity and permeability of tailings concretion is negatively correlated with the change of cement content and confining pressure,and positively correlated with the change of osmotic pressure. ③ The change of pore structure is the key factor that dominates the evolution of permeability characteristics of tailings concretion. With the increase of osmotic pressure,the proportion of medium pores and large pores increases,and the permeability increases. With the increase of confining pressure,the proportion of micropores increases,and the permeability decreases. The research results can provide theoretical guidance for grouting engineering. 

Key words: tailings concretion,seepage-stress coupling,permeability,nuclear magnetic resonance