| With the increasing exhaustion of mineral resources,it is a key issue to solve the resource exploitation and utilization of mineral resources.The large-scale application of the surface deposit of tailings and the rapid development of the filling equipment have promoted the development of the whole tailings dry pile filling.The size and stability of the natural repose angle of full tailings filling in dry stowing mining technology is very important to realize efficient and continuous mining.This paper carries out experimental research on the natural repose Angle of the whole tailings dry pack filling body.The main research contents are as follows:(1)Analyze the basic structural features of granular materials,the basic physical properties,particle gradation,permeability coefficient,mineral composition and other parameters were determined.(2)Through the indoor direct shear test,two parameters of concentration(83%,85%,87%,89%,91%)and cement content(0%,3%,5%,7%,9%)were used as influencing factors,to carry out experiments on the influencing factors of the flow characteristics and shear strength of all-tailed sand dry heap fillings.The results show that:as the concentration of dry packs increases,the cohesion increases first and then decreases,and the internal friction angle increases first and then tends to be gentle;With the increase of cement content,the increase of cohesion is greater and the change of internal friction angle is smaller.Through the shear force-shear displacement curve of the dry pack,the shear strength model of the whole tail sand dry pack was constructed,and the mechanism of the adhesive strength of the whole tail sand dry pack was revealed.(3)The natural accumulation angle and slump test of the filling body of the whole tailings dry pile were carried out,and the change rule of the natural accumulation angle and slump of the dry filling body was obtained under the condition of different concentration and cement content.The results show that:as the concentration increases,the natural accumulation angle decreases and then increases;with the increase of cement content,the natural accumulation angle is decreasing and the decrease is smaller;Slump corresponds exactly to the results of the natural rest test.The relative movements of particles in filling and sinking process of dry-pile backfills filled into goafs were studied.It was found that the movement of particles in filling process mainly depended on the nature of the interface formed between continuous-slippingfilling material and filling-slope surface.And the particles in the dry heap filling are in a periodic motion state.The pores of the filling body are gradually filled,the overall stability is enhanced,and a certain natural repose angle can be maintained without collapse.(4)An indoor simulation test was conducted for the deformation and failure of the backfill slope of the whole tailing sand dry dump.The variation characteristics of the profile curve of the backfill slope were analyzed,and the grain drag and push movement characteristics were studied.The theoretical calculation of the particle movement on the backfill slope of the dry heap was carried out,and the starting conditions for the sliding and rolling of the particles on the slope of the filling body were deduced.The results show that:the rolling of the particles mainly depends on the size of the external force,and the internal friction angle between the particles and the angle between the slope and the horizontal plane have a great influence on the anti-sliding coefficient of the particles.On the basis of experiments and theoretical derivation,the damage mechanism of slope slumping,slipping,and shearing of dry-piled backfill slopes is proposed.The failure of the slope of the dry dumped backfill is the result of the internal and external factors.The internal cause is to maintain the integrity of the system and the external cause triggers,and the stability of the whole tailings dry pile is determined. |
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