Experimental Study On Mechanical Properties Of Tailings Dry Body

The successful application of tailings dry-stack technology and filling technology at domestic and international mines brings hope to the treatment of mine gobs and disposal of tailings.The tailings dry dump technology is applied to the mine filling,and the treated tailings are prepared into dry tailings backfills and transported to the underground goafs.This not only solves the problem of tailings accumulation processing but also enables tailing mining,Filling of empty areas,maintaining the stability of goafs and realizing efficient continuous mining in mines.The paper takes the tailings dry bulk body as the research object and conducts research.The main research contents:(1)The basic parameters such as basic physical properties,gradation,and mineral composition of the filling materials were tested and analyzed to provide certain reference for subsequent mechanical properties tests and settlement tests of dry tailings backfill bodies.(2)The mechanical properties of the dry bulk filling of the tailings were studied using a strain-type direct shear meter.The results showed that the dry filling material of the tailings showed obvious linear elastic properties;the internal friction angle of the dry tailings of the tailings mainly depended on the mass concentration.The size and internal friction angle increase with the increase of mass concentration,and the mass concentration is 85%-87%.The internal friction angle increases the most;the cohesion force shows an upward trend with the increase of cement content and the increase of mass concentration.83%-85%maximum increase in cohesion(3)According to the actual size of the mine house,design the test model according to 1:100 scale,Study on Settlement Regularity and Influencing Factors of Dry Dump Tailings Filling by Indoor Similar Simulation Test.The settlement of dry tailings backfills shows a power function with time,Total sedimentation depends mainly on mass concentration,cement content has less effect on total sedimentation.(4)Study on mechanical properties of dry tailings backfill after coagulation based on orthogonal design.According to the range analysis,the main and secondary factors affecting the compressive strength and elastic modulus of dry tailings backfill are:cement content>curing time>mass concentration.The primary and secondary factors of internal friction angle are curing time>cement content>mass concentration,cohesion force primary and secondary factors are cement content>curing time>mass concentration.The compressive strength increases with increasing cement content,decreases with increasing mass concentration,and increases with increasing curing time.The elastic modulus increases with increasing cement content,decreases with higher mass concentration,and increases with increasing curing time.The internal friction angle decreases with the increase of cement content,increases with the increase of the mass concentration,and decreases with the increase of the curing time.The cohesive force increases with the increase of cement content,decreases first and then increases with increasing mass concentration,and increases with the increase of curing time.The dry tailings of the tailings contains less cement,high mass concentration,and very little hydration products,so it is impossible to coagulate the tailings particles.(5)Through SEM microstructural analysis,the cement hydration products ettringite and hydration calcium silicate are important hydration products that form the tailings dry bulk strength.The ettringite and C-S-H gelation act together to form a network skeleton,densely enveloping the particles in the tailings to form a dense microstructure,thereby improving the solid particle consolidation effect.