Research On The Mechanical Characteristics Of The Tailing Medium Sand From Dagushan Tailing Dam

Geomaterials,such as sand,are mainly composed of a large number of particulate matters.From the micro level,there is the uneven distribution in terms of the shape,size and location of the particles.From the macro level,it is displayed in the mechanical behavior,such as compressive hardening,dilatancy,and anisotropy.Although many scholars have done a lot of research on the mechanical behavior of sand,there is little research on the mechanical characteristics of tailing under different stress paths.On the basis of the project of the tailing medium sand from Dagushan tailing dam,the variation law of stress-strain relationship under different stress path are gotten by indoor triaxial test.The main work and conclusions carried out in this paper:1.The paper discusses and analyses the research status on the mechanical property of sandy soil and tailing under different stress paths.2.Test using triaxial apparatus of SLB-1,conduct a undrained trial test with consolidated and unconsolidated for tailing medium sand from Dagushan tailing dam under different confining pressure,then draw the stress-strain curve and stress path curve.Test revealed that the tailing medium sand consolidated have the higher strength than unconsolidated under the same confining pressure.It means that degree of consolidation have significant impact on strength of tailing medium sand.And different confining pressure have effect on the tailing medium sand under the same stress path.In the consolidated-undrained test,pore water pressure is firstly increased to peak then decreased and create negative pressure under different confining pressure.3.Using the system of triaxial SLB-1,design a experiment for tailing medium sand under different stress paths.According to the laboratory test,gotten the stress-strain curve of tailing medium sand from Dagushan tailing dam.On the base of the stress-strain curve,there have three strength paths are reflect the strain softening characteristics.The stress path have significant effect on the strength and deformation of tailing medium sand.In the conventional undrained triaxial compression test,pore water pressure is firstly increased to peak then decreased and create under different confining pressure.And only the consolidated-undrained triaxial test will create negative pressure.4.The paper calculated the parameters of tailing medium sand under different strength paths of Duncan-Chang model.5.The stress-strain curve of tailing medium sand is in accord with the power function form under the same path of principal stress ratio.