| After ore dressing,a large amount of tailings sand is produced.As an industrial solid waste,it not only occupies a large amount of land,pollutes the environment,but also brings safety hazards to production and life.Therefore,the static and dynamic properties of tungsten-molybdenum tailings sand are studied,which provides a basis and basis for comprehensive utilization.In this paper,the static and dynamic properties of clay-modified tungsten-molybdenum tailings,cement-modified tungsten-molybdenum tailings and lime-modified tungsten-molybdenum tailings are studied in laboratory tests.The main work and achievements are as follows:Through a series of soil mechanics tests,some basic physical and mechanical indexes of tungsten-molybdenum tailings are measured,which provides a reference for the study of subsequent dynamic characteristics.The GDS dynamic triaxial test system was used to carry out the consolidation drainage shear test on the tungsten-molybdenum tailings sand and the modified tungsten-molybdenum tailings under different confining pressure conditions,and the static mechanical indexes were measured.The results show that the strength of clay-modified tungsten-molybdenum tailings is not obvious,while the cement and lime-modified tungsten-molybdenum tailings have obvious effect on the strength improvement;the damage of cement-modified tungsten-molybdenum tailings is mostly brittle failure.The composition and structure of the modified tungsten-molybdenum tailings were microscopically analyzed by scanning electron microscopy and X-ray diffraction analysis.Through the study on the microstructure of cement-modified tungsten-molybdenum tailings sand,it is found that the cement-modified tungsten-molybdenum tailings contain interconnected plate-like and needle-like structures.According to the XRD pattern analysis,the mechanism of the clay-modified tungsten-molybdenum tailings is that the self-adhesive bonds the sand grains;and the mechanism of the lime-modified tungsten-molybdenum tailings is the crystallization and carbonization.The GDS dynamic triaxial apparatus was used to carry out single-stage loading test on the modified tungsten-molybdenum tailings.The dynamic strength analysis of tungsten-molybdenum tailings and modified tungsten-molybdenum tailings under different consolidation conditions was carried out,and the tungsten-molybdenum tail was obtained.The dynamic strength curve and the relationship between dynamic stress and cyclic stress of ore and modified tungsten-molybdenum tailings are analyzed,and the variation law of dynamic strength and dynamic stress ratio is analyzed.The fitting relationship of dynamic strength is given.Curve,the dynamic shear strength index is obtained.The GDS dynamic triaxial apparatus was used to carry out the step-by-step loading test of the modified tungsten-molybdenum tailings.The dynamic stress-dynamic strain relationship of the tungsten-molybdenum tailings and the modified tungsten-molybdenum tailings under different consolidation conditions was analyzed and based on Hardin.The-Drnevich elastic model fits the dynamic stress-dynamic strain curve and obtains the relevant parameters in the model.Based on the dynamic stress-dynamic strain relationship of cement modified tungstenmolybdenum tailings,the dynamic elastic modulus is calculated.By analyzing the variation law of dynamic elastic modulus with dynamic strain,the relationship curve between dynamic elastic modulus and dynamic strain is established.Based on the fitting results of stress-dynamic strain,the formula for calculating the maximum dynamic elastic modulus of cement-modified tungstenmolybdenum tailings is obtained,and the dynamic axial strain,dynamic shear strain,elastic modulus and shear modulus are used.The relationship is obtained by the maximum dynamic shear modulus.The relationship between the damping ratio and dynamic strain of tungsten-molybdenum tailings and cement-modified tungsten-molybdenum tailings is obtained by using the formula of equivalent damping ratio in soil mechanics. |
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