Research On Mechanical Properties Of Slag Phosphate Tailings Clay Mixture

In this paper,the mixture of phosphorus tailings and clay as the research object,carried out a series of experiments,the research results and conclusions are as follows:(1)The optimal water content of phosphorus tailings is 30 % and the maximum dry density is 1.55 g / cm3.the optimal water content of phosphorus tailings is higher than that of clay,and the maximum dry density is lower than that of clay.The direct shear test of phosphorus tailings shows that the internal friction angle of phosphorus tailings is 39.3 and the cohesion is 46.826 kpa.The compression coefficient of phosphorus tailings is 0.41 MPa-1,the compression modulus is 3.5 MPa,according to the compressibility classification of soil,the phosphorus tailings belong to medium compressibility soil.(2)Mixing the content of 5 %,10 %,15 %,20 % phosphorus tailings into clay,the relative density of the mixture is 2.728,2.716,2.706,2.688.The proportion of phosphorus tailings and clay is 2.589,2.735.It can be seen that with the increase of the content of phosphorus tailings,the relative density of the clay mixture decreases,and the trend of decrease is almost linear.(3)Based on the above pure phosphorus tailings test,the water content is 20 %,the dry density is 1.55 g / cm3 and 1.65 g / cm3,the mixing amount is 5 %,10 %,15 %,20 % of phosphorus tailings clay mixture is direct shear test,compression test,triaxial test.In the direct shear test,the cohesion increases nonlinearly with the addition of phosphorus tailings,and the internal friction angle decreases linearly with the increase of phosphorus tailings.Under the same dry density,the larger the dry density,the smaller the internal friction angle decreases.with the increase of phosphorus tailings,the shear strength of clay is enhanced.In the compression test.The dry density is 1.65 g/ cm3,5 %,10 %,15 % and 20 % respectively.the compression coefficient is: 0.0051,0.0043,0.0036,0.0025;The compression index is 0.0031,0.0021,0.0015,0.002;The compression modulus is 350 MPa,423 MPa,491 MPa,702 MPa,respectively.The compression coefficient of clay mixture decreases with the increase of phosphorus tailings addition,the compression index first increases and then decreases.when the content of phosphorus tailings is 15 %,the compression index of different dry density phosphorus tailings reaches the minimum.In triaxial test,the main stress difference of dry density clay mixture is small,and the stress-strain relationship curve of phosphorus tailings clay with dry density of 1.65 g / cm3 appears less obvious strain softening phenomenon.when the dry density is 1.55 g / cm3,strain softening occurs only under low confining pressure.The cohesion of different phosphorus tailings clay increases with the increase of the content of phosphorus tailings,and the internal friction angle increases with the addition of phosphorus tailings.when the dosage is 20 %,theincrease of the cohesion is the largest.It can be seen from the experiment that the incorporation of phosphorus tailings has a better improvement on the mechanical properties of clay,which provides a reference for the reuse of phosphorus tailings.