Experimental study of shear wave velocity in unsaturated tailings soil with variant grain size distribution

This study presents experimental tests on the influence of grain size distribution on the shear wave velocity (V-s) of unsaturated tailings. Combined with other scholars' experiments and research methods, more than 40 unsaturated samples from the Xiaodae copper tailing dam with four different grain size distributions were tested on a tri-axial testing instrument with bending elements at different effective stresses and void ratios. The test results showed that the soil water characteristic curve of the unsaturated tailing soils is similar to that of other sandy soils, and V-s is strongly related to effective stress, grain size, and void ratio. The V-s empirical formula is obtained with the characteristic parameters of the grain size distribution by fitting the experimental data. The fitting results showed that parameter C-u has a better correlation than D-50 and C-c, under the samples. The predicted V-s empirical formula can also be applied to the Xiaodae field test (drilling Vs test). Finally, the similarities and differences of the V-s (G(max)) fitting formulas with those from other scholars are compared in terms of the choice of the parameters of the grain size characteristics. The coefficients of variation of D-50 and C-u can be used as the basis for selecting two parameters to characterize the particle size in fitting V-s (G(max)) to obtain a better predicted effect and application efficiency. (C) 2019 Elsevier Ltd. All rights reserved.