The Spatial Gradation Characteristics and Intensity Evolution Law of Mine Dump

Most of the mine dumps have very prominent slope stability problems. In this paper, by analyzing the gradation characteristics and spatial distribution characteristics of the discharged particles, the functional relationship between the characteristic particle size parameters and the relative height of the dump was obtained. Based on Dagushan environmental and climate characteristics, the indoor triaxial shear test under freeze–thaw cycle conditions was used to study the strength characteristics of discharged particles. The experimental results showed that the particle size of the dump presented a horizontal stratification phenomenon of “small at the top and large at the bottom,” with the content of fine particles (<20 mm) increasing from 13.83% at the bottom to 59.06% at the top. With the increase of the number of freeze–thaw cycles, the damage strength decreased gradually. Under the confining pressure of 50 kPa, the failure strength decreased from 335.8 kPa (0 cycles) to 160.5 kPa (24 cycles), and when the freeze–thaw cycle reached 24 times, the damage strength became stable. The increase of confining pressure in a certain range (50–150 kPa) can effectively inhibit the deterioration effect of freeze–thaw cycle on the damage strength of waste: the failure strength reduction rate at 150 kPa was 26.89% (24 cycles) compared with 52.20% at 50 kPa.