Ultra-fine tailings cemented paste backfill (UCPB) exhibits special rheological characteristics with the effect of an ultrasonic sound field. In this study, in order to explore the thickening effect of slurry under ultrasonic wave action, we examined the rheological properties with ultrasonic wave tests of UCPB and the rheological properties after ultrasonic wave tests of UCPB. We found that the rheological curve of the slurry changed; the Herschel–Bulkley (HB) model in the initial state transformed into the Bingham model under the action of ultrasound. Ultrasonic waves have a positive effect on reducing slurry viscosity and yield stress. The rheological test of the slurry with ultrasonic wave action had a positive effect on significantly reducing the apparent viscosity and initial yield stress of slurry with a 62% mass concentration. The rheological test of slurry with ultrasonic wave action and the rheological test after ultrasonic wave action both have positive effects on reducing the viscosity and yield stress of the slurry with a 64% to 68% mass concentration; the overall effect of reducing the viscosity and yield stress of UCPB is greater after ultrasonic wave action of UCPB.

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In existing tailings-discharge (TD) systems, the feeding, settlement and discharge are conducted alternately in multiple vertical silos. A model of continuous TD, which differs from the aforementioned model, is proposed to solve the problems of the high fluctuation in underflow concentration and the relatively low, unstable actual discharge concentration in vertical tailings silos. The continuous discharge of the tailings in the silo was simulated using computational fluid dynamics software. In the simulation, four slurry-underflow conditions were selected to record the corresponding compression-region height and the variation of the slurry concentration with that height based on preset monitoring curves. In addition, a relationship between the tailings volume fraction and silo height was obtained by fitting, and a predictive model was proposed for the change in the volume fraction of the underflow tailings with the compression-region height. A new working mode of the discharge system in the backfilling system was proposed, and fluent software was used to simulate the new discharge system. Industrial field tests verified the reliability of the results of the numerical simulations. It greatly improved the work efficiency of the vertical silos as it reduced the number of working vertical silos, omitted the process of completely discharging and charging the silos, and simplified the preparation of the slurry materials. With these advantages, the model guaranteed the filling efficiency and quality. Applying the proposed model of continuous TD for vertical silos effectively overcame the technical problems facing the existing TD systems in mines.

A continuous tailing discharge model is proposed for solving the problems of high fluctuation in underflow concentration and low, unstable actual discharge concentration in vertical tailing silos. On the basis of the mass balance equation, a mathematical model for continuous tailing discharge is derived, and a partial differential equation related to the height of the tailing silo in the compression area and tailing slurry concentration is obtained. The effective solid stress equation and the solid flux equation can be obtained from the results of centrifuge tests and intermittent sedimentation tests. The volume concentrations of underflow corresponding to various heights of tailing surfaces are simulated by using fluid mechanics software under dynamic balancing conditions. The results of the simulations are highly similar to those calculated by the derived mathematical model of continuous tailing discharge, and the results of the industrial test are also closely related to the results of the differential equation, thereby verifying the accuracy of the proposed discharge model.

Driven by the commitment of achieving peak carbon dioxide emissions before 2030 and carbon neutrality before 2060, China is promoting the optimization of its energy and industry structures. In the electricity supply industry, a large number of different types of sophisticated large and giant hydropower stations are planned or being constructed in western China. In future decades, hydropower may take the dominant position in China’s electricity supply. Rock fracturing behavior plays a vital role in geotechnical hazard prevention and geotechnical engineering design. With the construction of hydropower stations, rock mechanics investigation will be of great concern. This study presents a hybrid model that coupled the finite element method and peridynamic theory to simulate the indirect tensile strength of marble. Sensitivity analyses of the loading rate, mesh size, and fracture energy release rate are performed. The numerical results indicate that both the loading rate and mesh size significantly affect the numerical representation of rock properties. After the calibration of the fracture energy release rate, Brazilian tensile strength modeling is successfully conducted, and the numerical results are consistent with the experimental results.