Abstract: The control of hidden hazards of large-scale high tailings ponds is an important task and key project to contain major accidents during the "13th Five-Year Plan" period. Key issues closely related to this research topic are the evolution of the meso-structure and macro-mechanical properties of tailings materials under high stress, the sedimentary regularity of large tailings dams, and the theory of degradation of high tailings dams under complex conditions. In order to reveal the meso-structure characteristics of the tailings, the tailings materials can be screened by optical microscope, electron microscope scanning, and CT scanning. In this paper, a three-dimensional reconstruction model of the tailings materials is established. In order to reveal the mechanical properties of tailings materials under high pressure, a high-stress triaxial experiment and high-stress conjoined consolidation permeability tests are carried out, and the strength, permeability and consolidation characteristics of the tailings materials under high stress are analyzed. To reveal the sedimentary characteristics, a large-scale model test of tailings materials is carried out. The spatial distribution of the slurry flow, siltation form, the physical and mechanical properties of the tailings, and the spatial distribution of the sandwich structure are obtained. To reveal the failure mechanism of high tailings dams, the strength criteria of tailings under high pressure are discussed through theoretical analysis and numerical models. The strength reduction stability analysis of high tailings dams is recommended. In order to reveal the clogging mechanism and service performance of tailings drainage facilities, tailings-geotextile permeability tests and microscopic observations are carried out. Fine-grained tailings are more prone to physical blockage, and the degree of chemical blockage is related to the type and concentration of solution ions. In order to promote the risk management and control technology of tailings dams, a major risk assessment and monitoring system platform for tailings dams are put forward, which can realize the extraction of basic data of tailings dams, real-time risk warning and other intelligent functions. Through the above-mentioned research activities, the level of dam building, disaster prevention and the control of large-scale high tailings ponds in China have been substantially improved.

Key words: high tailings dam, disaster mechanism, prevention methods, three-dimensional reconstruction, mechanical properties, stability, monitoring system