This paper aims to avoid the tampering or leakage of sensitive data in a distance education platform. To this end, an intelligent identity authentication model was proposed to realize continuous user authentication, and high security infrastruc-ture was designed for distance education platform based on the proposed model. The experimental evaluation shows that the proposed infrastructure based on pri-vate cloud can greatly improve the security of distance education platform. Suf-fice it to say that the research findings provide new insights into the security of distance education.

Cold region covers over 50% all over the world. As an indispensable part of the project, concrete is greatly affected by temperature during the curing process. In this paper, through the orthogonal experiment design, we studied the mixing temperature, steel fiber, and water reducing agent dosage on concrete mixture slump; the influence of curing temperature, steel fiber, water reducing agent, and accelerating agent content on compressive strength of concrete; and the influence of the final microstructure by scanning electron microscopy (28-day concrete, analysis of the degree of hydration reaction). The results show that the slump of concrete increases with the amount of water reducing agent. Mixing temperature and steel fiber content have little effect on the workability of the mixture. Curing temperature has a significant effect on the growth of concrete compressive strength. The higher curing temperature is within 0∼20°C, the faster the growth of concrete strength is. The longer the age of concrete, the greater the compressive strength. The content of water reducing agent and accelerating agent only has a significant effect on the early strength of concrete, while the content of steel fiber has a great effect on the late strength of concrete. Curing temperature affects the degree of hydration reaction of concrete. The higher the curing temperature, the more the cementing substances produced by hydration reaction of concrete, the higher the degree of hydration reaction, and the higher the strength of concrete. The research results are helpful to improve the mine support operation in high-cold and high-temperature difference area.

In order to study the influence of elevation on the slake durability index of the quartz mica schist, the quartz mica schist with different elevations on the east slope of the Manjiazhai open-pit mine is taken as the research object, and based on laboratory tests and statistical analysis, the variation of negative correlation between the slake durability index and elevation is obtained. The disintegration mechanism of quartz mica schist at different elevations is also discussed. The test results show that the disintegration characteristics of quartz mica schist at different elevations are related to its mineral composition, fissure channel size, and rock damage effect. As the slope height increases, the ratio of mica to quartz in the rock increases, and the greater the porosity of the rock, the more fissures in the rock, the greater the permeability coefficient, and the more obvious the change of effective stress of rock under osmotic pressure. At the same time, the higher the slope elevation of open-pit mine, the longer the weathering time of rock, the higher the cumulative damage of rock, and the lower the rock slake durability index. This study provides a new idea for guiding the research on the disintegration characteristics of similar soft rock slopes in the elevation direction.

Considering the pressure-bearing mechanism of the safety helmet and as an anchored net is subjected to the surrounding rock mass, researchers should regard the support force as a safety criterion. Thus, a method for calculating the anchored mesh support parameters (mesh width and reinforcement diameter) is proposed in this paper. The method can provide a theoretical basis for selecting the technical parameters of an anchored mesh in active support in underground engineering. Calculation results show that a strong power relationship exists between the mesh width a of the anchor net and the distance h₃ from the anchor net to the top of the worker’s safety helmet, that is, , and the correlation coefficient is . Moreover, the mesh width of the anchored mesh decreases with an increase in the distance from the anchored mesh to the top of the worker’s safety helmet. The anchored mesh parameters designed and selected by this method ensure that the rocks falling from the anchored mesh pose no safety threat to the workers wearing helmets. The parameters also prevent an excessively large steel wire/steel bar diameter of the anchored mesh, which lowers support costs and makes the selected technical parameters of the anchored mesh economical and safe.

The shear factor of ore drawing is one of the important factors affecting the formation of underground debris flow, and it has an important contribution to the formation of underground debris flow. The purpose of this paper is to study the effect of mining shear factor on underground debris flow in natural caving method. Based on the research background of the underground debris flow in Plan copper mine, this paper analyzes the characteristics of the slurry material structure of the underground debris flow, the influence of drawing shear factor on formation mechanism of underground debris flow is analyzed. The results show that the slurry of the underground debris flow in Plan mine is not only a pseudoplastic fluid but also a thixotropic fluid. It is indicated that once there is shearing force in drawing, it will deform, and its viscosity will decrease with the increase of shear rate and time. It is considered that the shear force produced by the flow of ore particles first produces shear action on the paste in the shear boundary region of ore drawing, it is reduced in viscosity and increased in fluidity, so that its “Activation” and then become a flowable paste, along with the bulk ore flow through the mouth. The continuous ore drawing process will continuously shear the new moraine slurry in the ore drawing channel and continuously “Activate” the moraine slurry in the ore drawing channel, finally, a certain scale and destructive down-hole debris flow accident. This paper is the first to study the effect of ore drawing shear factor on the formation mechanism of underground debris flow. It not only broadens the research field of debris flow, but also fills up the deficiency of systematic research on underground debris flow, and provides theoretical guidance for the prevention and control of underground debris flow.