Multi-hierarchical fuzzy judgment and nested dominance relation of rough set theory-based environmental risk evaluation for tailings reservoirs

Environmental risk assessment of tailings reservoir assessment system is complex and has many index factors.In order to accurately judge surrounding environmental risks of tailings reservoirs and determinate the corresponding prevention and control work,multi-hierarchical fuzzy judgment and nested dominance relation of rough set theory are implemented to evaluate them and find out the rules of this evaluation system with 14 representative cases.The methods of multi-hierarchical fuzzy evaluation can overall consider each influence factor of risk assessment system and their mutual impact,and the index weight based on the analytic hierarchy process is relatively reasonable.Rough set theory based on dominance relation reduces each index attribute from the top down,largely simplifies the complexity of the original evaluation system,and considers the preferential information in each index.Furthermore,grey correlation theory is applied to analysis of importance of each reducted condition attribute.The results demonstrate the feasibility of the proposed safety evaluation system and the application potential.

Applied research of correspondence analysis method in waste tailings reservoir heavy metal pollution monitoring points optimization

In order to optimize monitoring points and monitoring factor, the relationshipbetween pollutants and soil sample were established by correspondence analysis.Thestudy results show that the reflecting monitoring points and monitoring factors in thegraphic on the same factor axis can clearly express the intrinsic link between pollutantsand monitoring points and distribution characteristics.To determine the main monitoringpoint and the main monitoring indicators can reduce and optimize the number of monitoringpoints under the premise of ensuring the typical and representative of monitoring data.Using the correlation of pollutants can reduce the number of monitoring indicators and improvethe effectiveness of data collection.

A TVD discretization method for shallow water equations:Numerical simulations of tailing dam break

In view of the disastrous consequences of tailings dam break and its unique evolutionary process in complex areas,this paper constructs two-dimensional shallow water equations,rheological equations and mathematical models of tailings sand flows on the basis of Navier–Stokes equations(N–S equations).It performs total variation diminishing(TVD)discretization on these equations,develops forward simulation programs in MATLAB2016 and conducts numerical analyses on three kinds of dam breaks(ideal dam break,asymmetric dam break and dam break with obstacles in the downstream area).The results show that TVD discretization is effective in capturing shock waves.According to the analysis on consequences of Huangmailing Tailings Dam break,the author obtains the maximum distance of tailings sand flow,the flow rate of tailings and the time that tailings reach destinations in the downstream area,thereby providing scientific basis for disaster analyses on similar tailings dam breaks and supplying technical support for emergency rescues after disasters.