Stability Analysis And Evaluation Of Shrub-repaired Iron Tailings Dam

There are more than 200,000 tailings ponds in the world,including more than 15,000 in China,with a stock of 20 billion tons of tailings.Tailings pond is a major source of danger and pollution of mine.Once the dam break,it will cause severe damage to the industrial and agricultural production,people’s life and property safety as well as the surrounding ecological environment,resulting in huge disaster losses and serious environmental problems.At present,about 40% of tailings ponds in China have been comprehensively treated,and the core content of the treatment is the safety stability and ecological restoration of tailings dams.Plants can prevent soil erosion,purify air,repair ecology and beautify the environment,and also have a significant impact on the stability of rock and soil slope.In order to ensure the safe and stable operation of the tailings dam after comprehensive environmental treatment,it is of great practical significance to analyze and evaluate the stability of the shrubby iron tailings dam.In this paper,through model experiment and field investigation,the background data of vegetation characteristics,stratigraphic structure and related environmental factors of tailings ponds are obtained,and the relevant research is carried out on the basis of the paper.The main research contents include:(1)This paper expounds the basic characteristics of on-site tailings ponds as well as the ecological environment and geological environment problems caused by it.The physical and chemical properties of tailings soil were tested,and the nutrient levels were determined by Nemiso index.(2)According to the actual slope height,slope ratio and stratigraphic structure of tailings ponds on site,a similar model of tailings ponds was built.Based on the loess mixing method,soil matrix in the model was improved.What’s more,shrubs,sea-buckthorn and robinia pseudoacacia were planted,and the plant growth status are recorded.(3)The physical and mechanical indexes of root-soil composite tailings soil are tested,including the factors of internal friction,cohesion,height and so on.The tensile strength of root strips was tested,and the growth indexes were measured,such as biomass,main root length,stem height,rhizome,etc.Soil samples were collected in the model and field after restoration,and SEM analysis was conducted to observe the morphology changes of soil microstructure in different restoration years.(4)Refer to the field survey report,the formation physical and mechanical parameters are determined.According to the results of tailing compound soil and the root strip,the soil physical and mechanical parameters and the root strip parameters are determined.According to the specifications,the calculation models of different levels of tailings dams are established to analyze the influence of different dam height and slope ratios on the stability of phytoremediation method.(5)The basic calculation principle of slope seepage static force is expounded,and the Geostudio simulation program is selected to set up the the stability analysis model under the effect of bush repair in Xiaoxigou tailings dam of Waitoushan iron mine.The safety coefficient is calculated,the stability of the on-site tailings dam is evaluated,and the according results are obtained.