| Tailings dam is the peripheral dam body building of tailings pond for storing tailings and water,which generally refers to initial dam and accumulation dam.Due to the possibility of dam break or leakage of tailings dam,tailings pond is a potential hazard source with huge potential energy.The main research content of this paper: Based on the randomness of tailings and dam building material parameters,this paper discusses the safety and stability of an old tailings pond in Yunnan Province after selecting a site to build a new tailings dam up to 198 m downstream,so as to upgrade the tertiary pond to the secondary pond.Firstly,the physical properties,static and dynamic properties of tailings dam accumulation materials and tailings materials are analyzed by indoor tests.Then,on the basis of considering the random characteristics of tailings material parameters,the seepage characteristics,static stability and dynamic stability of tailings pond are simulated and calculated.The main results are as follows:(1)The natural density,permeability coefficient and compression modulus of tailing silty clay are the smallest,which indicates that the permeability and deformation resistance of tailing silty clay are poor.Tailings dam material and gravel soil have excellent physical properties,which are important materials for foundation.(2)The maximum dynamic shear modulus of tailing silt and tailing silty clay increases linearly with the increase of confining pressure.The dynamic elastic modulus ratio decreases with the increase of shear strain,and the smaller the confining pressure is,the more obvious the decreasing trend is,while the damping ratio increases with the increase of confining pressure.(3)In the limit equilibrium method,the calculation results of M-P method and Bishop are higher,and it is safer to use Swedish arc method to calculate the stability.Comparing the safety factor calculated by the strength reduction method with the limit equilibrium method,it is found that the minimum safety factor of the new tailings reservoir area is indeed greater than that of the old tailings reservoir area,so the stability of the new reservoir area is greater than that of the old reservoir area.If production is carried out at this time,pay attention to the detection of the stability of the old tailings reservoir from time to time;Under #1 and #3 working conditions,the calculation results of Monte Carlo method are in good agreement with those of traditional limit equilibrium method and finite element method.Under other working conditions,the calculation results suddenly surge,but they are still far higher than the safety value specified in the specification,so the safety is good;The failure probability of old and new tailings pond under different working conditions is calculated by Monte Carlo method,which can provide reference for the later operation and maintenance of tailings pond(4)The dynamic constitutive model considering confining pressure is established,and the safety factor of tailings pond under the action of El wave and Taft wave is calculated,which shows the variation characteristics of first rising and then falling.With the accumulation dam reaching the initial dam crest,the safety factor of tailings pond drops sharply,which should be further observed.The results of dynamic stability calculation of old and new tailings pond by Monte Carlo method under different working conditions are high;When Monte Carlo method is used to calculate the dynamic and static stability under the working condition of double reservoir area,the calculation results of the new reservoir area are in good agreement with those of other methods,while the calculation values of the old reservoir area are high,which should be considered in practical engineering application.(5)The static and dynamic stability of the new reservoir area solved by Monte Carlo method is highly consistent with the traditional method.At the same time,the randomness of the calculated material parameters is fully considered in the calculation process.Therefore,the Monte Carlo method has very high feasibility in calculating the stability of the new reservoir area under the working condition of double reservoir area,while the comprehensive Monte Carlo method solves the static and dynamic stability of the old and new tailings pond under different working conditions In terms of dynamic stability,the calculation results of Monte Carlo method have high reference significance and practical value,and the accuracy of Monte Carlo method can be guaranteed under the condition of meeting the number of samples and extraction times;At the same time,Monte Carlo method can exclude other influencing factors when calculating the failure probability of tailings pond under different working conditions by sampling,and the calculation results are reliable.There are 75 figures,9 tables and 66 references in this paper. |
