| Mineral resources play a very important role in China's energy structure.A large part of the energy comes from minerals.After the ore is sorted,the part with the least proportion of beneficial components is called“tailings”,but they can still be recycled and used.Tailings are stored in tailings ponds and they have high potential energy.Once the tailings dam broke out,huge disasters would happen.Therefore,it is necessary to take measures to reinforce and improve its stability.Fiber reinforced technology is a new technology for the reinforcement of tailing dams.A combination method of indoor testing and numerical simulation was adopt in this paper to add different basalt fiber lengths?3,6,9,12mm?and contents?0.6%,0.9%,1.2%,1.5%?into different dry density(1.42g.cm-3,1.52g.cm-3,1.64g.cm-3)tailings samples.Then direct shear test,consolidation test and permeability test were applied to fiber-reinforced tailings to study its'strength,consolidation,and permeability properties.At the same time,combined with Xiangchong tailings project,numerical analysis software GeoStudio was took to analyze the stress field,seepage field and stability of Xiangchong tailings dams under different fiber lengths and contents,conclusions are reached as follows:?1?Basalt fiber reinforcement can increase the shear strength of tailings,and with the increase of fiber length,there will be an“optimal value”.In this paper,the shear strength reaches the“optimal value”when the fiber length is 6mm.?2?The addition of fibers can enhance the cohesion of the tailings.At the same content,the cohesion increases firstly and then decreases with the increase of the fiber length.Then the“optimal value”appears,and it gains the maximum increase when the fiber is 9mm.With the same fiber length,the cohesion increases monotonously with the increase of the content.In this experiment,the increase is most significant when the fiber content is 1.5%.The internal friction angle is less affected by the additional fibers.At the same fiber content,the internal friction angle enhance along the length and an“optimal value”would appear.The internal friction angle of reinforced tailings with fiber content of 1.5%or fiber length of 6 mm is always greater than that of pure tailings.?3?The compression coefficient of fiber-reinforced tailings has been improved compared with that of pure tailings.At the same content,although the compression coefficient fluctuates slightly,the overall trend is still increasing.The fibers can elevate the compression index of the reinforced tailings,but at the same content,the effect of fiber length on the compression index is not very obvious.When the fiber length is6mm,the compressive modulus decreases monotonously with the increase of the content,and the compression modulus is always smaller than that of pure tailings.?4?The permeability is always smaller than that of pure tailings at fiber content0.6%,and greater than that of pure tailings when content is greater than 0.6%.?5?Numerical simulation results show that fiber reinforcement can improve the safety factor of the tailings dam,but the effect varies under different fiber parameters.The safety factor reaches the“optimal value”when the fiber length is 6mm and the content is 1.5%. |
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