Study On Warning Model For Landslide During Ion-Adsorbed Rare Earth Ore In-Situ Leaching

There is congenital defect of the method in-situ leaching of ion-adsorbed rare earth ore,which easily lead to landslide disaster.In order to provide an effective solution for landslide warning,this paper starts with the physical and mechanical properties of the water content,density,particle size gradation,direct shear strength and permeability coefficient of rare earth minerals,and uses the experimental method to determine their values.On one hand,we analyzes their influence on slope stability,on the other hand,based on this,a water level early warning model and a cumulative displacement-time landslide warning model based on FIFC are established creatively.It provides theoretical basis for landslide warning of slope with on-line monitoring.The work done and the main conclusions obtained are as follow:?1?The water content,density,size gradation,permeability coefficient and direct shear strength of the ion-adsorbed rare earth ore were determined by experiments.The water content and density of rare-earth ores are related to the depth,in which the value of water content is between 15%²5%,and the value of dry density is between 1.1g/cm3¹.2g/cm3;the partic lsize of rare earth ore in 0.05⁰.5mm?mostly sandy soil?is about 80%,Less than 0.05mm?clay particles?accounted for about 20%,so the rare earth ore sample are both viscous soil and no cohesive soil properties,because the strength of the soil is mainly controlled by particle size gradation,and the in-situ leaching of rare earth ore changes the internal friction angle rarely.This provides a theoretical basis for simplifying the water level early warning model.The cohesive force and internal friction angle of undisturbed soil were 16.5kPa,27°,the cohesive force and internal friction angle of remolded soil are 14.14kPa and 26°.Respectively,the permeability coefficient of ion-adsorbed rare earth ore is less than 10^-3cm/s,weak permeability,which blocks the seepage of leaching solution and increases the risk of landslide.?2?The effective stress principle is used to explain the mechanism of decreasing the stability of rare earth ore slope caused by water level rising during leaching.The influencing factors of the water level early warning model are simplified by sensitivity analysis.Different slope angle?35°,40°,45°?and different cohesive force?18kPa,8kPa,4kPa?FIFC landslide early warning model was established.The early warning model combined with the slope water level monitoring,can realize automatic landslide warning of rare earth ore during in-situ leaching.?3?The change regularity of displacement over time during the deformation of landslide is analyzed.The cumulative displacement-time curve in the deformation process of rare earth ore is similar to the three stages of rock creep,they are,initial deformation stage,equal velocity deformation stage and accelerated deformation stage.An early warning model of cumulative displacement-time landslide was established.?4?Through the one-year in-situ leaching of a rare earth ore by injection test and displacement monitoring,and then get corresponding speed/acceleration.Putting them as early warning indicators,the cumulative displacement-time landslide early warning model was validated.Results show that the initial deformation phase of the speed was 0.15⁰.3mm/h.The velocity of the constant velocity deformation stage was-0.15⁰.15mm/h.The speed and acceleration of the accelerated deformation stage were 3¹0 times or even higher in the initial deformation stage.During the monitoring occured 5 times yellow warning,1 times orange warning,1 red warning.This method provides a theoretical basis for establishing the on-line monitoring and landslide early warning system of ion-adsorbed Rare-earth ore.