| Ion-adsorption rare earth mineral is listed as special protection of strategic resource, its development and exploitation has brought significant benefits, but there are potential environment problems in the region as well. Landslide disaster is the most remarkable problem in rare earth mines, which directly affects the mine safety production and economic benefits, and this may also harms the environment of downstream security in mining area, even causes casualty accident, and restricts the harmony of the regional economic development. This paper takes the in-situ leaching stope of ion-absorbed rare earth mineral as the research object, in order to reduce or avoid the impact of the landslide hazard. The main research work and conclusions are as follows:(1) Making up the blank research of mechanism of landslide disaster in rare earth mines. According to field landslide investigation of rare earth mine stope, this paper discussed the general rules and basic characteristics of in-situ leaching slope. Based on physical and mechanical parameters measured by field tests, sensitivity analysis was carried out to determine the importance of landslide factors. Combined with the feature of landslide, mechanisms were obtained.In-situ leaching stope landslide generally belongs to shallow small circle sliding, cracks appear on the slip boundary before sliding. The stability of interface between top soil layer and completely weathering layer should be evaluated to obtain stability of whole stope, and strength of In-situ leaching liquid injection is the most important controllable factor that effects the stope stability.(2) According to the general rules, features and related mechanisms of landside, the paper creativity proposed an online monitoring system theory that is suitable for in-situ leaching stope, and formulated corresponding procedures. Main monitoring parameters of online monitoring system contains surface crack, pore water pressure and earth pressure, including2types of vibrating wire and fiber bragg gratings sensors. Scale and construction methods of monitoring parameters were discussed, and implementation processes of system were established.(3) Experimental study on entity monitoring project of in-situ leaching stope online monitoring system has been conducted. Based on key monitoring area judged by three-dimensional numerical simulation method, detailed field implementation scheme was formulated. The processes of data acquisition, delivery, transmission, reception and automatic handling were verified, to achieve the system functions of remote control, multi-terminal real-time query and Automatic graphic processing. The experiments result indicated that, the architecture design of in-situ leaching stope online monitoring system is rational and reliable, scientific and feasible, extensive applicable, and can meet the long-term and real-time monitoring demand of in-situ leaching stope on rare earth mines.(4) Focused on the non-stationary and non-linear characteristics of online monitoring time series data, an innovative study of online monitoring and forecasting model was carried out. A new monitoring and forecasting model theory, combined radial basis function neural network (RBFNN) with empirical mode decomposition (EMD), was proposed to reveal the trend of monitoring parameters. According to the feasibility and accuracy validation of monitoring and forecasting model base on online monitoring data, the ability of multi-step short-term prediction (3days) was proved to be excellent. The online landslide monitoring system, which is embedded in EMD-RBFNN monitoring and forecasting model, can realize the automatic tracking prediction, and is also of great significance to the safety and production in rare earth mines. |
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