Research On Chaos And Safety Of Nonlinear System For Tailings Dam

The safety of tailings dam is an important subject in the field of mine. In this dissertation, the safety of tailings dam is researched deeply and thoroughly for the first time in nonlinear dynamics and system science based on the review of researching on tailings dam at home and abroad. The purpose of this work is to reveal safety mechanism and bring forward safety method for tailings dam.The evolution of the saturation line is a new research problem. In this dissertation, the largest Lyapunov exponents and the correlation dimension are applied to analyze the monitoring data of the saturation line of tailings dam in Yinshan lead-Zinc Mine and No. 2 tailings dam in Dexing Copper Mine. The results show that the evolution of the saturation line is a chaos system, and the state of the saturation line can be evaluated by the largest Lyapunov exponents. Not only does the work reveal evolution essential of the saturation line but also point out a new way to analyze the monitoring data. The evolution of the saturation line can display in the dimension of both time and space. Considering the slope angle of tailings dam, a coupled map lattices model is proposed creatively to describe the spatiotemporal evolution of the saturation line on the basis of one-way coupled map lattices. Under the given initial-condition and boundary condition of the saturation line, the nonlinear dynamic of the new model is analyzed. The results indicate that the complex spatiotemporal behavior exists in the evolution of the saturation line which can be influenced remarkably by slope angle.According to the fact that the saturation line evolutionABSTRACTexists chaos state which gives affection to tailings dam safety in turn, a method of controlling chaos is put forward based on OGY method(weak perturbation). The essence of this method is to analyze the largest Lyapunov exponents and use to discriminate the change of chaotic character in time series before and after superposing a periodic vibration, and further realize chaos control. With this method, the monitoring data of the saturation line of tailings dam in Yinshan Lead-Zinc Mine are analyzed. The results show that the chaos can be restrained by superposing a periodic vibration. Therefore, controlling chaos in tailings dam system can be realized by the engineering measure of periodic control.The tailings lenticle which is a key factor reflecting the sedimentation state of tailings dam, has great influence on the state of saturation line. In order to disclose the regularities of distribution of tailings lenticles, twelve geological explorative cross-sections which belong to seven tailings dams are analyzed with box dimension. The results make clear that the distribution of tailings lenticles has fractal character, and the values of lenticles box dimension reflect the sedimentation state of tailings dam.The saturation line monitoring, which is done by manual usually with piezometric tube, is the main investigation item in tailings dam. In order to monitor the saturation line, an automatic monitoring technique and a shallow refractive seismic method are studied. Both of them have better effect on monitoring.To solve the prediction problem of unequal interval sequence which appears usually in monitoring data of tailings dam, the Time and Data Separation Approach is put forward creatively in such a way that lets the time be separated from the data to gain the time sequence and data sequence, and then combines both time sequence and data sequence respectively with the interval sequence for constituting Time and Data Model, and finallyIVsynchronously makes prediction. According to the method, GM(1, 1) and Error Model of Time and Data are analyzed. For example, the trend of the seepage flow is analyzed in No. 1 tailings dam of Dexing Copper Mine, and the results indicate that the model can predict effectively. The Grey theory is also used in chaos analysis in this dissertation.Flood prevention is emphasized in the safety management of tailings dam. According to the principle of...