Since the slope deformation has the characteristics of both trend evolution and fluctuation variation at the same time, the internal and external dynamical actions acted upon slope which may all cause trend evolution and fluctuant variation are divided into controlling action of slope equilibrium relation and dynamical variable action. Then based on the suggested expressions of the controlling action and dynamical variable action, a nonlinear dynamic model of slope deformation is established. Finally, a case study reveals that the model can simulate the complicated process of slope deformation well.
The deformation of slope is controlled by internal factors such as physical and mechanical characteristics of rock and soil, and also influenced by external factors such as weather condition and human's engineering activities. Because of the complexity of the internal and external factors' actions, the slope deformation process is very complicated accordingly. So the deformation evolution model cannot be established easily. Since all kinds of internal and external actions influence the process of slope deformation, the deformation-time process involves every trace of all actions, which is valuable "deformation information". So we can study slope deformation and establish its model by means of observed deformation-time data. From observed data of all sorts of slope deformation, it can be observed and concluded that the slope deformation has the characteristics of both trend evolution and fluctuation variation at the same time. According to the characteristics of trend evolution and fluctuation variation, we can get these conclusions: On one hand, trend evolution is the main component of slope deformation, it means that slope deformation tends to maintain stable or become instable. It may be of a combined style of accelerating, decelerating, and approximate uniform variation. Trend evolution reflects the dynamical changes of internal and external actions, such as deterioration of mechanical properties, continuous rainfall, excavation, or reinforcing. On the other and, fluctuation variation also reflects the dynamical changes of internal and external actions, and it has two features: 1 stochastic abrupt occurrence, such as deformation start caused by heavy rain: 2 periodicity, such as deformation caused by seasonal fluctuation of underground water. Therefore, along with the characteristics of slope deformation and its internal and external actions, the analysis of slope deformation process is a nonlinear problem. In recent years, some progresses have been made on the nonlinear study of slope deformation (Cui & Li,1999., Qin. et al,1993; Qin,2000; Qin & Wang,2000; Zhang,1999: Zhou,2000). In this paper, a nonlinear dynamical model about slope deformation is presented based on analysis of characteristics of slope deformation and its internal and external actions.
The model has been applied to analyze the monitoring deformation data from the ship lock's high slope of Three Gorges Project in China. By the following steps, we can obtain three kinds of curves: observed deformation curve, fitting and predicting curve and model auto-generating curve, the last two are obtained based on calculation of the model's value in studying slope deformation.
