The Evolvement Rule And Variation Feature Feature Of Complicated Seepage Flow Field

Aiming at seepage flow governing problems related to safety of engineering closely, some new models and methods are presented for seepage flow safety monitoring based on the advanced theories and methods of mathematics and mechanics, such as fractal theory, artificial neural network, genetic algorithm, seepage flow mechanics, and so on. Then, combing with prototype observation data, the evolvement rule and variation feature of complicated seepage flow field are analyzed by analysis and back analysis methods. The main contents are as follows:(1) The behaviors and analysis methods of complicated seepage flow field. Firstly, based on the research of basic behaviors of seepage flow field in fractured rock mass, the geo-mechanical models of seepage flow are studied deeply. Then, by way of fractal geometry theory, the geometric characteristics and hydraulic behaviors are studied of water-conduction fractures. And then, an improved cut-off negative pressure method is presented to determine the free water surface of complicated seepage flow field, and the method is applied to 3-D FEM analysis of unsteady seepage flow field, and relevant numerical simulation program is developed based on divisional hybrid medium model.(2) Research on the special monitoring models of complicated seepage flow field. The hysteresis influence functions of water level and rainfall are adopted to reflect their hysteresis effect on the seepage flow, and the equivalent water level and the equivalent rainfall are obtained separately through normal distribution curve and logarithmic normal distribution curve. And following this method, the seepage monitoring models based on hysteresis effect are established. The equivalent heaving speed is put forward for reflecting the influence of heaving speed of water level on the seepage flow field, and the seepage hybrid models are obtained by considering the heaving speed of water level through 3-D steady-unsteady seepage flow FEM analysis. In the end, the basic effect of complicated seepage flow field is analyzed, and the conclusion is obtained of seepage base flow mainly derived from water pressure component and time-dependent component, and the lower boundary lines are gained of seepage base flow in dams.(3) Research on the evolvement rule of complicated seepage flow field. The influence factors and evolvement process are analyzed of complicated seepage flow field. The relationship is demonstrated of seepage flow element varying with permeability coefficients and water level. The time series model of permeability coefficients, which can implicitly describe the evolvement rule of complicated seepage flow field, is established. The concrete realization approaches and steps are elaborated to construct time series model by taking advantage of seepage base flow.(4) Research on the variation feature of complicated seepage flow field. Firstly, the aging mechanisms of impervious curtain and the malfunction mechanisms of drainage are studied. Secondly, by means of seepage flow FEM computation, the variation features are analyzed of impervious curtain and drain hole in complicated seepage flow field. Accordingly, the experiential formulas are derived of seepage flow element varying with impervious curtain's permeability coefficients. Thirdly, the variation feature is distinguished by the way of time-dependent component method, monitoring indices method and monitoring model method. In the end, the variational time-dependent component is obtained through regression analysis method and artificial neural network model.