Research On Coupled Dynamics Analysis And Health Diagnosis For Protecting Structure In High Dam Plunge Pool

The safety of protecting structure in high dam plunge pool is the key to success or failure of energy dissipation, there is no lack of the destructive example at home and abroad. Working and destruction mechanism of protecting structure in high dam plunge pool is very complicated. It is coupling effect result between hydrodynamic characteristics of high speed streams and structural dynamics characteristics of protecting structure. This paper studies hydrodynamic characteristics in high dam plunge pool and numerical value imitates for coupled dynamics analysis by model experiment, prototype observation and numerical analysis to open out force characteristics, working mechanism and failure dynamic process of protecting structure in plunge pool. Basing on that, mechanical analysis result, expert experience and artificial intelligence (AI) technology are organically amalgamated to suggest the health diagnosis method for protecting structure in high dam plunge pool. The main achievements include as follows:(1)With research results of hydraulic jump and impinging jet,flow patterns in stilling basin and plunge pool are analyzed in detail, the distributing characteristics of mean pressure and fluctuating pressure are investigated.(2)It is analyzed in the paper of the characteristics of the propagation of the pressure wave within the contraction joints among slabs and cracks among slabs and bedrock. Influences on fluctuating pressure are especially studied by width of joints and cracks.(3)When water-stop is failure, coupling mechanism between osmotic pressure under slabs and hydrodynamic pressure upper slabs is studied. Influences on time averaged pressure, fluctuating pressure in each area under slabs are analyzed by osmotic pressure coupling. That is also investigated the uplift forces changing with different way of water-stop failure.(4)Forecast ways of maximal uplift forces acting on slabs or slope in stilling basin and plunge pool are investigated. Influences on the uplift forces acting on the slabs by fluctuating pressure integral scale, the size of stilling basin slabs and correlation characteristics for fluctuating pressure upper and under the slabs are studied systemically. Basing on that, this paper discusses the size optimization of stilling basin slabs and analyzes the reason for uplift forces decrease of the pervious slabs.(5)The steady losing and destroying process, stability calculation pattern of slabs in plunge pool and inherent relationship between them are analyzed,stability control indexes for slabs in plunge pool are investigated.(6)Prototype observation for the flood discharge vibration of protecting structure in high dam plunge pool is carried out to analyze fully dynamic respond characteristics of protecting structure working regularly.(7)The paper defines the response characteristic of dynamic displacement about stability failure process for plunge pool slabs, the method is proposed by means of dynamic displacement response to discriminate the stability of plunge pool slabs. Based on bond-slip theory, nonlinear contact theory and fluid-structure coupling theory, coupling three dimensional finite element model about plunge pool slabs, water, bedrock and anchor bar is established, limiting dynamic displacement considering phases of stability failure is studied in this paper, the response characteristic of dynamic displacement is analyzed in virtue of prototype observation results, and stability of plunge pool slabs are predicted.(8)The box dimension for slabs vibration curve in plunge pool of working regularly and the different stage of failure dynamic process is calculated. The vibration feature is analyzed and compared in time-amplitude-frequency domain. The results demonstrate that the fractal dimension is sensitive to abnormal vibration of slabs in plunge pool. The main malfunction signals are distinguished and analyzed using fractal box dimension to make it clear that the inner link between fractal dimension and the main malfunction characteristic.(9)The results of model experiment, prototype observation and coupled dynamics numerical simulation are synthesized. Mechanical analysis result, expert experience and artificial intelligence (AI) technology are organically amalgamated to extract sensitive characteristic variable about protecting structure failure. The paper puts forward theoretical model, monitoring indexes for safety monitoring of the high dam flood discharge protection structure, establishes health diagnosis system for protecting structure in high dam plunge pool.