锦屏一级高拱坝水垫塘底板泄洪振动响应特性研究

发布时间：2018-08-14 19:28

【摘要】：我国位于狭窄河谷的大型水利水电工程在泄洪方面的主要特点是高水头、大流量、大泄洪功率，泄洪安全问题十分突出。高拱坝水垫塘作为防护下游河床的结构，其自身在高速水流冲击下的安全性是实现消能和防冲目的的关键所在，，国内外都不乏破坏的实例。锦屏一级水电站属于典型的高拱坝泄洪、挑跌流消能的布置型式，具有水头高、泄量大、泄洪消能水力条件与水垫塘工作条件和破坏机理复杂的特点，而水垫塘泄洪消能安全问题是锦屏一级水电站运行安全的主要因素之一。本文结合高拱坝（主要为锦屏一级）水垫塘底板泄洪振动原型观测资料，利用多种信号处理技术，研究了水垫塘底板在泄洪状态下的振动特性，研究的主要内容包括：（一）锦屏一级水垫塘动水压力特性研究。结合锦屏一级水电站原型观测成果、模型试验成果，分析了锦屏一级水垫塘底板脉动压力大小、分布规律，以及脉动压力的频域特性。（二）锦屏一级水垫塘底板泄洪振动特性研究。结合锦屏一级水垫塘泄洪振动原型观测资料，重点分析了不同运行工况下底板结构振动响应的强度特征、振动过程变化特征，以及泄洪开孔方式、泄流量对底板振动强度的影响；应用现代谱估计方法，对底板的泄洪振动信号进行频谱分析，研究了锦屏一级水垫塘底板泄洪振动的主频分布规律；根据统计学原理，对锦屏一级水垫塘底板泄洪振动信号的数理统计特征进行了分析。（三）高拱坝水垫塘底板泄洪振动特性研究。结合锦屏一级、拉西瓦、二滩和溪洛渡水垫塘泄洪振动原型观测资料，应用现代谱分析方法和相关性分析方法，探讨了高拱坝水垫塘底板振动的频域特性及相关性特性。（四）锦屏一级水垫塘泄洪振动响应数值模拟计算与安全监控指标。基于有限元原理和计算方法，在ANSYS中建立锦屏一级水垫塘底板的有限元模型，采用原型和模型试验中实测的水流脉动荷载加载到有限元模型上，利用原型荷载计算的结果和实测的原型振动位移数据比对，验证计算模型的可靠性，再对极限泄洪工况下底板的振动位移进行了动力响应数值模拟计算，并对计算结果进行了分析。最后，综合原型观测成果，结合模型试验、数值模拟计算结果，并借鉴其它工程经验，提出了锦屏一级水垫塘底板各安全预警等级下各个监测指标的范围。
[Abstract]:The main characteristics of large water conservancy and hydropower projects in the narrow valley in China in flood discharge are high water head, large discharge, large flood discharge power and flood discharge safety problems. As the structure of protecting downstream riverbed, the safety of high arch dam water cushion pond under the impact of high speed water flow is the key to achieve the purpose of energy dissipation and erosion prevention, and there are many examples of destruction at home and abroad. The first stage hydropower station in Jinping is a typical high arch dam for flood discharge and energy dissipation. It has the characteristics of high head, large discharge, complex hydraulic conditions of flood discharge, working conditions and failure mechanism of water cushion pond. The safety of flood discharge and energy dissipation in water cushion pond is one of the main factors for the operation safety of Jinping I Hydropower Station. In this paper, the vibration characteristics of the bottom slab of a high arch dam (mainly Jinping 1) under flood discharge are studied by using various signal processing techniques. The main contents are as follows: (1) study on dynamic pressure characteristics of Jinping first class water cushion pond. Based on the prototype observation results and model test results of Jinping I Hydropower Station, the size, distribution law and frequency domain characteristics of fluctuating pressure on bottom plate of Jinping first stage water cushion pond are analyzed. (2) study on the characteristics of flood discharge vibration of the bottom plate of the first stage water cushion pond in Jinping. Based on the prototype observation data of flood discharge in Jinping primary water cushion pond, the intensity characteristics of vibration response of floor structure under different operating conditions, the variation characteristics of vibration process, and the opening mode of flood discharge are analyzed. The effect of discharge on the vibration intensity of bottom plate, the frequency spectrum analysis of flood discharge vibration signal of bottom plate by using modern spectrum estimation method, the main frequency distribution law of flood discharge vibration of bottom plate in Jinping first class water cushion pond are studied. The mathematical and statistical characteristics of flood discharge vibration signals of the bottom plate of the first stage cushion pond in Jinping are analyzed. (3) study on the characteristics of flood discharge vibration of bottom slab of water cushion pond of high arch dam. Based on the prototype observation data of flood discharge vibration of water cushion ponds in Jinping class, Laxiwa, Ertan and Xiluodu, the frequency domain and correlation characteristics of bottom vibration of water cushion ponds of high arch dams are discussed by using modern spectral analysis method and correlation analysis method. (4) numerical simulation calculation and safety monitoring index of flood discharge vibration response of Jinping water cushion pond. Based on the finite element principle and calculation method, the finite element model of the bottom plate of the first stage water cushion pond in Jinping is established in ANSYS. The flow pulsating load is loaded into the finite element model by using the prototype and the measured flow pulsation load in the model test. The reliability of the calculation model is verified by comparing the results of the prototype load calculation with the measured data of the prototype vibration displacement, and then the dynamic response numerical simulation of the vibration displacement of the bottom plate under the limit flood discharge condition is carried out. The calculation results are analyzed. Finally, based on the prototype observation results, combined with model tests, numerical simulation results and other engineering experiences, the range of monitoring indexes for each safety warning level of the bottom plate of the first stage cushion pond in Jinping is put forward.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV653

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