异型构造底板改进高坝消力塘稳定性机理研究

The stability of plunge pool is the key to the success of energy dissipation and scour prevention. Many plunge pool slabs were severely damaged at home and abroad in recent years. How to effctively improved overall stability of plunge pool is very important for the security of hydro junction. One special shaped slab is put forward which has the advantages of flat slab, counter-arched slab and pervious slab in this project. For this special shaped slab, the project intends to study on the propagation law of fluctuation pressure in the complex gaps, the characteristic of hydrodynamic loads, the instability mechanics and damage mode. Combine with series model test, theoretical analysis and numerical simulation, the hydrodynamic load characteristics in plunge pool for different gap form and different vortex plate scale are analyzed with respect to amplitude domain, time domain and frequency domain. The project clarifies the propagation law of fluctuating pressure in the complex gaps, proposes the quantitative relationship between hydrodynamic load (fluctuation pressure or uplift force) and hydraulic condition (Froude number), and builds up the empirical relationship between fluctuating pressure amplitude and integral load. Based on the study of hydrodynamic load, a mathematical model is put forward, which can reflect the characteristic of dynamic loads of this special shaped slab. Various nonlinear factors and static-dynamic coupling are taken into consideration, and the instability mechanism and dynamic instability procedure are revealed, which further provides an important theoretical basis for design optimization and safety operation of slab in plunge pool.

消力塘防护结构自身的稳定是实现消能防冲的关键。近年来国内外消力塘底板发生破坏的工程实例屡见不鲜，如何有效地改进消力塘整体稳定性对确保枢纽整体安全至关重要。本研究提出一种可综合发挥平底板、透水底板及反拱底板优势的异型构造底板，针对这种型式底板开展脉动压力沿复杂缝隙传播规律、水动力荷载特性、失稳机理及破坏模式等方面的研究。结合系列模型试验、理论分析和数值模拟，从幅值域、时域和频域三个方面研究不同缝隙形式、不同涡旋板块尺度比下的消力塘水动力荷载特性，分析并阐明脉动压力沿复杂缝隙传播规律；提出水动力荷载（脉动压力或上举力）与水力条件（佛汝德数）的量化关系，建立脉动压强幅值与整体荷载的经验关系；在水动力荷载研究基础上，充分考虑多种非线性因素及静动力耦合效应，建立能反映异型构造底板受力特点及失稳机制的数学模型，揭示底板失稳机理及可能存在的破坏模式，为消力塘底板的优化设计及安全运行提供科学的理论依据。

消力塘防护结构自身的稳定是实现消能防冲的关键。近年来国内外消力塘底板发生破坏的工程实例屡见不鲜，如何有效地改进消力塘整体稳定性对确保枢纽整体安全至关重要。本研究提出一种异型构造底板即带键槽的透水底板型式，并针对这种型式底板，结合系列模型试验、理论分析和数值模拟，分析阐明了键槽及透水孔对脉动压力沿复杂缝隙传播规律的影响；统计分析了多个工程的试验成果，提出了脉动压力与整体荷载之间的经验关系，以及水动力荷载（脉动压力及上举力）与水力条件的关系；建立能反映异型构造底板受力特点的数学模型，结合水动力荷载研究成果，揭示底板失稳机理及破坏动态过程，为消力塘底板的优化设计及安全运行提供科学的理论依据。主要研究内容包括三个方面：1、异型构造底板的脉动压力沿复杂缝隙传播规律研究；2、消力塘水动力荷载特性研究；3、异型构造底板的失稳机理及破坏模式研究。通过系统的研究，得到以下的研究成果：1、从脉动压力幅值、时程线、相关特性、功率频谱等方面阐明了键槽及透水孔对脉动压力沿缝隙传播规律的影响，分析了异型构造底板提高消力塘底板稳定性的原因；2、对多个工程的模型试验成果进行统计分析，得到脉动压力与上举力之间的经验关系，以及上举力与水力条件之间的关系；3、建立能充分考虑多种非线性因素及静动力耦合效应的数值模型，揭示了透水底板以及带键槽的透水底板的内因失稳和外因失稳机理；分析了静力失稳、动力失稳和断裂劈裂破坏三种破坏模式。研究成果中有3篇被SCI/EI收录，9篇核心期刊，3项授权发明专利，还有2篇SCI刊源论文在投，达到预期的研究成果。