【摘要】：高壩大庫水電工程是水資源綜合利用的需要,隨著高壩建設(shè)的發(fā)展,泄洪引發(fā)的振動(dòng)問題備受關(guān)注。由于高壩大庫泄洪落差大,巨大的下泄水體能量引起的水流脈動(dòng)荷載會(huì)誘發(fā)泄流結(jié)構(gòu)及其他水工建筑物產(chǎn)生振動(dòng),這種振動(dòng)會(huì)由大壩上部結(jié)構(gòu)傳遞至大壩基礎(chǔ),進(jìn)而通過地基傳遞至周邊場地,當(dāng)?shù)竭_(dá)一定能量時(shí),會(huì)對(duì)場地建筑物的結(jié)構(gòu)安全以及周邊環(huán)境和附近居民的身體心理產(chǎn)生不利影響。然而,以往更多的是考慮水工結(jié)構(gòu)自身的泄洪振動(dòng)安全問題,對(duì)場地振動(dòng)鮮有研究。針對(duì)這一現(xiàn)象,本文從結(jié)構(gòu)振動(dòng)系統(tǒng)的輸入(泄流激勵(lì))、結(jié)構(gòu)(泄流結(jié)構(gòu)-場地振動(dòng)傳播系統(tǒng))和輸出(振動(dòng)響應(yīng))三者相互關(guān)系入手,采用原型觀測、數(shù)值模擬和物理試驗(yàn)相結(jié)合的研究方法,對(duì)多振源泄流脈動(dòng)荷載聯(lián)合誘發(fā)場地振動(dòng)的振源特性、振動(dòng)傳播規(guī)律以及場地振動(dòng)響應(yīng)預(yù)測方法開展研究。取得以下成果:(1)分析了高壩泄洪引發(fā)場地振動(dòng)現(xiàn)象的成因。基于泄洪誘發(fā)場地振動(dòng)原型觀測體系,對(duì)比研究背景振動(dòng)情況下地脈動(dòng)作用對(duì)場地的影響與泄洪情況下水流對(duì)場地的影響,評(píng)估場地土體動(dòng)力特性和自振特性,研究泄洪誘發(fā)場地振動(dòng)分布情況以及局部場地條件下的振動(dòng)放大效應(yīng)。(2)研究了泄洪誘發(fā)場地振動(dòng)振源特性。通過引入時(shí)間-小波能量變換以及交叉小波變換方法,對(duì)泄流結(jié)構(gòu)與場地振動(dòng)信號(hào)中的水流脈動(dòng)能量進(jìn)行檢測,識(shí)別場地振動(dòng)主振源。建立不同振源時(shí)域和頻域相關(guān)關(guān)系,分析各振源間的時(shí)-頻域空間相關(guān)特性。建立各振源與場地振動(dòng)的時(shí)域和頻域相關(guān)關(guān)系,從振動(dòng)能量同步變化角度,定量分析各振源對(duì)場地振動(dòng)的貢獻(xiàn)。(3)研究場地振動(dòng)傳播規(guī)律。建立了“多振源-泄流結(jié)構(gòu)-地基-場地”有限元-無限元耦合動(dòng)力分析模型。該模型很好的處理了振動(dòng)波在無限域的傳播問題,解決了大型復(fù)雜場地模擬的相關(guān)問題,其計(jì)算結(jié)果與原型觀測結(jié)果吻合程度高。通過有限元-無限元耦合模型,研究了多振源激勵(lì)誘發(fā)場地振動(dòng)沿復(fù)雜河谷向下游傳播及向地基傳播(衰減、放大)的規(guī)律。在此基礎(chǔ)上,進(jìn)一步研究了不同振源影響下的場地振動(dòng)傳播特性。(4)研究建立場地振動(dòng)預(yù)測方法�；趫龅卣駝�(dòng)振源特性及振動(dòng)傳播規(guī)律,建立了多振源聯(lián)合輸入下基于傳遞函數(shù)的“噪聲修正”場地振動(dòng)預(yù)測體系。結(jié)果表明,該體系能夠預(yù)測場地振動(dòng)強(qiáng)度與頻譜特性,解決了噪聲影響下多振源聯(lián)合輸入系統(tǒng)預(yù)測難題。同時(shí)提出一種改進(jìn)的EEMD和小波閾值聯(lián)合濾波方法,該方法降噪能力強(qiáng),能準(zhǔn)確保留振動(dòng)信號(hào)的有用信息,為場地振動(dòng)的預(yù)測提供了保障。總之,高壩泄洪時(shí)不同泄水建筑物產(chǎn)生的水流脈動(dòng)荷載是引起下游場地振動(dòng)的主要原因。不同振源的振動(dòng)特性不同,但又相互影響相互作用。不同泄洪方式,不同的場地土體,振源對(duì)場地振動(dòng)的貢獻(xiàn)以及在傳播過程的衰減與放大規(guī)律有所不同。基于場地振動(dòng)振源特性及振動(dòng)傳播規(guī)律建立的場地振動(dòng)預(yù)測體系,在時(shí)域和頻域內(nèi)預(yù)測場地振動(dòng),可以為設(shè)計(jì)人員選擇合理的泄洪調(diào)度方式提供依據(jù),具有強(qiáng)烈的實(shí)際意義。
[Abstract]:With the development of high dam construction, the vibration caused by flood discharging has attracted much attention. Due to the large discharging drop of high dam, the fluctuating load of water flow caused by the energy of huge discharging water body will induce the vibration of discharge structure and other hydraulic structures, which will be caused by the vibration of the dam. When a certain amount of energy is reached, it will have a negative impact on the structural safety of the site buildings, the surrounding environment and the physical and mental health of the residents nearby. Aiming at this phenomenon, this paper begins with the relationship between the input (discharge excitation), the structure (discharge structure-site vibration propagation system) and the output (vibration response) of the structural vibration system, and adopts the method of prototype observation, numerical simulation and physical experiment to study the site vibration induced by the combined discharge pulsating load of multiple vibration sources. The results are as follows: (1) The causes of site vibration induced by flood discharge of high dams are analyzed. Based on the prototype observation system of site vibration induced by flood discharge, the influence of ground pulsation on site under background vibration and the effect of water flow on site under flood discharge are compared and studied. The influence of the site is evaluated, the dynamic and natural vibration characteristics of the soil are evaluated, and the distribution of the site vibration induced by flood discharge and the amplification effect under local site conditions are studied. (2) The source characteristics of the site vibration induced by flood discharge are studied. The pulsating energy of water flow in the dynamic signal is detected to identify the main vibration source of the site.The time domain and frequency domain correlations of different vibration sources are established,and the time-frequency domain spatial correlations between the vibration sources are analyzed.The time domain and frequency domain correlations between the vibration sources and the site vibration are established. Dynamic contribution. (3) Study the law of site vibration propagation. A finite element-infinite element coupled dynamic analysis model of "multi-source-discharge structure-foundation-site" is established. The model can well deal with the propagation of vibration wave in infinite domain, and solve the related problems of large complex site simulation. The calculated results are in good agreement with the prototype observations. Based on the coupled finite element-infinite element model, the propagation (attenuation, amplification) of site vibration induced by multi-source excitation along complex river valley is studied. The propagation characteristics of site vibration under the influence of different vibration sources are further studied. (4) The prediction method of site vibration is established. Based on the characteristics of vibration sources and the law of vibration propagation, a noise-corrected site vibration prediction system based on transfer function is established. The results show that the system can predict the site vibration intensity and spectrum characteristics, and solve the prediction problem of multi-source joint input system under the influence of noise. D and wavelet thresholding combined filtering method, this method has strong noise reduction ability, can accurately retain useful information of vibration signals, and provides a guarantee for site vibration prediction. The contribution of vibration sources to site vibration and their attenuation and amplification laws are different in different flood discharge modes, different site soils, and the propagation process. It is of great practical significance to provide reasonable basis for flood discharge dispatching.
【學(xué)位授予單位】：天津大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TV698.1
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本文編號(hào)：2218423